EFFECTS OF BALLOON MITRAL VALVULOPLASTY ON LEFT ATRIAL FUNCTION IN MITRAL-STENOSIS AS ASSESSED BY PRESSURE-AREA RELATION

Objectives. This study sought to investigate the changes induced on th e pressure-area relation of the left atrium in patients with mitral st enosis after percutaneous balloon mitral valvulo-plasty. Background. L eft atrial (LA) function is influenced by changes in LA afterload. The latter is increased in mitral stenosis as a result of increased resis tance to blood flow imposed by the stenotic mitral valve. Methods. We studied the effects of acute alterations of LA afterload induced by re trograde nontransseptal balloon mitral valvuloplasty (RNBMV) on LA fun ction in patients with mitral stenosis. LA pressure-area relations wer e obtained in 15 patients with mitral stenosis (8 with sinus rhythm, 7 with atrial fibrillation) before and after valvuloplasty, as well as in 15 normal subjects. LA pressure was recorded by a catheter-tipped m icromanometer introduced retrogradely into the left atrium while LA ar ea was recorded simultaneously using acoustic quantification. The area s of the A and V loops of the pressure-area relation as well as the LA chamber stiffness constant were calculated. Results. Balloon valvulop lasty resulted in a significant increase in mitral valve area (p < 0.0 01) and a substantial reduction of the mean transmitral pressure gradi ent (p < 0.001) and mean LA pressure (p < 0.001). The area of the A lo op in patients with sinus rhythm and the area of the V loop in those w ith atrial fibrillation increased significantly after completion of th e procedure (p < 0.001). Furthermore, LA stiffness decreased in both g roups. Conclusions. After RNBMV, there is a significant increase in LA pump function in patients with sinus rhythm, a significant increase i n LA reservoir function in patients with atrial fibrillation and a sig nificant reduction in LA stiffness in all patients. Marked alterations of the configuration of the LA pressure-area relation occur immediate ly. (C) 1998 by the American College of Cardiology.