Electrophysiological phenotyping of left ventricular noncompaction cardiomyopathy in pediatric populations: A systematic review.

Left ventricular noncompaction cardiomyopathy (LVNC) is a structural heart defect that has been associated with generation of arrhythmias in the population and is a cause of sudden cardiac death with severe systolic dysfunction and fatal arrhythmias. LVNC has gained increasing acknowledgment with increased prevalence. We conducted a systematic review of reported electrocardiogram (ECG) results for pediatric LVNC patients. EMBASE database query was performed, yielding 4531 articles related to LVNC between 1990 and December 2023. Patient age ranged from prenatal to 18 years of age. Qualitative analyses were performed to characterize individual arrhythmias, and summative interpretation of ECG evaluations was gathered for the entire cohort. Systematic review of 57 LVNC cases and ECG presentation revealed many waveform consistencies, including abnormal left ventricular, atrioventricular node, and interventricular septal patterns, and specifically a high incidence of Mobitz type II and Wolff-Parkinson-White waveforms. This review of ECG analysis reinforces the clinical and etiologic significance of pediatric LVNC. While LVNC in pediatric populations may not always present as acute clinical cases, further investigation into the electrophysiology of the disease supports the need for further evaluation and risk stratification for patients with suspected LVNC and/or ventricular arrhythmia.

Thinning of compact layer and systolic dysfunction in isolated left ventricular non-compaction: A cardiac magnetic resonance study.

BACKGROUND: The Petersen' index reflects an excess of myocardial trabeculation which is not a specific morpho-functional feature of left ventricular non-compaction (LVNC) cardiomyopathy, but a "phenotypic trait" even observed in association with other myocardial diseases and over-loading conditions. The present study was designed to evaluate the relation between a critical thinning of compact layer and the development of systolic dysfunction and LVNC cardiomyopathy. METHODS: We compared CMR morpho-functional features and measurements of LV wall thickness using a 17 segment model of a cohort of patients fulfilling the Petersen criterion for LVNC with LV systolic dysfunction versus those of a cohort of age- and sex-matched controls with LVNC and preserved LV systolic function. All the study patients had an "isolated" LVNC defined as positive Petersen criterion in the absence of other diseases such as hypertrophic and dilated cardiomyopathy, valvular heart disease, or congenital heart disease and over-loading conditions. RESULTS: he study population included 33 patients with "isolated" LVNC: 11 consecutive index patients with a reduced LV ejection fraction (LVNCrEF) and 22 controls with a preserved LVEF (LVNCpEF). The compact myocardial layer was thinner in patients with LVNCrEF than in those with LVNCpEF patients, both in mid-ventricular and apical LV segments. On linear regression analysis, there was a linear correlation between median thickness of mid-ventricular free wall segments and left ventricular ejection fraction (r = 0.51, p = 0.005). On the ROC curves analysis, ≥2 segments with a compact myocardial layer <5 mm in the free wall mid-ventricular segments showed the best accuracy for reduced LVEF (100% sensitivity and 60% specificity; AUC 0.81, p < 0.01). The negative predictive value for LV systolic dysfunction of <2 free wall mid ventricular segments <5 mm was 100%. On quantitative analysis, the mass of papillary muscles was lower in patients with LVNCrEF [1.2 (0.8-1.4) versus 1.6 (1.1-1.8) g/mq; p = 0.08]. CONCLUSIONS: A thinned compact layer of mid-ventricular segments of the LV free wall was associated with a reduced systolic function and "isolated" LVNC cardiomyopathy.

A novel mutation in the TTN gene resulted in left ventricular noncompaction: a case report and literature review.

BACKGROUND: Left ventricular noncompaction (LVNC) is a specific type of cardiomyopathy characterized by coarse trabeculae and interspersed trabecular crypts within the ventricles. Clinical presentation varies widely and may be nonsignificant or may present with progressive heart failure, malignant arrhythmias, and multiorgan embolism. The mode of inheritance is highly heterogeneous but is most commonly autosomal dominant. The TTN gene encodes titin, which is not only an elastic component of muscle contraction but also mediates multiple signalling pathways in striated muscle cells. In recent years, mutations in the TTN gene have been found to be associated with LVNC, but the exact pathogenesis is still not fully clarified. CASE PRESENTATION: In this article, we report a case of an adult LVNC patient with a TTN gene variant, c.87857G > A (p. Trp29286*), that has not been reported previously. This 43-year-old adult male was hospitalized repeatedly for heart failure. Echocardiography showed reduced myocardial contractility, dilated left ventricle with many prominent trabeculae, and a loose texture of the left ventricular layer of myocardium with crypt-like changes. During the out-of-hospital follow-up, the patient had no significant signs or symptoms of discomfort. CONCLUSION: This case report enriches the mutational spectrum of the TTN gene in LVNC and provides a basis for genetic counselling and treatment of this patient. Clinicians should improve their understanding of LVNC, focusing on exploring its pathogenesis and genetic characteristics to provide new directions for future diagnosis and treatment.

