Advances and challenges in the diagnosis and management of left ventricular noncompaction in adults: A literature review

In the realm of cardiovascular health, isolated left ventricular noncompaction (LVNC) stands out for its distinct morphological features and the clinical challenges it presents, particularly in adults. This literature review explores the intricacies of LVNC, aiming to unravel its epidemiological spread, diagnostic hurdles, and therapeutic strategies. Despite technological advancements in cardiac imaging that have improved the recognition of LVNC, a significant gap persists alongside a fragmented understanding of its pathogenesis. The studies scrutinized reveal a broad spectrum of prevalence rates influenced by diverse diagnostic tools and demographic variables. This variation underscores the complexity of accurately identifying LVNC and the resultant implications for clinical management. The review succinctly addresses the need for precise guidelines to navigate the diagnosis of LVNC and outlines the imperative for tailored clinical management approaches that cater to the wide array of patient presentations, from asymptomatic cases to those with severe cardiac dysfunction. By highlighting the critical gaps in current literature-namely the absence of standardized diagnostic criteria and a comprehensive pathogenic model-the review sets the stage for future research directions. These endeavors are essential for enhancing diagnostic accuracy, refining management protocols, and ultimately improving patient outcomes in this complex subset of cardiomyopathy, thus contributing significantly to the advancement of cardiovascular medicine.

Accurate Classification of Non-ischemic Cardiomyopathy

PURPOSE OF REVIEW

This article aims to review the accurate classification of non-ischemic cardiomyopathy, including the methods, basis, subtype characteristics, and prognosis, especially the similarities and differences between different classifications.

RECENT FINDINGS

Non-ischemic cardiomyopathy refers to a myocardial disease that excludes coronary artery disease or ischemic injury and has a variety of etiologies and high incidence. Recent studies suggest that traditional classification methods based on primary/mixed/acquired or genetic/non-genetic cannot meet the precise needs of contemporary clinical management. This article systematically describes the history of classifications of cardiomyopathy and presents etiological and genetic differences between cardiomyopathies. The accurate classification is described from the perspective of morphology, function, and genomics in hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, left ventricular noncompaction, and partially acquired cardiomyopathy. The different clinical characteristics and treatment needs of these cardiomyopathies are elaborated. Some single-gene mutant cardiomyopathies have unique phenotypes, and some cardiomyopathies have mixed phenotypes. These special classifications require personalized precision treatment, which is worthy of independent research. This article describes recent advances in the accurate classification of non-ischemic cardiomyopathy from clinical phenotypes and causative genes, discusses the advantages and usage scenarios of each classification, compares the differences in prognosis and patient management needs of different subtypes, and summarizes common methods and new exploration directions for accurate classification.

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.

Long QT syndrome and left ventricular non-compaction in a family with KCNH2 mutation: A case report

BACKGROUND

Left ventricular non-compaction (LVNC) is an abnormality of the myocardium, characterized by prominent left ventricular trabeculae and deep inter-trabecular recesses. Long QT syndrome (LQTS) is a cardiac ion channelopathy presenting with a prolonged QT interval on resting electrocardiogram and is associated with increased susceptibility to sudden death. The association between LVNC and LQTS is uncommon.

CASE PRESENTATION

We report an Italian family with a novel pathogenic KCNH2 variant who presented with clinical features of LVNC and LQTS. The proband came to our attention after two syncopal episodes without prodromal symptoms. His ECG showed QTc prolongation and deep T wave inversion in anterior leads, and the echocardiogram fulfilled LVNC criteria. After that, also his sister was found to have LQTS and LVNC, while his father only presented LQTS.

CONCLUSIONS

Physicians should be aware of the possible association between LVNC and LQTS. Even if this association is rare, patients with LVNC should be investigated for LQTS to prevent possible severe or even life-threatening arrhythmic episodes.

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.

Noncompaction Cardiomyopathy-History and Current Knowledge for Clinical Practice

Noncompaction cardiomyopathy (NCCM) has gained increasing attention over the past twenty years, but in daily clinical practice NCCM is still rarely considered. So far, there are no generally accepted diagnostic criteria and some groups even refuse to acknowledge it as a distinct cardiomyopathy, and grade it as a variant of dilated cardiomyopathy or a morphological trait of different conditions. A wide range of morphological variants have been observed even in healthy persons, suggesting that pathologic remodeling and physiologic adaptation have to be differentiated in cases where this spongy myocardial pattern is encountered. Recent studies have uncovered numerous new pathogenetic and pathophysiologic aspects of this elusive cardiomyopathy, but a current summary and evaluation of clinical patient management are still lacking, especially to avoid mis- and overdiagnosis. Addressing this issue, this article provides an up to date overview of the current knowledge in classification, pathogenesis, pathophysiology, epidemiology, clinical manifestations and diagnostic evaluation, including genetic testing, treatment and prognosis of NCCM.

