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Attentional Bias in Patients with Implantable Cardioverter Defibrillators (ICDs)

Permanent Link: http://ufdc.ufl.edu/UFE0021863/00001

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Title: Attentional Bias in Patients with Implantable Cardioverter Defibrillators (ICDs) Examining Mechanisms of Anxiety and Hypervigilance
Physical Description: 1 online resource (59 p.)
Language: english
Creator: Dixit, Neha
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: Clinical and Health Psychology -- Dissertations, Academic -- UF
Genre: Psychology thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Symptoms of anxiety and hypervigilance are prevalent in patients with arrhythmias, particularly in patients with life threatening arrhythmias such as ventricular fibrillation (VF). The treatment of choice for patients with VF is implantation of an implantable cardioverter defibrillator (ICD) which shocks patients out of life threatening arrhythmias and places them at risk for shock specific anxiety secondary to living with their device. Literature examining affective influences on attentional processing suggests that people with high levels of anxiety have biased attention towards threatening information, such that they have difficulty disengaging attention from negative or threatening stimuli. Using a modified emotional dot-probe task, we examined attentional bias in patients with ICDs comparing them to patients with atrial fibrillation (AF). Contrary to predictions, ICD patients did exhibit attentional bias towards clinically relevant information compared to AF controls, and levels of state and trait anxiety did not influence the magnitude of attentional bias in either group. ICD patients demonstrated higher levels of trait anxiety compared to AF patients as well as worse physical functioning. Additionally, results demonstrate efficacy of affective stimuli, with ICD patients rating clinical words as more unpleasant than AF controls. Overall, results suggest that this paradigm must be examined and potentially modified in greater detail to elucidate the influence of affective cue words on attentional bias in the arrhythmia population.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Neha Dixit.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Perlstein, William.
Local: Co-adviser: Sears, Samuel F.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2009-02-28

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0021863:00001

Permanent Link: http://ufdc.ufl.edu/UFE0021863/00001

Material Information

Title: Attentional Bias in Patients with Implantable Cardioverter Defibrillators (ICDs) Examining Mechanisms of Anxiety and Hypervigilance
Physical Description: 1 online resource (59 p.)
Language: english
Creator: Dixit, Neha
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2008

Subjects

Subjects / Keywords: Clinical and Health Psychology -- Dissertations, Academic -- UF
Genre: Psychology thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Symptoms of anxiety and hypervigilance are prevalent in patients with arrhythmias, particularly in patients with life threatening arrhythmias such as ventricular fibrillation (VF). The treatment of choice for patients with VF is implantation of an implantable cardioverter defibrillator (ICD) which shocks patients out of life threatening arrhythmias and places them at risk for shock specific anxiety secondary to living with their device. Literature examining affective influences on attentional processing suggests that people with high levels of anxiety have biased attention towards threatening information, such that they have difficulty disengaging attention from negative or threatening stimuli. Using a modified emotional dot-probe task, we examined attentional bias in patients with ICDs comparing them to patients with atrial fibrillation (AF). Contrary to predictions, ICD patients did exhibit attentional bias towards clinically relevant information compared to AF controls, and levels of state and trait anxiety did not influence the magnitude of attentional bias in either group. ICD patients demonstrated higher levels of trait anxiety compared to AF patients as well as worse physical functioning. Additionally, results demonstrate efficacy of affective stimuli, with ICD patients rating clinical words as more unpleasant than AF controls. Overall, results suggest that this paradigm must be examined and potentially modified in greater detail to elucidate the influence of affective cue words on attentional bias in the arrhythmia population.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Neha Dixit.
Thesis: Thesis (Ph.D.)--University of Florida, 2008.
Local: Adviser: Perlstein, William.
Local: Co-adviser: Sears, Samuel F.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2009-02-28

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2008
System ID: UFE0021863:00001


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1 ATTENTIONAL BIAS IN PATIENTS WITH IMPLANTABLE CARDIOVERTER DEFIBRILLATORS: EXAMINING MEC HANISMS OF HYPERVIGILENCE AND ANXIETY By NEHA K. DIXIT A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2008

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2 2008 Neha Dixit

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3 To my amazing grandparents whose value for learning, education and zestful spirit of adventure forged the way for higher education in the generations to come. And to my own parents and husband: Your never ending support and love through this journey will always be with me. I am eternally grateful for each of you.

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4 ACKNOWLEDGMENTS I would lik e to thank my mentors, Bill Perlst ein, Ph.D. and Samuel Sears, Ph.D., for their support, supervision, and examination of what was really important throughout my graduate school experience. You are both individuals who have made a permanent imprint on my mind, heart and values. In addition, I would like to thank the memb ers of the Clinical Cognitive Neuroscience Lab and Cardiac Psychology Lab for their willingness to give assistance whenever needed. I would like to especially thank Lea nn King RN, and Marcela Mi randa, ARNP for their efforts in aiding recruitment on this project. This research was suppor ted by a pre-doctoral fellowship from the Florida/Puerto Rico Affiliate of the American Heart Association to Neha K. Dixit.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ............................................................................................................... 4LIST OF TABLES ...........................................................................................................................7LIST OF FIGURES .........................................................................................................................8ABSTRACT ...................................................................................................................... ...............9 CHAP TER 1 INTRODUCTION .................................................................................................................. 11Overview and Study Aims ......................................................................................................11Specific Aims ..........................................................................................................................12Background and Significance .................................................................................................14Psychosocial Effects of ICD Implantation ......................................................................16Anxiety and the ICD Patient ............................................................................................ 16Arrhythmias and Hypervigilance .................................................................................... 17Anxiety as Precipitant to Shock ...................................................................................... 18Selective Attention ..........................................................................................................19Attentional Bias and Emotion ......................................................................................... 20Experimental Paradigms Exam ining Attentional Bias .................................................... 22Evidence of Attentional Bias in Anxiety Disorders ........................................................24Significance .................................................................................................................. ..........272 EXPERIMENTAL DESIGN AND METHODS .................................................................... 29Participants .................................................................................................................. ...........29Procedure ..................................................................................................................... ...........30Shock Anxiety ................................................................................................................. 31General Anxiety ...............................................................................................................31General Health-Related Quality of Life .......................................................................... 32Depression .................................................................................................................... ...32Cognitive Screener ..........................................................................................................33Reading ....................................................................................................................... .....33Experimental Task ........................................................................................................... 333 DATA ANALYSIS AND RESULTS .................................................................................... 37Data Analysis ..........................................................................................................................37Dot Probe Task ................................................................................................................37Reaction Time Data ......................................................................................................... 38Error Data ........................................................................................................................38Cue Word Valence and Arousal Ratings ......................................................................... 38

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6 Cue Word Valence Ratings ............................................................................................. 39Cue Word Arousal Ratings .............................................................................................. 39Effect of Shock on Dot Probe Task ........................................................................................39Shock and Reaction Time ................................................................................................39Shock and Error Rates .....................................................................................................39Psychosocial Data ............................................................................................................404 DISCUSSION .................................................................................................................... .....45Evidence of Attentional Bias .................................................................................................. 45Cohort Effects on Task ...........................................................................................................47Differences in Methodology ...................................................................................................48Manipulation Check ................................................................................................................49Limitations ................................................................................................................... ...........50Future Directions ....................................................................................................................51APPENDIX: WORD STIMULI USED IN TASK ........................................................................52REFERENCES .................................................................................................................... ..........53BIOGRAPHICAL SKETCH .........................................................................................................59

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7 LIST OF TABLES Table page 2-1 Mean (+standard deviation) demographic and psychological test data for VF and AF patients. ..................................................................................................................... .........36A-1 Word stimuli used in task ................................................................................................. .52

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8 LIST OF FIGURES Figure page 2-1 Example of a typical incongruent clinically relevant trial. ............................................... 363-1 Dot-probe task reaction times for VF (ICD) and AF (control) patients. ...........................423-2 Dot-probe task error rates for VF (ICD) and AF (control) patients. .................................. 423-3 Subjective ratings for cue-word valence. ........................................................................... 423-4 Subjective ratings for cue-word arousal. ........................................................................... 433-5 Dot-probe task reaction times for no s hock (ICD) and shocked (ICD) patients. ............... 433-6 Dot-probe task error rates for no s hock (ICD) and shocked (ICD) patients. .....................433-7 Average attentional bias sc ores (incongruent-congruent). Negative scores indicate decreased bias. ...................................................................................................................44

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9 Abstract of Dissertation Pres ented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy ATTENTIONAL BIAS IN PATIENTS WITH IMPLANTABLE CARDIOVERTER DEFIBRILLATORS: EXAMINING MEC HANISMS OF HYPERVIGILENCE AND ANXIETY By Neha K. Dixit August 2008 Chair: William M. Perlstein Cochair: Samuel F. Sears Major: Psychology Symptoms of anxiety and hypervigilance are prevalent in pa tients with arrhythmias, particularly in patients with life threatening a rrhythmias such as ventri cular fibrilla tion (VF). The treatment of choice for patients with VF is implantation of an im plantable cardioverter defibrillator (ICD) which shocks patients out of life threatening a rrhythmias and places them at risk for shock specific anxiety secondary to living with their device. Literature examining affective influences on attentiona l processing suggests that peopl e with high levels of anxiety have biased attention to wards threatening information, such th at they have difficulty disengaging attention from negative or threatening stimuli. Using a modified emotional dot-probe task, we examined attentional bias in patients with ICDs comparing them to patients with atrial fibrillation (AF). Contrary to predictions, IC D patients did exhibit attentional bias towards clinically relevant information compared to AF c ontrols, and levels of st ate and trait anxiety did not influence the magnitude of attentional bias in either group. ICD patients demonstrated higher levels of trait anxiety compared to AF pa tients as well as worse physical functioning. Additionally, results demonstrate efficacy of affec tive stimuli, with ICD patients rating clinical words as more unpleasant than AF controls. Overa ll, results suggest that this paradigm must be

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10 examined and potentially modified in greater de tail to elucidate the influence of affective cue words on attentional bias in the arrhythmia population.

