Clinical features of isolated noncompaction of the ventricular myocardium: long-term clinical course, hemodynamic properties, and genetic background

RCAN family member 3 deficiency contributes to noncompaction of the ventricular myocardium

Noncompaction of the ventricular myocardium (NVM), the third most diagnosed cardiomyopathy, is characterized by prominent trabeculae and intratrabecular recesses. However, the genetic etiology of 40%-60% of NVM cases remains unknown. Here, we identify two infants with NVM, in a nonconsanguineous family, with a typical clinical presentation of persistent bradycardia since the prenatal period. A homozygous missense variant (R223L) of RCAN family member 3 (RCAN3) is detected in both infants using whole-exome sequencing. In the zebrafish model, marked cardiac dysfunction is detected in rcan3 deficiency (MO-rcan3ATG-injected) and rcan-/- embryos. Developmental dysplasia of both endocardial and myocardial layers is also detected in rcan3-deficient embryos. RCAN3 R223L variant mRNAs can not rescue heart defects caused by rcan3 knockdown or knockout; however, hRCAN3 mRNAs rescue these phenotypes. RNA-seq experiments show that several genes involved in cardiomyopathies are significantly regulated through multiple signaling pathways in the rcan3-knockdown zebrafish model. In human cardiomyocytes, RCAN3 deficiency results in reduced proliferation and increased apoptosis, together with an abnormal mitochondrial ultrastructure. Thus, we suggest that RCAN3 is a susceptibility gene for cardiomyopathies, especially NVM and that the R223L mutation is a potential loss-of-function variant.

Case report: A rare case of left ventricular noncompaction in two Chinese siblings with becker muscular dystrophy caused by deletion of exons 10 to 12 in the DMD gene

Background

Becker muscular dystrophy (BMD) is an inherited X-linked recessive condition resulting from mutations of the DMD gene encoding dystrophin. Left ventricular noncompaction (LVNC) is a rare cardiomyopathy morphologically characterized by abnormal myocardial trabeculae and deep recesses in the left ventricle. LVNC in BMD patients has only rarely been reported.

Case report

In the present study, we identified a deletion mutation in exons 10 to 12 (EX10_12 del) of the DMD gene (reference sequence NM_004006.2) in two Chinese siblings with BMD and LVNC by high throughput targeted next-generation sequencing (NGS) and quantitative polymerase chain reaction (qPCR). The proband was a 22-year-old man admitted with dyspnea, abdominal distention, and polyserositis. It is noteworthy that both the proband and his younger brother manifested progressive muscular atrophy and creatine kinase (CK) elevation. Light and electron microscopy examination of muscle biopsies showed the typical features of dystrophinopathies. Cardiac magnetic resonance imaging and echocardiography demonstrated that both brothers had an enlarged left ventricle, LVNC, and reduced left ventricular ejection fraction. Finally, the proband underwent heart transplantation at age 26 with an event-free follow-up over 4 years post-transplantation.

Conclusion

This case further enriches our knowledge of the symptoms, genotype, cardiac performance, management, and prognosis of BMD patients complicated by LVNC. It is recommended that early comprehensive cardiac evaluation should be considered for patients with BMD to exclude LVNC, as this may have a significant impact on their prognosis.

Left ventricular noncompaction in Ibadan, Nigeria

BACKGROUND

There has been an increase in the reporting of cases of left ventricular noncompaction (LVNC) cardiomyopathy in medical literature due to advances in medical imaging. Patients with LVNC may be asymptomatic or may present with arrhythmias, heart failure, thromboembolism or sudden death. LVNC is typically diagnosed by echocardiography, although there are higher-resolution cardiac imaging techniques such as cardiac magnetic resonance imaging (MRI) to make the diagnosis. The objective of the study is to report on a series of 9 cases of LVNC cardiomyopathy seen at the University College Hospital, Ibadan. Cases of LVNC seen between September 1, 2015 and July 31, 2022 in our echocardiography service  is being reported.

RESULTS

There were a total of 6 men and 3 women. Mean age at presentation was 52.89 ± 15.02 years. The most common mode of presentation was heart failure (6 patients). Hypertension was the most common comorbidity (6 patients). Three patients had an ejection fraction of less than 40% and the mean ratio of noncompacted to compacted segment at end-systole was 2.80 ± 0.48. The most common areas of trabecular localization were the LV lateral wall and the apex. Beta blockers were highly useful in the management of the patients.

CONCLUSIONS

LVNC cardiomyopathy is not uncommon in our environment and a high index of suspicion is often required.

Long-Term Outcome of ICD Therapy in Patients With Noncompaction Cardiomyopathy Compared With DCM and HCM

BACKGROUND

Implantable cardioverter-defibrillators (ICDs) are frequently used for primary and secondary prevention in patients with cardiomyopathies due to different etiologies. However, long-term outcome studies in patients with noncompaction cardiomyopathy (NCCM) are scarce.

OBJECTIVES

This study summarizes the long-term outcome of ICD therapy in patients with NCCM compared with those with dilated cardiomyopathy (DCM) or hypertrophic cardiomyopathy (HCM).

METHODS

Prospective data from our single-center ICD registry were used to analyze the ICD interventions and survival in patients with NCCM (n = 68) compared with patients with DCM (n = 458) and patients with HCM (n = 158) from January 2005 to January 2018.

RESULTS

This NCCM population with an ICD for primary prevention comprised 56 (82%) patients with a median age of 43 years and 52% males, compared with 85% in patients with DCM and 79% in patients with HCM (P = 0.20). During a median follow-up of 5 years (IQR: 2.0-6.9 years), appropriate and inappropriate ICD interventions were not significantly different. Nonsustained ventricular tachycardia during Holter monitoring in patients with NCCM was the only significant risk factor for appropriate ICD therapy in patients with NCCM, with a HR of 5.29 (95% CI: 1.12-24.96). The long-term survival was significantly better in the univariable analysis in the NCCM group. However, there was no difference in multivariable Cox regression analyses between the cardiomyopathy groups.

CONCLUSIONS

At 5 years of follow-up, the rate of appropriate and inappropriate ICD interventions in NCCM was comparable to that in DCM or HCM. In multivariable analysis, no differences in survival were found between the cardiomyopathy groups.

Advances in symptomatic therapy for left ventricular non-compaction in children

Left ventricular non-compaction is a complex cardiomyopathy and the third largest childhood cardiomyopathy, for which limited knowledge is available. Both pathogenesis and prognosis are still under investigation. Currently, no effective treatment strategy exists to reduce its incidence or severity, and symptomatic treatment is the only clinical treatment strategy. Treatment strategies are constantly explored in clinical practice, and some progress has been made in coping with the corresponding symptoms because the prognosis of children with left ventricular non-compaction is usually poor if there are complications. In this review, we summarized and discussed the coping methods for different left ventricular non-compaction symptoms.

Coronary Artery Anomalies: A Short Case Series and Current Review

Coronary artery anomalies (CAAs) are rare congenital cardiovascular defects that can present in various ways depending on the origin, course, and termination of the abnormal coronary artery fistula. It is sometimes detected incidentally during procedures such as coronary angiography or autopsies. While adults with this condition are often asymptomatic, some may experience angina, congestive heart failure, myocardial infarction, cardiomyopathy, ventricular aneurysms, or sudden cardiac death (SCD). In fact, it is the second leading cause of SCD among young athletes and requires more studies to handle such patients efficiently. To illustrate the many possible manifestations of this unusual diagnosis, we present a series of five cases. We have also reviewed the different varieties of this rare congenital anomaly and discussed the latest diagnostic tests and treatment plans.

Case report: Myocardial noncompaction causing massive cerebral infarction in 1 patient with eyelid edema as an early manifestation and literature review

Objective

To summarize and analyze the early clinical manifestations, risk factors, treatment and prognosis of myocardial noncompaction in children, and to provide scientific basis for early and effective intervention.

Methods

Combined with a case of myocardial noncompaction with massive cerebral infarction in a child, the related research reports of myocardial noncompaction in children were analyzed retrospectively.

Results

Myocardial noncompaction in children is cardiomyopathy caused by abnormal myocardial compaction during embryonic development. Feeding intolerance, dyspnea, chest tightness, fatigue, eyelid edema and other non-specific manifestations may occur in the early stage. It is easy to miss the diagnosis and misdiagnosis in clinical diagnosis and treatment, leading to intractable heart failure, nausea and arrhythmia, thromboembolism and even sudden death and other serious complications. Early diagnosis, symptomatic treatment, control of complications and regular follow-up can prevent the occurrence of serious complications and reduce mortality.

