Mitral regurgitation: not a single disease with systematic and identic functional and haemodynamic consequences

This editorial refers to ‘Prevalence, distribution, and determinants of pulmonary venous systolic flow reversal in severe mitral regurgitation’ by K.U. Itakura et al., pp. 964--73. The understanding of mitral regurgitation (MR) has tremendously changed over the past years thanks to new percutaneous treatments requiring an accurate quantification and rigorous monitoring by echocardiography and by the development of other imaging techniques.1,2 Itakura et al.3 examined the association between MR mechanism and the flow pattern of pulmonary veins. This is a unique descriptive study including 125 patients with severe MR. The authors were able to analyse flows in all four pulmonary veins in 96.8% of the population by using transoesophageal echocardiography (TOE). Patients were not all referred for a percutaneous management but they made an effort to compile several interesting data including clinical, invasive haemodynamic, and echocardiographic information. Itakura et al.3 reported that only...