People are losing consciousness while driving far more often than previously thought, often due to undiagnosed but treatable heart rhythm problems, researchers reported Wednesday.
"This problem appears to be reaching epidemic proportions," said Dr. Mark Schoenfeld, an assistant professor of medicine at Yale University School of Medicine and director of cardiac electrophysiology at the Hospital of St. Raphael in New Haven, Conn.
"Over a 14-year period, we studied all people who came to our hospital after an incident of impaired consciousness while driving, and we began to realize how increasingly common the problem is," he said.
In a presentation before a scientific meeting of the North American Society of Pacing and Electrophysiology, Schoenfeld said he and colleagues performed a special heart test on 58 patients who had either lost consciousness on the road, or nearly so, but were able to pull off the road.
Alcohol and drug use was ruled outs, but 81 percent were diagnosed with common heart conditions.
Sixteen had a rhythm disorder in the upper chamber of the heart that causes it to beat faster; 15 had suffered vasovagel syncope, a sudden drop in blood pressure that causes fainting; nine had suffered ventricular tachycardia, an often-dangerous condition in which fast heartbeats arise in the lower chambers of the heart; and seven had problems with electrical impulses in the heart that cause it to beat too slowly.
The remaining 11 patients were found to have problems unrelated to the heart or had suspected but unconfirmed heart problems.
All of the diagnosed patients were treated, either with microsurgery, pacemakers, implantable defibrillators or drugs, and none has since experienced any loss of consciousness while driving.