Left atrium volume index and pathological features of left atrial appendage as a predictor of failure in postoperative sinus conversion.

ABSTRACT

BACKGROUND: Previous studies showed that some parameters, including left atrium diameter and left atrium volume index (LAVI), predicted the success of sinus conversion. However, no previous studies have investigated the association of sinus conversion with LAVI and histopathological findings. This study was designed to investigate the relationship among LAVI, pathological assessment, and failure in sinus conversion after surgery for valvular atrial fibrillation (AF). METHODS AND RESULTS: A total of 78 patients with left atrium enlargement and valvular AF who underwent maze procedure concomitantly with various cardiac surgeries were classified into one of two groups those who successfully underwent sinus conversion (Group 1; n=40) and those who did not achieve sinus conversion (Group 2; n=38). Histopathological assessment was performed in 9 cases using tissues derived from the left atrial appendage (LAA). The degree of histopathological change was classified into 1 of 4 grades. LAVI was significantly less in Group 1 than in Group 2 (81 + or - 22 ml/m(2) vs. 122 + or - 49 ml/m(2), p<0.001). Preoperative LAVI predicted 100% failure of sinus conversion after surgery with a cut-off value of 135 ml/m(2). Histopathological analyses clearly showed that the grades for intercellular fibrosis, fatty infiltration, endocardial thickening, and nuclear enlargement/abnormalities were significantly and positively correlated with LAVI (r=0.75, p<0.05; r=0.74, p<0.05; r=0.69, p<0.05; r=0.77, p<0.05, respectively). CONCLUSIONS: LAVI associated with histopathological features of the resected LAA is a predictor of failure in sinus conversion following surgical intervention in patients with valvular AF.