LAUSR

From the first landmark trials of transcatheter edge to edge repair (TEER) in the treatment of mitral regurgitation (MR), it has become abundantly clear that one size (or treatment in this case) does not fit all. 1,2 A relatively new classification, atrial functional mitral regurgitation (A ‐ FMR) was well described early on by Dziadzko et al. as a population with notable excess mortality and frequent heart failure despite its normal ejection fraction and low regurgitant volumes. 3 Interventionalists treating MR with TEER should be aware of the different etiologies of MR, in particular the subset of A ‐ FMR described in this issue of CCI by Simard et al. Their report has low patient numbers, making comparisons difficult, and possibly underestimates differences that would be more prominent in a larger study. However, the study supports the different outcomes associated with A ‐ FMR, and investigates how TEER in this population compares to ventricular functional mitral regurgitation (V ‐ FMR). Twenty ‐ one A ‐ FMR patients were compared with thirty ‐ seven V ‐ FMR patients who underwent TEER looking at clinical, hemodynamic, and echocardiographic parameters. With results limited by these small numbers, they found: final MR severity achieved by echocardiography post procedure and at 1 year were similar in both groups; similar patient symptom class improvement at 1 year; amount of clips and technical success of the procedure were comparable. But importantly, left atrial pressures were largely unchanged in the A ‐ FMR group after intervention in compari-son to a drop in the V ‐ FMR group. In addition they found a higher prevalence of TR in the A ‐ FMR group at baseline. Conclusions about if/how