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11 CHAPTER 1 INTRODUCTION Overview and Study Aims Each year, approxim ately 350,000 Americans experience sudden cardiac death (SCD) related to the occurrence of cardiac arrhythmias, including vent ricular fibrilla tion (VF) and ventricular tachycardia (VT; American Heart As sociation, 2004). The Implantable cardioverter defibrillator (ICD) is the treatment of choi ce for ventricular cardiac arrhythmias (Antiarrhythmic versus Implantable Device [AVID] Investigators, 1997; Moss et al., for the Multicenter Automatic Defibrillator Implantatio n Trial [MADIT] Investigators, 1996), and nearly 60,000 Americans receive an ICD each year. Although the ICD has demonstrated impressive mortality benefits, the device nonetheless presents as a potential instigator of psychological maladjustment in recipients. Th is is primarily due to the shock mechanism necessary for the device to convert potentially le thal arrhythmias. Si gnificant rates of panic symptoms (Godemann, Butter, Lampe, Linden, Werner, & Behrens, 2004) and avoidance behaviors (Lemon, Edelman, & Kirkness, 2004) have been documented among this population, as have difficulties with depr ession, anxiety, interpersonal func tioning, and stress management (Sears & Conti, 2003). Researchers have also implicated anxiety a bout the device and health related anxiety as significant predictors of psychos ocial distress (Pauli et. al, 1999; Sears, 1999). Given the high levels of susceptibility for both device related and generalized disease specific anxiety in ICD recipients, it is critical to identify areas of cognitive functioning which may be affected by such distress and may also serve to maintain or exacer bate such distress. Considerable research has shown that selective attention, the ability to attend to and ignore information in the environment, may be a critical cognitive process that is aff ected by both normal and clinical (i.e., social and

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12 specific phobic) anxiety (Compton, 2003). Emotional processing is tightly linked to levels of arousal (Damasio, 1996), such that high levels of arousal (e.g. fear, threat) may enhance attention during a threatening situ ation and low levels of arousal may allow an individual to ignore relevant information. Patients with cardiac diseas e, specifically arrhythmia s, constantly evaluate their own levels of related threat (Pauli, 1999). The nature of thei r disease state warrants critical vigilance to symptomatology, adherence to me dication regimens, knowledge of health care options and advances, and a host of medical in formation which may vary throughout the course of living with chronic cardiac disease. A ttention or vigilance to medical knowledge and personal health status is importa nt as it keeps arrhythmic patie nts focused on returning to full functioning. Too much or too little attention to such information can result in diminished physical and mental functioning. Thus, examining the levels of attenti on to cardiac specific information in ICD recipients (for whom anxiet y is directly related to physical symptomatology and device specific characteristics) may give rise to further characterizing and understanding patients beliefs and specific fears about their devi ces and disease state for future interpretation. Specific Aims The current study aim ed to examine cardiac-specific attentional biases in patients living with ICDs. Patients with ICDs provide a uniqu e perspective on the relationship among emotion, attention, and anxiety given the na ture of the acquisiti on of their symptoms. ICD recipients who are psychologically healthy prio r to implantation may experience clinical levels of anxiety following ICD implantation and the experience of ICD shock. Examining ICD patients ability to disengage attention from shock -related information is critical to their quality of life and psychosocial health. It is important for patients to redirect from negativ e material (e.g. counting their pulse, catastrophic thoughts) in order for them to retain information provided by physicians and live actively with the benefits of the device and minimize drawback. Previous research has

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13 suggested that a variety of anxi ety-disordered patients demonstr ate attentional biases towards clinically-relevant information (Derryberry & Reed, 1994) and that atte ntion to threatening information is directly related to coping style and functional st rategy. Research has demonstrated that patients with adaptive coping strategies are able to disengage better from negative disease specific information than those with maladaptive strategies. Thus, examination of attentional bias for cardiac-related informa tion in ICD recipients could prove useful in tailoring future treatments to these patients. Specific Aim 1: To determine if the implantation of an ICD in cardiac patients, the frequency of ICD shock, and generalized state or trait anxiety are associated with specific affectmediated selective attentional biases as measur ed using a variation of the Dot Probe task. Based on the literature sugges ting attentional bias towards threatening information in individuals with high levels of anxiety (i.e. state) and specifi c phobias, it is hypothesized that both levels of distress and the presence of at least one ICD shock will contribute to biased performance, reflected by disproportionately slower reaction times under clinically-relevant cued conditions compared to both arrhythmia control patients and non-ICD-related cues. Specific Aim 2: To examine if varying levels of state and trait anxiety differentially affect attentional bias in both ICD patients and arrhythmia controls Evidence suggests that living with an arrhythmia (whether life threatening or not) may increase the ex tent of ones bodily or cardiac-specific vigilance. Additionally, studies of attentiona l bias in participants with sub-clinical levels of anxiety also show a bias towards threat -relevant information. It is hypothesized that the magnitude of attentional bias to threat w ill be positively correlated with levels of state, but not trait, anxiety in both groups as dem onstrated in previous studies examining attentional biases in otherwise h ealthy individuals (Fox, Dutton, & Bowles, 2001). State anxiety has been implicated in attentiona l bias in anxiety-diso rdered individuals, whereas trait anxiety has not generally been corr elated with indices of bias in similar dot probe paradigms (Mogg & Bradley, 2002). In sum, the proposed research will examine potential selectiveattention biases to cardiacrelated information in patients who have received ICDs. The significance of this research is twofold: 1) it may enhance our understanding of atte ntional biases in patients who are potentially developing heightening anxiety and concern with bodily symptoms, thereby providing a prospective means by which to st udy natural anxietydisorder developmen t, and 2) it may provide insight into treatment of cardiac specific anxiety-related symptoms in patients with ICDs

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14 which can potentially improve their quality of life, lead to better adherence to treatment regimens, and improved understanding of their disease process. Background and Significance The following sections will first describe th e prevalence and presentation of psychosocial distress in patients with ICDs and arrhythmias. Then, the use of the dot-probe paradigm to examine attentional bias in a va riety of anxiety-disordered indi viduals will be discussed. Finally, the relationship between ICD placem ent, shock, anxiety, and attenti onal bias will be explained, including possible mechanisms fo r the observed relationship. Sudden cardiac death is an increasingly frequent occurrence among patients with cardiovascular disease, particul arly those with conditions comp romising the electrophysiology of the heart. Recent advances in device technology ha ve increased delivery of preferred treatment of life-threatening ar rhythmias. A patient is considered at ri sk for sudden death if they have had a previous cardiac arrest from which they have been resuscitated, if they have an ejection fraction <35%, if they have a history of congestive heart fa ilure, or have congenital cardiac issues such as long QT syndrome exist, where sudden death is a common outcome. ICDs are devices that prevent the heart from either going into a life th reatening rhythm or shock the heart back from a chaotic rhythm. Sears and colleagues (1999, 2000, 2001, 2002, 2003, 2004), as well as other researchers, have discussed aspe cts of psychosocial distress relate d to living with an ICD. The two domains which have been commonly examin ed are affective and mood disturbances in patients and quality of life change s in patients. Sears (2003) has re ported that the prevalence of anxiety symptoms in ICD patients is between 13-87% with rates of clinically-significant anxiety ranging between 15-38%. Rates of depression in this population are around 12-24%. Given these numbers, and the findings of researchers such as Hegal et al, (1997) who report that 30% of all recipients of ICDs have clinically-relevant de pression and anxiety, psycho social distress is an

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15 important factor to examine in the life course of these patients. While anxiety and depression do exist in this population, it is impor tant to note that rates of depr ession appear to be similar to those in the general cardiac populati on (Sears and Conti, 2003). It is the rates of anxiety and the unique development of this anxiety which di stinguishes ICD patients from other medical populations (Godeman, 2004). One of the interesting issues surrounding psychosocial distre ss in ICD patients is in the way one can attribute the distress. The CABG-PAT CH trial, examined the quality of life and psychosocial distress in recipients of ICDs versus those who did not receive ICD post bypass surgery. Researchers in this study noted signi ficant distress among the ICD group compared to the non-ICD group. Examining these data more thoroughly revealed that it was patients who received shocks who perceived th eir quality of life as diminished and contributed to the distress ratings in the group. Several othe r researchers have also implicated shock as an important contributor to psychosocial distre ss. Schron et al. (2004) showed that patients who got shocked in the first 6 months of receivi ng their device had a greater inci dence of depression and anxiety than their non-shocked counterparts. Several other factors have been implicated in poor psychosocial functioning in recipients of ICDs including age, gender, premorbid psychological functioning, and general life coping skills (Sears et al, 1999). Pauli and colleagues (1999) have shown that individuals who adopt a coping style involving catast rophizing have more psychosocial distress and are less ab le to cope with both their device but also the aspects of having a life threatening condition. Such types of distress may manifest themselves in the inability to adequately manage treatment regimens, and intake of vital medical information. The accuracy of disease perception is critical to quality of life and survival of ICD patients.