Conclusion

There is no specific clinical manifestation in the early stage of myocardial noncompaction in children. If it is not detected early and treated symptomatically, the prognosis is poor and the mortality is high. Therefore, clinicians should fully improve the understanding of the early clinical manifestations of this disease, give early diagnosis and early intervention to children, reduce the occurrence of serious complications and improve the survival rate.

Left ventricular non-compaction in paediatrics: a novel semi-automated imaging technique bridging imaging findings and clinical outcomes

Aims

We set out to design a reliable, semi-automated, and quantitative imaging tool using cardiac magnetic resonance (CMR) imaging that captures LV trabeculations in relation to the morphologic endocardial and epicardial surface, or perimeter-derived ratios, and assess its diagnostic and prognostic utility.

Methods and results

We queried our institutional database between January 2008 and December 2018. Non-compacted (NC)-to-compacted (C) (NC/C) myocardium ratios were calculated and our tool was used to calculate fractal dimension (FD), total mass ratio (TMR), and composite surface ratios (SRcomp). NC/C, FD, TMR, and SRcomp were assessed in relation to LVNC diagnosis and outcomes. Univariate hazard ratios with cut-offs were performed using clinically significant variables to find ‘at-risk’ patients and imaging parameters were compared in ‘at-risk’ patients missed by Petersen Index (PI). Ninety-six patients were included. The average time to complete the semi-automated measurements was 3.90 min (SEM: 0.06). TMR, SRcomp, and NC/C were negatively correlated with LV ejection fraction (LVEF) and positively correlated with indexed LV end-systolic volumes (iLVESVs), with TMR showing the strongest correlation with LVEF (−0.287; P = 0.005) and SRcomp with iLVESV (0.260; P = 0.011). We found 29 ‘at-risk’ patients who were classified as non-LVNC by PI and hence, were missed. When compared with non-LVNC and ‘low-risk’ patients, only SRcomp differentiated between both groups (1.91 SEM 0.03 vs. 1.80 SEM 0.03; P = 0.019).

Conclusion

This method of semi-automatic calculation of SRcomp captured changes in at-risk patients missed by standard methods, was strongly correlated with LVEF and LV systolic volumes and may better capture outcome events.

The Electrocardiogram in the Diagnosis and Management of Patients With Left Ventricular Non-Compaction

PURPOSE OF THE REVIEW

Left ventricular non-compaction (LVNC) is characterised by prominent left ventricular trabeculae and deep inter-trabecular recesses. Although considered a distinct cardiomyopathy, prominent trabeculations may also be found in other cardiomyopathies, in athletes or during pregnancy. Clinical presentation includes heart failure symptoms, systemic embolic events, arrhythmias and sudden cardiac death. Currently, LVNC diagnosis relies on imaging criteria, and clinicians face several challenges in the assessment of patients with prominent trabeculations. In this review, we summarise the available information on the role of the ECG in the diagnosis and management of LVNC.

RECENT FINDINGS

ECG abnormalities have been reported in 75-94% of adults and children with LVNC. The lack of specificity of these ECG abnormalities does not allow (in isolation) to diagnose the condition. However, when considered in a set of diagnostic criteria including family history, clinical information, and imaging features, the ECG may differentiate between physiological and pathological findings or may provide clues raising the possibility of specific underlying conditions. Finally, some ECG features in LVNC constitute ominous signs that require a stricter patient surveillance or specific therapeutic measures. The ECG remains a cornerstone in the diagnosis and management of patients with cardiomyopathies, including LVNC.

Left ventricular noncompaction: a disorder with genotypic and phenotypic heterogeneity-a narrative review

Background and Objective

Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized by excessive trabecular formation and deep recesses in the ventricular wall, with a bilaminar structure consisting of an endocardial noncompaction layer and an epicardial compacted layer. Although genetic variants have been reported in patients with LVNC, understanding of LVNC and its pathogenesis has not yet been fully elucidated. We addressed the latest findings on genes reported to be associated with LVNC morphogenesis and possible pathologies to understand the diverse spectrum between genotype and phenotype in LVNC. Also, the latest findings and issues related to the diagnosis of LVNC were summarized.

Methods

This article is written as a commentary narrative review and will provide an update on the current literature and available data on common forms of LVNC published in the past 30 years in English through to May 2022 using PubMed.

Key Content and Findings

Familial forms of LVNC are frequent, and autosomal dominant mode of inheritance has been predominantly observed. Several of the candidate causative genes are also mutated in other cardiomyopathies, suggesting a possible shared molecular and/or cellular etiology. The most common gene functions were sarcomere function whereas genes in mice LVNC models were involved in heart development. Echocardiography and cardiac magnetic resonance imaging (CMR) are useful for diagnosis although there are no unified criteria due to overdiagnosis of imaging, poor consistency between techniques, and lack of association between trabecular severity and adverse clinical outcomes.

Conclusions

This review reflects the current lack of clarity regarding the pathogenesis and significance of LVNC and showed the complexity of imaging diagnostic criteria, interpretation of the role of LVNC as a cause, and uncertainty regarding the specific genetic basis of LVNC.

Left Ventricular Non-Compaction Cardiomyopathy-Still More Questions than Answers

Left ventricular non-compaction (LVNC) describes the phenotypical phenomena characterized by the presence of excessive trabeculation of the left ventricle which forms a deep recess filled with blood. Considering the lack of a uniform definition of LVNC as well as the "golden standard" it is difficult to estimate the actual incidence of the disease, however, seems to be overdiagnosed, due to unspecific diagnostic criteria. The non-compacted myocardium may appear both as a disease representation or variant of the norm or as an adaptive phenomenon. This article covers different approaches to incidence, pathogenesis, diagnostics, and treatment of LVNC as well as recommendations for patients during follow-up.

Thromboembolic events in left ventricular non-compaction: comparison between children and adults - a systematic review and meta-analysis

Objective

Left ventricular non-compaction (LVNC) is morphologically characterised by excessive trabeculations and deep recesses in the ventricular wall. The risk of thromboembolic disease in the paediatric patients with LVNC has not been clearly established. We conducted this systematic review to evaluate the prevalence and incidence of thromboembolism (TE) in paediatric and adult patients with LVNC and searched for risk factors for TE to explore management strategies.

Methods

The primary outcome was the prevalence and incidence of TE in the patients with LVNC. The secondary outcome was the TE and mortality and heart transplantation rates between paediatric and adult patients with LVNC. We searched for studies published in MEDLINE, Embase and Cochrane Central Register of Controlled Trials between January 1950 and December 2020. A systematic search of keywords related to LVNC, anticoagulants/antiplatelets and TE was conducted. Studies that did not present original research, non-human studies, duplicated studies were excluded.

Results

Fifty-seven studies met the inclusion criteria. A total of 726 paediatric and 3862 adult patients were included. The mean prevalence rates of TE in the paediatric and adult patients with LVNC were 2.6% and 6.2% (I²=0%; p<0.450 and I²=73.7%; p<0.001), respectively. The mean annual incidences of TE in paediatric and adult patients with LVNC were 1.4% and 2.9% (I²=99.4%; p<0.001 and I²=99.5%; p<0.001), respectively. Multivariate logistic regression analysis showed that TE was associated with left ventricular ejection fraction in <40% of paediatric patients (OR, 9.47; 95% CI, 1.35 to 188.23; p=0.0225).

Conclusions

The prevalence and incidence rates in paediatric patients were lower than those in adult patients. TE was associated with a reduced systolic function in paediatric patients with LVNC.

Left Ventricular Non-Compaction Spectrum in Adults and Children: From a Morphological Trait to a Structural Muscular Disease

Left ventricular non-compaction (LVNC) is an extremely heterogeneous disorder with a highly variable clinical presentation, morphologic appearance at imaging testing, and prognosis. It is still unclear whether LVNC should be classified as a separate cardiomyopathy or if it is a mere morphological trait shared by many phenotypically distinct cardiomyopathies. Moreover, the hypertrabeculated phenotype may be reversible in some cases, possibly reflecting the left ventricular physiological response of the cardiac muscle to chronic overload. The current diagnostic criteria have several limitations, leaving many patients in a grey area. Here, we review the available literature on LVNC in order to provide an overview of the current knowledge on this complex disorder.

