Impact of Geometry of Left Ventricular Outflow Tract on Left Ventricular Diastolic Transmitral Inflow Doppler Patterns

ABSTRACT

BACKGROUND: Aging is an important factor to determine transmitral inflow velocity pattern. Cardiac geometry such as left ventricular (LV) volume, mass and left ventricular outflow tract (LVOT) was also changed with age. The aim of this study was to assess the impact of geometric change of LVOT on transmitral inflow velocity pattern excluding a factor of age. METHODS: Healthy 115 (61 men, 37+/-15 years) individuals were enrolled. Echocardiography was performed to measure LV mass, thickness, left atrial (LA) size, aortoseptal angle (ASA), early (E) and late (A) transmitral inflow velocity, and deceleration time (DT). ASA was measured at mid-diastole in apical long-axis view according to a method as the open angle between the edge of the interventricular septum and axis perpendicular to the aortic annulus. The relation between transmitral inflow velocity pattern and LV geometric parameters was analyzed by regression analysis. RESULTS: Simple regression analysis demonstrated a significant correlation between transmitral inflow parameters with age and geometric parameters (ASA, LA size and LV mass index). Multiple regression analysis, taking into consideration age, ASA, LA size and LV mass index showed that only age was an independent predictor for E, A, DT, and E/A ratio (r2=0.210, Beta coefficient (beta)=0.459, p<0.001;r2=0.427, beta=0.654, p<0.001;r2=0.227, beta=-0.476, p<0.001;r2=0.436, beta=-0.661, p<0.001, respectively). But, excluding age, ASA was an independent predictor for E, A, DT, and E/A ratio (r2=0.151, beta=0.389, p<0.001;r2=0.294, beta=0.542, p<0.001;r2=0.227, beta=-0.476, p<0.001;r2=0.260, beta=0.509, p<0.001, respectively). CONCLUSION: ASA, a parameter of LVOT geometry, might be an important factor related to transmitral inflow velocity pattern excluding a factor of age.