Aims Cardiac resynchronization therapy (CRT) has been shown in several clinical trials to improve symptoms and exercise capacity in patients with advanced heart failure. The first clinical trials of CRT-D devices were based on populations who already met a standard indication for implantable cardioverter defibrillator (ICD) therapy. In these patients, when CRT is contemplated, a CRT-D device is used. In a broad population of patients with advanced heart failure, the choice of adding ICD therapy is less clear. Methods and results Results of several clinical trials of CRT and ICD use in heart failure are reviewed. An analysis of data suggests that CRT may reduce death due to progressive heart failure. Recently, the COMPANION trial has reported that CRT can reduce long-term morbidity and mortality. CRT can be delivered as a pacemaker only, or in combination with an ICD. Taken alone, an ICD can improve survival in select groups of patients with left ventricular dysfunction; however, adverse effects have been seen, such as worsening heart failure. Conclusion There are no clinical trials designed specifically to address the relative merits of CRT delivered by pacemaker versus ICD. Based on our knowledge of the effects of both, along with data from recent clinical trials, it appears as though the preponderance of evidence is in favor of CRT-D. More will be learned from clinical trials currently underway.
All Science Journal Classification (ASJC) codes
- Cardiology and Cardiovascular Medicine