Double Sequential External Defibrillation and VC Defibrillation Increase Survival in Cardiac Arrest Patients: Study

"Double sequential external defibrillation (DSED) and vector change (VC) defibrillation reduced the duration of VF compared to standard shocks (83 & 98 seconds versus 108 seconds, respectively). DSED demonstrated the highest rates of return of spontaneous circulation (17.6% versus 5.3%) and survival to hospital discharge (10.2% versus 3.5%) compared to standard shocks, indicating their potential to improve cardiac arrest outcomes," the researchers reported.

Double sequential external defibrillation, a technique that delivers two defibrillation shocks in quick succession from separate devices, demonstrated the most promising results. Survival following out-of-hospital cardiac arrest (OHCA) is closely linked to the duration of ventricular fibrillation. However, the effect of vector change defibrillation and DSED on VF duration has not been investigated thoroughly. Considering this, Sheldon Cheskes, Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada, and colleagues aimed to evaluate the impact of VC and DSED on VF duration and defibrillation effectiveness.

For this purpose, the researchers conducted a secondary analysis of patients enrolled in the Double Sequential External Defibrillation for Refractory VF RCT. They evaluated ECG recordings following each shock, measuring VF duration (median, IQR) and assessing shock outcomes. To compare VF duration among different groups, the Kruskal-Wallis test was applied, followed by post-hoc pairwise comparisons using Dunn’s test with Bonferroni correction. Shock outcomes were analyzed using chi-square tests.

The study revealed the following findings:

• One thousand eight hundred forty-two shocks were analyzed among 342 patients, including 834 shocks following three failed standard shocks (429 standard, 218 VC, 187 DSED).
• Median VF duration was significantly shorter with DSED (83 [0, 120] s) and VC (98 [0, 120] s) compared to standard shocks (108 [38, 120] s).
• The rate of ROSC was higher for DSED (17.6%) and VC (14.2%) compared to standard shocks (5.3%).
• Survival to hospital discharge was greater for DSED (10.2%) and VC (7.3%) than for standard shocks (3.5%).
• The proportion of shocks in which VF was not terminated was significantly lower for DSED (29.9%) than standard shocks (40.6%).

"In the DOSE VF RCT, patients who received DSED and VC shocks experienced a shorter VF duration than those given standard shocks. Both DSED and VC shocks were significantly more effective in achieving ROSC and improving survival to hospital discharge," the researchers wrote.

"The reduced VF duration observed with these alternative defibrillation strategies may help explain the survival benefits seen in the trial," they concluded.

Reference:

Cheskes, S., Drennan, I. R., Turner, L., Pandit, S. V., Walker, R. G., & Dorian, P. (2025). The impact of alternate defibrillation strategies on time in ventricular fibrillation. Resuscitation, 110549. https://doi.org/10.1016/j.resuscitation.2025.110549