Anger, exertion can spark irregular beat in patients with implantable defibrillators
DALLAS, Sept. 10 – People with implantable defibrillators are more likely to experience a life-threatening irregular heart rhythm when they exercise or get angry, according to research published in today’s rapid access issue of Circulation: Journal of the American Heart Association.
Implantable cardioverter-defibrillators (ICDs) are placed in the hearts of people who have had abnormal heart rhythms (arrhythmias), such as rapid heartbeats or quivering of the left ventricle (ventricular fibrillation), which are potentially life-threatening. The devices identify arrhythmias and give an electrical shock to restore normal rhythm. The shock has been likened to a kick in the chest. People who have ventricular fibrillation and don’t receive a shock are at risk for sudden death.
“We were interested in finding what triggers these dangerous rhythms,” says the study’s senior author Diwakar Jain, M.D., professor of cardiovascular medicine and director of nuclear cardiology at the Drexel University College of Medicine in Philadelphia. “We were able to take recordings from the defibrillators, identify when arrhythmias occurred, and correlate that information with reports of mood and physical exertion.”
Observational studies have suggested that psychological stress increases the risk of sudden death in the population at large. Until now, only indirect or anecdotal evidence suggested that anger and vigorous exercise played a role in arrhythmias, according to Jain.
Between 1996 and 1999, 240 patients completed diaries that reflected their mood and physical exertion levels, each on a five-point intensity scale. After receiving an ICD shock, patients recorded the emotions they were feeling shortly before the shock. They served as their own controls by recording their emotions at the same time a week later (the control period).
Forty-two patients (33 men, average age 65) had 107 confirmed ventricular arrhythmias requiring shock. Anger level was rated three or higher in 15 percent of shock events versus 3 percent during control periods. The 15 percent who were shocked at these times were driving, arguing, gambling or had received bad news.
Patients were engaged in physical activity (level 4 or greater) within 15 minutes preceding 53 percent of shocks and during 32 percent of control periods. The exertion included walking slowly or vigorously, recreational activity or physical activity at work.
The study suggests that anger management techniques and ways to block responses to physical stressors may help avoid arrhythmia incidents, says Jain.