Evaluation of Left Atrial Appendage Function by Measurement of Changes in Flow Velocity Patterns After Electrical Cardioversion in Patients With Isolated Atrial Fibrillation

We investigated temporary changes in left atrial appendage (LAA) flow velocity patterns in patients undergoing electrical cardioversion for chronic isolated atrial fibrillation, and evaluated the role of active LAA contraction in directing blood flow to the left atrial main chamber and left ventricle. The study consisted of 26 patients with chronic isolated atrial fibrillation treated with electrical cardioversion and 20 normal controls in sinus rhythm. Using transthoracic and transesophageal Doppler echocardiography, we recorded transmitral, pulmonary venous, and LAA flow velocity patterns before, 24 hours, and 1 week after cardioversion in all subjects. In the 15 patients who underwent successful cardioversion, the maximal LAA area 24 hours after cardioversion was smaller than the area before cardioversion, whereas LAA ejection fraction during atrial systole and peak atrial systolic emptying velocity of the LAA flow were lower 24 hours after cardioversion than those in the control group. One week after cardioversion, maximal LAA area and LAA peak atrial systolic emptying velocity were restored to levels approximately equivalent to those in the control group, although LAA ejection fraction was lower than in the control group. Maximal LAA area and LAA peak atrial systolic emptying velocity correlated negatively and positively with LAA ejection fraction, respectively, 24 hours and 1 week after cardioversion. These results suggest that LAA and the left atrial main chamber show stunning 24 hours after cardioversion, and the atrial systolic emptying wave of LAA flow is generated by active LAA contraction. estigated temporary changes in the left atrial appendage (LAA) flow velocity pattern before, 24 hours, and 1 week after electrical cardioversion in 15 patients with chronic isolated atrial fibrillation converted to sinus rhythm. The results that the LAA ejection fraction and the peak LAA atrial systolic emptying velocity decreased 24 hours after cardioversion and recovered 1 week after cardioversion, and the maximal LAA area and the peak LAA atrial systolic emptying velocity correlated with the LAA ejection fraction, respectively, suggest that the LAA is temporarily stunned 24 hours after cardioversion, and that the LAA atrial systolic emptying wave is generated by active LAA contraction.