Issues in cardiovascular nursingAvoidance behaviors in patients with implantable cardioverter defibrillators
Introduction
The implantable cardioverter defibrillator (ICD) has gained acceptance as the best therapy for many types of malignant cardiac arrhythmias.1 However, the shock, although therapeutically effective, may be perceived as highly aversive by patients. Anxiety and vigilant monitoring of physical symptoms are common among patients with ICDs.2, 3, 4, 5 Estimates of anxiety related to ICD shock among patients vary, with some studies reporting more than 50% of patients experiencing such anxiety,4, 6 and 1 study reporting that 35% of patients with ICDs described anxiety related to possible shock as the most distressing aspect of the device.7
Godemann et al2 examined the incidence of panic disorders and agoraphobia among 69 patients after ICD implantation. Forty-eight patients (70%) experienced shocks during the follow-up period. Of the sample, 16% experienced agoraphobia or panic disorder after ICD implantation, and a further 14% showed dysfunctional avoidance that did not quite meet the criteria for a panic disorder or agoraphobia. Those who met the criteria for anxiety disorder had significantly higher fear of ICD shock and continuously monitored their physical symptoms for signs of an impending shock. The authors concluded that patients with ICDs represent a high-risk population for experiencing panic disorders and agoraphobia and are therefore suitable for prospective studies.
It has been widely asserted that classical conditioning plays a role in the development of panic disorder and agoraphobia.8 According to the classical conditioning model, an aversive stimulus will condition avoidance or escape responses to stimuli that occur in temporal proximity to it.9 Subsequent exposure to the co-occurring stimuli will typically generate some level of avoidance, despite the absence of the aversive event. Avoidance results in a reduction of anxiety, therefore maintaining the conditioning through a process of negative reinforcement.10 Studies of anxiety in ICD recipients suggest that inappropriate avoidance responses might be conditioned in some patients.2
A further possible explanation for avoidance behavior among patients with ICDs is offered by the cognitive model of anxiety.11 According to this model, individuals who are prone to anxiety have exaggerated perceptions of threat and use avoidance behavior as a way of protecting themselves from perceived danger.11 Avoidance is counterproductive because it prevents disconfirmation of a perceived threat. In the case of patients with ICDs, those who are prone to anxiety would be more likely to avoid situations and activities that are perceived as threatening.
An alternative cognitive model based on panic disorder12 hypothesizes that certain vulnerable individuals are hypervigilant to their own body symptoms and are prone to making catastrophic negative interpretations in response to symptoms such as a rapid or more pronounced heart rate. These negative interpretations cause an increase in anxiety and physical arousal, which in turn cause an increase in the severity of their symptoms through a process known as “positive feedback.” Places where having an anxiety attack would be embarrassing or difficult to escape (eg, shopping center and public transport) are most frequently avoided.12 In the case of ICD recipients, the fear of physical symptoms and the possibility of receiving a shock would reinforce avoidance of activities such as exercise, because the physical symptoms (eg, elevated heart rate) would be perceived as dangerous. Patients would also be expected to avoid places where having a shock would be inconvenient or embarrassing.
The relative contribution of conditioning and cognitive factors to avoidance in patients with ICDs is not known. Pauli et al4 found that ICD recipients with anxiety related to future shocks exhibited scores that were comparable with those of patients with panic disorders on a range of psychological measures, including anxiety sensations, trait anxiety, catastrophizing cognitions, and agoraphobic avoidance. However, they found no associations between patients' shock experiences and associated levels of anxiety. As a result, they concluded that their data do not support simple conditioning models of anxiety among ICD recipients and suggested that the cognitive model offers the most straightforward explanation of their findings.
Studying avoidance among recipients of ICDs may not be straighforward. Many patients are older and often in poor health. They may already display considerable avoidance toward some apparently innocuous activities for psychological or physical reasons (eg, fear of falling). In addition, there are a number of objects that these patients are advised to avoid, particularly those generating strong electromagnetic fields, which can result in nontherapeutic shocks or even disabling of the ICD. Therefore, when examining avoidance among ICD recipients it is essential to control for these factors by distinguishing recommended from unrecommended avoidance.
We report the outcome of a brief survey on avoidance behaviors among ICD recipients and examine whether particular classes of stimuli are preferentially involved in the establishment and maintenance of inappropriate avoidance behaviors. In addition, we examine the relevance of the classical conditioning versus cognitive models of anxiety as possible explanations for inappropriate avoidance within this group.
Section snippets
Subjects
A total of 143 of 256 recipients of ICDs who were listed in the patient database of the Cardiac Rehabilitation Education Program at the Royal North Shore Hospital, St Leonards, NSW, Australia, participated in the study.
Instruments
An anonymous questionnaire was developed for the purpose of this study (Appendix). In addition to demographic information, the questionnaire included questions regarding whether and to what extent respondents had begun avoiding places, objects, and activities since receiving an
Results
A total of 143 questionnaires were returned. Five of the potential respondents had died, and another 9 could not be contacted, resulting in a response rate of 58%. Respondents included 30 women, 109 men, and 4 of unspecified sex. Their mean age was 66.9 years (range 28-85 years) with 2 respondents failing to report their age. Men were older than women, had their ICDs implanted for a longer period, and reported having more shocks (Table I). However, there were no significant differences between
Discussion
Although the sample size was reasonably large, the response rate of 58% suggests that the data need to be interpreted with caution. Because the survey was anonymous, it was not possible for us to follow up nonrespondents to identify any possible bias in the sample.
We had initially attempted to locate a validated instrument to evaluate avoidance behavior with this cohort; however, no suitable measure could be found. Consequently, the survey was developed to provide a structured method of
References (18)
A cognitive model of panic
Behav Res Ther
(1986)- et al.
Help seeking in a support group for recipients of implantable cardioverter defibrillators and their support persons
Heart Lung
(2000) - et al.
Technologic advances in implantable cardioverter defibrillators
Curr Opin Cardiol
(1999) - et al.
Classic conditioning and dysfunctional cognitions in patients with panic disorder and agoraphobia treated with an implantable cardioverter/defibrillator
Psychosom Med
(2001) - et al.
Psychosocial outcome after ICD implantationa current perspective
Pacing Clin Electrophysiol
(1998) - et al.
Anxiety in patients with an automatic implantable cardioverter defibrillatorwhat differentiates them from panic patients?
Psychosom Med
(1999) - Pycha C, Calabrese JR. Good psychosocial adaptation to implantable cardioverter defibrillators. In: Willner AE,...
- et al.
Akzeptanz und lebensqualität nach implantation eines automatischen kardioverters/defibrillator
Z Kardiol
(1994) - et al.
Patient acceptance of the implantable cardioverter defibrillator in ventricular tachyarrhythmias
Pacing Clin Electrophysiol
(1993)