To evaluate the risk determinants of atrial fibrillation using cardiac MRI based parameters in patients with rheumatic mitral valve disease (RF_TH_215)

Rheumatic heart disease (RHD) is the most common valvular heart disease in developing countries. Patients of RHD are often complicated with atrial fibrillation (AF). The present study sought to identify the risk determinants of atrial fibrillation using cardiac MRI based parameters of structural remodeling and tissue characteristics. We also aimed to evaluate atrial fibrosis on DE-MRI (delayed enhanced MRI) with respect to its amount, distribution and its association with atrial fibrillation. 

Methods:

This was a tertiary care hospital based prospective case control study. A CMR based assessment of atrial and ventricular structural remodelling and tissue characterization was done in sixty consecutive patients (thirty patients each with and without documented atrial fibrillation) with moderate to severe rheumatic mitral valve disease.  We divided LA into anterior wall, posterior wall and septum. LA fibrosis was classified as mild, moderate and severe on DE-MRI. The association of clinical and MRI parameters with atrial fibrillation was estimated by calculating Odds ratio with 95% C.I. using multivariate logistic regression model.

Results: In our study, the median LVEF of the 60 patients was 50.35% and RVEF was 42%. The presence of tricuspid regurgitation, LA diameter, LA volume, LVEF and RVEF were significantly higher in patients with atrial fibrillation compared to group without atrial fibrillation. LA posterior wall fibrosis was the most common followed by interatrial septum and anterior wall. The proportion of patients with LA fibrosis was significantly higher in group with atrial fibrillation (28 vs. 8;  p< 0.001).  The severity of fibrosis was also significantly higher in patients in atrial fibrillation group.LA fibrosis was independent predictor of atrial fibrillation (Odd’s ratio: 25.9, 95% CI; p < 0.001) on multivariate regression analysis.

Conclusion:

CMR based assessment of LA fibrosis could be used as the risk prediction tool in identifying patients of rheumatic mitral valve disease in normal sinus rhythm at risk of developing atrial fibrillation and for tracking disease progression.