A comparison between monophasic and biphasic defibrillation for the cardioversion of persistent atrial fibrillation in patients with and without heart failure.

AIMS: Atrial fibrillation (AF) and heart failure commonly coexist. Restoring sinus rhythm using external direct current cardioversion (DCCV) may improve left ventricular function, exercise capacity and quality of life (QoL). However, DCCV may be less successful at restoring sinus rhythm in patients with heart failure. We aimed to determine whether biphasic DCCV was superior to monophasic DCCV for the restoration of sinus rhythm in patients with heart failure. METHODS: 592 consecutive cardioversion procedures were performed on 503 patients for persistent AF, 261 (44%) procedures using monophasic defibrillation and 331 (56%) using biphasic. Patients with symptomatic heart failure were identified for further analysis. RESULTS: 173 cardioversions were performed on 149 patients with heart failure. The overall success rate of cardioversion in this group was 82.7% (83.3% and 82.2% for monophasic and biphasic respectively). There was no difference in the success rate of cardioversion for those with heart failure compared to those without heart failure (p = 0.141). Furthermore, there was no substantial difference in success rates according to defibrillation type (83.3% v. 84.2% for monophasic and 82.2% v. 88.5% for biphasic, p = 0.502 and 0.085 respectively). CONCLUSION: External defibrillation is similarly effective at restoring SR in patients with and without HF and both mono- and biphasic shocks have a high rate of success. However, significantly less energy (maximal and cumulative) is required to restore SR using biphasic defibrillation.