Pre-ejection tissue-Doppler velocity changes during low dose dobutamine stress predict segmental myocardial viability.

INTRODUCTION We tested the hypothesis that low dose dobutamine stress echocardiography (LDDSE) combined with tissue Doppler imaging (TDI) can be used for the quantitative assessment of the content of viable myocardium. METHODS Forty-one patients with coronary artery disease and left ventricular dysfunction (ejection fraction < or =40%), already scheduled for revascularisation, underwent echocardiographic assessment of viability at rest and during low-dose dobutamine infusion (2.5 microg/kg/min up to 10 micro/kg/min) at two time points, 2 days before and 3 months after revascularisation. Pulsed-wave TDI was performed at rest and during LDDSE; ejection (Ej), pre-ejection (pre-Ej) and diastolic velocities (Ea, Aa) were recorded at rest and at 10 microg/kg/min dobutamine infusion. Recovery of regional function was defined as improvement of one or more grades 3 months post-revascularisation. RESULTS A total of 112 vessels were revascularised. Out of 492 segments, 274 segments were characterised as viable and the remaining 218 as non-viable, according to postoperative functional myocardial recovery. Conventional qualitative LDDSE showed a sensitivity of 78% and specificity of 85% in predicting myocardial recovery. Ej, pre-Ej and Ea velocities increased significantly during LDDSE, while Aa velocity did not change significantly. Using ROC curves, the optimal cut-off value for viability assessment was an increase of 0.5 cm/s in Ej during LDDSE (80% sensitivity and 88% specificity, area under the curve 0.801), 0.6 cm/s in pre-Ej (91% sensitivity and 90% specificity, area under the curve 0.890), and 0.44 cm/s in Ea velocity (80% sensitivity and 81% specificity, area under the curve 0.780). CONCLUSIONS Despite its technical limitations, the measurement of ejection and pre-ejection velocities during dobutamine stimulation appears to be an effective way of predicting myocardial segmental recovery following reperfusion.