Heart Unit Could Prevent Many Deaths, Study Says

Many of the 300,000 to 400,000 Americans who die each year after collapsing on the street or in their homes with cardiac arrest could be saved if there were more widespread use of a relatively simple electric-shocking device, a new study indicates.

The study, published today in the New England Journal of Medicine, found that use of the so-called automatic external defibrillator by Seattle firefighters nearly doubled the survival rate among people who experienced cardiac arrest outside of hospitals.

The improved survival rate was traced to a reduction in the time between the patient’s collapse and the delivery of a crucial electric shock to the heart--a reduction that is not possible when relying on trained paramedics using traditional equipment.

“If you can teach someone to read, you can teach them to use this device,” said Dr. W. Douglas Weaver, an associate professor of medicine at the University of Washington and the lead author of the study. “That’s the beauty of it.”

The study calls for police, ambulance attendants, firefighters and others who provide first aid to be trained and equipped to use the new device. It is already being tested in Los Angeles County and other urban and rural areas in California.

However, the author of an editorial that accompanies the article and endorses the recommendation cautioned in a telephone interview Wednesday that the device does not eliminate the need for cardiopulmonary resuscitation and advanced paramedic services.

“These . . . are not a solution in and of themselves,” said Dr. Jeremy N. Ruskin, director of the cardiac arrhythmia service at Massachusetts General Hospital in Boston. “There’s no way you’re going to have a defibrillator on every street corner.”

Cardiac arrest is caused by a loss of the normal electrical activity of the heart, which leads to a sudden change in the heart’s rhythm. That condition, called fibrillation, can be corrected with a quick electric shock to the heart.

If treated promptly, ventricular fibrillation is reversible and can be followed by many years of productive life, Ruskin noted. On average, experts say, defibrillation must be delivered within eight minutes of collapse in order to avert neurological damage.

Defibrillation is not useful in countering heart attack, which is brought on by blockage of the artery supplying blood to the heart. Cardiac arrest can be a first sign of heart disease, but those who die of it are not having a heart attack, Ruskin said.

Until recently, only paramedics underwent the extensive training required to interpret the findings of a defibrillator and deliver the electric shock. But paramedics usually arrive at the scene of an emergency later than firefighters or other “first responders.”

So Weaver’s group equipped certain Seattle fire districts with automatic external defibrillators, which a lay person can use with just four hours of training. The device can detect and interpret the rhythm of the heart, automatically delivering a shock if needed.

Weaver then compared the firefighters’ success rate with that of the traditional approach, in which firefighters administer CPR and wait for paramedics to arrive. The paramedics used traditional manual defibrillators, rather than the new automated ones.

Thirty percent of the 276 patients treated with automated defibrillation by the firefighters survived to hospital discharge. Only 19% of 228 patients survived when firefighters simply administered basic CPR, waiting for paramedics to deliver defibrillation.

“Its sole advantage will be the ability for it to be delivered to the victim faster than the manual defibrillator,” Ruskin said. “The critical issue is time--how fast you can defibrillate a victim.”

Not a Panacea

However, Ruskin warned that the new defibrillators are no panacea. He said there are three critical components in saving lives: widespread knowledge of CPR, prompt defibrillation and the availability of paramedics to administer drugs and other procedures if needed.

“This technique is very important and these devices work very well,” he said. “But . . . they’re only effective to the extent that they can be brought to the victim quickly. An automatic defibrillator that arrives on the scene 12 minutes after a patient has had cardiac arrest is not going to save lives.”

The Los Angeles County Fire Department began testing automatic external defibrillators in June in 15 of its 128 fire stations. The Los Angeles City Council also voted that month to begin to equip every one of its engines with the devices, each of which costs $4,000 to $7,000.

Dr. Bruce E. Haynes, director of the California Emergency Medical Services Authority, said there is growing interest in automatic external defibrillators in jurisdictions throughout the state, in part because of recent changes in state laws that encourage their use.

California last year became the first state in the country to permit defibrillation by so-called first-responder personnel. Advocates of defibrillation have urged that automated defibrillators be placed in offices, restaurants and other public places.