Left Ventricular Noncompaction Is Associated with Valvular Regurgitation and a Variety of Arrhythmias

Left ventricular noncompaction (LVNC) is a type of cardiomyopathy characterized anatomically by prominent ventricular trabeculation and deep intertrabecular recesses. The mortality associated with LVNC ranges from 5% to 47%. The etiology of LVNC is yet to be fully understood, although decades have passed since its recognition as a clinical entity globally. Furthermore, critical questions, i.e., whether LVNC represents an acquired pathology or has a congenital origin and whether the reduced contractile function in LVNC patients is a cause or consequence of noncompaction, remain to be addressed. In this study, to answer some of these questions, we analyzed the clinical features of LVNC patients. Out of 9582 subjects screened for abnormal cardiac functions, 45 exhibit the characteristics of LVNC, and 1 presents right ventricular noncompaction (RVNC). We found that 40 patients show valvular regurgitation, 39 manifest reduced systolic contractions, and 46 out of the 46 present different forms of arrhythmias that are not restricted to be caused by the noncompact myocardium. This retrospective examination of LVNC patients reveals some novel findings: LVNC is associated with regurgitation in most patients and arrhythmias in all patients. The thickness ratio of the trabecular layer to compact layer negatively correlates with fractional shortening, and reduced contractility might result from LVNC. This study adds evidence to support a congenital origin of LVNC that might benefit the diagnosis and subsequent characterization of LVNC patients.

Comparison of cardiovascular magnetic resonance characteristics and clinical prognosis in left ventricular noncompaction patients with and without arrhythmia

BACKGROUND

Left ventricular noncompaction (LVNC) is a rare type of cardiomyopathy, and one of its clinical manifestations is arrhythmia. Cardiovascular magnetic resonance (CMR) is valuable for the diagnosis and prognosis of LVNC. However, studies are lacking on the use of CMR for LVNC patients with arrhythmia. This study aimed to characterize and compare CMR features and prognosis in LVNC patients with and without arrhythmia.

METHODS

Eighty-four LVNC patients diagnosed by CMR were enrolled retrospectively in this study. Clinical data, arrhythmia characteristics, and CMR parameters were collected. Patients were divided into different groups according to the arrhythmia characteristics and CMR manifestations for statistical analysis and comparison. Ventricular tachycardia (VT), ventricular fibrillation (Vf), ventricular flutter (VFL), III° atrioventricular block (III° AVB), Wolff-Parkinson-White syndrome (WPW) and ventricular escape (VE) were defined as malignant arrhythmias and benign arrhythmias included premature ventricular contraction, atrial premature beats, atrial fibrillation, supraventricular tachycardia, supraventricular premature beat, bundle branch block, atrial flutter and sinus tachycardia. The outcome events were defined as a composition event of cardiac death, rehospitalization for heart failure, heart transplantation, and implantation of an implantable cardioverter defibrillator (ICD).

RESULTS

Sixty-seven LVNC patients (79.76%) mainly presented with arrhythmia, including premature ventricular beat (33 patients [27.73%]), bundle branch block (14 patients [11.77%]), electrocardiogram waveform changes (18 patients [15.13%]), and ventricular tachycardia (11 patients [9.24%]). The cardiac function and structure parameters had no significant difference among the nonarrhythmia group, benign arrhythmia group, and malignant arrhythmia group. However, the presence of late gadolinium enhancement (LGE) was higher in the malignant arrhythmia group than in the other two groups (p = 0.023). At a mean follow-up of 46 months, cardiac events occurred in twenty-three patients (46.94%). Kaplan-Meier analysis showed that there was no statistically significant difference in prognosis among the nonarrhythmia, benign, and malignant arrhythmia groups, but the patients with arrhythmia and association with LGE + or left ventricular ejection fraction (LVEF) < 30% had a higher risk than patients with LGE- or LVEF > 30% (LGE +, HR = 4.035, 95% CI 1.475-11.035; LVEF < 30%, HR = 8.131, 95% CI 1.805-36.636; P < 0.05).

CONCLUSIONS

In LVNC patients, the types of arrhythmias are numerous and unrepresentative, and arrhythmia is not the prognostic factor. Arrhythmia combined with presence of LGE or LVEF < 30% is associated with poor prognosis in LVNC patients.

Reversal of systolic dysfunction in noncompaction and Wolff-Parkinson-White syndrome after accessory pathway ablation

In a previously healthy asymptomatic 18-year old male, Wolff-Parkinson-White syndrome (WPW) with left ventricular hypertrabeculation/noncompaction (LVHT) and systolic dysfunction was detected. Holter monitoring disclosed multiple long episodes of supraventricular tachycardia with a heart rate of about 110/min. After radiofrequency ablation of an epicardial posteroseptal accessory pathway with ante- and retrograde conduction, systolic function gradually normalized without any pharmacotherapy. After 32 months of follow-up, the patient remains asymptomatic with normal systolic function. WPW-induced tachycardiomyopathy may even occur in asymptomatic patients, who are so adapted to their arrhythmias that they do not recognize them. <Learning objective: Tachycardiomyopathy in Wolff-Parkinson-White syndrome may even occur in asymptomatic patients. They seem so adapted to their tachyarrhythmia that they do not recognize them. Radiofrequency ablation of the accessory pathway may lead to complete normalization of systolic function. If left ventricular hypertrabeculation/noncompaction in the presented patient is causal or a coincidence remains unknown. Genetic testing revealed no variants. Because of left ventricular hypertrabeculation/noncompaction cardiologic follow-up is indicated.>.

A proposed strategy for anticoagulation therapy in noncompaction cardiomyopathy

Noncompaction cardiomyopathy (NCCM) is a rare condition characterized by prominent trabeculae, deep intertrabecular recesses, and a left ventricular myocardium with a two‐layered structure, characterized by a spongy endocardial layer and a thinner and compacted epicardial one. NCCM can be isolated or associated with other congenital heart diseases and complex syndromes involving neuromuscular disorders and facial dysmorphisms. To date, more than 40 genes coding for sarcomeric, cytoskeletal, ion channels, and desmosomal proteins have been identified. Clinical presentation is also highly variable, ranging from no symptoms to end‐stage heart failure (HF), lethal arrhythmias, sudden cardiac death, or thromboembolic events. In particular, the prevalence of thromboembolism in NCCM patients appears to be higher than that of a similar, age‐matched population without NCCM. Thromboembolism has a multifactorial aetiology, which is linked to genetic, as well as traditional cardiovascular risk factors. In previous studies, atrial fibrillation (AF) was observed in approximately 25–30% of adult NCCM patients and embolism had a cardiac source in ~63–69% of cases; therefore, AF represents a strong predictor of adverse events, especially if associated to HF and neuromuscular disorders. Left ventricular dysfunction is another risk factor for thromboembolism, as a result of blood stagnation and local myocardial injury. Moreover, it is not completely clarified if the presence of deep intertrabecular recesses causing stagnant blood flow can constitute per se a thrombogenic substrate even in absence of ventricular dysfunction. For the clinical management of NCCM patients, an appropriate stratification of the thromboembolic risk is of utmost importance for a timely initiation of anticoagulant therapy. The aim of the present study is to review the available literature on NCCM with particular attention on thromboembolic risk stratification and prevention and the current evidence for oral anticoagulation therapy. The use of direct oral anticoagulants vs. vitamin K antagonists is also discussed with important implications for patient treatment and prognosis.

Ventricular arrhythmia management in patients with genetic cardiomyopathies

Genetic cardiomyopathies are associated with increased risk for cardiac arrhythmias and sudden cardiac death. The management of ventricular arrhythmias (VAs) in patients with these conditions can be nuanced due to particular disease-based considerations, yet data specifically addressing management in these patients are limited. Here we describe the current evidence-based approach to the management of ventricular rhythm disorders in patients with genetic forms of cardiomyopathy, namely, hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, left ventricular noncompaction, and Brugada syndrome, including recommendations from consensus guideline statements when available.

