Jan. 17, 2000 (Minneapolis) -- In one of the first studies to show a link between mental stress and death, researchers at Yale University School of Medicine have found that stress may actually lead to sudden death. The findings are particularly important in people with a history of certain irregular heart rhythms that may already predispose them to sudden death.
Scientists have known for some time that sudden death, usually caused by heart attacks associated with a lethal heart rhythm, are more prevalent in populations that suffer earthquake or war. And studies in the laboratory have shown that the primitive fight-or-flight response to stress alters heart rhythms in animals, while anger, anxiety, and performance stress alter heart rates in humans. Now researchers are beginning to learn why.
The patients in the study had a history of a potentially fatal heart rhythm, and all had been implanted with a cardiac defibrillator. An implantable cardiac defibrillator is about the size of a pack of cards and is implanted in the chest. The device is programmed to shock the heart if it detects an abnormal rhythm.
Researchers performed mental stress tests in the patients. These patients were grilled with rapid-fire arithmetic questions and harshly reprimanded for incorrect responses. Patients were then asked to discuss an annoying event, as the interviewer pressed for further details and asked irritating questions.
The study shows that mental stress not only makes abnormal heart rhythm more difficult to control, but the same condition is quicker and more difficult to terminate when patients with irregular heart rhythms are under no sedation. "In patients with a [rapid heartbeat greater than 100 beats per minute], mental arousal [can upset the] circuit, creating a potentially more dangerous [heart rate]," the authors write.
"Patients should be aware that stress really can alter arrhythmias or make heart rhythms dangerous," Lampert tells WebMD. Through their research, Lampert says, researchers will be better able to design preventive strategies in the future.
"This study suggests that treatment of [irregular heart rhythms] should include integrated medical care, which include not only conventional drug and device therapy, but also a complementary medicine component focusing on emotional status and living and working environments," Ruey J. Sung, MD, tells WebMD. "A mutual understanding of the concept of integrated medical care between the physician and patient is key to better control [of irregular heart rhythms]." Sung is director of cardiac electrophysiology and arrhythmia service at University of California-San Francisco Stanford Health Care in Stanford, Calif.
Only one woman was enrolled in the study. Whether the effects of mental stress on arrhythmia differ in women requires further evaluation.
- A new study shows that mental stress changes the heart rate and the rhythm of the heart, even in patients without evidence of heart disease.
- Researchers suggest that mental stress, particularly in patients who already have arrhythmias, can lead to sudden death.
- Treatment of cardiac arrhythmias should include integrated medical care, including a focus on emotional well-being, in addition to treatment with drugs and devices.