Sudden cardiac death in dilated cardiomyopathy -- therapeutic options

Despite routine use of angiotensin-converting enzyme (ACE) inhibitors, beta-blockers and spironolactone in patients with heart failure due to dilated cardiomyopathy (DCM), these patients still have a considerable annual mortality rate of 5-10%. Sudden unexpected death accounts for up to 50% of all deaths and is most often due to rapid ventricular tachycardia or ventricular fibrillation and less often due to bradyarrhythmias or asystole.

The use of beta-blockers in patients with heart failure has been shown to improve overall mortality considerably. This survival benefit has been demonstrated for bisoprolol, metoprolol and carvedilol. Therefore, one of these three beta-blocking agents should be administered routinely starting with low doses in all patients with New York Heart Association (NYHA) class II or III heart failure in addition to ACE inhibitors, unless there is a contraindication to beta-blocker use. In addition, NYHA class IV heart failure patients have been shown to benefit from carvedilol therapy, if tolerated. The conflicting results of GESICA and CHF-STAT studies do not support a strategy of "prophylactic" amiodarone therapy in patients with DCM in order to prevent sudden cardiac death. Despite growing evidence that implantable cardioverter defibrillator (ICD) therapy results in improved overall survival py preventing sudden cardiac death in patients at high risk for serious arrhythmic events, arrhythmia risk stratification with regard to prophylactic ICD implantation remains highly controversial in patients with DCM.

This review describes potential arrhythmia mechanisms in DCM and summarizes the results of antiarrhythmic drug trials and of prophylactic ICD trials in patients with heart failure as well as our knowledge concerning arrhythmia risk stratification in patients with DCM.