Clinical Insights Into Heritable Cardiomyopathies

Cardiomyopathies (CMs) encompass a heterogeneous group of structural and functional abnormalities of the myocardium. The phenotypic characteristics of these myocardial diseases range from silent to symptomatic heart failure, to sudden cardiac death due to malignant tachycardias. These diseases represent a leading cause of cardiovascular morbidity, cardiac transplantation, and death. Since the discovery of the first locus associated with hypertrophic cardiomyopathy 30 years ago, multiple loci and molecular mechanisms have been associated with these cardiomyopathy phenotypes. Conversely, the disparity between the ever-growing landscape of cardiovascular genetics and the lack of awareness in this field noticeably demonstrates the necessity to update training curricula and educational pathways. This review summarizes the current understanding of heritable CMs, including the most common pathogenic gene variants associated with the morpho-functional types of cardiomyopathies: dilated, hypertrophic, arrhythmogenic, non-compaction, and restrictive. Increased understanding of the genetic/phenotypic associations of these heritable diseases would facilitate risk stratification to leveraging appropriate surveillance and management, and it would additionally provide identification of family members at risk of avoidable cardiovascular morbidity and mortality.

Case Report: Novel Likely Pathogenic ACTN2 Variant Causing Heterogeneous Phenotype in a Korean Family With Left Ventricular Non-compaction

Left ventricular non-compaction (LVNC) is a very rare primary cardiomyopathy with a genetic etiology, resulting from the failure of myocardial development during embryogenesis, and it carries a high risk of left ventricular dysfunction, thromboembolic phenomenon, and malignant arrhythmias. Here, we report the first case of familial LVNC in Korea, caused by a novel ACTN2 missense variant. We performed duo exome sequencing (ES) to examine the genome of the proband and his father. A 15-year-old boy was admitted for the evaluation of exertional dyspnea for 2 weeks. He was diagnosed with LVNC with a dilated cardiomyopathy phenotype [left ventricular end-diastolic dimension 60 mm, interventricular septal dimension 8.2 mm by transthoracic echocardiography (TTE)]. For the screening of familial cardiomyopathy, TTE and cardiac magnetic resonance imaging (cMRI) were performed, which revealed hypertrophic and isolated LVNC in the proband's father and sister, respectively. In particular, the cMRI revealed dense hypertrabeculation with focal aneurysmal changes in the apical septal wall in the proband's father. ES of the father-son duo identified a novel heterozygous c.668T>C variant of the ACTN2 gene (NM_001103.3:c.668T>C, p.Leu223Pro; no rsID) as the candidate cause of autosomal dominant LVNC. Sanger sequencing confirmed this novel variant in the proband, his father, and sister, but not in the proband's grandmother. Even within families harboring the same variant, a variable risk of adverse outcomes is common. Therefore, familial screening for patients with LVNC associated with ACTN2 variant should be performed for early detection of the LVNC phenotype associated with poor outcomes, such as dilated LVNC.

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.

Left Ventricle Non-Compaction Cardiomyopathy Admitted With Multiorgan Failure: A Case Report

Left ventricle non-compaction (LVNC) is a rare congenital cardiomyopathy characterized by thickened myocardium due to an arrest of the normal compaction of the embryonic sponge-like meshwork of myocardial fibers. 

We present a 40-year-old man with no known systemic illnesses admitted with cardiogenic shock and multiorgan failure. Echocardiogram revealed severe enlargement of all four chambers with left ventricular ejection fraction (LVEF) <10%. Cardiac magnetic resonance imaging (CMR) showed hypertrabecular left ventricular myocardium with a ratio of non-compact to compact myocardium of 2.3, diffuse myocardial thinning, and a 16-mm left ventricular thrombus. These findings were compatible with LVNC. The patient was treated with intravenous inotropic vasopressors for cardiogenic shock and enoxaparin as bridging for warfarin to a goal of INR 2.0-3.0. Due to refractory heart failure (HF) and dependency on inotropic support, the patient was placed on the waiting list for a heart transplant. Unfortunately, 27 days after admission, he presented ventricular tachycardia arrest and did not respond to aggressive advanced cardiac life support measures. 

A high index of suspicion is required for the early diagnosis, which in turn allows the physician to prevent complications of this condition. There is no specific therapy, so management is directed toward the clinical manifestations including HF, arrhythmias, and systemic embolic events. Heart transplantation is the only definitive treatment.

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.

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.

Are We Getting Closer to Risk Stratification in Left Ventricular Noncompaction Cardiomyopathy?