Excessive Trabeculation of the Left Ventricle: JACC: Cardiovascular Imaging Expert Panel Paper.

Excessive trabeculation, often referred to as "noncompacted" myocardium, has been described at all ages, from the fetus to the adult. Current evidence for myocardial development, however, does not support the formation of compact myocardium from noncompacted myocardium, nor the arrest of this process to result in so-called noncompaction. Excessive trabeculation is frequently observed by imaging studies in healthy individuals, as well as in association with pregnancy, athletic activity, and with cardiac diseases of inherited, acquired, developmental, or congenital origins. Adults with incidentally noted excessive trabeculation frequently require no further follow-up based on trabecular pattern alone. Patients with cardiomyopathy and excessive trabeculation are managed by cardiovascular symptoms rather than the trabecular pattern. To date, the prognostic role of excessive trabeculation in adults has not been shown to be independent of other myocardial disease. In neonates and children with excessive trabeculation and normal or abnormal function, clinical caution seems warranted because of the reported association with genetic and neuromuscular disorders. This report summarizes the evidence concerning the etiology, pathophysiology, and clinical relevance of excessive trabeculation. Gaps in current knowledge of the clinical relevance of excessive trabeculation are indicated, with priorities suggested for future research and improved diagnosis in adults and children.

The use of 2-D speckle tracking echocardiography in assessing adolescent athletes with left ventricular hypertrabeculation meeting the criteria for left ventricular non-compaction cardiomyopathy.

BACKGROUND: Current echocardiographic criteria cannot accurately differentiate exercise induced left ventricular (LV) hypertrabeculation in athletes from LV non-compaction cardiomyopathy (LVNC). This study aims to evaluate the role of speckle tracking echocardiography (STE) in characterising LV myocardial mechanics in healthy adolescent athletes with and without LVNC echocardiographic criteria. METHODS: Adolescent athletes evaluated at three sports academies between 2014 and 2019 were considered for this observational study. Those meeting the Jenni criteria for LVNC (end-systolic non-compacted/compacted myocardium ratio > 2 in any short axis segment) were considered LVNC+ and the rest LVNC-. Peak systolic LV longitudinal strain (Sl), circumferential strain (Sc), rotation (Rot), corresponding strain rates (SRl/c) and segmental values were calculated and compared using a non-inferiority approach. RESULTS: A total of 417 participants were included, mean age 14.5 ± 1.7 years, of which 6.5% were LVNC+ (n = 27). None of the athletes showed any additional LVNC clinical criteria. All average Sl, SRl Sc, SRc and Rot values were no worse in the LVNC+ group compared to LVNC- (p values range 0.0003-0.06), apart from apical SRc (p = 0.2). All 54 segmental measurements (Sl/Sc SRl/SRc and Rot) had numerically comparable means in both LVNC+ and LVNC-, of which 69% were also statistically non-inferior. CONCLUSIONS: Among healthy adolescent athletes, 6.5% met the echocardiographic criteria for LVNC, but showed normal LV STE parameters, in contrast to available data on paediatric LVNC describing abnormal myocardial function. STE could better characterise the myocardial mechanics of athletes with LV hypertrabeculation, thus allowing the transition from structural to functional LVNC diagnosis, especially in suspected physiological remodelling.

Informe de caso de miocardiopatía no compactada en una mujer de 34 años / Case report of left ventricular noncompaction cardiomyopathy in a 34-year-old woman

Introducción: la miocardiopatía no compactada (MCNC) es una miocardiopatía no clasificada por la Organización Mundial de la Salud. Se describe como una enfermedad congénita muy rara, donde se observan trabeculaciones endomiocárdicas que aumentan en número y prominencia. Esta miocardiopatía conlleva un alto riesgo de arritmias malignas, fenómeno tromboembólico y disfunción ventricular izquierda. Objetivo: reportar el caso de una mujer de 34 años, diagnosticada previamente con obesidad mórbida, que acudió a consulta externa para una evaluación cardiovascular prequirúrgica. El electrocardiograma mostró el ventrículo izquierdo (VI) ligeramente dilatado y llamativa trabeculación del mismo. Resultados: se confirma el diagnóstico de MCNC a través de una imagen de resonancia magnética. Se autoriza su cirugía y se recomiendan cambios en su estilo de vida y cambio de medicación para riesgos de fallo cardíaco. En el último ecocardiograma, los diámetros del VI muestran mejoría con respecto al primero. Conclusiones: la presencia de trabeculaciones en el VI debe considerarse un dato clínico de sospecha de MCNC. Se deben realizar más investigaciones sobre las causas de esta miocardiopatía no clasificada para desarrollar mejores formas terapéuticas, sin embargo, ha sido probada la eficacia de los bloqueadores de los receptores de la angiotensina II en el manejo farmacoterapéutico de esta condición

