Understanding the cell fate and behavior of progenitors at the origin of the mouse cardiac mitral valve.

Congenital heart malformations include mitral valve defects, which remain largely unexplained. During embryogenesis, a restricted population of endocardial cells within the atrioventricular canal undergoes an endothelial-to-mesenchymal transition to give rise to mitral valvular cells. However, the identity and fate decisions of these progenitors as well as the behavior and distribution of their derivatives in valve leaflets remain unknown. We used single-cell RNA sequencing (scRNA-seq) of genetically labeled endocardial cells and microdissected mouse embryonic and postnatal mitral valves to characterize the developmental road. We defined the metabolic processes underlying the specification of the progenitors and their contributions to subtypes of valvular cells. Using retrospective multicolor clonal analysis, we describe specific modes of growth and behavior of endocardial cell-derived clones, which build up, in a proper manner, functional valve leaflets. Our data identify how both genetic and metabolic mechanisms specifically drive the fate of a subset of endocardial cells toward their distinct clonal contribution to the formation of the valve.

An Undiagnosed Shone Complex in a 52-Year-Old Female: A Case Report.

Shone complex (SC) is a rare congenital heart disease characterized by four obstructive anomalies, including parachute mitral valve (PMV), left atrial supra-valvular ring, subaortic stenosis, and coarctation of the aorta. Typically, SC manifests early in life. However, we encountered a 52-year-old female with a history of hypertension diagnosed at 26 years and left-sided weakness poststroke. She presented with worsening dyspnea and palpitations, prompting a thorough investigation. Echocardiography revealed a heavily calcified bicuspid aortic valve with severe aortic stenosis and parachute mitral valve with severe mitral stenosis and preserved ejection fraction, raising suspicions regarding the presence of SC. Cardiac catheterization, aortic-angiography, and noncontrast chest computed tomography (CT) revealed abrupt occlusion of the postductal aorta, giving a picture of aortic coarctation with well-established collateral vessels including prominent right and left internal mammary arteries. So, she was diagnosed with an incomplete SC at the age of 52. Shone complex is a rare congenital heart disease that typically presents in early childhood, but late presentations due to misdiagnosis or incomplete work up are possible. This case emphasizes the rarity of late presentations of SC and highlights the importance of early diagnosis and intervention to improve outcomes. An incomplete SC should be considered in adult patients presenting with left-sided obstructive lesions.

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.

Role of 3D transoesophageal echocardiography in correct diagnosis of congenital isolated double orifice mitral valve in a young adult misdiagnosed as rheumatic heart disease.

Double orifice mitral valve (DOMV) is an extremely rare congenital anomaly of the mitral valve (MV) wherein the MV orifice divides into two separate orifices by an accessory fibrous band.Isolated DOMV is a rarity and is often discovered incidentally. It may be associated with other congenital conditions wherein it is identified in early childhood. Its prevalence and prognostic relevance in adulthood remain unclear. DOMV patients may be asymptomatic or have symptoms due to mitral stenosis or regurgitation. We present a case of an asymptomatic young adult initially diagnosed with rheumatic mitral stenosis. However, after a thorough echocardiographic assessment, including three-dimensional transesophageal echocardiography, the accurate diagnosis of DOMV was made.

Redo mitral valve replacement in an adult with severe pulmonary hypertension resulting from structural valve deterioration and left ventricular outflow tract obstruction and a history of atrioventricular septal defect repair: a case report.

