Unusual fatigue, sleep disturbance, and shortness of breath are common symptoms in women who later have a heart attack, says a study published in Circulation, a journal of the American Heart Association, yet less than a third report chest discomfort before the attack.
The study surveyed 515 women aged 29 to 97, with an average age of 66, who had been discharged four to six months earlier from five hospitals in Arkansas, North Carolina, and Ohio, after having had a heart attack.
The women were surveyed for prodromal and acute symptoms. The researchers defined prodromal symptoms as being new or changing in intensity or frequency before the heart attack, being intermittent before the heart attack, and disappearing or returning to previous levels after the heart attack. Acute symptoms were defined as those appearing with the heart attack and not resolving until the women received treatment.
In the survey, the women were shown a list of 70 symptoms they may have experienced during the months leading up to the heart attack and were asked to rate them based on frequency and severity.
Ninety five per cent of women reported having new or different symptoms more than one month before their heart attacks and that these resolved after their heart attacks. This led the researchers to believe that these symptoms were related to the subsequent heart attack.
The most common prodromal symptoms were unusual fatigue (experienced by 70% of the women), sleep disturbance (48%), shortness of breath (42%), indigestion (39%), and anxiety (35%). Only 30% of the women reported chest discomfort before their heart attack.
Dr Jean McSweeney, lead author of the study and a professor at the University of Arkansas for Medical Sciences in Little Rock, said, "The appearance of these symptoms, in conjunction with women's standard cardiovascular risk factors, may assist providers in determining at-risk women who should undergo cardiovascular tests."
She said: "Lack of significant chest pain may be a major reason why women have many more unrecognised heart attacks than men or are mistakenly diagnosed and discharged from emergency departments. Many clinicians still consider chest pain as the primary symptom of a heart attack."
The study did not include a control group of women who did not have a heart attack, so it is not known how many such women might have similar symptoms.
Dr McSweeney acknowledged that this was a "weakness in this study design and it is listed as a weakness in our article." She went: "The reason we did not have a control group is that we did not know what symptoms to look for that were associated with heart attack in women, so we could not look at those symptoms in a control group. Since we now know what symptoms to assess, we plan to have a control group in our next study and to investigate if these symptoms actually predict which women will experience a cardiovascular event."
Dr Nieca Goldberg, chief of cardiac rehabilitation at Lenox Hill Hospital in New York, said that the study could change the way doctors practise.
"If doctors are aware of the early warning signs, they will be more likely to accurately diagnose and take care of the problem before a heart attack, and it could lead to better health care for women," Dr Goldberg said. She added that women often were not accurately diagnosed because they may not have the classic symptoms seen in men.