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Sudden death in dilated cardiomyopathy
1Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109, USA.
Insights
Sudden death in dilated cardiomyopathy (DCM) is often caused by ventricular arrhythmias. While ACE inhibitors improve survival, the roles of newer drugs and devices for arrhythmias in DCM require further investigation.
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Background:
- Dilated cardiomyopathy (DCM) is a significant cause of heart failure and sudden cardiac death.
- Arrhythmias, particularly ventricular arrhythmias, are a major contributor to mortality in DCM patients.
Purpose of the Study:
- To review the role of arrhythmias in sudden death among patients with dilated cardiomyopathy.
- To discuss current and emerging treatment strategies for managing arrhythmias in DCM.
Main Methods:
- Comprehensive literature search of MEDLINE database (1985-present) and relevant article citations.
- Analysis of studies on the pathophysiology, prognostic significance, and management of arrhythmias in DCM.
Main Results:
- Ventricular arrhythmias are the primary cause of sudden death in DCM, with ventricular ectopy potentially indicating risk.
- Autonomic nervous system and renin-angiotensin-aldosterone axis abnormalities contribute to ventricular arrhythmias.
- Electrophysiologic studies and signal-averaged electrocardiography have uncertain roles in risk stratification.
Conclusions:
- Ventricular tachyarrhythmia is the main pathophysiological mechanism for sudden death in DCM.
- Angiotensin-converting enzyme inhibitors are crucial for improving overall mortality.
- Ongoing research is evaluating amiodarone, angiotensin-receptor antagonists, beta-blockers, and implantable cardioverter-defibrillators for arrhythmia management in DCM.
Abstract:
The purpose of this review is to examine the potential contribution of arrhythmia to the occurrence of sudden death in dilated cardiomyopathy (DCM) and to discuss current treatment options. We performed a search of the MEDLINE database from 1985 to the present and the reference citations of selected articles pertaining to the prognostic significance, management, and pathophysiology of arrhythmias in DCM. A large proportion of patients with DCM die suddenly, most secondary to ventricular arrhythmia and a smaller proportion due to bradyarrhythmia. The presence and severity of ventricular ectopy may predict risk for sudden death, but the role of electrophysiologic study and signal-averaged electrocardiography in further risk stratifying patients remains uncertain. Abnormalities of the autonomic nervous system and renin-angiotensin-aldosterone axis appear to promote the occurrence of ventricular arrhythmias. Angiotensin-converting enzyme inhibitors improve overall mortality in congestive heart failure, and the use of direct angiotensin-receptor antagonists is currently being studied. In addition, beta-receptor antagonists appear to improve morbidity and may prove to improve mortality in heart failure as well. Other interventions still under investigation include amiodarone and the implantable cardioverter-defibrillator. The underlying pathophysiology of sudden death in DCM involves primarily ventricular tachyarrhythmia. Angiotensin-converting enzyme inhibitors remain a mainstay of improving overall mortality, while further study on the roles for newer drugs and devices is ongoing.