The arrhythmogenic effects of caffeine in human beings.

IT has been estimated that in a typical year Americans consume nearly 109 kg of coffee.1 In addition, large amounts of tea, cola, and other caffeinated substances are ingested. Caffeine has long been implicated in the causation of arrhythmias, but studies in human beings have been limited. This study was undertaken to determine the cardiac electrophysiologic effects of caffeine, as well as caffeine's arrhythmogenic potential, in normal volunteers and patients with heart disease. Methods Seven normal volunteers with a mean age of 24 years (range, 20 to 31) and 12 patients with a mean age of 43 years (range, 17 . . .