Effect of shock polarity on the efficacy of transthoracic atrial defibrillation

DC cardioversion of persistent atrial fibrillation: A comparison of two protocols

“…A randomised study of 110 patients found no effect on efficacy of transthoracic cardioversion using a step up protocol starting with 50 J with the atrial defibrillation threshold similar for both polarities (198 T 103 anteroposterior, 212 T 107 posteroanterior) [6]. This is supported by the findings of the present study where reversal of shock polarity in the third sequence resulted in comparable shock success.…”

“…The delivered energy, paddle position and paddle pressure may influence the cardioversion success rate [2][3][4][5]. Reversed shock polarity has been used when previous attempts to cardiovert have failed but this approach has not been supported by the literature [6]. Cardioversion has been traditionally performed under general anaesthesia but there is a gradual shift to using intravenous benzodiazepines for sedation during elective DC cardioversion of atrial arrhythmias.…”

Electrical Cardioversion for AF—The State of the Art

“…However, both polarities achieved ∼95% success at 360 J and there was limited success after crossover. Rashba et al 38 investigated shock polarity in the AP electrode configuration (here an anterior cathode is the norm) in a group of 110 AF patients with escalating energies. No difference was found in either cardioversion success or DFT.…”

Present Understanding of Shock Polarity for Internal Defibrillation: The Obvious and Non‐Obvious Clinical Implications

“…This will not interfere with successful defibrillation. (This model also helps explain why polarity is irrelevant with external shocks 22 . Since no electrode is close to the heart, there is no asymmetry in the launching of new wavefronts with the external shock.…”