See Article by Shijie Li et al.

Clinical implications of sarcomere and nonsarcomere gene variants in patients with left ventricular noncompaction cardiomyopathy

Background

Robust data regarding genotype–phenotype correlations in left ventricular noncompaction cardiomyopathy (LVNC) are lacking.

Methods

About 72 cardiomyopathy‐related genes were comprehensively screened in a cohort of LVNC patients using targeted sequencing. Baseline and follow‐up data were collected. The primary endpoint was a composite of death and heart transplantation.

Results

A total of 83 unrelated adult patients were included in analyses. Following stringent classification according to the American College of Medical Genetics and Genomics (ACMG) guidelines, 36 pathogenic variants of 14 genes were detected in 32 patients. Among them, 12 patients carried at least one nonsarcomere variant (NSV). At baseline, NSV carriers had a higher frequency of atrial fibrillation, but lower left ventricular ejection fraction, than did noncarriers. During a median follow‐up of 4.2 years, NSV carriers experienced a higher rate of the primary endpoint compared with noncarriers. There was no significant difference in the rate between carriers of sarcomere variant (SV) and noncarriers, as well as between carriers of SV and NSV. The presence of NSV was associated with an increased risk of the primary endpoint independent of age, sex, and cardiac function (hazard ratio: 3.61, 95% confidence interval: 1.42–9.19, p = .002).

Conclusion

NSV may act as a genetic modifier and worsen the clinical phenotype in patients with LVNC.

A New Diagnosis of Left Ventricular Non-Compaction in a Patient Presenting with Acute Heart Failure

Left ventricular non-compaction is an overall rare cardiomyopathy; however, it is increasingly being recognized with advances in imaging technology. We present the case of a 47-year-old man with new diagnosis of heart failure and left ventricular non-compaction. We review the literature regarding diagnostic imaging criteria and management of this condition.

Quantification of the detailed cardiac left ventricular trabecular morphogenesis in the mouse embryo

During embryogenesis, a mammalian heart develops from a simple tubular shape into a complex 4-chamber organ, going through four distinct phases: early primitive tubular heart, emergence of trabeculations, trabecular remodeling and development of the compact myocardium. In this paper we propose a framework for standardized and subject-independent 3D regional myocardial complexity analysis, applied to analysis of the development of the mouse left ventricle. We propose a standardized subdivision of the myocardium into 3D overlapping regions (in our case 361) and a novel visualization of myocardial complexity, whereupon we: 1) extend the fractal dimension, commonly applied to image slices, to 3D and 2) use volume occupied by the trabeculations in each region together with their surface area, in order to quantify myocardial complexity. The latter provides an intuitive characterization of the complexity, given that compact myocardium will tend to occupy a larger volume with little surface area while high surface area with low volume will correspond to highly trabeculated areas. Using 50 mouse embryo images at 5 different gestational ages (10 subjects per gestational age), we demonstrate how the proposed representation and complexity measures describe the development of LV myocardial complexity. The mouse embryo data was acquired using high resolution episcopic microscopy. The complexity analysis per region was carried out using: 3D fractal dimension, myocardial volume, myocardial surface area and ratio between the two. The analysis of gestational ages was performed on embryos of 14.5, 15.5, 16.5, 17.5 and 18.5 embryonic days, and demonstrated that the regional complexity of the trabeculations increases longitudinally from the base to the apex, with a maximum around the middle. The overall complexity decreases with gestational age, being most complex at 14.5. Circumferentially, at ages 14.5, 15.5 and 16.5, the trabeculations show similar complexity everywhere except for the anteroseptal and inferolateral area of the wall, where it is smaller. At 17.5 days, the regions of high complexity become more localized towards the inferoseptal and anterolateral parts of the wall. At 18.5 days, the high complexity area exhibits further localization at the inferoseptal and anterior part of the wall.

Heart Failure Secondary to Left Ventricular Non-compaction Cardiomyopathy in a 26-Year-Old Male

Left ventricular non-compaction (LVNC) is a genetic anomaly where the ventricular wall is replaced by thick ventricular trabeculations with deep intertrabecular recesses held together by a thin compacted layer. We present a case of a 26-year-old male who presented with dyspnea on exertion and edema in his legs for the last one week.

Novel Genetic Triggers and Genotype-Phenotype Correlations in Patients With Left Ventricular Noncompaction

BACKGROUND

Left ventricular noncompaction (LVNC) is a genetically and phenotypically heterogeneous disease and, although increasingly recognized in clinical practice, there is a lack of widely accepted diagnostic criteria. We sought to identify novel genetic causes of LVNC and describe genotype-phenotype correlations.

