EVALUATION OF LEFT ATRIAL APPENDAGE FUNCTION BY MEASUREMENT OF CHANGES IN FLOW VELOCITY PATTERNS AFTER ELECTRICAL CARDIOVERSION IN PATIENTSWITH 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 ire directing blood flow to the left atrial main cham ber and left ventricle. The study consisted of 26 patients with chroni c isolated atrial fibrillation treated with electrical cardioversion a nd 20 normal controls in sinus rhythm. Using transthoracic and transes ophageal Doppler echocardiography, we recorded transmitral, pulmonary venous, and LAA flow velocity patterns before, 24 hours, and 1 week af ter cordioversion in all subjects. In the 15 patients who underwent su ccessful cardioversion, the maximal LAA area 24 hours after cardiovers ion was smellier than the area before cardioversion, whereas LAA eject ion fraction during atrial systole and peak atrial systolic emptying v elocity of the LAA flow were lower 24 hours after cardioversion than t hose in the control group. One week after cardioversion, maximal LAA a rea and LAA peak atrial systolic emptying velocity were restored to le vels 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 negati vely and positively with LAA ejection fraction, respectively, 24 hours and 1 week after cardioversion. These results suggest that LAA and th e left atrial main chamber show stunning 24 hours after cardioversion, and the atrial systolic emptying wave of LAA flow is generated by act ive LAA contraction. (C) 1997 by Excerpta Medica, Inc.