January 27, 2011

Cardiac Arrest: Worse in Public Setting?

(Ivanhoe Newswire) -- A new study shows the frequency of a potentially deadly heart rhythm is lower among patients who suffer cardiac arrests at home than among those who have them in a public setting.

In order to find out if there was a link between the location of the cardiac arrest, the type of irregular heartbeat, and the probability of survival, Myron L. Weisfeldt, M.D., William Osler Professor of Medicine and Director of the Department of Medicine at the Johns Hopkins University School of Medicine and his colleagues, studied out-of-hospital cardiac arrest in adults in 10 communities. They assessed the frequencies of ventricular fibrillation (VF is a severely abnormal heart rhythm that can be deadly) and of survival to hospital discharge for arrests at home compared with arrests in public.

Of the 12,930 evaluated cardiac arrests, 2,042 happened in public, and 9,564 happened at home. For cardiac arrests at home, the incidence of VF was 25 percent when the arrest was witnessed by emergency medical services personnel, 35 percent when a bystander witnessed it, and 36 percent when a bystander applied an AED (automated external defibrillator). For cardiac arrests in public, the corresponding rates were 38 percent, 60 percent, and 79 percent.

"This finding adds strength to the argument for putting AEDs in public locations," the authors wrote.

The authors were able to conclude that regardless of whether cardiac arrests are witnessed by EMS personnel or bystanders and whether AEDs are applied by bystanders, the number of arrests with initial VFs is much greater in public settings than at home.

Source: The New England Journal of Medicine, January 26, 2011