Every year, eight to 10 million people in the US go to emergency departments for chest pain. But only 15-30 per cent of them are having a heart attack.
Researchers found that patients with chest pain of short duration, less than 5 minutes, are unlikely to have a heart attack and have a good prognosis at 30 days.
Researchers at Henry Ford Hospital in US studied the relationship between the length of time that a patient experienced chest pain and a diagnosis of heart attack in patients evaluated in the emergency department.
"The variety of symptoms any one patient may experience during a heart attack is a challenge to the physician who is trying to distinguish between patients who are having a heart attack and those who are not," said James McCord, a cardiologist at Henry Ford Hospital on the research team.
"Although an electrocardiogram (ECG) and cardiac markers in the blood are important in the evaluation of patients with a possible heart attack, they are not 100 per cent accurate," McCord said.
Records of patients who were evaluated for possible heart attack in the emergency department at Henry Ford Hospital between January and May of 1999 were studied. Only patients for whom chest pain duration and 30-day follow-up data was available were selected.
Of 426 patients included in the study, 38 (less than 9 per cent) had a final diagnosis of heart attack, with average chest pain duration of 120 minutes, compared with 40 minutes in patients without heart attack.
In patients with chest pain lasting less than five minutes, there were no heart attacks and no deaths at 30 days.
"These findings suggest that patients with chest pain lasting less than five minutes may be evaluated as an out-patient in their doctor's office; while patients with chest pain greater than 5 minutes, without a clear cause, should seek prompt medical evaluation in an emergency department," said McCord.
The researchers concluded that patients with heart attack have longer duration of chest pain than those not experiencing a heart attack.
Researchers added that, since this study was done at one hospital with a relatively small number of patients, further study is needed.
The research was published in the journal Critical Pathways in Cardiology.