Effectiveness of amiodarone in resistant arrhythmias.

Amiodarone is used in the treatment of previously drug-resistant supraventricular and ventricular arrhythmias. We report our experience with amiodarone in 8 patients. Five patients had paroxysmal atrial flutter, one had paroxysmal atrial fibrillation, one had supraventricular tachycardia, and one ventricular tachycardia. Considerable improvement, both objectively and subjectively, was observed in all patients. Side effects were as follows: all patients had corneal microdeposits, one developed left bundle branch block which resolved on stopping amiodarone, and one reported constipation and abdominal pains. Six patients have been treated for 10-28 months; 3 developed tolerance at 4-14 months after the introduction of amiodarone therapy, but symptoms improved with increased dosage. It is important to watch for the development of tolerance to this drug.