906-64 Doppler Tissue Imaging of Left Ventricular Myocardium — Initial Results During Pharmacologic Stress

Abstract

The new technique of Doppler tissue imaging (DTI) theoretically has the potential to quantify regional myocardial function. To determine the pattern of normal and ischemic LV contraction and relaxation during pharmacologic stress we studied DTI during a Dobutamin stress test (incremental steps from 5 up to 40 mcg/kg/min per 5’) in 18 patients with suspected ischemic heart disease using coronary angiography (CA) and conventional stress echocardiography (SE) for reference. We used a conventional ultrasound equipment (Acuson 128 XP) with software modifications which allowed also the display of myocardial regional velocities by colour Doppler (CD) and by the pulsed Doppler mode. Velocity patterns were analyzed in representative regions for each vascular bed as for peak velocities of contraction (V c ) and relaxation (V R ) and were compared to the echocardiographic score index in a 14 segment model. DTI images in CD and pulsed wave Doppler could be obtained in all patients. The analysis of 2-dimensional CD images gave similar morphological regional information as SE. Analysis, however, proved difficult in the presence of high heart rates due to low frame rates. In the 7 patients without coronary artery disease, there was a significant increase of V C (9.3 ± 4.1 to 13.1 ± 5.3 cm/s) and V R (-10.4 ± 2.6 to -148 ± 4.2 cm/s) during peak stress (p < 0.01). In infarcted beds, V c and V R were low both before and during peak stress. In regions supplied by an artery with < 50% stenosis, V R more than V c decreased during peak stress. Sensitivity for the diagnosis of coronary artery disease was 81% using SE and 92% using DTI. DTI provides quantification of regional LV contraction and relaxation and thus augments ultrasound stress studies.