U.S. researchers said on Monday people who suffer from arrhythmia can avoid needing a defibrillator by learning how to control their emotions.

Arrhythmia, also known as irregular heartbeat can be triggered by anger and other strong emotions in vulnerable people. Studies conducted earlier have linked events such as earthquakes, war or even the loss of a World Cup Soccer match to an increase in rates of death from sudden cardiac arrest, in which the heart stops circulating blood.

Dr. Rachel Lampert associate professor of cardiology and electrophysiology of Yale University in New Haven, Connecticut, who headed the study which appears in the Journal of the American College of Cardiology, said it’s based on a phenomenon called T-wave alternans.

"It's definitely been shown in all different ways that when you put a whole population under a stressor that sudden death will increase," said Dr. Lampert. "Our study starts to look at how does this really affect the electrical system of the heart," Lampert said.

Lampert and colleagues studied 62 patients with heart disease and implanted heart defibrillators or ICDs that can detect dangerous heart rhythms or arrhythmias and deliver an electrical shock to restore a normal heart beat.

In the study these patients had to recount a recent episode which had made them angry while Lampert’s team conducted a test called T-Wave Alternans which measures electrical instability in the heart. The T-wave is the last bump in the electrocardiogram (ECG), which records the electrical activity of the heart as it beats while the T-wave alternans is a wide variation in the height or regularity of that bump.

"We found in the lab setting that yes, anger did increase this electrical instability in these patients," Lampert said. The researchers then followed these patients for three years and kept a record of which patients later suffered cardiac arrest and needed a shock from their implantable defibrillator.

"The people who had the highest anger-induced electrical instability were 10 times more likely than everyone else to have an arrhythmia in follow-up," she said. There were 16 % of the study participants who experienced arrhythmias that set off their implanted defibrillators, and they were found to have higher T-wave alternans than those who did not have arrhythmias.

"One implication of our study is that the changes in the ECG you see with anger are what you see in a stress test," Lampert said. "Is the anger test as good as a stress test? This suggests that it is."

Lampert added that the study findings suggest that anger can lead to sudden death. “It says yes, anger really does impact the heart's electrical system in very specific ways that can lead to sudden death," she said.

The study also indicates that anger can cause electrical instability of the heart, "it suggests that interventions aimed at controlling anger could be a way to decrease exposure to arrhythmias," Lampert said.

A study is now being done at Yale and "We take people who have defibrillators, measure their T-wave alternans and enroll them in a self-control program," she said. "We want to see if we can perhaps improve their quality of life."

"We are thinking about how we manage stress in our lifetimes," Lampert said. "We are thinking about psychological stress management. There are lots of ways people can manage stress in their lives."

Lampert cautioned against extrapolating the results to people with normal hearts. "How anger and stress may impact people whose hearts are normal is likely very different from how it may impact the heart which has structural abnormalities," she said. (Harkiran contributed to this report)