It’s no secret that emotional stress can send our hearts aflutter. But new research suggests that how the heart copes with anger could predict life-threatening irregular heartbeats in vulnerable patients. Yale cardiologist Rachel Lampert, gave EKGs to 62 patients with preexisting heart disease who had defibrillators implanted in their chests. Upon retelling a memory that made them angry, some experienced a spike. Compared to those whose hearts were unresponsive to anger, the study found that these people were 10 times more likely to have their defibrillators fire a lifesaving shock in the next three years.