METHODS AND RESULTS

A total of 190 patients from 174 families with left ventricular hypertrabeculation (LVHT) or LVNC were referred for cardiac magnetic resonance and whole-exome sequencing. A total of 425 control individuals were included to identify variants of interest (VOIs). We found an excess of 138 VOIs in 102 (59%) unrelated patients in 54 previously identified LVNC or other known cardiomyopathy genes. VOIs were found in 68 of 90 probands with LVNC and 34 of 84 probands with LVHT (76% and 40%, respectively; P<0.001). We identified 0, 1, and ≥2 VOIs in 72, 74, and 28 probands, respectively. We found increasing number of VOIs in a patient strongly correlated with several markers of disease severity, including ratio of noncompacted to compacted myocardium (P<0.001) and left ventricular ejection fraction (P=0.01). The presence of sarcomeric gene mutations was associated with increased occurrence of late gadolinium enhancement (P=0.004).

CONCLUSIONS

LVHT and LVNC likely represent a continuum of genotypic disease with differences in severity and variable phenotype explained, in part, by the number of VOIs and whether mutations are present in sarcomeric or nonsarcomeric genes. Presence of VOIs is common in patients with LVHT. Our findings expand the current clinical and genetic diagnostic approaches for patients with LVHT and LVNC.

Cardiomyopathies Due to Left Ventricular Noncompaction, Mitochondrial and Storage Diseases, and Inborn Errors of Metabolism

The normal function of the human myocardium requires the proper generation and utilization of energy and relies on a series of complex metabolic processes to achieve this normal function. When metabolic processes fail to work properly or effectively, heart muscle dysfunction can occur with or without accompanying functional abnormalities of other organ systems, particularly skeletal muscle. These metabolic derangements can result in structural, functional, and infiltrative deficiencies of the heart muscle. Mitochondrial and enzyme defects predominate as disease-related etiologies. In this review, left ventricular noncompaction cardiomyopathy, which is often caused by mutations in sarcomere and cytoskeletal proteins and is also associated with metabolic abnormalities, is discussed. In addition, cardiomyopathies resulting from mitochondrial dysfunction, metabolic abnormalities, storage diseases, and inborn errors of metabolism are described.

Autosomal Dominant Polycystic Kidney Patients May Be Predisposed to Various Cardiomyopathies

Introduction

Mutations in PKD1 and PKD2 cause autosomal dominant polycystic kidney disease (ADPKD). Experimental evidence suggests an important role of the polycystins in cardiac development and myocardial function. To determine whether ADPKD may predispose to the development of cardiomyopathy, we have evaluated the coexistence of diagnoses of ADPKD and primary cardiomyopathy in our patients.

Methods

Clinical data were retrieved from medical records for patients with a coexisting diagnosis of ADPKD and cardiomyopathies evaluated at the Mayo Clinic (1984-2015).

Results

Among the 58 of 667 patients with available echocardiography data, 39 (5.8%) had idiopathic dilated cardiomyopathy (IDCM), 17 (2.5%) had hypertrophic obstructive cardiomyopathy, and 2 (0.3%) had left ventricular noncompaction. Genetic data were available for 19, 8, and 2 cases of IDCM, hypertrophic obstructive cardiomyopathy, and left ventricular noncompaction, respectively. PKD1 mutations were detected in 42.1%, 62.5%, and 100% of IDCM, hypertrophic obstructive cardiomyopathy, and left ventricular noncompaction cases, respectively. PKD2 mutations were detected only in IDCM cases and were overrepresented (36.8%) relative to the expected frequency in ADPKD (15%). In at least 1 patient from 3 IDMC families and 1 patient from a hypertrophic obstructive cardiomyopathy family, the cardiomyopathy did not segregate with ADPKD, suggesting that the PKD mutations may be predisposing factors rather than solely responsible for the development of cardiomyopathy.

Discussion

Coexistence of ADPKD and cardiomyopathy in our tertiary referral center cohort appears to be higher than expected by chance. We suggest that PKD1 and PKD2 mutations may predispose to primary cardiomyopathies and that genetic interactions may account for the observed coexistence of ADPKD and cardiomyopathies.

Left Ventricular Noncompaction in Older Patients

BACKGROUND

Information on left ventricular noncompaction (LVNC) in older people is sparse. This study aimed to investigate the clinical profile of LVNC in an older cohort.

MATERIALS AND METHODS

Between August 2007 and September 2015, older patients (age ≥ 60 years) who were diagnosed with LVNC using cardiovascular magnetic resonance were prospectively enrolled at our hospital.

