Abstract 3383: Preserved Circumferential Function by 2D Speckle Tracking Determines the Favorable Improvement of Left Ventricular Geometry and Function After Cardiac Resynchronization Therapy
Background: Left ventricular (LV) reverse remodeling and improvement of systolic asynchrony in longitudinal direction were observed after cardiac resynchronization therapy (CRT). However, the change of myocardial deformation in circumferencial or radial direction is less clear. This study evaluated the effect of CRT on peak systolic circumferential strain, radial strain and torsion by 2D speckle tracking, a newly developed echocardiographic technology.
Methods: 37 patients received CRT (63±14 yrs, 29 males) and 37 normal controls with matched age and sex were enrolled. Serial echocardiography was performed at baseline and 3 months after CRT. 2D images of short-axis views at basal, papillary muscle and apical levels were analyzed for torsion (Tor), total circumferential (ε-circum) and radial strain (ε-radial).
Results: The ε-circum (20.9±7.7 vs 56.4±10.6%), ε-radial (30.3±18.3 vs 126.9±31.0%) and Tor (6.9±4.3 vs 16.8±5.3°) were markedly reduced in the patients (all p<0.001 vs controls). After CRT for 3 months, there were 19 responders of reverse remodeling (reduction of LV end-systolic volume ≥15%) who had higher baseline ε-circum than non-responders, while both ε-circum (p<0.005) and ε-radial (p<0.05) were only improved in responders. Surprisingly, Tor was not enhanced in responders, but was worsened in non-responders (p<0.05). Improvement of ε-circum correlated with increase in ejection fraction (r=0.51, p=0.001) and decrease in LV mid-cavity transverse diameter (r=-0.56, p<0.001). A baseline cutoff value of ε-circum ≥20% predicted a gain in ejection fraction ≥5%, with a sensitivity of 70% and a specificity of 71%; as well as a favorable reverse remodeling response, with a sensitivity of 63% and a specificity of 67%.
Conclusions: Responders of reverse remodeling after CRT showed improvement of both circumferential and radial strain, despite no change in torsion. Preserved ε-circum of ≥20% appeared useful to predict favorable geometric and functional responses after CRT.