[Efficacy and secondary effects of chronic treatment with amiodarone]

Long-term therapy with amiodarone has been associated with a high incidence of adverse side effects, that precludes its indication for common cardiac arrhythmias. We have prospectively studied 218 patients (pts), aged 32-87 years, under chronic amiodarone therapy that were followed for 2 years and evaluated for efficacy and adverse side effects. Previous amiodarone treatment ranged from 1 to 135 months. Cardiac arrhythmias were paroxysmal AF (PAF) in 120 pts, sustained VT (SVT) in 36 pts, paroxysmal supraventricular tachycardia (PSVT) in 21 pts, unsustained VT (UVT) in 18 pts and miscellaneous in 23 pts. Amiodarone doses ranged from 500 to 4200 mg per week. Amiodarone was effective in 65% of all patients. No difference was observed between efficacy and type of arrhythmia. Dermatologic toxicity was found in 36%, neurologic toxicity in 23%, thyroid toxicity in 13.4% and pulmonary fibrosis en 2.5% of pts. Amiodarone was discontinued routinely when pulmonary toxicity was present. We conclude that amiodarone therapy is effective in a wide spectrum of arrhythmias. Although drug therapy was associated with a high incidence of adverse side effects, these did not preclude continuation of treatment.