Higher spatial resolution improves the interpretation of the extent of ventricular trabeculation

The ventricular walls of the human heart comprise an outer compact layer and an inner trabecular layer. In the context of an increased pre-test probability, diagnosis left ventricular noncompaction cardiomyopathy is given when the left ventricle is excessively trabeculated in volume (trabecular vol >25% of total LV wall volume) or thickness (trabecular/compact (T/C) >2.3). Here, we investigated whether higher spatial resolution affects the detection of trabeculation and thus the assessment of normal and excessively trabeculated wall morphology. First, we screened left ventricles in 1112 post-natal autopsy hearts. We identified five excessively trabeculated hearts and this low prevalence of excessive trabeculation is in agreement with pathology reports but contrasts the prevalence of approximately 10% of the population found by in vivo non-invasive imaging. Using macroscopy, histology and low- and high-resolution MRI, the five excessively trabeculated hearts were compared with six normal hearts and seven abnormally trabeculated and excessive trabeculation-negative hearts. Some abnormally trabeculated hearts could be considered excessively trabeculated macroscopically because of a trabecular outflow or an excessive number of trabeculations, but they were excessive trabeculation-negative when assessed with MRI-based measurements (T/C <2.3 and vol <25%). The number of detected trabeculations and T/C ratio were positively correlated with higher spatial resolution. Using measurements on high resolution MRI and with histological validation, we could not replicate the correlation between trabeculations of the left and right ventricle that has been previously reported. In conclusion, higher spatial resolution may affect the sensitivity of diagnostic measurements and in addition could allow for novel measurements such as counting of trabeculations.

Clinical Characteristics and Prognosis of Fetal Left Ventricular Noncompaction in Japan

BACKGROUND

Left ventricular noncompaction (LVNC) is morphologically characterized by numerous prominent trabeculations and a severely thickened, two-layered myocardium. The fetal onset of LVNC has rarely been described.Methods and Results:We conducted nationwide retrospective surveys on fetal cardiomyopathy (CM) in Japan from 2010 to 2016, from which 38 fetal patients with CM were enrolled, including 16 patients with LVNC. The rate of diagnostic concordance was 56.3% between fetal and postnatal visits in LVNC patients. The increase in the ratio of noncompacted to compacted (N/C) myocardium was time-dependent throughout the fetal period till birth (LV lateral: 1.6±0.1 to 2.8±0.2; LV apex: 2.0±0.1 to 3.2±0.2). Of all fetuses, 16 (42.1%) died or underwent heart transplantation (HT), with 3 intrauterine deaths. Lower fetal cardiovascular profile score (odds ratio, 26.9; P=0.0266) was a risk factor for death or HT. N/C ratio ≥1.6 at the apex at the first visit was a significant predictor of LVNC (odds ratio, 47.8; P=0.0113).

CONCLUSIONS

This is the first study to reveal the etiology of fetal CM based on results from a nationwide survey in Japan, highlighting the difficulty of diagnosing LVNC in fetal patients. To better understand and manage fetal CM, novel diagnostic criteria of LVNC in fetus should be established.

Hypertrabeculation; a phenotype with Heterogeneous etiology

Left ventricular hypertrabeculation (LVHT) is a phenotype with multiple etiologies and variable clinical presentation and significance. It is characterized by a 2-layer myocardium with an enlarged trabecular layer and a thinner compacted layer. The prevalence has been increasing due to advances in cardiac imaging. Initial attention was focused on the congenital noncompaction syndrome, and the presence of LVHT was always attributed to this etiology. However, due to the lack of consensus diagnostic criteria, LVHT has now been reported in a broad spectrum of cardiomyopathies, congenital heart diseases, monogenetic disorders, neuromuscular diseases, and even healthy individuals. LVHT is often associated with systolic dysfunction, arrhythmias, and thromboembolic events. Given the etiologic heterogeneity, the prognosis and outcomes are primarily determined by comorbidities, and treatment is dictated by known guidelines. We present hypertrabeculation (HT) as a phenotype and discuss the varied landscape in the classification, etiology, diagnosis, and management of the condition.

Ventricular non-compaction review

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare and unclassified cardiomyopathy that carries the potential to cause heart failure, arrhythmias, and embolic events within adults. The diagnosis of this cardiomyopathy can be based off a variety of echocardiographic, cardiac magnetic resonance (CMR), and computed tomography (CT) imaging criteria; none of which have been standardized to establish a firm diagnosis. This is further complicated by the observation from prior studies that LVNC may present as different forms of cardiomyopathy, each with its own subset of nuances that may change treatment strategies. Management of such cardiomyopathy has been debated in terms of anticoagulation, electrophysiologic studies to prevent arrhythmia, as well as heart failure prevention. Not enough data exists in regard to establishing firm guidelines for management. The following article aims to provide a comprehensive review in regard to the etiologies, pathogenesis, diagnostic criteria, management, and treatment of LVNC.

Electrophysiologic and electroanatomic characterization of ventricular arrhythmias in non-compaction cardiomyopathy: A systematic review

BACKGROUND

Non-compaction cardiomyopathy (NCCM) is a form of structural heart disease prone to ventricular arrhythmias (VAs) and sudden cardiac death. Non-compacted myocardium may harbor VA substrate, though some reports suggest otherwise.

OBJECTIVE

This study aimed to characterize the electrophysiologic (EP) features of VA in NCCM.

METHODS

We performed a systematic review of case reports, case series, and observational studies.

RESULTS

One hundred and thirty-five cases of NCCM from studies between 2000 and 2020 were included. Mean age was 34 ± 20 years, mean left ventricular (LV) ejection fraction was 42 ± 15% with two cases having late gadolinium enhancement on magnetic resonance imaging. The LV apex was the most common non-compacted segment (86%); 10% involved the right ventricle (RV). Antiarrhythmic failure was documented in 16 cases, of which 50% failed more than one agent. Only 23% of monomorphic VAs localized to regions of non-compaction on electrocardiogram. Most frequently, VAs localized to the RV outflow tract (n = 21), posterior fascicle (n = 19), and anterolateral LV apex (n = 9). All cases with apical exits arose from the non-compacted myocardium. On EPS, 83% of sustained VTs were due to re-entry, 17% due to focal mechanism. Catheter ablation was performed in 39 cases, with 7 requiring more than 1 procedure. Acute VA non-inducibility was achieved in 82% and VA-free survival was reported in 85% over a mean follow-up of 24 months.

CONCLUSION

The majority of VAs in NCCM arise remotely from non-compacted myocardium, and non-re-entrant mechanism seen in ~1/5th of sustained VTs. Catheter ablation outcomes appear favorable. Further study is needed to understand the pathophysiology of VA in NCCM.

State-of-the art review: Noncompaction cardiomyopathy in pediatric patients

Noncompaction cardiomyopathy (NCCM) is a disease characterized by hypertrabeculation, commonly hypothesized due to an arrest in compaction during fetal development. In 2006, NCCM was classified as a distinct form of cardiomyopathy (CMP) by the American Heart Association. NCCM in childhood is more frequently familial than when diagnosed in adulthood and is associated with other congenital heart diseases (CHDs), other genetic CMPs, and neuromuscular diseases (NMDs). It is yet a rare cardiac diseased with an estimated incidence of 0.12 per 100.000 in children up to 10 years of age. Diagnosing NCCM can be challenging due to non-uniform diagnostic criteria, unawareness, presumed other CMPs, and presence of CHD. Therefore, the incidence of NCCM in children might be an underestimation. Nonetheless, NCCM is the third most common cardiomyopathy in childhood and is associated with heart failure, arrhythmias, and/or thromboembolic events. This state-of-the-art review provides an overview on pediatric NCCM. In addition, we discuss the natural history, epidemiology, genetics, clinical presentation, outcome, and therapeutic options of NCCM in pediatric patients, including fetuses, neonates, infants, and children. Furthermore, we provide a simple classification of different forms of the disease. Finally, the differences between the pediatric population and the adult population are described.

