Ventricular pulsed field defibrillation: preclinical feasibility study

Ventricular fibrillation (VF) is a leading cause of sudden cardiac death worldwide. Defibrillation via direct current shocks is effective but associated with significant pain and morbidity, prompting the need for alternative approaches. Reversible electroporation of cardiac tissue with pulsed electric fields (PEF) may be an effective means of terminating VF.

To assess the feasibility of PEF delivery for terminating VF.

5 acute swine models were used. Mechanical circulatory support with peripheral veno-arterial extracorporeal membrane oxygenation +/- percutaneous left ventricular assist device (Impella 5.5 L) was implemented and titrated to a mean arterial pressure ≥65 mmHg. Decapolar catheters were introduced into the endocardial right and/or left ventricle as well as epicardium. VF was induced with R on T shocks or rapid ventricular pacing. PEF was delivered with the endocardial catheter as the cathode and epicardial catheter as the anode; monophasic pulses (5-10) at 3000V, 100µs, and 200ms inter-pulse intervals were used. If VF persisted post-PEF, catheters were repositioned into regions of intact voltages for repeat delivery.

10 VF episodes were induced, 7 of which were successfully terminated with PEF delivery (70.0%). The median number of attempts to achieve VF termination was 2 (range 1-5). The post-VF rhythm was complete heart block with ventricular asystole in all successful defibrillation attempts, with no recovery after 30 minutes of observation. Significant muscle stimulation was seen with the utilized PEF parameters and catheter configurations.

Termination of VF using PEF – pulsed field defibrillation – is possible. However, further study is required to optimize delivery parameters/configurations to improve effectiveness and avoid muscle stimulation as well as conduction abnormalities.