A machine learning framework for the evaluation of myocardial rotation in patients with noncompaction cardiomyopathy

Aims Noncompaction cardiomyopathy (NCC) is considered a genetic cardiomyopathy with unknown pathophysiological mechanisms. We propose to evaluate echocardiographic predictors for rigid body rotation (RBR) in NCC using a machine learning (ML) based model. Methods and results Forty-nine outpatients with NCC diagnosis by echocardiography and magnetic resonance imaging (21 men, 42.8±14.8 years) were included. A comprehensive echocardiogram was performed. The layer-specific strain was analyzed from the apical two-, three, four-chamber views, short axis, and focused right ventricle views using 2D echocardiography (2DE) software. RBR was present in 44.9% of patients, and this group presented increased LV mass indexed (118±43.4 vs. 94.1±27.1g/m2, P = 0.034), LV end-diastolic and end-systolic volumes (P< 0.001), E/e’ (12.2±8.68 vs. 7.69±3.13, P = 0.034), and decreased LV ejection fraction (40.7±8.71 vs. 58.9±8.76%, P < 0.001) when compared to patients without RBR. Also, patients with RBR presented a significant decrease of global longitudinal, radial, and circumferential strain. When ML model based on a random forest algorithm and a neural network model was applied, it found that twist, NC/C, torsion, LV ejection fraction, and diastolic dysfunction are the strongest predictors to RBR with accuracy, sensitivity, specificity, area under the curve of 0.93, 0.99, 0.80, and 0.88, respectively. Conclusion In this study, a random forest algorithm was capable of selecting the best echocardiographic predictors to RBR pattern in NCC patients, which was consistent with worse systolic, diastolic, and myocardium deformation indices. Prospective studies are warranted to evaluate the role of this tool for NCC risk stratification.

Left Ventricular Noncompaction Cardiomyopathy: From Clinical Features to Animal Modeling

Cardiomyopathy or disease of the heart muscle involves abnormal enlargement and a thickened, stiff, or spongy-like appearance of the myocardium. As a result, the function of the myocardium is weakened and does not sufficiently pump blood throughout the body nor maintain a normal pumping rhythm, leading to heart failure. The main types of cardiomyopathies include dilated hypertrophic, restrictive, arrhythmogenic, and noncompaction cardiomyopathy. Abnormal trabeculations of the myocardium in the left ventricle are classified as left ventricular noncompaction cardiomyopathy (LVNC). Myocardial noncompaction most frequently is observed at the apex of the left ventricle and can be associated with chamber dilation or muscle hypertrophy, systolic or diastolic dysfunction, or both, or various forms of congenital heart disease. Animal models are incredibly important for uncovering the etiology and pathogenesis involved in this disease. This chapter will describe the clinical and pathological features of LVNC in humans and present the animal models that have been used for the study of the genetic basis and pathogenesis of this disease.

Reduced Systolic Function and Not Genetic Variants Determine Outcome in Pediatric and Adult Left Ventricular Noncompaction Cardiomyopathy

