The dynamic nature of MR throughout systole and the complexity of MR mechanisms may cause uncertainty among TTE readers and lead to interobserver variability.

To evaluate the interobserver agreement of parameters used in daily practice to quantify mitral regurgitation (MR) severity according to the experience of the physician.

Complete MR evaluation of 25 consecutive patients were assessed by transthoracic echocardiography in 8 French tertiary public and private hospitals by 16 physicians (1 junior and 1 senior in each centre).

In total, 400 analyses per parameter have been obtained. The overall interobserver agreement for effective regurgitant orifice area (EROA) and regurgitant volume (RV) was only moderate, lower in secondary MR. Interobserver agreement was better in the senior group than in the junior group regarding parameters used to quantify MR severity, i.e. EROA, respectively substantial (0.61, 95% CI: 0.45–0.75) and fair (0.33, 95% CI: 0.19–0.51) and RV with the PISA method, respectively moderate (0.50, 95% CI: 0.33–0.56) and fair (0.36, 95% CI: 0.36–0.43). Finally, using a multiparametric approach, the overall interobserver agreement for grading MR severity was fair (0.30), slightly better in the senior group than the junior group (respectively 0.31 vs. 0.28) with a substantial or almost perfect agreement more frequently observed in the senior group than in the junior group (respectively 52% vs. 36%).

The use of quantitative parameters to assess MR severity was moderately reliable in daily practice, even in case of multiparametric approach. The experience of the physician and the mechanism of the MR impact interobserver agreement, paving the way for a better learning of this valvular disease and for the use of multimodality imaging in case of complex or secondary MR.