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Long-term benefit of 1-year amiodarone treatment for persistent complex ventricular arrhythmias after myocardial
M E Pfisterer1, W Kiowski, H Brunner
1Department of Internal Medicine, University Hospital Clinics, Basel, Switzerland.
Insights
Low-dose amiodarone improved survival in post-myocardial infarction patients. This survival benefit persisted for years, even after amiodarone discontinuation, highlighting early treatment importance.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Basel Antiarrhythmic Study of Infarct Survival trial identified 1-year survival improvement with low-dose amiodarone in post-myocardial infarction patients with complex ventricular arrhythmias.
- Study assessed long-term outcomes after 1-year amiodarone discontinuation.
Purpose of the Study:
- To evaluate if the survival benefit of amiodarone persists long-term after treatment cessation.
- To assess long-term mortality in patients treated with amiodarone versus a control group post-myocardial infarction.
Main Methods:
- Long-term follow-up of patients from the amiodarone-treated (n=98) and control (n=114) groups.
- Actuarial life-table analysis (Kaplan-Meier) to determine survival probabilities and mortality rates.
- Data collected on survival and cause of death for 96% of patients over a mean follow-up of 72 months.
Main Results:
- After 84 months, 84-month survival was 70% for amiodarone patients vs. 55% for controls.
- Overall mortality was significantly lower in the amiodarone group (p=0.03), including cardiac death (p=0.047).
- Mortality difference was attributed to the first year of amiodarone treatment; no significant difference after discontinuation.
Conclusions:
- The survival benefit of amiodarone in high-risk post-myocardial infarction patients persists for years.
- Early amiodarone treatment is crucial, as late-stage mortality rates (sudden and cardiac death) are low and may not require continued therapy.
Background:
In the Basel Antiarrhythmic Study of Infarct Survival trial, low-dose amiodarone improved 1-year survival in patients with asymptomatic complex ventricular arrhythmias persisting 2 weeks after myocardial infarction. To assess whether this beneficial effect persisted despite discontinuation of amiodarone after 1 year, the long-term outcomes of all patients of the amiodarone-treated group (initially n = 98) and those of the control group (n = 114) were assessed.
Methods And Results:
After a mean follow-up of 72 (55-125) months, information on 96% of patients (203 of 212) was obtained regarding survival or cause of death. The probability of death after 84 months according to actuarial life-table analysis (Kaplan-Meier) was 30% for the amiodarone-treated patients and 45% for control patients. For the total follow-up, mortality remained significantly lower in the amiodarone group versus the control group regarding all deaths (p = 0.03) as well as cardiac death (p = 0.047). This mortality reduction was entirely due to the first-year amiodarone effect, since there was no significant mortality difference between groups when considering survival after discontinuation of amiodarone only.
Conclusions:
These data suggest that the beneficial effect of amiodarone on survival in this high-risk group of patients persists for several years. In addition, the results stress the importance of early treatment after myocardial infarction, whereas the rate of sudden death and all cardiac death is low (1.6% and 4.1% per year, respectively) during late follow-up and therefore may not warrant further therapy.