Effect of high doses of magnesium on converting ibutilide to a safe and more effective agent.
Ibutilide is a class III antiarrhythmic agent indicated for cardioversion of atrial fibrillation and atrial flutter to sinus rhythm (SR). The most serious complication of ibutilide is torsades de pointes (TdP). Magnesium has been successfully used for the treatment of TdP, but its use as a prophylactic agent for this arrhythmia has not yet been established. The present study investigated whether high dose of magnesium would increase the safety and efficacy of ibutilide administration. A total of 476 patients with atrial fibrillation or atrial flutter who were candidates for conversion to SR were divided into 2 groups. Group A consisted of 229 patients who received ibutilide to convert atrial fibrillation or atrial flutter to SR. Group B consisted of 247 patients who received an intravenous infusion of 5 g of magnesium sulfate for 1 hour followed by the administration of ibutilide. Then, another 5 g of magnesium were infused for 2 additional hours. Of the patients in groups A and B, 154 (67.3%) and 189 (76.5%), respectively, were converted to SR (p = 0.033). Ventricular arrhythmias (sustained, nonsustained ventricular tachycardia, and TdP) occurred significantly more often in group A than in group B (7.4% vs 1.2%, respectively, p = 0.002). TdP developed in 8 patients (3.5%) in group A and in none (0%) in group B (p = 0.009). The administration of magnesium (despite the high doses used) was well tolerated. In conclusion, the administration of high doses of magnesium probably makes ibutilide a much safer agent, and magnesium increased the conversion efficacy of ibutilide.
Patsilinakos
Sotirios
S
Department of Cardiology, Konstantopoulio General Hospital, Athens, Greece.
Christou
Apostolos
A
Kafkas
Nikolaos
N
Nikolaou
Nikolaos
N
Antonatos
Dionysios
D
Katsanos
Spyridon
S
Spanodimos
Stavros
S
Babalis
Dimitrios
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage*; D001281:Atrial Fibrillation / Q000188:drug therapy*; D001282:Atrial Flutter / Q000188:drug therapy*; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008278:Magnesium Sulfate / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D013449:Sulfonamides / Q000009:adverse effects / Q000627:therapeutic use*; D016171:Torsades de Pointes / Q000139:chemically induced / Q000175:diagnosis / Q000517:prevention & control*; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents; D013449:Sulfonamides; C067192:ibutilide; D008278:Magnesium Sulfate