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Color-coded tissue Doppler assessment of the effects of acute ischemia on regional left ventricular function: comparison with sonomicrometry.

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Abstract

Echocardiographic assessment of regional left ventricular (LV) function usually consists of subjective visual inspection of endocardial movement and wall thickening. Color-coded tissue Doppler (TD) is a potential means to quantify regional LV function more objectively. Accordingly, in this study, color-coded TD was used to assess the regional effects of acute ischemia in an open-chest canine model of coronary occlusion, with implanted sonomicrometry length crystals as a standard of reference. Eight dogs were studied during baseline conditions and during left anterior descending coronary artery occlusion. Midventricular short-axis images were used to guide the color TD M-mode cursor through circumflex (septal) and left anterior descending (anterolateral) perfusion zones. Off-line conversion of endocardial time-velocity maps was performed. Peak systolic endocardial velocity by TD decreased from 4.4 +/- 1.4 cm/s to 1.8 +/- 1.5 cm/s with coronary occlusion (P < .05 versus baseline). Similar significant decreases in calculated systolic velocity by sonomicrometry occurred with ischemia from 11.1 +/- 3.8 mm/s to 8.2 +/- 1.2 mm/s (P < .05 versus baseline). Peak systolic velocity by TD was inversely correlated with end-systolic length by sonomicrometry as a measure of regional function (r = -0.77, P < .001). Time to peak systolic velocity increased with ischemia from 154 +/- 60 ms to 286 +/- 67 ms by TD and 200 +/- 60 ms to 320 +/- 30 ms by sonomicrometry (P < .05 versus baseline). The delay in time to peak systolic velocity by TD and sonomicrometry were correlated (r = 0.75, P < .001). In conclusion, color-coded TD echocardiography has the potential to quantify regional LV function during coronary ischemia.

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