Chest
Volume 117, Issue 6, June 2000, Pages 1538-1545
Journal home page for Chest

Clinical Investigations
CARDIOLOGY
Amiodarone as a First-Choice Drug for Restoring Sinus Rhythm in Patients With Atrial Fibrillation

https://doi.org/10.1378/chest.117.6.1538Get rights and content

Study objectives

To investigate the efficacy and safety of amiodarone administered as the drug of first choice in the conversion of atrial fibrillation, regardless of its duration.

Design

Prospective, randomized, controlled clinical study.

Setting

Tertiary cardiac referral center.

Patients

Two-hundred eight consecutive patients (102 men; mean [± SD] age, 65 ± 10 years) with atrial fibrillation.

Interventions

One-hundred eight patients received amiodarone, and 100 patients received placebo treatment. Patients randomized to amiodarone received 300 mg IV for 1 h, and then 20 mg/kg for 24 h. They were also given 600 mg/d orally, divided into three doses, for 1 week, and thereafter 400 mg/d for 3 weeks. Patients randomized to placebo treatment received an identical amount of saline solution IV over 24 h, and oral placebo treatment for 1 month.

Measurements and results

Baseline clinical characteristics were similar in the two groups. Conversion to sinus rhythm was achieved in 87 of 108 patients (80.05%) who received amiodarone, and in 40 of 100 patients (40%) in the placebo group (p < 0.0001). Statistical analysis showed that the duration of the arrhythmia and the size of the left atrium affected both the likelihood of conversion to sinus rhythm and the time to conversion in both groups. No side effects requiring discontinuation of treatment were observed in either group.

Conclusions

Amiodarone appears to be safe and effective in the termination of atrial fibrillation. However, extreme cases with a large left atrium and long-lasting arrhythmia need long-term therapy.

Section snippets

Patients

Two-hundred eight consecutive patients (102 men and 106 women) aged 27 to 78 years (mean [± SD], 65 ± 10 years), with symptoms of atrial fibrillation, who came to the emergency department or were treated in our clinic, were included in this study. Patients with a recent myocardial infarction, heart surgery within the last 6 months, unstable angina, acute myocarditis, acute pericarditis, severe uncontrolled heart failure (ejection fraction < 30%), or cardiogenic shock were excluded, as were

Results

Of the 208 patients who were enrolled, 108 patients were randomized to amiodarone and 100 to placebo treatment. There were no significant differences between the amiodarone and placebo groups in baseline patient characteristics (Table 1). Echocardiographic studies were performed in 97 patients while they were in atrial fibrillation (37 receiving amiodarone and 60 receiving placebo treatment), and in 111 patients while they were in sinus rhythm (within 24 h after conversion). In 31 patients,

Discussion

According to our findings, a patient receiving amiodarone has six times better odds of converting to sinus rhythm than a patient receiving placebo treatment. However, factors such as the duration of the arrhythmia and the size of the left atrium appear to influence the conversion rate of amiodarone, mainly in extreme cases. The overall conversion rate of amiodarone is very high (> 90%), but in patients with a very large left atrium and chronic atrial fibrillation, the rate falls to relatively

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