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16 Psychosocial Effects of ICD Implantation Patients with life threatening arrhythmia s face numerous medical and psychosocial challenges in todays environment. As stated previously, the advent of technology allows patients to live longer and more resilient medical lives, but in many patients the ICD comes at a price to their quality of life and mental health. Specifically, psychosocial and quality of life issues that coincide with implantation are being more carefully dissected. Anxiety and the ICD Patient Anxiety has been identified as a significant contributor to the pathogenesis of cardiac disease (Kubzansky, Kawachi, W eiss, & Sparro w, 1998). Through activation of the sympathetic nervous system and subsequent release of catech olamines, anxiety is implicated in platelet aggregation, injury of arterial lining, and release of fatty acids into the blood all of which promote the atherosclerotic process. Anxiety al so may cause injury by decreasing heart rate variability and increasing the incidence of vent ricular premature beats, thereby contributing to electrical instability. Fi nally, anxiety may trigger a myocardial infarction (heart attack) due to the association between hyperventila tion and coronary vasospasms. Behavioral mechanisms have also been established associating anxiety with health-compromising activities, such as smoking, decreased physical activity, or poor diet (Haywood, 1995; Ja nuzzi, Stern, Pasternak, & DeSanctis, 2000). Anxiety is the most common complaint among ICD patients who have been shocked. A number of studies have shown that recipients of ICDs experience psychological distress as a result of receiving one or multiple shocks. The role of classical conditioning in the presence of a predominantly neutral stimulus (non-shock ICD placement) plays an important role in the development of anxiety and psychological sy mptoms (Sears et al, 1999; Godemann, 2004). When an arrhythmia occurs, the patient receive s a high-voltage shock to the chest. This is

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17 intuitively an anxiety-provoking and fearful e xperience for patients (Herrman, von zur Muhen, Schaumann, Buss, Kemper, Wantzen, & Gonska, 1997; Luderitz, Jung, Deister, & Manz, 1996; Schuster, Phillips, Dillon, & Tomich, 1998; Sear s, Todaro, Saia-Lewis, Sotile, & Conti, 1999). Research indicates that excessi ve cardiac worry, ICD-specific fears, as well as physiological arousal are among the anxiety symp toms experienced by patients with ICDs (Sears et al., 2000). Research has shown that up to 15.9% of patient s who receive an ICD develop one or more anxiety disorders (e.g., panic di sorder, generalized anxiety disorder) after implantation (Godemann et al, 2004). Accordingly, as many as 40% of ICD patients may exhibit clinically significant symptoms of anxi ety (Sears & Conti, 2002). Arrhythmias and Hypervigilance Living with arrhythm ias of any kind can be as stressful as living with other chronic illness. What makes arrhythmias even more difficu lt to live with is the specific nature of the symptoms they produce. A patient with atrial arr hythmia, for example, may feel fluttering of the heart, tightness in the chest, and dizziness, among other symptoms. They may also feel nothing. However, the consequence of their particular a rrhythmia may be life thre atening. Most patients with atrial fibrillation (a co mmon arrhythmia in the elderly population) are on anti-coagulant therapy due to the high rates of thrombolic strokes which occur in these patients secondary to their arrhythmia. In the same regard, a patient wi th diagnosed susceptibility to supra ventricular tachycardia (SVT), ventricular ta chycardia (VT), or ventricular fi brillation (VF) may feel dizzy, faint, have difficulty breathing and feel like thei r heart is racing. If these patients have ICDs, in most cases the response to their arrhythmia will be shock. Not surprisingly, it is not only the seriousness of the condition itself in patients with arrhythmias th at contributes to anxiety and psychosocial distress, but the na ture of the symptoms which are often themselves anxiety provoking (Burke, 2004). For example, Godemann (2004) found that ICD patients who had been

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18 shocked were three times more likely to have di agnosable panic disorder and generalized anxiety disorder than their non-shocked counterparts. Evidence from the ICD literature (Pauli, 1999, Sears and Conti, 2003) shows that patients are constantly evaluating th eir level of health. Negative cognitions such as will I die from th is shock? or will by heart stop beating? are acceptable and real questions for pa tients to ask themselves. The nature of their illness requires them to question their bodies. Problems arise when patients go from healthy questioning of symptoms to an unhealthy hypervigilence of thei r bodies. These individuals focus so much on factors determining their health status (e.g. checking their pulse, counting respirations, trying to predict shock), that they forgo living and general quality of life. Ma llioux and Brenner (2002) described this phenomenon as somatosensory am plification in which patients overemphasize the responses of their parasymp athetic nervous systems to normal stimuli and then worry about their health after making an inaccurate attribution. The illusion of control which is maintained by patients who are exceptionally anxious or hyperv igilent is dangerous because it is not real. It is not based on actual physical merit and can actu ally cause increased numbers of arrhythmias, thus perpetuating the cycle of vigilance and distress. Anxiety as Precipitant to Shock Recent re search in the ICD literature points to growing evidence that stress and anxiety are themselves contributers to shock. A st udy by Shedd and colleagues (2004) examined the incidence of shocks 30 days before the attacks on world trade center and 30 days post. Findings demonstrated a 2.8 fold increase in shock after the WTC attacks among people living in Florida, while researchers examining individuals in New York City and other parts of New York found similar results at a 2.4 fold increase. Both studi es controlled for other mitigating factors which may have contributed to shocks. These numbers indi cate that traumatic life events even far from their occurrence increase stress and cause arrhythmias to occur. Dunbar (1999) also showed a

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19 relationship between aggression, ho stility and shocks leading to the suggestion that there are patient relevant personality/trait factors which co ntribute to shock. Neurochemical support of these findings has been demonstrated by Lamper t and colleagues (2004) who showed that higher levels of stress hormones (epinephrine and norep hinephrine) were correl ated with arrhythmic changes in the heart suggesting a biochemical path way which may be excited when a patient gets anxious or stressed. Collectively, greater insigh ts into anxiety processes may allow for some impact on the occurrence of shock itself. Selective Attention Selective attention is an im portant compone nt of a humans cognitive experience. The brains ability to make decisions about what in formation to attend to a nd what information to filter out is vital to maneuvering through the vast array of environm ental and internal stimuli we perceive and take in. Several researchers have examined different models of attention. Posners model of attention is well known to decompose th e components of selectiv e attention and aid in the understanding of mechanisms th at comprise this system. This model of attention views attention as a system comprised of several voluntary and involuntar y processes (Posner & Peterson, 1990; Posner & Raichle, 1994), which act in concert to orie nt a person to their environment. Selective attention is driven by the posterior attentional system that is defined as the reactive component of attention that orients a persons focus from one location to another. According to Posner, orienting is accomplishe d through three operations : disengagement from the object, movement to anothe r location, and engagement of th at new location. This model theorizes that visual spatial attention involves both facilitation and inhibition of various competing visual information. In his seminal exogenous cueing task, Posner (1988) found that presentation of a visual cue increases a subjec ts vigilance and orients them to that spatial location, thus allowing for faster target detection in that location. While a subject orients to the

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20 new location, he/she inhibits all other spatial information. Classi cal paradigms used to examine selective attention and orienting, have utili zed Posners exogenous cueing paradigm and his theoretical principles in th e experimental setting. Attentional Bias and Emotion Affective influences on infor mation proces sing is critical for human function. The adaptive function of emotion depends upon the pa rticular emotion being studied but basic emotions such as anger, fear, happiness, sadness and disgust evolved distinctly to benefit the human experience (LeDoux, 1996; Lang, Davis, & Oh man, 2000). For example, it is likely that the basic emotion of fear evolved to enable an organism to rapidly det ect and respond to danger in its environment (LeDoux, 1996). Contemporary theories of em otion argue that the initial appraisal of a situation or obj ect (as neutral, positive, or negative) is one of the major determinants of the emotional response to that situation (Lazarus, 1966; Oatley & Johnson-Laird, 1987). Since emotional appraisal of an external stimulus may also determine its importance or priority, attentional input to that stimulus may be guided by such an appraisal (Lang, Bradley, & Cuthbert 1997; Damasio, 1998; Co mpton, 2003). Thus, given the vast amount of information in our external environment it is adaptive for em otional processing of stimuli and attentional selection to be integrally related. Of particular interest to researchers who examine the in terplay between emotion and attention is the speed with which appraisals and attentional shifts are made. For example, several researchers have demonstrated that emotional processing is encoded early in the processing stream and is fairly automatic (Ohman, 1997, Zajonc, 2000). Automatic processing has been defined by a time frame between 100-300 millisec onds after the appearan ce of an emotional stimulus (Compton, 2003). Neuroimaging techniques have allowed researchers to examine brain activity during these early stages of processing. One such technique is event-related potentials

