Usefulness of intravenous dipyridamole combined with pacing stress for detection of myocardial ischemia in coronary artery disease.

Abstract

In order to establish a more clinically useful diagnostic method to detect myocardial ischemia, a stress test of 0.56 mg/kg of intravenous dipyridamole (D), an atrial pacing (P) and the combination of both (D + P) were administered to 14 patients with significant coronary stenosis and 8 patients with normal coronary arteriogram. The effects on regional coronary hemodynamics and myocardial metabolism were subsequently studied. Treadmill exercise tests in 15 patients and thallium-201 exercise myocardial scintigraphy in 14 patients were also performed at another time. When the uptake ratio of myocardial lactate less than 0% was used as an indicator of myocardial ischemia, 100% (12/12) of sensitivity and 100% (6/6) of specificity were obtained with (D + P)-test in diagnosis of significant coronary stenosis and its sensitivity was significantly higher than that with P-test (43%) or with D-test (31%). Even though sensitivity and specificity of exercise electrocardiogram (70% and 50%) or thallium-201 exercise myocardial scintigram (88% and 80%) in diagnosis of coronary stenosis were not significantly lower than those of (D + P)-test respectively, myocardial ischemia could also be detected with (D + P)-test in two patients at the region perfused by the infarct-related artery, which had not been detected by thallium-201 exercise myocardial imaging. We conclude, (D + P)-test combined with investigation of myocardial lactate metabolism is quite useful to detect myocardial ischemia.