266 Transient radial myocardial dysfunction in non ischemic segment

Abstract

Purpose In some patients, extensive myocardial dysfunction may be observed during acute coronary syndromes despite limited coronary lesions. Mechanism of depressed contractility during ischemia in remote segments is unclear. In the present study, we addressed the changes in myocardial deformation in remote segments during acute experimental ischemia. Methods Acute myocardial ischemia was induced in 9 anesthetized pigs by balloon coronary occlusion (left coronary descending artery, n=6). Radial and circumferential strain by speckle tracking were computed in the 6 mid short axis segment using 2D echocardiography data acquired at 5’, 15’, 30’and 60’of induced ischemia. Results Reduced in peak circumferential (−16%±2 vs. –6±2% p=0.04) and radial (45±5% vs. 17±6 p=0.002) strain occurred early after 5’of coronary occlusion and persisted during ischemia. Interestingly, reduced in peak radial strain (45±4% vs. 22±5% p=0.0005) was also observed in control segments (Figure) during the first stage of ischemia (5’). Compared to ischemic segments, impaired contraction in control segments was brief and recovered after 15’ of ischemia. Importantly only radial but not circumferential strain was affected in control segments. Conclusions A brief reduction in radial motion was observed during acute myocardial ischemia in control segments. This may explain the occurrence of transient and extensive myocardial dysfunction during acute coronary syndromes despite limited lesions. Download : Download full-size image