Relationship between Left Atrial Volume Index and Atrial Fibrillation after Mitral Valve Replacement in Patients with Mitral Valve Disease

Background: Mitral valve replacement (MVR) is a surgical procedure that is often performed in patients with severe mitral valve disease, to replace the damaged valve with a new artificial valve. Left Atrial Volume Index (LAVI) is a measurement of the size of the left atrium of the heart, normalized to the body surface area which is often used as an indicator of left atrial enlargement, which is a common finding in patients with mitral valve disease. There is a significant relationship between LAVI and Atrial Fibrillation (AF) after MVR in patients with mitral valve disease. Aim of the study: The aim of this study was to evaluate the relationship between LAVI and the occurrence of atrial fibrillation after mitral valve replacement in patients with mitral valve diseases. Methods: This prospective observational study was conducted in the department of Cardiac Surgery, National Institute of Cardiovascular Diseases (NICVD), Dhaka from March, 2018 to February, 2019. Total 60 patients were divided into two groups, out of them 30 patients had LAVI e”39 ml/m² (Group-A) and 30 patients had LAVI d” 39ml/m² (Group-B). Result: In patients with post-operative AF after MVR, was evaluated by ECG in the presence or absence of pwave and irregular R-R interval and measurement of LAVI more or less than cutoff value 39 ml/m². On postoperative day 3, 7 (23.33%) patients in Group A and 02(6.66%) patients in Group B developed post-operative AF. In Group A there was reduction in the LAVI but not below the cutoff value whereas in Group B, the LAVI was reduced below the cutoff value (< 39 ml/m2). On overall evaluation, after mitral valve replacement increased LAVI is significantly associated with post-operative AF occurrence and is a better predictor than LA diameters. From univariate analysis in our cohort, high inotropes support, MVT, ACT, CPB time and postoperative LAVI were significantly associated with occurrence of AF. But multiple logistic regression analysis revealed postoperative LAVI to be only significant predictor of occurrence of AF after Mitral valve replacement. Conclusion: Our study shows that postoperative LAVI measured by 2-D echocardiography is positively and independently associated with the occurrence of postoperative AF following MVR. Moreover, clinical risk factors are fairly good predictors of the occurrence of AF after MVR, but postoperative LAVI was the most significant independent predictor of postoperative AF in our study. Bangladesh Heart Journal 2023; 38(1): 38-45