Endocardial Fibroelastosis Resection: When it Works and When it Does Not.

Endocardial fibroelastosis (EFE) is a thickening of the endocardial layer by accumulation of collagen and elastic fibers. Endothelial to mesenchymal transformation is proposed to be the underlying mechanism of formation. Although EFE can occur in both right and left ventricles, this article will focus on management of left ventricular EFE. Through its fibrous, nonelastic manifestation EFE restricts the myocardium leading to diastolic and systolic ventricular dysfunction and prevents ventricular growth in neonates and infants. The presence of EFE may be a marker for underlying myocardial fibrosis as well. The extent of EFE within the left ventricular cavity can be variable ranging from patchy to confluent distribution. Similarly the depth of penetration and degree of infiltration into myocardium can be variable. The management of EFE is controversial, although resection of EFE has been reported as part of the staged ventricular recruitment therapy. Following resection, EFE recurs and infiltrates the myocardium after primary resection. Herein we review the current experience with EFE resection.

Endocardial fibroelastosis in infants and young children: a state-of-the-art review.

Endocardial fibroelastosis (EFE) is a rare cardiac condition characterized by excessive endocardial thickening secondary to fibroelastic tissues that commonly present in infants and young children. Most of endocardial fibroelastosis cases are secondary forms, which occur in conjunction with other cardiac diseases. Endocardial fibroelastosis has been associated with poor prognosis and outcomes. In light of recent advancements in understanding pathophysiology, several new data have revealed compelling evidence that abnormal endothelial-to-mesenchymal transition is the root cause of endocardial fibroelastosis. This article aims to review the recent development in pathophysiology, diagnostic workup, and management, and to discuss possible differential diagnoses.

Patterns of endocardial fibroelastosis without atrioventricular block in fetuses exposed to anti-Ro/SSA antibodies.

Anti-Ro/SSA-antibody-mediated endocardial fibroelastosis (EFE) without atrioventricular (AV) block at presentation is a rare cardiac phenotype. We report on 11 fetuses with this rare type of anti-Ro/SSA-antibody-mediated cardiac involvement, presenting with a distinctive echocardiographic pattern of EFE. Eleven fetuses with isolated EFE at presentation were included from four cardiac centers, and experienced fetal cardiologists reached a consensus regarding EFE location on echocardiography at presentation. Interval changes to subsequent fetal and postnatal echocardiograms were assessed to evaluate response to therapy. Echocardiographic markers of cardiac performance, including diastolic function and AV conduction, were reviewed. Ten fetuses were found to have EFE of the aortic root, proximal aorta and/or left ventricular outflow tract. In the same 10 cases, EFE of the pulmonary root, pulmonary artery and/or right ventricular outflow tract was identified. Six cases had atrial EFE and six had EFE of the crux. Four cases were known to be positive for anti-Ro/SSA antibodies prior to diagnosis, whereas, in the remaining seven, echocardiographic findings prompted testing, which was positive in all cases. The AV interval at presentation was normal in all cases, but one fetus subsequently developed AV block. Nine patients were treated with transplacental dexamethasone, five of which also received intravenous immunoglobulin (IVIG), and one received IVIG only. Of the 10 treated cases, six had improvement in EFE as shown by serial imaging and, in four cases, the severity was unchanged. All patients were liveborn. In our cohort, EFE of the aortic and pulmonary arteries and outflow tracts was nearly universal, and involvement of the atria and the crux of the heart was also common. The high survival rate and low burden of AV block are also suggestive of a distinct phenotype of anti-Ro/SSA-antibody-mediated cardiac disease with a favorable prognosis. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Left ventricular non-compaction cardiomyopathy: restrictive subtype with MYH7 gene mutation.

Left ventricular non-compaction is a very rare, still unclassified congenital cardiomyopathy. Nine distinct subtypes of functional and anatomical left ventricular non-compaction have been identified. Studies on the prognosis and mortality of subtypes are ongoing. Our study presented the first restrictive subtype left ventricular non-compaction case with family history and MYH7 gene mutation.

