Search

Simple Summary: Understanding the precise anatomy of the left and right subvalvular apparatus in the domestic horse can contribute to the development of normal and comparative animal anatomy, as well as surgery, internal medicine, and biology. This study conducts such an analysis, taking into account the thickness of the left ventricular wall, the right ventricular wall, the interventricular septum, the ventricle's length, and the entire heart's width. Additionally, it examines the number of muscle bellies of the papillary muscles, the type of connection between the muscle and the heart wall, the height of muscle origin, and the length of the papillary muscle. This study calculates various proportions and compares them with descriptions of subvalvular apparatuses in other animal species, including humans, available in the literature. Due to the growing interest among veterinarians and the increasing market demands, the development of equine cardiology is necessary. Currently, veterinary medicine for companion animals needs to catch up to human medicine—equine medicine included. A common condition in older horses is aortic valve regurgitation resulting from fibrosis, while its more severe form occurs in younger horses or develops due to a bacterial infection. Mitral valve regurgitation, especially dangerous due to the possibility of sudden death, has a better prognosis if the horse has valve prolapse. Tricuspid valve regurgitation usually does not pose a clinical problem, although its severe cases may lead to heart failure. Some pathologies can be treated surgically, which requires excellent knowledge of anatomy. The object of this study consisted of twenty domestic horse hearts. The focus was on the normal and comparative anatomy of the left and right subvalvular apparatus. The number of muscular bellies of the papillary muscles and the type of connection of the muscles were analysed. Moreover, the height of muscle originating from the ventricle wall was determined, the morphological regularity of the papillary muscle was assessed, and the chordae tendineae originating from the papillary muscles were examined. The conducted research allowed for comparing domestic horses with different species through other studies, the authors of which described this particular aspect. Interspecies similarities which may be correlated with the evolutionary relatedness, as well as differences that could reflect adaptation to different lifestyles, environmental conditions, or metabolic requirements of the animals, have been found. This study expands the knowledge of animals' normal and comparative anatomy, and contributes to the development of veterinary surgery, internal medicine, and biology. [ABSTRACT FROM AUTHOR]

Precise appreciation of the 3-dimensional relationship between the edge-to-edge clips and mitral valve apparatus remains clinically challenging. We demonstrate the images of clips observed in situ 4 years after implantation. Detailed observation from this case helps improve our understanding of 3-dimensional clinical cardiac anatomy related to transcatheter edge-to-edge mitral valve repair. (Level of Difficulty: Intermediate.).

The chordae tendineae, described as fibro-collagenous structures, support the leaflets of the atrioventricular valves of the heart in various ways. The chordae tendineae are composed of collagen and elastic fibers. They connect to the ventricular side of the valve leaflets' free border and hinder the leaflets from swinging back into the atrial cavity during systole. Mitral valve chordae tendineae have been classified using a variety of classification systems. To our knowledge, we report a variant chordae tendinea that has yet to be described in the literature. The variant, present only on the mitral anterior papillary muscle, did not show the characteristic appearance of the chorda tendineae. Muscular fibers were observed extending from a larger than usual mitral anterior papillary muscle, inserting into the rough zone of the anterior leaflet. Several tendinous primary and secondary true leaflet chordae emerge from the apical portion of the anterior papillary muscle, inserting into the anterior leaflet's free edge and rough zone. Contraction of this muscular chorda during systole could disrupt the mechanics of valvular closure and result in possible regurgitation across the mitral valve. Additionally, this structure may be subject to rupture during myocardial infarction, leading to valvular dysfunction. The developmental connection between the chordae and papillary muscles could explain the anomalous muscularization of the chordae tendineae observed in this case. [ABSTRACT FROM AUTHOR]

Chordae tendineae, referred to as heart tendinous cords, act as tendons connecting the papillary muscles to the valves in the heart. Their role is analogous to tendons in the musculoskeletal system. Despite being exposed to millions of cyclic tensile stretches over a human's lifetime, chordae tendineae rarely suffer from overuse injuries. On the other hand, musculoskeletal tendinopathy is very common and remains challenging in clinical treatment. The objective of this study was to investigate the mechanism behind the remarkable durability and resistance to overuse injuries of chordae tendineae, as well as to explore their effects on flexor tenocyte biology. The messenger RNA expression profiles of chordae tendineae were analyzed using RNA sequencing and verified by quantitative reverse transcription polymerase chain reaction and immunohistochemistry. Interestingly, we found that periostin (Postn) and fibroblast growth factor 7 (FGF7) were expressed at significantly higher levels in chordae tendineae, compared to flexor tendons. We further treated flexor tenocytes in vitro with periostin and FGF7 to examine their effects on the proliferation, migration, apoptosis, and tendon‐related gene expression of flexor tenocytes. The results displayed enhanced cell proliferation ability at an early stage and an antiapoptotic effect on tenocytes, while treated with periostin and/or FGF7 proteins. Furthermore, there was a trend of promoted tenocyte migration capability. These findings indicated that Postn and FGF7 may represent novel cytokines to target flexor tendon healing. Clinical significance: The preliminary discovery leads to a novel idea for treating tendinopathy in the musculoskeletal system using specific molecules identified from chordae tendineae. [ABSTRACT FROM AUTHOR]

