Prevalence and clinical outcome of mitral-valve prolapse

Cardiac Involvement in Facioscapulohumeral Muscular Dystrophy (FSHD)

Background: Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common muscular dystrophies and predominantly affects facial and shoulder girdle muscles. Previous case reports and cohort studies identified minor cardiac abnormalities in FSHD patients, but their nature and frequency remain incompletely characterized. Methods: We reviewed cardiac, neurological and genetic findings of 104 patients with genetically confirmed FSHD. Results: The most common conduction abnormality was complete (7%) or incomplete (5%) right bundle branch block (RBBB). Bifascicular block, left anterior fascicular block, complete atrioventricular block, and 2:1 atrioventricular block each occurred in 1% of patients. Atrial fibrillation or flutter were seen in 5% of patients. Eight percent of patients had heart failure with reduced ejection fraction and 25% had valvular disease. The latter included aortic stenosis in 6% (severe in 4% and moderate in 2%) and moderate aortic regurgitation in 8%. Mitral valve prolapse (MVP) was present in 9% of patients without significant mitral regurgitation. There were no significant associations between structural or conduction abnormalities and age, degree of muscle weakness, or size of the 4q deletion. Conclusions: Both structural and conduction abnormalities can occur in FSHD. The most common abnormalities are benign (RBBB and MVP), but more significant cardiac involvement was also observed. The presence of cardiac abnormalities cannot be predicted from the severity of the neurological phenotype, nor from the genotype.

Electrophysiological Substrate in Patients with Barlow's Disease

Mitral valve prolapse (MVP) is the most common valvular heart disease, affecting 2-3% of the general population. Barlow's disease is a clinical syndrome characterised by MVP. Initially thought a benign condition, MVP is now recognised as a cause of sudden cardiac death and ventricular arrhythmias. The development of new imaging techniques has contributed recently to the identification of novel risk factors. Catheter ablation of ventricular arrhythmias in patients affected by MVP is traditionally considered challenging. In this review, the authors summarise the evidence on arrhythmogenesis in the context of MVP, along with risk stratification of sudden cardiac death and the available treatment options, including new catheter ablation techniques.

The current diagnosis and treatment of high-risk patients with chronic primary and secondary mitral valve regurgitation

Mitral valve regurgitation (MR) is due primarily to either primary degeneration of the mitral valve with Barlow's or fibroelastic disease or is secondary to ischemic or nonischemic cardiomyopathies. Echocardiography is essential to assess MR etiology and severity, the remodeling of cardiac chambers and to characterize longitudinal chamber changes to determine optimal therapies. Surgery is recommended for severe primary MR if persistent symptoms are present or if left ventricle dysfunction is present with an EF <60% or a left ventricle end-systolic diameter ≥40 mm. For secondary MR, therapy of heart failure with vasodilators and diuretics improves forward cardiac output. Coronary artery bypass grafts (CABG) or percutaneous coronary intervention (PCI) should be considered for severe MR due to ischemia. This review summarizes the pathophysiology, the characteristics, the management and the different interventions for high risk patients with chronic primary and secondary MR.

Aneurysmal and obstructive lesions of the left ventricular outflow: evaluation on multidetector computed tomography angiography

The left ventricular outflow is an anatomically complex region situated between the anterior leaflet of the mitral valve and the left ventricular aspect of the muscular and membranous interventricular septum. It gives rise to the aorta, provides support to the aortic valvular cusps, and houses important components of the conduction system. The left ventricular outflow handles high pressures and pressure variations and is subsequently affected by a variety of aetio-pathological conditions. Diseases involving the left ventricular outflow can be intraluminal, mural, or extramural, and the consequent complications of the lesions can be local, loco-regional, or even systemic. Appropriate evaluation requires comprehensive multimodality imaging with each modality contributing to assessment of different aspects of diagnosis, lesion characterization, local extension, prognostication for systemic complications and mortality, and the decision for the approach and type of intervention and aggressive follow-up in case non-interventional management is decided. In this review, we briefly describe the relevant anatomy and the gamut of structural abnormalities pertaining to the left ventricular outflow on multidetector computed tomography angiography.

DZIP1 regulates mammalian cardiac valve development through a Cby1-β-catenin mechanism

Background

Mitral valve prolapse (MVP) is a common and progressive cardiovascular disease with developmental origins. How developmental errors contribute to disease pathogenesis are not well understood.

Results

A multimeric complex was identified that consists of the MVP gene Dzip1, Cby1, and β‐catenin. Co‐expression during valve development revealed overlap at the basal body of the primary cilia. Biochemical studies revealed a DZIP1 peptide required for stabilization of the complex and suppression of β‐catenin activities. Decoy peptides generated against this interaction motif altered nuclear vs cytosolic levels of β‐catenin with effects on transcriptional activity. A mutation within this domain was identified in a family with inherited non‐syndromic MVP. This novel mutation and our previously identified DZIP1^S24R variant resulted in reduced DZIP1 and CBY1 stability and increased β‐catenin activities. The β‐catenin target gene, MMP2 was up‐regulated in the Dzip1^S14R/+ valves and correlated with loss of collagenous ECM matrix and myxomatous phenotype.

Conclusion

Dzip1 functions to restrain β‐catenin signaling through a CBY1 linker during cardiac development. Loss of these interactions results in increased nuclear β‐catenin/Lef1 and excess MMP2 production, which correlates with developmental and postnatal changes in ECM and generation of a myxomatous phenotype.

Mitral valve diseases: Pathophysiology and interventions

Valvular heart disease is common and increasingly prevalent among the elderly. The end result of valvular pathologies is cardiac failure and can lead to sudden death; thus, diagnosis and interventions are very important in the early stages of these diseases. The usual treatment methods of mitral regurgitation include percutaneous mitral valve repair, mitral valve replacement and minimally invasive surgery, whereas the treatment methods of mitral stenosis include percutaneous transluminal mitral commissurotomy and mitral commissurotomy as well as open surgical repair. Nonetheless, ongoing clinical trials are a clear indicator that the management of valve diseases is ever evolving. The focus of this paper is on the various pathologies of the mitral valve, their etiology and clinical management, offering a comprehensive view of mitral valve diseases.

Arrhythmic Mitral Valve Prolapse: Introducing an Era of Multimodality Imaging-Based Diagnosis and Risk Stratification

Mitral valve prolapse is a common cardiac condition, with an estimated prevalence between 1% and 3%. Most patients have a benign course, but ever since its initial description mitral valve prolapse has been associated to sudden cardiac death. Although the causal relationship between mitral valve prolapse and sudden cardiac death has never been clearly demonstrated, different factors have been implicated in arrhythmogenesis in patients with mitral valve prolapse. In this work, we offer a comprehensive overview of the etiology and the genetic background, epidemiology, pathophysiology, and we focus on the state-of-the-art imaging-based diagnosis of mitral valve prolapse. Going beyond the classical, well-described clinical factors, such as young age, female gender and auscultatory findings, we investigate multimodality imaging features, such as alterations of anatomy and function of the mitral valve and its leaflets, the structural and contractile anomalies of the myocardium, all of which have been associated to sudden cardiac death.