Loss of Nexilin function leads to a recessive lethal fetal cardiomyopathy characterized by cardiomegaly and endocardial fibroelastosis.

The Nexilin F-Actin Binding Protein (Nexilin) encoded by NEXN is a cardiac Z-disc protein important for cardiac function and development in humans, zebrafish, and mice. Heterozygote variants in the human NEXN gene have been reported to cause dilated and hypertrophic cardiomyopathy. Homozygous variants in NEXN cause a lethal form of human fetal cardiomyopathy, only described in two patients before. In a Swedish, four-generation, non-consanguineous family comprising 42 individuals, one female had three consecutive pregnancies with intrauterine fetal deaths caused by a lethal form of dilated cardiomyopathy. Whole-exome sequencing and variant analysis revealed that the affected fetuses were homozygous for a NEXN variant (NM_144573:c.1302del;p.(Ile435Serfs*3)). Moreover, autopsy and histology staining declared that they presented with cardiomegaly and endocardial fibroelastosis. Immunohistochemistry staining for Nexilin in the affected fetuses revealed reduced antibody staining and loss of striation in the heart, supporting loss of Nexilin function. Clinical examination of seven heterozygote carriers confirmed dilated cardiomyopathy (two individuals), other cardiac findings (three individuals), or no cardiac deviations (two individuals), indicating incomplete penetrance or age-dependent expression of dilated cardiomyopathy. RNA sequencing spanning the variant in cDNA blood of heterozygote individuals revealed nonsense-mediated mRNA decay of the mutated transcripts. In the current study, we present the first natural course of the recessively inherited lethal form of human fetal cardiomyopathy caused by loss of Nexilin function. The affected family had uneventful pregnancies until week 23-24, followed by fetal death at week 24-30, characterized by cardiomegaly and endocardial fibroelastosis.

Mechanical strain triggers endothelial-to-mesenchymal transition of the endocardium in the immature heart.

BACKGROUND: Endothelial-to-mesenchymal-transition (EndMT) plays a major role in cardiac fibrosis, including endocardial fibroelastosis but the stimuli are still unknown. We developed an endothelial cell (EC) culture and a whole heart model to test whether mechanical strain triggers TGF-ß-mediated EndMT. METHODS: Isolated ECs were exposed to 10% uniaxial static stretch for 8 h (stretch) and TGF-ß-mediated EndMT was determined using the TGF-ß-inhibitor SB431542 (stretch + TGF-ß-inhibitor), BMP-7 (stretch + BMP-7) or losartan (stretch + losartan), and isolated mature and immature rats were exposed to stretch through a weight on the apex of the left ventricle. Immunohistochemical staining for double-staining with endothelial markers (VE-cadherin, PECAM1) and mesenchymal markers (αSMA) or transcription factors (SLUG/SNAIL) positive nuclei was indicative of EndMT. RESULTS: Stretch-induced EndMT in ECs expressed as double-stained ECs/total ECs (cells: 46 ± 13%; heart: 15.9 ± 2%) compared to controls (cells: 7 ± 2%; heart: 3.1 ± 0.1; p < 0.05), but only immature hearts showed endocardial EndMT. Inhibition of TGF-ß decreased the number of double-stained cells significantly, comparable to controls (cells/heart: control: 7 ± 2%/3.1 ± 0.1%, stretch: 46 ± 13%/15 ± 2%, stretch + BMP-7: 7 ± 2%/2.9 ± 0.1%, stretch + TGF-ß-inhibitor (heart only): 5.2 ± 1.3%, stretch + losartan (heart only): 0.89 ± 0.1%; p < 0.001 versus stretch). CONCLUSIONS: Endocardial EndMT is an age-dependent consequence of increased strain triggered by TGF- ß activation. Local inhibition through either rebalancing TGF-ß/BMP or with losartan was effective to block EndMT. IMPACT: Mechanical strain imposed on the immature LV induces endocardial fibroelastosis (EFE) formation through TGF-ß-mediated activation of endothelial-to-mesenchymal transition (EndMT) in endocardial endothelial cells but has no effect in mature hearts. Local inhibition through either rebalancing the TGF-ß/BMP pathway or with losartan blocks EndMT. Inhibition of endocardial EndMT with clinically applicable treatments may lead to a better outcome for congenital heart defects associated with EFE.