Introduction: The anatomically correct chordae tendineae originate from the apical part of the papillary muscles of the ventricles and attach to the corresponding free margins of the atrioventricular valves. Together with the papillary muscles, they contribute to the effective contraction of the ventricles, creating the so-called "annular-ventricular continuity". Aim of the research: This publication aimed to evaluate and analyse the impact of chordae tendineae pathology of the atrioventricular valves on the clinical presentation of a patient. Material and methods: A systematic review of the literature was performed in the PubMed, Web of Science, and Scopus databases and according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Results and conclusions: This review allowed us to distinguish 6 groups of characteristic pathological lesions of chordae tendineae such as thickening, elongation, shortening, fibrosis, complete absence, or histopathological changes of the chordae tendineae. Most of the cases resulted from congenital underlying diseases, and treatment mainly consisted of surgical correction.. [ABSTRACT FROM AUTHOR]

Due to the growing interest among veterinarians and the increasing market demands, the development of equine cardiology is necessary. Currently, veterinary medicine for companion animals needs to catch up to human medicine—equine medicine included. A common condition in older horses is aortic valve regurgitation resulting from fibrosis, while its more severe form occurs in younger horses or develops due to a bacterial infection. Mitral valve regurgitation, especially dangerous due to the possibility of sudden death, has a better prognosis if the horse has valve prolapse. Tricuspid valve regurgitation usually does not pose a clinical problem, although its severe cases may lead to heart failure. Some pathologies can be treated surgically, which requires excellent knowledge of anatomy. The object of this study consisted of twenty domestic horse hearts. The focus was on the normal and comparative anatomy of the left and right subvalvular apparatus. The number of muscular bellies of the papillary muscles and the type of connection of the muscles were analysed. Moreover, the height of muscle originating from the ventricle wall was determined, the morphological regularity of the papillary muscle was assessed, and the chordae tendineae originating from the papillary muscles were examined. The conducted research allowed for comparing domestic horses with different species through other studies, the authors of which described this particular aspect. Interspecies similarities which may be correlated with the evolutionary relatedness, as well as differences that could reflect adaptation to different lifestyles, environmental conditions, or metabolic requirements of the animals, have been found. This study expands the knowledge of animals’ normal and comparative anatomy, and contributes to the development of veterinary surgery, internal medicine, and biology.

Atrioventricular heart valves (AHVs) regulate the unidirectional flow of blood through the heart by opening and closing of the leaflets, which are supported in their functions by the chordae tendineae (CT). The leaflets and CT are primarily composed of collagen fibers that act as the load-bearing component of the tissue microstructures. At the CT-leaflet insertion, the collagen fiber architecture is complex, and has been of increasing focus in the previous literature. However, these previous studies have not been able to quantify the load-dependent changes in the tissues collagen fiber orientations and alignments. In the present study, we address this gap in knowledge by quantifying the changes in the collagen fiber architecture of the mitral and tricuspid valves strut CT-leaflet insertions in response to the applied loads by using a unique approach, which combines polarized spatial frequency domain imaging with uniaxial mechanical testing. Additionally, we characterized these microstructural changes across the same specimen without the need for tissue fixatives. We observed increases in the collagen fiber alignments in the CT-leaflet insertion with increased loading, as described through the degree of optical anisotropy. Furthermore, we used a leaflet-CT-papillary muscle entity method during uniaxial testing to quantify the chordae tendineae mechanics, including the derivation of the Ogden-type constitutive modeling parameters. The results from this study provide a valuable insight into the load-dependent behaviors of the strut CT-leaflet insertion, offering a research avenue to better understand the relationship between tissue mechanics and the microstructure, which will contribute to a deeper understanding of AHV biomechanics.

