Left ventricular false tendons: echocardiographic incidence in India and clinical importance

Cardiac ventricular false tendons: A meta-analysis

Ventricular false tendons are fibromuscular structures that travel across the ventricular cavity. Left ventricular false tendons (LVFTs) have been examined through gross dissection and echocardiography. This study aimed to comprehensively evaluate the prevalence, morphology, and clinical importance of ventricular false tendons using a systematic review. In multiple studies, these structures have had a wide reported prevalence ranging from less than 1% to 100% of cases. This meta-analysis found the overall pooled prevalence of LVFTs to be 30.2%. Subgroup analysis indicated the prevalence to be 55.1% in cadaveric studies and 24.5% in living patients predominantly studied by echocardiography. Morphologically, left and right ventricular false tendons have been classified into several types based on their location and attachments. Studies have demonstrated false tendons have important clinical implications involving innocent murmurs, premature ventricular contractions, early repolarization, and impairment of systolic and diastolic function. Despite these potential complications, there is evidence demonstrating that the presence of false tendons can lead to positive clinical outcomes.

Three-dimensional echocardiographic assessment of Chiari’s network relationship with the left ventricular false tendon

Background

Left ventricular false tendon (LVFT) is a fibromuscular band crossing the left ventricular cavity. And Chiari’s network (CN) is a highly mobile, mesh-like, echogenic structure in right atrium. In this study, we aimed to evaluate the coexistence of LVFT in patients with CN. CN patients were examined with live/real-time three-dimensional transthoracic echocardiography (TTE) for visualization of LVFT.

Results

This is a single-center prospective study of 49 patients with CN. In literature studies, the average ratios of LVFT were 22% in the normal population. In our study, an increased ratio of LVFT (n = 31, 63.3%) was found in CN patients evaluated with a three-dimensional TTE (63.3% versus 22%) (p = 0.01). The interatrial septal aneurysm was found in 31 (63.3%) patients with CN. And, the positive contrast echocardiography examination was determined in 22 (61.1%) patients with CN.

Conclusions

Our study reveals that CN is associated with LVFT and is also associated with cardiac anomalies like an interatrial septal aneurysm, and atrial septal defect. And LVFT can be evaluated better with three-dimensional TTE than with traditional two-dimensional TTE. Patients with CN should be evaluated more carefully by three-dimensional echocardiography as they can be in synergy in terms of the cardiac pathologies they accompany.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43044-022-00287-5.

Protective Role of False Tendon in Subjects with Left Bundle Branch Block: A Virtual Population Study

False tendons (FTs) are fibrous or fibromuscular bands that can be found in both the normal and abnormal human heart in various anatomical forms depending on their attachment points, tissue types, and geometrical properties. While FTs are widely considered to affect the function of the heart, their specific roles remain largely unclear and unexplored. In this paper, we present an in silico study of the ventricular activation time of the human heart in the presence of FTs. This study presents the first computational model of the human heart that includes a FT, Purkinje network, and papillary muscles. Based on this model, we perform simulations to investigate the effect of different types of FTs on hearts with the electrical conduction abnormality of a left bundle branch block (LBBB). We employ a virtual population of 70 human hearts derived from a statistical atlas, and run a total of 560 simulations to assess ventricular activation time with different FT configurations. The obtained results indicate that, in the presence of a LBBB, the FT reduces the total activation time that is abnormally augmented due to a branch block, to such an extent that surgical implant of cardiac resynchronisation devices might not be recommended by international guidelines. Specifically, the simulation results show that FTs reduce the QRS duration at least 10 ms in 80% of hearts, and up to 45 ms for FTs connecting to the ventricular free wall, suggesting a significant reduction of cardiovascular mortality risk. In further simulation studies we show the reduction in the QRS duration is more sensitive to the shape of the heart then the size of the heart or the exact location of the FT. Finally, the model suggests that FTs may contribute to reducing the activation time difference between the left and right ventricles from 12 ms to 4 ms. We conclude that FTs may provide an alternative conduction pathway that compensates for the propagation delay caused by the LBBB. Further investigation is needed to quantify the clinical impact of FTs on cardiovascular mortality risk.

Basic Study and Clinical Implications of Left Ventricular False Tendon. Is it Associated With Innocent Murmur in Children or Heart Disease?

INTRODUCTION AND OBJECTIVES

Left ventricular false tendon is a structure of unknown function in cardiac physiology that was first described anatomically by Turner. This condition may be related to various electrical or functional abnormalities, but no consensus has ever been reached. The purpose of this study was to determine the time of appearance, prevalence and histologic composition of false tendon, as well as its association with innocent murmur in children and with heart disease.

METHODS

The basic research was performed by anatomic dissection of hearts from adult human cadavers to describe false tendon and its histology. The clinical research consisted of echocardiographic study in a pediatric population to identify any relationship with heart disease, innocent murmur in children, or other abnormalities. Fetal echocardiography was performed prenatally at different gestational ages.

RESULTS

False tendon was a normal finding in cardiac dissection and was composed of muscle and connective tissue fibers. In the pediatric population, false tendon was present in 83% on echocardiography and showed a statistically significant association only with innocent murmur in children and slower aortic acceleration. The presence of false tendon was first observed on fetal echocardiography from week 20 of pregnancy.

