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

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 (LAAAmax and LAAAmin) decreased, with a concomitant increase in LAA ejection fraction. [LAAAmax: from 4.6±2 to 4.2±1.8 cm2 at the first (P<0.001) and to 4.0±1.8 cm2 at the sixth month (P<0.001); LAAAmin: from 2.7±1.3 to 2.3±1.2 cm2 at the first (P<0.001) and to 2.2±1.2 cm2 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, LAVmax (r=−0.44, P=0.007), left atrial minimal volume, LAVmin (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.