Barth syndrome cardiomyopathy: targeting the mitochondria with elamipretide

Barth syndrome (BTHS) is a rare, X-linked recessive, infantile-onset debilitating disorder characterized by early-onset cardiomyopathy, skeletal muscle myopathy, growth delay, and neutropenia, with a worldwide incidence of 1/300,000-400,000 live births. The high mortality rate throughout infancy in BTHS patients is related primarily to progressive cardiomyopathy and a weakened immune system. BTHS is caused by defects in the TAZ gene that encodes tafazzin, a transacylase responsible for the remodeling and maturation of the mitochondrial phospholipid cardiolipin (CL), which is critical to normal mitochondrial structure and function (i.e., ATP generation). A deficiency in tafazzin results in up to a 95% reduction in levels of structurally mature CL. Because the heart is the most metabolically active organ in the body, with the highest mitochondrial content of any tissue, mitochondrial dysfunction plays a key role in the development of heart failure in patients with BTHS. Changes in mitochondrial oxidative phosphorylation reduce the ability of mitochondria to meet the ATP demands of the human heart as well as skeletal muscle, namely ATP synthesis does not match the rate of ATP consumption. The presence of several cardiomyopathic phenotypes have been described in BTHS, including dilated cardiomyopathy, left ventricular noncompaction, either alone or in conjunction with other cardiomyopathic phenotypes, endocardial fibroelastosis, hypertrophic cardiomyopathy, and an apical form of hypertrophic cardiomyopathy, among others, all of which can be directly attributed to the lack of CL synthesis, remodeling, and maturation with subsequent mitochondrial dysfunction. Several mechanisms by which these cardiomyopathic phenotypes exist have been proposed, thereby identifying potential targets for treatment. Dysfunction of the sarcoplasmic reticulum Ca2+-ATPase pump and inflammation potentially triggered by circulating mitochondrial components have been identified. Currently, treatment modalities are aimed at addressing symptomatology of HF in BTHS, but do not address the underlying pathology. One novel therapeutic approach includes elamipretide, which crosses the mitochondrial outer membrane to localize to the inner membrane where it associates with cardiolipin to enhance ATP synthesis in several organs, including the heart. Encouraging clinical results of the use of elamipretide in treating patients with BTHS support the potential use of this drug for management of this rare disease.

The mitral regurgitation effects of cardiac structure and function in left ventricular noncompaction

This study evaluated the effects of mitral regurgitation (MR) on cardiac structure and function in left ventricular noncompaction (LVNC) patients. The clinical and cardiovascular magnetic resonance (CMR) data for 182 patients with noncompaction or hypertrabeculation from three institutes were retrospectively included. We analyzed the difference in left ventricular geometry, cardiac function between LVNC patients with and without MR. The results showed that patients with MR had a worse New York Heart Association (NYHA) class and a higher incidence of arrhythmia (P < 0.05). MR occurred in 48.2% of LVNC patients. Compared to LVNC patients without MR, the two-dimensional sphericity index, maximum/minimum end-diastolic ratio and longitudinal shortening in LVNC patients with MR were lower (P < 0.05), and the peak longitudinal strain (PLS) of the global and segmental myocardium were obviously reduced (P < 0.05). No significant difference was found in strain in LVNC patients with different degree of MR; end diastolic volume, end systolic volume, and global PLS were statistically associated with MR and NYHA class (P < 0.05), but the non-compacted to compacted myocardium ratio had no significant correlation with them. In conclusion, the presence of MR is common in LVNC patients. LVNC patients with MR feature more severe morphological and functional changes. Hypertrabeculation is not an important factor affecting structure and function at the heart failure stage.

Left Ventricular Noncompaction: Diagnostic Approach, Prognostic Evaluation, and Management Strategies

Left ventricular noncompaction cardiomyopathy is a heart disease with relevant potential complications including heart failure, life-threatening arrhythmias, and embolic events. In order to prevent adverse outcomes, it is crucial to appropriately recognize and manage this cardiomyopathy. In this paper, we report the main clinical presentations and imaging modalities used for diagnosis, including echocardiography and magnetic resonance imaging. We highlight the role of a comprehensive functional cardiac evaluation and the possible prognostic implications of both systolic and diastolic dysfunction. Furthermore, we summarize clinical factors and imaging findings which have prognostic significance. Finally, we discuss the main management strategies based on phenotypic expressions which are aimed at treating symptoms and preventing complications.

Neurological complications of cardiomyopathies

There is a multifaceted relationship between the cardiomyopathies and a wide spectrum of neurological disorders. Severe acute neurological events, such as a status epilepticus and aneurysmal subarachnoid hemorrhage, may result in an acute cardiomyopathy the likes of Takotsubo cardiomyopathy. Conversely, the cardiomyopathies may result in a wide array of neurological disorders. Diagnosis of a cardiomyopathy may have already been established at the time of the index neurological event, or the neurological event may have prompted subsequent cardiac investigations, which ultimately lead to the diagnosis of a cardiomyopathy. The cardiomyopathies belong to one of the many phenotypes of complex genetic diseases or syndromes, which may also involve the central or peripheral nervous systems. A number of exogenous agents or risk factors such as diphtheria, alcohol, and several viruses may result in secondary cardiomyopathies accompanied by several neurological manifestations. A variety of neuromuscular disorders, such as myotonic dystrophy or amyloidosis, may demonstrate cardiac involvement during their clinical course. Furthermore, a number of genetic cardiomyopathies phenotypically incorporate during their clinical evolution, a gamut of neurological manifestations, usually neuromuscular in nature. Likewise, neurological complications may be the result of diagnostic procedures or medications for the cardiomyopathies and vice versa. Neurological manifestations of the cardiomyopathies are broad and include, among others, transient ischemic attacks, ischemic strokes, intracranial hemorrhages, syncope, muscle weakness and atrophy, myotonia, cramps, ataxia, seizures, intellectual developmental disorder, cognitive impairment, dementia, oculomotor palsies, deafness, retinal involvement, and headaches.

A burden of sarcomere gene variants in fetal-onset patients with left ventricular noncompaction

BACKGROUND

Left ventricular noncompaction (LVNC) is a hereditary cardiomyopathy, associated with high morbidity and mortality, but the role of genetics in cases of fetal-onset has not been fully evaluated. The goal of this study was to identify the genetic background in LVNC fetal-onset patients using next-generation sequencing (NGS).

METHODS

Thirty-three fetal-onset Japanese probands with LVNC (20 males and 13 females) were enrolled. In the enrolled patients, 81 genes associated with cardiomyopathy were screened using next-generation sequencing (NGS) retrospectively.

RESULTS

Twenty-three patients had congestive heart failure (CHF), and six patients had arrhythmias. Prominent trabeculations were mostly observed in lateral LV, posterior LV, and apex of LV in patients with LVNC. Twelve died; three patients experienced intrauterine death or termination of pregnancy. Overall, 15 variants were found among eight genes in 16 patients. Seven variants were detected in MYH7 and two in TPM1. Sarcomere gene variants accounted for 75.0%. A multivariable proportional hazards model revealed that CHF at diagnosis and a higher ratio of the noncompacted layer/compacted layer in the LV posterior wall were independent risk factors for death in LVNC fetal-onset patients (odds ratio = 4.26 × 10⁶ and 1.36 × 10⁸, p = 0.0075 and 0.0005, respectively).

CONCLUSIONS

The present study is the first report focusing on genetic background combined with clinical features in LVNC fetal-onset patients using NGS. Sarcomere variants were most commonly identified in fetal-onset patients, and greater attention should be paid to fetal-onset patients with LVNC having prominent trabeculations in the LV because they are more likely to develop CHF.

Do children with left ventricular noncompaction and a noncompaction-to-compaction ratio < 2 have a better prognosis?

Background

Ultrasonography is commonly used to diagnose left ventricular noncompaction (LVNC). A ratio of noncompacted to compacted myocardium (NC/C ratio) > >2 is often used to diagnose LVNC. However, a large proportion of patients with noncompact myocardium have NC/C < 2, and the prognosis of these patients have not been studied.

Methods

We included children diagnosed with LVNC between 0 and 15 years of age from January 2007 to December 2018. LVNC was diagnosed based on Stöllberger standard when over three trabeculae were found to be associated with the interventricular recesses. A maximal end systolic ratio of noncompacted to compacted layers was NC/C ratio. Outcomes for LVNC subjects with NC/C < 2 and NC/C > 2 were compared using Kaplan-Meier methods.

Results

There were 124 newly diagnosed LVNC cases, classified as isolated (i-LVNC, n = 47) or non-isolated (ni-LVNC, n = 77) LVNC and NC/C > 2 (n = 43) or < 2 (n = 81). The median (interquartile range) follow-up duration was 12 (3–30) months for all patients and 16 (6–36) months for survivors. Sixteen patients with i-LVNC died during follow-up. Patients with i-LVNC and NC/C > 2 had worse survival than those with NC/C < 2 (p = 0.022).

Conclusions

In conclusion, during a 12-month follow-up, patients with i-LVNC with NC/C < 2 had a benign prognosis and better outcomes than those with NC/C > 2, suggesting that the former could have a more active and routine lifestyle.