Precise appreciation of the 3-dimensional relationship between the edge-to-edge clips and mitral valve apparatus remains clinically challenging. We demonstrate the images of clips observed in situ 4 years after implantation. Detailed observation from this case helps improve our understanding of 3-dimensional clinical cardiac anatomy related to transcatheter edge-to-edge mitral valve repair. (Level of Difficulty: Intermediate.)

Current clinical assessment of functional tricuspid valve regurgitation relies on metrics quantified from medical imaging modalities. Although these clinical methodologies are generally successful, the lack of detailed information about the mechanical environment of the valve presents inherent challenges for assessing tricuspid valve regurgitation. In the present study, we have developed a finite element-based in silico model of one porcine tricuspid valve (TV) geometry to investigate how various pathological conditions affect the overall biomechanical function of the TV. There were three primary observations from our results. Firstly, the results of the papillary muscle (PM) displacement study scenario indicated more pronounced changes in the TV biomechanical function. Secondly, compared to uniform annulus dilation, nonuniform dilation scenario induced more evident changes in the von Mises stresses (83.8-125.3 kPa vs 65.1-84.0 kPa) and the Green-Lagrange strains (0.52-0.58 vs 0.47-0.53) for the three TV leaflets. Finally, results from the pulmonary hypertension study scenario showed opposite trends compared to the PM displacement and annulus dilation scenarios. Furthermore, various chordae rupture scenarios were simulated, and the results showed that the chordae tendineae attached to the TV anterior and septal leaflets may be more critical to proper TV function. This in silico modeling-based study has provided a deeper insight into the tricuspid valve pathologies that may be useful, with moderate extensions, for guiding clinical decisions. NOVELTY STATEMENT: The novelties of the research are summarized below: A comprehensive in silico pilot study of how isolated functional tricuspid regurgitation pathologies and ruptured chordae tendineae would alter the tricuspid valve function; An extensive analysis of the tricuspid valve function, including mechanical quantities (eg, the von Mises stress and the Green-Lagrange strain) and clinically-relevant geometry metrics (eg, the tenting area and the coaptation height); and A developed computational modeling pipeline that can be extended to evaluate patient-specific tricuspid valve geometries and enhance the current clinical diagnosis and treatment of tricuspid regurgitation.

Proper blood flow through the atrioventricular heart valves (AHVs) relies on the holistic function of the valve and subvalvular structures, and a failure of any component can lead to life-threatening heart disease. A comprehension of the mechanical characteristics of healthy valvular components is necessary for the refinement of heart valve computational models. In previous studies, the chordae tendineae have been mechanically characterized as individual structures, usually in a clamping-based approach, which may not accurately reflect the in vivo chordal interactions with the leaflet insertion and papillary muscles. In this study, we performed uniaxial mechanical testing of strut chordae tendineae of the AHVs under a unique tine-based leaflet-chordae-papillary muscle testing to observe the chordae mechanics while preserving the subvalvular component interactions. Results of this study provided insight to the disparity of chordae tissue stress-stretch responses between the mitral valve (MV) and the tricuspid valve (TV) under their respective emulated physiological loading. Specifically, strut chordae tendineae of the MV anterior leaflet had peak stretches of 1.09-1.16, while peak stretches of 1.08-1.11 were found for the TV anterior leaflet strut chordae. Constitutive parameters were also derived for the chordae tissue specimens using an Ogden model, which is useful for AHV computational model refinement. Results of this study are beneficial to the eventual improvement of treatment methods for valvular disease.

Mitral valve (MV) tissue engineering is still in its early stage, and one major challenge in MV tissue engineering is to identify appropriate scaffold materials. With the potential of acellular MV scaffolds being demonstrated recently, it is important to have a full understanding of the biomechanics of the native MV components and their acellular scaffolds. In this study, we have successfully characterized the structural and mechanical properties of porcine MV components, including anterior leaflet (AL), posterior leaflet (PL), strut chordae, and basal chordae, before and after decellularization. Quantitative DNA assay showed more than 90% reduction in DNA content, and Griffonia simplicifolia (GS) lectin immunohistochemistry confirmed the complete lack of porcine α-Gal antigen in the acellular MV components. In the acellular AL and PL, the atrialis, spongiosa, and fibrosa trilayered structure, along with its ECM constitutes, i.e., collagen fibers, elastin fibers, and portion of GAGs, were preserved. Nevertheless, the ECM of both AL and PL experienced a certain degree of disruption, exhibiting a less dense, porous ECM morphology. The overall anatomical morphology of the strut and basal chordae were also maintained after decellularization, with longitudinal morphology experiencing minimum disruption, but the cross-sectional morphology exhibiting evenly-distributed porous structure. In the acellular AL and PL, the nonlinear anisotropic biaxial mechanical behavior was overall preserved; however, uniaxial tensile tests showed that the removal of cellular content and the disruption of structural ECM did result in small decreases in maximum tensile modulus, tissue extensibility, failure stress, and failure strain for both MV leaflets and chordae.

