Acute beta-adrenoceptor blockade improves efficacy of ibutilide in conversion of atrial fibrillation with a rapid ventricular rate.

Abstract

AIMS:

Activation of beta-adrenoceptors attenuates prolongation of action potential duration induced by blockade of the delayed rectifier potassium current. We examined whether acute administration of beta-blocker could enhance ibutilide (IB) efficacy in conversion of atrial fibrillation (AF) with a rapid ventricular rate.

METHODS AND RESULTS:

Ninety patients (aged 63 +/- 13.5 years) with rapidly conducting AF were randomized in to two groups. Group A (n = 44) received esmolol titrated to achieve a heart rate of <100 bpm followed by IB co-administration, while Group B (n = 46) were treated with IB as monotherapy. In Group A, 29 patients (67%) converted to sinus rhythm (SR) compared with 21 (46%) in Group B (P = 0.04). The use of esmolol was the most important predictor for cardioversion (P = 0.009). The slower the heart rate at the time of IB initiation, the higher the likelihood for cardioversion (P = 0.015). Patients in Group A had significantly shorter corrected QT interval (QTc) at the time of conversion than those in Group B (433 vs. 501 ms, P = 0.003). Two patients in Group A developed severe bradycardia, whereas three patients in Group B developed severe ventricular tachycardia (VT).

CONCLUSION:

Compared with IB monotherapy, the combination therapy of esmolol and IB appears to be more effective in conversion of rapidly conducting AF back to SR. The addition of beta-blocker reduces QTc prolongation and diminishes the risk of VT at the expense, however, of increased bradycardic events.

• Authors: Nikolaos Fragakis, Athanasios Bikias, Ioannis Delithanasis, Melania Konstantinidou, Nikolaos Liakopoulos, Miltiadis Kozirakis, George Katsaris
• Journal: Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology (Europace) Vol. 11 Issue 1 Pg. 70-4 (Jan 2009) ISSN: 1532-2092 [Electronic] England
• PMID: 18987127 (Publication Type: Journal Article, Randomized Controlled Trial)

Chemical References

• Adrenergic beta-Antagonists
• Anti-Arrhythmia Agents
• Propanolamines
• Sulfonamides
• ibutilide
• esmolol

Topics

• Adrenergic beta-Antagonists (administration & dosage)
• Anti-Arrhythmia Agents (administration & dosage, adverse effects)
• Atrial Fibrillation (complications, prevention & control)
• Drug Synergism
• Female
• Humans
• Male
• Middle Aged
• Propanolamines (administration & dosage)
• Sulfonamides (administration & dosage, adverse effects)
• Treatment Outcome
• Ventricular Fibrillation (chemically induced, prevention & control)