IV Magnesium Enhances Ibutilide in Atrial Fibrillation/Flutter Conversion

SAN FRANCISCO, CA—Srikanth Vallurupalli, MD, and colleagues from the University of Arkansas Medical Sciences, Little Rock, AR presented results at ACC.13, the American College of Cardiology's 62nd Annual Scientific Session, in support of intravenous (IV) magnesium significantly enhancing the efficacy of ibutilide in atrial fibrillation conversion and flutter.

IV magnesium is often used concomitantly with ibutilide during the treatment of atrial fibrillation and flutter to prevent torsades de pointes. Magnesium inhibits the L-type calcium channel as well as the inward rectifying potassium channel. Its effect on the efficacy of ibutilide in this setting has not been well established.

Investigators conducted a search of PubMed, Embase, and Cochrane databases to identify studies comparing the efficacy of magnesium with ibutilide vs. ibutilide alone in the conversion of atrial fibrillation and flutter. Key words such as  “magnesium,” “ibutilide,” “atrial fibrillation,” and “atrial flutter” were utilized to compile studies. Two investigators independently reviewed 12 articles after which only four studies were included in the final meta-analysis. A total of 1,143 patients were included in the analysis.

Dr. Vallurupalli presented data demonstrating that ibutilide alone vs. concomitant IV magnesium and ibutilide significantly increases the efficacy of conversion to sinus rhythm (OR 1.66, 95% CI 1.29–2.15, P<0.0001) with no significant heterogeneity among the studies included (I2=0%).  In addition, the incidence of ventricular arrhythmias was significantly reduced with magnesium (3.25% vs. 6.27%, P=0.03).

An additional cost-effectiveness analysis, results showed that combination of these medications reduces costs by decreasing the need for DC cardioversion.

Researchers concluded that IV magnesium “significantly enhanced not only the safety but also the efficacy of ibutilide in conversion of atrial fibrillation and flutter.”