Researchers uncovered a telltale pattern in the EKGs of certain heart patients. Participants with pacemakers were asked to think of a time when they felt angry. The strong emotions in some apparently triggered disturbances in the heart's electrical waves. In other words, the emotional stress was producing a red flag like physical stress can.
Doctors theorize the rush of adrenaline may cause the electrical disruption. Researchers are now trying to find out if stress reducers like yoga or exercise helps reduce that adrenaline response.