Non-compaction Cardiomyopathy: Prevalence, Prognosis, Pathoetiology, Genetics, and Risk of Cardioembolism

Recommendations for the Management of Cardiomyopathy Mutation Carriers: Evidence, Doubts, and Intentions

Cardiomyopathies may be hereditary and associated with a familial predilection. Morbidity and mortality can be caused by heart failure, sudden death, or arrhythmias. Sometimes these events are the first manifestations of cardiovascular disease. Hypertrophic cardiomyopathy and arrhythmogenic cardiomyopathy are perhaps most thoroughly studied in that context. Dilated cardiomyopathy, although most frequently of secondary etiology, has a significant familial cluster. Noncompaction of the left ventricle can sometimes be seen in healthy individuals and, in other instances, is associated with severe LV dysfunction. Genetic testing is of utmost importance, since it might allow for the identification of individuals carrying mutations predisposing them to these diseases. In addition, certain variants may benefit from tailored therapeutic regimens, and thus searching for a causal mutation can impact clinical practice and is recommended for all patients with HCM or ACM. Patients with DCM and positive family history should be included as well. Regular follow-ups are advised, even in those with negative phenotypes, because these disorders are often age dependent. During pregnancy and in the case of athletes, special consideration should be made as well. We intend to summarize the most current evidence regarding their management.

Association of Myocardial Muscle Non-Compaction and Multiple Ventricular Septal Defects by Echocardiography

The aim of this study is to examine the possible high association between multiple ventricular septal defect (mVSDs) and noncompaction cardiomyopathy (NCM) as same embryological origin, and the effect of depressed ventricular function in NCM cases during the follow-up, using echocardiography. A total of 150 patients with mVSDs were diagnosed in a single center in Saudi Arabia; 40 cases with isolated or associated with minor congenital heart disease were recruited. Three specialist echocardiography consultants confirmed the NCM diagnosis separately using Jenni, Chin and Patrick criteria, and myocardial function was estimated by ejection fraction at admission and at follow-up after surgery. Stata-14 to analyze the data was used. In our cohort of 40 cases with mVSD (median age at diagnosis = 0.5 years; mean follow-up = 4.84 years), 13(33%) had criteria of non-compaction confirmed by the three specialist consultants. All were operated by surgery and 11 hybrid approach (interventional & surgery). A significant relationship between abnormal trabeculations and mVSD with or without non-compaction was observed, 34% vs 66% respectively (p < 0.03, Fisher's exact test). A repeated-measures t-test found the difference between follow-up and preoperative ejection-fractions to be statistically significant (t (39) = 2.07, p < 0.04). Further, the myocardial function in the mVSD non-compaction group normalized substantially postoperatively compared with preoperative assessment (mean difference (MD) 11.77, 95% CI: 4.40-19.14), whilst the mVSD group with normal myocardium had no significant change in the myocardium function (MD 0.74, 95% CI: -4.10-5.58). Thus, treatment outcome appears better in the mVSD non-compaction group than their peers with normal myocardium. Acknowledging the lack of genetic data, it is evident the high incidence of non-compaction in this cohort of patients with mVSD and supports our hypothesis of embryonic/genetic link, unlikely to be explained by acquired cardiomyopathy.

Left Ventricular Noncompaction as a Rare Cause of Syncope

Left ventricular noncompaction (LVNC) is a relatively rare myocardial disorder which is characterized by trabeculations and deep intertrabecular recesses within the left ventricle. LVNC is often asymptomatic but may present with heart failure, arrhythmias, or systemic thromboembolism. Uncommonly, patients with LVNC can present with syncope. In this article, we report one such presentation of this rare medical condition.

The pivotal role of cardiovascular imaging in the identification and risk stratification of non-compaction cardiomyopathy patients

Non-compaction cardiomyopathy (NCM) is a heterogeneous myocardial disease that can finally lead to heart failure, arrhythmias, and/or embolic events. Therefore, early diagnosis and treatment is of paramount importance. Furthermore, genetic assessment and counseling are crucial for individual risk assessment and family planning. Echocardiography is the first-line imaging modality. However, it is hampered by interobserver variability, depends among others on the quality of the acoustic window, cannot assess reliably the right ventricle and the apex, and cannot provide tissue characterization. Cardiovascular magnetic resonance (CMR) provides a 3D approach allowing imaging of the entire heart, including both left and right ventricle, with low operator variability or limitations due to patient's body structure. Furthermore, tissue characterization, using late gadolinium enhancement (LGE), allows the detection of fibrotic areas possibly representing the substrate for potentially lethal arrhythmias, predicts the severity of LV systolic dysfunction, and differentiates apical thrombus from fibrosis. Conversely, besides being associated with high costs, CMR has long acquisition/processing times, lack of expertise among cardiologists/radiologists, and limited availability. Additionally, in cases of respiratory and/or cardiac motion artifacts or arrhythmias, the cine images may be blurred. However, CMR cannot be applied to patients with not CMR-compatible implanted devices and LGE may be not available in patients with severely reduced GFR. Nevertheless, native T1 mapping can provide detailed tissue characterization in such cases. This tremendous potential of CMR makes this modality the ideal tool for better risk stratification of NCM patient, based not only on functional but also on tissue characterization information.

