陳旧性心筋梗塞症における運動負荷thallium-201心筋シンチグラフィーの臨床的評価
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概要
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The present study was undertaken in order to evaluate the usefulness of thallium-201 stress myocardial scintigraphy (Tl-201 SMS) in identifying patients with multivessel coronary artery disease and assessing residual jeopardized myocardium and estimating the size of old myocardial infarction (OMI). In 48 patients with OMI, stress test with Tl-201 myocardial scintigraphy and electrocardiography using ergometer, left ventriculography and coronary angiography were performed. Of 45 patients with OMI except reinfarction, abnormal Q wave in ECG was absent in 3 patients (7%) and their scintigraphic infarct size (SIS) was smaller than other patients with ECG indicating the evidence of OMI (2.3±4.0% in no abnormal Q wave group ; 33.5±9.7% in inferior MI group ; 39.0±20.8% in combined anterior and inferior MI group). Thirteen out of 19 patients (68%) with multivessel coronary artery disease were corectly diagnosed with exercise electrocardiography but 6 patients with anterior wall infarction fell into the false negative group. Tl-201 SMS had a high degree of sensitivity (18/19 ; 95%) in detecting additional significant coronary artery disease and the positivity of this method was not affected by the site of infarction and involved vessel. SIS was larger in patients with inferior wall and combined anterior and inferior wall infarction than that in anterior wall infarction (39.0±20.8%, 33.5±9.7% vs 17.0±15.3%) and it was also larger in patients with multivessel disease than in those with single vessel disease. SIS correlated closely with percent abnormally contracting segment (r=0.76, p<0.001) and left ventricular ejection fraction (r=-0.55, p<0.001) which showed low value in patients with SIS over 20%. No significant difference in SIS, however, was found between patients with normal (≦12mmHg) and elevated left ventricular end-diastolic pressure (>12mmHg). In addition, SIS did not correlated with exercise capacity. From these results, it is indicated that non-infarcted area as well as infarcted area should be considered in evaluating pathophysiologic aspects of OMI and accordingly it is important to detect transient myocardial ischemia in non-infarcted area during exercise. It is, thus, concluded that Tl-201 SMS is a useful noninvasive tool for asessing the size of myocardial scar and the extent of additional transient myocardial ischemia in non-infarcted area in patients with OMI.
- 神戸大学の論文