Prenatal ultrasound diagnosis of fetal isolated right ventricular noncompaction with pulmonary artery sling: A rare case report.

Noncompaction of the ventricular myocardium (NVM), also known as spongy myocardium, is a rare type of cardiomyopathy that has a serious impact on fetuses, children, and adults. NVM mainly affects the left ventricle, as isolated right ventricular noncompaction (IRVNC) is rare. Pulmonary artery sling (PAS) is a rare condition in which the left pulmonary artery anomalously originates from a normal positioned right pulmonary artery, and only a few studies have reported PAS in fetuses. Fetal IRVNC complicated with PAS has not been reported yet. Here, we report a case of IRVNC complicated with PAS that was diagnosed prenatally at 30 weeks gestation and confirmed by postpartum anatomy and pathology.

Excessive trabeculations in noncompaction do not have the embryonic identity.

BACKGROUND: Ventricular noncompaction is characterized by excessive trabeculations and is associated with heart failure. The lesion is hypothesized to result from failed compaction and thus retention of embryonic trabeculations. Here, we assess for the first time the identity of trabeculations in noncompaction to test whether noncompacted hearts show retention of embryonic trabeculations. METHODS: Using immunohistochemistry, we analyzed cardiac sections of the heart of a control embryo, 3 cases of fetal noncompaction (a set of twins and an unrelated fetus) and 3 fetal hearts without noncompaction. RESULTS: In the embryo, the ventricular trabeculations strongly expressed ANF/NPPA whereas the compact wall did not. In the noncompaction hearts, trabeculations constituted an excessively thick layer. In noncompaction and control fetal hearts alike, however, only a miniscule subset of sub-endocardial myocardium of the trabeculations most proximal to the central ventricular lumen exhibited strong expression of ANF/NPPA, representing Purkinje myocardium. The trabeculations of both fetal control and noncompaction hearts were ANF-negative and orders of magnitude wider than those of the embryo. Both the compact and noncompaction trabeculated myocardium were rich in coronary vasculature. Like embryonic trabeculations, the ANF+ Purkinje myocardium had little if any vasculature. CONCLUSION: The excessive trabeculations in noncompaction do not have the embryonic identity and noncompaction is probably not the result of failed compaction. We propose the lesion results from the compact wall growing into the ventricular lumen in a trabecular fashion.

A novel MYH7 gene mutation in a fetus with left ventricular noncompaction.

Left ventricular noncompaction (LVNC) is a recently defined cardiomyopathy characterized by a pattern of prominent trabecular meshwork and deep intertrabecular recesses. LVNC is rarely described in fetal life, and a small number of cases have been reported. We report the first fetal case, to our knowledge, of LVNC associated with a novel mutation in the MYH7 gene (c.1625A>C; p.Lys542Thr). This patient showed cardiomegaly on prenatal ultrasonographic examinations, with features indicating noncompaction of the myocardium apparent in the second trimester. This case highlights the importance of prenatal ultrasonography for the diagnosis of LVNC and suggests that abnormal myocardial development underlies the pathogenesis of LVNC.

Noncompaction in the fetus and neonate: an autopsy study.

Noncompaction refers to an uncommon structural abnormality of the heart's ventricular myocardium characterized by an abnormally thick layer of left ventricular trabeculations, as well as hypoplastic papillary muscles. The condition is associated with a variable clinical phenotype including heart failure, thromboembolism, and sudden death. In this retrospective study of fetal and neonatal autopsy hearts with noncompaction, clinical profiles were correlated with gross and histologic findings and compared with a set of age-matched controls. Pathologic criteria for noncompaction included hypoplastic left ventricular papillary muscles, abnormal trabecular architecture and greater than 50% penetration of the left ventricular wall thickness by intertrabecular recesses. Among eight fetuses and full-term neonates with pathologic features of noncompaction, all had evidence of severe heart failure, including four with complete heart block and two others with bradycardia. None experienced sudden death. Seven of eight hearts had associated heart malformations-four with left atrial isomerism, two with aortic and/or pulmonary valve dysplasia consistent with stenosis and, one with atrial septal defect. One heart with noncompaction had no associated malformations. With characteristic excessive trabeculation in the left ventricle, noncompaction also included biventricular endocardial fibroelastosis that denoted right ventricular involvement in all hearts. Thus, (1) among autopsied fetuses and neonates with noncompaction, heart failure including heart block is a common cause of death, (2) noncompaction is often associated with various cardiovascular malformations, but even in isolation it can be the basis for severe cardiac failure, and (3) biventricular endocardial fibroelastosis in noncompaction suggests a global pathologic process.

