The University Hospital Zurich study, in the European Heart Journal, suggests about one in 20 cases is caused by joy.
The condition is normally temporary and people are generally fine afterwards.
In the study of 1,750 patients, researchers discovered heart problems caused by:
- a birthday party
- a son's wedding
- meeting a friend after 50 years
- becoming a grandmother
- a favourite rugby team winning a game
- winning a casino jackpot
- a computerised tomography (CT) scan giving the all-clear from another condition
Dr Jelena Ghadri, one of the researchers, said: "We have shown that the triggers for takotsubo syndrome can be more varied than previously thought.
"A takotsubo syndrome patient is no longer the classic 'broken-hearted' patient, and the disease can be preceded by positive emotions too.
"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 takotsubo syndrome just as much as a similar patient presenting after a negative emotional event."
'More research needed'She said it was likely both sad and happy events shared a common "emotional pathway" leading to the condition.
Prof Peter Weissberg, the medical director of the British Heart Foundation, said: "Takotsubo syndrome is a rare event.
"This study suggests that in a very few cases, the triggering event may be a happy one.
"Much more research is needed to understand how such emotional events can trigger temporary heart damage in a few susceptible individuals."