The role of multimodality imaging in the diagnosis of left ventricular noncompaction

Left ventricular noncompaction (LVNC) is a heterogeneous entity and, in reality, a likely spectrum of disease which is clinically associated with arrhythmia, thromboembolic complications and sudden cardiac death. With the emergence of cardiac MRI (cMRI), the phenotype is increasingly more prevalent, resulting in clinical uncertainty regarding prognosis and management. The currently accepted hypothesis suggests an early embryonic arrest of the normal, sequential myocardial compaction process. LVNC is observed in isolation or in association with congenital heart disease, neuromuscular disease or a vast array of genetic cardiomyopathies. Definition of the entity varies among international society guidelines with differences both within and between imaging modalities, predominantly echocardiography and cMRI. Long-term prognostic data are emerging but due to the intrinsic variability in reported prevalence, selection bias and lack of pathological to prognostic correlation, there are many uncertainties regarding clinical management. This review seeks to clarify the role of multimodality imaging in diagnosis and management of the disease. We discuss the sensitivity and specificity of the current diagnostic criteria, as well as the nuances in diagnosis using the available imaging modalities.

Atrial fibrillation in patients with inherited cardiomyopathies

Atrial fibrillation (AF) often complicates the course of inherited cardiomyopathies and, in some cases, may be the presenting feature. Each inherited cardiomyopathy has its own peculiar pathogenetic characteristics that can contribute to the development and maintenance of AF. Atrial fibrillation may occur as a consequence of disease-specific defects, non-specific cardiac chamber changes secondary to the primary illness, or a combination thereof. The presence of AF can denote a turning point in the progression of the disease, promoting clinical deterioration and increasing morbidity and mortality. Furthermore, the management of AF can be particularly challenging in patients with inherited cardiomyopathies. In this article, we review the current information on the prevalence, pathophysiology, risk factors, and treatment of AF in three different inherited cardiomyopathies: hypertrophic cardiomyopathy, arrhythmogenic right ventricular dysplasia/cardiomyopathy, familial dilated cardiomyopathy, and left ventricular non-compaction cardiomyopathy.

Characterization of Left Ventricular Non-Compaction Cardiomyopathy

Left ventricle non-compaction cardiomyopathy (LVNC) has gained great interest in recent years, being one of the most controversial cardiomyopathies. There are several open debates, not only about its genetic heterogeneity, or about the possibility to be an acquired cardiomyopathy, but also about its possible overdiagnosis based on imaging techniques. In order to better understand this entity, we identified 38 LVNC patients diagnosed by cardiac MRI (CMRI) or anatomopathological study that could underwent NGS-sequencing and clinical study. Anatomopathological exam was performed in eight available LVNC hearts. The genetic yield was 34.2%. Patients with negative genetic testing had better left ventricular ejection fraction (LVEF) or it showed a tendency to improve in follow-up, and a possible trigger factor for LVNC was identified in 1/3 of them. Nonetheless, cerebrovascular accidents occurred in similar proportions in both groups. We conclude that in LVNC there seem to be different ways to achieve the same final phenotype. Genetic testing has a good genetic yield and provides valuable information. LVNC without an underlying genetic cause may have a better prognosis in terms of LVEF evolution. However, anticoagulation to prevent cerebrovascular accident (CVA) should be carefully evaluated in all patients. Larger series with pathologic examination are needed to help better understand this entity.

Increased Burden of Ion Channel Gene Variants Is Related to Distinct Phenotypes in Pediatric Patients With Left Ventricular Noncompaction

BACKGROUND

Left ventricular noncompaction (LVNC) is a hereditary type of cardiomyopathy. Although it is associated with high morbidity and mortality, the related ion channel gene variants in children have not been fully investigated. This study aimed to elucidate the ion channel genetic landscape of LVNC and identify genotype-phenotype correlations in a large Japanese cohort.

METHODS

We enrolled 206 children with LVNC from 2002 to 2017 in Japan. LVNC was classified as follows: LVNC with congenital heart defects, arrhythmia, dilated phenotype, or normal function. In the enrolled patients, 182 genes associated with cardiomyopathy were screened using next-generation sequencing.

RESULTS

We identified 99 pathogenic variants in 40 genes in 87 patients. Of the pathogenic variants, 8.8% were in genes associated with channelopathies, 27% were in sarcomere genes, and 11.5% were in mitochondrial genes. Ion channel gene variants were mostly associated with the arrhythmia classification, whereas sarcomere and mitochondrial gene variants were associated with the dilated phenotype. Echocardiography revealed that the group with ion channel gene variants had almost normal LV ejection fraction and LV diastolic diameter Z scores. Fragmented QRS, old age, and an arrhythmia phenotype were the most significant risk factors for ventricular tachycardia (P=0.165, 0.0428, and 0.0074, respectively). Moreover, the group with ion channel variants exhibited a greater risk of a higher prevalence of arrhythmias such as ventricular tachycardia, rather than congestive heart failure.

CONCLUSIONS

This is the first study that focused on genotype-phenotype correlations in a large pediatric LVNC patient cohort with ion channel gene variants that were determined using next-generation sequencing. Ion channel gene variants were strongly correlated with arrhythmia phenotypes. Genetic testing and phenotype specification allow for appropriate medical management of specific LVNC targets.

Left ventricular noncompaction, morphological, and clinical features for an integrated diagnosis

The presence of myocardial noncompaction (NC), regardless of the criterion used, does not identify cardiomyopathy per se. The distinction between a morphological variant and the presence of an NC cardiomyopathy is challenging. However, thanks to larger cohorts of patients and longer periods of follow-up, better clinical characterization and prognostic evaluation are becoming available. Indeed, the physician is required to integrate the evidence of NC with the clinical history of the patient, which is supplemented by necessary advanced instrumental investigations before a definite diagnosis of NC cardiomyopathy can be made. Therefore, we extensively revised the current literature in order to help the clinicians to identify clinical features which are pivotal supporting diagnostic element for the correct recognition of Left ventricular noncompaction cardiomyopathy and thus highlighting the difference between a form of cardiomyopathy and a mere intraventricular hypertrabeculation.

Importance of lead aVR on predicting adverse cardiac events in patients with noncompaction cardiomyopathy

Background

Noncompaction cardiomyopathy (NCCM) is a relatively rare cardiac abnormality with high rates of mortality and morbidity. T‐wave amplitudes during ventricular repolarization in lead aVR (TaVR) have been reported to be associated with the prognosis of various cardiovascular diseases. This study sought to investigate the prevalence and prognostic role of positive TaVR in patients with NCCM.

Methods

We evaluated consecutive 161 patients with NCCM (65.8% men, mean age 42.5 ± 15.2 years old). Presentation electrocardiogram was assessed regarding classical parameters as well as T‐wave amplitudes in lead aVR. The primary endpoint was defined as composite lethal arrhythmic events, including sudden cardiac death, ventricular fibrillation, or sustained ventricular tachycardia or appropriate implantable cardioverter–defibrillator shock. Heart failure requiring hospitalization, cardiovascular death, and all‐cause mortality were also investigated as secondary endpoints.

Results

Patients with positive TaVR showed higher rates for arrhythmic events, hospitalization for heart failure, and death compared with patients without it. In multivariate Cox model, after adjusting for other known clinical and electrocardiographic risk factors, the positive TaVR was found to be a strong independent predictor of primary endpoint (HR: 4.8, 95% CI: 1.2–19.3; p = .025) and all‐cause death (HR: 3.5, 95% CI: 1.0–12.1; p = .045).

Conclusion

Our findings revealed that positive TaVR is significantly and independently associated with adverse outcomes in NCCM patients. This unique ECG criterion in the often ignored lead provides incremental information beyond what is available with other traditional risk factors.

Impairment of myocardial perfusion correlates with heart failure severity in patients with non-compaction cardiomyopathy

Aims

Non‐compaction cardiomyopathy (NCM) is a congenital heart disease characterized by an arrest of the myocardial compaction process. Although NCM patients have impaired formation of microvasculature, the functional impact of these changes remains undefined. We sought to analyse a potential correlation between myocardial ischemia and heart failure severity in NCM patients.