Background: Left ventricular noncompaction cardiomyopathy (LVNC CMP) is a genetic cardiomyopathy. Genotype-phenotype correlation and clinical outcome of genetic variants in pediatric and adult LVNC CMP patients are still unclear.Methods: The retrospective multicenter study was conducted in unrelated index patients with LVNC CMP, diagnosed between the years 1987 and 2017, and all available family members. All index patients underwent next-generation sequencing for genetic variants in 174 target genes using the Illumina TruSight Cardio Sequencing Panel. Major adverse cardiac events (MACE) included mechanical circulatory support, heart transplantation, survivor of cardiac death, and/or all-cause death as combined endpoint.Results: Study population included 149 LVNC CMP patients with a median age of 27.8 (9.2–44.8) years at diagnosis; 58% of them were symptomatic, 18% suffered from non-sustained and sustained arrhythmias, and 17% had an implantable cardioverter defibrillator (ICD) implanted. 55/137 patients (40%) were ≤ 18 years at diagnosis.A total of 134 variants were identified in 87/113 (77%) index patients. 93 variants were classified as variant of unknown significance (VUS), 24 as likely pathogenic and 15 as pathogenic. The genetic yield of (likely) pathogenic variants was 35/113 (31%) index patients. Variants occurred most frequently in MYH7 (n=19), TTN (n = 10) and MYBPC3 (n = 8). Altogether, sarcomere gene variants constituted 42.5% (n = 57) of all variants. The presence or absence of (likely) pathogenic variants or variants in specific genes did not allow risk stratification for MACE.Reduced left ventricular (LV) systolic function and increased left ventricular end-diastolic diameter (LVEDD) were risk factors for event-free survival in the Kaplan-Meier analysis. Through multivariate analysis we identified reduced LV systolic function as the main risk factor for MACE. Patients with reduced LV systolic function were at a 4.6-fold higher risk for MACE.Conclusions: Genetic variants did not predict the risk of developing a MACE, neither in the pediatric nor in the adult cohort. Multivariate analysis emphasized reduced LV systolic function as the main independent factor that is elevating the risk for MACE. Genetic screening is useful for cascade screening to identify family members at risk for developing LVNC CMP.

Predictive value of global longitudinal strain and geometry of left ventricle in patients with noncompaction cardiomyopathy

Aim. To assess the prognostic role of a decrease in longitudinal strain and an increase in the left ventricular sphericity index as predictors of NYHA class III heart failure (HF) progression, requiring hospitalization in a cohort of patients with noncompaction cardiomyopathy (NCM) in combination with dilated cardiomyopathy (DCM).Material and methods. We examined 90 patients with a combination of NCM and DCM aged 18 to 72 years (median age, 41 years; men — 73; women — 17), who, in addition to conventional echocardiographic and magnetic resonance imaging (MRI) characteristics, were studied for two-dimensional strain and global longitudinal strain (GLS) parameters and left ventricular sphericity index (SI) using cardiac MRI. The endpoints included NYHA class III HF progression, requiring hospitalization.Results. During the follow-up period (median follow-up, 36 (6; 152) months) in 59 of 90 (65,5%) patients with NCM in combination with DCM, symptoms progressed to NYHA class III HF, requiring hospitalization. Multivariate analysis showed following independent risk factors for HF-related hospitalization: a decrease in GLS <10% (hazard ratio (HR), 5,1; 95% confidence interval (CI), 1,6-16,7, p<0,007) and an increase in SI >0,5 (HR, 9,0; 95% CI, 2,2-37,8, p<0,003) .The 3-year event-free survival rate for patients with one risk factor (GLS, %<10 and SI <0,5; GLS, %>10 and SI >0,5) was 79,2±16,9% and 64,4±24,6%, respectively, while for the group with two risk factors (GLS, %<10 and SI>0,5) — 12,3%.Conclusion. Global longitudinal strain characteristics according to 2D Strain echocardiography and SI according to cardiac MRI are associated with adverse events in NCM and DCM combination and can be used to identify patients with a high risk of HF progression to NYHA class III, requiring hospitalization.

Prenatal diagnosis of feta noncompaction cardiomyopathy with de novo CALM2 mutation

We report what apprears to be the first case of fetal noncompaction cardiomyopathy in both ventricles accompanied by a mutation in the calmodulin gene (CALM2): A 25-year-old woman was referred to our hospital at 25+1 weeks of gestation for evaluation of fetal defects. A postnatal echocardiography showed biventricular noncompaction cardiomyopathy. After terminated the pregnancy, fetal noncompaction cardiomyopathy was comfirmed by autopsy and histopathologic examination. And the whole-exome sequencing of genomic DNA demonstrated a de novo heterozygous mutation (c.389A>G;p.D130G) in CALM2, whereas the parents were normal. In this case report, we highlight the gene mutation in noncompaction cardiomyopathy.