Introduction: The evolution of defibrillation waveforms has dramatically progressed over time. Monophasic waveform became the standard waveform used in most defibrillators until the 1980s, and were progressively replaced after year 2000 by newer biphasic waveforms with different patterns: initially the biphasic rectilinear waveform, then biphasic truncated exponential (BTE) waveform with High Energy (HE) or Low Energy (LE) or Pulsed Energy (PE).
Aim: Our aim was to collect data regarding the efficacy of low, high and pulsed energy of biphasic truncated exponential waveforms, in cardioversion of atrial fibrillation through a systematic research on the literature.
Methods: A systematic research on PubMed and Science Direct, with key words (cardioversion atrial fibrillation biphasic waveform) and filters (title/abstract, clinical trial, English) provided 38 articles. A further selection was made by their title and abstract leading to a final selection of 6 articles. Efficacy was defined as return to sinus rhythm.
Results: The graphic provides cumulative shock success versus cumulative energy for different BTE waveforms: 4 High Energy (HE), 3 Low Energy (LE) and 3 Pulsed Energy (PE). Legend of the graphic indicates for each study the year of publication, the recruitment period, the sample size, the delay between cardioversion and observed rhythm, and the percentage of patients in atrial flutter when appropriate. Although the studies present major disparities, the efficacy concentrates within 85% and 95%.
Conclusion: During cardioversion of atrial fibrillation, cumulative shock success of high, low or pulsed energy biphasic truncated exponential waveforms are rather similar, with efficacy at last shock ranging between 85% and 95%.