[Effects of pretreatment with amiodarone infusion in patients with persistent atrial fibrillation submitted to external electrical cardioversion: a single center experience].

Background: Several studies demonstrated the efficacy of amiodarone pretreatment in achieving bet-ter outcomes after electrical cardioversion of atrial fibrillation. In the majority of cases, oral amiodarone for at least 1 month was administered, with the result of lengthening of pre-cardioversion time. Only one study in the literature reported high-dose amiodarone infusion, showing an increase in the incidence of slow arrhythmias. The aim of this study was to test the efficacy of pretreatment infusion of a single dose of amiodarone few hours before electrical cardioversion in restoring sinus rhythm and reducing the incidence of early arrhythmic recurrences.

Methods: The study was retrospective. We analyzed a population of 155 patients with persistent atrial fibrillation, from May 2003 to November 2005. The first group of 86 patients was treated with amiodarone at the dose of 4 mg/kg in 30 min, few hours before electrical cardioversion; the second group of 69 patients was treated with electrical cardioversion without pharmacological pretreatment. The two groups were homogeneous for age, sex, coronary artery disease, duration of arrhythmia, atrial dimensions, left ventricular ejection fraction, and paddle position for electrical cardioversion.

Results: There were no significant differences between the two groups in terms of efficacy of cardioversion (95.3 vs 91.3%, p = NS). Pretreatment with bolus of amiodarone significantly reduced the incidence of immediate recurrence (3.5 vs 17.4%, p < 0.05) and the mix of immediate and early recurrence (19.7 vs 33.3%, p < 0.05). There were no significant differences in the incidence of late recurrences (17.4 vs 13%, p = NS). There were no significant bradyarrhythmias in the two groups. Amiodarone pretreatment did not reduce energy delivery to obtain cardioversion.

Conclusions: Amiodarone pretreatment with intravenous bolus few hours before electrical cardioversion reduces short-term recurrences of atrial fibrillation. It does not reduce energy delivery of electrical cardioversion and does not increase the incidence of slow arrhythmias. Randomized prospective studies are warranted to confirm these findings.