Neurologic complications of nonrheumatic valvular heart disease

Valvular heart disease (VHD) is frequently associated with neurologic complications. Cerebral embolism is the most common, since thrombus formation results from the abnormalities in the valvular surfaces and the anatomic and physiologic changes associated with valve dysfunction, including atrial or ventricular enlargement, intracardiac thrombi, and cardiac dysrhythmias. Prosthetic heart valves, particularly mechanical valves, are very thrombogenic, which explains the high risk of thromboembolism and the need for long-term anticoagulation. Transcatheter aortic valve replacement (TAVR) has emerged as a nonoperative alternative to surgical aortic valve replacement for patients with intermediate or high surgical risk, and the procedure also has a risk of cerebral ischemia. In addition, anticoagulation, the mainstay of treatment to prevent cerebral embolism, has known potential for hemorrhagic complications. The emergence of new oral anticoagulants with similar effectiveness to warfarin and a better safety profile has facilitated the management of patients with atrial fibrillation. However, their application in patients with mechanical heart valves is still evolving. The prevention and management of these complications requires an understanding of their natural history to balance the risks posed by valvular heart disease, as well as the risks and benefits associated with the treatment.

Antemortem and Post-Mortem Characteristics of Lethal Mitral Valve Prolapse Among All Countywide Sudden Deaths

OBJECTIVES

The goal of this study was to investigate the characteristics of mitral valve prolapse (MVP) in a post-mortem study of consecutive sudden cardiac deaths (SCDs) in subjects up to 90 years of age.

BACKGROUND

Up to 2.3% of subjects with MVPs experience SCD, but by convention SCD is rarely confirmed by autopsy. In a post-mortem study of persons <40 years of age, 7% of SCDs were caused by MVP; bileaflet involvement, mitral annular disjunction (MAD), and replacement fibrosis were common.

METHODS

In the San Francisco POST SCD (Postmortem Systematic Investigation of Sudden Cardiac Death) study, autopsies have been performed on >1,000 consecutive World Health Organization-defined (presumed) cases of SCD in subjects aged 18 to 90 years since 2011; a total of 603 were adjudicated. Autopsy-defined sudden arrhythmic death (SAD) required absence of nonarrhythmic cause; MVP diagnosis required leaflet billowing. One hundred antemortem echocardiograms were revised to identify additional MVPs missed on autopsy.

RESULTS

Among the 603 presumed SCDs, 339 (56%) were autopsy-defined SADs, with MVP identified in 7 (1%). Six additional MVPs were identified by review of echocardiograms, for a prevalence of at least 2% among 603 presumed SCDs and 4% among 339 SADs (vs. 264 non-SADs; p = 0.02). All 6 additional MVPs had monoleaflet rather than bileaflet involvement and mild mitral regurgitation, ruling out hemodynamic cause. Less than one-half had MAD with replacement fibrosis, but all had multisite interstitial fibrosis.

CONCLUSIONS

In a countywide post-mortem study of all adult cases of SCD, MVP prevalence was at least 4% of SADs, but one-half were missed on autopsy. Monoleaflet MVP was often underdiagnosed post-mortem. Compared with young cases of SCD, lethal MVP in older cases of SCD did not consistently have bileaflet anatomy, replacement fibrosis, or MAD.

Putative Circulating MicroRNAs Are Able to Identify Patients with Mitral Valve Prolapse and Severe Regurgitation

Mitral valve prolapse (MVP) associated with severe mitral regurgitation is a debilitating disease with no pharmacological therapies available. MicroRNAs (miRNA) represent an emerging class of circulating biomarkers that have never been evaluated in MVP human plasma. Our aim was to identify a possible miRNA signature that is able to discriminate MVP patients from healthy subjects (CTRL) and to shed light on the putative altered molecular pathways in MVP. We evaluated a plasma miRNA profile using Human MicroRNA Card A followed by real-time PCR validations. In addition, to assess the discriminative power of selected miRNAs, we implemented a machine learning analysis. MiRNA profiling and validations revealed that miR-140-3p, 150-5p, 210-3p, 451a, and 487a-3p were significantly upregulated in MVP, while miR-223-3p, 323a-3p, 340-5p, and 361-5p were significantly downregulated in MVP compared to CTRL (p ≤ 0.01). Functional analysis identified several biological processes possible linked to MVP. In addition, machine learning analysis correctly classified MVP patients from CTRL with high accuracy (0.93) and an area under the receiving operator characteristic curve (AUC) of 0.97. To the best of our knowledge, this is the first study performed on human plasma, showing a strong association between miRNAs and MVP. Thus, a circulating molecular signature could be used as a first-line, fast, and cheap screening tool for MVP identification.

Cardiac Imaging for Risk Assessment of Malignant Ventricular Arrhythmias in Patients With Mitral Valve Prolapse

Recent studies have described the occurrence of complex ventricular arrhythmias and sudden cardiac death among patients with mitral valve prolapse (MVP). The reported incidence rate of sudden cardiac death or ventricular tachycardia is about 1–1.5% among patients with MVP. Various imaging markers have been associated with this increased risk, including mitral annular disjunction, replacement fibrosis by late gadolinium enhancement, and mechanical dispersion. In this review, we briefly discuss how multimodality cardiac imaging can be applied to identify MVP patients with high risk of sudden cardiac death and complex ventricular arrhythmias.

Prevalence and characteristics of mitral valve prolapse in military young adults in Taiwan of the CHIEF Heart Study

The prevalence of mitral valve prolapse (MVP) among middle- and older-aged individuals is estimated to be 2–4% in Western countries. However, few studies have been conducted among Asian individuals and young adults. This study included a sample of 2442 consecutive military adults aged 18–39 years in Hualien, Taiwan. MVP was defined as displacement of the anterior or posterior leaflet of the mitral valve to the mid portion of the annular hinge point > 2 mm in the parasternal long-axis view of echocardiography. Cardiac chamber size and wall thickness were measured based on the latest criteria of the American Society of Echocardiography. The clinical features of participants with MVP and those without MVP were compared using a two-sample t test, and the cardiac structures were compared using analysis of covariance with adjustment for body surface area (BSA). Eighty-two participants were diagnosed with MVP, and the prevalence was 3.36% in the overall population. Compared with those without MVP, participants with MVP had a lower body mass index (kg/m²) (24.89 ± 3.70 vs. 23.91 ± 3.45, p = 0.02) and higher prevalence of somatic symptoms related to exercise (11.0% vs. 4.9%, p = 0.02) and systolic click in auscultation (18.3% vs. 0.6%, p < 0.01). In addition, participants with MVP had greater left ventricular mass (gm) and smaller right ventricular wall thickness (mm) and dimensions (mm) indexed by BSA than those without MVP (149.12 ± 35.76 vs. 155.38 ± 36.26; 4.66 ± 0.63 vs. 4.40 ± 0.68; 26.57 ± 3.99 vs. 25.41 ± 4.35, respectively, all p-values < 0.01). In conclusion, the prevalence and clinical features of MVP in military young adults in Taiwan were in line with those in Western countries. Whether the novel MVP phenotype found in this study has any pathological meaning needs further investigation.

