Heart 89:1032-1034 doi:10.1136/heart.89.9.1032
  • Cardiovascular medicine

Comparison of monophasic and biphasic shocks for transthoracic cardioversion of atrial fibrillation

  1. M Scholten,
  2. T Szili-Torok,
  3. P Klootwijk,
  4. L Jordaens
  1. Erasmus University Medical Centre, Thoraxcentre, Department of Clinical Electrophysiology, Rotterdam, Netherlands
  1. Correspondence to:
    Dr Marcoen Scholten, Department of Clinical Electrophysiology, Thoraxcentre, Erasmus University Medical Centre, Dr Molewaterplein 40, 3015 GM, Rotterdam, Netherlands;
  • Accepted 25 March 2002


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.