Add anger to the list of possible contributing factors to heart attacks. U.S. researchers recently discovered that people who are more prone to angry outbursts, and who are angry in general, may be at an increased risk for developing a heart attack.

In combing through medical literature, the researchers discovered that rage often occurs before an attack, and may even be a trigger.

However, they caution that more research needs to be done to determine a possible link and to see if anger-relieving strategies can help to avoid complications.

The study found that people who have severe outbursts of anger are more likely to suffer from a cardiovascular event within two hours after the outburst, in comparison to those who remained calm that entire time.

In an online report in the European Heart Journal, the researchers explained that, “The relative risks estimated in this meta-analysis indicate that there is a higher risk of cardiovascular events after outbursts of anger among individuals at risk of a cardiovascular event, but because each episode may be infrequent and the effect period is transient, the net absolute impact on disease burden is extremely low.” They continued, “However, with increasing frequency of anger episodes, these transient effects may accumulate, leading to a larger clinical impact.”

Dr. Murray A. Mittleman, lead author and associate professor of medicine at Harvard Medical School, said, “The relative risk was similar for people who had known pre-existing heart disease and those who didn’t.”

For the study, each patient was compared to his or her unique baseline risk. Mittleman explained, “A person with pre-existing heart disease or cardiovascular disease, the absolute risk they are incurring is much greater than (that of) a person without cardiovascular disease or risk factors.”

“If we look at somebody at higher risk for having cardiovascular events, and they get angry multiple times a day, this can lead to 650 extra heart attacks per year out of 10,000 a year,” says Mittleman. For a person who is at relatively low risk of suffering a cardiovascular event, but who experiences frequent episodes of anger, he says, “we estimate there would be about 150 extra heart attacks out of 10,000 a year.”