Atrial Fibrillation, Cardiac Death Linked

Atrial fibrillation associated with sudden cardiac death

(RxWiki News) A little flutter in your heart now and then is nothing to see a doctor about, right? Not necessarily. An irregular heartbeat might be a sign of other heart-related risk factors.

Irregular heartbeats could be atrial fibrillation. A recent study found that atrial fibrillation is linked to a higher risk of dying from sudden cardiac death or other heart-related deaths.

Patients with atrial fibrillation symptoms should therefore talk to doctors about other cardiac risk factors they may have.

"See a doctor about an irregular heartbeat."

The study, led by Lin Y. Chen, MD, MS, of the Cardiovascular Division in the Department of Medicine at the University of Minnesota Medical School, aimed to find out whether atrial fibrillation was linked to heart attacks in the general population.

Dr. Chen and colleagues looked at the cardiac symptoms and outcomes in individuals enrolled in two different long-term health studies. One group included 15,439 participants between the ages of 45 and 64, and the other included 5,479 aged 65 and older. The first group enrolled in the study between 1987 and 1989 and were tracked until December 2001. The other group involved two cohorts, one starting in the late 80s and one in the early 90s, who were tracked through December 2006.

In the younger group, over the approximately 13-year study period, there were 894 patients diagnosed with atrial fibrillation, 269 patients who died of a sudden cardiac death and 233 patients who died from heart disease but not as a sudden cardiac death.

In comparing the deaths, the researchers found that each year, approximately 2.9 people out of every 1000 died a sudden cardiac death who had atrial fibrillation. Among those without atrial fibrillation, 1.3 people out a 1000 died from sudden cardiac death each year.

Among the older group, there were 1,458 patients with atrial fibrillation, 292 patients dying from sudden cardiac death and 581 patients dying of another heart-disease-related death. In this group, 12 of every 1000 people with atrial fibrillation died of sudden cardiac death each year compared to 3.8 of every 1000 people without atrial fibrillation.

The researchers determined that having atrial fibrillation does appear linked to a higher risk of sudden cardiac death and of other cardiac-related deaths.

This is a very important study, and one that should provoke a lot of discussion in the medical community," said Sarah Samaan, MD, a cardiologist with Legacy Heart Center in the Dallas/Fort Worth area.

"In general, we cardiologists usually think of atrial fibrillation as a medical condition that, when successfully managed with blood thinners and medications, is more of a chronic but treatable problem than a life-threatening condition," she said. "Of course, complications of atrial fibrillation, including strokes and congestive heart failure, are well known, but fairly infrequent when a patient is closely monitored and appropriately treated."

She said that atrial fibrillation affects the top chambers of the heart (the atria), but doctors have "never had convincing evidence that atrial fibrillation could lead to ventricular fibrillation, a life-threatening heart arrhythmia that if untreated can cause death within minutes."

Yet this study did find a link between atrial fibrillation and both sudden cardiac and other cardiac deaths.

"While the number of patients affected is relatively small, the relative risk is substantial compared to the general population," Dr. Samaan said.

She said the study wasn't designed to determine why this link exists. "But the investigators speculate that the abnormal rhythm transmitted to the ventricles may set up electrical conditions that make the heart more vulnerable to more dangerous heart rhythm disturbances," Dr. Samaan said.

The article was published November 26 in the Archives of Internal Medicine. The research was funded by the National Institutes of Health, the National Heart, Lung and Blood Institute, the National Institute of Neurological Disorders and Stroke, the National Institute on Aging and the American Heart Association. The authors declared no conflicts of interest.

Review Date: 
November 27, 2012