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21 (ERPs) which record fast electr ical changes in the scalp during stimulus presentation. Studies using ERPs have demonstrated that discrimi nation of emotional content (e.g. face recognitionhappy, sad, angry; provocative pictures) occurs dur ing as early as 80-160 milliseconds with the onset of the stimulus (Broomfield & Turpin (2005). Masking studies, where the emotional stimulus is imperceptible to conscious proces sing (Lang, Davis, & Ohman, 2000), have also demonstrated early detection of both the content of emotional stimuli (pleasant, neutral, or unpleasant) and intensity of the em otional connotati on (arousal). Functional neuroimaging has provided additiona l insight into the relationship between selective attention and emotion. Neural structures involved in th e early processing of emotional stimuli include the amygdala, anterior cingulate and frontal cortex (Dolan, 2000). There is a large degree of overlap between these structur es and those involved in processing selective attention. Two main neural mechanisms exis t by which emotion may guide information processing. Regions of the brain that rely on sensory information such as the visual cortex and the extrastriate cortex regulat e bottom-up influences on attenti on. During presentation of an emotional stimulus these regions show increased activity or amplification resulting in favored attentional selection to that stimulus (Mangun, Jha, Hopfinge r, & Handy, 2000). Amplification is thought to occur via bottom up input from the amygdala that reacts to emotional representation put forth. For example, Lane and colleague s (1997, 1998) found that exposing subjects to emotionallyarousing pictures increased activatio n in the visual cortex compared to neutral pictures. Others such as Pessosa and Ungerleider (2004) have found increased activation of areas such as the fusiform gyrus (also involved in visual processing) when showing subjects fearful verses neutral faces.

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22 While the amygdala sends amplifying signals to sensory cortices, ot her regions of the brain are implicated in top-down processing of emotional information to help modulate its selection. The two major brain regions involve d in selection and suppr ession of information from the amygdala are the dorsolateral and ventro medial corticies (Mangun et al, 2000). The dorsolateral region is involved in selecting and maintaining stimulus attributes in working memory (Cohen et al, 1999, 2000), while the ventro medical region is involved in registering the emotional significance of stimuli and is also involved in motivati onal and goal directed processing (Bush, Luu, Posner, 2000). The anterior cingulate which is a part of the ventromedial frontal cortex, is a structure invo lved in conflict detection and may play a role in what emotional information to let into decision making processi ng and which to leave out (Hariri et al, 2004; Whalen & Bush, 1998). Bishop and colleagues (2004) showed using an fMRI study that, individuals who were highly anxious had higher anterior cingulate cortex (ACC) activation compared to less anxious comparison subject when viewing threatening stimuli. According to the somatic marker hypothesis of Damasio ( 1994) feedback from autonomatic (emotional) responses provides critical inpu t via the amygdala to decision-making processes mediated by the frontal lobes. Given the neural mechanisms invol ved in emotional processing, theories of normal emotion have their parallel in theories of diso rdered emotions such as anxiety and depression where thinking, cognitive processi ng, and decision making has been shown to be distorted (Beck, 1976). Experimental Paradigms Examining Attentional Bias Two comm on experimental methodologies used to examine selective attention in adults are the emotional stroop task and the emotional dot probe paradigm. In both tasks, the basic premise is to orient a subjects attention to par ticular stimuli while utilizing interfering emotional stimuli to distract the subject. Together, these two tasks have been manipulated such that

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23 researchers have been able to determine the nature of both cognitive and neuroanatomical aspects of anxiety disordered individuals and th eir ability/inability to attend meaningfully to specific stimuli. Since its inception the Stroop has commonly been used as the gold standard for selective attention tasks. In this particul ar task, a subject is asked to re ad a set of emotional and neutral words and then asked to name the color of the word disregarding the words content. It has been demonstrated by numerous researchers that subj ects response latencies to emotional words are longer for subjects for whom the words have rele vance (e.g. socially relevant words for social phobias) compared to control subjects. The results indicate that the automa ticity of word naming is overridden by the emotional content of the word. In fact word naming appears to take longer when examining emotional words for people with a ffective disorders. It has been posited that the Stroop is a task of conflict detection and monitoring. Although attentional networks have been implicated in this detection process, the re sults of the emotional ve rsion of this task are often misguided and interpreted inaccurately (Alg om, Chajut & Lev, 2004). In the Stroop it is often the level of emotional content within the wo rd that drives the attentional bias and is not considered a hallmark stroop color naming effect. The emotional content of the word itself is the interfering stimulus and can vary on its level of biasing attenti on. The dot probe task, a derivative of Posners original exogenous cuing paradigm, is more commonly used to examine attentional bias in healthy and mood disorder ed individuals (P osner, 2000). The dot probe paradigm orients a persons atte ntion to a particular spatial location by the presentation of a cue prior to a target probe. In th is task individuals are asked to attend to letters or dots presented in different spatial locations on a computer screen (cue). They are then shown a target probe in the same or different location of the previous ly presented cue and asked to

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24 respond to the probe. The basic premise of the dot probe paradigm is that a persons visual selective attention can be orient ed differentially to spatial locations. A subjects reaction time measured by response latencies between cue and target (i.e., probe) detection is the main measure of their attentio nal capture. Further anal ysis of the dot probe task involves examination of response latencies subjects have to valid trials and invalid tr ials, sometimes called the validity effect. Longer response latenc ies are observed for trials where probes occur in a different location from the cue (i.e., invalid or incongruent ) suggesting that indivi duals are primed by the cue to orient their attention in one direction and have difficulty di sengaging from that location in response to the probe. The dot probe paradigm has utilized the principles of Posners shift and disengage components of attention (1980) to describe instances of disturbed selective attention during the task. The task has been manipulated in numerous ways to examine selective attention in anxious individuals mainly with the additi on of emotional cue related stimuli; usually an emotional word, face, or picture and by priming lo cations in a valid/invalid manner to create an attentional response bias. Evidence of Attentional Bias in Anxiety Disorders Individuals with anxiety disord e rs are of particular interest when examining attentional biases because of the nature of the disease st ate. Mood congruent atte ntional biases are well established in the anxiety literature (W illiams, Watts, MacLeod, &Mathews, 1997; Armony &LeDoux, 2000). It has been posited that human anxiety reflects a heightened response of the fear system (Lang & Ohman, 2000; Armony & LeDoux, 2000; Fox, Russo, Bowles, & Dutton 2001). Thus, it is adaptive for people who perceive a threat to get anxious and thereby engage neural systems to aid in the resolution of the th reat. If resolution cannot be reached, higher order brain systems (frontal cortex, et c.) must come online and create alternative response options.

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25 As such, both individuals with anxiety disorders a nd those with subclinical levels of anxiety may differentially strategize execution of action during the presence of threat (Derryberry & Reed, 2004). Major findings in the dot probe literature demonstrate that anxious individuals show a bias towards threatening faces, words, and negative pictures. A study by MacLeod, Mathews and Tata (1986) demonstrated, using an emotiona l dot probe task, that anxious patients were faster to respond to the probe ( dot) when it appeared in the loca tion where a threat-related word has just appeared (valid cue) compared a non-threat related word. This effect was disproportionately seen in anxious individuals compared to non-a nxious control participants and was specific to threat-relevant information. Th is result has been re plicated throughout the literature (see Mogg & Bradley, 2000 for review ) and suggests that th reatening information captures visual attention particul arly in those individuals who ar e especially sensitive to fearrelevant stimuli in the environment (e.g. anxious individuals). Hypervigligence to external stimuli and processes of relevance such may dive rt attentional resources away from non-threat related information and bias attention towards th reat related information. Similar findings have also been shown in non-clinical pop ulations (Fox et al, 2001). Indi viduals with subclinical levels of anxiety (high trait anxiety) have also demonstrated an atte ntional bias towards threatening information (Fox et. al, 2001, Wilson & McLeod, 2003) when compared to low traitanxious individuals. An important issue raised in th e dot probe literature is one of individual differences in anxiety-disordered patients. While some patient s may exhibit heightened attentional capture to threatening information, it has been demonstrated that some have difficulty disengaging from threatening stimuli. A series of studies ha ve shown individuals with high levels of state anxiety

