Detection of residual jeopardized myocardium 3 weeks after myocardial infarction by exercise testing with thallium-201 myocardial scintigraphy.

Abstract

The usefulness of Tl-201 exercise myocardial scintigraphy in identifying patients with multivessel coronary artery disease (MVCAD) and residual jeopardized myocardium after myocardial infarction (MI) was evaluated in 32 patients 3 wk after MI. All patients underwent limited multilead submaximal treadmill testing, Tl-201 myocardial scintigraphy at end-exercise and at rest and coronary and left ventricular angiography. Tl-201 perfusion defects were categorized as reversible (ischemia) or irreversible (scar). The conventional exercise test was designated positive if there was ST depression .gtoreq. 1 mm and/or angina. Jeopardized myocardium (JEP) was defined angiographically as a segment of myocardium with normal or hypokinetic wall motion supplied by a significantly stenotic major coronary artery. MVCAD was defined as 2 or more significantly stenotic coronary arteries. Significant coronary stenosis was categorized as 50-69% diameter narrowing or .gtoreq. 70% diameter narrowing thereby yielding, respectively, 2 subgroups each of jeopardized myocardium (JEP-50 and JEP-70) and MVCAD (MV-50 and MV-70). Clinical findings of angina, heart failure or ventricular arrhythmias during the late convalescent period after MI occurred in 4 of 10 patients (40%) with MV-50, 5 of 16 (31%) with MV-70, 4 of 10 (40%) with JEP-50 and 5 of 18 (28%) with JEP-70, and thus were insensitive for detecting MVCAD and JEP. Reversible ischemia and/or a positive conventional exercise test occurred in 5 of 10 patients (50%) with MV-50, 13 of 16 (81%) with MV-70, 4 of 10 (40%) with JEP-50 and 15 of 18 (83%) with with JEP-70. All 8 patients with Tl-201 reversible ischemia and a positive conventional exercise test had JEP-70. In 30 of 31 patients (97%) with angiographic asynergy Tl-201 scar was detected. No complications were associated with exercise testing. Thus 3 wk after MI, Tl-201 exercise myocardial scintigraphy is a safe, useful, noninvasive tool for identifying patients with MVCAD and residual JEP and is more reliable than clinical findings during convalescence after MI.