We describe a rare case of severe low-flow, low-gradient aortic stenosis due to a calcified aortic valve chordae tendineae. The chordae was captured on cardiac computed tomography (CT) using advanced 3-dimensional image reconstruction to reveal the fibrous strand tethering the non-coronary cusp to the left ventricular outflow tract, rendering it functionally immobile. This is one of the first reported cases of severe aortic stenosis from an aortic valve chordae tendineae which highlights the utility of advanced image processing techniques in cardiac CT.

Purpose: The double tendon of extensor digitorum longus (EDL) muscle was observed on the left leg of a 80-year-old male cadaver. Methods: A male cadaver 80 years old was subjected to routine anatomical dissection for research and teaching purposes. Results: The main tendon of the EDL muscle started just at the end of the muscle belly. However, the accessory tendon started at the tendinous end of the muscle as a continuation of the muscle. The main and accessory tendons split into two more slips after passing through the same tunnel below the extensor retinaculum. There was also difference on ending of the tendon slips of EDL muscle. The main tendon divided into two tendinous slips on the dorsum of the foot attached to the second and third toes. The accessory tendon divided into two tendinous slips on the dorsum of the foot attached to the fourth and the fifth toes. Conclusion: Knowledge of the tendons and anatomical differences of this muscle is important for surgeons in interventional procedures involving the dorsum of the foot. [ABSTRACT FROM AUTHOR]

Background MitraClip therapy has become an alternative therapy for primary and secondary mitral regurgitation (MR) in patients at high surgical risk. However, this procedure is associated with several complications. Case summary The patient was a 93-year-old male with severe MR caused by prolapse of the mid-posterior mitral leaflet (P2) and atrial enlargement. His heart failure (HF) continued to worsen, requiring hospitalization. Considering his high surgical risk, the heart team chose MitraClip treatment. After one clip was placed in the centre of the mitral valve (P2 lateral side), MR severity was reduced from severe to trivial. However, immediately after grasping, incessant non-sustained ventricular tachycardia (VT) with a heart rate of 150 beats/min occurred. Since there were no significant ST-T changes on electrocardiogram and no left ventricular (LV) wall motion abnormalities on echocardiography, ischaemic heart disease was ruled out, and pacing with a temporary pacemaker, potassium level correction, and intravenous amiodarone administration were performed. The frequency of VT decreased but it did not disappear. Diuretics were administered for HF, and VT disappeared within a few hours, with no recurrence, probably due to a decrease in the LV chamber size after diuresis. Discussion The VT waveform showed a right bundle branch block pattern with a superior axis. Furthermore, a negative lead I and a transition zone with an abrupt change from V4 to V5 indicated that PVC/VT arose from the posterior papillary muscle area. The probable cause was mechanical extension of the posterior medial papillary muscle as a result of leaflet grasping, with resolution following appropriate volume management. [ABSTRACT FROM AUTHOR]

Current in vitro models of the left heart establish the pressure difference required to close the mitral valve by sealing and pressurizing the ventricular side of the valve, limiting important access to the subvalvular apparatus. This paper describes and evaluates a system that establishes physiological pressure differences across the valve using vacuum on the atrial side. The subvalvular apparatus is open to atmospheric pressure and accessible by tools and sensors, establishing a novel technique for experimentation on atrioventricular valves. Porcine mitral valves were excised and closed by vacuum within the atrial chamber. Images were used to document and analyze closure of the leaflets. Papillary muscle force and regurgitant flow rate were measured to be 4.07 N at 120 mmHg and approximately 12.1 ml/s respectively, both of which are within clinically relevant ranges. The relative ease of these measurements demonstrates the usefulness of improved ventricular access at peak pressure/force closure. [ABSTRACT FROM AUTHOR]

Abstract Background Parachute mitral valve with reticular chordae tendineae is an extremely rare anomaly. Case presentation We present a case of parachute mitral valve associated with distinctive reticular chordae tendineae in an adult. It was diagnosed from the echocardiogram. The patient was referred for surgery. Valve analysis showed thickened mitral valve leaflets and commissures. The chordae tendinae were lengthy and thick. All the chordae tendinae merged into a solitary papillary muscle. A distinctive reticular fibrous tissue was found on mitral valve apparatus as the chordae tendinae intermixed each other. The only functional communication between the left atrium and the left ventricle was through the reticular spaces. This anomaly was considered to be unrepairable and was replaced with a mechanical valve. Conclusions An extremely rare and unique case of parachute mitral valve associated with reticular chordae tendineae was reported. Mitral valve replacement is a reasonable choice in patients with parachute mitral valve with reticular chordae tendineae.