RESULTS

A total of 35 patients (male, 80%; mean age, 65 ± 5 years) were prospectively included in this study. LVNC was not detected in 18 patients (51%) at the initial echocardiographic evaluation. Of the 21 patients who received coronary imaging, 8 patients (38%) had coronary artery disease. Left ventricular (LV) dysfunction and dilation were detected in 31 patients (89%) and 30 patients (86%), respectively. Nine patients (26%) died during a follow-up period of 2.9 ± 2.3 years. Cox analysis showed that patients with syncope (hazard ratio [HR] = 20.51; 95% CI: 1.70-246.60; P = 0.02), increased LV end-diastolic diameter (HR = 1.12; 95% CI: 1.01-1.24; P = 0.03), decreased LV ejection fraction (HR = 0.87; 95% CI: 0.77-0.98; P = 0.02) and the presence of late gadolinium enhancement on cardiovascular magnetic resonance (HR = 8.9; 95% CI: 1.07-74.08; P = 0.04) had a higher risk for death.

CONCLUSIONS

The diagnosis of LVNC is easily missed at echocardiographic assessment in older patients. Coronary artery disease is a common concomitant disorder in these patients. Older patients with LVNC have a high risk for mortality. Syncope, LV dilation, systolic dysfunction and late gadolinium enhancement are related to adverse outcomes in older patients.

Left Ventricular Assist Device Insertion in a Patient With Biventricular Noncompaction Cardiomyopathy, Ebstein Anomaly, and a Left Atrial Mass: A Case Report

In this report, we present the case of a patient with biventricular noncompaction cardiomyopathy, Ebstein anomaly, and a left atrial mass who required emergent placement of a left ventricular assist device. The noncompaction cardiomyopathy complicated the left ventricular assist device implantation procedure because the thickened, trabeculated myocardium made it difficult to place the inflow cannula. We discuss our perioperative management strategy, in which transesophageal echocardiography was used, to help the surgical team identify the proper cannula placement and provide a bridge to transplantation.

Two potentially fatal surprises in the preoperative assessment of an asymptomatic young adult

Isolated left ventricular non-compaction is a rare disease classified as a primary genetic cardiomyopathy and is characterized by heart failure, systemic embolism and ventricular arrhythmias. The diagnosis is established by Doppler echocardiography. We report the case of an asymptomatic young adult, with no history of heart disease, who underwent preoperative assessment for low-risk orthopedic surgery. The electrocardiogram showed left bundle branch block, which prompted further investigation with Doppler echocardiography, cardiac computed tomography angiography and cardiac magnetic resonance imaging. A diagnosis of isolated left ventricular non-compaction and pulmonary embolism was made. Some aspects of preoperative assessment in low-risk surgical patients are discussed.

A rare form of cardiomyopathy: left ventricular non-compaction cardiomyopathy

Left ventricular non-compaction is a recently recognized, rare form of cardiomyopathy. It is based on the arrest of endomyocardial morphogenesis during embryogenesis. It was first described in 1984 by Engberding who described it as isolated ‘sinusoids’ within the LV. Right now its prevalence is estimated at 0.014 to 1.3 and 3–4% in heart failure patients. Its clinical manifestations are highly variable, ranging from no symptoms to disabling congestive heart failure, arrhythmias, and systemic thromboemboli. Doppler Echocardiogram is considered the diagnostic procedure of choice and treatment is symptomatic management of its symptoms and complications.

Inherited Structural Heart Diseases With Potential Atrial Fibrillation Occurrence

Inherited cardiac diseases inducing structural remodeling of the myocardium sometimes develop arrhythmias of various kinds. Among these rhythm disturbances, atrial fibrillation is well known to frequently worsen the prognosis of the primary disorder by increasing morbidity and mortality, especially because of a higher rate of heart failure. In this manuscript, we have reviewed the literature on the most important inherited structural cardiac diseases in whose clinical history atrial fibrillation may occur fairly often.

