TUESDAY, Feb. 14, 2006 (HealthDay News) -- More than four in 10 heart attacks go undiagnosed at the time they occur, a new European study finds.
And these so-called "silent heart attacks" more often go unnoticed in women -- more than half of the attacks in women went unrecognized, compared with one-third in men, the researchers said.
"There is quite a proportion of myocardial infarctions [heart attacks] that is clinically unrecognized by the patient him or herself, but also by the medical system," said study co-author Eric Boersma, an associate professor of clinical cardiovascular epidemiology at Erasmus Medical Centre in Rotterdam, the Netherlands. "We know from other research that unattended myocardial infarctions do have prognostic implications in the sense of lower life expectancy."
The results relating to women were particularly troubling to some experts.
"Clearly heart attacks are being missed in women, and these are women who were in the health-care system," said Dr. Nieca Goldberg, chief of women's cardiac care at Lenox Hill Hospital in New York City, and author of The Women's Healthy Heart Program. "Two-thirds of women with a heart attack never make it to a hospital, and these women did make it and the heart attacks were still missed. Obviously, this is a big disappointment."
The study authors suggested that periodic, repeat electrocardiographic screening (ECG) could turn up evidence of heart attacks that had previously gone unnoticed.
The findings appear in the Feb. 14 issue of the European Heart Journal.
According to the study authors, deaths from ischemic heart disease -- when blood flow and therefore oxygen are restricted due to narrowed heart arteries -- are decreasing. But this type of heart disease will remain a major health issue in the coming decades, largely because of the continued aging of the population.
Heart attacks are the most severe outcome of ischemic heart disease, and can lead to death, the researchers said.
Previous studies have indicated that up to 44 percent of these heart attacks are clinically unrecognized, but the data have been limited and contradictory.
For this study, the researchers analyzed more than 4,000 men and women over the age of 55 who were participating in the Rotterdam Study, a prospective population study being conducted in a suburb of Rotterdam.
Between 1990 and 1993, men and women with no evidence of having had a heart attack were enrolled in the study, underwent a baseline ECG and medical examination and at least one follow-up examination during 1994-95 and/or 1997-2000.
Forty-three percent of the total heart attacks went unrecognized, including one-third in men and more than one-half in women, the researchers found.
The gender discrepancy persisted as age increased from 55 to 80.
Although the study was conducted in the Netherlands, the researchers believe the results could be extrapolated to any developed country.
A number of factors may explain why heart attacks go unnoticed: Atypical symptoms, different symptoms in women than in men, different symptoms in the elderly and people with diabetes are some, to name a few.
But it's important to recognize them because patients who have had one heart attack are at a higher risk for additional cardiovascular complications. As such, they could likely benefit from preventive treatment, including aspirin, beta blockers and statins, as well as lifestyle changes, the researchers said.
Regular ECG screenings could determine who has suffered a silent heart attack and who needs extra care, the authors stated.
"If you want to diagnose these earlier, then you have to one way or another make those repeat ECGs," Boersma said. "But before we can make such a statement, we need to do a formal cost-benefit analysis to see if it's beneficial to do this in a large population above the age of 55."
The American Heart Association has more on ECGs.