Evidence of Atrial Functional Mitral Regurgitation Due to Atrial Fibrillation

The purpose of this study was to determine whether atrial fibrillation (AF) might cause significant mitral regurgitation (MR), and to see whether this MR improves with restoration of sinus rhythm. MR can be classified by leaflet pathology (organic/primary and functional/secondary) and by leaflet motion (normal, excessive, restrictive). The existence of secondary, normal leaflet motion MR remains controversial. We performed a retrospective cohort study. Patients undergoing first AF ablation at our institution (n = 828) were screened. Included patients had echocardiograms at the time of ablation and at 1-year clinical follow-up. The MR cohort (n = 53) had at least moderate MR. A reference cohort (n = 53) was randomly selected from those patients (n = 660) with mild or less MR. Baseline echocardiographic and clinical characteristics were compared, and the effect of restoration of sinus rhythm was assessed by follow-up echocardiograms. MR patients were older than controls and more often had persistent AF (62% vs. 23%, p < 0.0001). MR patients had larger left atria (volume index: 32 cm3/m2 vs. 26 cm3/m2, p = 0.008) and annular size (3.49 cm vs. 3.23 cm, p = 0.001), but similar left ventricular size and ejection fraction. Annular size, age and persistent AF were independently associated with MR. On follow-up echocardiogram, patients in continuous sinus rhythm had greater reductions in left atrial size and annular dimension, and lower rates of significant MR (24% vs. 82%, p = 0.005) compared with those in whom sinus rhythm was not restored. AF can result in “atrial functional MR” that improves if sinus rhythm is restored.