Evaluation of mitral chordae tendineae length using four-dimensional computed tomography.

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.

Combination of an extremely rare and a common congenital valvular anomalies: Accessory mitral valve chordae from left atrium and bicuspid aortic valve.

Accessory chordae tendineae is an extremely rare anomaly. In this case report, we described a 61-year-old female patient newly diagnosed with the combination of an accessory mitral valve chordae extending from left atrium which is an extremely rare congenital anomaly and a bicuspid aortic valve. In our patient, three-dimensional echocardiography showed incremental value over two-dimensional echocardiography in the assessment of the exact localization and the extend of accessory chordea.

Gene expression of Postn and FGF7 in canine chordae tendineae and their effects on flexor tenocyte biology.

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.

Lead helix winding tricuspid chordae tendineae: A case report.

BACKGROUND: As left bundle branch pacing (LBBP) is more like physiological pacing, LBBP has emerged as a novel pacing strategy that uses the native conduction system to improve ventricular synchronization with stable pacing parameters. LBBP has been revealed associated with a significantly reduced risk of new-onset atrial fibrillation and heart failure compared with conventional permanent pacemaker implantation. CASE SUMMARY: A 64-year-old man was admitted with a 24-h history of chest distress and shortness of breath, which continued unabated. The patient had no symptoms of chest pain, dizziness, syncope, nausea nor vomiting. There were no abnormalities found in routine examinations after admission. Twelve-lead electrocardiogram presented a result of 2:1 atrioventricular block. Coronary angiography was performed the next day and no abnormality was found. Finally, the patient agreed to received LBBP and signed the informed consent. During the process of withdrawing the Medtronic Model 3830 lead into sheath, we found the lead helix was wrapped around the chordae tendineae of the septal valve of tricuspid. Attempts to rotate the 3830 lead failed to release the lead helix from the chordae tendineae, and ultimately we used radiofrequency ablation to ablate the wrapped chordae tendineae. CONCLUSION: Radiofrequency ablation effectively solved this problem without complications. It is an effective and reliable method to resolve lead winding chordae.

Insights Into Interaction Between Clip Device and the Mitral Valve Apparatus in the Human Heart.

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 extremely rare case of aortic chordae tendineae strands: A case report with literature review.

The aortic chordae tendineae strands (ACTS) is a rare complication that can induce aortic regurgitation. Reported cases of ACTS are very few, and this is the first case reported in Iran. Patients with unexplained aortic regurgitation should be carefully evaluated for ACTS, which can be easily observed by TEE; a decision regarding aortic valve surgery should be made based on the severity of AR. Herein we reported A 64-year-old male was admitted to our hospital for dyspnea on exertion. In transthoracic Echocardiography a fibrous band-like chordae in the aortic root attached to the noncoronary cusp of the aorta was seen, which caused retraction of the noncoronary cusp, mal-coaptation of the aortic valves, and severe eccentric jet posterior directed aortic regurgitation. As a result of the ACTS, the patient was diagnosed with severe aortic regurgitation (AR); due to the symptomatic severe AR, the patient underwent aortic valve surgical replacement.

Comparative modeling of the mitral valve in normal and prolapse conditions.

Introduction: Computational modeling is one of the best non-invasive approaches to predicting the functional behavior of the mitral valve (MV) in health and disease. Mitral valve prolapse (MVP) due to partial or complete chordae tendineae rapture is the most common valvular disease and results in mitral regurgitation (MR). Methods: In this study, Image-based fluid-structure interaction (FSI) models of the human MV are developed in the normal physiological and posterior leaflet prolapse conditions. Detailed geometry of the healthy human MV is derived from Computed Tomography imaging data. To provide prolapse condition, some chords attached to the posterior leaflet are removed from the healthy valve. Both normal and prolapsed valves are embedded separately in a straight tubular blood volume and simulated under physiological systolic pressure loads. The Arbitrary Lagrangian-Eulerian finite element method is used to accommodate the deforming intersection boundaries of the blood and MV. Results: The stress values in the mitral components, and also flow patterns including the regurgitant flow rates are obtained and compared in both conditions through the simulation. These simulations have the potential to improve the treatment of patients with MVP, and also help surgeons to have more realistic insight into the dynamics of the MV in health and prolapse. Conclusion: In the prolapse model, computational results show incomplete leaflet coaptation, higher MR severity, and also a significant increment of posterior leaflet stress compared to the normal valve. Moreover, it is found more deviation of the regurgitant jet towards the left atrium wall due to the posterior leaflet prolapse.

Resolution of congestive heart failure and reverse remodeling in two Chihuahuas with flail mitral valve leaflets.

Development of a flail mitral valve (MV) leaflet secondary to ruptured chordae tendineae in the setting of myxomatous mitral valve disease is a known complication of the disease that often results in severe mitral regurgitation. Two cases are presented in which a flail anterior MV leaflet caused severe mitral regurgitation and led to the development of congestive heart failure in male castrated Chihuahuas. Over variable periods of time, repeat cardiac evaluation disclosed reverse left-sided cardiac remodeling and lessened mitral regurgitation that allowed for withdrawal of furosemide in both dogs. While rare, improvement in mitral regurgitation severity may occur without surgical intervention, allowing for reverse left-sided cardiac remodeling and discontinuation of furosemide.

Atypical Left Ventricular False 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.

Aortic valve chordae tendineae: A rare cause of aortic stenosis.

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.

Shannon entropy as a reliable score to diagnose human fibroelastic degenerative mitral chords: A micro-ct ex-vivo study.

