Since at least 1990, scientists have known humans can die of a "broken heart." And while most of the stress that brings on this rare condition, known as takotsubo syndrome (TTS) or stress-induced cardiomyopathy, are heartbreaking—the death of a loved one, divorce, even natural disasters—researchers at University Hospital Zurich in Switzerland now say a small percentage of TTS sufferers came down with the condition after a happy event, a press release notes. This "happy heart" study, published in the European Heart Journal, examined data collected from 1,750 TTS patients who had signed up with the International Takotsubo Registry, a database of both men and women from the US and eight European countries, per Live Science. The researchers found 485 of those with TTS—which temporarily weakens heart muscles and makes the left ventricle balloon at the bottom while the neck stays narrow, causing symptoms similar to a heart attack, including chest pain—had experienced a "definite emotional trigger."
Of those triggers, 96% were linked to sad or stressful events, but 4% were tied to joyous events such as a surprise party or a favorite sports team winning a game. A stunning 95% of both "broken heart" and "happy heart" patients were women. There was a slight difference in how the TTS played out, too: More "happy heart" patients (35%) had hearts that ballooned out in the mid-ventricle than their brokenhearted counterparts (16%), though researchers have to study this more to see what it means. "We believe that TTS is a classic example of an intertwined feedback mechanism, involving the psychological and/or physical stimuli, the brain, and the cardiovascular system," co-author Dr. Christian Templin says. "Perhaps both happy and sad life events, while inherently distinct, share final common pathways in the central nervous system output, which ultimately lead to [TTS]." (Yoga may help TTS patients.)