The effect of oral magnesium, alone or as an adjuvant to sotalol, after cardioversion in patients with persistent atrial fibrillation

Aims To determine whether magnesium given orally decreases the recurrence r ate of atrial fibrillation after elective direct current cardioversion of p ersistent atrial fibrillation. Methods and Results Consecutive outpatients were randomized to treatment wi th oral magnesium (10.3 mmol) or placebo twice daily in a double-blind fash ion. Two groups were studied; magnesium study: 170 patients with atrial fib rillation persistent for >1 month, scheduled for their first direct current cardioversion. No concomitant antiarrhythmic drugs of class I or III were allowed. Sotalol and magnesium study: 131 patients with recurrence of persi stent atrial fibrillation after previous direct current cardioversion, or a history of paroxysmal atrial fibrillation, treated with sotalol. Patients were followed until recurrence of atrial fibrillation or for at least 6 mon ths. Magnesium study: at cardioversion 67 of 85 (79%) in the placebo group and 64 of 85 (75%) in the magnesium group had converted to sinus rhythm. At the end of the study, with a follow-up of 6 to 42 months, 15% of patients in the placebo group and 19% of patients in the magnesium group remained in sinus rhythm (Log rank test: P=0.37). Sotalol and magnesium study: pharmac ological conversion to sinus rhythm, after oral treatment, was achieved in 34 of 131 (26%) patients. Sinus rhythm. with or without cardioversion, was restored in 89% and 85% of the patients in the placebo and magnesium groups , respectively. At the end of the study, with a follow-up of 6 to 42 months , 37% of patients in the placebo group and 30% of patients in the magnesium group remained in sinus rhythm (Log rank test: P=0.64). Conclusion In patients with persistent atrial fibrillation, oral treatment with magnesium alone or as an adjuvant to sotalol, does not influence the r ecurrence rate of atrial fibrillation after elective cardioversion. (Eu Hea rt J 2000; 21: 1177-1185) (C) 2000 The European Society of Cardiology.