Effect of cardiac resynchronization therapy on left atrial appendage function and pulmonary venous flow pattern

Abstract

Background Previous studies have shown improvement in left ventricular function and development of the reverse remodeling in the left ventricle and left atrium after cardiac resynchronization therapy (CRT). The aim of this study was to investigate the effect of CRT on left atrial appendage (LAA) function and pulmonary venous flow pattern. Methods Eighteen patients with systolic heart failure and complete left bundle branch block underwent implantation of biventricular pacemaker devices. In order to follow changes in LAA, transthoracic and transesophageal echocardiographic examinations were performed 1 week before and repeated 1 and 6 months after pacemaker implantation. Results CRT resulted in significant clinical improvement and decrease in NYHA functional class in 17 patients (94%). Maximum and minimum areas of left atrial appendage (LAAA max and LAAA min) decreased, with a concomitant increase in LAA ejection fraction. [LAAA max: from 4.6±2 to 4.2±1.8 cm 2 at the first ( P<0.001) and to 4.0±1.8 cm 2 at the sixth month ( P<0.001); LAAA min: from 2.7±1.3 to 2.3±1.2 cm 2 at the first ( P<0.001) and to 2.2±1.2 cm 2 at the sixth month ( P<0.001) and LAA ejection fraction: from 41±12% to 46±10% at the first ( P=0.007) and to 47±8% at the sixth month ( P=0.003)]. LAA active emptying and filling flow and pulmonary venous systolic velocities also increased after CRT. The appendage active emptying velocity correlated significantly with left ventricular ejection fraction ( r=0.50, P=0.002), LAA ejection fraction ( r=0.51, P=0.002), left atrial maximal volume, LAV max ( r=−0.44, P=0.007), left atrial minimal volume, LAV min ( r=−0.50, P=0.002) and pulmonary vein systolic flow velocity ( r=0.33, P=0.05). Conclusion Treatment of heart failure by CRT results with marked improvements in LAA function and increases pulmonary venous systolic velocity.