An 81-year-old female patient with a history of severe secondary mitral regurgitation, hypertension, and paroxysmal atrial fibrillation was seen by the valve team to determine candidacy for transcatheter edge-to-edge repair of the mitral valve. Two-dimensional biplane imaging showed a transverse basal left ventricle false tendon attached to papillary muscles. The position was concerning for interference during deployment of the mitral clip. [ABSTRACT FROM AUTHOR]

Objective: Congenital defects/diseases Background: D-transposition of the great vessels (D-TGA) was once a fatal diagnosis within the first year of life. The Mustard and Senning procedures were invented to redirect the blood flow via intra-atrial baffles. The complicated nature of the clinical course and presence of chordal systolic anterior motion of the mitral valve in a patient with D-TGA and prior subpulmonic resection and Alfieri stitching is presented. Case Report: A 41-year-old man presented to the clinic with a chief concern of dyspnea on exertion and chronic chest pain. Diagnosed with D-TGA as an infant, he underwent balloon septostomy and later a Mustard procedure at 3 months of age and subpulmonic resection and Alfieri stitching as an adolescent. The patient now presented with transthoracic echocardiogram-revealed severe turbulence in native left ventricular outflow tract to the pulmonary circulation. Doppler velocities indicated this was originating from chordal systolic anterior motion of the mitral valve. Conclusions: This case reinforces the need for practitioners caring for such patients to become familiarized with and educated in the field of adult congenital heart disease, as patients once plagued with shorter life expectancies are living longer. Repeat surgical intervention or catheter-based therapies may be considered in the future should medical therapy fail to control our patient's symptoms. A multidisciplinary approach and further monitoring of these patients for best practice guidelines would be ideal and beneficial for the patients and practitioners alike. [ABSTRACT FROM AUTHOR]

The surgical management of patients with hypertrophic obstructive cardiomyopathy can be extremely challenging. Relieving the left ventricular outflow tract obstruction in these patients is often achieved by performing a septal myectomy. However, in many instances, septal reduction alone is not enough to relieve the obstruction. Interventions on the sub-valvular apparatus, including the anomalous chordae tendineae and the abnormal papillary muscles, are often required. In this review, we summarize the embryology and the pathophysiology of the different elements that may contribute to the left ventricular outflow tract obstruction in the setting of hypertrophic obstructive cardiomyopathy. In addition, we highlight the different surgical procedures that a surgeon may adopt to relieve the left ventricular outflow tract obstruction, beyond the septal myectomy. [ABSTRACT FROM AUTHOR]

Early detection of chordae tendineae state through medical imaging has a significant impact in reducing the clinical progression of mitral valve disease. This study proposes two methods for tracking these structures. The first method is based on Frangi filter to detect tubular objects while the second one is mainly based on ISODATA clustering approaches. Twenty-eight patients who had previously undergone CT study for mitral valve evaluation were retrospectively enrolled in the study. Pearson correlation coefficients and a linear regression analysis were used to evaluate the correlation between clinical indices measurements for mitral valve segmentation derived from manual segmentation and those obtained through two semi-automated methods. The results showed that MV segmentation based on Frangi filter gave an average Dice index of 0.79 ± 1.52 and a HD of 2.67± 1.14 mm while the ISODATA algorithm indicated an average Dice index of 0.65 ± 0.24 and a HD of 3.26± 0.95 mm. The Pearson correlation coefficients showed a strong correlation between clinical measurements (r= 0.921 for P-A diameter and r=0.987 for MA area, p < 0.01) for mitral valve segmentation derived from manual segmentation and those obtained through Frangi filter method. Similarly, we reported a good correlation between ISDATA and manual segmentation in the measurement of P-A diameter and MA area with respectively r = 0.872 and r = 0.859. The Frangi filter algorithm performs better than the ISODATA algorithm. This suggests that MV segmentation using Frangi filter algorithm gives a performance, which is quite similar to the expert human segmentation. [ABSTRACT FROM AUTHOR]

