The impact of defibrillation current and pad position on return of spontaneous circulation during refractory ventricular fibrillation

Sheldon Cheskes; Ian R Drennan; Linda Turner; Sandeep V Pandit; Robert G Walker; Tyson G Taylor; Shelley L McLeod; Paul Dorian

doi:10.1016/j.resuscitation.2026.111061

The impact of defibrillation current and pad position on return of spontaneous circulation during refractory ventricular fibrillation

Resuscitation. 2026 May:222:111061. doi: 10.1016/j.resuscitation.2026.111061. Epub 2026 Mar 17.

Authors

Sheldon Cheskes¹, Ian R Drennan², Linda Turner³, Sandeep V Pandit⁴, Robert G Walker⁵, Tyson G Taylor⁵, Shelley L McLeod⁶, Paul Dorian⁷

Affiliations

¹ Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Sunnybrook Centre for Prehospital Medicine, Toronto, Ontario, Canada; Sunnybrook Research Institute and Department of Emergency Services, Sunnybrook Health Science Centre, Toronto, Ontario, Canada; Division of Emergency Medicine, Department of Family and Community Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; First60, St. Michaels Hospital, Toronto, ON, Canada. Electronic address: sheldon.cheskes@sunnybrook.ca.
² Sunnybrook Research Institute and Department of Emergency Services, Sunnybrook Health Science Centre, Toronto, Ontario, Canada; Division of Emergency Medicine, Department of Family and Community Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; First60, St. Michaels Hospital, Toronto, ON, Canada; Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.
³ Sunnybrook Centre for Prehospital Medicine, Toronto, Ontario, Canada.
⁴ Zoll Medical Inc. Chelmsford, MA, United States.
⁵ Stryker Emergency Care. Redmond, Washington, United States.
⁶ Division of Emergency Medicine, Department of Family and Community Medicine, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada; Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada; Schwartz/Reisman Emergency Medicine Institute, Sinai Health, Toronto, Ontario, Canada.
⁷ Division of Cardiology, Unity Health, Department of Medicine, Temerty Faculty of Medicine, University of Toronto, Ontario, Canada.

PMID: 41856454
DOI: 10.1016/j.resuscitation.2026.111061

Abstract

Background: Although pad position influences current delivery, the relationship between transthoracic current, pad position, and shock efficacy during external defibrillation for refractory ventricular (VF) has not been examined.

Objective: To assess the relationship between pad position, current delivery and return of spontaneous circulation (ROSC) among patients enrolled in the Double Sequential External Defibrillation for Refractory VF (DOSE VF) trial.

Methods: We conducted a secondary, per-protocol analysis of patients enrolled in DOSE VF. Transthoracic current was calculated for the first six shocks using defibrillator-derived measures of shock energy and impedance, applying manufacturer-provided formulas. Current delivery was compared across standard anterolateral (AL), vector-change (VC) anteroposterior (AP), and double sequential external defibrillation (DSED; AL + AP) shocks. Multivariable logistic regression and generalized estimating equation (GEE) models were used to examine associations between current delivery, pad position and ROSC.

Results: 342 patients were included (mean age 63.6 years; 85% male), contributing 849 interventional shocks (51.6% standard, 25.4% VC and 22.9% DSED). Mean current was significantly greater for AP shocks in both VC (19.6 A) and DSED (19.2 A), compared with standard AL (16.6 A) and DSED AL shocks (17.3 A) (P < 0.001). In GEE modeling, AP positioning was independently associated with ROSC compared to AL positioning (aOR 2.01; 95% CI: 1.12-3.59). Delivered current was not associated with ROSC.

Conclusions: AP delivered higher current than AL positioning; however, pad position rather than delivered current was independently associated with ROSC. These findings suggest the additional AP pad position may be a key mechanistic contributor to the benefit of VC and DSED.

Keywords: Cardiac arrest; Cardiopulmonary resuscitation; Defibrillation; Double sequential external defibrillation; Resuscitation; Vector change defibrillation.

Publication types

Randomized Controlled Trial
Multicenter Study

MeSH terms

Aged
Defibrillators
Electric Countershock* / instrumentation
Electric Countershock* / methods
Female
Humans
Male
Middle Aged
Patient Positioning* / methods
Return of Spontaneous Circulation* / physiology
Ventricular Fibrillation* / physiopathology
Ventricular Fibrillation* / therapy