Left ventricular false tendons: echocardiographic, morphologic, and histopathologic studies and review of the literature.

Background: Left ventricular false tendons (LVFTs) are fibrous or fibromuscular bands stretching across the left ventricle (LV) from the ventricular septum to the papillary muscle or LV free wall but not connecting, like the chordae tendinae, to the mitral leaflet. LVFTs have become the focus of studies and discussions since the advent of echocardiography.

Materials And Methods: We prospectively studied the prevalence of LVFTs by two-dimensional echocardiography in 476 infants and children referred to our institute for cardiac evaluation and cardiology workup. We also studied the morphology and histopathology of LVFTs in 68 congenital heart disease specimens and in 20 piglet hearts. The literature was reviewed and the clinical significance of LVFTs was discussed.

Results: LVFTs of varying size and different location were detected in 371 (77.9%) of 476 infants and children studied, in 42 (61.8%) of 68 congenital heart disease specimens, and in 19 (95.0%) of 20 piglet hearts. Of the 75 LVFTs from the congenital heart disease specimens, 33 (44.4%) were fibrous type, measuring less than 1.4mm; 38 (50.7%) were fibromuscular type, 1.5-2.4mm; and 4 (5.3%) were muscular type, 2.5mm or more in diameter. Of the 33 LVFTs from the piglet hearts, 23 (69.7%) and 10 (30.3%) were fibrous and fibromuscular, respectively, and none (0.0%) was muscular.

Conclusions: LVFTs were detected partially or completely by modified two-dimensional echocardiography in both normal and abnormal hearts. LVFTs is a useful anatomical landmark of LV for the differentiation of morphological LV and right ventricle in segmental analysis of congenital heart disease. LVFTs are a cause of functional murmur. No pressure gradient was noted in the mid-LV or outflow tract. LVFTs could be a contributory factor in the generation of dysrhythmias during LV catheterization studies. LVFTs were more easily identifiable in neonates and young age patients because of a better delineation of images in echocardiography.