BACKGROUND: Pulmonary hypertension (PH)-associated with left heart disease (Nice PH classification group II) improves when the latter is treated; however, the treatment of PH concomitant with group I PH due to congenital heart disease is difficult, and the optimal pharmacotherapy is controversial. Intervention strategies for the left-sided atrioventricular valve in partial atrioventricular septal defect (AVSD) are problematic. CASE PRESENTATION: A 37-year-old woman who had undergone patch closure for a partial AVSD and mitral valve replacement with a rather large bioprosthesis at the juxta-annular position for mitral regurgitation 12 years earlier was referred to our institute because of severe PH. Echocardiography revealed calcification resulting in severe stenosis of the bioprosthesis and protrusion of its stent post into the left ventricular outflow tract; therefore, redo mitral valve replacement at the supra-annular position was performed using a mechanical valve. Combined group I and II PH gradually improved with meticulous postoperative medical management. CONCLUSIONS: Severe PH due to stent post protrusion and structural valve deterioration in AVSD was successfully treated with redo mitral valve replacement. The present case was complicated with group I and II PH, for which medical therapy in conjunction with surgical treatment yielded an optimal therapeutic effect.

Accessory mitral valve tissue: a differential diagnosis of an obstructive mass on the left ventricular outflow tract.

Accessory mitral valve tissue is a rare congenital cardiac anomaly that is typically discovered incidentally during echocardiographic evaluation prompted by an asymptomatic murmur. This pathology has characteristic echocardiographic elements and is usually associated with other CHD. The decision to perform surgical resection depends on factors such as the degree of obstruction, presence of symptoms, presence of other CHDs, and risk of thrombosis. The researchers hereby present a case of an asymptomatic paediatric patient with accessory mitral valve tissue that produced left ventricular outflow tract obstruction.

Which Phenotypes Should We Include in the Hypoplastic Left Heart Syndrome?

The recent special issue of the World Journal for Pediatric and Congenital Heart Surgery devoted to hypoplastic left heart syndrome, and its related anomalies, contained significant information of great clinical relevance. Very little attention, however, was devoted to the integrity of ventricular septum as providing a criterion to distinguish between the phenotypes to be included within the syndrome, as opposed to the related anomalies. In this commentary, we summarize the evidence in support of the notion that the phenotypes to be included within the syndrome can be interpreted on the basis of an acquired disease of fetal life. We suggest that it is the integrity of the ventricular septum that provided the major criterion for the distinction between the lesions making up the syndrome and the related anomalies. The subsets of lesions to be included within the syndrome can then be recognized in terms of the time, subsequent to the closure of the embryonic interventricular communication, at which the left ventricle ceased its growth relative to the remainder of the cardiac components. On this basis, it is possible to recognize the combinations of aortic and mitral atresia, mitral stenosis with aortic atresia, combined mitral and aortic stenosis, and hypoplasia of the left ventricle with commensurate hypoplasia of the aortic and mitral valves; the latter combination now recognized as the hypoplastic left heart complex.

Surgical outcomes of double-orifice mitral valve repair in patients with atrioventricular canal defects: a systematic review and meta-analysis.

INTRODUCTION: Double-orifice mitral valve or left atrioventricular valve is a rare congenital cardiac anomaly that may be associated with an atrioventricular septal defect. The surgical management of double-orifice mitral valve/double-orifice left atrioventricular valve with atrioventricular septal defect is highly challenging with acceptable clinical outcomes. This meta-analysis is aimed to evaluate the surgical outcomes of double-orifice mitral valve/double-orifice left atrioventricular valve repair in patients with atrioventricular septal defect. METHODS AND RESULTS: A total of eight studies were retrieved from the literature by searching through PubMed, Google Scholar, Embase, and Cochrane databases. Using Bayesian hierarchical models, we estimated the pooled proportion of incidence of double-orifice mitral valve/double-orifice left atrioventricular valve with atrioventricular septal defect as 4.88% in patients who underwent surgical repair (7 studies; 3295 patients; 95% credible interval [CI] 4.2-5.7%). As compared to pre-operative regurgitation, the pooled proportions of post-operative regurgitation were significantly low in patients with moderate status: 5.1 versus 26.39% and severe status: 5.7 versus 29.38% [8 studies; 171 patients]. Moreover, the heterogeneity test revealed consistency in the data (p < 0.05). Lastly, the pooled estimated proportions of early and late mortality following surgical interventions were low, that is, 5 and 7.4%, respectively. CONCLUSION: The surgical management of moderate to severe regurgitation showed corrective benefits post-operatively and was associated with low incidence of early mortality and re-operation.