Echocardiographic screening for mitral valve prolapse in Turkish school children

We determined the frequency of mitral valve prolapse (MVP) in healthy Turkish school children using the current echocardiographic diagnostic criteria. This epidemiological survey was performed on 2550 school children. All children were screened with echocardiography and the family of children with MVP were also screened. The prolapse of mitral leaflets into left atrium ≥ 2 mm in parasternal long-axis view was used as diagnostic criteria. MVP was classified as classical or non-classical according to anterior mitral leaflet thickness. The thickness of anterior mitral leaflet, the extent of prolapse, and the presence of mitral regurgitation were evaluated. The children were also questioned about the associated symptoms. The prevalence of MVP was 1.25% in children with a mean age of 11.1 ± 2.9 years. The prevalence was 0.9%, 1.2%, and 1.6% in 5-9 years, 10-13 years, and 14-18 years of age, respectively. 43.7% of the cases were classical MVP. The frequency of auscultation findings was 34.3%. 11/34 children had mitral regurgitation. There was no statistically significant difference between classical MVP and non-classical MVP in terms of mitral regurgitation, physical examination findings, and symptoms. Anxiety (37.5%) was the most common symptom. The frequency of MVP in the first-degree relatives of children with MVP was 11/84 (13.1%). Most patients with MVP don't have auscultation findings and symptoms, therefore echocardiography is an important tool in the diagnosis of MVP. It is also reasonable to screen first degree relatives of MVP patients with echocardiography.

Radiofrequency ablation alters the microstructural organization of healthy and enzymatically digested porcine mitral valves

BACKGROUND

Myxomatous mitral valve degeneration is a common cause of mitral regurgitation and is often associated with mitral valve prolapse. With no known targets to pharmacologically treat mitral valve prolapse, surgery is often the only treatment option. Recently, radiofrequency ablation has been proposed as a percutaneous alternative to surgical resection for the reduction of mitral valve leaflet area.

OBJECTIVE

Using an in vitro model of porcine mitral valve anterior leaflet enlargement following enzymatic digestion, we sought to investigate mechanisms by which radiofrequency ablation alters the geometry, microstructural organization, and mechanical properties of healthy and digested leaflets.

METHODS

Paired measurements before and after ablation revealed the impact of radiofrequency ablation on leaflet properties. Multiphoton imaging was used to characterize changes in the structure and organization of the valvular extracellular matrix; planar biaxial mechanical testing and constitutive modeling were used to estimate mechanical properties of healthy and digested leaflets.

RESULTS

Enzymatic digestion increased leaflet area and thickness to a similar extent as clinical mitral valve disease. Radiofrequency ablation altered extracellular matrix alignment and reduced the area of digested leaflets to that of control. Additionally, enzymatic digestion resulted in fiber alignment and reorientation toward the radial direction, causing increased forces during ablation and a structural stiffening which was improved by radiofrequency ablation.

CONCLUSION

Radiofrequency ablation induces radial extracellular matrix alignment and effectively reduces the area of enlarged mitral valve leaflets. Hence, this technique may be a therapeutic approach for myxomatous mitral valve disease and is thus an avenue for future study.

Systematic quantification of histologic ventricular fibrosis in isolated mitral valve prolapse and sudden cardiac death

BACKGROUND

Cardiac fibrosis in mitral valve prolapse (MVP) is implicated in the development of sudden cardiac death (SCD); however, the pattern remains poorly characterized.

OBJECTIVE

The purpose of this study was to systematically quantify left and right ventricular fibrosis in individuals with isolated MVP and SCD (iMVP-SCD), whereby other potential causes of death are excluded, compared to a control cohort.

METHODS

Individuals with iMVP-SCD were identified from the Victorian Institute of Forensic Medicine, Australia, and matched for age, sex, and body mass index to control cases with noncardiac death. Cardiac tissue sections were analyzed to determine collagen deposition in the left ventricular free wall (anterior, lateral, and posterior portions), interventricular septum, and right ventricle. Within the iMVP-SCD cases, the endocardial-to-epicardial distribution of fibrosis within the left ventricle was specifically characterized.

RESULTS

Seventeen cases with iMVP-SCD were matched 1:1 with 17 controls, yielding 149 samples and 1788 histologic regions. The iMVP-SCD group had increased left ventricular (anterior, lateral, and posterior; all P <.001) and interventricular septum fibrosis (P <.001), but similar amounts of right ventricular fibrosis (P = .62) compared to controls. In iMVP-SCD, left ventricular fibrosis was significantly higher in the lateral and posterior walls compared to the anterior wall and interventricular septum (all P <.001). Within the lateral and posterior walls, iMVP-SCD cases had a significant endocardial-to-epicardial gradient of cardiac fibrosis (P <.01) similar to other known conditions that cause cardiac remodeling.

CONCLUSION

Our study indicates that nonuniform left ventricular remodeling with both localized and generalized left ventricular fibrosis is important in the pathogenesis of SCD in individuals with MVP.

Global Burden of Cardiovascular Diseases and Risk Factors, 1990-2019: Update From the GBD 2019 Study

Cardiovascular diseases (CVDs), principally ischemic heart disease (IHD) and stroke, are the leading cause of global mortality and a major contributor to disability. This paper reviews the magnitude of total CVD burden, including 13 underlying causes of cardiovascular death and 9 related risk factors, using estimates from the Global Burden of Disease (GBD) Study 2019. GBD, an ongoing multinational collaboration to provide comparable and consistent estimates of population health over time, used all available population-level data sources on incidence, prevalence, case fatality, mortality, and health risks to produce estimates for 204 countries and territories from 1990 to 2019. Prevalent cases of total CVD nearly doubled from 271 million (95% uncertainty interval [UI]: 257 to 285 million) in 1990 to 523 million (95% UI: 497 to 550 million) in 2019, and the number of CVD deaths steadily increased from 12.1 million (95% UI:11.4 to 12.6 million) in 1990, reaching 18.6 million (95% UI: 17.1 to 19.7 million) in 2019. The global trends for disability-adjusted life years (DALYs) and years of life lost also increased significantly, and years lived with disability doubled from 17.7 million (95% UI: 12.9 to 22.5 million) to 34.4 million (95% UI:24.9 to 43.6 million) over that period. The total number of DALYs due to IHD has risen steadily since 1990, reaching 182 million (95% UI: 170 to 194 million) DALYs, 9.14 million (95% UI: 8.40 to 9.74 million) deaths in the year 2019, and 197 million (95% UI: 178 to 220 million) prevalent cases of IHD in 2019. The total number of DALYs due to stroke has risen steadily since 1990, reaching 143 million (95% UI: 133 to 153 million) DALYs, 6.55 million (95% UI: 6.00 to 7.02 million) deaths in the year 2019, and 101 million (95% UI: 93.2 to 111 million) prevalent cases of stroke in 2019. Cardiovascular diseases remain the leading cause of disease burden in the world. CVD burden continues its decades-long rise for almost all countries outside high-income countries, and alarmingly, the age-standardized rate of CVD has begun to rise in some locations where it was previously declining in high-income countries. There is an urgent need to focus on implementing existing cost-effective policies and interventions if the world is to meet the targets for Sustainable Development Goal 3 and achieve a 30% reduction in premature mortality due to noncommunicable diseases.

