Abstract 3386: Mechanism Of Mitral Regurgitation In Patients With Idiopathic Dilated Cardiomyopathy: Importance Of Augmented Posterior Mitral Leaflet Tethering With Aberrant Tendinous Chords
Objectives The purpose of this study was to test the determinants of mitral regurgitation (MR) and the effect of aberrant tendinous chords on MR in patients with idiopathic dilated cardiomyopathy (DCM).
Background Left ventricular (LV) dilatation causes mitral leaflet tethering which results in the development of MR. However, the presence of aberrant tendinous chords which arise from posterior wall and adhere to posterior mitral leaflet can influence posterior leaflet tethering and MR.
Methods In consecutive 50 patients with idiopathic DCM, LV volume, LV ejection fraction (EF), left atrial (LA) volume, mitral annular area (MAA), mitral valve tenting area, angle between anterior leaflet and the mitral annular line at leaflet closing (α1), angle between posterior leaflet and mitral annular line (α2), isovolumic relaxation time, LV dyssynchrony and MR fraction were quantified by transthoracic echocardiography. The patients were divided into two groups: group 1 with aberrant tendinous chords and group 2 without them.
Results 1) α2 and MR were significantly increased in group 1 compared with group2. 2) MR fraction was significantly correlated with α2 (r2 = 0.40), mitral valve tenting area (r2 = 0.29), LA volume (r2 = 0.29) and multiple regression analysis identified an increase in α2 as the only independent determinant of MR fraction in group 1. On the other hand, MR fraction was significantly correlated with LV volume (r2 = 0.68), mitral valve tenting area (r2 = 0.60), and MAA (r2 = 0.26) in group 2.
Conclusion Besides the alteration in LV geometry, the presence of aberrant tendinous chord, augmenting posterior leaflet tethering, induces important MR in patients with idiopathic DCM.