Dealing with the Unintended Consequences of ICD Therapy

Deborah Gamperling, MSCP, and Christian Machado, MD, Director of Cardiac Electrophysiology and Cardiac Rhythm Management Device Clinic Providence Hospital & Medical Center Southfield, Michigan
Deborah Gamperling, MSCP, and Christian Machado, MD, Director of Cardiac Electrophysiology and Cardiac Rhythm Management Device Clinic Providence Hospital & Medical Center Southfield, Michigan

While the efficacy of implantable cardioverter-defibrillators (ICDs)1-3 and biventricular ICDs4 is well established, the concept of unintended consequences is often overlooked. For patients who meet the criteria to receive these devices, the need to have such a device implanted can provoke feelings of anxiety and fear, and the presence of the device after implantation can serve as a continuous reminder of their higher risk status. In the case of ICDs, the burden of carrying a diagnosis related to a low ejection fraction and an elevated risk of experiencing a lethal dysrhythmia can weigh heavily upon the mind of a person who has been statistically identified as being at risk, but has no other readily observable signs or symptoms of cardiac disease. When ICDs were first available for implantation, most candidates were cardiac arrest survivors or those who presented with scar-related ventricular tachycardias. Upon arrival at the hospital, an electrophysiology study would be scheduled, and induced arrhythmias would be treated with a succession of anti-arrhythmic medications. If the medications failed to successfully terminate the arrhythmia, the patient would then be scheduled to receive a device. The process often took several days to complete, and the dire potential consequences of foregoing the device were all too clear to both the patient and the family. 

As studies such as the MUSTT trial, SCD-HeFT, and the succession of MADIT trials enhanced the understanding of cardiac risk factors for sudden death, the number of eligible candidates for devices has grown significantly and the goal of therapy has shifted from rescue, in the event of subsequent arrests, to primary prevention of events. The population of patients with an indication for an ICD today is often younger and healthier than those in the past. This shift in patient demographics may also contribute to a greater degree of dissatisfaction with the device as well as less acceptance of the indication for it, in the absence of a self-perception that incorporates an elevated risk for sudden cardiac death. 

A diagnosis that implies a life-threatening situation that is also chronic, and which can be treated but not cured, is also likely to induce anxiety and other negative emotions in those receiving the diagnosis as well as for their family members. Being able to offer treatment options is important, and the continuous development of ever-more sophisticated devices provides additional and better solutions for patients in need of treatment. Those in the EP field who have witnessed the improvements in the technology over the years can attest to the number of lives that have been saved and the reduction in morbidity for out-of-hospital cardiac arrests. The cascade of technology continues, but the difficult emotions experienced by the patients involved in these events have remained relatively unexamined and, sometimes, unacknowledged.

The data on the degree of anxiety experienced by patients with ICDs varies widely, between 24% to 87%.5 The prevalence of depression in ICD patients can range up to 46%.6 However, depression is not and should not be considered a normal response to any form of cardiac disease. Depression doubles the risk of sudden cardiac death among healthy individuals, and the threat is even greater for those with cardiac conditions.7 The well-known phenomenon of “phantom” shocks may be one way in which the underlying distress finds expression. Patients who have experienced device shocks, whether appropriate or inappropriate, often make unconscious associations between the activity that occurred just prior to the shock and the occurrence of the shock itself, assuming that the two events are related. Consequently, they will avoid those activities in the hope that another shock may be prevented, thus reducing normal behaviors and potentially limiting their quality of life. If, coincidently, additional shocks are not forthcoming, the erroneous beliefs are reinforced, and activities may be further cut back.

The ability of the contemporary ICD to identify and rapidly terminate a potentially lethal arrhythmia, while lifesaving in operation, may also overwhelm and frighten a patient who remains fully conscious and cognizant of the dramatic event taking place. He or she is no longer a statistical probability, but has now become dependent upon the implanted technology that maintains his or her life, and must acknowledge that reality. A virtual Pandora’s Box of potential psychological issues can open and may play out in various forms. For some, the dependency needs will evoke concerns about how well the device will function and what may happen in the event of a malfunction; such concerns can be exacerbated when there are notifications of advisories and/or recalls related to aspects of device function and system component failures. For others, a sense of loss of control and autonomy may contribute to a pre-existing tendency to experience anxiety and other negative effects.

In the event of multiple shocks or “electrical storms,” patients can become traumatized by repeated shocks, and experience feelings of fear and helplessness. Worries about continued events can lead to intrusive thoughts and recurring dreams, with symptoms of increased arousal, avoidance and emotional numbing that, over time, may develop into a form of post-traumatic stress disorder. In such situations, the implanted device can serve as an unavoidable, constant reminder of past events and potential future events, and can reinforce a sense of learned helplessness.

There is considerable evidence that emotional distress can alter the cycle length of ventricular arrhythmias, which can facilitate more lethal variations and render them more difficult to terminate.8 Mood disturbance has been demonstrated to be an independent predictor of arrhythmic events monitored by an ICD, even when controlling for the influences of heart failure, antiarrhythmic medications and history of coronary artery disease.9 Electrophysiologists have strived over time to reduce or eliminate the pain patients experience when devices deliver therapy by improving programming, adding tiered therapy with anti-tachycardia paced termination algorithms and other refinements; however, the mental distress experienced by some patients may be actively working against these efforts. 

With the demands of busy device clinics and complicated procedures in the EP labs, electrophysiologists can sometimes have limited time to discuss the emotional sequelae of having an implanted device, or to provide the support needed for an adequate adjustment to a new self-perception. ICD patients, already struggling with issues of dependency, may be reluctant to express their emotional concerns to busy members of the medical staff, feeling that they must cope on their own. ICD support groups can reduce feelings of isolation and provide valuable opportunities for mutual support as well as a venue for expression of common concerns. However, for some patients, support group activities may not be sufficient to alleviate the burden of emotional distress related to living with their device. Deeply ingrained patterns of responding to life challenges can contribute to an inability to make the adaptive changes needed to fully integrate the new reality of their health status. In such situations, it would be worthwhile to consider adding a staff member to the electrophysiology team who is able to provide appropriate psychotherapy to these patients. 

As discussed here, there are several unintended consequences of ICD therapy. Addressing the underlying issues of emotional distress experienced by these patients can truly enhance the comprehensive care centers are able to provide, and improve the quality of life for patients with implantable devices. 


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