Paediatric dilated cardiomyopathy with and without endocardial fibroelastosis - a pathological analysis of 89 explants.

Heart failure due to dilated cardiomyopathy is a major indication for paediatric cardiac transplantation. Endocardial fibroelastosis is a recognised pathological finding of unknown prognostic significance in paediatric dilated cardiomyopathy. To evaluate the nature of the association between left ventricular endocardial fibroelastosis and paediatric dilated cardiomyopathy, we reviewed surgical pathology reports of dilated cardiomyopathy explants (1986-2016) in order to characterise the pathological findings and to compare and contrast their frequency among four age groups: less than 1 year; 1-5 years; 6-10 years; and greater than 11 years. The 89 explants (47 males and 42 females) were all characterised by increased weight and left ventricular chamber dilatation without increased wall thickness. Ninety-five per cent of the specimens in the two youngest subsets had left ventricular endocardial fibroelastosis. Compared to the oldest age group, recipients aged 1-5 years had a 6-fold increase and those younger than 1 year a 19-fold increase in the odds of observing left ventricular endocardial fibroelastosis. Explants with and without endocardial fibroelastosis were otherwise phenotypically similar. In paediatric dilated cardiomyopathy endocardial fibroelastosis is a very common pathological finding, especially in infants and young children. We propose that the descriptive, clinico-pathological designation "Dilated Cardiomyopathy with Endocardial Fibroelastosis" should be adopted to facilitate future investigation into the potential prognostic/therapeutic significance of left ventricular endocardial fibroelastosis.

A rare cause of sudden unexpected death syndrome (SUDS) in the first year of life: endomyocardial fibroelastosis (EFE) due to two compound heterozygous MYBPC3 mutations.

BACKGROUND: Autopsies regularly aim to clarify the cause of death; however, relatives may directly benefit from autopsy results in the setting of heritable traits ("mortui vivos docent"). CASE PRESENTATION: A case of a sudden unexpected cardiac death of a 5.5-months-old child is presented. Autopsy and thorough postmortem cardiac examinations revealed a massively enlarged heart with endomyocardial fibroelastosis. Postmortem molecular testing (molecular autopsy) revealed an unusual combination of two biparental MYBPC3 gene mutations likely to underlie the cardiac abnormalities. Thus, the molecular autoptic findings also had consequences for the relatives of the deceased child and impact on further family planning. CONCLUSIONS: The presented case highlights the need for clinical autopsies including cardiac examinations and postmortem molecular testing; it also paves the way for further cascade screening of family members for cardiac disease, if a distinct genetic disorder is suspected.

Left Ventricular Recruitment in Patients With Hypoplastic Left Heart Syndrome.

Hypoplastic left heart complex with "borderline left ventricle" and intact ventricular septum is a clinical conundrum for the congenital heart surgeon. The choice between neonatal biventricular repair and single ventricle palliation can be challenging, and the current tools to aid in the decision-making process fail to account for the morbidity associated with intermediate and late diastolic dysfunction. Staged ventricular recruitment, consisting of valvular repair techniques, resection of endocardial fibroelastosis, atrial septal restriction, and augmentation of pulmonary blood flow, has been shown to improve left ventricular size and function culminating in eventual biventricular circulation. Despite staged ventricular recruitment, some patients cannot undergo biventricular conversion. Strategies to address these complex patients, including the "reverse" double switch, are the next frontier in biventricular repair.

[HYPOPLASTIC LEFT HEART SYNDROME: MORPHOGENESIS OF PATOMORPHOLOGICAL TYPES OF THE LEFT VENTRICLE].

