Biphasic versus monophasic shock waveform for conversion of atrial fibrillation

Objectives This study compared a biphasic waveform with a conventional monophasic waveform for cardioversion of atrial fibrillation (AF). Background Biphasic shock waveforms have been demonstrated to be superior to monophasic shocks for termination of ventricular fibrillation, but data regarding biphasic shocks for conversion of AF are still emerging. Methods In an international, multicenter, randomized, double-blind clinical trial, we compared the effectiveness of damped sine wave monophasic versus impedance-compensated truncated exponential biphasic shocks for the cardioversion of AF. Patients received up to five shocks, as necessary for conversion: 100 J, 150 J, 200 J, a fourth shock at maximum output for the initial waveform (200 J biphasic, 360 J monophasic) and a final cross-over shock at maximum output of the alternate waveform. Results Analysis included 107 monophasic and 96 biphasic patients. The success rate was higher for biphasic than for monophasic shocks at each of the three shared energy levels (100 J: 60% vs. 22%, p Conclusions For the cardioversion of AF, a biphasic shock waveform has greater efficacy, requires fewer shocks and lower delivered energy, and results in less dermal injury than a monophasic shock waveform.