Abstract 11093: Layer-specific Quantification of Myocardial Deformation by Strain Echocardiography May Reveal the Mechanism of Preserved Left Ventricular Ejection Fraction in Patients With Hypertrophic Cardiomyopathy

Abstract

Purpose: We aimed to evaluate compensatory mechanisms in hypertrophic cardiomyopathy (HCM) patients (pts) with preserved left-ventricular (LV) ejection fraction (EF). Methods: Speckle-tracking echocardiography (Vivid E9, GE) was performed in 50 HCM with preserved LV EF (38 m; 49± 14 y, all LV EF > 55%) and 50 age, gender matched controls (38 m; 49±12 y). The global and segmental longitudinal (LS), circumferential (CS) and radial strain (RS) strains of endocardia (End), mid-wall and epicardia layers were analyzed using a novel layer-specific TTE. The ratio of End to epicardia strain (End/Epi) was calculated. Results: The LV EF were similar in pts and controls (64±8 vs 64±7 %, p=0.95). The diastolic function was significantly impaired in HCM pts compared with controls (E/E’:18.4±8.4 vs 8.6 ±2.4, p<0.0001). The absolute value of LS and CS was reserved at apical End layers (-34±7 vs -35±6, p=0.44); the remaining segments and LV global LS and CS of three layers were significantly smaller (LS,-16±5 vs -22±3; CS -24±8 vs -33±7; p<0.0001), and LS and CS End/Epi (1.7±0.3 vs 1.3±0.1, 3.4±1.1 vs 1.7±0.2 respectively, P <0.0001) was significantly higher in HCM pts than in controls. The RS and LV twist were preserved in all LV segments (27±10 vs 24±12, p=0.19; 20±8 vs 18±5, p=0.33; respectively). In HCM pts, the LV LS value at basal and middle levels revealed significant negative correlations with LV relative wall thickness (r=–0.65, –0.59 and –0.60, –0.54, respectively , p< 0.0001); and mild negative correlations (r=-0.33,-0.29, p<0.0001). The LV CS value at all levels revealed mild correlations with relative wall thickness (r=-0.22, p<0.05) . The LS were significantly reduced at the hypertrophic segments (Figure). Conclusions: In HCM patients with preserved LVEF, LV GLS was impaired, but apical End LS and basal End CS, LV RS as well as LV twist were maintained as the compensation for reduction LV LS and CS. The Bull’s eye of LS may help us to localize the lesion segments and define the type of HCM.