The higher likelihood of developing cardiomegaly during follow-up in patients with syndrome X and abnormal thallium-201 myocardial perfusion SPECT.

'Syndrome X' describes patients with exertional chest pain and a normal coronary arteriogram. In some patients, acute myocardial ischemia can be demonstrated by regional myocardial perfusion defects on thallium-201 exercise test. However, some patients with typical angina have normal perfusion on thallium-201 heart scintigraphy. It is not clear whether there are different prognoses for patients with normal and abnormal thallium studies. In this study, the clinical features, long term follow-up and clinical results of syndrome X patients with normal and abnormal thallium studies were evaluated to determine the differences between these two groups. Fifty-nine patients (52 males, seven females, mean age 62+/-6 years) with syndrome X were enrolled and divided into two groups on the basis of results of thallium-201 heart scintigraphy. Group I was comprised of 22 patients with normal thallium-201 perfusion scan and group II was comprised of 37 patients with abnormal thallium-201 heart scan. All subjects received coronary arteriography, exercise test, thallium-201 myocardial SPECT, ejection fraction of left ventricle, echocardiography, blood analysis and long term follow-up with questionnaire for 10 years. Lower maximal rate-pressure product and higher angina scores were found in group II. More patients developed cardiomegaly (nine of 33 patients) in group II than in group I (one of 21 patients). Both groups, however, were at low risk for cardiac events (cardiac death or myocardial infarction).