Asymptomatic degenerative mitral regurgitation repair: Validating guidelines for early intervention

INTRODUCTION

Mitral repair for asymptomatic (New York Heart Association [NYHA] class I) degenerative mitral regurgitation (MR) is supported by the guidelines, but is not performed often. We sought to determine outcomes for asymptomatic patients when compared with those with symptoms.

METHODS

Between 2004 and 2018, 1027 patients underwent mitral replacement (22) or repair with or without other cardiac surgery (1005), the latter being grouped by NYHA class: I (n = 470; 47%), II (n = 408; 40%), or III/IV (n = 127; 13%). Statistical analyses included propensity score matching and weighting, and multistate models.

RESULTS

The proportion of patients designated as NYHA class I undergoing surgery increased steadily during this period (P < .001). Overall, 30-day mortality was 0.4%, and zero for patients designated NYHA class I. Unadjusted 10-year survival was significantly greater in patients designated NYHA class I compared with II and III/IV (P < .001). Freedom from reoperation at 10 years was 99.8% overall, and 100% for patients designated NYHA class I. In patients designated as NYHA class I, predischarge and 10-year moderate MR were 0.7% and 20.1%, whereas more than moderate was zero and 0.6%. Preoperative ejection fraction less than 60% was associated with late mortality (P = .025). After covariate-adjustments, freedom from MR and tricuspid regurgitation were not statistically significantly different by NYHA class. However, overall survival was significantly worse in patients with NYHA class III/IV, compared with class II.

CONCLUSIONS

Mitral repair in asymptomatic patients is safe and durable. Careful monitoring until class II symptoms is appropriate. However, repair before ejection fraction decreases below 60% is important for late overall survival.

Phonocardiography-based mitral valve prolapse detection with using fractional fourier transform

Mitral Valve Prolapse (MVP) is a common condition among people, which is often benign and does not need any serious treatment. However, this doesn't mean that MVP can't cause any problems. In malignant conditions, MVP can cause mitral failure and also heart failure. Early diagnosis of MVP is significantly important to control and reduce its complications. Since the phonocardiogram signal provides useful information about heart valves function, it can be used for MVP detection. To detect MVP, the signal was denoised and segmented into heart cycles and constant three-second pieces in the first and second approaches, respectively. Next, based on the Fractional Fourier Transform (FrFT), the desired features were extracted. Then, the extracted features were windowed by a Moving Logarithmic Median Window (MLMW) and optimum features were selected using Mahalanobis, Bhattacharyya, Canberra, and Minkowski distance criteria. Finally, using the selected features, classification was performed by using the K-Nearest Neighbor (KNN) and the Suppor Vector Machine (SVM) classifiers to find out whether a segment is prolapsed. The best results of the experiment on the collected database contain 15 prolapsed and 6 non-prolapsed subjects using the A-test method show 96.25 ± 2.43 accuracy, 98.5 ± 3.37 sensitivity, 94.0 ± 5.16 specificity, 96.0 ± 3.44 precision, 92.5 ± 4.86 kappa, and 96.6 ± 2.34 f-score with the SVM classifier.

Report of a rare case of congenital mitral valve prolapse with chronic kidney disease--reconsidered genotype-phenotypic correlations

Background

Mitral valve prolapse (MVP) is a common cardiovascular disease defined as a late systolic click or mitral valve lobes that move up into the left atrium during ventricular systole, with or without mitral insufficiency. Dachsous catherin‐related 1 (DCHS1) is one of the two known pathogenic genes associated with MVP. However, there is little information about the renal dysfunction caused by MVP and DCHS1 mutations.

Methods

We analyzed the genetic etiology in a rare case of 9‐year‐old boy affected by chronic renal failure with MVP. Subsequently, we constructed stable cell lines overexpressing wild‐type DCHS1 or mutant DCHS1 (c.8309G>A, p.R2770Q) to evaluate the influence of the DCHS1 mutation on the proliferation, apoptosis, and autophagy.

Results

Complete exome sequencing and pedigree verification revealed a mutation p.R2770Q (c.8309G>A) in exon 21 of the DCHS1 gene carried by the patient, which may affect the DNA binding. No such mutation was detected in his parents, indicating that this was a new mutation. Potential functional impact of sequence variants was predicted using in silico prediction programs including SIFT, Polyphen2, and Condel. This variant was determined to be a pathogenic mutation that has not been reported elsewhere. Subsequently, we used a stable DCHS1 gene‐mutated HK‐2 cell line to analyse proliferation, apoptosis, and autophagy, showed that kidney volume decreased with increasing cell death associated with a reduced proliferation.

Conclusions

Our analysis revealed a heterozygous variation of DCHS1 in a child with MVP. Our observations highlight previously unrecognized phenotypes of the currently recognized MVP genotype, including distinct chronic renal failure.

[Mitral prolapse and sudden death. A case report]

The association between the mitral valve prolapse and the sudden Cardiac Death remains controversial, the high prevalence of this valvulopathy contrasting with the low incidence of sudden death in this population. We report the case of a 54-year-old woman admitted for a sudden cardiac death, revealing a bi-prolapse with low-grade leakage, leading to the implantation of a subcutaneous automatic defibrillator. Combined echocardiography and cardiac MRI can identify the mitral annular disjunction, the rolling motion of the posterior face of the mitral annulus towards the myocardium, and the myocardial fibrosis of the inferolateral wall induced by streching forces of the sub valvular apparatus, that may lead to ventricular arrhythmias. More than the conventional clinical parameters (young woman, ventricular premature beats with a right bundle branch block morphology, mitral bi-prolapse), mitral annular disjunction and myocardial fibrosis are to be considered as powerful markers of the rhythmic risk of mitral prolapse and must be systematically sought and integrated into the prognostic evaluation of these patients. In the absence of randomised trials, therapeutic management is difficult especially in primary prevention, and needs Heart Team advice.

