Effects and mechanisms of left ventricular false tendons on functional mitral regurgitation in patients with severe cardiomyopathy

Abstract

False tendons in the left ventricle are commonly observed. Preliminary observations associate false tendons with less functional mitral regurgitation. Echocardiograms demonstrating severe cardiomyopathy (ejection fraction < or =30%) were retrospectively examined for left ventricular false tendons. The ejection fraction, cause of left ventricular systolic dysfunction, left ventricular diastolic dimensions, severity of mitral regurgitation, mitral annular diameter, mitral valve coaptation depth, mitral valve coaptation area, and orientation of false tendon were evaluated. The patients with false tendons were compared with a control group with cardiomyopathy without false tendons. A cohort of patients (n = 82) with severe left ventricular systolic dysfunction (mean ejection fraction, 21%) and false tendons were compared with a control group with similar left ventricular dysfunction and no false tendons (n = 121; mean ejection fraction, 20%; P = .10). The patients with false tendons had similar left ventricular diastolic internal dimensions compared with the control group (5.99 and 6.18 cm, respectively; P = .086). Yet patients with false tendons had a very low incidence of severe functional mitral regurgitation compared with the control group (4.9% vs 27%, P < .001). Patients with false tendons had significantly smaller mitral annular diameters (3.57 vs 4.03 cm, P < .001), shorter mitral valve coaptation depths (0.89 vs 1.24 cm, P < .001), and reduced coaptation areas (1.61 vs 2.52 cm(2), P < .001) than the control group. The reduction of mitral regurgitation was more significant for patient with transverse midcavity false tendons. Patients with false tendons and cardiomyopathy have less severe mitral regurgitation. The mechanism for the reduction in functional mitral regurgitation might be less mitral valve deformation, specifically lower coaptation depth and coaptation area when a false tendon is present.