Bouts of anger can create electrical changes in the heart that may be dangerous to some heart disease patients. Implantable cardioverter defibrillators (ICDs) are heart devices implanted in people at high risk of cardiac arrest from ventricular fibrillation, an arrhythmia in which the heart begins to quiver chaotically and stops pumping blood to the body. It is quickly fatal unless an electrical shock is delivered to the heart; ICDs automatically do this. Past studies have found links between strong emotions and the risk of sudden death from cardiac arrest. Similarly, there is evidence that emotional stress can trigger ventricular fibrillation in people with an ICD. Researchers from America studied 62 patients with implantable ICDs. They monitored the patients' heart activity as they underwent mental-stress tests in which they had to recall a recent incident that had angered them. They then followed the patients for 3 years, on average, to chart any instances of arrhythmia requiring an electrical shock from the ICD. It was found that anger-induced changes in the heart's electrical activity predicted patients' risk of suffering a serious heart-rhythm disturbance over the next 3 years. Overall, patients with greater anger-induced electrical changes in the initial heart tests were at greater risk of suffering an arrhythmia. Among those with the highest levels of anger-triggered electrical changes, 40 percent required an ICD shock during the study period, compared with just 9 percent of patients whose heart activity had been less responsive during the stress tests. The most important finding of this study is the mechanism by which anger and strong emotions may be linked to sudden death and it highlights the role of anger in causing electrical changes in the heart. The findings also raise the possibility that testing for anger-induced electrical changes could help predict ICD patients' future heart risks. Such tests could offer an alternative to traditional exercise testing, which many ICD patients are unable to manage.
Journal of the American College of Cardiology
February 2009