Dr. Tadeusz Petelenz, a researcher in Poland, said the technique, called cough CPR, forces blood to the brain while the heart is starting to fail and keeps patients conscious long enough to call for help. It may also rectify their heart rhythm, he told a meeting of the European Society of Cardiology.

He recommended Cough CPR be taught to the public, but other experts said while the concept is provocative, it needs more study.

Every year about 300,000 people in the United States die from sudden cardiac death.

Most of the time, the culprit is a type of heart attack brought on by a sudden problem with the heart's rhythm _ ventricular fibrillation.

In three-quarters of cases, the attack happens at home, often when the victim is alone. Circulation stops, the victim faints and brain damage occurs within minutes. Death usually follows in about 15 minutes.

``Since the onset of the loss of consciousness is very rapid, they usually don't have enough time to call for help,'' said Petelenz, a professor at the Silesian Medical School in Katowice, Poland. ``However, if victims could maintain consciousness until circulation is restored or help arrives their chances of survival would greatly increase.''

Electric shock to the heart, known as defibrillation, is the only real treatment. Cardiopulmonary resuscitation, or CPR, can keep the brain and heart viable for about 10 minutes, long enough for an ambulance to bring a defibrillator.

Only a fraction of heart attack victims get CPR from a bystander, and few of those will receive the shock treatment before suffering irreversible brain damage.

The rate of survival without serious brain damage is about 10 percent, said Dr. Leo Bossaert, executive director of the European Resuscitation Council.

Petelenz's idea is not entirely new. Doctors sometimes ask heart disease patients undergoing angiograms to cough rhythmically and forcefully to get their circulation going.

Bossaert, a professor at the University Hospital in Antwerp, Belgium, said coughing probably would not be harmful, but it is far too early to recommend people try it at home. The symptoms preceding an attack can be hard for people to recognize in the 30 seconds before they lose consciousness, he said.

Dr. Marten Rosenquist, professor of cardiology at the Karolinska Institute in Stockholm, Sweden, and an expert in heart beat abnormalities, said the concept is interesting but that Petelenz showed no evidence his patients actually had arrhythmias.

Petelenz presented results from a study he conducted on 115 people who had previously fainted or come close to losing consciousness because of various heart problems. They were taught how to recognize the symptoms _ sudden dizziness and weakness, shortness of breath, sudden sweating and blurred vision _ and then taught the proper coughing technique.

The patients used the cough in 365 instances where they thought they were about to faint. The symptoms disappeared in 292 cases and medical attention was required in only 73 cases.

``All patients survived until the follow-up therapy, which included 45 pacemaker implantations, 55 heart surgeries and 15 (drug) interventions,'' Petelenz said.