Influence of chest conformation on myocardial strain parameters in healthy subjects with mitral valve prolapse

Chest shape might affect myocardial strain parameters. However, the relationship between myocardial strain parameters and chest conformation has not been previously investigated in subjects with mitral valve prolapse (MVP). Between April 2019 and May 2020, 60 healthy subjects (50.1 ± 8.6 year/old, 46.6% females) with MVP and mild-to-moderate mitral regurgitation, and 60 controls matched by age, sex, and cardiovascular risk factors were consecutively studied. Participants underwent modified Haller index (MHI) assessment (ratio of chest transverse diameter over the distance between sternum and spine), and transthoracic echocardiography implemented with 2D-speckle tracking analysis. MHI was significantly greater in MVP group than controls (2.6 ± 0.35 vs 2.1 ± 0.23, p < 0.0001). Left ventricular (LV) ejection fraction was similar in MVP and controls (63.5 ± 3.7% vs 64.3 ± 3.9%, p = 0.25). LV regional and global longitudinal (GLS), circumferential (GCS) and radial strain (GRS) parameters and LV peak twist were all significantly lower in MVP compared to controls (all p < 0.0001). MVP subjects with a tight chest (MHI > 2.5, n = 30), and those with MHI ≤ 2.5 (n = 30) were then separately analyzed. A significant impairment in myocardial strain parameters and LV peak twist was documented in MVP subjects with MHI > 2.5, but not in those with MHI ≤ 2.5. MHI showed a strong inverse correlation with LV-GLS (r = - 0.85), GCS (r = - 0.84), GRS (r = - 0.84) and LV peak twist (r = - 0.94). In MVP subjects, impairment of myocardial strain parameters is not due to intrinsic reduction of cardiac contractility function, but it appears to be related to the degree of chest deformity.

Resolving the Disproportionate Left Ventricular Enlargement in Mitral Valve Prolapse Due to Barlow Disease: Insights From Cardiovascular Magnetic Resonance

OBJECTIVES

This study hypothesized that left ventricular (LV) enlargement in Barlow disease can be explained by accounting for the total volume load that consists of transvalvular mitral regurgitation (MR) and the prolapse volume.

BACKGROUND

Barlow disease is characterized by long prolapsing mitral leaflets that can harbor a significant amount of blood-the prolapse volume-at end-systole. The LV in Barlow disease can be disproportionately enlarged relative to MR severity, leading to speculation of Barlow cardiomyopathy.

METHODS

Cardiac magnetic resonance (CMR) was used to compare MR, prolapse volume, and heart chambers remodeling in patients with Barlow disease (bileaflet prolapse [BLP]) and in single leaflet prolapse (SLP).

RESULTS

A total of 157 patients (81 with BLP, 76 with SLP) were included. Patients with SLP were older and more had hypertension. Patients with BLP had more heart failure. Indexed LV end-diastolic volume was larger in BLP despite similar transvalvular MR. However, the prolapse volume was larger in BLP, which led to larger total volume load compared with SLP. Increasing tertiles of prolapse volume and MR both led to an incremental increase in LV end-diastolic volume in BLP. Using the total volume load improved the correlation with indexed LV end-diastolic volume in the BLP group, which closely matched that of SLP. A multivariable model that incorporated the prolapse volume explained left heart chamber enlargement better than a MR-based model, independent of prolapse category.

CONCLUSIONS

The prolapse volume is part of the total volume load exerted on the LV during the cardiac cycle and could help explain the disproportionate LV enlargement relative to MR severity noted in Barlow disease.

Stress-induced remodelling of the mitral valve: a model for leaflet thickening and superimposed tissue formation in mitral valve disease

AIMS

In mitral valve prolapse (MVP), leaflet thickening has recently been suggested to be due, in addition to a myxomatous degeneration, to the presence of a superimposed tissue (SIT), defined as an additional fibrous layer on top of the original leaflet. The mechanisms of SIT formation are currently unknown. We hypothesized that SIT formation would result from excessive leaflet stress and we used a unique ex vivo model to assess the correlation between leaflet remodelling and the type and location of mechanical stress and to elucidate the mechanisms underlying SIT formation.

METHODS AND RESULTS

Human diseased mitral valves (MVs; n = 21) were histologically analysed for SIT formation and original leaflet thickening. The SIT comprised of various compositions of extracellular matrix and could reach more than 50% of total leaflet thickness. Original leaflet and SIT thickness did not show significant correlation (r = -0.27, P = 0.23), suggesting different regulatory mechanisms. To study the role of the mechanical environment on MV remodelling, mouse MV were cultured in their natural position in the heart and subjected to various haemodynamic conditions representing specific phases of the cardiac cycle and the MVP configuration. SIT formation was induced in the ex vivo model, mostly present on the atrial side, and clearly dependent on the duration, type, and extent of mechanical stress. Specific stainings and lineage tracing experiments showed that SIT comprises of macrophages and myofibroblasts and is associated with the activation of the transforming growth factor-beta and bone morphogenetic protein signalling pathways. Migration of valvular interstitial cells and macrophages through breakages of the endothelial cell lining contributed to SIT formation.

CONCLUSIONS

Mechanical stresses induce specific cellular and molecular changes in the MV that result in SIT formation. These observations provide the first insights in the mechanism of SIT formation and represent an initial step to identify potential novel and early treatment for MVP.

A Genomic Study of Myxomatous Mitral Valve Disease in Cavalier King Charles Spaniels

Cavalier King Charles spaniels (CKCSs) show the earliest onset and the highest incidence of myxomatous mitral valve disease (MMVD). Previous studies have suggested a polygenic inheritance of the disease in this breed and revealed an association with regions on canine chromosomes 13 and 14. Following clinical and echocardiographic examinations, 33 not-directly-related CKCSs were selected and classified as cases (n = 16) if MMVD was present before 5 years of age or as controls (n = 17) if no or very mild MMVD was present after 5 years of age. DNA was extracted from whole blood and genotyped with a Canine 230K SNP BeadChip instrument. Cases and controls were compared with three complementary genomic analyses (Wright's fixation index-F_ST, cross-population extended haplotype homozygosity-XP-EHH, and runs of homozygosity-ROH) to identify differences in terms of heterozygosity and regions of homozygosity. The top 1% single-nucleotide polymorphisms (SNPs) were selected and mapped, and the genes were thoroughly investigated. Ten consensus genes were found localized on chromosomes 3-11-14-19, partially confirming previous studies. The HEPACAM2, CDK6, and FAH genes, related to the transforming growth factor β (TGF-β) pathway and heart development, also emerged in the ROH analysis. In conclusion, this work expands the knowledge of the genetic basis of MMVD by identifying genes involved in the early onset of MMVD in CKCSs.

Randomized, Controlled Trial Comparing Mitral Valve Repair With Leaflet Resection Versus Leaflet Preservation on Functional Mitral Stenosis

Background:

Equipoise exists between the use of leaflet resection and preservation for surgical repair of mitral regurgitation caused by prolapse. We therefore performed a randomized, controlled trial comparing these 2 techniques, particularly in regard to functional mitral stenosis.