Introduction: Left ventricular non-compaction cardiomyopathy (LVNC) is a cardiomyopathy not classified by the World Health Organization. It is described as a very rare congenital disease where endomyocardial trabeculations that increase in number and prominence are observed. This cardiomyopathy carries a high risk of malignant arrhythmias, thromboembolic events and left ventricular dysfunction. Objective: To report the case of a 34-year-old woman, previously diagnosed with morbid obesity, who came to the outpatient clinic for a preoperative cardiovascular evaluation. The electrocardiogram showed a slightly dilated left ventricle (LV) and striking trabeculation. Results: The diagnosis of LVNC was confirmed by magnetic resonance imaging. Surgery was authorized and lifestyle changes and change of medication for heart failure risks were recommended. On the last echocardiogram, LV diameters show improvement from the first. Conclusions: The presence of trabeculations in the LV should be considered as clinical data of suspected LVNC. Further investigations on the causes of this unclassified cardiomyopathy should be performed to develop better therapeutic ways, however, the efficacy of angiotensin II receptor blockers in the pharmacotherapeutic management of this condition has been proven

MR -specific characteristics of left ventricular noncompaction and dilated cardiomyopathy.

BACKGROUND: The differentiation of dilated cardiomyopathy (DCM) and left ventricular noncompaction (LVNC) is a recurring issue during cardiac imaging processes; thus, we aimed to compare the left ventricular (LV) cardiac MRI characteristics of these patients. METHODS: Thirty-one nonischemic DCM patients, 42 LVNC patients with reduced ejection fraction and 42 healthy controls were included in this retrospective study. LV volumetric, functional and myocardial mass parameters were measured with a threshold-based technique, while global and segmental strain values and rotational patterns were analyzed with feature-tracking strain analysis. RESULTS: Of the LV volumetric and myocardial mass parameters, only the trabeculated and papillary muscle mass (TPMi) values differed significantly between the patient groups and were higher in the LVNC group (DCM vs LVNC: 43.2 ± 8.9 vs 51.6 ± 13.6 g/m2, p < 0.002). The global longitudinal and circumferential strains were similar between the patient groups and significantly worse than those of the controls. In comparing the segmental strains between the patient groups, only the circumferential apical strain was significantly lower in the LVNC group (DCM vs LVNC: -30.5 ± 13.5 vs -24.5 ± 12.0%, p < 0.05). There was no difference in the rotational pattern between the patient groups, and both healthy and patient populations showed heterogeneous rotational patterns. CONCLUSIONS: Despite the similarities between DCM and LVNC in volumetric, global strain parameters, and rotational patterns, we found some differences between the patient groups, as the TPMi was higher and the apical circumferential strains were significantly lower in LVNC. These minor alterations might be due to the morphological characteristics of LVNC with a trabeculated apical region.

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.

A Case of Severe Left-Ventricular Noncompaction Associated with Splicing Altering Variant in the FHOD3 Gene.

Left ventricular noncompaction (LVNC) is a highly heterogeneous primary disorder of the myocardium. Its clinical features and genetic spectrum strongly overlap with other types of primary cardiomyopathies, in particular, hypertrophic cardiomyopathy. Study and the accumulation of genotype-phenotype correlations are the way to improve the precision of our diagnostics. We present a familial case of LVNC with arrhythmic and thrombotic complications, myocardial fibrosis and heart failure, cosegregating with the splicing variant in the FHOD3 gene. This is the first description of FHOD3-dependent LVNC to our knowledge. We also revise the assumed mechanism of pathogenesis in the case of FHOD3 splicing alterations.

Right ventricular involvement in left ventricular non-compaction cardiomyopathy.

