Type A refers to those who are highly competitive in work and play and who work compulsively, while those with Type B personalities are less competitive and deadline-oriented.
Researchers at the University of California at Berkeley found competitive men were no more likely than easygoing men to die within the first day of a heart attack and were more than 50 percent less likely to die from heart disease later on.
"It was unexpected. The prevailing theory is that individuals who have this behavior called Type A behavior are at increased risk for coronary heart disease," said David R. Ragland, an epidemiologist who headed the study. ''One would expect this risk would continue after a person has had an initial coronary event. What we found here is exactly the reverse."
While the findings do not dispute the theory that aggressive men are much more likely to develop heart disease, they suggest it may be counterproductive to try to change Type A men to more relaxed Type B men after they develop the disease, Ragland said.
In the 1960s, a large research project called the Western Collaborative Group Study concluded that men with Type A personalities were twice as likely as their easygoing counterparts, the Type B's, to suffer heart attacks and heart pain called angina.
That study, based on 8 1/2 years of follow-up, was the first major evidence of a link between Type A behavior and heart trouble. It is still the only study of its kind to find such an association.
According to the theory, Type A's are ambitious, irritable, competitive people, always in a hurry. Type B's are more self-secure and patient and don't let small aggravations bother them.
In the latest research, Ragland and Dr. Richard J. Brand, both of the University of California at Berkeley, went back to the Western Collaborative study to see what happened to the same people years later. They looked at 257 men, both Type A's and Type B's, who were identified as having heart disease.
To their surprise, they found that over the next 13 years, the Type A's were only 58 percent as likely as the Type B's to die of heart problems.
Dr. Joel E. Dimsdale of the University of California in San Diego called the new findings startling in an editorial accompanying the study in this week's edition of the New England Journal of Medicine.
However, Dr. Meyer Friedman of Mount Zion Hospital and Medical Center in San Francisco, who helped define the original Type A concept, dismissed the findings as valueless in a telephone interview.
"This study is flawed," he said, because it misclassifies Type A's as Type B's. Friedman said he had changed his definition of Type A personality and now contends that virtually everyone who has a heart attack under age 65 is Type A.
But Dr. Ray Rosenman, associate chief of medicine at Mount Zion and the director of the same study that defined the Type A concept, disagreed. "I think the findings are completely valid," said Rosenman, who also was a consultant on the new study.
Dr. William Kannel of the Framingham (Mass.) Heart Study, meanwhile, said the findings illustrate the complexity of determining the influence of behavior on disease and the need for more study.
Ragland was uncertain why having an intense, impatient personality would help someone survive a heart attack. But he speculated that Type A heart- disease patients may be more aggressive about seeking and complying with medical care. They may also be more likely to make beneficial changes in their behavior, such as quitting smoking or getting more exercise, he said.
Rosenman disputed that explanation because, he said, Type A people tend to
deny their illness. But he said that denial could be beneficial.
"Since they are deniers, they will probably have less anxiety when they've survived their attack and will therefore tend to suppress the release of adrenalin in response to daily life stressors. It is adrenalin that triggers the fatal cardiac arrhythmia that is the cause of death in many patients," he said during a telephone interview.
Brand said he was still unsure whether Type A behavior contributed to heart disease.
"I'm really disappointed that the situation is now up in the air," he said. "I would have liked to have known: Should I stop being Type A or not? I really don't know, at this point. It's an open question."