Long-term survival after cardiac arrest improves over time

American Heart Association
Tuesday, 26 August 2003

The average survival time for people resuscitated and discharged from the hospital after out-of-hospital sudden cardiac arrest (SCA) improved substantially over time, according to 25 years of data reported in today's rapid access issue of Circulation: Journal of the American Heart Association.

Researchers studied data of 2,035 patients who were discharged from hospitals in King County, Washington, between 1976 and 2001 after being resuscitated from SCA. Comparing intervals of about five years each, the researchers found an average drop in total deaths of 13 percent for each successive time period since 1976-1980 and a 21 percent drop in heart-related deaths for each period, says Thomas Rea, M.D., M.P.H., an epidemiologist at the division of emergency medical services, public health for Seattle and King County, Washington, and an assistant professor of medicine at the University of Washington in Seattle.

During SCA, the heart often suddenly begins beating erratically and cannot pump blood to the rest of the body, causing death within minutes. If patients get cardiopulmonary resuscitation (CPR) and an electrical shock to the heart from an automated external defibrillator (AED) or manual defibrillator soon after the arrest, survival rates increase significantly, he says. Each year an estimated hundreds of thousands of U.S. residents are thought to die from SCA, about half of all deaths from coronary heart disease.

"Our findings suggest that something is occurring over time that is producing a better prognosis for these patients," Rea says, adding that the study cannot pinpoint the cause of improved survival during the past quarter century.

"I think it's likely to be a complex set of factors that may be different for different people," he says. Those factors include behavioral improvements like stopping smoking and improving diet over time; advances in drug treatment for arrhythmia, high blood pressure and high cholesterol; and interventions such as implantable defibrillators and techniques to reopen or bypass clogged heart arteries.

"Our analysis suggests that these improvements have not been an all-at-once thing but have been a cumulative process that has led to an overall survival benefit that translates to an approximate 40 percent reduction in the risk of death from all causes and a nearly 60 percent reduction in heart disease death for the 1995-2001 period compared to the 1976-1980 period," Rea says. However, even in the final time period (1995-2001), heart disease still caused the majority of deaths, suggesting there is still room for continued improvement, Rea says.

Co-authors are Matthew Crouthamel, B.A.; Mickey S. Eisenberg, M.D., Ph.D.; Linda J. Becker, M.A.; and Ann R. Lima, B.S.

For more information, or to contact American Heart Association, see their website at: www.americanheart.org