Isolated left ventricular noncompaction: what do we really know?

Isolated left ventricular noncompaction (ILVNC) is a myocardial disorder thought to occur as a result of an arrest in embryogenesis. Recently, it has been classified as a genetic cardiomyopathy. Familial and sporadic forms of ILVNC have been documented. There is considerable genetic heterogeneity among familial forms, although sarcomeric mutations are the most common genetic mutations. Issues related to familial screening require careful consideration and future research. There is considerable controversy regarding several aspects relating to pathogenesis, diagnosis, and management of subjects with ILVNC. Differentiating some cases of ILVNC from normal variant myocardial architecture is challenging and requires future work. This review is intended to provide clinicians insight into several aspects of these challenging issues and offer some practical guidance in dealing with some of these difficult clinical scenarios.

Prenatal diagnosis of fetal left ventricular non-compaction cardiomyopathy.

Isolated left ventricular non-compaction (LVNC) is a rare disorder, classified as a primary genetic cardiomyopathy by the American Heart Association or as an unclassified cardiomyopathy by the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases. The key features are the prominent trabeculae and deep intratrabecular recesses resulting in thickened myocardium with the two layers consisting of compacted and non-compacted myocardium. These recesses are in continuity with the left ventricular cavity and are filled with blood without evidence of communication to the epicardial coronary artery system. We present a case of LVNC detected prenatally at 25 + 4 weeks of gestation.

Left ventricular non-compaction revisited: a distinct phenotype with genetic heterogeneity?

Non-compaction of the left ventricular myocardium (LVNC) has gained increasing recognition during the last 25 years. There is a morphological trait of the myocardial structure with a spectrum from normal variants to the pathological phenotype of LVNC, which reflects the embryogenic structure of the human heart due to an arrest in the compaction process during the first trimester. It must be cautioned not to overdiagnose LVNC: the morphological spectrum of trabeculations, from normal variants to pathological trabeculations with the morphological feature of LVNC must be carefully considered. The classical triad of complications are heart failure, arrhythmias, including sudden cardiac death, and systemic embolic events. Non-compaction of the left ventricular myocardium can occur in isolation or in association with congenital heart defects (CHDs), genetic syndromes, and neuromuscular disorders among others. The clinical spectrum is wide and the outcome is more favourable than in previously described populations with a negative selection bias. Familial occurrence is frequent with autosomal dominant and X-linked transmissions. Different mutations in sarcomere protein genes were identified and there seems to be a shared molecular aetiology of different cardiomyopathic phenotypes, including LVNC, hypertrophic and dilated cardiomyopathies. Thus, genetic heterogeneity, with an overlap of different phenotypes, and the variability of hereditary patterns, raise the questions whether there is a morphological trait from dilated/hypertrophic cardiomyopathy to LVNC and what are the triggers and modifiers to develop either dilated, hypertrophic cardiomyopathy, or LVNC in patients with the same mutation. The variety in clinical presentation, the genetic heterogeneity, and the phenotype of the first transgenetic animal model of an LVNC-associated mutation question the hypothesis that LVNC be a distinct cardiomyopathy: it seems to be rather a distinct phenotype or phenotypic, morphological expression of different underlying diseases than a distinct cardiomyopathy.

Left ventricular non compaction in children.

Left ventricular non compaction (LVNC) is a myocardial disease characterized by a hypertrabeculated myocardium. The hypertrabeculations in the left ventricular wall define deep recesses communicating with the left ventricular chamber where blood penetrates with increased risk of blood clots in the meshwork of the prominent trabeculations. The left ventricular apex and the free wall are particularly affected. During in utero ventriculogenesis, myocardial blood supply is initially linked to the presence of sinusoids, in which blood penetrates and diffuses nutriments and oxygen to myocardial cells. Progressively, with the development of the heart and the increase of cells demand of blood, coronary arteries system develops. This step is associated with myocardial modification that leads to compaction of hypertrabeculated myocardial net. Probably, the premature interruption of this process leads to ventricular noncompaction. Many studies have been conducted in adults with hypertrabeculated myocardium. To date, data regarding childhood LVNC are sparse. The aim of this review is to summarize the clinical and preclinical knowledge about LVNC in children.