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Effect of antiarrhythmic therapy on mortality after myocardial infarction
D Burckhardt1, A Hoffmann, W Kiowski
1Division of Cardiology, University Hospital Basel, Switzerland.
Insights
Beta-blockers significantly reduce sudden death in coronary artery disease patients. Low-dose amiodarone is a viable alternative for those with contraindications, especially with impaired left ventricular function.
Area of Science:
- Cardiology
- Pharmacology
- Clinical Trials
Background:
- Coronary artery disease (CAD) patients with ventricular ectopic activity face increased mortality risk.
- Previous studies on Type I antiarrhythmic agents showed adverse effects.
- Beta-blockers have demonstrated efficacy in secondary prevention trials for CAD.
Purpose of the Study:
- To evaluate antiarrhythmic drug efficacy in improving survival for CAD patients with high-grade ventricular ectopic activity.
- To compare the effectiveness of different antiarrhythmic drug classes.
Main Methods:
- Meta-analysis of randomized controlled trials (RCTs) for Type I antiarrhythmic agents.
- Pooled analysis of secondary prevention trials using beta-blockers.
- Prospective, controlled, randomized trial (BASE trial) using low-dose amiodarone.
Main Results:
- Type I antiarrhythmic agents were more likely to be detrimental than beneficial.
- Beta-blockers reduced sudden death rate by 24% in CAD patients.
- Low-dose amiodarone reduced sudden death by 60% and arrhythmic events by 74% in the first year post-myocardial infarction.
Conclusions:
- Beta-blockers without intrinsic sympathomimetic activity are advisable for CAD patients with ventricular ectopic activity and adequate left ventricular function.
- Low-dose amiodarone is a crucial alternative for patients with contraindications to beta-blockers, including impaired left ventricular function.
Abstract:
In an attempt to improve survival of patients with coronary artery disease and high-grade ventricular ectopic activity, several studies using different antiarrhythmic drugs were undertaken. A meta-analysis of all randomized controlled trials using type I antiarrhythmic agents showed that the treatment effect was much more likely to be adverse than beneficial. In contrast to these studies, the pooled results of major secondary prevention trials using beta-blocking agents could demonstrate a significant reduction in the sudden death rate by an average of 24% during observation periods of 9-36 months. In the beta-blocker trials, however, patients with contraindications for this type of drug, such as overt congestive heart failure or chronic obstructive lung disease, were excluded. In these patients a type III antiarrhythmic drug, such as amiodarone, may have a place, and in fact, the Basel Antiarrhythmic Study of Infarct Survival, a prospective, controlled, randomized trial using low-dose amiodarone as an antiarrhythmic agent, could demonstrate a 60% reduction in sudden death rate and a 74% reduction in arrhythmic events incidence during the first year after myocardial infarction. Therefore, in patients with repetitive ventricular ectopic activity after myocardial infarction and adequate left ventricular function, a therapeutic attempt with beta-blockers without intrinsic sympathomimetic activity seems advisable. Beside beta-adrenergic blockade, low-dose amiodarone is an alternative, especially in patients with impaired left ventricular function or other contraindications for beta-blockers.