Diagnostic Cardiovascular Magnetic Resonance Imaging Criteria in Noncompaction Cardiomyopathy and the Yield of Genetic Testing.

BACKGROUND: Noncompaction cardiomyopathy (NCCM) is characterized by a thickened myocardial wall with excessive trabeculations of the left ventricle, and ∼30% is explained by a (likely) pathogenic variant [(L)PV] in a cardiomyopathy gene. Diagnosing an (L)PV is important because it allows accurate identification of which relatives are at risk and helps predicting prognosis. The goal of this study was to assess which specific clinical and morphologic characteristics of the myocardium may predict an (L)PV and which of the cardiovascular magnetic resonance (CMR) diagnostic criteria for NCCM can best be used for that purpose. METHODS: Sixty-two patients with NCCM, diagnosed by means of echocardiographic Jenni criteria, underwent CMR imaging that was evaluated according the Petersen, Stacey, Jacquier, Captur, and Choi diagnostic CMR criteria for NCCM. Patients also underwent DNA testing and were stratified according to having an (L)PV. RESULTS: Thirty-three patients (53%) with NCCM had an (L)PV. The apical and mid-lateral segments were the dominant locations for meeting Petersen and/or Stacey criteria. Correlation between different CMR criteria varied from moderate to very strong. In multivariate binary logistic regression analysis with CMR and non-CMR parameters, independent positive predictors for an (L)PV were familial cardiomyopathy, trabecular mass, and meeting Petersen criteria in ≥ 2 out of 3 long-axis views, whereas left bundle branch block and hypertension were negative predictors. The receiver operating characteristic curve of this multivariate model had an area under the curve of 0.89 (95% confidence interval 0.82-0.97). CONCLUSIONS: CMR criteria together with family history help to distinguish those patients in whom an (L)PV can be identified, consequently leading to referral for genetic diagnostics and cascade screening.

Cardiovascular Magnetic Resonance in Heritable Cardiomyopathies.

Cardiovascular magnetic resonance represents the imaging modality of choice for the investigation of patients with heritable cardiomyopathies. The combination of gold-standard volumetric analysis with tissue characterization can deliver precise phenotypic evaluation of both cardiac morphology and the underlying myocardial substrate. Cardiovascular magnetic resonance additionally has an established role in risk-stratifying patients with heritable cardiomyopathy and an emerging role in guiding therapies. This article explores the application and utility of cardiovascular magnetic resonance techniques with specific focus on the major heritable cardiomyopathies.

Genetic Testing for Inherited Cardiovascular Diseases: A Scientific Statement From the American Heart Association.

Advances in human genetics are improving the understanding of a variety of inherited cardiovascular diseases, including cardiomyopathies, arrhythmic disorders, vascular disorders, and lipid disorders such as familial hypercholesterolemia. However, not all cardiovascular practitioners are fully aware of the utility and potential pitfalls of incorporating genetic test results into the care of patients and their families. This statement summarizes current best practices with respect to genetic testing and its implications for the management of inherited cardiovascular diseases.

Evaluation of Clinical Practices Related to Variants of Uncertain Significance Results in Inherited Cardiac Arrhythmia and Inherited Cardiomyopathy Genes.

BACKGROUND: Increasing use of genetic tests have identified many variants of uncertain significance (VUS) in genes associated with inherited arrhythmias and cardiomyopathies. Evaluation of clinical practices, including medical management recommendations for VUS patients and their families, is important to prevent over- or under-treatment that may result in morbidity or mortality. The purpose of this study is to describe practices related to VUS results including information and medical management recommendations providers give patients and their families. METHODS: An anonymous online survey was distributed to genetic counselors (GCs) and cardiologists who have seen at least one patient for inherited arrhythmias or cardiomyopathies. The survey explored providers' confidence in counseling, explanation of VUSs, topics covered before and after genetic testing, and clinical recommendations using a hypothetical scenario maximizing uncertainty with an unclear clinical and molecular diagnosis. Descriptive statistics were calculated, and median confidence and likelihood of making various medical recommendations were compared across provider type. RESULTS: Providers (N=102) who completed the survey included 29 cardiovascular GCs, 50 GCs from other specialties, and 23 cardiologists. GCs feel more confident than cardiologists counseling about VUS results (P<0.001); while both cardiovascular GCs and cardiologists feel more confident than other GCs in providing input regarding medical management recommendations (P=0.001 and P=0.01, respectively). Cardiologists were more likely than cardiac GCs to recommend clinical testing for family members even though testing in the scenario is expected to be uninformative. CONCLUSIONS: These findings illustrate how the expertise of different providers may impact decision processes, suggesting the need for interdisciplinary clinics to optimize care for challenging cases.

Improved Criteria for the Classification of Titin Variants in Inherited Skeletal Myopathies.

