Many Heart Attacks Go Unrecognized
Study Highlights Risk of Hidden Heart Attacks
Feb. 14, 2006 -- People often have heart attacks and don't realize it, according to a new study.
The study appears in the European Heart Journal. Its findings include:
- In people aged 55 and older, 43% of heart attacks happened unrecognized until an incidental EKG was done, which showed evidence that one had occurred.
- Women were more likely than men to have unrecognized heart attacks.
Heart attacks damage the heart, making future heart problems more likely. People with undetected heart attacks could have a false sense of confidence about their heart health, note the researchers.
They included Jacqueline Witteman, PhD, of the epidemiology and biostatistics department at Erasmus University in the Netherlands.
Tracking Heart Health
More than 5,100 people in the Dutch city of Rotterdam participated in the study. They were about 67 years old when the study started in the early 1990s. None had a known history of heart attacks or evidence of unrecognized heart attack on a baseline EKG.
Participants got EKG tests, which check the heart's electrical activity. After a heart attack, an EKG is likely to have abnormal findings revealing past heart attack. This is due to heart muscle injury caused by a heart attack.
EKG tests were done at the study's start and again at follow-up visits during the 1990s. Most participants got at least one follow-up EKG by the late 1990s.
The researchers' goal: See which people had heart attacks and how often those heart attacks went undetected.
Hidden Heart Attacks
Overall, 43% of the group's heart attacks went initially undetected. They were only discovered later during the scheduled EKG follow-ups. Previous studies have estimated that between 4% and 44% of heart attacks go unrecognized, write Witteman and colleagues.
In their study, heart attacks were more likely to go unrecognized in women than in men.
A third of the men's heart attacks went undetected without EKG. So did more than half (54%) of the women's heart attacks.
That gap may stem from different heart attack symptoms or understanding of those symptoms in women, the researchers note.
"It should be noticed in this respect that women and their doctors have traditionally worried about mortality from breast and gynecological malignancies, rather than heart diseases," they write.