Association Between Converting Asystole From Initial Shockable ECG Rhythm Before Extracorporeal Cardiopulmonary Resuscitation and Outcome

Initial electrocardiogram (ECG) rhythm is a predictor of outcomes in out-of-hospital cardiac arrest (OHCA) in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR). However, ECG rhythm often changes before ECPR, and the consequence of this change remains unclear. This study aimed to assess the relationship between the conversion of ECG rhythm from initial shockable rhythm before ECPR and mortality. This was a retrospective cohort study of OHCA patients with initial shockable rhythm who underwent ECPR between January 2010 and September 2020. Patients were classified into two groups: asystole (patients whose ECG rhythm converted to asystole at any time before initiating ECPR) and non-asystole (patients whose ECG rhythm did not convert to asystole at any time before initiating ECPR) groups. The primary outcome was in-hospital mortality. A total of 102 patients were included in the study; in-hospital mortality rate was 46.1% (n = 47) and 76 (74.5%) patients had unfavorable neurological outcomes (Cerebral Performance Category: 3-5). There were 33 and 69 patients in the asystole and non-asystole groups, respectively. The mortality rates in the asystole and non-asystole groups were 69.7% and 34.8%, respectively (P = 0.001). On multivariable analysis, the asystole group showed a significant association with mortality (odds ratio, 5.42; 95% confidence interval, 2.11-15.36; P