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26 to have difficulty disengaging from negative or th reatening information (Amir, Elias, Klumpp, & Przeworski, 2003; Fox et al, 2001; Yi end & Mathews 2001) that is particularly releva nt to them. Personal or individual threat ther efore is an important considerat ion when interpreting dot probe findings. Other models discussing biased attentional direction (e.g. Williams, MacLeod) posit that high trait-anxious individuals or ient their attention towards th reatening information while low trait anxious individuals will or ient away from the threatening information. The shifted attentional model account proposed by Mogg and Br adley (2000), posits that regardless of level of anxiety, all individuals will direct attention away from mild threat intensity stimuli and orient towards stimuli with a high threat intensity. The observable difference between the two groups is the intermediate le vels of threat intensity. McLeod and Wilson (2003) designed a unique study in which they varied the intensity level of a variety of angry faces on a continuum of threat. Findings showed that all subjects showed greater vigila nce (longer response times) to the most extreme and intense faces. They did not show any effects at very low levels of intensity. The critical difference in this study was to interm ediate levels of angry faces. High trait anxious individuals displayed a greater vi gilance to threat compared to low anxious individuals. These findings appear to suggest another mechanistic vi ew of anxious individuals. They appear to predict that high trait anxious participants reach a threshold of subjective thre at at lower levels of perceived threat than low anxious individuals. The ability to disengage from personally re levant threat has been demonstrated in medical populations. Researchers have demonstrat ed that patients with chronic pain show attentional bias towards pain related information (e.g. words) when compared to medical counterparts who did not have chronic pain (D ehgani, Sharpe, & Nicholas, 2003; Beck et al,

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27 2001). In fact, pain patients show differential bias towards words that are related to their particular type of pain. For example, Van Damme, Lorenz, Ecclest on, Koster, DeClercq, & Crombez, 2004 showed that patient s with increased negative cogni tions about their pain were more likely to have increased response latencie s to affective pain words compared to sensory pain words. Patients rating their subjective pain experien ce as more intense (e.g., burning, stinging) showed increased respons e latencies to sensory words co mpared to affective words. Similar findings, demonstrating disproportionately increased response late ncies to clinicallyrelevant words compared to other words and comp ared to controls exist in literature examining social phobia, specific phobia, and gene ralized anxiety disorder (Compton, 2003). In sum, the dot probe literature highlights what has been interpreted as the highly anxious individuals inability to disengage from releva nt threat information as evidenced by longer response latencies during negative verses pleas ant conditions. This generally results in disproportionate slowing during c linically relevant or threat ening conditions during invalid verses valid trials. Significance The present study furthered an understanding of the relationship between anxiety and cardiac arrhythmias, specifically the role of information processing in ICD recipients. The number and proportion of individuals being implanted with ICDs is growing in this country. With new advances in technology, ICDs will increase in their favorability as treatment of choice in both arrhythmias and congestive heart failur e. Research suggests th e presence of anxiety, specifically shock-related anxiet y results in an increase in hypervigilence to bodily symptoms and health-related stress (Pau li et. al, 1999; Sears et al, 2001; Godemann, 2004). In addition, shock-related anxiety is associated with depres sion and decreased quality of life (Sears et al., 1999, 2001, 2003). ICD recipients are, by nature of the mechanism of their device and disease

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28 state biased towards potentially th reatening sensations from their bodies. Much like studies of attentional bias in pain patients, ICD recipi ents offer a unique perspective to examine the relationship between emotion and attentional bias. In addition, the present study has clinical significance in that findings may identify mech anisms by which ICD recipients may process information, particularly cardiac related informa tion, and to what degree they may over engage this information is critical to treating them. This line of research may ai d in the development of individually tailored psychosocia l interventions and the types of patient information that is offered in a clinical setting.

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29 CHAPTER 2 EXPERIMENTAL DESIGN AND METHODS Participants Thirty seven VF (ICD) patients (ages 34-80) and 41 AF patients (age s 37-80) participated in the study. Participants were recruited th rough the Electrophysiology Clinics at Shands Hospital at the University of Florida Health Scie nce Center. Per interview, all participants were right-handed native-English speakers. Our samp le consisted of 93% Caucasian, 4% AfricanAmerican, and 3% Hispanic. Potential partic ipants were excluded from the study for the following reasons: 1) Major Axis I psychopathology; 2) dementia or other neurological disease; 3) acute medical illness; 4) current use of antiepileptics or other medication known to significantly affect cognitive functi oning; 5) motor deficits that would interfere with the use of the dominant hand for performance of button pres s associated with the dot-probe task; and 6) a score of less than 30 on the Telephone In terview for Cognitive Status (TICS; Brandt, Spencer, & Folstein, 1988). All pa rticipants provided written informed consent according to procedures established by the University of Flor ida Health Science Center Institutional Review Board. Participants were compensated $10 for their time. Demographic characteristics of study participants are provided in Table 2-1. ICD and AF patients were well matched for education, t (78) = -.57, p > .68, and were screened for reading using the North American Adult Reading Test (NAART; Blair & Spr een, 1989; Nelson, 1982). ICD patients and AF patients reported similar levels of depressive symptoms on the Beck Depression Inventory, 2nd Edition (BDI-II; Beck, 1996), t (78) = -.03, p > .90. ICD patients and AF patients also reported similar levels of state anxiety state, but greater trait anxiety, compared to AF patients t (78) = 1.29, p < .04.

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30 Medical data on cardiac diagnoses, current me dication, and ICD-related information was also obtained for purposes of characterizing th e two groups. Mean ejection fraction was 35.87 ( S.D. = 14.36). Respondents medical hist ory was significant for ventri cular tachycardia (21%), ventricular fibrillation (11%), coronary artery disease (45%), and myocar dial infarction (23%). Seventy two percent of the sample had been diag nosed with congestive hear t failure. Medication use was as follows: 58% endorsed taking aspiri n, 51% Coumadin, 84% beta-blockers, 15% calcium channel blockers, 30% ACE inhibitors 20% angiotensin rece ptor blockers, 48% diuretics, 10% amiodarone, and 5% sotalol. Procedure Participants attended one 1hour testing session. Prior to the first sessio n, participants were adm inistered the TICS (Brandt et al., 1988) as an initial screen for cognitive impairment. Potential participants with TICS scores of less than 30 were excluded from the study. Using this cutoff score, the TICS has a reported sensit ivity of 94% and a specificity of 100% for distinguishing demented individuals from cognitiv ely intact individuals (Brandt et al., 1988). Thus, the TICS provided a means to exclude demented individuals from the study. No participants were excluded using this criterion during recruitment for this study. During the experimental session, all pa rticipants receiv ed a screening1 of relevant psychiatric and medical history. Participants were also screened for neurological insult that might be an exclusionary criterion. They were asked whether they have difficulty reading the newspaper to determine visual acuity problem s that might interfer e with performing the computer task. The presence and severity of depr essive symptoms were assessed via the BDI-II. 1 Participants were screened for psychiatric conditions vi a clinical interview and review of the medical record.

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31 Participants were also given several ps ychosocial measures to examine general psychological and emotional functioning. The m easures given were: (1) The Florida Shock Anxiety Scale (FSAS) was developed to assess the fear and anxiety that patients commonly have regarding the ICD and its shocks. This 16-item measure examines the cognitive, behavioral, emotional, and social impact of shock anxiety; (2) Spielberger StateTrait Anxiety Inventory (STAI), a clinical measure of anxiety; (3) SF-12, a generalized measure of health related quality of life; (4) The Left Ventricular Dysfunction Qu estionnaire (LVD-36) a cardiac specific quality of life measure; (5) The B eck Depression Inventory, 2nd Edition (BDI-II) and (6) Telephone Interview for Cognitive Status (TICS). These measures are described in detail below. Shock Anxiety The Florida Shock Anxiety Scale (FSAS): This scale was developed in the Cardiac Psychology Lab at the U niversity of Florida for a previous study to assess the fear and anxiety that patients may have regarding the ICD and its shocks. This 16-item measure examines the cognitive, behavioral, emotional and social im pact of shock anxiet y. Full psychometric validation available (Kuhl, Dixit, Wallace, Sears, & Conti, 2005). General Anxiety State-Trait Anxiety Inventory (STAI): The STAI is a 40-item self-report questionnaire designed to measure both state and trait anxi ety (Speilberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983). Trait anxiety is defined as a relatively enduri ng personality characteristic, or more specifically, as anxiety proneness. State Anxiety is defined by a short-lived anxiety, usually induced by an event or circumstance. Both of these indices of an xiety will be examined to differentiate the extent and level of anxiety.

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32 General Health-Related Quality of Life Short Form-12 (SF-12): This m easure was developed to gauge mental and physical functioning and can be separated into two comp onents: physical component summary (PCS-12) and mental component summary (MCS-12). All scores of the SF-12 are comparable and highly correlated with scores from the SF-36, from which it was derived, (ranging from .63-.97; Ware et al., 1995; Ware, Kosinski, & Kell er, 1996). The SF-12 reproduced 90% of the variance in the SF-36 PCS and MCS measures in th e United States and on cross-validation in the MOS (Ware et al., 1996). The Left Ventricular Dysfunction Questionnaire (LVD-36): This cardiac-specific measure was designed to assess the impact of le ft ventricular dysfuncti on on daily life and wellbeing. Responses are dichotomous (true or false). True responses are summed, which are then calculated as a percentage; highe r scores indicate worse func tioning (i.e., 0 = best possible score). The measure demonstrated high internal consistency in a sample with chronic left ventricular dysfunction (Kuder-Richardson coefficient = .95) (OL eary & Jones, 2000). Depression Beck Depression Inven tory-2nd Edition (BDI-II): The BDI-II is a 21-item self-report instrument assessing the presence and severity of depression symptoma tology over the preceding two weeks (Beck et al., 1996). Its internal consistency ranges fr om .91 to .93, its one-week testretest reliability is .93 and moderate to high co rrelations with other measures of depressive symptomatology supports its convergent validit y. BDI-II has been wide ly used in cardiac populations (Carney, Freedland, Sheline, & Weiss, 1997) and is the gold standard for assessing depressive symptoms in health-re lated populations (JAMA, 2000).