Left Ventricular Non-compaction Cardiomyopathy: Delayed Diagnosis and Deleterious Outcomes

Cardiomyopathy and associated heart failure have uncommon etiologies, which when diagnosed reduce patients’ morbidity and mortality. One such entity is left ventricular non-compaction cardiomyopathy (LVNC). Still, a relatively uncommon entity, the manifestation of LVNC may range from asymptomatic to left ventricular dysfunction, congestive heart failure, ventricular tachycardia, sudden cardiac death, and thromboembolic complications. If not pursued as a possible etiology of non-ischemic cardiomyopathy, patients may have significantly increased morbidity prior to eventual diagnosis. Patients are often predisposed to ventricular arrhythmias requiring implantable cardiac defibrillator placement. Additionally, due to the depth of trabeculations, there is an associated thromboembolic risk requiring therapeutic anticoagulation. We present the case of a 41-year-old man with progressively worsening heart failure due to undiagnosed LVNC and the associated deleterious manifestations and outcomes.

High Prevalence of Left Ventricular Non-Compaction and Its Effect on Chemotherapy-Related Cardiac Dysfunction in Patients With Hematological Diseases

BACKGROUND

Recent progress in chemotherapy has prolonged the survival of patients with hematological diseases, but has also increased the number of patients with chemotherapy-related cardiac dysfunction (CTRCD). However, the causes of individual variations and risk factors for CTRCD have yet to be fully elucidated.Methods and Results:Consecutive echocardiograms of 371 patients were retrospectively evaluated for the presence of left ventricular (LV) non-compaction (LVNC). Individual LV ejection fraction (LVEF) outcome estimates were made using bivariate linear regression with log-transformed duration Akaike information criterion (AIC) model fitting. The prevalence of LVNC was 6-fold higher in patients with hematological diseases than in those with non-hematological diseases (12% vs. 2%; risk ratio 6.1; 95% confidence interval [CI] 2.0, 18.2). Among patients with hematological diseases, the ratio of myeloid diseases was significantly higher in the group with LVNC (P=0.031). Deterioration of LVEF was more severe in patients with than without LVNC (-14.4 percentage points/year [95% CI -21.0, -7.9] vs. -4.6 percentage points/year [95% CI -6.8, -2.4], respectively), even after multivariate adjustment for baseline LVEF, background disease distributions, cumulative anthracycline dose, and other baseline factors.

CONCLUSIONS

LVNC is relatively prevalent in patients with hematological diseases (particularly myeloid diseases) and can be one of the major risk factors for CTRCD. Detailed cardiac evaluations including LVNC are recommended for patients undergoing chemotherapy.

Biventricular imaging markers to predict outcomes in non-compaction cardiomyopathy: a machine learning study

Aims

Left ventricular non‐compaction cardiomyopathy (LVNC) is a genetic heart disease, with heart failure, arrhythmias, and embolic events as main clinical manifestations. The goal of this study was to analyse a large set of echocardiographic (echo) and cardiac magnetic resonance imaging (CMRI) parameters using machine learning (ML) techniques to find imaging predictors of clinical outcomes in a long‐term follow‐up of LVNC patients.

Methods and results

Patients with echo and/or CMRI criteria of LVNC, followed from January 2011 to December 2017 in the heart failure section of a tertiary referral cardiologic hospital, were enrolled in a retrospective study. Two‐dimensional colour Doppler echocardiography and subsequent CMRI were carried out. Twenty‐four hour Holter monitoring was also performed in all patients. Death, cardiac transplantation, heart failure hospitalization, aborted sudden cardiac death, complex ventricular arrhythmias (sustained and non‐sustained ventricular tachycardia), and embolisms (i.e. stroke, pulmonary thromboembolism and/or peripheral arterial embolism) were registered and were referred to as major adverse cardiovascular events (MACEs) in this study. Recruited for the study were 108 LVNC patients, aged 38.3 ± 15.5 years, 48.1% men, diagnosed by echo and CMRI criteria. They were followed for 5.8 ± 3.9 years, and MACEs were registered. CMRI and echo parameters were analysed via a supervised ML methodology. Forty‐seven (43.5%) patients had at least one MACE. The best performance of imaging variables was achieved by combining four parameters: left ventricular (LV) ejection fraction (by CMRI), right ventricular (RV) end‐systolic volume (by CMRI), RV systolic dysfunction (by echo), and RV lower diameter (by CMRI) with accuracy, sensitivity, and specificity rates of 75.5%, 77%, 75%, respectively.