Methods:

One hundred four patients with degenerative mitral regurgitation surgically amenable to either leaflet resection or preservation were randomized at 7 specialized cardiac surgical centers. Exclusion criteria included anterior leaflet or commissural prolapse, as well as a mixed cause for mitral valve disease. Using previous data, we determined that a sample size of 88 subjects would provide 90% power to detect a 5–mm Hg difference in mean mitral valve gradient at peak exercise, assuming an SD of 6.7 mm with a 2-sided test with α=5% and 10% patient attrition. The primary end point was the mean mitral gradient at peak exercise 12 months after repair.

Results:

Patient age, proportion who were female, and Society of Thoracic Surgeons risk score were 63.9±10.4 years, 19%, and 1.4±2.8% for those who were assigned to leaflet resection (n=54), and 66.3±10.8 years, 16%, and 1.9±2.6% for those who underwent leaflet preservation (n=50). There were no perioperative deaths or conversions to replacement. At 12 months, moderate mitral regurgitation was observed in 3 subjects in the leaflet resection group and 2 in the leaflet preservation group. The mean transmitral gradient at 12 months during peak exercise was 9.1±5.2 mm Hg after leaflet resection and 8.3±3.3 mm Hg after leaflet preservation ( P =0.43). The participants had similar resting peak (8.3±4.4 mm Hg versus 8.4±2.6 mm Hg; P =0.96) and mean resting (3.2±1.9 mm Hg versus 3.1±1.1 mm Hg; P =0.67) mitral gradients after leaflet resection and leaflet preservation, respectively. The 6-minute walking distance was 451±147 m for those in the leaflet resection versus 481±95 m for the leaflet preservation group ( P =0.27).

Conclusions:

In this adequately powered randomized trial, repair of mitral prolapse with either leaflet resection or leaflet preservation was associated with similar transmitral gradients at peak exercise at 12 months postoperatively. These data do not support the hypothesis that a strategy of leaflet resection (versus preservation) is associated with a risk of functional mitral stenosis.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier NCT02552771.

Cardiac magnetic resonance in arrhythmogenic cardiomyopathies

Over the past few years, the approach to the 'arrhythmic patient' has profoundly changed. An early clinical presentation of arrhythmia is often accompanied by non-specific symptoms and followed by inconclusive electrocardiographic findings. In this scenario, cardiac magnetic resonance (CMR) has been established as a clinical tool of fundamental importance for a correct prognostic stratification of the arrhythmic patient. This technique provides a high-spatial-resolution tomographic evaluation of the heart, which allows studying accurately the ventricular volumes, identifying even segmental kinetic anomalies and properly detecting diffuse or focal tissue alterations through an excellent tissue characterization, while depicting different patterns of fibrosis distribution, myocardial edema or fatty substitution. Through these capabilities, CMR has a pivotal role for the adequate management of the arrhythmic patient, allowing the identification of those phenotypic manifestations characteristic of structural heart diseases. Therefore, CMR provides valuable information to reclassify the patient within the wide spectrum of potentially arrhythmogenic heart diseases, the definition of which remains the major determinants for both an adequate treatment and a poor prognosis. The purpose of this review study was to focus on the role of CMR in the evaluation of the main cardiac clinical entities associated with arrhythmogenic phenomena and to present a brief debate on the main pathophysiological mechanisms involved in the arrhythmogenesis process.

E3 Ubiquitin ligase NEDD4 family‑regulatory network in cardiovascular disease

Protein ubiquitination represents a critical modification occurring after translation. E3 ligase catalyzes the covalent binding of ubiquitin to the protein substrate, which could be degraded. Ubiquitination as an important protein post-translational modification is closely related to cardiovascular disease. The NEDD4 family, belonging to HECT class of E3 ubiquitin ligases can recognize different substrate proteins, including PTEN, ENaC, Nav1.5, SMAD2, PARP1, Septin4, ALK1, SERCA2a, TGFβR3 and so on, via the WW domain to catalyze ubiquitination, thus participating in multiple cardiovascular-related disease such as hypertension, arrhythmia, myocardial infarction, heart failure, cardiotoxicity, cardiac hypertrophy, myocardial fibrosis, cardiac remodeling, atherosclerosis, pulmonary hypertension and heart valve disease. However, there is currently no review comprehensively clarifying the important role of NEDD4 family proteins in the cardiovascular system. Therefore, the present review summarized recent studies about NEDD4 family members in cardiovascular disease, providing novel insights into the prevention and treatment of cardiovascular disease. In addition, assessing transgenic animals and performing gene silencing would further identify the ubiquitination targets of NEDD4. NEDD4 quantification in clinical samples would also constitute an important method for determining NEDD4 significance in cardiovascular disease.

Risk of Mitral Valve Prolapse in Patients with Keratoconus in Taiwan: A Population-Based Cohort Study

This retrospective, nationwide, matched-cohort study included 4488 new-onset keratoconus (KCN) patients, ≥12 years old, recruited between 2004 and 2011 from the Taiwan National Health Insurance Research Database. The control group included 26,928 non-KCN patients selected from the Taiwan Longitudinal Health Insurance Database 2000. Information for each patient was collected and tracked from the index date until December 2013. The incidence rate of mitral valve prolapse (MVP) was 1.77 times (95% confidence interval (CI) = 1.09–2.88; p = 0.0206) higher in KCN patients ≥40 years old and 1.49 times (95% CI = 1.12–1.98; p = 0.0060) higher in female KCN patients than in controls. After using the Cox proportional hazard regression analysis to adjust for potential confounders, including hypertension, hyperlipidemia, and congestive heart failure, KCN maintained an independent risk factor, MVP being 1.77 times (adjusted hazard ratio (HR) = 1.77, 95% CI = 1.09–2.88) and 1.48 times (adjusted HR = 1.48, 95% CI = 1.11–1.97) more likely to develop in patients ≥40 years old and female patients in the study cohort, respectively. We found that KCN patients ≥40 years of age and female KCN patients have increased risks of MVP. Therefore, it is recommended that KCN patients should be alerted to MVP.

