TUESDAY, March 18, 2003 (HealthDayNews) -- When an electric jolt is not enough to restart a stopped heart, cardiopulmonary resuscitation -- pushing hard on the chest and breathing into the mouth -- may save some lives, a Norwegian study finds.
Cardiopulmonary resuscitation (CPR) plus the electric shock called defibrillation increased survival rates, but only when the emergency response time to ventricular fibrillation, a heart-stopping condition, was five minutes or longer, reports a group led by Dr. Lars Wik of the Ulleval University Hospital in Oslo.
The finding appears in the March 19 issue of the Journal of the American Medical Association.
The chance of survival is notoriously low when the heart begins to fibrillate -- fluttering uselessly instead of pumping blood to the body. Minutes count enormously. The standard emergency treatment is defibrillation, a shock to restore normal heartbeat. In this study, some patients were given CPR as well.
Overall, there was no significant difference in the one-year survival rate for patients who got only defibrillation and those who also got CPR. But there was a significant difference in the one-year survival rate in the two groups when treatments started later than five minutes after the problem was reported -- 20 percent of those getting the combined therapy survived, compared to 4 percent of those getting only defibrillation.
CPR was given in different ways. Some patients got three minutes of CPR before defibrillation. Others were given one minute of CPR if the attempt to restart the heart by defibrillation failed.
Although the study says these results require confirmation in additional randomized trials, the study results have changed the way some paramedics respond to all reports of ventricular fibrillation, Wik says. "Five minutes is probably not the cutoff time," he says. "We have introduced the CPR first strategy for all cardiac arrest patients."
The higher rate of survival "may be due to improvement of the blood oxygenation and metabolites around the heart," Wik says.
Non-medical people may confuse ventricular fibrillation with a myocardial infarct, which happens when a heart artery is blocked or burst. Emergency teams can easily tell the difference, Wik explains. "Cardiac arrest patients do not talk," he says. "Myocardial infarction patients do talk. If they are in cardiac arrest, they do not talk any more."
The Norwegian trial was prompted, in part, by results of a study reported four years ago by a group led by Dr. Leonard A. Cobb of the University of Washington School of Medicine. In that study, adding CPR to defibrillation increased survival from 24 percent to 30 percent, with the increase concentrated in patients for whom treatment was started four minutes or later after the first report. However, that study was not conducted under the "gold standard" rules for medical research, with patients selected at random to receive one treatment or the other.
An accompanying editorial to the current report by Dr. Terence D. Valenzuela of the University of Arizona department of emergency medicine says the Norwegian study has "potential clinical importance" because its results "are remarkably similar to those reported by Cobb." But more carefully controlled studies are needed before the CPR-plus-defibrillation treatment can be widely adopted, Valenzuela says.
More information
More information about ventricular fibrillation is given by the American Heart Association. For more on arrhytmias, go to the National Heart, Lung, and Blood Institute.
