Incidence of Ventricular Fibrillation in Patients With Out-of-Hospital Cardiac Arrest in Japan : Survey of Survivors After Out-of-Hospital Cardiac Arrest in Kanto Area (SOS-KANTO)

Background Although there is a close connection between emergency medical services (EMS) system and the outcome of out-of-hospital ventricular fibrillation (VF), few data are available regarding the situation in Japan. Methods and Results A prospective multicenter study of out-of-hospital cardiac arrest was conducted according to the Utstein guidelines. A total of 4,383 patients who were given cardiopulmonary resuscitation (CPR) by EMS personnel for out-of-hospital cardiac arrest were enrolled. The proportion of VF or pulseless ventricular tachycardia (VT) as the first cardiac rhythm after cardiac arrest was 16.2% with a mean call-to-initial-recorded-electrocardiogram (ECG) interval of 11.1min. In a subgroup of patients with witnessed collapse, the predicted incidence of VF or pulseless VT was 62.7% at the time of cardiac arrest, and the decline accelerated with every minute that the collapse-to-initial ECG interval was delayed. Multivariate analysis showed that the odds ratio for VF or pulseless VT after collapse-to-initial ECG interval was 0.91 (95% confidence interval (CI), 0.89-0.94, p<0.001), and 1.54 (95%CI, 1.24-1.97, p<0.001) after bystander CPR. Conclusions In Japan, VF occurred in 63% of cases at the time of cardiac arrest and the performance of bystander CPR appeared to prolong VF.