Sixteen years after scientists first discovered “broken heart syndrome,” a new study suggests its nickname may be misplaced. Why? Because happy hearts can cause it too.

Characterized by shortness of breath and difficulty breathing, Takotsubo cardiomyopathy (TTS) gets the playful “broken heart” moniker from the belief that the weakening of heart muscles, which causes a ventricle to balloon out, is prompted only by sadness.

But in a new study published Thursday by the European Heart Journal, scientists catalog 20 cases in which TTS was caused by something happy. It’s the first time scientists have found a positive cause for the rare condition. The discovery suggests that both sad and happy events operate through the same neural pathways.

TTS, also referred to as transient apical ballooning syndrome, was discovered by Japanese scientists in 1991. They found the condition while analyzing autopsies from people who died of assaults but weren’t actually injured. Due to the nature of the ballooning ventricle, they named it after a pot used to catch octopuses.

The first case in the U.S. was not documented until 1998, and scientists here didn’t begin researching it seriously until the early 2000s. The first major study in America, performed at Johns Hopkins, was released in the New England Journal of Medicine in 2005 with the headline: “‘Broken Heart’ Syndrome: Real, Potentially Deadly but Recovery Quick.”

Since then, scientists and the general public alike have been enamored by the condition, but until now, wrote about it exclusively as something tied to extreme sadness.

After establishing the Takotsubo registry, an enormous online database cataloging patients with TTS, cardiologist and leader of the study Dr. Jelena Ghadri began noticing positive events in some of the descriptions. To determine how often this occurred, she and her team zeroed in on the first 1,750 patients who registered.

Hailing from nine countries, 95 percent of the patients were female, with an average age of 65. Of all the cases, 485 were triggered by an emotional event. Of that number, 20 of them (4 percent) were positive—a phenomenon the researchers call “happy heart syndrome.” Among the happy events that they observed: a birthday party, wedding, several wins at the casino, and the birth of a grandson.

“We have shown that the triggers for TTS can be more varied than previously thought. A TTS patient is no longer the classic ‘broken hearted’ patient, and the disease can be preceded by positive emotions too,” said Ghadri. “Clinicians should be aware of this and also consider that patients who arrive in the emergency department with signs of heart attacks, such as chest pain and breathlessness, but after a happy event or emotion, could be suffering from TTS just as much as a similar patient presenting after a negative emotional event.”

The researchers point out that despite the “extensive chart review,” the sample size necessitates more research. Still, the overall result is a potentially “substantial paradigm shift” from the commonly accepted views about TTS. “Our findings broaden the clinical spectrum of TTS. They also suggest that happy and sad life events may share similar emotional pathways that can ultimately cause TTS.”