Major decline in the incidence of out-of-hospital in ventricular fibrillation reported

Cobb et al. instigated this population-based trial to further verfy recent reports from 2 European cities and an earlier observation from Seattle, Washington, that suggest that the number of patients treated for out-of-hospital ventricular fibrillation (VF) has declined. The investigators analysed the incidence of cardiac arrest and examined relationships among incidence, sex, race, age, and first identified cardiac rhythm in Seattle.United States Census data for Seattle in 1980, 1990, and 2000 were used to determine incidence rates for treated cardiac arrest with adjustments for age and sex.The primary end point was rate of change in incidence of cardiac arrest and initial recorded cardiac rhythm."The adjusted annual incidence of cardiac arrest with VF as the first identified rhythm decreased by about 56% from 1980 to 2000 (from 0.85 to 0.38 per 1000; relative risk [RR], 0.44; 95% confidence interval [CI], 0.37-0.53). Similar reductions occurred in blacks (54%; RR, 0.45; 95% CI, 0.26-0.79) and whites (53%; RR, 0.47; 95% CI, 0.38-0.58) and was most evident in men (57%; RR, 0.43; 95% CI, 0.35-0.53), in whom the baseline incidence was relatively high. When all treated arrests with presumed cardiac etiology were considered, that incidence decreased by 43% (RR, 0.58; 95% CI, 0.49-0.67) in men but negligibly in women, for whom a relatively low incidence of VF also declined but was offset by more cases with asystole or pulseless electrical activity."1Reference...