Effect of contrast on systolic myocardial ultrasound color-Doppler velocity

Intravenously distributed ultrasound contrast increases echoes from the normally low echogenic bloodpool and myocardial perfusion imaging is developing. However the microspheres used are potential endothelial stimulators as well as nonlinear scatterers. Tissue Doppler is developed to detect velocities of myocardial motion, which are in the same range as perfusion flow velocities. The effect of contrast is not evaluated. We performed echocardiography in 12 patients with ischemic heart disease before and immediately after a slow intravenous infusion of 27 ml Optison^® using color myocardial Doppler imaging (GE Vingmed systemV). Longitudinal basal systolic velocities and their integrals were analyzed in digitally stored cineloops. Peak mean velocity increased 10% by contrast from mean 5.2 ± 1.8 (SD) to 5.7 ± 2.3 cm/s (p=0.02, confidence interval 2-16%) but integral did not change (0.8 ± 0.4 cm). Contrast has no effect on blood pressure or heart rate in used dose. It is therefore of interest to further evaluate if this increase in velocity; a) is a methodological effect that may be used to detect contrast within myocardium (and thereby perfusion/blood volume), or b) is secondary to increased flow and motion caused by endothelial and vascular effects from the contrast microspheres. Either have important methodological, physiological and clinical impact.