[Quantification of longitudinal myocardial velocities by Doppler tissue imaging during dobutamine echocardiography]

Doppler tissue imaging has been suggested to be a valuable method for the diagnosis of myocardial ischaemia during dobutamine echocardiography. The authors studied this mode of investigation in 49 consecutive patients (average age 60 +/- 12 years) referred for dobutamine stress echocardiography and who had undergone coronary angiography. The stress echo was carried out according to a standard protocol (5 to 40 m g/kg/min +/- atropine) with additional acquisition of 3 apical views (4, 2 and 3 chambers) with colour Doppler tissue imaging. Analysis of systolic and diastolic myocardial velocities was performed afterwards from digitised data. The different Doppler tissue parameters were measured in 12 left ventricular segments (excluding the apical segments) for each dosage of dobutamine: peak systolic velocity (S), Q-S duration, systolic velocity time integral (ITVS), peak early diastolic velocity (E), peak end diastolic velocity (A). These parameters were analysed throughout the stress for each segment without significant coronary stenosis to define normal values. ROC curves were constructed to determine threshold values of relative changes of velocity (between maximal dobutamine dosage and basal conditions) to improve detection of ischaemia in a segment with coronary stenosis (vessel diameter reduction > or = 70%). Similar diagnostic performances were observed with different systolic and diastolic parameters. The feasibility of measurement of diastolic velocities was, however, reduced (from 29% to 49%). The diagnostic accuracy of each parameter was the same for each vessel territory. A satisfactory concordance was observed between 2D echocardiography and Doppler tissue imaging for the detection of significant coronary stenosis in an analysis by vascular territory. The authors conclude that analysis of myocardial velocities during dobutamine stress echocardiography is feasible. It may be a useful complement for the detection of coronary stenosis during pharmacological stress echocardiography.