The purpose of the study was to investigate the morphogenesis of the left ventricle in the hypoplastic left heart syndrome (HLHS). There are five types of hypoplastic left ventricles were identified: with a slit-like shape and hypoplasia of LV wall, with a slit-like cavity shape and wall hypertrophy and types with endocardial fibroelastosis (with a cylindrical cavity shape, with lacunar cavities and lacunar-cylindrical cavity of the left ventricle), as a result of differences in the wall structure, cavity shape, presence or absence of endocardial fibroelastosis. The analysis of morphometric data of pathomorphological types of the left ventricle in the HLHS revealed the possible ways of their morphogenesis. Left displacement of interventricular septum in embryogenesis at 4-5 weeks of intrauterine development is associated with the occurrence of atresia of the left atrioventricular orifice and aortic valve and the appearance of a slit-like shape and hypoplasia of LV wall in the HLHS. The displacement of only the conotruncus septum leads to the appearance of a slit-like shape of cavity and hypertrophy of LV wall in the HLHS. The pathomorphological types with endocardial fibroelastosis in the HLHS depends on the stage of embryogenesis of myocardium at which fibroelastosis appears: before the myocardial compaction (up to 4th week of gestation) - the lacunar shape of LV cavity with thin compact layer of myocardium; during the compaction of myocardium (5-6th week of gestation) - the lacunar-cylindrical shape of LV cavity and after compaction (after 7-8th week of fetal development) - a cylindrical shape of LV cavity.

Endocardial Fibroelastosis is Secondary to Hemodynamic Alterations in the Chick Embryonic Model of Hypoplastic Left Heart Syndrome.

BACKGROUND: Endocardial fibroelastosis (EFE) is a diffuse thickening of the ventricular endocardium, causing myocardial dysfunction and presenting as unexplained heart failure in infants and children. One of the postulated causes is persistent and increased wall tension in the ventricles. RESULTS: To examine whether reduced ventricular pressure in a chick model of hypoplastic left heart syndrome (HLHS) induced by left atrial ligation (LAL) at embryonic day (ED) 4 is associated with EFE at later stages, myocardial fibrosis was evaluated by histology and immunoconfocal microscopy and mass spectrometry (MS) at ED12. Immunohistochemistry with collagen I antibody clearly showed a significant thickening of the layer of subendocardial fibrous tissue in LAL hearts, and MS proved this significant increase of collagen I. To provide further insight into pathogenesis of this increased fibroproduction, hypoxyprobe staining revealed an increased extent of hypoxic regions, normally limited to the interventricular septum, in the ventricular myocardium of LAL hearts at ED8. CONCLUSIONS: Abnormal hemodynamic loading during heart development leads to myocardial hypoxia, stimulating collagen production in the subendocardium. Therefore, EFE in this chick embryonic model of HLHS appears to be a secondary effect of abnormal hemodynamics. Developmental Dynamics 247:509-520, 2018. © 2017 Wiley Periodicals, Inc.

Sudden cardiac death in isolated right ventricular hypertrabeculation/noncompaction cardiomyopathy.

Hypertrabeculation/noncompaction of the myocardium is a rare disorder that involves most commonly the left ventricle of the heart and it has been recognized as a distinct cardiomyopathy by the World Health Organization. However, it is extremely rare for this condition to involve exclusively the right ventricle. We report the cases of three patients who presented with ventricular tachyarrhythmia and sudden cardiac death. They were found to have isolated right ventricular hypertrabeculation/noncompaction on echocardiography. This supports the hypothesis that this condition is highly arrhythmogenic and is associated with high mortality similarly to the left ventricular hypertrabeculation/noncompaction cardiomyopathy.

Endocardial Fibroelastosis of the Left Ventricle Affects Right Ventricular Performance in Fetuses with Hypoplastic Left Heart Syndrome: A Prospective Study Using M-Mode, PW- and Tissue Doppler Techniques.

