Monophasic and biphasic shock for transthoracic conversion of atrial fibrillation: Systematic review and network meta-analysis.

Objectives: Conduct a systematic review of the literature to compare the efficacy of different biphasic and monophasic shock waveforms technologies for transthoracic cardioversion of Atrial Fibrillation (AF).

Methods: We searched PubMed, EMBASE, The Cochrane Library, LILACS and ClinicalTrials.gov databases for randomized clinical trials comparing two or more defibrillation waveforms when performing elective transthoracic cardioversion of AF. The outcomes assessed were 1st shock success, overall success, cumulative energy and number of shocks to restore Normal Sinus Rhythm.

Results: Were included 23 trials involving 3046 patients, 5 biphasic and the monophasic waveform. Direct meta-analysis revealed that Biphasic waveforms have higher chance to achieve cardioversion in the 1st shock (OR: 3.2; 95% CI 2.2-4.7) and after a sequence of attempts (OR:2.4; 95% CI 1.5-3.9), requiring 296 less Joules (95% CI 356-237) and 0.74 less shocks (95%CI 1.03-0.44) when compared to Monophasic. Network meta-analysis showed no significant differences between the Biphasic technologies of PhysioControl ADAPTIV, Philips SMART and ZOLL Rectilinear, in any of the four outcomes.

Conclusion: The evidences points to a Biphasic waveform superiority over Monophasic to perform AF cardioversion, supporting current guidelines to use less energy when using a Biphasic defibrillator. It is suggested that the Biphasic defibrillators from PhysioControl ADAPTIV, Philips SMART and ZOLL Rectilinear have similar efficacy and the use of any of them may result in similar chances, energy and number of shocks to achieve successful AF cardioversion.