It has been long acknowledged that electrical-conduction disturbances may be both a cause of heart failure and a consequence of it. In fact, many patients with heart failure have an asynchronous contraction pattern of the heart muscle that further reduces the heart ability to pump blood. Electrical disturbances may therefore result in progressive left ventricular dysfunction, due to the added effects of HF-related electrical dyssynchrony. For this reason, device therapy may play a key role in the management of patients with heart failure and reduced ejection fraction (HFrEF). In particular, Implantable Cardioverter- Defibrillators (ICD) and Cardiac Resynchronization Therapy (CRT) may improve ejection fraction by reestablishing mechanical synchrony, possibly reversing symptoms and signs of heart failure, in addition to the more obvious role of ICD in terminating ventricular arrhythmias that threaten sudden death. Recommendations on device therapy from the current guidelines on heart failure management put out by the ESC/HFA in 2016 update our understanding of the evidence base for the use of ICD and CRT in HFrEF. We review these recommendations and the evidence behind them.
Effects of exercise training on physical activity in heart failure patients treated with cardiac resynchronization therapy devices or implantable cardioverter defibrillators