Smooth Muscle α-Actin Expression in Mitral Valve Interstitial Cells is Important for Mediating Extracellular Matrix Remodeling

Background: Mitral valve prolapse (MVP) affects 3–6% of the total population including those with connective tissue disorders. Treatment is limited, and patients commonly require surgery which can be impermanent and insuperable. Abnormal prolapse of mitral valve leaflets into the left atria is caused by disturbances to the composition and organization of the extracellular matrix (ECM), that weaken biomechanics. This process, known as myxomatous degeneration is characterized by an abnormal accumulation of proteoglycans, in addition to collagen fiber disruption and elastic fiber fragmentation. The underlying mechanisms that promote myxomatous degeneration to the point of biomechanical failure are unknown, but previous histological studies of end-stage diseased tissue have reported abnormal α-smooth muscle actin (SMA) in a subset of heart valve interstitial cells (VICs); however, the contribution of these abnormal cells to MVP pathogenesis has not been extensively examined. Methods: In vivo and in vitro approaches were used. Mice harboring a Fbn1^C1039G mutation mimic human Marfan Syndrome and develop MVP. Using these mice, temporal and spatial changes in SMA expression relative to myxomatous degeneration were examined using histological techniques. In parallel in vitro experiments, SMA expression was downregulated in primary porcine mitral VICs directly using siRNA, and indirectly using the actin depolymerizing agent Latrunculin A. In addition, the regulation of SMA in VICs by mechanical stiffness was explored relative to ECM remodeling. Results: We show, in mitral valves from Fbn1^C1039G/+ mice, that abnormal increases in SMA expression in VICs are evident during early postnatal stages of disease, prior to significant myxomatous degeneration as indicated at later stages by increased proteoglycans and collagen type I (Col1a1). Furthermore, abnormal SMA expression continues to increase during the course of pathogenesis and is localized to the mid belly region of the mitral valve leaflets from 10 weeks. Using an in vitro approach, we demonstrate that reduced SMA function by direct siRNA or indirect Latrunculin A treatment attenuates proteoglycan and Col1a1 expression in porcine mitral VICs. While upstream, we provide insights to show that SMA is regulated by mechanical tension in VICs to promote changes in ECM homeostasis. Conclusions: Together, our data show that in VICs, SMA, an actin binding protein, is important for mediating ECM remodeling associated with phenotypes observed in myxomatous degeneration, and its expression is regulated by mechanical tension. These novel insights could inform the development of future non-surgical therapeutics to halt the progression of mitral valve degeneration thereby avoiding end-stage prolapse.

Quantification of load-dependent changes in the collagen fiber architecture for the strut chordae tendineae-leaflet insertion of porcine atrioventricular heart valves

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 tissue's 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 valve's 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.

Mitral Valve Prolapse Patients with Less than Moderate Mitral Regurgitation Exhibit Early Cardiac Chamber Remodeling

BACKGROUND

Mild physiologic mitral regurgitation (MR) is common in normal individuals. Patients with primary MR due to mitral valve prolapse (MVP) may also exhibit less than moderate MR. We sought to determine whether MVP patients with less than moderate MR displayed early cardiac chamber remodeling or factors related to early remodeling and whether early remodeling predicted MR progression.

METHODS

Consecutive MVP patients with less than moderate MR by proximal isovelocity surface area-derived effective regurgitant orifice < 20 mm2 and regurgitant volume < 30 mL, were matched for age and sex with non-MVP patients (controls) having less than moderate MR. Patients with moderate or greater dysfunctional left- or right-sided valves and left ventricular ejection fraction < 50% were excluded. We evaluated left ventricle (LV) and left atrium (LA) remodeling parameters (LV end-diastolic and end-systolic indexed diameters, LA volume-index, and LV mass-index) as well as determinants of remodeling. The last available transthoracic echocardiography was reviewed to identify progression to moderate-severe MR or more.

RESULTS

A total of 253 MVP patients with less than moderate MR were matched to 344 controls (P for age and sex, ≥.18) with less than moderate MR. Patients with MVP (mean effective regurgitant orifice and regurgitant volume, 12 ± 4 mm2 and 18 ± 6 mL, respectively) had more premature ventricular contractions (PVCs), larger LV and LA remodeling parameters, and more mild-to-moderate MR (all P < .0001). Multivariate linear regression models showed that larger LV remodeling parameters were independently associated with MVP and female sex but not MR severity (all P < .0001). The LA volume index was independently associated with MVP, age, and E/e' (all P < .0001). The LV mass index was associated with MVP, age, and hypertension (all P ≤ .002). Presence of PVCs was associated with LV end-systolic diameter ≥ 40 mm and indexed ≥ 22 mm2 (P = .005). Among 323 (54%) patients having subsequent transthoracic echocardiography, 17 patients (all MVP) progressed to moderate-severe MR or more at a median of 4.3 (interquartile range, 1.7-6.4) years. Isolated posterior leaflet prolapse was the single factor associated with MR progression (adjusted hazard ratio, 2.70; 95% CI, 0.99-7.34; P = .048) after adjustment for MR severity. At a median of 5.9 (interquartile range, 4.6-7.2) years of follow-up, female sex and MVP (vs controls) were protective factors for mortality.

CONCLUSIONS

Patients with less than moderate MR due to MVP exhibit early LV and LA remodeling, which does not predict MR progression or mortality. Left ventricle remodeling is associated with MVP, female sex, and presence of PVCs. Early chamber remodeling associated with MVP may be the phenotypical expression of a genetically mediated process and is at least partially related to PVCs.

New synthetic mitral valve model for human prolapsed mitral valve reconstructive surgery for training

The training process of young surgeons is highly desirable in order for them to gain an understanding of the quality of care and patient safety required during cardiac surgeries, however, it may take a few years of practice in order for them to properly develop these skills. Artificial life-like platforms and models are extremely recommended for teaching hands-on and real-world practice in both junior and even experienced medical professionals and surgeons. Suitable and accessible training tools are of significant importance for simulating a particular surgery in order to provide practice opportunities for a specific surgical procedure. In this study, we focussed on the simulation of the human mitral valve prolapse reconstructive surgery. An innovative, artificial, biomimetic model was designed and fabricated made of Cryogel biomaterial developed in our lab that is suitable for the precise practice on the mitral valve prolapse model. The proposed model is mainly made up of polyvinyl alcohol (PVA) cryogel, which is designed to resemble the geometric and mechanical properties of a diseased (prolapse) mitral valve. We simulated the constructive prolapsed mitral valve surgery entirely on a synthetic platform. The platform was made available to four certified cardiac surgeon and there were unanimously very positive with no considerable differences in the procedural assessments between them. The proposed model has a similar appearance and texture to that of a diseased mitral valve and holds consistent mechanical properties to those of the real tissue. The offered technology may be used for other cardiothoracic reconstructive surgeries with high precision and consistency.

Arrhythmia insensitive rapid cardiac T1 mapping: comparison to modified look locker inversion recovery T1 mapping in mitral valve prolapse patients

We compare a saturation recovery arrhythmia insensitive rapid (AIR) T1 mapping technique which is less sensitive to heart rate and requires shorter breath-holds to modified Look-Locker inversion recovery (MOLLI) T1 mapping in patients with mitral valve prolapse. 55 patients underwent AIR and MOLLI at 1.5 T. AIR and MOLLI-derived blood and myocardial T1 values and extracellular volume (ECV) were measured by two independent readers. T1 values and ECV from both techniques and inter-reader agreement were compared with Lin's concordance correlation coefficient (LCC) and reduced major axis regression. T1 values were consistently overestimated for AIR compared to MOLLI and vice versa for ECV. In the mitral valve prolapse population, mean native and post contrast myocardial T1 value for MOLLI were 1000 ± 40 ms and 411.9 ± 44.2 ms respectively and 1090.6 ± 58.7 ms and 488.2 ± 45.7 ms for AIR. Mean native and post contrast blood T1 values for MOLLI were 1566.6 ± 72.3 ms and 276.6 ± 34.1 ms respectively versus 1657.2 ± 180.9 ms and 294.9 ± 35.6 ms for AIR. AIR underestimated ECV relative to MOLLI (23.5 ± 0.4% vs 27.7 ± 0.4%). We found excellent inter-reader agreement (LCC all > 0.94, p < 0.0001) for both AIR and MOLLI techniques as well as intra-reader reliability (LCC all > 0.97, p < 0.0001). AIR can be performed in patients with mitral valve prolapse with excellent inter and intra-reader agreement, with higher T1 values compared to MOLLI, in line with other saturation recovery techniques. A consistent T1 mapping technique should be used when performing serial imaging.

