Left Ventricular Longitudinal and Circumferential Layer‐Specific Myocardial Strains and Their Determinants in Healthy Subjects

BACKGROUND: The reference values and impact of physiologic variables on echocardiographic quantification of left ventricular (LV) longitudinal and circumferential layer-specific myocardial strains in large series of healthy persons remain unknown. This study prospectively investigated the impact of age, gender, and other physiologic parameters on LV longitudinal and circumferential layer-specific myocardial strains. METHODS: 119 healthy volunteers (age range, 22-76; 50% women) underwent echocardiography. Short-axis (for circumferential strain) and apical (for longitudinal strain) views were analyzed using modified speckle tracking software enabling the analysis of strains in three myocardial layers. RESULTS: In normal subjects, longitudinal and circumferential strain was highest in the endocardium and lowest in the epicardium, longitudinal and circumferential three-layer strain was highest in the apex and lowest in the base. The mean global longitudinal strain in the endocardial layer (GLS-endo), in the mid-myocardial layer (GLS-mid) and in the epicardial layer (GLS-epi) were -24.3 ± 3.1%, -21.3 ± 2.9%, and -18.9 ± 2.8%, respectively. Gender, HR, and SV (stroke volume) were independent predictors of GLS-endo, GLS-mid, and GLS-epi. The mean global circumferential strain in the endocardial layer (GCS-endo), in the mid-myocardial layer (GCS-mid) and in the epicardial layer (GCS-epi) were -34.3 ± 4.4%, -20.5 ± 3.0%, and -11.8 ± 2.7%, respectively. HR independently predicted GCS-endo, GCS-mid, and GCS-epi. CONCLUSIONS: Three-layer analysis of longitudinal and circumferential strain using two-dimensional speckle tracking imaging (2DSTI) can be performed on a clinical basis and may become an important method for the assessment of real time, quantitative global, and regional LV function.