Stress Can Cause Heart to Misfire, Study Shows
(Washington, Reuters, 3/22/04)

Willem Kop of the Uniformed Services University of the Health Sciences in Bethesda, MD, and team, performed electrocardiograms on 23 patients with implanted cardioverter defibrillators (ICDs) and 17 healthy volunteers in order to monitor heart rate fluctuations, which can precede arrythmias. The investigators induced stress in the participants by having them recall recent situations that had made them angry and by having them subtract multiples of seven from a four-digit sum, while breaking in to tell them to do better. The researchers found that anger and mental stress are more likely than exercise to result in potentially fatal irregular heartbeats among high risk subjects. The scientists speculate that mental stress affects the heart through different nervous system pathways than physical exercise