CONCLUSIONS

Left ventricular false tendon is a normal finding visualized by fetal echocardiography from week 20 and is present until adulthood with no pathologic effects except for innocent murmur during childhood. It remains to be determined if false tendon is the cause of the murmurs or if its absence or structural anomalies are related to disease.

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.

False tendons: an endoscopic cadaveric approach

False tendons (FTs) have been extensively described and recognized by gross anatomic studies. However, in the clinical setting the recognition of FTs is limited to the use of echocardiography. We examined 200 formalin fixed adult hearts, with gross dissections. In addition, 90 of these specimens were also examined with ultrasonographic and endoscopic techniques. Gross examination was able to identify FTs in 128 (62%) specimens. The total number of FTs observed, was 248 and was classified into five types according to their location. In Type I (92, 37.1%) the FT was located between the posteromedial papillary muscle and the ventricular septum. In Type II (55, 22.1%) the FT was located between the two papillary muscles. Type III (41, 16.5%) was classified as an FT between the anterolateral papillary muscle and the ventricular septum. The FT in Type IV (31, 12.5%) was observed to connect between the ventricular septum and the free wall and lastly in Type V (29, 11.6%) the FTs were found to be weblike with three or more points of insertion. When using all three techniques (n = 90), gross dissection and endoscopy were able to identify FTs in 62.2% of specimens while echocardiographic imaging was only able to identify FTs in 27.7% of specimens. Of the 114 FTs detected grossly and endoscopically, echocardiography was only able to identify 46 (40.3%). Therefore, the overall sensitivity of echocardiography for detecting left ventricular FTs was only 40.3%, compared to 100% for endoscopy. Based upon the ability or lack thereof of echocardiography to detect certain topographical patterns, we have created a small series of subtypes for the FTs. Histologically, in 30% of the FTs, conduction tissue fiber was observed to be present, which may implicate them in the appearance of arrhythmias.

Incidence and distribution of left ventricular false tendons: an autopsy study of 483 normal human hearts

The incidence and distribution of left ventricular false tendons were studied in a series of 483 autopsy specimens of human hearts from subjects evenly distributed by sex and age. False tendons were observed in 265 specimens (55%), and their incidence was greater in hearts from male than from female subjects (61 versus 49%; p less than 0.01). Neither the incidence nor the location of false tendons varied appreciably with age. Of the 265 specimens containing false tendons, 100 (38%) exhibited 2 or more, such that the total number of false tendons identified was 414. Of these 414, 272 (66%) were located between the posteromedial papillary muscle and the ventricular septum, 49 (12%) between the two papillary muscles, 47 (11%) between the anterolateral papillary muscle and the ventricular septum, 38 (9%) between the free wall and the septum and 3 (less than 1%) between two aspects of the free wall; 5 (1%) had three or more points of insertion and formed weblike structures. False tendons are common anatomic variants of the normal human left ventricle which may be detected by two-dimensional echocardiography and should not be misinterpreted as pathologic structures such as flail mitral chordae tendineae or mural thrombi.

Relation of Still's murmur, small aortic diameter and high aortic velocity

The origin of Still's innocent murmur, first described in 1909, is obscure. Seventy normal children and young adults, 29 with Still's murmur and 41 with no murmur, were studied. Pulsed Doppler and 2-dimensional echocardiography were used to evaluate possible causes, including tricuspid regurgitation, left ventricular bands, ascending and descending aortic and pulmonary velocities, ascending aortic diameter, and magnitude of spectral widths. Mean ascending aortic diameter relative to body surface area was significantly smaller for the group with Still's murmur (p less than 0.001). Since cardiac output was similar for the 2 groups, the average peak ascending velocity (133 cm/s) and average peak descending aortic velocity (118 cm/s) were significantly higher in the innocent murmur group as compared to similar respective means in the control group without the murmur (107 and 104 cm/s, respectively) (p less than 0.001 and p less than 0.01, respectively). No significant differences were found when the 2 groups were compared with respect to mean peak pulmonary artery velocity adjusted for body size, spectral widths in the ascending and descending aorta and in the pulmonary artery, and the presence of tricuspid regurgitation or ventricular bands. These observations suggest that the origin of Still's murmur is related to a small ascending aortic diameter with concomitant high aortic blood flow velocity.

A reappraisal of the prevalence and clinical importance of left ventricular false tendons in children and adults

The prevalence and clinical importance of false tendons were studied in 488 consecutive patients referred for echocardiography. Two hundred and eighty three (58%) patients had acquired heart disease, 91 (19%) had congenital heart disease, and 114 (23%) had normal hearts. Sixty six patients with normal hearts had innocent systolic murmurs and one had recurrent ventricular tachycardia. The overall prevalence of false tendons was 25% compared with 1.6% in a retrospective analysis of 763 cross sectional echocardiograms. When patients with innocent murmurs were excluded from statistical analysis, there was no significant difference in the prevalence of these tendons between children and adults, boys and girls, men and women, or between patients with acquired or congenital heart disease and normal patients. The prevalence of false tendons in patients with dilated left ventricles (57%), however, resembled that seen in necropsy studies. The prevalence of false tendons in patients with an innocent systolic murmur was 76% in children and 40% in adults, with an overall prevalence of 52%. False tendons are a common echocardiographic finding of no clinical importance except for their possible role in the genesis of innocent murmurs and ventricular arrhythmias. The echocardiographic detection of false tendons increases considerably when these structures are specifically sought and in conditions that result in left ventricular chamber dilatation.