Resumption of Chest Compressions Following Successful Defibrillation and Risk for Recurrence of Ventricular Fibrillation in Out-Of-Hospital Cardiac Arrest
Background—Prior investigation of out-of-hospital cardiac arrest (OHCA) has raised the concern that ventricular fibrillation (VF) recurrence may be triggered by chest compression (CC) resumption. We investigated predictors of VF recurrence after defibrillation, including timing of CC resumption.
Methods and Results—Patients with witnessed OHCA and initial rhythm of VF from an Utstein-style database were analyzed. For each shock that defibrillated VF, CC resumption and VF recurrence times were determined. Shocks were classified according to post-shock rhythm. Factors (age, gender, time from dispatch to monitor/defibrillator application, and CC resumption) that could predict VF recurrence were analyzed. CC resumption was categorized into groups: CC1: 1-5 sec, CC2:6-10 sec, CC3: 11-30 sec, and CC4: >30 sec. 88 subjects were analyzed, with a total of 285 shocks, with 226 shocks that achieved asystole (N=102), organized rhythm (OR) (N=120) or monomorphic ventricular tachycardia (N=4). Following a successful shock, CC resumption occurred at a median [interquartile range] = 8 [5, 18] sec. VF recurred after 166 shocks (74%), and recurred within 30 sec in 69 shocks. There was no significant relationship between VF recurrence and factors analyzed including CC resumption time, nor stratified by post-shock rhythm. The hazard ratios for VF recurrence within 30 sec for later CC groups (CC2, CC3 and CC4) relative to early CC resumption (CC1) were: HR(CC2)=1.05 (p=0.9), HR(CC3)=1.75 (p=0.1), HR(CC4)=0.67 (p=0.4).
Conclusions—VF recurrence within 30 sec of a defibrillatory shock was not dependent upon timing of CC resumption in patients with witnessed arrest and initial rhythm of VF.
- Received January 27, 2014.
- Revision received May 19, 2014.
- Accepted June 2, 2014.