Segmental and global longitudinal strain measurement by 2-dimensional speckle tracking echocardiography in severe rheumatic mitral stenosis

Abstract

Background: The present study aimed to detect subtle left ventricular (LV) dysfunction in patients with severe rheumatic mitral stenosis (MS) by measuring global and segmental longitudinal strain with a two-dimensional speckle tracking echocardiography (2D-STE) method.

Methods: In this case-control study, 65 patients with severe rheumatic MS and preserved ejection fraction (EF ≥ 50% measured by conventional echocardiographic methods) were compared with 31 otherwise healthy control subjects. All patients underwent LV strain measurement by the 2D-STE method in addition to conventional echocardiography using a VIVID S60 echocardiography device.

Results: Absolute strain values in myocardial segments 1-8, 10, and 12 (all basal, mid anterior, mid anteroseptal, mid inferior, and mid anterolateral segments) were significantly lower in patients with severe MS compared with the control group (P < 0.05 for all). The absolute global longitudinal strain (GLS) value was higher in the control group (-19.56 vs. -18.25; P = 0.006). After adjustment for age, gender, and systolic blood pressure, the difference in GLS between the two groups was as follows: mean difference=-1.16; 95% CI: -2.58-0.25; P = 0.110.

Conclusion: In patients with severe rheumatic MS and preserved EF, the absolute GLS tended to be lower than healthy controls. Furthermore, the segmental strain values of LV were significantly lower in most of the basal and some mid-myocardial segments. Further studies are warranted to investigate the underlying pathophysiology and clinical implications of this subclinical dysfunction in certain segments of patients with severe rheumatic MS.

Keywords: Left ventricular dysfunction; Mitral stenosis; Rheumatic Heart Disease; Strain measurement.

Fig. 1

Unadjusted (A) and adjusted (B) effect of severe MS on segmental longitudinal strains. In the green and yellow segments, the absolute strain value was lower in the rheumatic MS group than in the controls

Fig. 2

Bull’s eye plot in a patient with severe rheumatic MS showing reduced segmental longitudinal strain values in basal and some mid myocardial segments despite good global longitudinal strain. As presented in the image, three 2-D echocardiographic views, including 4, 3, and 2 chamber apical views with a focus on LV, were used to assess global and longitudinal strain values. To perform, in each view, three points were plotted manually at the base of each opposing wall as well as the apex using a point-and-click technique, and then the endocardial border was automatically traced by the software. The software divides the region of interest in each view into six segments, and the quality of tracing of each segment is automatically scored as either acceptable or unacceptable with the possibility of further correction manually. Finally, the software calculates global and segmental strains, displaying the values. (The figure is only for demonstration of the technique and was not taken from an included patient in the study)