Left Atrial Appendage Blood Flow Determined by Transesophageal Echocardiography in Patients with Complete Atrioventricular Block

Abstract

Function of the left atrial appendage (LAA) represented by LAA outflow is an important predictor for thrombus formation in patients with nonrheumatic atrial fibrillation, but the pattern of LAA flow in patients with complete atrioventricular (AV) block has rarely been studied. Twenty-one patients with complete AV block and an implanted WI or WIR pacemaker were studied with transesophageal echocardiography. The LAA outflow velocity obtained during the ventricular diastolic phase was significantly higher than that obtained during the ventricular systolic phase (41.5 ± 6.0vs. 34.9 ± 9.7cm/s; p < 0.001). The LAA inflow velocity obtained during the ventricular diastolic phase was also significantly higher than that obtained during the ventricular systolic phase (29.9 ± 7.8 vs. 26.4 ± 5.3 cm/s; p < 0.01). In addition, the LAA outflow and inflow velocity time integrals during the ventricular diastolic phase were significantly higher than those during the ventricular systolic phase (4.66 ± 0.96 vs. 4.08 ± 1.05 cm, p < 0.01, and 2.81 ± 0.77 vs. 2.56 ± 0.65 cm, p < 0.05, respectively). Thus, due to both diastolic augmentation of the LAA flow related to active atrial contraction and minor early diastolic LAA flow formation, left ventricle diastolic function might have some influence on LAA flow. This may have implications for the pathogenesis of LAA thrombi in left ventricular dysfunction.

Influence of Left Ventricular Diastole on Left Atrial Appendage Blood Flow in Patients with Nonrheumatic Atrial Fibrillation

“…However, several fibrillatory waves of LAA outflow were augmented during ventricular diastolic phase in comparison with those during ventricular sys tolic phase. A similar phenomenon was also noted in patients with complete atrioventricular block [23]. Due to a decreased active LAA contraction force during AF, the influence of left ventricular diastole on LAA flow be comes obvious.…”