More than four out of 10 people experiencing a heart attack do not realise they are having one, according to research published today. A total of 43% of heart attacks are not diagnosed as such at the time, the study of more than 4,000 people aged 55 and over found.
And women are far less likely to realise they are having a heart attack than men - with over half (54%) of attacks in women going undiagnosed compared with a third (33%) in men.
The findings, published in the European Heart Journal, Europe's leading cardiology publication, are based on an analysis of 4,187 people living in a suburb of Rotterdam but are thought to be equally applicable to people in Britain.
Researchers, from the Erasmus Medical Centre, took ECGs - electrocardiograms, charts which record the electrical impulses in the heart - of the volunteers at the start of their research and then repeated this at least once during six years.
Looking for evidence of heart attacks, they found that there were nine for every 1,000 participants. Men had a higher incidence - 12 per 1,000 of which 8.4 were recognised and 4.2 unrecognised - while there were seven per 1,000 for women.
But women were less likely to recognise heart attacks - with less than half (46%) realising what had happened.
Eric Boersma, associate professor of clinical cardiovascular epidemiology, and the report's co-author, said researchers were surprised by the high percentage of undiagnosed heart attacks and suggested they may have gone unrecognised because of atypical symptoms.
"We suspect that with those that went unrecognised, people didn't experience severe chest pains or pain in the left arm but more a feeling of being generally sick.
"You can have a heart attack on several spots of your heart and, if it's on the lower side, you could experience that as stomach pain and misinterpret it," he said.
Women and diabetics experience chest pain differently to men, Dr Boersma added, while women think they are more likely to suffer from breast or gynaecological cancer than heart disease.
The findings - based on research conducted between 1990 and 1999 - come a week after research from Trinity College Dublin discovered that women suffering heart attacks turn up to hospital far later then men, after an average 14 hours compared with 2.8 hours, because they do not see themselves as heart attack victims.
