Abstract 8846: Relationship Between Left Appendage Volume and Function, and Left Atrial Function: A Real-Time Three-Dimensional Transesophageal Echocardiography Study

Abstract

Background: Left atrial appendage (LAA) has multilobed complicated structure. Therefore, attempts to quantitate LAA size and function by 2-dimensional (2D) methods may not offer acurate evaluations. Recent development of real-time 3-dimensional transesophageal echocardiography (RT3D-TEE) has enabled us to examine morphology and to determine absolute volumes of LAA without geometrical assumptions. The association between LAA volume and function, and left ventricular (LV) and left atrial (LA) function has not been well investigated. Methods: Eighty-nine pts who underwent RT3D-TEE for evaluation of thrombus in LAA were studied. All measurements were performed off-line software. LAA maximal (max) orifice area, max and minimal (min) volumes, and ejection fraction (LAAEF) were assessed (Figure). LAA emptying flow velocity was also measured. We determined max and min LV and LA volume (LAV) by the Simpson method with 2D transthoracic echocardiography. LAV total emptying fraction (LAEF) was determined as (max LAV - min LAV)/ max LAV. Similarly in pts with sinus rhythm, active and passive LAEF were calculated. Pulsed Doppler E, tissue Doppler E' and E/E' were also measured. Additionally, as a parameter of LA compliance, we measured time velocity integral of systolic pulmonary venous flow (SVTI). Results: LAA volume was significantly correlated with max LAV, min LAV, E/E' and SVTI. LAAEF was significantly correlated with age, all LAEFs, E/E' and SVTI. There was no correlation between LAA volume and LAAEF (Table). Multiple regression analysis revealed that max LAV and E/E' (both, p<0.01) were independently correlated with 3D derived LAA volume, and active and passive LAEF were independently correlated with 3D derived LAAEF (p=0.02 and p=0.05, respectively). Conclusion: LAA volume determined by RT3D-TEE was independently associated with E/E' and max LA volume. Moreover, LAA function was independently associated LA function.