736 Automated classification of wall motion abnormalities by analysis of left ventricular endocardial contour motion patterns

Abstract

Background: Previous studies have shown that transmural myocardial ischemia caused by sudden epicardial coronary artery occlusion determines a typical sequence of events characterized, in order, by left ventricular wall motion abnormalities, ST segment modifications and, only at the end, angina. In this study, we investigate if this typical ischemic cascade presents with the same modalities also during subendocardial ischemia induced by dipyridamole infusion. Patients and Methods: A total of 41 patients (63±9 years; 12 women) with chronic stable angina and angiographically documented coronary artery disease (1-vessel: 14 [34%]; 2-vessel: 8 [19%]; 3-vessel: 19 [46%]) underwent dipyridamole stress echocardiography (total dose: 0,84 mg/kg iv). Cardiac images were acquired by a 2.5 MHZ probe connected to a Toshiba set, Power Vision 8000. Results: During test, 39 patients (95%) had left ventricular wall motion abnormalities, 31 patients (75%) had ST segment depression and 32 patients (78%) had angina. The first manifestation of ischemia was left ventricular wall motion abnormalities in 7 patients (17%), ST segment depression in 16 patients (39%) and angina in 9 patients (22%). When considering only the 21 patients who developed all three manifestations of ischemia during dipyridamole stress echocardiography, left ventricular wall motion abnormalities were the first manifestation of ischemia (alone or in association with ST segment depression or angina) in 5 patients (24%), ST segment depression was the first manifestation of ischemia (alone or in association with left ventricular wall motion abnormalities or angina) in 14 patients (66%) and angina was the first manifestation of ischemia (alone or in association with left ventricular wall motion abnormalities or ST segment depression) in 8 patients (38%). Conclusion: Our data indicate that dipyridamole induced subendocardial ischemia results in a very variable sequence of events, which doesn’t seem to reproduce the typical ischemic cascade described after sudden coronary artery occlusion. The heterogeneity of the response among patients likely depends on a variable association of interindividual differences in the extension of ischemia, in the sensitivity of cardiac neuronal algogenic receptors and in the adenosine-mediated effects of dipyridamole on cardiac perception of pain and on electrophysiological characteristics of myocardial cells. 735 Cultural evolution of digital description of coronary artery disease severity potential of inducing myocardial ischemia during exercise stress echocardiography.