Time-dependent Amiodarone Treatment in Atrial Fibrillation

An open randomized clinical trial was conducted that included 60 emergency adult patients who were candidates for drug cardioversion after first symptomatic episodes of AF.

The patients were randomized in equal proportions and sequentially placed in one of two treatment groups; no patient knew to which group he or she belonged. The first group received intravenous amiodarone infusions at doses of 5 mg/Kg for over 30 min, followed by 20 mg/Kg until 24 hours was reached. The second group received intravenous amiodarone infusions at doses of 5 mg/Kg for over 30 min, followed by 20 mg/Kg every 24 hours for up to 72 hours.

All patients were continuously monitored using electrocardiograms, and echocardiograms were performed within 24 hours after the randomized trial began. The exact time of each patient's cardioversion was documented. In addition, general laboratory tests, lipid profiles, thyroid profiles and chest X-rays were obtained for all patients.

A sample size of 30 subjects in each group was calculated. A conversion rate of 60% was assumed, according to literature, and an estimated increase to 90% was assumed for the experimental group to find differences with a power of 0.8 and an alpha error of 0.05.

The primary goal was to obtain was a sinus rhythm conversion rate. The secondary goal was to obtain a combined complication rate by noting various complications in the patients, such as phlebitis, symptomatic hypotension that required vasopressors, bradycardia, nausea, vomiting and any organ embolism.

Inclusion criteria

• ≥18 years old
• Emergency patients
• First symptomatic episodes of Atrial Fibrillation

Exclusion criteria

• Hemodynamic instability,
• Previous use of antiarrhythmic drugs
• Use of digoxin seven or fewer days prior to the study
• Active thyroid disease
• Known adverse reactions to amiodarone
• Other ventricular arrhythmias
• Contraindications for anticoagulation
• Acute renal failure
• Chronic liver disease
• Transaminase levels that were twice the normal levels
• Acute pulmonary edema
• Uncontrolled hypertension (> 180/110 mmHg)
• Unstable angina
• Patients who were pregnant and/or breast feeding