Assessing functional mitral regurgitation with exercise echocardiography: rationale and clinical applications

Background

Strain, and particularly Longitudinal Peak Systolic Strain (LPSS), plays a role in investigating the segmental and overall contractility of the heart which is a particularly interesting feature in athletes in whom regular training determines several morphological and functional modifications in both the ventricles, that normally work at different loads. Speckle tracking techniques assess the LPSS of LV and RV from B-mode imaging in real time, with uniform accuracy in all segments, and can verify the possible dissimilar segmental contributions of the two chambers to overall myocardial contraction. The aim of the study is to quantify the LPSS in real time in both the ventricles in order to estimate any possible different deformation properties in them during a systolic period.

Methods

32 subjects (20 athletes and 18 controls) were submitted to a standard echocardiographic examination at rest and after a Hand Grip (HG) stress. From a four-chamber-view image, the LPSS parameter was measured with Speckle Tracking analysis in the basal and medium-apical segments of the two ventricles, at rest and after HG.

Results

In both athletes and controls, LPSS values were significantly higher in the RV of athletes (RV LPSS^{medium-apical} -23.87 ± 4.94;^{basalfreewall} -25.04 ± 4.12 at rest) and controls (RV LPSS^{medium-apical} -25.21 ± 4.97;^{basalfreewall} -28.69 ± 4.62 at rest) than in the LV of both (athletes LV LPSS^{medium-apical} -18.14 ± 4.16;^{basallateralwall} -16.05 ± 12.32; controls^{medium-apical} -18.81 ± 2.64;^{basallateralwall} -19.74 ± 3.84) With the HG test a significant enhancement of the LPSS(with P <.05) in the medium-apical segments of LV and RV was evident, but only in athletes; there was no modification of the standard echo-parameters in either group.

Conclusion

ST analysis is an easy method for investigating the contractility of the RV through deformation parameters, showing greater involvement of the RV than LV at rest. In athletes only, after isometric stress the two ventricles show particular myocardial deformation properties of the regions around the apex where the curvature of the wall is more marked. The clinical application of this new approach in athletes and normal subjects requires further investigation.