Left atrial function after Coxʹs maze operation concomitant with mitral valve operation

Background. This study examined whether the atrial fibrillation that commonly occurs in patients with a mitral valve operation could be eliminated by a concomitant maze operation. Methods. Left atrial function after Coxʹs maze operation performed concomitantly with a mitral valve operation was evaluated in 10 patients ranging in age from 38 to 67 years (mean age, 54 years). Seven patients who had had coronary artery bypass grafting served as the control group. Using transthoracic echocardiography, the ratio between the peak speed of the early filling wave and that of the atrial contraction wave (A/E ratio) and the atrial filling fraction (AFF) were determined from transmitral flow measurements. These two indices have been considered to represent the contribution of left atrial active contraction to ventricular filling. Results. The A/E ratio and the AFF were significantly lower in the maze group (0.35 ± 0.17 versus 0.97 ± 0.28 [p < 0.01] and 17.6% ± 8.8% versus 36.8% ± 6.4% [p < 0.01], respectively). The A/E ratio and the AFF correlated inversely with age (r = −0.72, p < 0.05 and r = 0.76, p < 0.05, respectively) in the maze group. In an angiographic study, the mean left atrial maximal volume index in the maze group was approximately three times larger than that in the control group (117.5 ± 24.3 mL/m2 versus 35.3 ± 6.6 mL/m2 [p < 0.01]). The left atrial active emptying volume index was significantly smaller in patients in the maze group (7.2 ± 2.5 mL/m2 versus 13.1 ± 4.6 mL/m2 [p < 0.01]). Conclusions. After the maze procedure performed concomitantly with a mitral valve operation in patients with a dilated left atrium, left atrial contraction is detectable but incomplete in the elderly.