The chordae tendineae form an important part of atrioventricular apparatus connecting papillary muscles to the valve leaflets. Gross morphology of the chordae tendineae of the left ventricle was studied, and any gender differences were noted. Material and methods: 30 grossly normal cadaveric fixed in 10% formalin were studied. An incision was given along left border of heart to open the left ventricle. Gross morphology of chordae tendineae were studied. Statistical analysis: In the anterior leaflet, two strut chordae were found in both males and females in all the cases. The posterior leaflet of mitral valve showed the presence of rough zone, cleft, and basal chordae. Cleft and basal chordae were seen only in the posterior leaflet of mitral valve and not in the anterior leaflet. The number of rough zone chordae was more in the posterior leaflet than other types of chordae, and they were always present. The extent of the spread of anterolateral commissural chorda was mainly to commissural 1/3 of valve leaflet. In males, the chorda spread to commissural 1/3 of leaflet in all the cases, while in females, it was so in 86.7% of cases only. Posteromedial commissural chorda was present in 96.7% of cases.

Background: Mitral valvuloplasty using artificial chordae tendineae represents an effective surgical approach for treating mitral regurgitation. Achieving precise measurements of artificial chordae tendineae length (CL) is an important factor in the procedure; however, no objective index currently exists to facilitate this measurement. Therefore, preoperative assessment of CL is critical for surgical planning and support. Four-dimensional x-ray micro-computed tomography (4D-CT) may be useful for accurate CL measurement considering that it allows for dynamic three-dimensional (3D) evaluation compared to that with transthoracic echocardiography, a conventional inspection method., Aim: To investigate the behavior and length of mitral chordae tendineae during systole using 4D-CT., Methods: Eleven adults aged > 70 years without mitral valve disease were evaluated. A 64-slice CT scanner was used to capture 20 phases in the cardiac cycle in electrocardiographic synchronization. The length of the primary chordae tendineae was measured from early systole to early diastole using the 3D image. The primary chordae tendineae originating from the anterior papillary muscle and attached to the A1-2 region and those from the posterior papillary muscle and attached to the A2-3 region were designated as cA and cP, respectively. The behavior and maximum lengths [cA (ma), cP (max)] were compared, and the correlation with body surface area (BSA) was evaluated., Results: In all cases, the mitral anterior leaflet chordae tendineae could be measured. In most cases, the cA and cP chordae tendineae could be measured visually. The mean cA (max) and cP (max) were 20.2 mm ± 1.95 mm and 23.5 mm ± 4.06 mm, respectively. cP (max) was significantly longer. The correlation coefficients (r) with BSA were 0.60 and 0.78 for cA (max) and cP (max), respectively. Both cA and cP exhibited constant variation in CL during systole, with a maximum 1.16-fold increase in cA and a 1.23-fold increase in cP from early to mid-systole. For cP, CL reached a plateau at 15% and remained elongated until end-systole, whereas for cA, after peaking at 15%, CL shortened slightly and then moved toward its peak again as end-systole approached., Conclusion: The study suggests that 4D-CT is a valuable tool for accurate measurement of both the length and behavior of chordae tendineae within the anterior leaflet of the mitral valve., Competing Interests: Conflict-of-interest statement: There are no conflicts of interest to report., (©The Author(s) 2024. Published by Baishideng Publishing Group Inc. All rights reserved.)

Background: Artificial chordae implantation has become the most applied method for mitral valve repair. Choosing the proper length of the neochords is the most crucial point in this technique. In order to give the possibility of reversibility and corrections, the authors developed a novel technique in which the lengths of the neochords are determined at the end of the repair by moving a small pericardial lock along the neochords while the shape and competence of the valve is tested. In this simple reproducible technique, the length of the neochords remains adjustable until the very last moment of the repair and is fixed only when the final water test confirms ideal configuration. Methods: Between 2017 and 2023, 123 patients with severe degenerative MR underwent MV repair with pericardial lock technique. 83(67.4%) had pure posterior leaflet prolapse, 24(19.5%) had pure anterior leaflet prolapse and in 17(13.8%) Both leaflets were involved. Minimally invasive approach was used in 106(86.1%) patients. Determining the number and location of the necessary neochords was made after the initial classic valve analysis. The neochords were passed through appropriate papillary muscles and then left alone until the final step, after placing the suitable annuloplasty ring. After passing through the leaflet edges, the neochords were passed twice through a small 2 x 4 mm piece of pericardium. These pericardial locks can move along the neochord with moderate resistance which offers the possibility of adjustment to find the best suitable configuration of the leaflet confirmed by water tests. Results: The median follow up time was 34.3 months. The mean number of neochords used for each patient was 2.57 ±0.99 (1-6). Most patient received neochords on P2(82), followed by A2(36), p3(32), A3(26), p1(24), and A1(10). There was no mortality in patients. One patient was reoperated and repaired 8 months after surgery for severe MR due to anterior leaflet perforation at the site of annuloplasty suture. There was one mild MR and one Moderate MR in the early echocardiography, both with fibroelastic deficiency and small anterior leaflets. Significant MR(moderate or more) was seen in 6(4.8%)patients during follow up while 25 (20.3%) had mild MR and 82 (66.6%) had no or trivial MR. Conclusion: The pericardial lock technique is simple and reproducible with the advantage of secure fixation, and the possibility of correction of neochord length. Adjustability and reversibility until the last stage of the repair, increases the confidence and security of the surgeon and at the same time guaranties the most proper configuration and geometry of the valve. [ABSTRACT FROM AUTHOR]

