Simple test signals high risk after heart attack

By Karla Gale

NEW YORK (Reuters Health) - A simple two-in-one heart test may identify individuals who face the greatest risk after suffering a heart attack, cardiologists from Canada report.

By examining both the nervous system and the heart's electrical system - both of which are critical to the development of serious heart rhythm disturbances -- the cardiologists found they were better able to identify patients at highest risk of cardiac arrest or death, even years after a heart attack.

"This is important because past studies, focusing on a single test, failed to identify most people at risk," Dr. Derek V. Exner, a heart rhythm specialist and an associate professor at the University of Calgary's Libin Cardiovascular Institute of Alberta, noted in a written statement.

"We developed a simple method of identifying approximately twice as many people at risk. That means we can potentially save more lives," Exner added.

The study involved 322 heart attack patients. Within 2 to 4 weeks of the heart attack, and again at 10 to 14 weeks, they performed a variety of tests to measure the status of both the nervous system and the heart's electrical system. They then tracked patients for an average of nearly four years. During this time, 30 patients died. There were 22 heart-related deaths and 7 resuscitated cardiac arrests.

At the 10- to 14-week mark, the presence of T-wave alternans (an abnormality in the heart's rhythm seen on a computer) and impaired heart rate turbulence (a measure of the heart's ability to adapt to change) reliably predicted a higher risk of cardiac arrest or death.

"The outlook is good for most heart attack survivors," Exner noted. "However, the one in five patients in our study who had abnormal tests were at high risk of serious problems."

"Close follow-up with a physician and the use of medications known to be beneficial after a heart attack -- aspirin, beta blockers, ACE inhibitors, and statins -- are very strongly recommended," the researcher added.

SOURCE: Journal of the American College of Cardiology, December 11, 2007.