PURPOSE: Myocardial function (MF) of the systemic right ventricle (RV) influences the postnatal course of neonates with hypoplastic left heart syndrome (HLHS). Our study examines whether the presence of endocardial fibroelastosis of the left ventricle (LV EFE) influences MF of the RV in HLHS fetuses. MATERIALS AND METHODS: A prospective study was conducted including 10 controls (group 1), 10 HLHS fetuses with (group 2) and 10 without LV EFE (group 3) - all matched for gestational age. M-mode was used to assess tricuspid plane systolic excursion (TAPSE) and the shortening fraction (SF). PW-Doppler-derived and PW-TDI-derived velocities were assessed. E/A, E/e', e'/a' ratios and the myocardial performance index (mpi') were calculated. RESULTS: The examination of MF revealed significantly lower s' velocities (p < 0.05) and higher values for SF in group 2 compared to group 3. e'/a' ratio, et' (ejection time), E wave velocity, E/e' and SF showed significantly higher values in group 2 compared to group 1. In group 2 a' velocity increased significantly over gestational age. In group 3 but not in group 2, TAPSE increased during gestation. CONCLUSION: These significant differences in MF between the groups might lend support to the notion of negative ventricular-ventricular interaction in the case of HLHS with LV EFE possibly influencing surgical outcomes.

Endocardial fibroelastosis is caused by aberrant endothelial to mesenchymal transition.

RATIONALE: Endocardial fibroelastosis (EFE) is a unique form of fibrosis, which forms a de novo subendocardial tissue layer encapsulating the myocardium and stunting its growth, and which is typically associated with congenital heart diseases of heterogeneous origin, such as hypoplastic left heart syndrome. Relevance of EFE was only recently highlighted through the establishment of staged biventricular repair surgery in infant patients with hypoplastic left heart syndrome, where surgical removal of EFE tissue has resulted in improvement in the restrictive physiology leading to the growth of the left ventricle in parallel with somatic growth. However, pathomechanisms underlying EFE formation are still scarce, and specific therapeutic targets are not yet known. OBJECTIVE: Here, we aimed to investigate the cellular origins of EFE tissue and to gain insights into the underlying molecular mechanisms to ultimately develop novel therapeutic strategies. METHODS AND RESULTS: By utilizing a novel EFE model of heterotopic transplantation of hearts from newborn reporter mice and by analyzing human EFE tissue, we demonstrate for the first time that fibrogenic cells within EFE tissue originate from endocardial endothelial cells via aberrant endothelial to mesenchymal transition. We further demonstrate that such aberrant endothelial to mesenchymal transition involving endocardial endothelial cells is caused by dysregulated transforming growth factor beta/bone morphogenetic proteins signaling and that this imbalance is at least in part caused by aberrant promoter methylation and subsequent transcriptional suppression of bone morphogenetic proteins 5 and 7. Finally, we provide evidence that supplementation of exogenous recombinant bone morphogenetic proteins 7 effectively ameliorates endothelial to mesenchymal transition and experimental EFE in rats. CONCLUSIONS: In summary, our data point to aberrant endothelial to mesenchymal transition as a common denominator of infant EFE development in heterogeneous, congenital heart diseases, and to bone morphogenetic proteins 7 as an effective treatment for EFE and its restriction of heart growth.

Prolapse Volume to Prolapse Height Ratio for Differentiating Barlow's Disease From Fibroelastic Deficiency.

BACKGROUND: As mitral valve (MV) repair for Barlow's disease remains surgically challenging, it is important to distinguish Barlow's disease from fibroelastic deficiency (FED) preoperatively. We hypothesized that the prolapse volume to prolapse height ratio (PV-PH ratio) may be useful to differentiate Barlow's disease and FED.Methods and Results:In 76 patients with MV prolapse who underwent presurgical transesophageal echocardiography, the 3D MV morphology was quantified: 19 patients were diagnosed with Barlow's disease and 57 with FED. The patients with Barlow's disease had greater prolapse volume and height than the patients with FED, as well as greater PV-PH ratio (0.61±0.35 vs. 0.17±0.10, P<0.001). Receiver-operating characteristic analysis revealed that with a cutoff value of 0.27, the PV-PH ratio differentiated Barlow's disease from FED with 84.2% sensitivity and 84.2% specificity. Net reclassification improvement showed that the differentiating ability of the PV-PH ratio was significantly superior to prolapse volume (1.30, P<0.001). After being adjusted by each of prolapse volume and height, annular area and shape, and the number of prolapsed segments, the PV-PH ratio had an independent association with Barlow's disease. CONCLUSIONS: The PV-PH ratio was able to differentiate Barlow's disease from FED with high accuracy. 3D quantification including this value should be performed before MV repair.

