Basel Antiarrhythmic Study of Infarct Survival - BASIS

Description:

Amiodarone for persistent asymptomatic arrhythmias after myocardial infarction.

Hypothesis:

An individualized approach to optimized therapy for patients with persisting asymptomatic complex arrhythmias after MI could improve survival in comparison to a standardized treatment using low-dose amiodarone.

Study Design

Study Design:

Patients Screened: 1,220
Patients Enrolled: 312
Mean Follow Up: 1 year
Mean Patient Age: 61±7 years
Female: 14
Mean Ejection Fraction: 43±16%

Patient Populations:

< 71 years of age
Admitted to coronary care unit with acute MI
Asymptomatic complex ventricular ectopic activity on a 24-h electrocardiograph (ECG) recording before hospital discharge

Exclusions:

Death in the hospital
Symptomatic arrhythmias or cardiovascular surgery during hospitalization
Life-threatening co-morbidity
Unavailability for follow-up evaluation

Primary Endpoints:

Total mortality

Secondary Endpoints:

Sudden death
Sustained ventricular tachycardia (> 10 consecutive beats)
Ventricular fibrillation with successful resuscitation

Drug/Procedures Used:

Amiodarone group
Amiodarone 1,000 mg qd orally for 5 days
Followed by 200 mg qd; increased in 4 patients, reduced in 5 patients to 100 mg qd
Individual treatment group
Initial: quinidine (n=70) or mexiletine (n=79), dosed for efficacy and side effects
Alternatives: propafenone (n=17), flecainide (n=14), sotalol (n=5), disopyramide (n=4), prajmaline (n=4), disopyramide n=4), or combinations
Amiodarone (n=9) after an average of 3.3 drug trials

Concomitant Medications:

Propranolol

Principal Findings:

At 1 year, 30 patients died; 10 in individualized treatment group, 5 in amiodarone group, 15 in control group.

Amiodarone reduced the total mortality rate by 61% from that in the control group (p <0.05).

Amiodarone reduced the total number of arrhythmic events by 66% compared to controls (p <0.01).

Survival curves did not differ between groups after the first year. The probability of death after 84 months was 30% in the amiodarone group, and 45% in the untreated group, and was significantly lower in the amiodarone group with respect to all deaths (p = 0.024) and cardiac deaths (p=0.027).

Interpretation:

Low-dose amiodarone decreases mortality the first year after MI in patients at high risk of sudden death. Survival curves appear to remain parallel thereafter.

References:

1. J Am Coll Cardiol 1990; 16: 1711-1718. Final results
2. Am J Cardiol 1992; 69:1399-402 Amiodarone effect
3. Schweiz Med Wochenschr 1993;123:533-6 Long-term benefit
4. Circulation 1993; 87:309-11 Long-term benefit

Clinical Topics: Arrhythmias and Clinical EP, SCD/Ventricular Arrhythmias, Novel Agents, Statins

Keywords: Myocardial Infarction, Quinidine, Coronary Care Units, Ventricular Fibrillation, Prajmaline, Death, Sudden, Electrocardiography, Tachycardia, Ventricular, Disopyramide, Propafenone, Probability, Sotalol, Flecainide, Mexiletine


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