Saturday, September 9 2006 12:25 Hrs (IST) - World Time -

Berlin: Symptoms may appear two hours before a person gets a cardiac arrest and learning to recognise these warnings may help scientists to prevent cardiac death, a new study has found.

More than 330,000 people die each year from heart disease before reaching hospital, or in an emergency room. Most of these deaths are caused by sudden cardiac arrest, according to the American Heart Association.

In the study, Dirk Muller and other researchers at the University of Berlin examined 406 cases of cardiac arrest out of the more than 5,000 rescue missions performed by doctors at a mobile intensive care unit here, reported the online edition of the health magazine WebMD.

The results showed 72 percent of the cardiac arrests occurred at home and bystanders witnessed 67 percent.

Researchers collected information on symptoms preceding cardiac arrest on 323 of the 406 cases.

The most common warning symptom was chest pain lasting from 20 minutes to 10 hours and 30 minutes before the cardiac arrest, or a median of two hours. Chest pain occurred in 25 percent of the cardiac arrests witnessed by others, the researchers said.

Breathlessness for 10 minutes was reported in 17 percent of witnessed cardiac arrests, nausea or vomiting for 90 minutes before the arrest in seven percent. Other common symptoms were dizziness or fainting.

The study suggests people often develop symptoms of cardiac arrest, like chest pain or breathlessness, around two hours beforehand. In addition, up to two-thirds of sudden cardiac death victims have a history of heart disease that puts them at risk for cardiac arrest.

Researchers say learning to recognise these warning signs of cardiac arrest may offer a window of opportunity to prevent sudden cardiac death.

"Family members and care givers of people with heart disease and at increased risk should be trained to recognise symptoms and perform CPR (cardiopulmonary resuscitation) to reduce the likelihood of death from cardiac arrest," a researcher said.