Genetic scores can predict which heart disease patients are at risk for sudden cardiac death

LOS ANGELES — Linked to roughly 300,000 U.S. deaths annually, sudden cardiac arrest (or sudden cardiac death) is an electrical malfunction in the heart that can lead to abrupt loss of cardiac functioning, breathing, and consciousness. Now, groundbreaking new research finds modern medicine may soon be capable of identifying patients at the highest risk for developing sudden cardiac death.

Study authors from the Smidt Heart Institute at Cedars-Sinai made use of a polygenic risk score that has previously proven successful in predicting coronary artery disease. This latest work, however, is the first ever to indicate that the very same risk score is also effective at identifying coronary artery disease patients who are most at risk of sudden cardiac death.

The findings reveal that coronary artery disease patients without severely impaired heart function display the highest polygenic risk score, which translates to a 77-percent increased risk of sudden cardiac death.

“In order to better predict and prevent sudden cardiac death, we must first understand the genetic connection between it and coronary artery disease,” says first study author Roopinder Sandhu, MD, MPH, an associate professor of cardiology, in a media release. “We found incorporating information from this genetic risk score improved our ability to predict sudden death beyond the contributions of other known risk markers. Most exciting, the genetics were able to identify patients where sudden death was more likely to limit their life expectancy.”

Patients may have no warning that something’s wrong

While heart attacks, or myocardial infarctions, are usually the result of clogged coronary arteries blocking the flow of blood to the heart, sudden cardiac death typically occurs because of sudden and erratic electrical activity that disrupts the pumping of the heart. In many cases, the patient has little or no warning at all. Sudden cardiac arrest can result in death within minutes if the patient does not receive resuscitation quickly.

Coronary artery disease is the most common underlying contributor to sudden cardiac death. According to Dr. Sandhu, this study may one day help more efficiently identify patients with the most to gain from lifesaving therapies like a defibrillator.

Today, the vast majority of sudden cardiac deaths (70%) occur in people who don’t actually meet the official guidelines for prevention with defibrillator therapy. This represents a two-fold medical error; not only are doctors neglecting the patients most at risk of sudden cardiac death, but most defibrillators are going to advanced heart disease patients. Unfortunately, these individuals are much more unlikely to reap the health benefits of a defibrillator due to their limited life expectancy.

This work is based on data provided by the National Institutes of Health-sponsored PRE-DETERMINE observational study. That project set out to more accurately identify those at an elevated risk of sudden cardiac death among the greater population of coronary artery disease patients who do not have advanced heart disease.

“This study indicates there is opportunity to identify patients at highest risk for sudden cardiac death, and then offering meaningful, preventative treatment solutions like a defibrillator. Based on our pivotal research, we now have the foundation to achieve this,” concludes Christine Albert, MD, MPH, chair of the Department of Cardiology in the Smidt Heart Institute.

The study is published in the Journal of the American College of Cardiology.

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