In a 3-year-old Samoyed, aortic bulging was found on radiography during a general check-up. On echocardiography, turbulent flow was found in left ventricular outflow tract (LVOT) with high velocity (6.1 m/s). A linear structure was attached to the interventricular septum and connected to the chordae tendineae reaching the papillary muscle. A part of the structure moved during cardiac cycle, similar to mitral motion. This dog was diagnosed with LVOT obstruction caused by accessory mitral valve tissue (AMVT). This is the first report of AMVT in veterinary medicine. AMVT should be considered as a possible cause of LVOT obstruction in dogs. [ABSTRACT FROM AUTHOR]

Background: Parachute mitral valve with reticular chordae tendineae is an extremely rare anomaly.Case Presentation: We present a case of parachute mitral valve associated with distinctive reticular chordae tendineae in an adult. It was diagnosed from the echocardiogram. The patient was referred for surgery. Valve analysis showed thickened mitral valve leaflets and commissures. The chordae tendinae were lengthy and thick. All the chordae tendinae merged into a solitary papillary muscle. A distinctive reticular fibrous tissue was found on mitral valve apparatus as the chordae tendinae intermixed each other. The only functional communication between the left atrium and the left ventricle was through the reticular spaces. This anomaly was considered to be unrepairable and was replaced with a mechanical valve.Conclusions: An extremely rare and unique case of parachute mitral valve associated with reticular chordae tendineae was reported. Mitral valve replacement is a reasonable choice in patients with parachute mitral valve with reticular chordae tendineae. [ABSTRACT FROM AUTHOR]

Strut chordae, on their own, are not typically thought to aid mitral valve competence. The aim of this study is to assess whether strut chordae aid mitral valve competence during acute annular dilation. Twelve porcine hearts were dissected and tested using an in vitro simulator, with the mitral annulus tested in either a 'normal' or a dilated configuration. The normal configuration included a diameter of 30 mm, a posterior leaflet 'radius' of 15 mm and a commissural corner 'radius' of 7.5 mm; the dilated annular template instead used dimensions of 50 mm, 25 mm and 12.5 mm, respectively. Each mitral valve underwent ten repeat tests with a target systolic pressure of 100 mmHg. No significant difference in the pressure was detected between the dilated and regular annuli for the mitral valves tested (95 ± 3 mmHg cf. 95 ± 2 mmHg). However, the volume of regurgitation for a dilated annulus was 28 ml greater than for a valve with a normal annulus. Following severing of strut chordae, there was a significant reduction in the systolic pressure withstood before regurgitation by mitral valves with dilated annuli (60 ± 29 mmHg cf. 95 ± 2 mmHg for normal annular dimensions; p < 0.05). In conclusion, strut chordae tendineae may play a role in aiding mitral valve competence during pathophysiology. [ABSTRACT FROM AUTHOR]

