Intravenous amiodarone is a recognised treatment alternative for the conversion of atrial fibrillation to sinus rhythm.^1–3 Consensus regarding dosage and duration of treatment has not been reached.^4,5 Our coronary care unit routinely uses intravenous amiodarone for conversion of supraventricular arrhythmia in various clinical settings. Following a loading dose of 300 mg/30 mins, two alternative dosages of intravenous maintenance treatment—50 mg/hour and 100 mg/hour—employed. We compared the efficacy and safety of these two regimens in an open randomised study.

METHOD

Patients with atrial fibrillation or flutter with duration of less than 48 hours were included. Patients with ECG evidence of transmural ischaemia, class III antiarrhythmic treatment within 14 days, cardiogenic shock, uncontrolled thyroid disease, previous symptomatic bradycardia without pacemaker, and tachycardia based on atrioventricular (AV) re-entrant mechanisms were not included. Patients developing signs of haemodynamic decompensation were cardioverted.

The primary parameter was conversion to sinus rhythm. Secondary parameters were time to sinus rhythm and time to rate control. Heart rate, QT time, and PR interval at the time of conversion, were recorded continuously. Electrocardioversion before completion of the 24 hour period and interruption of study medication because of adverse experience were separate end points. Conduction abnormalities …