The triggers for heart attacks may be quite different from the factors that lead to development of coronary heart disease over the long term, such as cigarette smoking, lack of exercise, work stress, social isolation, anxiety and depression, say Philip Strike and Andrew Steptoe of University College London.

Their findings, based on a review of dozens of studies conducted between 1970 and 2004, are published in the current issue of http://Psychosomatic Medicine.

One in a Million

"Physical exertion has an apparently paradoxic association with triggering" severe chest pain, heart attack or sudden death, the review notes. Physically fit people enjoy a reduced risk of heart attacks, while inactive cardiac patients who suddenly engage in vigorous activity may do so at their peril.

In one study, people who exercised rarely were nearly seven times more likely to suffer a heart attack after strenuous exertion than those who exercised more than three times a week.

Nevertheless, the absolute risk of cardiac events after any single bout of activity remains less than one in a million, the authors point out. This includes sexual activity, where there is also a slightly elevated risk for heart patients, they note.

Because strong social support and marital relationships promote physical well-being, "my view is that it is much more important for people to maintain good personal and sexual relationships than it is to worry about this small increase in risk," Steptoe says.

Questionable Reports

Emotional distress -- along with natural disasters, war and sporting events -- also may trigger heart attacks in vulnerable individuals, according to the review.

"The evidence of triggering by physical exertion and emotional stress is compelling," the authors observe. Furthermore, they note, "it is likely that triggers are more potent when acting in combination or when they are present at particular times of day."

Nevertheless, Strike and Steptoe acknowledge that results often are collected by asking heart-attack patients or their survivors to compare normal activity with what took place immediately before a heart attack occurred.

Such reports are "susceptible to memory loss, social acceptability bias, and to patients' private beliefs about the causes of heart disease," the authors say. Also, some apparent triggers actually may be symptoms, rather than causes, of the earliest stages of a heart attack.

Behavioral Cardiology

The review has important implications for clinicians, says Steptoe. "Physicians and cardiologists need to talk to patients with ACS (acute coronary syndromes) about their experiences in the hours leading up to the cardiac event," he advises.

For example, if a heart attack occurs after vigorous exertion, the patient may be fearful of future exercise. "Patients need to realize that they would still benefit greatly from regular physical activity," Steptoe notes.

Evidence linking various psychosocial factors with coronary artery disease has grown so strong that the Journal of the American College of Cardiology recently featured an article on the emerging field of "behavioral cardiology."

"The real battlefield has become 'What should cardiologists do with this information?' given that there are no guidelines for integrating the management of psychological factors into cardiac practice," says lead author Dr. Alan Rozanski, of St Luke's-Roosevelt Hospital Center and Columbia University in New York.

He and coauthors recommend that, for now, cardiac specialists screen for psychosocial issues, recognize that some of these issues can be managed within cardiac practice, and consider referring patients with severe psychological issues to appropriate specialists.