Caffeine--watch out for "energy drinks".
D001145:Arrhythmias, Cardiac / Q000139:chemically induced* / Q000175:diagnosis; D001628:Beverages / Q000009:adverse effects*; D002110:Caffeine / Q000009:adverse effects*; D002637:Chest Pain / Q000139:chemically induced* / Q000175:diagnosis; D002149:Energy Intake; D006339:Heart Rate / Q000187:drug effects; D006801:Humans
D002110:Caffeine