Risk of Accidents No Greater for Drivers with Cardiac Arrhythmias

August 09, 2001

Drivers who have suffered a cardiac arrest, some of whom require implantable defibrillators for their condition, have no greater chance of being in a motor vehicle accident resulting from a loss of consciousness than drivers in the general U.S. population, according to an article published in the Aug. 9 issue of the New England Journal of Medicine.

Many patients who experience ventricular tachyarrhythmias, or cardiac arrest, resume driving soon after an episode, and although there exists the potential for another episode to occur while driving, accidents are uncommon - occurring at less than half the rate found in the general U.S. population, reports Toshio Akiyama, M.D., professor of Medicine and director of the Arrhythmia Monitoring and Pacemaker Service at the University of Rochester Medical Center.

"We found that these patients who are at risk for cardiac episodes had no greater risk of being involved in an accident than a healthy driver with no history of cardiac problems," says Akiyama, principal investigator for the study that considered risk incurred by patients who have suffered a cardiac arrest. "

This data may assist physicians in determining which patients should be allowed to drive and how soon after suffering from an arrhythmia episode," he says. "Of course, each patient is different and it is up to physicians to judge on a case-by-case basis."

There were 627 patient cases considered for the study, which was analyzed by researchers at the University of Rochester; the University of Calgary, Canada; the University of Washington, Seattle; St. Luke's/Roosevelt Hospital Center, New York; and MCP Hahnemann University, Philadelphia.

Data was collected via an anonymous questionnaire about driving habits and experiences in this National Institutes of Health-sponsored multicenter clinical study called AVID (Antiarrhythmics Versus Implantable Defibrillators trial). While driving, 2 percent admitted to suffering a syncopal episode (losing consciousness), 11 percent had dizziness that required them to stop the vehicle, 22 percent had dizziness that did not require them to stop the vehicle and 8 percent of the 295 patients driving with implantable defibrillators received a shock as a result of an abnormal heart rhythm.

Fifty patients out of 627 reported having 55 accidents, but only 11 percent of those accidents were preceded by potential arrhythmia symptoms.

The data shows accidents were uncommon and occurred less frequently than that of the annual accident rate of the general U.S. driving population - 3.4 percent versus 7.1 percent. These findings may have an impact on the future development of driving regulations throughout the nation, Akiyama says.

In 1991, only eight of the 50 states had specific guidelines for granting driving privileges to high-risk cardiac patients and none had guidelines for patients with implantable defibrillators. This may be attributable to the lack of data available about the risk for drivers who may suffer cardiac arrhythmias. This study may be used to develop more clear driving regulations for patients who suffer from cardiac episodes, Akiyama says, but it will be up to physicians to determine whether additional factors preclude their patients from driving.

The only driving guidelines available for physicians were released in 1996 in a joint statement from the American Heart Association and the North American Society of Pacing and Electrophysiology. The organizations cautioned that patients with sustained ventricular tachyarrhythmias or ventricular fibrillation being treated with antiarrhythmic drugs should not drive for the first six months after initiation of therapy to document an arrhythmia-free interval before being allowed to resume driving.

"Our study found that 57 percent of patients resumed driving within three months and 78 percent within six months," Akiyama says. "Still, the data shows that this group had no greater risk of accidents."

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