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.