June 27, 2000

BIRMINGHAM, AL — One-third of more than 400,000 patients diagnosed with heart attacks between June 1994 and March 1998 did not experience chest pain and were twice as likely to die while in the hospital, according to results of a landmark study by researchers at UAB (University of Alabama at Birmingham). Results of the study were published in the June 28 issue of the Journal of American Medical Association.

Chest pain has long been considered the hallmark symptom of a heart attack. The report is the largest of its kind to compare the symptoms, treatments and outcomes of myocardial infarction (heart attack) patients with and without chest pain in the United States, said lead author John Canto, M.D., a UAB cardiologist and director of UAB's Chest Pain Center.

In the study, Canto calls for new education initiatives nationwide. "Our initiatives need to emphasize that the presence of chest pain is not necessarily the 'golden rule' of heart attacks. And we need to educate both the public and medical providers on the other features and symptoms of heart attacks to facilitate more accurate and expedient diagnoses for these patients who aren't suffering from chest pain."

The sweeping study also found six important factors associated with an absence of chest pain. In descending order of importance, they include prior heart failure, prior stroke, older age, diabetes, women and minorities. The probability of the absence of chest pain increases by almost 50 percent or more in patients with two or more of these risk factors, Canto said.

MI patients without chest pain were significantly more likely to delay going to the hospital, averaging delays of two and one-half hours longer than those with chest pain. Upon arrival at the hospital, they were less likely to be diagnosed with a heart attack at the time of admission and were less likely to receive life-saving therapies.

"Some of these results were quite surprising," Canto said. "They point to the magnitude of the problem, which is under-recognition of the signs and symptoms of myocardial infarction by both patients and possibly physicians.

"Identifying the signs and symptoms of acute MI is paramount to successful management and early treatment of this condition," he added. "Patients must first believe that their symptoms are consistent with a heart attack, and already numerous reports have shown that patients may procrastinate if they do not know their symptoms may indicate a heart attack."

Canto and colleagues examined hospital records from the National Myocardial Infarction Registry 2, which includes hospital data on patients admitted with confirmed myocardial infarction at more than 1,674 participating hospitals.

The one-third of the 434,877 patients diagnosed without chest pain were on average seven years older (74.2 versus 66.9), consisted of a higher proportion of women (49 percent vs. 38 percent) and patients with diabetes (32.6 percent versus 25.4 percent) or prior heart failure (26.4 percent versus 12.3 percent). Lastly, the patients without chest pain had a 23 percent in-hospital mortality rate, compared to 9.3 percent for the counterparts with chest pain.

"This study aims to increase awareness of MI patients with atypical symptoms and to improve clinical practice among such patients," Canto said. "Awareness could allow more rapid and accurate identification of these MI patients by raising the index of suspicion in certain patients without chest pain."

Canto has led a series of studies using national databases, several of which have been published in recent issues of Archives of Internal Medicine and the New England Journal of Medicine. He recently received national attention with results also garnered from a national Medicare clinical database that point to racial disparities in heart treatment.

Editor's Note: We are UAB, the University of Alabama at Birmingham. Please do not refer to us as the University of Alabama.