Echocardiographic description of mitral annular disjunction in mitral valve prolapse and implication in arrhythmic risk stratification

Abstract

Mitral annular disjunction (MAD) is an anatomical variation of the mitral annulus, characterized by an atrial displacement of the leaflet's hinge points. It is associated with severe ventricular arrhythmias (VA) in mitral valve prolapse (MVP). The aim of this study was to assess MAD in MVP by echocardiography, analyze the reproducibility of measurements and evaluate its importance for arrhythmic risk stratification along with strain analysis of myocardial deformation. Two hundred and sixty patients with MVP were included. MAD was evaluated and measured by two observers and longitudinal strain was analyzed by speckle-tracking. In total, 36.2% of MVP patients had MAD and were younger (P = 0.033) with higher rate of atypical chest pains (P = 0.041) and bileaflet prolapses (P = 0.004). Para-sternal long-axis view was the incidence of choice to detect MAD with a moderate inter-observer concordance (Kappa of 0.55), good correlation (r = 0.69, P < 0.01) and inter-class correlation coefficient (0.82; 0.67–0.90). Twenty patients had a history of severe VA. Among them, no difference was noted in terms of presence or severity of MAD. However, strain analysis showed reduced global longitudinal strain (18.6 ± 3.1 vs. 21.3 ± 3.3%, P = 0.001) and higher mechanical dispersion values (46 ± 13 vs. 37.4 ± 12.9 ms, P = 0.002) in comparison to the rest of the MVP population. No significant association was found between severe VA and the presence or severity of MAD in MVP patients. Increased mechanical dispersion and reduced global longitudinal strain may be helpful for arrhythmic risk stratification. Comparison of severe ventricular arrhythmias (Fig. 1).