Women, especially younger women, are more likely than men to show up at the hospital with no chest pain or discomfort after having a heart attack - and they are also more likely to die than men of the same age, according to a US study.
That lack of symptoms can result in delayed medical care and differences in treatment, said researchers, whose findings appeared in the Journal of the American Medical Association.
"They might not even know they're having a heart attack," said John Canto, from the Watson Clinic in Lakeland, Florida, who worked on the report.
He noted that while the results are based on a study of more than a million heart attack patients, they are still preliminary. But, he added, they do challenge the notion that chest pain and discomfort should be considered "the hallmark symptom" for all heart attack patients.