Exercise training and cardiac rehabilitation in patients with implantable cardioverter defibrillators: a review of current literature focusing on safety, effects of exercise training, and the psychological impact of programme participation

Background: Indications for implantable cardioverter defibrillators (ICDs) have been widened considerably during the last decade due to the well-documented effect in the heart failure population. Exercise training (ET) has a 1A recommendation in heart failure. However, data on safety and efficacy of ET in patients with ICDs is sparse. ICD shocks are associated with reduced quality of life and increased mortality. Whether ET may have a beneficial effect in heart failure patients with an ICD is not well documented. Methods: This review is based on a systematic search in the Pub Med database using the terms 'exercise training', 'implantable cardioverter defibrillator', and 'cardiac rehabilitation'. Results: Nine studies were identified, comprising 1889 patients. The average duration of exercise-based cardiac rehabilitation (CR) was 9.6 weeks. Ten ICD therapies (seven shocks) were reported in the 834 patients with ICD during ET. Between exercise sessions and during follow up 182 events were recorded including 166 shocks. Three studies (2 randomized) showed that the control group representing sedentary patients were more prone to ICD discharge than patients undergoing CR/ET. In all studies the ICD patients improved their aerobic fitness following ET. Few studies report data on the effect of ET on anxiety and depression. Conclusion: Based on the current literature, ET in patients with an ICD seems to be safe and is not associated with increased risk of shocks. ET improves aerobic capacity in ICD patients, while effects on anxiety, depression and quality of life are still under debate.