The phrase "I could die of happiness" is not meant to be taken literally.
But as it turns out, you actually can – though it is exceedingly rare.
A new case study, published in Oxford Medical Case Reports, tells the unusual story of a 65-year-old woman who was so desperately happy after attending her daughter's wedding, doctors thought she was having a heart attack.
For three days after the festivities, she suffered chest pain and shortness of breath.
At first, when the woman sought medical advice for her chest pain, which she had experienced a few months prior as well, she was "urgently referred to the emergency department," the case study authors report.
But her tests came back with confusing results.
There appeared to be reduced blood flow to her heart, and this is typically caused by a blood clot.
But no such clot could be found.
Instead, her left ventricle showed a strange ballooning, which was weakening the heart and impairing its ability to pump blood efficiently throughout her body.
Strange as it might sound, that is a sign of sudden and overwhelming joy.
If too much happiness or positive excitement occurs all at once, it can place undue stress on the heart, thereby changing its very shape.
The name for this bizarre syndrome is called takotsubo cardiomyopathy (TTS), a rare and overlooked condition that closely mimics an acute myocardial infarction, or heart attack.
While it is reversible, it is not benign, and can be life-threatening.
TTS is triggered by intense emotional experiences, either good, such as a wedding, or bad, such as a breakup.
The negative version is known as "broken heart syndrome", but the other side of the coin is called "happy heart syndrome", triggered by a flood of positive emotions.
Broken heart syndrome is more commonly known about and studied, though it too is a bit of a medical mystery. It is reversible but not benign.
Research suggests that approximately 1–3 percent of patients who are suspected of having a heart attack, but don't have signs of a clot in their left ventricle, may actually be suffering from TTS.
That's a very small percentage, and it gets smaller yet for happy heart syndrome. Only around 4 percent of reported TTS cases are triggered by positive emotions.
With so few cases on record, however, it's hard to say whether that is reflective of reality or clinical oversight.
TTS was only documented for the first time in 1983 at Hiroshima City Hospital in Japan. It is named after Japanese octopus traps (takotsubo), because patients with the condition have an abnormally shaped left ventricle that resembles these ceramic pots.
The exact mechanisms underlying TTS are not fully understood, but it seems that the outcomes on the heart slightly vary depending on whether it's a case of happy heart syndrome or broken heart syndrome.
"Both conditions involve sympathetic nervous system activation and a catecholamine surge," explain the authors of the case study, "but the neurohormonal responses may differ depending on emotional valence."
Happy heart syndrome is typically associated with mid-ventricular or basal ballooning, whereas broken heart syndrome has a different pattern.
"[Happy heart syndrome] may also present with less severe symptoms and better short-term outcomes, though further data are needed," add the case study authors.
Because the symptoms are less severe, they are sometimes overlooked, even though the outcomes can be life-threatening.
Clinicians, it seems, may be overlooking how stressful joy and happiness can be when experienced in excess.
"Maintaining a high index of suspicion, even in patients without conventional cardiovascular risk factors, is crucial," write the authors of the case study.
At the close of 2025, cardiologist John Madias of the Icahn School of Medicine at Mount Sinai in New York warned that physicians, patients, and the public need to be more aware of happy heart and broken heart syndrome.
Related: Men Are Dying From 'Broken Heart Syndrome' at Twice The Rate of Women
"Short-term and long-term complications and mortality of both these two TTS subtypes are similar, although a higher percentage of men have been reported to have suffered 'happy heart syndrome, in comparison with their rates of 'broken heart syndrome'," says Madias.
"Physicians caring for patients with TTS, as well as investigators researching the pathophysiology of TTS, should further delve into the nature of the positive/pleasant emotions, triggering the 'happy heart syndrome'."
In this particular case study, the 65-year-old woman thankfully achieved complete cardiac recovery and continues to live healthily.
She is, the authors note, "looking forward to witnessing the happiest milestones of her other children in the years ahead."
The study is published in Oxford Medical Case Reports.
This article was fact-checked by Clare Watson and edited by Rebecca Dyer. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.