Conclusions

Our findings show the importance of biventricular assessment to detect the severity of this cardiomyopathy and to plan for early clinical intervention. In addition, this study shows that even patients with normal LV function and negative late gadolinium enhancement had MACE. ML is a promising tool for analysing a large set of parameters to stratify and predict prognosis in LVNC patients.

The Role of Antithrombotic Therapy in Heart Failure

Heart failure is a major contributor to global morbidity and mortality burden affecting approximately 1-2% of adults in developed countries, mounting to over 10% in individuals aged >70 years old. Heart failure is characterized by a prothrombotic state and increased rates of stroke and thromboembolism have been reported in heart failure patients compared with the general population. However, the impact of antithrombotic therapy on heart failure remains controversial. Administration of antiplatelet or anticoagulant therapy is the obvious (and well-established) choice in heart failure patients with cardiovascular comorbidity that necessitates their use, such as coronary artery disease or atrial fibrillation. In contrast, antithrombotic therapy has not demonstrated any clear benefit when administered for heart failure per se, i.e. with heart failure being the sole indication. Randomized studies have reported decreased stroke rates with warfarin use in patients with heart failure with reduced left ventricular ejection fraction, but at the expense of excessive bleeding. Non-vitamin K oral anticoagulants have shown a better safety profile in heart failure patients with atrial fibrillation compared with warfarin, however, current evidence about their role in heart failure with sinus rhythm is inconclusive and further research is needed. In the present review, we discuss the role of antithrombotic therapy in heart failure (beyond coronary artery disease), aiming to summarize evidence regarding the thrombotic risk and the role of antiplatelet and anticoagulant agents in patients with heart failure.

Left ventricular non-compaction in a patient with ankylosing

A 58 years old male with a long-standing history of HLA-B27 positive ankylosing spondylitis presented with increasing fatigue and dyspnea on exertion. He had left ventricular dysfunction and enlargement, flail right coronary leaflet of aortic valve with severe eccentric aortic insufficiency along with left ventricular non-compaction in echocardiography. The most common cardiac manifestations of ankylosing spondylitis are aortic insufficiency and conduction disturbances. Involvement of myocardium, in the form of dilated cardiomyopathy and restrictive cardiomyopathy, has also been reported. This case presents a very rare association of ankylosing spondylitis with non-compaction cardiomyopathy.

Combination of Whole Genome Sequencing, Linkage, and Functional Studies Implicates a Missense Mutation in Titin as a Cause of Autosomal Dominant Cardiomyopathy With Features of Left Ventricular Noncompaction

Supplemental Digital Content is available in the text.

Background—

High throughput next-generation sequencing techniques have made whole genome sequencing accessible in clinical practice; however, the abundance of variation in the human genomes makes the identification of a disease-causing mutation on a background of benign rare variants challenging.

Methods and Results—

Here we combine whole genome sequencing with linkage analysis in a 3-generation family affected by cardiomyopathy with features of autosomal dominant left ventricular noncompaction cardiomyopathy. A missense mutation in the giant protein titin is the only plausible disease-causing variant that segregates with disease among the 7 surviving affected individuals, with interrogation of the entire genome excluding other potential causes. This A178D missense mutation, affecting a conserved residue in the second immunoglobulin-like domain of titin, was introduced in a bacterially expressed recombinant protein fragment and biophysically characterized in comparison to its wild-type counterpart. Multiple experiments, including size exclusion chromatography, small-angle x ray scattering, and circular dichroism spectroscopy suggest partial unfolding and domain destabilization in the presence of the mutation. Moreover, binding experiments in mammalian cells show that the mutation markedly impairs binding to the titin ligand telethonin.

Conclusions—

Here we present genetic and functional evidence implicating the novel A178D missense mutation in titin as the cause of a highly penetrant familial cardiomyopathy with features of left ventricular noncompaction. This expands the spectrum of titin’s roles in cardiomyopathies. It furthermore highlights that rare titin missense variants, currently often ignored or left uninterpreted, should be considered to be relevant for cardiomyopathies and can be identified by the approach presented here.

