Moderate consumption of caffeine does not significantly increase the risk of a coronary event nor increase the frequency of cardiac arrhythmias. This conclusion applies to healthy persons, patients with ischemic heart disease, and those with serious ventricular ectopy. Patients with cardiac disease should be allowed to consume four to five cups of caffeinated beverages per day while in the coronary care unit or progressive care unit under the surveillance of nursing staff.
From NIH. Caffeine not a problem.
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