Effect of Cardiac Resynchronization Therapy on Left Atrial Appendage Function and PulmonaryVenous Flow Pattern

Previous studies have shown improvement in left ventricular function and development of the reverse remodeling in 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 function and pulmonary venous flow pattern. Eighteen patients with systolic heart failure and complete left bundle-branch block underwent implantation of biventricular pacemaker devices. In order to follow changes in left atrial appendage, transthoracic and transesophageal echocardiographic examinations were performed one week before, and repeated one and six months after pacemaker implantation. CRT resulted with significant clinical improvement and decrease in NYHA functional class in 17 patients (94%). Maximum and minimum areas of left atrial appendage (LAAmax and LAAmin) decreased, with a concomitant increase in LAA ejection fraction. [LAAmax: from 4.6 ± 2 cm2 to 4.2 ± 1.8 cm2 at the 1st (p<0.001) and to 4.0 ± 1.8 cm2 at the 6th month (p<0.001); LAAmin: from 2.7 ± 1.3 cm2 to 2.3 ± 1.2 cm2 at the 1st (p<0.001) and to 2.2 ±1.2 cm2 at the 6th month (p<0.001) and LAA ejection fraction: from 41 ± 12% to 46 ± 10% at the 1st (p=0.007) and to 47 ± 8% at the 6th month (p=0.003)]. Left atrial appendage 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 maximum volume (r=-0.44, p=0.007), left atrial minimum volume (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 in marked improvement in LAA functions and increases pulmonary venous systolic velocity. (Türk Kardiyol Dern Arş 2004; 32: 91-98)