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33 Cognitive Screener Telephone Interview for Cognitive Status TICS: The TICS is a brief test of cognitive functioning developed. The TICS is similar to th e Mini-Mental Status Exam (Folstein, Folstein, & McHugh, 1975), but has a more comprehensive memory assessment, designed for identifying dementia. Potential participants with TICS sc ores of less than 30 were excluded from the study. Research has demonstrated that it is as reliable and valid as face-to-face administration. It has a sensitivity of 94% and specificity of 100% fo r distinguishing normal controls and demented individuals (Brandt et al ., 1988) and sensitivity of 82% and sp ecificity of 87% for distinguishing normal controls and amnestic mild cognitively impaired older adults (Cook, Marsiske, & McCoy, 2006). Reading The NAART (Blair & S preen, 1989; Nelson, 1982) was used to estimate overall reading abilities. Experimental Task The com puterized task was run on a DELL PC laptop computer using E-Prime software for stimulus presentation and behavioral data co llection. To ensure that participants understood task instructions and to increase familiarity with the button-press procedure, participants were pre-practiced on the computerized cognitive task. The task para digm utilized was a modified version of a classical dot-probe paradigm developed by Williams, Watts and McLeod (1988). Figure 2-1 illustrates a sample trial of the dot-probe task used in this experiment. The task comprised a briefly-presented word cue, shortly followed by a target to which participants made a speeded button-press response. Specifically, participants were instructed to focus on the center of the screen where they saw a fixation point. Each trial of the task began with a centrally-located 200-ms duration fixation point followed by a cue word presented to the

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34 top or bottom of the fixation cross. After 800 ms, the cue word was immediately replaced by a dot target, which appeared randomly in the same (congrue nt) or opposing (incongruent) location as the word. Participants were instructed to respond to the presentation of the target by pressing the h or j keys i ndicating the location of the dot as quickly and accurately as possible. The dot serving as a target disappeared after the key press or after 4000ms. The intertrial interval from the target offset to the next fixation cross was 1200ms. The participants response time (with ms accuracy; RTs) and accuracy to the target were recorded as dependent variables. Participants performed a tota l 240 experimental trials, equa lly and randomly distributed across four word types and two word positions. Each word was repeated four times during the entire task. Fifty percent of tr ials were congruent, drawing the at tention of the participant to the area where the word and asterisk appeared, whil e the remaining fifty percent of trials were incongruent, drawing participants attention to the area opposite the one where the asterisk appeared. Trials were randomized for each word category, with each category presented an equal number of times across the task. Four different word types were employed as cu es, including cardiac-specific threat words (e.g. shock, defibrillator, flutte r), non-cardiac-specific threaten ing words (e.g., fearful, scared, danger), pleasant words (e.g. delighted, confid ent, happy), and neutra l words (e.g. tile, doorknob, bland). Positive, threat and neutral words were chosen from norms of emotional words taken from the Affective Norms for English Words (ANEW; Bradley & Lang, 1999) and matched for frequency of usage in English, average word lengt h, and grammatical structure. Cardiac specific words were chosen from a group amassed and rated by clinicians at the Shands EP clinics and graduate students in the Card iac Psychology Lab. The cardiac-specific words were selected

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35 based on rating for high valence and arousal. Valence and arousal ratings were measured separately using a computerized administra tion of the Self-Assessment Manikin (SAM; Lang, 1980). Both dimensions of valence and arousal were rated on a 9-point Likert scale with 1=least pleasant/arousing and 9=most pleasant/arousing. Forty words comprised the final set of stimuli (Appendix A). As a manipulation check, participan ts performed valence and arousal ratings for each word seen in the experiment, using th e Self-Assessment Maniki n (SAM; Lang, 1980) after completion of the dot probe task.

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36 Table 2-1. Mean (+ standard deviation) demographic and ps ychological test data for VF and AF patients. Min/Max VF Patients (n=37) AF Patients (n=41) t-value Age (years) 34/80 62.36 (13.72) 63.12 (9.99) -.280 Education (years) 12/20 14.44 (2.41) 14.76 (2.35) -.572 TICS (raw score) 34/50 42.60 (4.45) 40.13 (3.23) .451 BDI (raw score) 0/11 6.85 (4.50) 5.34 (2.31) -.03 STAI-S (raw score) 20/62 32.48 (9.82) 34.25 (12.35) -.678 STAI-T (raw score) 24/56 37.77 (6.04) 34.05 (9.87) 1.29* LVD-36 (total score) 5.56/100 62.27 (25.99) 71.47 (27.65) -1.336 SF-12 {Physical} 17.06/57.66 34.94 (9.20) 40.58 (11.65) -2.321* SF-12 {Mental Health} 24.50/65.14 50.49 (10.41) 49.15 (10.58) .555 Note : TICS = Telephone Interview for Cognitive Status; BDI-II = Beck Depression Inventory; STAI-S = State Trait Anxiety Inve ntory state score; STAI-T = Stat e Trait Anxiety Inventory trait score ; LVD-36 = Left Ventricular Dysfunction Qu estionnaire *Groups significantly different at p <.05. Figure 2-1. Example of a typical incongr uent, clinically relevant trial.

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37 CHAPTER 3 DATA ANALYSIS AND RESULTS Data Analysis Dot Probe Task Dependant measures for the dot probe will in clude reaction times and error rates for each of the experimental conditions. For analyses i nvolving RT, we employed median RTs (Ratcliff, 1993) for correct responses. For analyses involvi ng error rates, data we re arcsine transformed (Neter, Wasserman, & Kutner, 1985) prior to all analyses. This transformation was used to normalize the distribution of the error data, which is often skewed because the error rates are so low proportionately. Median corr ect-trial reaction times (RTs) and arcsine errors were calculated for each participant and experimental condition, and subjected to separate Group x 2Cue Validity (Congruent, Incongruent) x 4-Cue Va lence (Pleasant, Neutral, General Threat, Cardiac Threat) Analyses of Variance (ANOVAs). Group served as the between-subjects factor, and cue congruency and cue valence served as within-subject factors. To correct for possible violations of sphericity, a Hyundt-felt epsilon adjustment was calculated where appropriate and adjusted p-values and unadjusted degrees of freed om are reported. Effect sizes for ANOVAS were measured using Eta squared. The followi ng hypotheses were addres sed in the analyses: Hypothesis 1: A main effect of congruency will be seen across groups (slower RTs and greater error rates to incongruent than congruent trials). Hypothesis 2 : ICD patients, compared to arrhythmia controls, will exhibit a specific and disproportionate RT slowing to incongruentrelative to congru ent-cue trials specifically involving clinically relevant words. Hypothesis 3 : There will be a significant 3-way in teraction, reflecti ng disproportionate slowing of ICD patients to clin ically specific incongruent vs. congruent cues compared to other word types and to AF controls.

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38 Reaction Time Data Overall, there was a signifi cant effect of congruency in the opposite direction than predicted, F (1, 78) = 16.377, p < .001, 2 = .98, with longer RTs to the congruent than incongruent condition. Th ere was no significant effect of valence, F (3,228) = .713, p>.55, 2 = .15, nor was there a Group x Valence interaction F (3,228) = .478, p>.67, 2 = .11. Finally, no Group x Congruency x Valence interact ion, was found as hypothesized for RTs F (3,228) = 1.857, p>0.14, 2 = .27 (Figure 3-1). Error Data A main effect of group was observed for error rates, F (1, 78) = 16.099, p < .001, 2 = .98, with ICD patients making greater errors overall, than AF patients. Next, we examined the effects of cue type (valence) on dot-pr obe task performance. There we re no significant effects of valence on error rates, F (3,228) = .684, p>0.55, 2 = .02, nor was there a Group x Valence interaction F (3,228) = .865, p>0.45, 2 = .01. Finally, no significant Group x Congruency x Valence interaction was found for error rates, F (3,78) = .781, p>0.50, 2 =.01 (Figure 3-2). Cue Word Valence and Arousal Ratings To determ ine if the words selected for the emotional manipulation in the dot probe task resulted in differential valence and arousal ra tings within and between groups, post-task SAM assessment valence and arousal ratings were an alyzed using separate ANOVAs; with group as a between-subjects factor and word category (Pleasant, Neutral, Unpleasant, Clinical) as a withinsubject factor. Results indicate that the words were, indeed, e ffective in producing th e desired effects: (1) Both arousal and valence ratings for the Pleasant, Neutral, and Unpleasant words were consistent with expectations, (2) the two gr oups did not differ in ratings of these standard words, (3) but VF patients rated the clinically-relevant words as signifi cantly more unpleasant th an AF controls.

