Accuracy of measuring mitral annular velocity by 2D speckle tracking imaging

Recent developments in 2D speckle tracking imaging allow not only measurements of regional myocardial strain, but also velocities of the mitral annulus. The aim of this study was to determine the accuracy of speckle tracking derived mitral annulus velocity compared with conventional pulsed wave Doppler measurements.

2D speckle tracking was acquired from the apical 4-chamber view (QLab, Speckle SQ, Philips, Andover, MA) in 169 subjects. While using texture tracking, two small regions of interest (ROIs) were placed in the septal (IVS) and lateral corners (LAT) of the mitral annulus. The software automatically tracked the ROIs frame-by-frame, yielding regional mean velocity curves of the mitral annulus throughout the cardiac cycle (synthetic pulsed wave Doppler; SPW). From these curves, peak systolic, early- and late-diastolic velocities of the mitral annulus (S'-SPW, E'-SPW, and A'-SPW) were measured. Peak systolic, early- and late-diastolic velocity in the mitral annulus (S', E', and A') by conventional pulsed wave tissue Doppler tracing were also obtained.

Adequate ROI tracking was observed in 150/169 subjects in IVS and 139/169 subjects in LAT of the mitral annulus. All annular velocities derived from SPW were significantly lower than corresponding velocities obtained from conventional method in both IVS and LAT regions of the mitral annulus. However, significant correlation between S' (E', A')-SPW and S' (E', A') was observed. In particular, a good correlation between E'-SPW and E' was noted in both IVS (r=0.89, P<0.001) and LAT (r=0.85, P<0.001) regions of the mitral annulus. If we defined E/E'-SPW in IVS>26 for predicting E/E' in IVS>15, sensitivity, specificity, and accuracy were 83%, 97%, and 94%, respectively. E/E'-SPW in LAT>13 had a 94% sensitivity, 92% specificity, and 93% accuracy for predicting E/E' in LAT>10.

The values of annular velocities by SPW were significantly lower compared to those assessed by traditional tissue velocities. However, new cut-off values of E/E'-SPW for predicting elevated LV filling pressure highly correlated with traditional parameters. 2D speckle tracking imaging provides another strategy for evaluating LV filling pressures.