Non-compaction cardiomyopathy in an asymptomatic athlete

Prevention of sudden cardiac death in athletes requires the screening and recognition of pathologies that often remain clinically silent for years until provoked by a physiologic stressor. This can result in the manifestation of disease and even death. Left ventricular non-compaction cardiomyopathy (LVNC), newly classified as a distinct entity arising in the adult population, is a cardiomyopathy that at initial presentation can manifest as a wide spectrum of symptoms from asymptomatic to ventricular arrhythmias, systemic embolism and even sudden cardiac death. We present the case of an asymptomatic athlete found to have LVNC and discuss the implications this finding may have on sports participation.

Left ventricular noncompaction cardiomyopathy in end-stage heart failure patients undergoing orthotopic heart transplantation

BACKGROUND

Previous studies reported that left ventricular noncompaction (LVNC) is a cardiomyopathy, familial or sporadic, arising from arrest of the normal process of trabecular remodeling during embryonic development. The diagnosis is usually made by echocardiography, but to date, there has been little research on the occurrence and clinicopathological features of LVNC in the explanted hearts of orthotopic heart transplant (OHT) recipients.

DESIGN

The clinical, echocardiographic, and pathologic findings were reviewed for evidence of LVNC, diagnosed by echocardiographic criteria, in 105 patients with end-stage heart failure (HF) undergoing OHT. Analyses of multiple sections of the explanted hearts were carried out. The hearts were evaluated for grades (0, negative; 1, mild/occasional foci; 2, moderate/multiple foci; 3, severe/extensive, diffuse) of fibrosis, reactive and replacement, hypertrophy, myocytolysis in left ventricle, right ventricle, interventricular septum, and atria. Absolute measurements of noncompacted and compacted portions of the left ventricle wall and noncompacted/compacted ratios were calculated.

RESULTS

Isolated LVNC was observed in 0 of 54 ischemic cardiomyopathy and in 4 of 51 (7.8%) nonischemic cardiomyopathy patients - 2 men and 2 women, with a mean age±SEM of 34.2±6.9years. The echocardiogram disclosed marked left ventricular dilatation, prominent trabeculations, and left ventricle ejection fraction <20%. Mural thrombi were seen in 3 of 4 (75%) patients. The heart weight mean±SEM was 468±55.3 g (range, 340-600g); noncompacted myocardium was 22±5.8mm, compacted myocardium was 13.2±3.5mm, and noncompacted/compacted ratio was 1.7/1±0.2. The total scores of hypetrophy, myocytolysis, and fibrosis were as follows: left ventricle, 7.7±0.2; right ventricle, 6.2±0.5; interventricular septum, 6.7±0.2; and atria, 7.5±0.3.

CONCLUSIONS

LVNC is an unusual form of nonischemic cardiomyopathy in patients suffering from end-stage HF undergoing OHT. The variability in the noncompacted/compacted ratio and discordance between the echocardiographic and pathological findings points to the need for further clarification of diagnostic imaging and diagnostic criteria for LVNC. Further studies in larger series, correlating the anatomoclinical and genetic variables, also would improve our understanding of LVNC as a cause of advanced HF leading to OHT.

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.

Myocardial deformation pattern in left ventricular non-compaction: Comparison with dilated cardiomyopathy

INTRODUCTION

Left ventricular (LV) systolic dysfunction is the most frequent initial presentation of patient with LV noncompaction (NC). Our objectives were to evaluate myocardial contraction properties in patients with LVNC and the relationship of non-compacted segments with the degree of global and regional systolic deformation.

METHODS

We included 50 LVNC with an echocardiography and speckle imaging calculation of peak longitudinal strain (PLS). Each of the 16 LV myocardial segments was defined as NC (ratio NC/compacted layer > 2), borderline (NC/C 0-2) and compacted (NC/C = 0). Basal, median and apical strain values were calculated as the average of segmental strain values. For comparison a group of 50 patients with dilated cardiomyopathy (DCM) underwent the same measurements.

RESULTS

There was no statistical difference between the 2 groups for any conventional LV systolic parameters. A characteristic deformation pattern was observed in LVNC with higher strain values in the LV apical segments (- 12.8 ± 5.9 vs - 10.7 ± 5.7) and an apical-basal ratio (1.52 ± 0.73 vs 1.12 ± 0.42; p < 0.001). There was no correlation between LV function and the degree of NC. Among 726 segments, compacta thickness was thinner in NC vs C segments (6.4 ± 1.4 vs 7.7 ± 1.8 mm; p < 0.05). There was no difference in WMS but regional strain values were significantly higher in NC compared to C segments (- 13.1 ± 6.1 vs - 10.2 ± 6.3; p < 0.05).

CONCLUSIONS

Compared to DCM, LVNC presented with relatively preserved apical deformation as compared to basal segments. Lower regional deformation values in compacted segments confirm the concept that LVNC is a phenotypic marker of an underlying diffuse cardiomyopathy involving both C and NC myocardium.