Ventricular fibrillation in Rochester, Minnesota: experience over 18 years

Survival following out-of-hospital cardiac arrest (OHCA) continues to be disappointingly low world-wide, despite advances in technology and international guidelines for resuscitation. Few cities or emergency medical service (EMS) agencies report patient outcomes after OHCA. Among those who do, survival from witnessed VF ranges from 7.7% to 39.9%, with only a few cities reporting rates higher than this. We report outcomes and incidence of VF OHCA over 18 years in a medium-sized city incorporating an aggressive approach to OHCA.

The city, which increased in population over the study period from 70,000 to 100,000 persons, utilizes an emergency response system which dispatches defibrillator-equipped police, fire-rescue and ambulance personnel simultaneously. Police and fire-rescue personnel are equipped with automated external defibrillators (AEDs). Advanced life-support is provided as needed by paramedics.

There were 454 arrests during the study period attributed to a cardiac cause. Of 271 bystander-witnessed arrests, 203 (74.9%) were in VF and 94 (46.3%) were discharged. Average time from 9-1-1 call to shock was relatively short: mean 6.5 min (S.D. 2.5 min). In a multivariable model, the interval from call to shock was strongly associated with neurologically intact survival (OR 0.72, 95% CI: 0.61-0.84 for each additional minute). The age- and sex-adjusted incidence of EMS-treated VF OHCA significantly (p<0.001) declined over the study period: 1991-1999: 37.9/100,000 (95% CI: 31.8-44.0), 2000-2008: 17.8/100,000 (95% CI: 14.4-21.2).

High survival from witnessed VF OHCA (46.3%) was achieved during the study period. Rapid response, and therefore rapid defibrillation, was the major contributor to survival.