Heart Problems Prompt Fainting Behind the Wheel

May 17, 2000 (Washington) -- People involved in car accidents that occur under mysterious circumstances may have passed out at the wheel due to a common, but often undiagnosed, heart condition, according to researchers at Yale University.

The researchers are specialists in testing used to diagnose irregular heartbeats and other disorders in which the heart may beat too fast or two slow. They want to warn people who may have "fainting spells" not to ignore them, because they are likely to happen again and can be treated, Mark H. Schoenfeld, MD, tells WebMD. Schoenfeld is the director of the heart testing lab at Hospital of San Raphael and an associate professor at Yale University School of Medicine in New Haven, Conn.

Schoenfeld and his colleagues studied the results of tests performed over the past 14 years on patients who were referred to them after an accident. In all cases, their primary care doctor and a cardiologist had been unable to determine what caused their crash.

"Most of these patients come to us with their doctors throwing up their hands in frustration, and the patients are even more frustrated than the physicians because they are fearful of going back to driving," he says. "All of the patients referred to us say, 'I did not fall asleep.' A lot of times, they will have a passenger in the car, and they will say, 'This patient just slumped over, or they turned white, or they just didn't look right, or they were just dazed, or their eyes rolled back.'" Schoenfeld adds that for many patients, this happened more than once.

"About 80% of the patients who underwent the evaluations that we performed were found to have an otherwise unsuspected [heart] condition that could well explain why they had their events," he says. "And furthermore, treatment of that condition has allowed them to go back to driving, safely."

Testing on the patients' hearts revealed that some of them had rapid heartbeats that were most often caused by an extra electrical circuit in their hearts, a condition that they could have been born with. This causes their heart to speed up, leading to a drop in blood pressure, less blood supply to their brain, and ultimately a fainting spell, Schoenfeld explains.

In some cases, surgery is required, and medication is used for others. In all but one of the patients studied in the lab, patients had no more incidents of fainting while driving, he says.

These episodes seem to be more common among elderly people, but can occur at all ages, Schoenfeld says. There also is no clear pattern of the spells. "I have patients that have had four separate spells in 17 years. I have patients who have one spell a year. I have patients who can go 20 or 30 years without a spell before another spell," he says.

People may hurt or kill themselves or others if these spells occur while they are driving. Some families have been subjected to unnecessary anguish, because they were mistakenly told that the car accident occurred when their loved one attempted suicide. In two cases, the people recovered; they could distinctly remember passing out or having chest pain before they crashed, Schoenfeld says.

All of the patients Schoenfeld treated for these problems, particularly the older ones, were quite happy to be driving again, he adds. "Some of these people are dependent on driving for their livelihood. A lot of the patients are older, and they want to drive just because they have the time and they have the right. I can't tell you how many of my [older] patients have recreational vehicles who are traveling all over the place," he says.

Vital Information:

  • Researchers suggest some car accidents that happen under mysterious circumstances may actually be caused by drivers with undiagnosed heart conditions passing out behind the wheel.
  • The researchers urge people who suspect they have "fainting spells" not to ignore their symptoms, because the conditions can create dangerous situations and often can be treated successfully.
  • In the new study, eight out of 10 participants were found to be suffering from an undiagnosed heart problem. With treatment, all but one patient was able to go back to driving without experiencing fainting again.