Transthoracic cardioversion with damped biphasic waveform shocks

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Introduction

The biphasic waveform has been shown to have high efficacy for transthoracic ventricular defibrillation [1,2]. The objective of this prospective study was to evaluate the clinical efficacy of biphasic waveforms for cardioversion of atrial fibrillation.

Methods

The pulse is an asymmetric quasi-sinusoidal biphasic waveform. The peak current of the second phase was approximately half that of the first phase. Transthoracic cardioversion (29 emergent, 71 urgent and 41 elective) were performed in 141 patients who were receiving antiarrhythmic drugs (e.g., amiodarone). Ischemic heart disease was the most common (about 90%) etiology. Shocks were delivered through 11.5 cm paddles in the antero-apical position. The maximum delivered energy was 195 J.

Results

See Table.

Conclusions

Our clinical results demonstrate that the biphasic waveform with a delivered energy of ≤ 195 J was highly effective in cardioverting atrial fibrillation.

Table