Incidence and Characteristics of Ventricular Fibrillation in Bystander-witnessed Out-of-hospital Cardiac Arrest with Cardiac Etiology in the City of Sendai, Japan

Methods and results: We analyzed Utstein-style data in Sendai City (population 1,020,000), Japan from January 2002 to March 2004. The incidence of OHCA overall was 62.3/100,000/year. The incidence of the bystander-witnessed VF was 2.5/100,000/year. In younger patients (20-65 years of age), the percentage of VF was 52% when cardiac origin was presumed by bystander witness, and ECG was recorded within 10 minutes from the collapse. In older patients (over 65 years of age), however, the percentage of VF was 21% when they were bystander-witnessed, and ECG was recorded within 10 minutes from the collapse. No VF was reported when the ECG was recorded more than 15 minutes after the collapse. The thirty-day survival rate was 21% in the bystander-witnessed VF cases with cardiac etiology, but 0% in the non-VF cases. The bystander CPR was significantly associated with improved 30-day survival rate. Conclusion: Younger age, male gender, and shorter collapse-to-ECG time are significantly associated with the appearance of VF in bystander-witnessed OHCA with cardiac etiology. Bystander CPR was significantly associated with the improvement in prognosis of those VF patients.