Incidence and survival rate of bystander-witnessed out-of-hospital cardiac arrest with cardiac etiology in Osaka, Japan: a population-based study according to the Utstein style.

Abstract

To clarify the incidence and survival rate of bystander-witnessed out-of-hospital cardiac arrests (OHCA) with cardiac etiology in Osaka Prefecture, Japan, with a population of nearly 9 million according to the Utstein style. 5047 consecutive OHCA cases were treated by ambulance personnel during the 12-month period starting since 1 May 1998. 974 cases were considered to be bystander-witnessed OHCA with cardiac etiology and analyzed using the Utstein style. Of the 974 cases (100%), 50 cases (5.1%) survived after 1 month and 28 (2.9%) of them after 1 year. The Ventricular fibrillation (VF)/ventricular tachycardia (VT) group comprised 164 (16.8%) cases and there were statistically differences between the two groups as below (the VF/VT group vs. the non-VF/VT group): gender (male: 76.8 vs. 60.7%), age (61.7+/-14.7 vs. 68.7+/-17.1), history of ischemic heart disease (IHD) (30.5 vs. 15.3%), performance rate of bystander cardiopulmonary resuscitation (CPR) (34.1 vs. 21.4%) and time interval between receipt of an emergency call and arrival at the scene (5.5+/-2.9 vs. 6.0+/-2.9 min). The incidence of bystander-witnessed (OHCA) with cardiac etiology and VF or VT were remarkably low compared with those reported by other studies conducted in some areas of Europe or the USA.