A rare coexistence: Hammock mitral valve and aortopulmonary window.

Congenital mitral stenosis is a broad-spectrum pathology in which blood flow to the left ventricle is obstructed both functionally and anatomically. Hammock mitral valve, also known as anomalous mitral arcade, is a rare congenital anomaly particularly in infants and children. Hammock mitral valve may not be suitable for repair regarding the advanced dysplastic mitral valve structure. Aortopulmonary window is an unusual cardiac anomaly which is defined as a communication between the main pulmonary artery and the ascending aorta. As a result of the excessive left-to-right shunt, early intervention and surgical closure deemed mandatory to avoid development of severe pulmonary hypertension and its consequences. All patients with an aortopulmonary window necessitates prompt repair immediately. In this brief report, mitral valve replacement with a mechanical valve and repair of aortopulmonary window with a Dacron patch were performed simultaneously in a 5-month-old patient with a hammock mitral valve and accompanying aortopulmonary window.

Multiple ventricular septal defects associated to anomalous venous returns, mitral valve disease, myocardium hypertrophy, and right outflow obstruction: a multimodality imaging assessment.

We report a rare congenital heart disease characterized by multiple ventricular septal defects associated to anomalous systemic and pulmonary venous returns, marked apical myocardial hypertrophy of both ventricles and of right outflow, and hypoplastic mitral anulus. Multimodality imaging is mandatory to assess anatomical details.

Infant Mitral Valve Replacement: Current State of the Art.

Mitral valve replacement (MVR) in the very young is an imposing clinical challenge. Early and late mortality risk is substantial, severe adverse events are common, and redo mitral valve replacement is inevitable. Therapeutic options are limited. In the older infant with an annulus of 17mm or larger, mechanical MVR is associated with low risk of mortality and predictable durability. For the very young with annular hypoplasia, bovine jugular vein conduit MVR appears to offer equivalent or better early outcomes with the possibility of subsequent valve expansion, potentially prolonging the interval to redo MVR. Experience with cylinder MVR and other forms of surgeon-manufactured MVR is quite limited, and there is currently no information on late outcomes or durability.

Left ventricular outflow tract obstruction caused by a congenital accessory mitral valve leaflet and treated by open-heart surgery in a young dog.

A 3-month-old Shetland sheepdog presented with a loud ejection murmur and exercise intolerance. Echocardiography revealed an accessory mitral valve leaflet, characterised by a valve-like structure separate from the mitral valve seen in the subaortic region of the ventricular septum. The left ventricular outflow tract was partially obstructed with a pressure gradient of 12 mmHg. Accessory mitral valve leaflet resection and mitral valvuloplasty were performed during open-heart surgery. Histology performed on the membrane-like structures were indicative of fibrous connective tissues. Postoperative echocardiography confirmed removal of the valve-like structure with resolution of the left ventricular outflow tract obstruction. The pressure gradient was decreased to 4.6 mmHg. The dog was in good condition and no further treatment was required 5 months after surgery. Both cardiac troponin I and NT-proBNP were markedly decreased. In this dog, surgical resection combined with mitral valve plasty resolved the left ventricular outflow tract obstruction and the clinical signs.

Midterm Outcomes After Surgical Management for Mitral Valve Regurgitation in Infancy.