BACKGROUND: Left ventricular non-compaction cardiomyopathy (LVNC) features extensive trabeculations. Involvement of the right ventricle (RV) has been reported; however, distinction from normal RV trabeculation is difficult. This study aimed at assessing RV morphology and function in LVNC by cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE). METHODS: Dimensional and functional parameters were assessed according to guidelines. Novel CMR parameters were RV end-diastolic (ED) trabeculated area, RV ED trabeculated volume, and RV ED non-compacted to compacted (NC/N) ratio in short axis (SAX) as well as in four-chamber view (4CH). RESULTS: Twenty patients with LVNC and 20 controls were included. RV size and function were comparable in LVNC and controls and exhibited a good correlation between TTE and CMR. Although RV trabeculated area, RV trabeculated volume, and RV ED NC/C ratio in SAX as well as in 4CH were larger in LVNC, there was a major overlap with values in controls. RV ED NC/C ratio in SAX correlated with LV ED NC/C ratio (not in 4CH). Quantitative assessment of RV non-compaction was not feasible in TTE. CONCLUSIONS: Right ventricle size and function in LVNC can be measured by CMR and TTE, while RV trabeculation can only be quantified by CMR. RV myocardium displays more trabeculations in LVNC; however, overlap with normal individuals is extensive, not allowing separation of patients with LVNC from controls.

Left ventricular characteristics of noncompaction phenotype patients with good ejection fraction measured with cardiac magnetic resonance.

OBJECTIVE: We describe left ventricular (LV) volumes, myocardial and trabeculated muscle mass and strains with Cardiac magnetic resonance of a large cohort (n=81) who fulfilled the morphologic criteria of left ventricular noncompaction (LVNC) and had good ejection fraction (EF >55%) and compare them with healthy controls (n=81). Male and female patients were compared to matched controls and to each other. We also investigated the LV trabeculated muscle mass cutoff in male and female patients with LVNC. METHODS: 81 participants with LVNC and 81 healthy controls were included. Male and female patients were compared to matched controls and to each other. We also investigated the left ventricular trabeculated muscle mass cut-off in male and female LVNC patients. RESULTS: The LV parameters of the LVNC population were normal, but they had significantly higher volumes, myocardial and trabeculated muscle mass, and a significantly smaller EF than the controls. Similar differences were observed after stratifying by sex. The optimal LV trabeculated muscle mass cutoffs were 25.8 g/m2 in men (area under the curve: 0.81) and 19.0 g/m2 in women (area under the curve: 0.87). The patients had normal global strains but a significantly worse global circumferential strain (patients vs controls: -29.9±4.9 vs. -35.8±4.7%, p<0.05) and significantly higher circumferential mechanical dispersion than the controls (patients vs. controls: 7.6±4.2 vs. 6.1±2.8%; p<0.05). No disease-related strain differences were noted between men and women. CONCLUSION: The LV functional and strain characteristics of the LVNC cohort differed significantly from those of healthy participants; this might be caused by increased LV trabeculation, and its clinical relevance might be questionable. The LV trabeculated muscle mass was very different between men and women; thus, the use of sex-specific morphologic diagnostic criteria should be considered.

Left ventricular noncompaction in pediatric population: could cardiovascular magnetic resonance derived fractal analysis aid diagnosis?

BACKGROUND: Cardiovascular magnetic resonance (CMR) derived fractal analysis of the left ventricle (LV) has been shown in adults to be a useful quantitative measure of trabeculation with high reproducibility and accuracy for the diagnosis of LV non-compaction (LVNC). The aim of this study was to investigate the utility and feasibility of fractal analysis in children. METHODS: Eighty-four subjects underwent CMR: (1) 28 patients with LVNC (as defined by the Petersen criteria with NC/C ratio [Formula: see text] 2.3); (2) 28 patients referred by clinicians for assessment of hyper-trabeculation and found not to qualify as LVNC (NC/C [Formula: see text] 1.8 and < 2.3); (3) 28 controls. The fractal scores for each group were presented as global and maximal fractal dimension as well as for 3 segments of the LV: basal, mid, and apical. Statistical comparison of the fractal scores between the 3 groups was performed. RESULTS: Global fractal dimension (FD) was higher in the LVNC group than in the hyper-trabeculated group: 1.345 (SEM 0.053) vs 1.252 (SEM 0.034), p < 0.001 and higher in hyper-trabeculated group than in controls: 1.252 (SEM 0.034) vs 1.158 (SEM 0.038), p < 0.001. The highest maximum FD was in the apical portion of the LV in the LVNC group, (1.467; SEM 0.035) whereas it was in the mid ventricle in the hyper-trabeculated (1.327; SEM 0.025) and healthy groups (1.251; SEM 0.042). Fractal analysis showed lower intra- and interobserver variability than the Petersen and Jacquier methods. CONCLUSIONS: It is technically feasible to perform fractal analysis in children using CMR and that it is quick, accurate and reproducible. Fractal scoring accurately distinguishes between LVNC, hyper-trabeculation and healthy controls as defined by the Petersen criteria.

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.