DALLAS, Jan. 20 -- Sudden cardiac arrest risk goes up 50 percent for individuals whose parent, brother or sister has had heart attack or sudden cardiac arrest, according to a report in today's Circulation: Journal of the American Heart Association.
"Our findings are in agreement with many studies which have clearly demonstrated a familial clustering for heart disease," says the study's lead author Yechiel Friedlander, Ph.D., at the Hebrew University of Jerusalem, Israel, and colleagues at the University of Washington, Seattle.
However, the study also finds that an individual's genetic susceptibility to sudden cardiac arrest is not explained just by such traditional heart disease risk factors as diabetes, high blood pressure and high cholesterol. Like heart disease, these risk factors tend to run in families.
"Sudden cardiac arrest risk associated with family history was independent of other risk factors," says Friedlander. "This indicates that traditional heart disease risk factors account for only a small part of the clustering and does not explain the familial patterns seen in our study."
Cardiac arrest occurs when the heart suddenly stops beating, due to an abnormal life-threatening heartbeat, called ventricular fibrillation. In contrast, heart attack occurs when blockages, from blood clots or fatty buildup called plaque, in the blood vessels prevent blood flow to the heart.
The researchers compared family histories of cardiac arrest victims with those of healthy individuals with similar age, sex and other physical characteristics. The study was limited to victims of sudden cardiac arrest who did not have a prior history of heart disease and whose cardiac arrest was not secondary to trauma or drug overdose. Data were gathered via interviews with 357 spouses of cardiac arrest victims and 576 spouses of healthy individuals.