BACKGROUND: Mitral valve repair is preferred for pediatric mitral valve disease. However, it is technically difficult because of complex lesions, poor surgical exposure, and tissue fragility, especially in infants. We investigated the midterm outcomes of mitral valve surgery for mitral regurgitation in infancy. METHODS: We retrospectively reviewed 18 patients (aged <12 months old) undergoing mitral valve surgery for mitral regurgitation at our institution between October 2005 and March 2019. The patients had 10 acquired and 8 congenital valve lesions as follows: torn chordae (n = 6), leaflet prolapse (n = 4), posterior leaflet hypoplasia (n = 3), anterior leaflet cleft (n = 2), infective endocarditis (n = 1), papillary muscle rupture (n = 1), and hammock valve (n = 1). RESULTS: All patients initially underwent mitral valve repair. There was no operative mortality, and 1 case of late death. The median follow-up period was 7 years and 9 months. Reoperation was performed in 3 patients, re-repair (twice) in 1 patient with a hammock valve, and mitral valve replacement in 2 patients. Fifteen patients had at most mild mitral regurgitation at the last follow-up. A transmitral mean pressure gradient of over 5 mm Hg was observed in 3 cases, including the patient with a hammock valve. Postoperative mitral annular diameter increased within the normal range in all patients. Survival and reoperation-free rates at 5 and 10 years were 94.4% and 83.0%, respectively. CONCLUSIONS: Mitral valve repair for mitral regurgitation in infancy is safe and feasible with satisfactory midterm outcomes, even under serious preoperative conditions.

Imaging of Left Ventricular Hypoplasia.

Left ventricular hypoplasia is a common finding in various forms of congenital heart disease. Echocardiography in the setting of left ventricular hypoplasia must comprehensively assess the size and function of all left-sided structures including the mitral valve, left ventricular outflow tract, aortic valve and aortic arch. Of most importance in any variation of left ventricular hypoplasia is the left ventricular inlet. In neonates, the left ventricular inlet often determines the adequacy of the left ventricle and is the most difficult component to treat surgically.

Incidental detection of accessory mitral valve in adolescent with atrial septal defect: Diagnosis with 3D transesophageal echocardiography and excision with transaortic method.

BACKGROUND: Accessory mitral valve tissue (AMVT) is an extremely rare causes left ventricular outflow tract (LVOT) obstruction and is usually incidentally detected in childhood. It is often associated with other cardiac and vascular congenital malformations. CASE PRESENTATION: In this case, we present a 15-year-old girl was diagnosed with AMVT by transesophageal echocardiography, resulting in LVOT obstruction during systole. Interestingly enough, the patient's accessory mitral valve remained undetected for years until he became symptomatic for wide ASD. Successful closure of the ASD with resection of the AMVT was performed with a transaortic approach. The patient was hemodynamically stable postoperatively. There were no abnormalities in the mitral valves and LVOT. CONCLUSION: It was also unusual to see AMVT with ASD instead of other frequently associated other congenital anomalies. Accessory mitral valve should be considered a rare but important cause of left ventricular outflow tract obstruction in childhood.

Robotic mitral valve plasty for isolated clefts of mitral valve leaflets.

A 21-year-old female patient referred to our institute had been suffering from severe mitral valve regurgitation due to a rare anomaly: a typical cleft at the posterior mitral leaflet and the other partial one at the anterior leaflet. We successfully fixed the mitral valve using the robot-assisted totally endoscopic technique which could perform suture closure of both leaflets and annuloplasty. This communication is the first report of the robotic and totally endoscopic procedure which could treat this rare mitral anomaly.

Atypical Shone's Complex Diagnosed at 70 Years Old: Presenting with Double-orifice Mitral Valve, Bicuspid Aortic Valve, and Aortic Coarctation.

Atypical Shone's complex is a rare congenital anomaly involving a left-sided obstructive lesion of two or three cardiovascular levels. A 70-year-old man with dyspnea on exertion was diagnosed with severe aortic stenosis (AS) with a bicuspid valve, complicated by severe aortic coarctation (CoA) and a double-orifice mitral valve. He underwent surgery for AS and CoA in one session. It is important to search for complicated malformations, even in cases of bicuspid aortic valve found in old age.