M-mode speckle tracking--a novel echocardiographic approach to assess left ventricular torsional deformation.

BACKGROUND

Speckle tracking echocardiography (STE) requires special image processing for complex assessment of left ventricular (LV) function, including strain and rotation.

AIM

To evaluate a novel M-mode STE technique as a readily applicable approach, providing potential insights into LV deformation.

METHODS

Fifty one patients (mean age 52 +/- 14 years, 24 women) with normal or impaired LV function (mean LVEF 51 +/- 16%, range between 14% and 66%) were studied. Left ventricular rotation at mitral valve and apical level was measured using dedicated conventional STE software. Grey-scale short axis digital loops at mitral valve level were also used to obtain M-mode STE images, presenting the movement of LV wall speckles along the cursor, with the LV cavity left out. Then, the distance of peak systolic shift (PSS) was measured for one selected speckle.

RESULTS

Mean rotation at mitral valve level was 7.4 +/- 3.1 degrees , apical rotation was 7.6 +/- 6.4 degrees and LV torsion was 14.9 +/- 7.1 degrees . Measurement of PSS with a novel M-mode STE approach was feasible in all patients, producing a mean value of 7 +/- 2 mm. Subsequently, two subsets with PSS of less than 7 mm and PSS equal to or above 7 mm showed a significant difference between mean LV torsion of 10.7 degrees and 17.0 degrees , respectively (p = 0.002). In the ROC analysis, PSS cut-off value of less than or equal to 7 mm yielded a sensitivity of 92% and a specificity of 61% to predict LV torsion < 10.7 degrees (p < 0.0001).

CONCLUSIONS

M-mode STE appears to be a feasible approach to detect movement of speckles and to measure PSS within the LV inferior and septal wall in short axis view images. PSS cut-off value of less than 7 mm indicates significantly lower LV torsion. Further studies are required to assess the potential role of M-mode STE in cardiac imaging.