Shock as a Determinant of Poor Patient‐Centered Outcomes in Implantable Cardioverter Defibrillator Patients: Is There More to It Than Meets the Eye?

Abstract

The medical benefits of the implantable cardioverter defibrillator (ICD) are well established, but ICD shocks are known to influence patient-centered outcomes. In this viewpoint, we examine the strength of the evidence as found in primary and secondary prevention trials that used quality of life as an outcome, and compare the influence of ICD shock with other factors (e.g., heart failure and psychological factors) as determinants of outcomes, with a view to providing recommendations for clinical practice and future research. Based on the large-scale primary and secondary prevention trials (i.e., CABG-PATCH, CIDS, AVID, AMIOVIRT, SCD-HeFT, MADIT-II, and DEFINITE), evidence for an association between ICD shocks and quality of life is mixed, with some indication that the influence of shocks may depend largely on the interval between shocks and assessment of quality of life. In order to improve the clinical management of ICD patients, we need to adopt a more rigorous and standardized methodology in future studies in order to be able to draw firm conclusions about the impact of ICD shocks on individual patients. We also need to acknowledge that the impact of shocks on psychological functioning and quality of life may not be as straightforward as previously assumed. Given that programming of the ICD is changing, leading to fewer shocks and improved quality of life, it may be timely to also examine the influence of other determinants (e.g., heart failure progression and the patient's psychological profile) of patient-centered outcomes both in research and in clinical practice.

Posttraumatic Stress and the Implantable Cardioverter-Defibrillator Patient

“…The effect of cardiac condition and the experience of shock varies from patient to patient and may not be as straightfor- ward as previously presumed. 5 Although some have suggested that there is little decrement to QoL after a single shock, debate exists as to whether it is premature to make conclusions regarding the effects of ICD shock. Especially given that the existing data are drawn from large, randomized, controlled trials predominantly using generic QoL measures that might not be as sensitive to detect the specific effects of shock.…”

“…Finally, personality characteristics associated with negative emotional processes and social inhibition (type D personality) have also been established as prevalent (24%) in ICD patients and linked to increased risk of ventricular arrhythmia (hazard ratio, 1.89) and mortality (hazard ratio, 2:79). 5 Taken together, sufficient evidence exists to warrant the inclusion of psychosocial factors in the routine treatment planning of ICD patients.…”

“…4 Shock has been a primary focus in this work because of its potentially traumatic impact on the patient experience. Although there is mixed evidence on the effect of single ICD shocks, 5,6 the literature consistently supports the negative impact of Ͼ5 shocks on quality of life and emotional distress. 7,8 ICD shock has been a focus of research interest because it is a unique experience for the ICD patient and can be perceived as a traumatic event.…”

Managing With Pacemakers and Implantable Cardioverter Defibrillators

“…In studies that evaluated the effects of both shocks and psychosocial factors, some have found that psychosocial factors, such as underlying personality traits, play a larger role than shocks in determining QOL for ICD patients. 15 Thus, it is likely that shocks interact with psychosocial factors such as personality traits and social support in influencing QOL for patients with ICDs.…”

“…As with QOL, it is likely that many factors, such as baseline psychological traits and social support, interact with shock to impact whether patients develop anxiety, depression, or posttraumatic stress disorder. 7,15 Interventions to Improve Psychosocial Outcomes…”