Feeling angry could trigger a heart attack, according to a recent study.

Researchers at the University of Sydney found that the risk of a heart attack is 8.5 times higher in the two hours following a burst of intense anger.

"Our findings confirm what has been suggested in prior studies and anecdotal evidence, even in films -- that episodes of intense anger can act as a trigger for a heart attack," Dr. Thomas Buckley, lead author of the study, said in a statement. "The data shows that the higher risk of a heart attack isn't necessarily just while you're angry -- it lasts for two hours after the outburst."

For the study, researchers investigated the link between acute emotional triggers and high risk of severe cardiac episodes.

In the study, "anger" was qualified as 5 and above on a 1-7 scale, referring to "very angry, body tense, clenching fists or teeth, ready to burst," up to "enraged, out of control, throwing objects." Anger below this level was not associated with increased risk.

"The triggers for these burst of intense anger were associated with arguments with family members (29 percent), argument with others (42 percent), work anger (14 percent) and driving anger (14 percent)," Buckley said.

The study was an investigation of consecutive patients suspected of heart attack and confirmed by angiography reports at Royal North Shore hospital. Patients confirmed with acute coronary blockage were admitted, interviewed about their activities in the 48 hours before the onset of symptoms, and usual frequencies of activities were recorded for comparison.

"Our findings highlight the need to consider strategies to protect individuals most at risk during times of acute anger," Buckley said.

The findings are detailed in the European Heart Journal: Acute Cardiovascular Care.