Methods and results

We enrolled 41 NCM patients (28 male and 13 female), aged 21–70 years. In all patients, we have determined left ventricular end‐diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), and global longitudinal strain (GLS) by echocardiography. At the same time, serum levels of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) have been measured, and myocardial single‐photon emission computed tomography at rest and on stress was used to define significant myocardial ischemia defined as summed difference score ≥ 2. Myocardial ischemia has been demonstrated in 11 patients (27%, Group A), and 30 patients showed no significant ischemic changes (73%, Group B). The groups did not differ in sex, age, kidney, or liver function. When compared with Group B, Group A had significantly lower LVEF (35 ± 15% in Group A vs. 53 ± 11% in Group B, P < 0.001), higher LVEDV (188 ± 52 mL vs. 136 ± 52 mL, P = 0.007), lower GLS (−9.9 ± 5.2% vs. −14.5 ± 4.1%, P = 0.001), and higher NT‐proBNP levels (1691 ± 1883 pg/mL vs. 422 ± 877 pg/mL, P = 0.006). Overall, higher summed difference score was associated with lower LVEF (r = −0.48, P = 0.001), higher LVEDV (r = 0.39, P = 0.012), lower GLS (r = 0.352, P = 0.024), and higher levels of NT‐proBNP (r = 0.66, P < 0.001).

Conclusions

The presence of myocardial ischemia in patients with NCM is associated with worse left ventricular function, dilation of the left ventricle, and more pronounced neurohumoral activation.

Different Manifestations in Familial Isolated Left Ventricular Non-compaction: Two Case Reports and Literature Review

Left ventricular non-compaction (LVNC) is a form of cardiomyopathy characterized by prominent trabeculae and deep intertrabecular recesses which form a distinct "non-compacted" layer in the myocardium. It results from intrauterine arrest of the compaction process of the left ventricular myocardium. Clinical manifestations vary from asymptomatic to heart failure (HF), arrhythmias, or thromboembolic events. We present a case of mother and son diagnosed with isolated LVNC (ILVNC). A 4-years-old male patient, diagnosed at 3 months with ILVNC, and NYHA functional class IV HF, was admitted to the Emergency Institute for Cardiovascular Diseases and Transplantation of Targu Mures, Romania, for cardiologic reevaluation, and diagnosis confirmation. ILVNC was confirmed using echocardiography, revealing a non-compaction to compaction (NC/C) ratio of > 2.7. His evolution was stationary until the age of 8 years, when severe pneumonia caused hemodynamic decompensation, and he was listed for heart transplantation (HT). The patient underwent HT at the age of 11 years with favorable postoperative outcome. Meanwhile, a 22-years-old female patient, mother of the aforementioned patient, was also admitted to our institute due to severe fatigue, dyspnea, and recurrent palpitations with multiple implantable cardioverter defibrillator (ICD) shock delivery. Extensive medical history revealed that a presumptive ILVNC diagnosis was established when she was 11 years old. She was asymptomatic until 18 years old, when 3 months post-partum, she developed NYHA functional class III HF, and subsequently underwent ICD implantation. Her diagnosis was confirmed using multi-detector computed tomography angiography, which revealed a NC/C ratio of > 3.3. ICD adjustments were carried out with a favorable evolution under chronic drug therapy. The last evaluation, at 27 years old, revealed that she was in NYHA functional class II HF. In conclusion, ILVNC, even when familial, can present different clinical pictures and therefore requires different medical approaches.

[Left ventricular non - compaction: contemporary view of genetic background, clinical course, diagnostic and treatment]

This review highlights and discusses recent advances in understanding left ventricular non - compaction (LVNC). Clinical profile, prognosis and even diagnosis are still a great challenge faced by the world. The population prevalence of left ventricular non - compaction remains unknown. High variability of clinical manifestations, genetic heterogenity with overlap of different phenotypes, variability of hereditary patterns suggests that LVNC seems to be rather an isolated trait or a part of phenotypic expression of different cardiac diseases or complex genetic syndromes.

Systematic Review of Genotype-Phenotype Correlations in Noncompaction Cardiomyopathy

Background

A genetic cause can be identified in 30% of noncompaction cardiomyopathy patients (NCCM) with clinical features ranging from asymptomatic cardiomyopathy to heart failure with major adverse cardiac events (MACE).

Methods and Results

To investigate genotype‐phenotype correlations, the genotypes and clinical features of genetic NCCM patients were collected from the literature. We compared age at diagnosis, cardiac features and risk for MACE according to mode of inheritance and molecular effects for defects in the most common sarcomere genes and NCCM subtypes. Geno‐ and phenotypes of 561 NCCM patients from 172 studies showed increased risk in children for congenital heart defects (P<0.001) and MACE (P<0.001). In adult NCCM patients the main causes were single missense mutations in sarcomere genes. Children more frequently had an X‐linked or mitochondrial inherited defect (P=0.001) or chromosomal anomalies (P<0.001). MYH7 was involved in 48% of the sarcomere gene mutations. MYH7 and ACTC1 mutations had lower risk for MACE than MYBPC3 and TTN (P=0.001). The NCCM/dilated cardiomyopathy cardiac phenotype was the most frequent subtype (56%; P=0.022) and was associated with an increased risk for MACE and high risk for left ventricular systolic dysfunction (<0.001). In multivariate binary logistic regression analysis MYBPC3,TTN, arrhythmia ‐, non‐sarcomere non‐arrhythmia cardiomyopathy—and X‐linked genes were genetic predictors for MACE.

Conclusions

Sarcomere gene mutations were the most common cause in adult patients with lower risk of MACE. Children had multi‐systemic disorders with severe outcome, suggesting that the diagnostic and clinical approaches should be adjusted to age at presentation. The observed genotype‐phenotype correlations endorsed that DNA diagnostics for NCCM is important for clinical management and counseling of patients.

Genotype-Positive Status Is Associated With Poor Prognoses in Patients With Left Ventricular Noncompaction Cardiomyopathy

Background Left ventricular noncompaction cardiomyopathy ( LVNC ) is a genetically and phenotypically heterogeneous disease. This study aims to investigate the genetic basis and genotype-phenotype correlations in a cohort of Chinese patients with LVNC . Methods and Results A total of 72 cardiomyopathy-associated genes were comprehensively screened in 83 adults and 17 children with LVNC by targeted sequencing. Pathogenicity of the detected variants was determined according to their prevalence and American College of Medical Genetics and Genomics recommendations. Baseline and follow-up clinical data were collected. The primary end point was a composite of death and heart transplantation. Overall, 42 pathogenic variants were identified in 38 patients (38%), with TTN , MYH 7, MYBPC 3, and DSP being the most commonly involved genes. At baseline, genotype-positive adults had higher rates of atrial fibrillation and family history, and lower left ventricular ejection fraction, compared with genotype-negative adults. During a median follow-up of 4.2 years, more primary end points occurred in genotype-positive adults than in genotype-negative adults (50.0% versus 23.5%; P=0.013). Multivariable analysis demonstrated that genotype-positive status was associated with higher risks of death and heart transplantation, independent of age, sex, and cardiac function at baseline in patients with LVNC (adjusted hazards ratio, 2.49; 95% confidence interval, 1.15-5.37; P=0.020). Conclusions Our study revealed a distinct genetic spectrum in Chinese patients with LVNC , with variants in TTN , MYH 7, MYBPC 3, and DSP being the most common. The presence of pathogenic variants is an independent risk factor for adverse outcomes and may aid in risk stratification in adult patients. Larger studies are needed to confirm these findings.

Prevalence and prognostic impact of left ventricular non-compaction in patients with thalassemia

A high incidence of isolated left ventricular non-compaction (LVNC) has been reported in previous studies on smaller cohorts of patients with thalassemia by cardiac MRI but the clinical impact of the finding is unknown. This prospective cohort study evaluates the prevalence and clinical implication of the finding. Prospective cohort study with enrollment of all consecutive cases with thalassemia referred for cardiac MRI from September 2007 to November 2014. The presence of LVNC was assessed according to the Petersen method and the Jacquier method, with the proposed changes by Fazio, Grothoff, and Chiodi. A clinical follow-up was performed in all patients. We included 560 patients with thalassemia (473 with thalassemia major and 87 with thalassemia intermedia: mean age 31.9 ± 10.6 years, male/female = 250/310). A total number of 1683 MRI tests were performed. A diagnosis of LVNC was determined according to adopted MR criteria in 44 patients (7.9%). Patients with LVNC had a significantly lower ejection fraction (52.68 ± 5.17% vs. 56.90 ± 6.34%; p = 0.0005) and greater indexed LV ESV (48.16 ± 10.03 ml/m² vs. 40.02 ± 10.06 ml/m²; p = 0.0022). After a mean follow-up time was 5.1 years, no significant change of MR parameters was detected as well as no clinical adverse events. LVNC is relatively frequent in patients with thalassemia. However, it is not associated with a worsening of LV function and adverse events after a long-term follow-up.

