Efficacy of amiodarone for refractory supraventricular tachyarrhythmias.

Amiodarone was administered to 121 patients (82 males, 39 females; average age 59 years) with refractory atrial tachyarrhythmias. All patients had experienced recurrent atrial fibrillation, atrial flutter, or reentrant supraventricular tachycardia previously refractory to digitalis drugs, beta-adrenergic blocking agents, and an array of membrance-active preparations. Seventy-four of 121 patients (61.2%) had no evidence of organic heart disease, whereas 17 patients experienced arrhythmia as a result of coronary heart disease, nine had preexcitation syndromes, 16 had primary valvular heart disease, and five patients, had congenital heart disease. Atrial fibrillation alone or in combination with atrial flutter was the primary dysrhythmia in 95 of 121 patients (78.5%), whereas in 26 patients (21.5%) supraventricular tachycardia was the primary refractory dysrhythmia. Fifty-one patients (42%) had experienced tachyarrhythmias for more than 10 years prior to the use of amiodarone. During an average follow-up of 27.3 months, complete suppression of atrial arrhythmias occurred in 98 of 121 patients (81%), and partial suppression occurred in seven (5.8%). In 16 patients (13.2%) the drug was deemed ineffective, and in eight patients (6.6%) amiodarone was discontinued because of intolerable side effects. The average blood serum concentration among successfully treated patients was 1.9 micrograms/ml, whereas the average concentration for those with side effects was 2.3 micrograms/ml. Thus, amiodarone is an extremely effective (greater than 85%) agent for refractory atrial tachyarrhythmias. Once daily administration, generally tolerable side effects, and excellent patient tolerance render this agent an attractive option for the management of these dysrhythmias.