Abstract 12721: Compensatory Mechanism in HCM Patients With Preserved LV Ejection Fraction Determined by 2D Speckle Tracking Echocardiographic LV Myocardial Strain Gradient Using a Novel Multi-Layer Technique
Introduction: A novel multi-layer technique on speckle tracking transthoracic echocardiography (TTE) can achieve quantitative strain measurements of all, subendocardial, and subepicardial layer of left ventricle (LV), respectively.
Aim: To evaluate compensatory mechanism in hypertrophic cardiomyopathy (HCM) subjects with preserved LV ejection fraction (EF), we measured myocardial strain gradient by 2D LV global longitudinal (GLS) and circumferential strain (GCS) using a multi-layer technique on speckle tracking TTE.
Methods: 60 subjects (40 HCM (30 male; age 62 ± 15 years, LV EF >50%, and 20 age matched controls (10 male; age 59 ± 10 years)) underwent TTE (Vivid E9, GE). Apical 4-, 2-, 3-chamber views for GLS and parasternal short-axis views at the level of mitral valve, papillary muscle, and apex for GCS were acquired. We defined myocardial strain gradient as the ratio of subendocardial strain to subepicardial strain.
Results: GLS from each view were significantly smaller in HCM than controls in all, subendocardial, and subepicardial layers. GCS at all levels were significantly smaller in HCM than controls in all and subepicardial layer; however there were no significant differences in subendocardial GCS between both groups at mitral valve and papillary muscle levels. GLS gradient was significant greater in HCM than controls in GLS from 4 chamber views. GCS gradients were significantly greater in HCM than in controls at all levels. In HCM, subendocardial GCS at mitral valve and papillary muscle levels significantly positive correlated with LV EF (R=0.446, 0.34, respectively) and subendocardial GLS from 4-, and 2- chamber views, and subendocardial GCS at mitral valve and papillary muscles levels significantly negatively and GCS gradients at mitral valve and papillary muscle levels significantly positively correlated with interventricular septum thickness in end diastole (R=-0.44, -0.347, -0.335, -0.359, 0.363, and 0.373, respectively).
Conclusions: In HCM subjects with preserved LV EF, GLS was significantly smaller than in controls, but GLS and GCS gradients tended to be greater than controls. We speculate that in HCM, subendocardial GCS was maintained in compensation for subendocardial GLS decrement; thus GCS gradient may increase.
Author Disclosures: K. Ozawa: None. N. Funabashi: None. H. Takaoka: None. Y. Kobayashi: None.
- © 2014 by American Heart Association, Inc.