Serial echocardiography for immune-mediated heart disease in the fetus: results of a risk-based prospective surveillance strategy.

OBJECTIVE: Mothers carrying anti-Ro antibodies are frequently referred for weekly echocardiograms to early detect and treat antibody-mediated fetal heart disease. We tested a surveillance strategy based on anti-Ro antibody titers. METHODS: From 2009 to 2014, 232 pregnancies were referred for maternal anti-Ro antibodies. At the baseline echocardiogram, anti-Ro titers were measured by enzyme-linked immunosorbent essay and results categorized as negative (<8 U/mL; n = 43; excluded), low-moderate positive (8-49 U/mL; n = 62; group 1) or high positive (50 - >100 U/mL; n = 127; group 2). Serial echocardiograms to ≥24 weeks were only recommended for group 2 mothers. RESULTS: Group 1 patients underwent significantly less fetal echocardiograms when compared with group 2 mothers (median 2 vs. 4; p < 0.001). Isolated endocardial fibroelastosis (n = 1) and incomplete (n = 4) or complete (n = 4) heart block were diagnosed in 9 (8%) pregnancies with anti-Ro titers >100 U/mL but none with lower titers (odds ratio 17.78; p = 0.004). Incomplete block and endocardial fibroelastosis regressed with transplacental corticosteroid and immune globulin therapy. CONCLUSIONS: Limiting serial fetal echocardiograms to women with high anti-Ro antibody levels is safe and more cost effective. While numbers of echocardiograms were significantly reduced in referrals with anti-Ro titers <50 U/mL, reversible abnormalities with prenatal treatment were detected by serial echocardiography in group 2 patients. © 2017 John Wiley & Sons, Ltd.

Surgical Treatment of Cardiac Tumors: Insights from an 18-Year Single-Center Analysis.

BACKGROUND The aim of this study was to investigate the clinical presentation, operative data, and early and late outcomes of a large patient cohort undergoing surgical treatment for cardiac tumors in our institution. MATERIAL AND METHODS A total of 181 patients underwent surgery because of suspected cardiac tumor in our institution between 1998 and 2016. In 162 cases, the diagnosis was confirmed postoperatively and these patients were included in this study. Preoperative baseline characteristics, operative data, and postoperative early and long-term outcomes were analyzed. RESULTS Mean age at presentation was 56.6±17.6 years, and 95 (58.6%) patients were female. There were 126 (77.8%) patients with benign cardiac tumors, while the remaining patients had malignant tumors (primary and metastasized). The mean follow-up time was 5.2±4.7 years. The most frequent histologically verified tumor type was myxoma (63%, n=102). In terms of malignant tumors, various types of sarcomas presented most primary malignant cardiac tumors (7.4%, n=12). The mean ICU length of stay was 1.7±2.2 days and overall in-hospital mortality was 3.1% (n=5). Frequent postoperative complications included mediastinal bleeding (5.8%, n=9), wound infection (1.3%, n=2), acute renal failure (5.6%, n=9), and major cerebrovascular events (n=7, 4.6%). The overall cumulative survival after cardiac tumor resection was 94% at 30 days, 85% at 1 year, 72% at 5 years, and 59% at 15 years. CONCLUSIONS Surgical treatment of cardiac tumors is a safe and highly effective strategy associated with good early and long-term outcomes.

[Changes in serum chromogranin A and urotensin II levels in children with chronic heart failure].