Mitral valve repair is typically performed by implanting a ring-like device at the valve annulus to reshape the annulus and to improve leaflet coaptation. In most cases, some additional procedures are needed, including leaflet resection and artificial chordae implantation. However, artificial chordae implantation could be technically challenging and postoperative left ventricular remodeling could increase the risk of recurrent mitral regurgitation. We propose an innovative annular device made of chromo-cobalt, finalized not only to reshape the annulus but also to enable anchoring of leaflets to a fixed intraventricular structure. Durability evaluation of the device was tested by applying eight radial force vectors equally spaced along the ring and related fatigue analysis. To evaluate the efficacy of the mitral valvuloplasty using the tested ring, the device was implanted in five adult swine hearts. Functional analysis of the ring was performed by measuring left ventricular pressure and fluid volume loss, following implantation in normal and dysfunctional mitral valve leaflets. Both fatigue and functional analysis showed satisfactory and promising results in terms of durability and efficacy of mitral valve repair. Because of its favorable durability and functional characteristics this device appears promising and provides good results in terms of valve competence, thus avoiding both manipulations of papillary muscles and interference in left ventricular hemodynamics. However, an in vivo test is mandatory to fully understand the impact of the device on subvalvular apparatus. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether the mechanical properties of mitral valve chordae tendineae are sensitive to being cross-linked under load. A total 64 chordae were extracted from eight porcine hearts. Two chordae (posterior basal) from each heart were subjected to uniaxial ramp testing and six chordae (two strut, two anterior basal and two posterior basal) were subjected to dynamic mechanical analysis over frequencies between 0.5 and 10 Hz. Chordae were either cross-linked in tension or cross-linked in the absence of loading. Chordae cross-linked under load transitioned from high to low extension at a lower strain than cross-linked unloaded chordae (0.07 cf. 0.22), with greater pre-transitional (30.8 MPa cf. 5.78 MPa) and post-transitional (139 MPa cf. 74.1 MPa) moduli. The mean storage modulus of anterior strut chordae ranged from 48 to 54 MPa for cross-linked unloaded chordae, as compared to 53–61 MPa cross-linked loaded chordae. The mean loss modulus of anterior strut chordae ranged from 2.3 to 2.9 MPa for cross-linked unloaded chordae, as compared to 3.8–4.8 MPa cross-linked loaded chordae. The elastic and viscoelastic properties of chordae following glutaraldehyde cross-linking are dependent on the inclusion/exclusion of loading during the cross-linking process; with loading increasing the magnitude of the material properties measured. [ABSTRACT FROM AUTHOR]

There is a great demand for development of a functional tricuspid regurgitation (FTR) model for accelerating development and preclinical study of tricuspid interventional repair devices. This study aimed to develop a severe FTR model by creating a tissue-silicone integrated right ventricular pulsatile circulatory simulator. The simulator incorporates the porcine tricuspid annulus, valve leaflets, chordae tendineae, papillary muscles, and right ventricular wall as one continuous piece of tissue, thereby preserving essential anatomical relationships of the tricuspid valve (TV) complex. We dilated the TV annulus with collagenolytic enzymes under applying stepwise dilation, and successfully achieved a severe FTR model with a regurgitant volume of 45 ± 9 mL/beat and a flow jet area of 15.8 ± 2.3 cm 2 (n = 6). Compared to a normal model, the severe FTR model exhibited a larger annular circumference (133.1 ± 8.2 mm vs. 115.7 ± 5.5 mm; p = 0.009) and lower coaptation height (6.6 ± 1.0 mm vs. 17.7 ± 1.3 mm; p = 0.003). Following the De-Vega annular augmentation procedure to the severe FTR model, a significant reduction in regurgitant volume and flow jet area were observed. This severe FTR model may open new avenues for the development and evaluation of transcatheter TV devices., (© 2024. The Author(s).)

The AtriClip device enables the safe and reproducible epicardial clipping of the left atrial appendage. Transapical off-pump beating heart mitral valve repair using NeoChord DS100 Artificial Chordae Delivery System has matured and become more standardized. We aim to evaluate the feasibility of combining NeoChord repair and left atrial appendage exclusion in a single procedure through the same minithoracotomy in patients with mitral valve prolapse and atrial fibrillation. From 2018 to 2019, seven patients with severe mitral regurgitation and atrial fibrillation underwent transesophageal echocardiography-guided transapical off-pump mitral valve repair with the novel NeoChord DS 1000 system and concomitant left atrial appendage exclusion using the AtriClip Pro II device. Both procedures were performed via left mini-thoracotomy. The AtriClip device was applied after the NeoChord repair was done. All seven patients had less than moderate mitral regurgitation after the NeoChord repair and successful left atrial appendage occlusion. There were no device or procedure-related complications. Clinical follow-up revealed significant symptomatic improvement, and no cardiovascular complications were reported. Transesophageal echocardiography at 6-12 months post-procedure showed stable left atrial appendage occlusion with no residual flow between the left atrium and the left atrial appendage and a stump of less than 5 mm. Beating heart epicardial clipping of the left atrial appendage using AtriClip concomitant with transapical mitral valve repair using Neochord DS 1000 system is a feasible and safe treatment option in mitral valve prolapse and atrial fibrillation in patients with limited indications. However, its safety needs to be confirmed in a larger series of patients., (© 2023. The Japanese Society for Artificial Organs.)