Context Recent reports from 2 European cities and an earlier observation from
Seattle, Wash, suggest that the number of patients treated for out-of-hospital
ventricular fibrillation (VF) has declined.
Objective To analyze the incidence of cardiac arrest and to examine relationships
among incidence, sex, race, age, and first identified cardiac rhythm in Seattle.
Design, Setting, and Patients Population-based study of all cardiac arrest cases with presumed cardiac
etiology who received advanced life support from Seattle Fire Department emergency
medical services during specified periods between 1979 and 2000. 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.
Main Outcome Measures Changes in incidence of cardiac arrest and initial recorded cardiac
Results 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.
Conclusion We observed a major decline in the incidence of out-of-hospital VF and
in all cases of treated cardiac arrest presumably due to heart disease in
Seattle. These changes likely reflect the national decline in coronary heart