Researchers to Study More Patients to Find Genetic Markers for Sudden Death

08/16/00    Portland, Ore.

Heart Analysis Shows Many Die with No Signs.

Some people who experience sudden cardiac death may have had no previous heart symptoms and their problem may not have been detectable to a cardiologist, says a new study published in Circulation, the journal of the American Heart Association. In a first-ever cadaveric analysis of people whose hearts suddenly stopped, researchers at Oregon Health Sciences University and The Edwards Registry in St. Paul, Minn. found that about a third of all sudden cardiac death patients had either normal hearts or nonspecific abnormalities that would not indicate a problem.

"What this tells us is we need a better way to diagnose patients early to determine if they may have a heart problem, then get them treatment right away," said Sumeet Chugh, M.D., assistant professor of cardiology in the OHSU School of Medicine and principal investigator of the study.

For the analysis, Chugh and his colleagues examined 270 hearts from patients who had died of sudden cardiac death. They also collected data on the circumstances of the patients' death and reviewed their medical records. In 95 percent of the cases, the hearts showed some structural abnormality, such as coronary artery disease, aortic valve malformations, atrial septal defects or left ventricular hypertrophy. While about two-thirds of these cases could have been treated by surgery or medications, in another 30 percent of the cases the cause of death may or may not have been related to the abnormalities.

The analysis also found that in five percent of overall cases, the patients' hearts were structurally normal, and about half of those patients had never reported a symptom of heart problems. "These people may have had a genetic condition that, when combined with another trigger such as obesity, drug use or epilepsy caused their death. For cases like these, we need to be able to find genetic markers to identify patients with these susceptibilities."

Chugh is now working with colleagues to design a study using live patients to identify unknown heart problems. "With information from the Human Genome Project now publicly available, we can use microarray technology to help identify these genetic markers," he said. Chugh hopes to develop a registry of heart cases in Oregon to use this state as a model for studying the causes of sudden cardiac death.