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39 Cue Word Valence Ratings Analyses of valence ratings demons trated a main effect of valence, F (3,110) = 734.58, p<0.001, p < .001, 2 = .99. This main effect was quali fied by a significa nt Group x Valence interaction F (3,110) = 11.32, p<0.001, 2 = .92. Follow-up independent samples t-test revealed that ICD patients rated the clin ically-relevant words as significantly more unpleasant than AF patients, t (76) = 3.771, p<0.001; yet they did not diffe r in their rating of the other word categories (Figure 3-3). Cue Word Arousal Ratings Analyses of arousal ratings revealed a si gnificant m ain effect of word category, F (3, 110) = 274.29, p<0.001, 2 = .87. In general both groups rated pl easant, neutral and clinical words as more arousing than neutral words. No group by valence interaction was seen for arousal F (3, 110) = 3.07, p>.08, 2 = .12 suggesting that ICD and AF patients found the words, equally arousing despite a priori pr edictions (Figure 3-4). Effect of Shock on Dot Probe Task Shock and Reaction Time To exam ine the unique effects of shock on task performance, ICD recipients were grouped into shock and no shock categories. Fourteen ICD recipients received one or more shocks and 21 recipients had no hi story of shock. There were no significant effects of presence or absence of shock with respect to RTs, F (1,36) = 2.15, p>.53, 2 = .08. Additionally, no significant effect of valence F (3,102) =.774, p>.49, 2 = .13 or Shock x Valence interaction was found F (3,102) = 2.15, p>.09, 2 = .23. Finally, no Shock x Congruency x Valence interaction was found as hypothesized for RTs, F (3,102) = 1.288, p>0.33, 2 = .07 (Figure 3-5). Shock and Error Rates There were no significant eff ects of presence or absence of shock on error rates,

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40 F (1,36)= .57, p>.45, 2 = .08. Additionally, no signifi cant effect of valence F (3,102) =.1.037, p>.35, 2 = .02 or Shock x Valence interaction was found F (3,102) = .90, p>.96, 2 = .05. Finally, no Shock x Congruency x Valence interaction was found for errors, F (3,102) = 1.04, p>0.37, 2 = .02 (Figure 3-6). To further examine the impact of ICD shock on psychosocial measures of state, trait, and shock related anxiety, additional ANOVAs were run using only ICD shock as the group variable. No significant differences between groups were found for state anxiety, F (1,36)= .87, p>.35, 2 =.12, trait anxiety, F (1,36)= .28, p>.59, 2 = .15, and shock anxiety (FSAS), F (1,36)= .68, p>.41, 2 = .20. General attentional bias scores were calculated to qualitatively examine trends in the data by subtracting incongruent RT trials from congrue nt RT trials (Figure 3-7). While no significant differences emerged between groups (as discussed above); there was a patte rn of decreased bias to unpleasant and clinically-relev ant stimuli compared to pleasa nt and neutral stimuli. To examine the hypothesis that magnitude of bias was positively correlated with both ICD and AF patients an xiety levels, Pearson correlations we re calculated between bias scores and psychosocial measures of st ate, and trait anxiety. No sign ificant relationships emerged amongst bias scores and anxiety all ps > .05 Psychosocial Data Psychosocial m easures described in the methods were used to characterize the sample. ICD patients and AF controls were similar in their levels of psychological distress, such that they endorsed low levels of depression; similar levels of state anxiety, cardiac specific quality of life and general mental health (Table 2-1). Nota bly, ICD patients demonstr ated significantly more trait anxiety than AF controls t (78) = 1.29, p < .04, as well as worse phys ical health than AF

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41 controls t (78) = -2.321, p < .03. Additionally, when examining ICD patients alone, female recipients endorsed a greater level of shock related anxiety than male patients. Pearson correlations were calculated amongst psychosocial measures of anxiety. As expected, state anxiety was positivel y correlated with trait anxiety r (78) = .709, p < .01, suggesting, that AF and ICD pa tients who experience greater le vels of moment to moment anxiety are more likely to be generally anxious individuals. Additionally, because this study highlighted participants experience of livi ng with an ICD, state anxiety was positively correlated with shock related anxiety r (37) = .412, p < .01.

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42 400 500 600 700 800 900 1000Plea s ant N e utr al Unpleasan t C l i n ic al Plea sa nt N e utra l Unpleasant C l i ni c alVF AFReaction Time (msec) Congruent Incongruent Figure 3-1. Dot-probe task r eaction times for VF (ICD) a nd AF (control) patients. 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09P l e a s a nt Neutral Unp l easant C l inica l P leasa n t Ne u tr a l U np l ea s a nt C li n i c alVF AFProportion of Error s Congruent Incongruent Figure 3-2. Dot-probe task e rror rates for VF (ICD) and AF (control) patients. 1 2 3 4 5 6 7 8 9 PleasantNeutralUnpleasantClinical Word ValencePleasantness Rating VF AF Figure 3-3. Subjective ratings for cue-word valence.

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43 1 2 3 4 5 6 7 8 9 PleasantNeutralUnpleasantClinical Word ValenceArousal Rating VF AF Figure 3-4. Subjective ratings for cue-word arousal. 500 550 600 650 700 750 800 850 900P l eas ant N eutr al U n pl eas ant C l i ni cal Plea s ant Neu t ral Unpleasant Clinic alNo Shock Shock Reaction Time (msec) Congruent Incongruent Figure 3-5. Dot-probe task reac tion times for no shock (ICD) and shocked (ICD) patients. 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14Pleasan t N eutral Unpleasant Clin i cal P l e asan t Neutr a l U n ple as ant ClinicalNo Shock ShockProportion of Erro r Congruent Incongruent Figure 3-6. Dot-probe task e rror rates for no shock (ICD) and shocked (ICD) patients.

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44 -29 -28 -27 -26 -25 -24Pleasant Neutral Unpleasant Clinical Attentional Index Score (msec ) Valence Figure 3-7. Average attentional bias scores (incongruent-con gruent). Negative scores indicate decreased bias.

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45 CHAPTER 4 DISCUSSION Our study is the first to exam ine the relati onships between disease-related anxiety and attentional processing in patients living with IC Ds. While many studies have examined ICD and AF patient functioning from a biomedical perspective, evaluating symptoms, quality of life outcomes, and medical outcomes (Sears, 2004; S ears & Conti 2005; Godemann 2004.), this is the first examination of potential attentional bi as in this patient population. Four main findings emerged from the research: First, both ICD and AF patients showed a signifi cant attentional bias towards congruent information, irrespective of emo tional valence of the task word cue. Second and unexpectedly, ICD patients committed more errors overall than AF patients. Third, ICD patients demonstrated worse general physical f unctioning and greater tr ait anxiety as a group compared to AF patients. Contrary to predictions, however, the presence or absence of ICD shock did not distinguish this difference. Finally, ICD patient s found the clinically-relevant cue words more unpleasant than did AF patients. Evidence of Attentional Bias A prim ary aim of this study was to examine the ICD patients ability to disengage attention from shock-related (car diac specific) information using a modified dot-probe paradigm; that is, to determine if they exhibit evidence of a specific attentional bias towards clinicallyrelevant stimuli. The hypothesis was that IC D patients would be slower to respond to incongruent clinical trials comp ared to AF patients. Results demonstrated that regardless of group (ICD or AF control) or emotional valence of the words presented in the task, both groups were slower to respond to a probe presented at a congruent than incongruent location, suggesting a reverse congruency effect. This finding is novel and gene rally inconsistent with the literature on dot probe and Stroop tasks which consistently demons trate that subjects have longer

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46 reaction times under incongruent th an congruent conditions. The liter ature also demonstrates that emotional valence of the cue (e.g., word, picture, f ace) differentially affects a persons ability to respond to corresponding probes such that incongru ent trials with aff ectively arousing words, give rise to disproportionate ly slower responses. Although the finding that participants were slower to respond to a probe presented directly after an emotional word is surprising, past research has previously suggested similar inconsistencies, particularly in older populations. Fox and colleag ues (2005) demonstrated that older adults with high levels of state anxiety did not demonstrate a classical interference effect on an emotional Stroop task. In fact, their fi ndings demonstrated that older adults have a tendency to disregard the threat content of task relevant information and perform similarly on both congruent and incongruent tr ials. The findings from this study and another by Mather and Carstensen (2003) also suggest that older adults with low le vels of anxiety tend to avoid attending to negative emotional material. One explanation of the findings in this study is that age may have factored into the response style of participants. Our participants did not endorse clinically significant levels of st ate anxiety and were older than mo st cohorts in the classical dotprobe literature. As such, they may have disr egarded the emotional cont ent of the words during the task, focusing more on the directions asking them to respond to the probe. The reverse congruency effect in this task may be better understood through paradigms in the literature examining attentional engageme nt. Posner and colleagues (e.g. Posner, Cohen & Rafel, 1982) demonstrated the concept of atten tional engagement vs. disengagement to spatial location using a cued target paradigm. In this task, participants were instructed to focus on a fixation point between two rectan gles, wait for a cue (the bright ening of one rectangle) and respond to congruent or incongruent probes presented in one of the two rectangles. Participants