BACKGROUND: Extensive genetic screening results in the identification of thousands of rare variants that are difficult to interpret. Because of its sheer size, rare variants in the titin gene (TTN) are detected frequently in any individual. Unambiguous interpretation of molecular findings is almost impossible in many patients with myopathies or cardiomyopathies. OBJECTIVE: To refine the current classification framework for TTN-associated skeletal muscle disorders and standardize the interpretation of TTN variants. METHODS: We used the guidelines issued by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) to re-analyze TTN genetic findings from our patient cohort. RESULTS: We identified in the classification guidelines three rules that are not applicable to titin-related skeletal muscle disorders; six rules that require disease-/gene-specific adjustments and four rules requiring quantitative thresholds for a proper use. In three cases, the rule strength need to be modified. CONCLUSIONS: We suggest adjustments are made to the guidelines. We provide frequency thresholds to facilitate filtering of candidate causative variants and guidance for the use and interpretation of functional data and co-segregation evidence. We expect that the variant classification framework for TTN-related skeletal muscle disorders will be further improved along with a better understanding of these diseases.

Cardiac resynchronization therapy improves heart failure in one patient with acromegaly-induced cardiomyopathy: a case report.

BACKGROUND: Congestive heart failure is rarely observed in patients with acromegaly. Excessive growth hormone secretion and elevation of insulin-like growth factor 1 contribute to pathological changes in myocyte growth and structure, cardiac contractility, vascular function, and in later stage may progress to cardiac dysfunction. Early recognition of the condition is paramount, though the insidious progression of the disease commonly results in late diagnosis. Current standard regimens of pharmacological therapy, surgical treatment, radiotherapy are designed to normalize serum levels of both insulin-like growth factor 1 and growth hormone. In patients with late-stage heart failure due to acromegalic cardiomyopathy, cardiac resynchronization therapy might be a desirable treatment to help cardiac synchronization, improve symptoms, and eventually reduce hospital admissions together with mortality rates. CASE PRESENTATION: We describe a case of a 49-year-old man with a history of acromegaly who presented to our hospital with a diagnosis of decompensated systolic heart failure. Serial electrocardiograms showed wide (160-200 ms) QRS duration with left bundle branch block. Echocardiography showed severe left ventricular dysfunction that simultaneously achieved a left ventricular ejection fraction of 16%. Surgical indication was rarely assessed by neurosurgeons. Given that the stereotactic radiosurgery together with pharmacotherapy produced infinitesimal effects, cardiac resynchronization therapy was performed. Owing to biventricular synchronization and holding back reverse remodeling, the patient's symptoms were successfully alleviated, and he was discharged from the hospital. CONCLUSIONS: Congestive heart failure is a rare complication in acromegaly-induced cardiomyopathy (occurs in only 3% of patients). Early diagnosis and treatment with curative drugs more than cardiovascular implantable electronic devices might lead to better surgical outcomes in this group of patients.

Seguimiento a largo plazo de pacientes sintomáticos adultos con miocardiopatía no compactadal / Long-term follow-up of symptomatic adult patients with noncompaction cardiomyopathy

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Anaesthetic Management of a Patient with Left Ventricular Non-Compaction Undergoing Laparotomy.

We report a case of left ventricular non-compaction as patient underwent laparotomy for ovarian cystectomy. Left ventricular non-compaction is a rare congenital cardiomyopathy with clinical features of heart failure, systemic thromboembolic events and arrhythmias. Perioperative management of these patients can be very challenging. We used general anaesthesia with subarachnoid block for our patient. We used perioperative, goal-directed, fluid therapy using LiDCO rapid in this case. Patient was monitored in high dependency unit for the risk of perioperative arrhythmias and discharged home in next 24 hours.

Compound heterozygous loss-of-function mutations in KIF20A are associated with a novel lethal congenital cardiomyopathy in two siblings.

Congenital or neonatal cardiomyopathies are commonly associated with a poor prognosis and have multiple etiologies. In two siblings, a male and female, we identified an undescribed type of lethal congenital restrictive cardiomyopathy affecting the right ventricle. We hypothesized a novel autosomal recessive condition. To identify the cause, we performed genetic, in vitro and in vivo studies. Genome-wide SNP typing and parametric linkage analysis was done in a recessive model to identify candidate regions. Exome sequencing analysis was done in unaffected and affected siblings. In the linkage regions, we selected candidate genes that harbor two rare variants with predicted functional effects in the patients and for which the unaffected sibling is either heterozygous or homozygous reference. We identified two compound heterozygous variants in KIF20A; a maternal missense variant (c.544C>T: p.R182W) and a paternal frameshift mutation (c.1905delT: p.S635Tfs*15). Functional studies confirmed that the R182W mutation creates an ATPase defective form of KIF20A which is not able to support efficient transport of Aurora B as part of the chromosomal passenger complex. Due to this, Aurora B remains trapped on chromatin in dividing cells and fails to translocate to the spindle midzone during cytokinesis. Translational blocking of KIF20A in a zebrafish model resulted in a cardiomyopathy phenotype. We identified a novel autosomal recessive congenital restrictive cardiomyopathy, caused by a near complete loss-of-function of KIF20A. This finding further illustrates the relationship of cytokinesis and congenital cardiomyopathy.

