Elevated left atrial pressure estimated by Doppler echocardiography is a key determinant of mitral valve tenting in functional mitral regurgitation.

Background: Functional mitral regurgitation (FMR) may occur in patients with reduced or preserved left ventricular ejection fraction (LVEF) and has been associated with excess valvular tenting only in patients with reduced LVEF. This study aimed at identifying the predictors of FMR and to determine whether or not they are different in patients with reduced versus preserved LVEF.

Methods: 190 consecutive patients free of congenital or primary valvular disease had a comprehensive echocardiographic assessment of LV remodelling and function, diastolic function and FMR severity.

Results: 112 patients had depressed LVEF (<50%) and 78 had preserved LVEF. FMR was present in 30 patients with preserved LVEF and in 65 with reduced LVEF. Higher E/Ea, E/A and larger mitral tenting were independent predictors of FMR regardless of LVEF. The mitral tenting area was an independent predictor of FMR severity in patients with reduced or preserved LVEF (p = 0.04 and p = 0.0045) in addition to E/A (p = 0.0007), E/Ea (p = 0.004) in patients with reduced and preserved LVEF, respectively. Higher E/Ea was independently associated with larger mitral tenting in patients with reduced and preserved LVEF. Mitral tenting area was linearly related to E/Ea (r = 0.30, p<0.0001) and E/A (r = 0.43, p<0.0001) and LA enlargement (r = 0.54, p<0.0001) after having paired 96 patients with and without FMR on indices of LV remodelling.

Conclusions: In both patients with preserved and reduced LVEF, mitral tenting that leads to FMR is mainly determined by both mitral tethering forces-that is, displacement of papillary muscles and by pushing forces-that is, increased left atrial pressure. This study underscores that LV preload is a key determinant of FMR.