Evaluation of mitral chordae tendineae length using four-dimensional computed

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.

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.

Application of real-time 3d echocardiography in mitral valve repair for replacement of chordae tendineae

Objective To investigate the surgical technique and outcomes of replacement of chordae tendineae in mitral valve repair,and evaluate the value of real-time three-di-mensional transesophageal echocardiography in the perioperative period. Methods Thirty-one patients with mitral valve prolapse underwent mitral valve repair using chordae tendineae replacement concomitant with implantation

Left ventricular false tendons and electrocardiogram repolarization abnormalities in healthy young subjects

AIM To describe echocardiographically left ventricular false tendon characteristics and the correlation with ventricular repolarization abnormalities in young athletes.METHODS Three hundred and sixteen healthy young athletes from different sport disciplines were evaluated from 2009 to 2011 during routine screening for agonistic sports eligibility. All subjects, as part of standard preparticipation screening medical evaluation, underwent a basal and post step test 12-lead electrocardiogram(ECG). The athletes with abnormal T-wave flattening and/or inversion were considered for an echocardiogram evaluation and an incremental maximal exercise test on a cycle ergometer. Arterial blood pressure and heart rate, during and after exercise, were also measured.RESULTS Twenty-one of the 316 subjects(6.9%) showed false tendons in the left ventricle. The majority of false tendons(52.38%) were localized between the middle segments of the inferior septum and the lateral wall, 19.06% between the distal segments of the septum and the lateral wall, in 5 subjects between the middle segments of the anterior and inferior walls, and in one subject between the middle segments of the anterior septum and the posterior wall. ECG abnormalities, represented by alterations of ventricular repolarization, were found in 11 subjects(52.38%), 90% of these anomalies were T wave abnormalities from V1 to V3. These anomalies disappeared with an increasing heart rate following the three minute step test as well as during the execution of the maximal exercise.CONCLUSION Left ventricular false tendons are frequently localized between the middle segments of the inferior septum and the lateral wall and are statistically associated with ventricular repolarization abnormalities.

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 porcine𝛼-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.Never-theless,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 af-ter 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.