Grant: Operating Grant

Fainting affects about 50% of Canadians, is the cause of 1-2% of emergency room visits, and probably causes $250 million in health care spending each year. Frequent fainting causes a poor quality of life, and problems at work, at home, and while driving. The most common cause is reflex fainting. This occurs in people of all ages, and while many people only faint once or twice there are hundreds of thousand of Canadians who faint many times, and often more than once a year. Reflex fainting is due to abrupt drops in blood pressure and often drops in heart rate, and these reduce blood flow to the brain enough to make people lose consciousness. There is no known medical treatment for frequent fainting. One possible treatment would be to prevent the reflex that causes the drop in blood pressure. A drug called metoprolol might do this, but only in people over age 40. The evidence for this comes from earlier studies but is pretty weak, and in this study we will test whether metoprolol prevents moderate to severe reflex fainting. We will study 248 patients who have fainted recently, have reflex fainting, and are at high risk of fainting again. They will enroll in a randomized clinical trial. Consenting patients will be assigned randomly to receive either metoprolol or a dummy pill called a placebo, and we will follow them for 1 year. We then will compare the number of people who faint in those taking metoprolol compared to placebo. We will also compare the frequency of fainting, quality of life, and health costs, in each arm of the study. This study will have centres in Canada, the United States, Europe and South America. It is the only study of its kind and it will be pivotal.