Dynamic Piston Function of the Mitral Annulus to Assess Early Left Ventricular Diastolic Filling: A Proof of Concept Study

Abstract

Introduction: Early left ventricular (LV) filling has been described as an asymmetric toroidal vortex ring of blood entering the LV upon opening of the mitral valve. This phenomenon is in part responsible for cyclical changes in LV volumes during the cardiac cycle and also contributes to the apical and basal longitudinal displacements of the mitral annulus (MA). Although MA early diastolic (e’) velocities have been used to assess early LV filling characteristics, accurate distinction between normal aging and pathological diastolic dysfunction (DD) might be challenging at times. Methods: In this pilot study, echocardiographic data from 60 consecutive patients were reviewed. The studied population was allocated into three groups based on the new American Society of Echocardiography guidelines for diastolic dysfunction classification. To better define LVDD, we based our interpretation of MA tissue Doppler imaging (TDI) signals on the well-described displacement pump mechanism of the MA plane functioning as a piston unit. Results: Patients with normal diastolic function were younger (50 ± 14 years) than those with DD (group II: 69 ± 8 and group III: 63 ± 17 years) (p < 0.001) with a slight female predominance (57%). As expected, volumetric variables as well as mitral inflow and MA TDI measures were significantly different among the three studied groups (p < 0.001) with the exception of the left atrial volume index. Interestingly, careful interrogation of the MA TDI signal revealed a distinctive appearance of a recoil signal right after the MA e’ velocity only occurring in patients with normal LV diastolic function. Conclusions: Identification of an early characteristic recoil signal occurring on the MA TDI right after the e’ velocity seems to be useful in the characterization of LVDD. Additional prospective studies are now needed to validate its utility as an additional criterion to be used in LVDD.