Ventricular pacing threshold after transthoracic external defibrillation with two different waveforms: an experimental study.

Aims: Although an increase in the ventricular pacing threshold (VPT) has been observed after administration of transthoracic shock for ventricular defibrillation, few studies have evaluated the phenomenon with respect to the defibrillation waveform energy. Therefore, this study examined the VPT behaviour after transthoracic shock with a monophasic or biphasic energy waveform.

Method And Results: Domestic Landrace male piglets implanted with a permanent pacemaker stimulation system were divided into three groups: no ventricular fibrillation (VF) induction and transthoracic shock with monophasic or biphasic energy (group I); VF induction, 1 min of observation without intervention, 2 min of external cardiac massage, and transthoracic shock with monophasic or biphasic energy (group II); and VF induction, 2 min of observation without intervention, 4 min of external cardiac massage, and transthoracic shock with monophasic or biphasic energy (group III).