In England, clopidogrel is only recommended for heart attack patients when it is used on its own. A second part of the study looked at the effect of giving patients early treatment with the beta- blocker drug metoprolol. The drug cut the relative risk of repeat heart attacks and dangerous heart rhythms by about 15% to 20%. But at the same time it increased the risk of car- diac shock by 30%, espe- cially during the first day or so after admission. Professor Jeremy Pearson, associate med- ical director of the British Heart Foundation, said, "This is the most recent of several studies that have shown that clopido- grel has benefits for patients with vascular disease. "Its use is already well established for patients with unstable angina and this study confirms that it is safe and effective also in heart attacks." But he said the study on metoprolol showed that such drugs should be used with caution in the early hours of an attack. Meanwhile, the Lancet also reported that waist- to-hip ratio is a better obesity measure for assessing the risk of a heart attack than body mass index (BMI). The work by Canadian researchers is the latest in a series of studies to cast doubt on BMI.