Left ventricular noncompaction - Risk stratification and genetic consideration

Left ventricular noncompaction (LVNC) is a cardiomyopathy characterized by two layered structures composed of prominent trabecular meshwork and deep intertrabecular recesses. LVNC was thought to be rare; however, heightened awareness has resulted in an increased detection of the morphological features of LVNC in routine clinical practice especially in the adult population. Although LVNC was classified as an independent primary cardiomyopathy of genetic origin by the American Heart Association in 2006, its definition, diagnostic criteria and clinical implications are still being debated. Clinical manifestations are highly variable, even in the same family, ranging from no symptoms to disabling congestive heart failure, life-threatening arrhythmias, systemic thromboemboli, and sudden cardiac death. Among phenotypic subtypes of LVNC, children with isolated LVNC with normal cardiac function had the best outcomes: children with LVNC and dilated cardiomyopathy had the worst outcomes. Myocardial dysfunction or ventricular arrhythmias are predictors of mortality in adults with LVNC. LVNC, like other forms of inherited cardiomyopathy, is genetically heterogeneous and can be inherited as an autosomal dominant or X-linked recessive disorder. It has been linked to mutations in many genes, including ZASP, TAZ/G4.5, and those encoding sarcomeric, Z-disc, cytoskeleton proteins, and mitochondria. Disturbance of the NOTCH signaling pathway has been reported to be part of genetic pathway for LVNC as well. Although there are an increasing number of reports, genotype-phenotype correlations have been challenging and investigations are ongoing. Patients with mutations are more likely to have major adverse cardiovascular events, further, LV systolic dysfunction in mutation carriers makes them at high risk for cardiac events. Treatments focus on improvement in cardiac function and reduction of mechanical stress in patients with systolic dysfunction and on treatment of arrhythmia and implantation of an automatic implantable cardioverter-defibrillator for prevention of sudden death. Given that 20-40% of cases may be familial, family screening is recommended.

Association of Wolff-Parkinson-White With Left Ventricular Noncompaction Cardiomyopathy in Children

BACKGROUND

Wolff-Parkinson-White (WPW) has been associated with left ventricular noncompaction (LVNC) in children. Little is known about the prevalence of this association, clinical outcomes, and treatment options.

METHODS

Retrospective review of subjects with LVNC. LVNC was defined by established criteria; those with congenital heart disease were excluded. Electrocardiograms (ECGs) were reviewed for presence of pre-excitation. Outcomes were compared between those with isolated LVNC and those with WPW and LVNC.

RESULTS

A total of 348 patients with LVNC were identified. Thirty-eight (11%) were found to have WPW pattern on ECG, and 84% of those with WPW and LVNC had cardiac dysfunction. In Kaplan-Meier analysis, there was significantly lower freedom from significant dysfunction (ejection fraction ≤ 40%) among those with WPW and LVNC (P < .001). Further analysis showed a higher risk of developing significant dysfunction in patients with WPW and LVNC versus LVNC alone (hazard ratio 4.64 [2.79, 9.90]). Twelve patients underwent an ablation procedure with an acute success rate of 83%. Four patients with cardiac dysfunction were successfully ablated, 3 having improvement in function.

CONCLUSION

WPW is common among children with LVNC and is associated with cardiac dysfunction. Ablation therapy can be safely and effectively performed and may result in improvement in function.

Long-Term Outcomes of Childhood Left Ventricular Noncompaction Cardiomyopathy: Results From a National Population-Based Study

BACKGROUND

Long-term outcomes for childhood left ventricular noncompaction (LVNC) are uncertain. We examined late outcomes for children with LVNC enrolled in a national population-based study.

METHODS

The National Australian Childhood Cardiomyopathy Study includes all children in Australia with primary cardiomyopathy diagnosed before 10 years of age between 1987 and 1996. Outcomes for subjects with LVNC with a dilated phenotype (LVNC-D) were compared with outcomes for those with dilated cardiomyopathy. Propensity-score analysis was used for risk factor adjustment.

RESULTS

There were 29 subjects with LVNC (9.2% of all cardiomyopathy subjects), with a mean annual incidence of newly diagnosed cases of 0.11 per 100 000 at-risk individuals. Congestive heart failure was the initial symptom in 24 of 29 subjects (83%), and 27 (93%) had LVNC-D. The median age at diagnosis was 0.3 (interquartile interval, 0.08-1.3) years. The median duration of follow-up was 6.8 (interquartile interval, 0.7-24.0) years for all subjects and 24.7 (interquartile interval, 23.3 - 27.7) years for surviving subjects. Freedom from death or transplantation was 48% (95% confidence interval [CI], 30-65) at 10 years after diagnosis and 45% (95% CI, 27-63) at 15 years. In competing-risk analysis, 21% of subjects with LVNC were alive with normal left ventricular systolic function, and 31% were alive with abnormal function at 15 years. Propensity-score matching between subjects with LVNC-D and those with dilated cardiomyopathy suggested a lower freedom from death/transplantation at 15 years after diagnosis in the subjects with LVNC-D (LVNC-D, 46% [95% CI, 26-66] versus dilated cardiomyopathy, 70% [95% CI, 42-97]; P=0.08). Using propensity-score inverse probability of treatment-weighted Cox regression, we found evidence that LVNC-D was associated with a greater risk of death or transplantation (hazard ratio, 2.3; 95% CI, 1.4-3.8; P=0.0012).

CONCLUSIONS

Symptomatic children with LVNC usually present in early infancy with a predominant dilated phenotype. Long-term outcomes are worse than for matched children with dilated cardiomyopathy.

Semaphorin 3E/PlexinD1 signaling is required for cardiac ventricular compaction

Left ventricular noncompaction (LVNC) is one of the most common forms of genetic cardiomyopathy characterized by excessive trabeculation and impaired myocardial compaction during fetal development. Patients with LVNC are at higher risk of developing left/right ventricular failure or both. Although the key regulators for cardiac chamber development are well studied, the role of semaphorin (Sema)/plexin signaling in this process remains poorly understood. In this article, we demonstrate that genetic deletion of Plxnd1, a class-3 Sema receptor in endothelial cells, leads to severe cardiac chamber defects. They were characterized by excessive trabeculation and noncompaction similar to patients with LVNC. Loss of Plxnd1 results in decreased expression of extracellular matrix proteolytic genes, leading to excessive deposition of cardiac jelly. We demonstrate that Plxnd1 deficiency is associated with an increase in Notch1 expression and its downstream target genes. In addition, inhibition of the Notch signaling pathway partially rescues the excessive trabeculation and noncompaction phenotype present in Plxnd1 mutants. Furthermore, we demonstrate that Semaphorin 3E (Sema3E), one of PlexinD1's known ligands, is expressed in the developing heart and is required for myocardial compaction. Collectively, our study uncovers what we believe to be a previously undescribed role of the Sema3E/PlexinD1 signaling pathway in myocardial trabeculation and the compaction process.

A Case of Isolated Left Ventricular Non-Compaction Cardiomyopathy in a HIV Patient Presenting With Acute Heart Failure

The etiology of cardiomyopathy in a HIV patient is multifactorial. Identifying the etiology of cardiomyopathy in a HIV patient needs extensive evaluation. Common causes include ischemic cardiomyopathy, myocarditis due to viral infections and opportunistic infections, cocaine abuse, alcoholic heart disease, drug toxicity or due to nutritional deficiencies. However, in a number of cases the etiology is unknown. We report a case of 36-year-old African American man with history of HIV who presented with acute heart failure due to left ventricular non-compaction (LVNC). Transthoracic and transesophageal echocardiogram showed significant left ventricular trabeculations and blood flow in deep recesses. Endomyocardial biopsy was suggestive of LVNC. He underwent left ventricular assist device implantation for destination therapy and subsequently cardiac transplantation. The diagnosis of LVNC is often made by echocardiogram. As LVNC could be a normal variant, a comprehensive diagnostic assessment including multimodality imaging, a systematic screening of first degree relatives, and a comprehensive clinical and genetic assessment by a multidisciplinary team may be needed to arrive at the diagnosis. Early diagnosis and timely intervention may reduce the risk of premature death in these young patients.