Synchronized defibrillation for ventricular fibrillation.

Abstract

OBJECTIVE:

Optimization of defibrillation success is important to improve efficacy and minimize post-shock sequelae. Previous work has suggested an improvement in shock success when an intracardiac shock is delivered synchronized to the upslope of a VF wave. We investigated the efficacy of transthoracic defibrillation success using a novel external biphasic defibrillator which delivers shocks synchronized to the upslope of the surface ECG.

METHODS:

A prospective, controlled, randomized study in a research institute laboratory of male and female pigs (54.2±1.8 kg). Ventricular fibrillation (VF) was induced in 10 anaesthetized and ventilated pigs. Shocks were delivered randomly from a biphasic defibrillator in synchronized or non-synchronized mode via self-adhesive electrode pads following 30 s of VF. Energy settings at 50, 70, 80, and 100J were randomly tested. VF amplitude, impedance, and shock outcome were recorded and analysed digitally.

RESULTS:

A total of 300 shocks were delivered. Synchronized shocks were delivered on the upslope of the VF wave in 99% of cases. There was no significant difference in shock success between shocks delivered in synchronized or non-synchronized modes (p=0.695). There was no significant difference in the amplitude of VF between successful and unsuccessful shocks (p=0.163). Furthermore, there was no association between shock success and transthoracic impedance.

CONCLUSION:

The novel defibrillator used in this study was able to consistently deliver shocks on the upslope portion of the VF wave but did not show an improvement in shock success.

• Authors: Karen M Darragh, Ganesh Manoharan, Cesar Navarro, Simon J Walsh, John D Allen, John McC Anderson, Aa Jennifer Adgey
• Journal: European heart journal. Acute cardiovascular care (Eur Heart J Acute Cardiovasc Care) Vol. 1 Issue 4 Pg. 285-90 (Dec 2012) ISSN: 2048-8726 [Print] England
• PMID: 24062919 (Publication Type: Journal Article)