Cardiac involvement in classical or hypermobile Ehlers-Danlos syndrome is uncommon

PURPOSE

Cardiac-valvular and vascular Ehlers-Danlos syndrome (EDS) have significant cardiovascular issues. The prevalence and significance of such abnormalities in classical (cEDS) or hypermobile EDS (hEDS) remain unclear. We report the prevalence of cardiac abnormalities in patients with cEDS and hEDS.

METHODS

We identified 532 pediatric patients with potential EDS evaluated at our institution from January 2014 through April 2019 by retrospective chart review. Ninety-five patients (12 cEDS and 83 hEDS patients) met 2017 EDS diagnostic criteria and had an echocardiogram. One patient was excluded due to complex congenital heart disease, and two were excluded due to lack of images. We reviewed echocardiograms for all structural abnormalities.

RESULTS

Of these 95 patients, 1 had mild aortic root dilation, and 1 had mild ascending aorta dilation in the setting of a bicuspid aortic valve. Eleven patients (11.6%) had a cardiac valve abnormality, all of which were trivial to mild. None of the patients required cardiac intervention.

CONCLUSION

Our results demonstrate that aortic dilation and valvular anomalies are uncommon in cEDS or hEDS patients. Given the lack of evidence, we do not recommend echocardiographic evaluation and surveillance in patients with cEDS and hEDS in the absence of clinical findings or positive family history.

Identification of known and unknown genes associated with mitral valve prolapse using an exome slice methodology

PURPOSE

Although a familial distribution has been documented, the genetic aetiology of mitral valve prolapse (MVP) is largely unknown, with only four genes identified so far: FLNA, DCHS1, DZIP1 and PLD1. The aim of this study was to evaluate the genetic yield in known causative genes and to identify possible novel genes associated with MVP using a heart gene panel based on exome sequencing.

METHODS

Patients with MVP were referred for genetic counselling when a positive family history for MVP was reported and/or Barlow's disease was diagnosed. In total, 101 probands were included to identify potentially pathogenic variants in a set of 522 genes associated with cardiac development and/or diseases.

RESULTS

97 (96%) probands were classified as Barlow's disease and 4 (4%) as fibroelastic deficiency. Only one patient (1%) had a likely pathogenic variant in the known causative genes (DCHS1). However, an interesting finding was that 10 probands (11%) had a variant that was classified as likely pathogenic in six different, mostly cardiomyopathy genes: DSP (1×), HCN4 (1×), MYH6 (1×), TMEM67 (1×), TRPS1 (1×) and TTN (5×).

CONCLUSION

Exome slice sequencing analysis performed in MVP probands reveals a low genetic yield in known causative genes but may expand the cardiac phenotype of other genes. This study suggests for the first time that also genes related to cardiomyopathy may be associated with MVP. This highlights the importance to screen these patients and their family for the presence of arrhythmias and of 'disproportionate' LV remodelling as compared with the severity of mitral regurgitation, unravelling a possible coexistent cardiomyopathy.

Characteristic Histopathological Findings and Cardiac Arrest Rhythm in Isolated Mitral Valve Prolapse and Sudden Cardiac Death

Background

The association between mitral valve prolapse (MVP) and sudden death remains controversial. We aimed to describe histopathological changes in individuals with autopsy‐determined isolated MVP (iMVP) and sudden death and document cardiac arrest rhythm.

Methods and Results

The Australian National Coronial Information System database was used to identify cases of iMVP between 2000 and 2018. Histopathological changes in iMVP and sudden death were compared with 2 control cohorts matched for age, sex, height, and weight (1 group with noncardiac death and 1 group with cardiac death). Data linkage with ambulance services provided cardiac arrest rhythm for iMVP cases. From 77 221 cardiovascular deaths in the National Coronial Information System database, there were 376 cases with MVP. Individual case review yielded 71 cases of iMVP. Mean age was 49±18 years, and 51% were women. Individuals with iMVP had higher cardiac mass (447 g versus 355 g; P<0.001) compared with noncardiac death, but similar cardiac mass (447 g versus 438 g; P=0.64) compared with cardiac death. Individuals with iMVP had larger mitral valve annulus compared with noncardiac death (121 versus 108 mm; P<0.001) and cardiac death (121 versus 110 mm; P=0.002), and more left ventricular fibrosis (79% versus 38%; P<0.001) compared with noncardiac death controls. In those with iMVP and witnessed cardiac arrest, 94% had ventricular fibrillation.

Conclusions

Individuals with iMVP and sudden death have increased cardiac mass, mitral annulus size, and left ventricular fibrosis compared with a matched cohort, with cardiac arrest caused by ventricular fibrillation. The histopathological changes in iMVP may provide the substrate necessary for development of malignant ventricular arrhythmias.

Mitral annulus morphometry in degenerative mitral regurgitation phenotypes

OBJECTIVES

Degenerative mitral regurgitation (DMR) is classified into different phenotypes based on the extent of leaflet degeneration. Our aim is to demonstrate that phenotype complexity predicts the extent of structural abnormalities of mitral annulus (MA).

METHODS AND RESULTS

Seventy-five patients with DMR and severe valve regurgitation and 23 patients with normal mitral valve were studied using 3D transesophageal echocardiography. Classification of DMR was done by allocating each 3D echocardiography result under five categories: fibroelastic deficiency (FED), FED+, forme fruste, Barlow's disease Mitral annular disjunction (BD MAD)- or BD MAD+. MA was reconstructed in early systole and in end systole. We tested for a trend toward enlargement and flattening of MA in end systole and for a difference in MA dynamics from early systole to end systole with a worsening of DMR phenotype, in the whole spectrum of subjects ranging from controls to BD MAD+. A significant trend was observed toward larger anteroposterior diameter, intercommissural diameter, annulus circumference, and annulus area (P < .001). A reduction was found in annulus height to commissural width ratio (P = .003): This indicates a progressive MA flattening. Prolapse height and prolapse volume tended to be larger (P < .001).

CONCLUSION

Based on the extent of leaflet degeneration, DMR is classified into different phenotypes. As the disease progresses, a related increase in MA size is found, with rounder annular shape, loss of saddle shape, and increase in height and volume of leaflet prolapse. The most pronounced alterations are found in BD MAD+.