DAAM1 and DAAM2 are co-required for myocardial maturation and sarcomere assembly

Wnt ligands regulate heart morphogenesis but the underlying mechanisms remain unclear. Two Formin-related proteins, DAAM1 and 2, were previously found to bind the Wnt effector Disheveled. Here, since DAAM1 and 2 nucleate actin and mediate Wnt-induced cytoskeletal changes, a floxed-allele of Daam1 was used to disrupt its function specifically in the myocardium and investigate Wnt-associated pathways. Homozygous Daam1 conditional knockout (CKO) mice were viable but had misshapen hearts and poor cardiac function. The defects in Daam1 CKO mice were observed by mid-gestation and were associated with a loss of protrusions from cardiomyocytes invading the outflow tract. Further, these mice exhibited noncompaction cardiomyopathy (NCM) and deranged cardiomyocyte polarity. Interestingly, Daam1 CKO mice that were also homozygous for an insertion disrupting Daam2 (DKO) had stronger NCM, severely reduced cardiac function, disrupted sarcomere structure, and increased myocardial proliferation, suggesting that DAAM1 and DAAM2 have redundant functions. While RhoA was unaffected in the hearts of Daam1/2 DKO mice, AKT activity was lower than in controls, raising the issue of whether DAAM1/2 are only mediating Wnt signaling. Daam1-floxed mice were thus bred to Wnt5a null mice to identify genetic interactions. The hearts of Daam1 CKO mice that were also heterozygous for the null allele of Wnt5a had stronger NCM and more severe loss of cardiac function than Daam1 CKO mice, consistent with DAAM1 and Wnt5a acting in a common pathway. However, deleting Daam1 further disrupted Wnt5a homozygous-null hearts, suggesting that DAAM1 also has Wnt5a-independent roles in cardiac development.

Left ventricular non-compaction cardiomyopathy

Left ventricular non-compaction, the most recently classified form of cardiomyopathy, is characterised by abnormal trabeculations in the left ventricle, most frequently at the apex. It can be associated with left ventricular dilation or hypertrophy, systolic or diastolic dysfunction, or both, or various forms of congenital heart disease. Affected individuals are at risk of left or right ventricular failure, or both. Heart failure symptoms can be induced by exercise or be persistent at rest, but many patients are asymptomatic. Patients on chronic treatment for compensated heart failure sometimes present acutely with decompensated heart failure. Other life-threatening risks of left ventricular non-compaction are ventricular arrhythmias or complete atrioventricular block, presenting clinically as syncope, and sudden death. Genetic inheritance arises in at least 30-50% of patients, and several genes that cause left ventricular non-compaction have been identified. These genes seem generally to encode sarcomeric (contractile apparatus) or cytoskeletal proteins, although, in the case of left ventricular non-compaction with congenital heart disease, disturbance of the NOTCH signalling pathway seems part of a final common pathway for this form of the disease. Disrupted mitochondrial function and metabolic abnormalities have a causal role too. Treatments focus on improvement of cardiac efficiency and reduction of mechanical stress in patients with systolic dysfunction. Further, treatment of arrhythmia and implantation of an automatic implantable cardioverter-defibrillator for prevention of sudden death are mainstays of therapy when deemed necessary and appropriate. Patients with left ventricular non-compaction and congenital heart disease often need surgical or catheter-based interventions. Despite progress in diagnosis and treatment in the past 10 years, understanding of the disorder and outcomes need to be improved.

Asymptomatic left ventricular noncompaction--implications for athletic participation

Left ventricular noncompaction (LVNC) is a poorly understood and much debated morphological abnormality of the left ventricular myocardium. Much of what is known about this cardiomyopathy derives from large referral centers in patients presenting with significant symptoms and advanced disease. Disease progression and outcomes for adult patients with incidentally found and asymptomatic LVNC have not been established yet. As such, there are currently no evidence-based recommendations on clinical follow-up or interventions. Since LVNC's effect on athletic participation is unknown, there is insufficient evidence to support limiting athletic participation in low-risk individuals.

Heart transplant outcomes in patients with left ventricular non-compaction cardiomyopathy

BACKGROUND

Left ventricular non-compaction cardiomyopathy (LVNCC) is a rare disease that starts in utero and may progress to heart failure (HF), sometimes requiring orthotopic heart transplantation (OHT). There are limited data addressing characteristics of LVNCC patients that require OHT and their outcomes. We therefore sought to investigate the characteristics and outcomes of LVNCC patients treated with OHT.

METHODS

We queried the United Network for Organ Sharing (UNOS) database for all patients listed for OHT with LVNCC as the primary heart failure etiology between 2000 and 2013. We examined their characteristics at listing and outcomes after OHT and compared the findings with those of patients with idiopathic cardiomyopathy (IDCMP).

RESULTS

We identified 113 patients (43 adults and 70 pediatrics) with LVNCC of 45,298 patients (0.25% overall, 0.11% of adults and 1.0% of pediatrics) listed for OHT in this time period. Most were male children with mean age at listing of 16.9 years. Compared with the overall IDCMP cohort, patients with LVNCC were younger, had higher use of inotropes and extracorporeal membrane oxygenation (ECMO), and were more often listed as UNOS Status 1A with shorter waiting time. However, when adjusted for age, gender and ethnicity, these differences disappeared. During transplant listing, 8 (7.9%) died, 5 (5.0%) improved and avoided transplant, 3 (3.0%) became too sick for transplant and 78 (77.2%) underwent OHT. There was a non-significant trend toward longer cardiac allograft survival in patients with LVNCC (10.6 vs. 9.4 years; log-rank test, p = 0.068). Patients with LVNCC had similar outcomes to other IDCMP patients, except for more post-transplant infections (50.0% vs. 21.6%, p < 0.05).

