Posted on March 20, 2001 at 8:42 a.m.

BIRMINGHAM, AL — Nearly one-half of more than 3,000 elderly Medicare patients diagnosed with unstable angina did not suffer from chest pain or other typical symptoms usually associated with angina, according to a study by UAB researchers.

The study, led by UAB cardiologist John Canto, M.D., is a follow-up to his landmark study published in the June 2000 issue of the Journal of the American Medical Association which found that one-third of more than 700,000 heart attack patients did not suffer from the hallmark symptoms of heart attack. The new study will be presented at next week's American College of Cardiology meeting in Orlando, Florida.

Unstable angina occurs when blood flow in the heart becomes restricted, but occurs before the blood flow restriction is severe enough to cause cell death — like a heart attack. Unstable angina symptoms typically occur suddenly and sporadically with sudden worsening over days or weeks and with a more severe short-term prognosis than stable angina, which is typically a more chronic condition.

Although angina has been synonymous with chest pain, Canto says the study results clearly show that it is time to redefine the classical definition.

In this study, Canto and colleagues examined the medical records of 3,015 Medicare patients hospitalized at 22 Alabama hospitals with a confirmed diagnosis of unstable angina between 1994 and 1998. Canto said diagnosis was confirmed by examining certain cardiac markers, or enzymes released into the blood when blood flow is restricted. Symptoms were classified as typical or atypical.

Typical symptoms included chest pain located below the sternum, in the left chest or right chest. They also included chest pain described as squeezing, tightness, aching, crushing, discomfort, dullness, fullness, heaviness, pressure or pains relieved with rest or nitroglycerin or worsened with activity.

Atypical symptoms included pain in the jaw, shoulder, arm, neck, face, ear or stomach, shortness of breath, nausea, vomiting, profuse sweating, light-headedness or fainting.

Results showed that important characteristics of those patients who did not suffer typical symptoms included age, gender and those who had not suffered from prior heart attack, but race was not found to be a distinguishing characteristic. Of the 44.5 percent of patients with atypical presentation, 58.3 percent were women. The mean age of those with atypical symptoms was 73, compared with a mean age of 71 among those with typical symptoms. Fifty-eight percent of the patients with typical symptoms had suffered from a prior heart attack.

"This study, like the previous one, calls for national educational initiatives to increase awareness of these atypical presentations to insure recognition and appropriate care," Canto said.

Canto's study will be presented at the 50th annual Scientific Sessions of the American College of Cardiology in Orlando at 10 a.m. EST March 21.