Over five years, government-mandated tracking in France showed that doctors there treated 1,979 patients for serious health problems linked to the use of marijuana, and that nearly 2 percent were with patients suffering from cardiovascular problems including heart attack, cardiac arrhythmia, and stroke, and circulation problems in the arms and legs. In about a quarter of cases, the patient died.

In the U.S., when young,otherwise healthy patients show up in ERs with symptoms of heart attack, stroke, cardiomyopathy, or cardiac arrhythmia, doctors have often noted that the patients are regular marijuana users.

Such reporting is not enough to declare outright that marijuana is a cause of heart disease. But this month, cardiologists writing in the Journal of the American Heart Association warned that "clinical evidence . . . suggests the potential for serious cardiovascular risks associated with marijuana use." And in light of the growing movement to decriminalize marijuana use, they called for data-collection efforts to detect and measure marijuana's heart effects. - L.A. Times