OBJECTIVE: To examine the changes in serum chromogranin A (CgA) and urotensin II (U II) levels in children with chronic heart failure (CHF) and their clinical significance. METHODS: A total of 58 children with CHF, among whom 17 had endocardial fibroelastosis (EFE) and 41 had dilated cardiomyopathy (DCM), were selected as CHF group, and 20 healthy children were selected as control group. Serum levels of CgA and U II were measured using enzyme-linked immunosorbent assay, and the level of N-terminal pro-brain natriuretic peptide (NT-proBNP) was determined by bi-directional lateral flow immunoassay. Ventricular remodeling indices were measured using echocardiography. The correlation between serum CgA and U II levels and ventricular remodeling was evaluated by Pearson correlation or Spearman's rank correlation analysis. RESULTS: There were no significant differences in serum CgA and NT-proBNP levels between children with grade II heart function and the control group (P>0.05). However, the serum CgA and NT-proBNP levels gradually increased as the heart function grade increased, and were significantly higher in grade III and IV children compared to those in the control group (P<0.05). U II levels were lower in children with grade II, III, or IV heart function than those in the control group (P<0.05), and significantly decreased with the aggravation of CHF (P<0.05). There were no significant differences in CgA and U II levels between patients with EFE and DCM (P>0.05). Serum CgA concentration was positively correlated with left ventricular mass index (LVMI), NT-proBNP, and cardiac function classification (r=0.279, 0.649, and 0.778 respectively; P<0.05), but was negatively correlated with left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), and U II (r=-0.369, -0.322, and -0.718 respectively; P<0.05). Serum U II concentration was negatively correlated with NT-proBNP and cardiac function classification (r=-0.472 and -0.591 respectively; P<0.05), but was not correlated with LVMI, LVEF, and LVFS (P>0.05). CONCLUSIONS: CgA may play a role in ventricular remodeling in children with CHF. Serum CgA and U II may serve as a reference for the diagnosis and functional classification of heart failure.

Knock-out of nexilin in mice leads to dilated cardiomyopathy and endomyocardial fibroelastosis.

Cardiomyopathy is one of the most common causes of chronic heart failure worldwide. Mutations in the gene encoding nexilin (NEXN) occur in patients with both hypertrophic and dilated cardiomyopathy (DCM); however, little is known about the pathophysiological mechanisms and relevance of NEXN to these disorders. Here, we evaluated the functional role of NEXN using a constitutive Nexn knock-out (KO) mouse model. Heterozygous (Het) mice were inter-crossed to produce wild-type (WT), Het, and homozygous KO mice. At birth, 32, 46, and 22 % of the mice were WT, Het, and KO, respectively, which is close to the expected Mendelian ratio. After postnatal day 6, the survival of the Nexn KO mice decreased dramatically and all of the animals died by day 8. Phenotypic characterizations of the WT and KO mice were performed at postnatal days 1, 2, 4, and 6. At birth, the relative heart weights of the WT and KO mice were similar; however, at day 4, the relative heart weight of the KO group was 2.3-fold higher than of the WT group. In addition, the KO mice developed rapidly progressive cardiomyopathy with left ventricular dilation and wall thinning and decreased cardiac function. At day 6, the KO mice developed a fulminant DCM phenotype characterized by dilated ventricular chambers and systolic dysfunction. At this stage, collagen deposits and some elastin deposits were observed within the left ventricle cavity, which resembles the features of endomyocardial fibroelastosis (EFE). Overall, these results further emphasize the role of NEXN in DCM and suggest a novel role in EFE.

The myocardial and coronary histopathology and pathogenesis of hypoplastic left heart syndrome.

Hypoplastic left heart syndrome has the greatest mortality rate among all CHDs and without palliation is uniformly fatal. Despite noble efforts, the aetiology of this syndrome is unknown and a cure remains elusive. The genetic and anatomic heterogeneity of hypoplastic left heart syndrome supports a rethinking of old hypotheses and warrants further investigation into the histological and vascular variations recognised with this syndrome. In an effort to elucidate the pathogenesis of hypoplastic left heart syndrome, this review will focus on its unique myocardial and coronary pathology as well as evaluate the association of hypoplastic left heart syndrome with the endocardial fibroelastosis reaction.