A team of cardiologists at the University of Rochester Medical Center has won a four-year, $2.3 million grant from the National Institutes of Health (NIH) to continue its study of a cardiac condition that places teens at risk for sudden death. With the latest award, the team will have received continuous NIH funding for 23 years - one of the longest, continuous, investigator-initiated research projects at the University of Rochester.
Cardiac arrhythmias are electrical malfunctions that throw the heart out of rhythm, causing many of the 330,000 sudden cardiac deaths each year in the United States. Most fatal arrhythmias occur in aging patients when scar tissue left by a heart attack interferes with the heart's electrical system. As many as 1,000 deaths each year, however, are caused by Long QT Syndrome (LQTS), the focus of the long-running grant renewal. LQTS occurs mostly in teens with otherwise healthy hearts. Research into this infrequently occurring medical condition has provided insights into much more common, post-heart attack arrhythmias.
The QT interval is part of the heart's electrical signature as recorded by an electrocardiogram (ECG). It represents the time it takes for the heart's lower chambers to "electrically recover" after each heartbeat. In LQTS patients, the QT electrical recovery time is prolonged, which makes the heart more susceptible to fatal arrhythmias. The condition may go unnoticed until sports, strong emotions or even loud noises knock the heart out of rhythm, causing loss of pulse and rapid, chaotic heart rhythm with loss of consciousness (syncope). In some cases, the dangerous heart rhythm stops on its own, but in others it deteriorates into a fatal rhythm (ventricular fibrillation). Sudden death will then occur if the heart is not restarted with a defibrillator. Some families have lost one or more children before realizing that their family has an inherited heart condition.