This paper is aimed at identifying by means of micro-CT the microstructural differences between normal and degenerative mitral marginal chordae tendineae. The control group is composed of 21 normal chords excised from 14 normal mitral valves from heart transplant recipients. The experimental group comprises 22 degenerative fibroelastic chords obtained at surgery from 11 pathological valves after mitral repair or replacement. In the control group the superficial endothelial cells and spongiosa layer remained intact, covering the wavy core collagen. In contrast, in the experimental group the collagen fibers were arranged as straightened thick bundles in a parallel configuration. 100 cross-sections were examined by micro-CT from each chord. Each image was randomized through the K-means machine learning algorithm and then, the global and local Shannon entropies were obtained. The optimum number of clusters, K, was estimated to maximize the differences between normal and degenerative chords in global and local Shannon entropy; the p-value after a nested ANOVA test was chosen as the parameter to be minimized. Optimum results were obtained with global Shannon entropy and 2≤K≤7, providing p < 0.01; for K=3, p = 2.86·10-3. These findings open the door to novel perioperative diagnostic methods in order to avoid or reduce postoperative mitral valve regurgitation recurrences.

Incessant non-sustained ventricular tachycardia immediately after MitraClip placement: a case report.

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.

Acute aortic regurgitation due to fibrous strand rupture.

A 60-year-old male presented with sudden onset chest pain and pulmonary edema. The investigation confirmed torrential aortic regurgitation of a bicuspid valve. At surgery, a ruptured fibrous strand was identified which had been supporting the left-right cusp commissure with loss of attachment to the aortic wall. This case demonstrates that fibrous strands may be present as a supporting structure of the aortic valve, and rupture can be a rare cause of torrential aortic regurgitation, similar in pathogenesis to how it may be associated with acute severe mitral regurgitation and chordae tendineae rupture.

Cadaveric Study on the Morphology and Morphometry of Heart Papillary Muscles.

Introduction A normal atrioventricular valve complex of the heart consists of the atrioventricular (A-V) ring, cusps, chordae tendineae, and papillary muscles. The right ventricle contains three while the left ventricle contains only two papillary muscles, which are named according to their location. A thorough understanding of the normal anatomy as well as possible variations can help surgeons in various corrective surgeries involving papillary muscles. Material & methods The study included 50 formalin-preserved hearts procured from human cadavers of unknown age and cause of death. The number of papillary muscles along with their shape, size, and pattern were noted separately for each ventricle. Data were analyzed using SPSS Version 21.0 (IBM Corp., Armonk, NY). Results The left and right ventricles contained two and three papillary muscles, respectively, in all the hearts. In the right ventricles, conical shape and the single base and divided apex (SBDA) pattern were found to be most prevalent. Anterior papillary muscles exhibited the mean length of 12.71±3.81 and 16.41±4.33 in the right and left ventricles, respectively. Similarly, posterior papillary muscles exhibited a mean length of 12.40±3.03 and 14.64±3.92 in the right and left ventricles, respectively. Both differences were found to be statistically significant Conclusion For the appropriate functioning of valves, both anatomical and mechanical coherence of the papillary muscles is required. A very keen understanding of this valvular complex is thus essential for anatomists, physiologists, and cardiologists to deal with normal as well as pathological valvular conditions.

In Vitro Mitral Valve Model with Unrestricted Ventricular Access: Using Vacuum to Close the Valve and Enable Static Trans-Mitral Pressure.

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.

Incidental TEE finding of aberrant chordae tendineae insertion into the basal septum.

A 65-year-old female with severe mitral regurgitation presenting for mitral valve replacement was found to have a previously undiagnosed aberrant papillary muscle with thickened chordae tendineae inserting into the basal septum during intra-operative TEE. Despite its anatomic location, there was no evidence that the aberrant papillary muscle was contributing to the mitral regurgitation or causing left ventricular outflow tract (LVOT) obstruction. The aberrant papillary muscle was resected during the operation and the patient was separated from cardiopulmonary bypass without complications.

Comprehensive left ventricular outflow tract management beyond septal reduction to relieve obstruction.

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.

Morphology of the papillary muscles and the chordae tendineae of the ventricles of adult human hearts.

INTRODUCTION: The papillary muscles (PM) play a vital role in atrioventricular (AV) valve function. The PM and their chordae tendineae (CT) regulate the closure of the AV valve during systole. The present study was undertaken to categorize the PM based on their shapes and variant patterns and CT based on their types and the branching pattern. METHODS: This study included formalin-fixed ten adult cadaveric heart specimens. We observed the number, shape, length, breadth, pattern, and presence of extra PM. The number of chordae attached to the tip of each PM was quantified. We classified the types and branching patterns of the chordae and their pattern of attachment to the cusps. RESULTS: In the right ventricle, conical, truncated, and flat-topped PM were observed. The anterior PM had 5.3 ± 1.9, the posterior PM had 2.7 ± 2.1, and the septal PM had 3.5 ± 2.3 CT attached to it. In the left ventricle, we observed conical, truncated, flat-topped, bifurcate, and trifurcate shapes of PM. The anterior and the posterior PM had 7.7 ± 2.8 and 7.7 ± 2.7 CT attached to them, respectively. The true CT were cusp, cleft, and commissural and the false CT were pillar-wall, inter-pillar, and strut. We also found 3 branching patterns for the chordae (single, fan-shaped, and web forming). CONCLUSION: The study explored the comparative morphology of PM and chordae in the right and left ventricles. The knowledge of the morphological pattern of PM and CT would contribute to the valvular function and aid in diagnosing conditions such as valve prolapse or regurgitation.

Structural and biomechanical characterizations of acellular porcine mitral valve scaffolds: anterior leaflets, posterior leaflets, and chordae tendineae.

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.