CONCLUSIONS

LVNCC patients undergoing heart transplantation are mostly pediatric and predominantly bridged to transplant with inotropes or ECMO. Despite having more post-transplant infections, their survival is similar to that of other IDCMP patients.

Clinical outcomes in patients with isolated left ventricular noncompaction and heart failure

BACKGROUND

We prospectively evaluated long-term clinical outcomes of patients diagnosed with isolated left ventricular noncompaction (ILVNC) and heart failure from a sub-Saharan African population.

METHODS AND RESULTS

Patients in this single-center study were followed at a tertiary care institution. Clinical follow-up was performed with the use of protocol-driven echocardiographic screening for ventricular thrombus every 4 months. Warfarin was maintained or initiated only if thrombus was detected with the use of echocardiography. Fifty-five patients were followed for 16.7 ± 5.9 (range 12-33) months. All individuals had left ventricular (LV) ejection fraction <50% (mean 29.6 ± 11.8%). Of the 55 patients, 7 (12.7%) died, and sudden cardiac death was the cause in 5 (71.4%). There were no differences in baseline clinical, echocardiographic, or electrocardiographic characteristics between survivors and nonsurvivors. Recurrent heart failure developed in 12 patients (21.8%); 1 patient developed a ventricular arrhythmia. No thromboembolic or major bleeding complications occurred in the 16 patients on warfarin; 1 episode of thromboembolism occurred in the 39 patients not on warfarin. Mean survival probability at 33 months was 0.64.

CONCLUSIONS

Sudden cardiac death was the most common cause of death in patients with ILVNC and heart failure. Recurrent heart failure occurred in 21.8% of patients. Development of LV thrombus and cardioembolism is uncommon in this population.

Hypertrophic cardiomyopathy associated with left ventricular noncompaction cardiomyopathy and coronary fistulae: a case report. One genotype, three phenotypes?

The authors present a rare case of hypertrophic cardiomyopathy associated with left ventricular noncompaction cardiomyopathy and coronary artery-left ventricular fistulae in a 42-year-old woman presenting with non-ST-elevation myocardial infarction. Coronary angiography, transthoracic echocardiography and cardiac magnetic resonance revealed the structural abnormalities of the left ventricle and the coronary tree.

Comparison of systolic and diastolic criteria for isolated LV noncompaction in CMR

OBJECTIVES

This study used cardiac magnetic resonance (CMR) to compare standard criteria for left ventricular noncompaction (LVNC).

BACKGROUND

LVNC as a distinct cardiomyopathy is supported by a growing number of publications. Echocardiographic and CMR criteria have been established to diagnosis LVNC but have led to concerns of diagnostic accuracy.

METHODS

Trabeculation/possible LVNC by CMR was retrospectively observed in 122 consecutive cases. We compared the standard end-systolic noncompacted-to-compacted ratio (ESNCCR), end-diastolic noncompacted:compacted ratio (EDNCCR), and trabecular mass-to-total mass ratio (TMTMR) along with deaths, embolic events, congestive heart failure (CHF) readmissions, ventricular arrhythmias, myocardial thickening (MT), left ventricular ejection fraction (LVEF), 3-dimensional sphericity index (3DSi), and left ventricular end-diastolic volume index. Adjusting for age, race, sex, body surface area, diabetes mellitus, hypertension, hyperlipidemia, coronary artery disease, and CHF, logistic regression was used to compare combined events (death, CHF readmission, embolism, ventricular arrhythmia) between ESNCCR, EDNCCR, and TMTMR. Adjusting for same covariates except CHF, logistic regression was used to compare the odds of CHF for those who met criteria and those who did not. Using analysis of covariance, adjusted means for LVEF, MT, 3DSi, and left ventricular end-diastolic volume index were generated.

RESULTS

ES criteria had a higher odds ratio (8.6; 95% confidence interval [CI]: 2.5 to 33) for combined events than ED criteria (1.8; 95% CI: 0.6 to 5.8) or TMTMR criteria (3.14; 95% CI: 1.09 to 10.2). The odds ratio of CHF for those who met ESNCCR criteria was 29.4 (95% CI: 6.6 to 125), but the odds ratio of CHF for those who met EDNCCR criteria was 3.3 (95% CI: 1.1 to 9.2). After adjustment, those who met criteria for noncompaction by ESNCCR had a lower LVEF and less MT than those who did not (p = 0.01 and p = 0.003, respectively), but there was no difference between those who met criteria for EDNCCR or the TMTMR criteria and those who did not.

