Clear and convincing clinical evidence has established that living with an implantable cardioverter-defibrillator (ICD) saves patients’ lives. In a 1999 landmark trial comparing the ICD to anti-arrhythmic drugs, the “ICD remains superior in prolonging survival after life-threatening arrhythmia.” Concomitantly, psychosocial research on the ICD has shown that living with the device as a treatment for life-threatening arrhythmias can lead to further/increased anxiety, isolation, hostility, and depression. The typical ICD recipient must overcome both the stress of life-threatening arrhythmias and the challenge of adjusting to the device, with 13% to 46% of patients experiencing anxiety symptoms and 24% to 46% of patients experiencing depressive symptoms. Clinical trials have demonstrated that psychological stress can have deleterious effects on the heart. Psychological stress has been shown to be a risk factor following myocardial infarction for ischemic complications, re-infarction, mortality, and in-hospital complications. Psychological stress adversely affects cardiac risk-factors and disease states, including the equilibrium of the autonomic nervous system and vagal control, which leads to increased incidence of significant ventricular tachyarrhythmia. Aberrations in autonomic cardiovascular regulation, such as impaired baroreflex response and decreased heart rate variability, also have been shown to be independent risk factors for sudden cardiac death. Further, distressing emotional states, which can increase cardiac repolarization instability, precipitate life-threatening ventricular arrhythmias in ICD patients. While the specific mechanisms of how psychological stress adversely affects the heart are not clearly known, “possible causes include heightened activation of the sympathetic nervous system, diminished parasympathetic activity, alternations in coagulation and fibrinolysis, and reduced compliance with treatment programs.”
Clinical trials have also shown yoga to be effective in addressing both psychological and physical components that are present in illnesses such as cardiovascular diseases. These include cardiovagal function, sympathetic activation, oxidative stress, coagulation profiles, and symptoms of anxiety and depression. Research using yogic breathing techniques in patients with arrhythmias has shown a significant reduction in the indices of ventricular repolarization dispersion.
Participation in yoga may be particularly beneficial for ICD patients in addressing the psychological and physical rigors of living with cardiac disease and an ICD. Despite a seemingly good fit between patient symptomatology and the mind-body techniques of yoga, no published studies that evaluated yoga as a treatment for psychosocial distress in ICD recipients were found in the biomedical literature.
Findings of the research study
The results of this investigation suggest that the yoga intervention was an effective treatment for reducing shock anxiety, for increasing self-compassion, and for reducing the number of DTV events for ICD recipients. This is consistent with research by Lampert, et al., which has shown that psychological factors can be associated with arrhythmias requiring ICD termination. Statistically, the reduction in shock anxiety and increase in self-compassion in the intervention group were significant, and the benefits appear to be attributable to the intervention. While the yoga group improved on shock anxiety and self-compassion, the control group experienced the opposite. The yoga intervention group also experienced an increased sense of equanimity or mindfulness, which is a core tenet of yoga. These outcomes in the yoga intervention group are noteworthy, given the level of anxiety that is present in the ICD population generally, and the fact that ICDs are considered the best treatment for cardiac arrhythmias. In fact, research results published while this study was underway found that “anxiety seems to be more prevalent in cardioverter–defibrillator patients than depression, with prevalence rates of anxiety reported from 24–87% compared to 24–33% for depressive symptoms.”
Another recent study indicated that diseases specific anxiety were independently important in that it predicts poor perceived health outcomes differently than general anxiety measures in ICD recipients: it was particularly associated with feelings of disability and cardiopulmonary complaints. These new findings corroborate the deleterious effects that ICD-specific anxiety may have on recipients, both mentally and physically, making the findings of this investigation even more relevant as a possible way to reduce morbidity and mortality in the ICD population.
This study suggests yoga was particularly valuable in aiding ICD-specific adjustment. The most intriguing and encouraging cardiac finding related to the yoga intervention group was the multiple regression model predicting fewer DTV events for the intervention group than the control group. Poole, Johnson, and Hellkamp, et al. concluded in their clinical study that “among patients with heart failure in whom an ICD is implanted for primary prevention, those who receive shocks for any arrhythmia have a substantially higher risk of death than similar patients who do not receive such shocks.” Additionally, once shocked, patients have a higher risk of late non-sudden cardiac death. Because DTV events are triggered by pro-arrhythmic states, they are a likely indicator of the severity of underlying heart disease. The results of our study suggest that yoga intervention may have a role in mitigating the severity of the participants’ arrhythmic conditions. Participants in the yoga intervention were more likely to maintain physical activity because they reported less concern that their behaviours would trigger device firing, allowing them to progress in their recovery. The control group was more likely to report functional impairment and anxiety about physical ailments.
The results demonstrate psychological benefits from a program of adapted yoga, compared to usual care, for ICD recipients, who are at risk for developing elevated levels of psychological stress, accompanied by increased risk for morbidity and mortality. Marked improvements were reported in total shock anxiety, self-compassion, and equanimity. Yoga participants’ overall shock anxiety decreased while the control group’s increased. The yoga group also had greater overall self-compassion, greater equanimity, and a 32% lower risk, relative to the control group, of experiencing device-related firings at the end of the study.
To wit, the participants in the yoga intervention were less likely to require action from the ICD to regulate heart function. The results of this study demonstrate both cardiac and psychosocial improvements from a yoga intervention for ICD patients.