New research, designed to see whether automated external defibrillators (AED) could extend the lives of people who had suffered a specific type of heart attack, has concluded that they do not increase the chances of survival better than CPR.

An AED is meant to shock a quivering heart back to a healthy beat during cardiac arrest. A heart that has short-circuited and quivers can be restarted only by such a shock. Chest compressions buy time until a defibrillator arrives.

Dr. Gust Bardy of the Seattle Institute of Cardiac Research and colleagues followed 7,001 people at moderate risk of sudden cardiac arrest in a 37-month trial. Half of the participants had defibrillators put in their homes, while the other half got standard instructions to call for emergency help if a second heart attack occurred.

The researchers discovered that the death rate for both groups was just about the same – 222 of the people given defibrillators and 228 of those not given the devices.

“There was no mortality benefit,” Dr Bardy said, according to Reuters.

Dr. Bardi added that any discussion with a doctor after a heart attack should include advice about carefully taking any medications that are prescribed and about other measures needed to prevent cardiac arrest.

“The best way to survive a cardiac arrest is not have it in the first place. This is accomplished through diet, exercise, non-smoking and access to good medical care for conditions like high blood pressure prior to a heart attack,” Arthur Kellermann of the Emory School of Medicine in Atlanta said, according to the USA Today.

Defibrillators for use at home cost between $1,200 and $2,000 per unit. Defibrillators used in the study were manufactured by Philips Medical Systems, a unit of Royal Philips Electronics, which are the only defibrillators available without a prescription. Other companies, including Zoll Medical and Cardiac Science, make defibrillators that can be purchased with a prescription.

Dr. David Callans of the University of Pennsylvania wrote a commentary on the findings saying, “In light of the study findings and the high cost of the devices, future efforts should turn toward education, modification of risk factors and other methods for primary prevention of heart disease.”

However, there are still doctors who support home defibrillators. “Early defibrillation offers the best chance for survival. My point is that there may be a role for defibrillator as part of a plan developed by your physician on an individual basis,” said Dr. Robert Femia, chairperson of emergency medicine at Lenox Hill Hospital in New York City.

Cardiac arrest strikes about 125,000 Americans each year in their homes and 40,000 in public settings outside of hospitals. Cardiac arrest seems to be more dangerous than a heart attack, which involves a restriction of blood flow to the heart’s muscle and is often not fatal. According to some studies, the survival rate from cardiac arrest in the home is as low as 2 percent.

The findings of the study were presented Tuesday at the American College of Cardiology annual meeting in Chicago and were published in the April 1 online edition of the New England Journal of Medicine. The findings are also expected to be published in April 24 print issue of the journal.