OBJECTIVE: To compare the efficacy of cardioversion in patients with atrial fibrillation between monophasic damped sine waveform and rectilinear biphasic waveform shocks at a high initial energy level and with a conventional paddle position. DESIGN: Prospective randomised study. PATIENTS AND SETTING: 227 patients admitted for cardioversion of atrial fibrillation to a tertiary referral centre. RESULTS: 70% of 109 patients treated with an initial 200 J monophasic shock were cardioverted to sinus rhythm, compared with 80% of 118 patients treated with an initial 120 J biphasic shock (NS). After the second shock (360 J monophasic or 200 J biphasic), 90% of the patients were in sinus rhythm in both groups. The mean cumulative energy used for successful cardioversion was 306 J for monophasic shocks and 159 J for biphasic shocks (p < 0.001). CONCLUSIONS: A protocol using monophasic waveform shocks in a 200-360 J sequence has the same efficacy (90%) as a protocol using rectilinear biphasic waveform shocks in a 120-200 J sequence. This equal efficacy is achieved with a significantly lower mean delivered energy level using the rectilinear biphasic shock waveform. The potential advantage of lower energy delivery for cardioversion of atrial fibrillation needs further study.

Atrial Fibrillation/*therapy, Comparative Study, Electric Countershock/*methods, Female, Humans, Male, Middle aged, Prospective Studies, Recurrence
Erasmus MC: University Medical Center Rotterdam

Scholten, M.F, Szili-Török, T, Jordaens, L.J.L.M, & Klootwijk, A.P.J. (2003). Comparison of monophasic and biphasic shocks for transthoracic cardioversion of atrial fibrillation. Heart, 89(9), 1032–1034. Retrieved from http://hdl.handle.net/1765/8351