CONCLUSIONS

ES measures of LVNC have stronger associations with events, CHF, and systolic dysfunction than other measures.

Diagnosis of left ventricular noncompaction by computed tomography

Left ventricular noncompaction (LVNC) is a rare disorder in which the left ventricular endocardial surface is not appropriately flattened and is heavily trabeculated. Patients with this condition can be affected by stroke from emboli that originate from these recesses. We present a patient with LVNC who was originally misdiagnosed as having an idiopathic dilated cardiomyopathy. Ultimately, diagnosis of LVNC was confirmed through the use of 64-slice multidetector cardiac computed tomography (CT). There are few reports of using multidetector CT for diagnosis of LVNC, but this appears to be a viable option in confirming the diagnosis and at the same time assessing the coronary arteries. The recognition of this cardiomyopathy and its differentiation from other nonischemic cardiomyopathies have important implications for the patient and for family members, given its potential familial inheritance patterns and poor long-term prognosis.

Left ventricular thrombus and subsequent thromboembolism, comparison of anticoagulation, surgical removal, and antiplatelet agents

Left ventricular (LV) thrombus is one of the risk factors for systemic thromboembolism. The aims of this study were to compare the long-term clinical outcomes of LV thrombus using current therapeutics, anticoagulation, operative treatment, and antiplatelet agents and to identify independent predictors of systemic thromboembolism.

METHODS

We screened 86,374 patients for intracardiac thrombus in the electronic medical records and imaging databases. Records of 62 patients with LV thrombus, diagnosed between May 2003 to November 2011, were comprehensively reviewed regarding baseline characteristics, imaging data and thrombus outcomes, thromboembolic events and treatment complications by treatment group.

RESULTS

The majority (80.6%) had ischemic etiology. Systemic thromboembolism developed in 18 patients; 8 (45%) were post-treatment thromboembolisms while 10 events occurred before treatment began. No post-treatment thromboembolism occurred in the operative treatment group; in contrast, 7 post-treatment thromboembolisms occurred in anticoagulation group (17%) (Log rank p= 0.175). Independent predictors of post-treatment thromboembolism were dilated cardiomyopathy (HR 61.30, p= 0.001), previous cerebrovascular events (HR 7.06, p= 0.042), female gender (HR 7.11, p= 0.031), and echocardiographic left ventricular end-diastolic diameter (HR 1.15, p= 0.047).

CONCLUSIONS

In this study, the rate of post-treatment thromboembolism was not significantly different among the treatment groups; however, operative treatment tended towards less post-treatment thromboembolism than other treatment groups.

Rhythm disorders in isolated left ventricular noncompaction

Both supraventricular and ventricular rhythm disorders are frequently observed in patients with isolated left ventricular noncompaction (IVNC). Most importantly, these patients are prone to develop life-threatening ventricular arrhythmias, which are amongst their most frequent causes of death. Data regarding risk stratification of ventricular arrhythmias, however, are scarce due to the rareness of the disease. Indeed, even invasive electrophysiological studies may be of limited value in this regard in the majority of patients. Implantable cardioverter defibrillators (ICDs) have been demonstrated to be highly effective for the prevention of sudden arrhythmic death in IVNC and should be considered in patients who are clinically judged to be at high risk for ventricular tachyarrhythmias. These include patients with a severely reduced ejection fraction as well as those with a prior history of sustained ventricular tachycardia or fibrillation, recurrent syncope of unknown etiology, or a family history of ventricular tachyarrhythmias or sudden cardiac death. This review summarizes the electrocardiographic and electrophysiological findings in patients with IVNC and discusses possibilities for risk stratification as well as the rationale for ICD implantation for the prevention of sudden cardiac death.

Left ventricular noncompaction: a 25-year odyssey

Left ventricular noncompaction (LVNC) is a cardiomyopathy associated with sporadic or familial disease, the latter having an autosomal dominant mode of transmission. The clinical features associated with LVNC vary from asymptomatic to symptomatic patients, with the potential for heart failure, supraventricular and ventricular arrhythmias, thromboembolic events, and sudden cardiac death. Echocardiography is the diagnostic modality of choice, revealing the pathognomonic features of a thick, bilayered myocardium; prominent ventricular trabeculations; and deep intertrabecular recesses. Widespread use and advances in the technology of echocardiography and cardiac magnetic resonance imaging are increasing awareness of LVNC, and cardiac magnetic resonance imaging is improving the ability to stage the severity of the disease and potential for adverse clinical consequences. Study of LVNC through research in embryology, imaging, and genetics has allowed enormous strides in the understanding of this heterogeneous disease over the past 25 years.