Effect of therapeutic hypothermia on myocardial dysfunction in term neonates with perinatal asphyxia - a randomized controlled trial.

OBJECTIVE: To evaluate the effect of therapeutic hypothermia on myocardial dysfunction in term neonates with perinatal asphyxia. MATERIAL AND METHODS: This randomized controlled trial (RCT) conducted in a tertiary care teaching hospital, south India included 120 newborns with perinatal asphyxia that were randomized to two groups (therapeutic hypothermia and normothermia). Cardiac enzyme profile changes between groups were assessed at 0, 24, 72 h CPK-MB and troponin I levels were estimated by immune inhibition and quantitative immunochromatography methods, respectively. Electrocardiography (ECG) and Echocardiography (ECHO) were done at 0 and 72 h to evaluate the cardiac function and pulmonary hypertension. Neurodevelopment was assessed at 6 months of age in both groups using Developmental Assessment Scales for Indian Infants. RESULTS: The median values of CPK-MB in the normothermia and hypothermia groups at 0, 24, and 72 h were 198, 127, and 92 IU/L and 202, 111 and 64 IU/L, respectively. The median values of troponin I in normothermia and hypothermia groups at 0, 24, and 72 hrs were 2.45, 1.53, and 0.9 ng/mL and 1.97, 0.93, and 0.01 ng/mL, respectively. ECG and ECHO findings also suggest lesser myocardial dysfunction in therapeutic hypothermia group compared with the normothermia group. CONCLUSIONS: Therapeutic hypothermia significantly decreases the myocardial damage in term asphyxiated neonates.

Coexistence of congenital left ventricular aneurysm and prominent left ventricular trabeculation in a patient with LDB3 mutation: a case report.

BACKGROUND: The coexistence of congenital left ventricular aneurysm and abnormal cardiac trabeculation with gene mutation has not been reported previously. Here, we report a case of coexisting congenital left ventricular aneurysm and prominent left ventricular trabeculation in a patient with LIM domain binding 3 gene mutation. CASE PRESENTATION: A 30-year-old Asian man showed paroxysmal sinus tachycardia and Q waves in an electrocardiogram health check. There were no specific findings in physical examinations and serological tests. A coronary-computed tomography angiography check showed normal coronary artery and no coronary stenosis. Both left ventricle contrast echocardiography and cardiac magnetic resonance showed rare patterns of a combination of an apical aneurysm-like out-pouching structure with a wide connection to the left ventricle and prominent left ventricular trabecular meshwork. High-throughput sequencing examinations showed a novel mutation in the LDB3 gene (c.C793>T; p.Arg265Cys). CONCLUSIONS: Our finding indicates that the phenotypic expression of two heart conditions, congenital left ventricular aneurysm and prominent left ventricular trabeculation, although rare, can occur simultaneously with LDB3 gene mutation. Congenital left ventricular aneurysm and prominent left ventricular trabeculation may share the same genetic background.

Identification of a hybrid myocardial zone in the mammalian heart after birth.

Noncompaction cardiomyopathy is characterized by the presence of extensive trabeculations, which could lead to heart failure and malignant arrhythmias. How trabeculations resolve to form compact myocardium is poorly understood. Elucidation of this process is critical to understanding the pathophysiology of noncompaction disease. Here we use genetic lineage tracing to mark the Nppa+ or Hey2+ cardiomyocytes as trabecular and compact components of the ventricular wall. We find that Nppa+ and Hey2+ cardiomyocytes, respectively, from the endocardial and epicardial zones of the ventricular wall postnatally. Interposed between these two postnatal layers is a hybrid zone, which is composed of cells derived from both the Nppa+ and Hey2+ populations. Inhibition of the fetal Hey2+ cell contribution to the hybrid zone results in persistence of excessive trabeculations in postnatal heart. Our findings indicate that the expansion of Hey2+ fetal compact component, and its contribution to the hybrid myocardial zone, are essential for normal formation of the ventricular walls.Fetal trabecular muscles in the heart undergo a poorly described morphogenetic process that results into a solidified compact myocardium after birth. Tian et al. show that cardiomyocytes in the fetal compact layer also contribute to this process, forming a hybrid myocardial zone that is composed of cells derived from both trabecular and compact layers.