The Association of Left Ventricular Hypertrophy with Intraventricular Dyssynchrony at Rest and during Exercise in Hypertensive Patients

Interrelationships between Peak Strain Dispersion, Myocardial Work Indices, Isovolumetric Relaxation and Systolic-Diastolic Coupling in Middle-Aged Healthy Subjects

In echocardiography, peak strain dispersion (PSD) is the standard deviation of the time to peak longitudinal strain for each left ventricular (LV) segment during systole. It assesses the coordination and synchrony of LV segment contractility. Global work efficiency (GWE) and global wasted work (GWW) quantify LV myocardial work and, if impaired, the coupling between LV systolic contraction and early relaxation. Isovolumetric relaxation (IVRT) measures the duration of initial LV relaxation, while the ratio of early diastolic recoil to systolic excursion (E'VTI/S'VTI) describes systolic-diastolic coupling. We evaluated these parameters in 69 healthy subjects and found that PSD correlated negatively with GWE (r = -0.49, p < 0.0001) and E'VTI/S'VTI (r = -0.44, p = 0.0002), but positively with GWW (r = 0.4, p = 0.0007) and IVRT (r = 0.53, p < 0.0001). GWE correlated negatively with GWW (r = -0.94, p < 0.0001) and IVRT (r = -0.30, p = 0.0127), but positively with E'VTI/S'VTI (r = 0.3, p = 0.0132). In addition, E'VTI/S'VTI was negatively correlated with GWW (r = -0.35, p = 0.0032) and IVRT (r = -0.36, p = 0.0024). These associations remained significant after adjustment for sex, age and LV mass index of the subjects. In conclusion, there is an interaction between measures of LV asynchrony, myocardial work, diastolic function and its systolic-diastolic coupling in middle-aged healthy subjects. The clinical value of these interactions requires further investigation.

Changes in mechanical dyssynchrony in severe aortic stenosis patients undergoing transcatheter aortic valve replacement

INTRODUCTION

Aortic stenosis (AS) imposes a significant afterload on the left ventricle, but regional manifestations of the overall load may not be uniform, leading to mechanical dyssynchrony. Accordingly, we evaluated the prevalence of dyssynchrony in patients with severe AS at baseline as well as changes after transfemoral aortic valve replacement (TAVR).

METHODS

This study is a retrospective analysis of 225 patients in sinus rhythm who underwent TAVR for severe AS, in whom inter-ventricular and intra-ventricular dyssynchrony were measured at baseline, discharge, 1 month, and 1 year. Inter-ventricular dyssynchrony was defined as the difference between left and right ventricular pre-ejection intervals; intra-ventricular dyssynchrony was defined as the difference between time to peak systolic velocity of the basal septal and lateral segments. Patients were further stratified into those with QRS <120 ms or >120 ms.

RESULTS

At baseline, a quarter of patients met the criterion for significant inter-ventricular dyssynchrony, and a third had evidence of intra-ventricular dyssynchrony. Both decreased after TAVR although only the intra-ventricular dyssynchrony reached statistical significance. The interplay between QRS duration and changes in inter- and intra-ventricular dyssynchrony are also explored.

CONCLUSIONS

In patients with severe AS, there was evidence of mechanical dyssynchrony that is improved post-TAVR. Whether dyssynchrony is clinically and prognostically significant, and if it represents a potential target for additional therapy remains to be studied.