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47 in Posners experiment were fast er to respond to congruent than incongruent trials, suggesting an effect of cue dependency. In the paradigm used in this study, it is possible that cue word reading prior to a congruent probe response resulted in facilitated atten tion to that spatial location such that participants attended to the word and responde d to the probe in an automatic manner without paying conscious attention to the probe itself. Additionally, directing gaze towards a probe in the opposite location of the cue word (incongrue nt probe) may have required heightened disengagement of attentional resources (to make a correct probe response) such that participants could not dwell on the emotional content of th e word presented. Finally, the magnitude of attentional bias in this study wa s in the opposite direction demons trating decreased bias towards clinically-relevant and un pleasant words compared to neutral and pleasant words. This suggests that participants spent less time attending to the clinical words compared to the non-clinical words. While the result was not statistically si gnificant, it may provide further evidence for the reverse congruency effect. Cohort Effects on Task Contrary to expectations there was no effect of valence on task pe rformance. A potential explanation for this may be that participants were experiencing heightened arousal during the entire task and may have allocated all possible re sources to performing that task correctly at the expense of attending to the valence of the word s. Participants may have been over aroused throughout the task such that valence specific eff ects were washed out. Direct measurements of autonomic arousal (i.e., skin c onductance) (Lang et al. 2000) may have been useful in gaining information about physiological arousal in participants. Another notable finding in this study was that ICD patients exhibited greater levels of trait anxiety and worse self-repo rted physical functioning compared to AF controls. It is

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48 plausible that this increased gene ralized anxiety led ICD patients to make more errors in the dotprobe task compared to AF cont rols. Further support for this hypothesis is provided by the fact that there was no speed-accuracy trade off in ei ther group. ICD patients greater trait anxiety may also help to explain why no main effects of valence were found. Mogg and Bradley (1998) proposed that anxiety is the locu s of the individual differences in a persons threat appraisal mechanism. These researchers posit that high trai t-anxious individuals ap praise all levels of threat as subjectively greater than low trait-anxi ous individuals. As such, ICD patients in this sample may have reached a high level of threa t vigilance by viewing personally-threatening (clinical) words and subsequently appraised other valences as more unpleasant across the trials, suggesting the presence of a carryover effect. Differences in Methodology Another consideration given the general results of this study is the m ethodology employed to elicit evidence of emotional attentional bias. The traditional dot-probe task developed by McLeod and colleagues (1997) presen ted word pairs such th at spatial attention during the cue phase of the task was captured ac ross the screen with a different set of stimuli each time (e.g. a neutral word always accompanie d an emotional arousing word). On the traditional task, trials can be examined to deli neate preferences towards and away from threat related and neutral word pairs. The modified dot-probe task in this study was developed based on findings by Amir and colleagues (2004), who di d not employ the use of word pairs when examining attentional bias in so cial phobics. Thus, it is possible that the task employed in this study may not have been robust enough to elicit an attentional bias at the magnitude of other dotprobe tasks. Another methodological difference that potentially influenced the results in this study is the lack of a probability manipulati on (Amir et al., 2004, Fox et al., 2000). Other

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49 researchers have used a disproportio nately larger set of congruent tr ials verses incongruent trials, priming participants response pa tterns and increasing the magn itude of bias observed. Manipulation Check Finally, participants ratings of the valence and arousal of the cue words, dem onstrate a positive manipulation check. The ratings showed a disproportionate affective response to clinically-relevant stimuli in ICD patients, who rated the clinically-relevant (cardiac) words as more unpleasant compared to AF controls. One explanation of this findi ng is that the personal relevance of the clinical words was greater fo r the ICD patients than the AF patients. An example of a clinical word used in the task is shock. This word has clinical meaning for both groups. For ICD patients shock may refer to thei r device going off, and be a reminder to them that they have a life threateni ng arrhythmia. For AF patients s hock may refer to an external defibrillation treatment that helps to control th eir symptoms, potentially alleviating them. While the word is relevant to both groups, it has th e potential to connote gr eater negativity for ICD patients than AF patients. The pattern of findings suggest s that both groups were equally aroused by the word-cues irrespective of valence. Both the valence and arousal findings are novel and the first to be demonstrated in an arrhythmia population. Gi ven that both ICD and AF patients found the cardiac words highly arousing, it is possible that the words devel oped for this sample did not discriminate ICD related threat from AF related threat. Alternatively, the findings may suggest that recipients of ICDs and patie nts living with symptoms of AF are more similar with respect to levels of clinical hypervigilence than they are di fferent. This is further evidence that the sample in this study may have been too affectively homogenous to clearly elucidate the specific affective attentional bias hypotheses.

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50 Limitations The current study represented a fi rst step in the application of principles and paradigm s of cognitive neuroscience to the st udy of attentional pro cessing in ICD recipi ents. Additionally it offered a unique perspective in merging mechanis tic research with demonstrated psychosocial phenomena. Like many studies examining novel populations and paradigms, it ventured into uncharted territory and potential limitations must be addressed. A number of pragmatic and resource constraints may have affected the results. The first limitation of the pres ent study may have been with the study sample itself. The participants were highly selected and consisted mainly of Caucas ian, highly educated arrhythmia patients, which may not be representative of the general cardiac/arrhyt hmia population in the United States. In addition, string ent criteria were used to co ntrol for medical and emotional health. As such, the patients in this sample were psychologically healthier than similar samples described in the ICD literature (Sears, 2003; Goodeman, 2004; Kuhl, 2006). Given that most of our hypotheses were based on the prediction of hi gh anxiety, specifically shock-related anxiety, the lack of shock-specific anxiety in this c ohort may have affected the results obtained. Alternatively, it is possible that the ICD patients as well as AF controls were not anxious enough (given the low state/trait anxi ety scores for both groups) for ro bust group effects to emerge. Other similar studies have found individuals wi th higher STAI scores, specifically after experimental mood induction (Wilson & MacL eod, 2003; Fox et al, 2005) have biased attentional processing to emoti onally-relevant information. Another critical limitation that may have a ffected the ICD cohort in this study is the changing nature of the technology. More and mo re patients are being paced out of life threatening arrhythmias. That is, the ICD can detect an abnormally fast heart rhythm and as it prepares to fire, may terminate the rhythm befo re it becomes necessary to shock. The ICD group

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51 in this study had a low inciden ce of shock (63% had no shocks), as a result, they may not have been as anxious regarding their devices nor were they even familiar with post-shock psychological sequelae. Additiona lly, those who had been shocked at least once may have been educated about device acceptance and ICD shock and were therefore less concerned about the device. The ICD cohort at Shands hospital has been involved in numerous studies over the past 15 years specifically focusing on ICD education and device acceptance. Given the small number of clinics from which recruitment occurred, it is possible that oversam pling of this population affected their responses on familiar measures of psychosocial effects and device knowledge. Finally, the present study may have benefite d from a post-task ques tionnaire as well as post-task ratings of state, trait and shock-related anxiety. Qualitat ive feedback from participants regarding their subjective experi ence during the task may have aided in clarifying inherent cohort specific problems with the task (e.g. too easy, unclear etc) Post-task anxiety questionnaires would have offered a data point to examine whether the task itself induced anxiety in our patients. Future Directions Future studies may improve on the present methodology by employing a classic dotprobe paradigm which uses word pairs as cues (McLeod, Mathews, & Tata, 1986). Additionally, given the low levels of anxiety in this cohort, ICD related mood induction may prove useful in clarifying effects of device specif ic anxiety on attentional bias. Mood induction is widely used in studies examining affective processing and is a powerful tool to i nduce an affective state (Compton, 2003). Use of the startle paradigm (e .g. eye-blink reflex) may provide more direct measurement of heightened threat relevant arous al and vigilance in arrhythmia patients. Additionally, direct measures of physiological arousal such as skin conductance, heart rate, and blood pressure may also be useful in characteri zing and differentiating VF and AF patients.

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52 APPENDIX WORD STIMULI USED IN TASK Table A-1. Word stimuli used in task Pleasant Neutral Threat (noncardiac) Cardiac Threat Fame Align Agitate Shock Grin Mascot Bully Defibrillate Sunrise Logic Ruin Flutter Delight Depot Curse Fatal Brave Perform Avenge Palpitations Bold Panel Damage Dizzy Affection Prompt Insult Faint Cheer Review Hurt Racing Cute Knit Horrify Heartbeat Kitten Invent Loathe Pain

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59 BIOGRAPHICAL SKETCH Neha Dixit graduated from the Mount Holyoke College with a bachelors degree in Neuroscience and Behavior. She then spent 2 ye ars working as a research associate at the National Institutes of Mental Health, in the Clin ical Brain Disorders Branch. Ms. Dixit earned a masters degree in clinical and health psychology at the Univers ity of Florida in 2003 and then began her doctoral studies in the same program She concluded her docto ral training with an internship at the James A. Haley Veterans Medical Center in Tampa, FL. After internship, Ms. Dixit plans on pursuing a neur opsychology post-doctoral position.