Ibutilide in persistent atrial fibrillation refractory to conventional cardioversion methods

Vernakalant-facilitated electrical cardioversion: comparison of intravenous vernakalant and amiodarone for drug-enhanced electrical cardioversion of atrial fibrillation after failed electrical cardioversion

AIMS

Electrical cardioversion is one cornerstone for the rhythm control strategy of atrial fibrillation (AF), which is, however, hampered by immediate AF recurrence (IRAF) or failed electrical cardioversion (FECV). We aimed to investigate the potential role of vernakalant for facilitated electrical cardioversion in cardioversion-resistant AF.

METHODS AND RESULTS

The subjects of this study were 63 patients referred to the Heart Centre Leipzig between November 2011 and May 2014 for transthoracic electrical cardioversion of AF. All patients experienced after antiarrhythmic-naïve electrical cardioversion either IRAF (n = 44; 70%) or FECV (n = 19; 30%). After drug infusion, electrical cardioversion was successful in 66.7% of vernakalant-treated as opposed to 46.7% of amiodarone-treated patients (P = 0.109). Multivariate analysis revealed treatment with vernakalant (OR 0.057, 95% CI 0.006-0.540, P = 0.013), treatment with ACEI or ARB (OR 0.101, 95% CI 0.015-0.691 P = 0.019), and IRAF after initial CV (OR 0.047, 95% CI 0.004-0.498, P = 0.011) as predictors for successful, drug-facilitated electrical cardioversion. Subgroup analysis of 18 patients with previous AF ablation revealed a significantly higher success rate of electrical cardioversion after infusion of vernakalant than after infusion of amiodarone (66.7 vs. 11.1%, P = 0.016).

CONCLUSION

Vernakalant may therefore be considered as a useful agent for facilitated electrical cardioversion in cardioversion-resistant AF.

Ibutilide therapy for atrial fibrillation: 5-year experience in a community hospital

Many institutions restrict the use of ibutilide because of the potential risk of polymorphic ventricular tachycardia (PMVT). Over a 5-year period from June 2000 to May 2005, 238 patients, 151 men and 87 women, with a mean age of 67.1 years (range, 22-94 years), received intravenous ibutilide at our institution. Ibutilide was administered by nurses or physicians in 4 clinical settings: emergency department (n = 80), intensive care unit (n = 11), patient room on telemetry (n = 107), and in the cardiac catheterization/electrophysiology laboratory (n = 40). Conversion to sinus rhythm occurred in 59% of patients outside the catheterization/electrophysiology laboratory. The incidence of PMVT was 1.7%. Three patients had brief nonsustained PMVT and 1 patient had a sustained PMVT. There was no difference in outcome whether a physician was present at the time of ibutilide administration. Our data suggest that ibutilide is a safe and efficacious drug when ordered by experienced physicians in properly selected patients in a variety of monitored settings.

Monotherapy versus Combination Therapy with Class III Antiarrhythmic Agents to Attenuate Transmural Dispersion of Repolarization: A Potential Risk Factor for Torsade de Pointes

Class III antiarrhythmic agents are used for conversion to and maintenance of sinus rhythm from arrhythmias of atrial or ventricular origin. Monotherapy can be limited by adverse events or recurrent arrhythmias. Sotalol, dofetilide, and ibutilide may induce torsade de pointes in 2-8% of patients, whereas amiodarone induces torsade de pointes in less than 1%. We reviewed the literature regarding the possible combination of class III antiarrhythmics and risk for inducing torsade de pointes. Animal studies using amiodarone plus sotalol or d-sotalol suggest that these drug combinations prolong the QTc interval but do not induce torsade de pointes. Similar data extracted from human studies of ibutilide in patients also receiving amiodarone or sotalol showed greater efficacy with combination therapy than with monotherapy, without increased torsade de pointes induction. Reduced transmural dispersion of repolarization with amiodarone and sotalol combination therapy may serve as a mechanism for reducing the risk of torsade de pointes compared with sotalol monotherapy.