The effect of low-dose amiodarone in prevention of paroxysmal atrial fibrillation.
The efficacy of amiodarone for atrial fibrillation (AF) prophylaxis is well established, but the large doses used until recently may be harmful during long-term therapy, especially because of the pulmonary fibrosis it generates. Recently, similar good results have been reported in using low-dose amiodarone. We studied the prophylactic effect of long-term therapy of low-dose amiodarone (200 mg/day) in 26 patients with AF of various etiologies. During a period of six months to four years, 46% of patients were free of any arrhythmic attack. The paroxysmal attacks of AF continued in 35% of patients, but with a lower frequency. In 19% of patients AF became chronic during amiodarone therapy. The best results were registered in patients over sixty, with stable sinus rhythm in 75% of cases, probably in relation to the ischemic etiology of AF and the anti-ischemic associated effect of amiodarone. The stability of sinus rhythm was greater (50% vs 38%, p < 0.05) when the treatment with amiodarone was started within the first six months from the first AF attack. Our results supported the use of low-dose amiodarone as a first-line drug for the long-term prophylaxis of AF, mainly in older patients.