A defibrillator training session in a Chicago public school in 2003. (Aynsley Floyd/AP)

This post has been updated.

Cardiac arrest is "an immense and sustained public health problem" that kills too many people who could be saved by increasing public knowledge of CPR and improving the emergency response system, a panel of experts reported Tuesday.

Nearly 600,000 people -- 1,600 a day -- suffer sudden heart stoppages every year, about 400,000 of them outside hospitals. Less than 6 percent of victims survive cardiac arrests outside hospitals. Of the 200,000 cardiac arrests that occur in hospitals, 24 percent of victims survive, according to a panel of the independent Institute of Medicine, the health arm of the National Academy of Sciences. Survival rates vary widely between communities in the United States.

Yet less than 3 percent of the U.S. population receives training in cardiopulmonary resuscitation annually, and the system for providing immediate attention and racing a victim to a hospital needs  improvement, the experts concluded.

[Sudden cardiac arrest is quite rare during exercise]

"The ability to consistently deliver timely interventions and high-quality care is less than impressive," they wrote in a report released Tuesday morning. "The result is too many people dying from cardiac arrest."

Sudden cardiac arrest is not a heart attack — a blocked artery that cuts off the blood supply to the heart muscle and is much more survivable. Cardiac arrest is a disturbance of the electrical or mechanical activity that governs the ordered pumping of blood from the heart, often leading to sudden collapse without warning.

"Cardiac arrest can strike anyone at any time," Robert Graham, chairman of the panel and a faculty member at the Milken Institute School of Public Health at George Washington University, said at a presentation on the report Tuesday.

Improvements in the system of addressing cardiac arrest are plagued by inadequate data; the numbers presented in the report, which is the most comprehensive assessment of the problem to date, are estimates, panelists said. In addition, spending on research is just a fraction of the sum devoted to other diseases, including other heart conditions, said Lance Becker, an emergency physician who is part of the University of Pennsylvania Health System.

And survival sometimes can depend merely on where a cardiac arrest occurs, because the quality of response and care varies widely from location to location. One study of ten North American sites showed that survival rates for out-of-hospital arrests range from 7.7 percent to 39.9 percent. Seattle and King County, Wash., achieved 62 percent survival for a specific type of cardiac arrest if someone witnesses the collapse, compared with less than 10 percent in other places.

[Mobile app improves CPR rates in cardiac arrests]

"Effective treatments for specific types of cardiac arrest are known and, if these treatments were more efficiently implemented on a broader basis, could avoid needless deaths and disability each year," the panel wrote.

But only about 46 percent of cardiac arrests outside hospitals are seen by another person, and 70 percent of them do not respond to electrical shock, the report notes, often because someone with a defibrillator arrives too late.

Bruce Lindsay, section chief for cardiac electrophysiology and pacing at the Cleveland Clinic, endorsed the report's conclusion that the way to save more lives is to engage more bystanders in performing CPR.

"If you could start training people at a young age to think about this and to do an effective job, it would make a difference," said Lindsay, who was not involved in the preparation of the report. More money for research might unearth warning signs of cardiac arrest that aren't apparent now, he added.

The panel recommended enhancing the performance of emergency medical systems, particularly by emphasizing CPR that is assisted by dispatchers; improving resuscitation and care inside hospitals; and training more members of the public in the use of CPR and automated external defibrillators, the shock devices that can be found in airports, gyms and other locations.

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