Myocardial work and left heart deformation parameters across primary mitral regurgitation severity

Myocardial work (MW) estimation by pressure-strain loops using speckle tracking echocardiography (STE) has shown to evaluate left ventricular (LV) contraction overcoming the load-dependency limit of LV global longitudinal strain (GLS). This has proved useful in hemodynamic variation settings e.g. heart failure and valvular heart disease. However, the variation of MW and strain parameters across different stages of primary mitral regurgitation (MR) and its impact on symptoms, which was the aim of our study, has never been investigated.

Consecutive patients with mild, moderate and severe MR were prospectively enrolled. Exclusion criteria were: chronic atrial fibrillation, valvular heart prosthesis, previous cardiac surgery. Clinical evaluation, blood sample tests, ECG and echocardiography with STE and MW measurement were performed. Patients were then divided into groups according to MR severity. Differences among the groups and predictors of symptoms (as NYHA class≥2) were explored as study endpoints. Overall, 180 patients were enrolled (60 mild,60 moderate,60 severe MR). LV GLS and global peak atrial longitudinal strain (PALS) reduced according to MR severity. Global constructive work (GCW) and global wasted work (GWW) significantly improved, while global work efficiency (GWE) reduced, in patients with moderate and severe MR. Among echocardiographic parameters, global PALS emerged as the best predictor of NYHA class (p < 0.001;area under curve,AUC = 0.7).

MW parameters accurately describe the pathophysiology of MR, with initial attempt of LV increased contractility to compensate volume overload parallel to the disease progress, although with low efficacy, while global PALS is the most associated with the burden of MR symptoms.