Sudden Death and Isolated Right Ventricular Noncompaction Cardiomyopathy: Report of 2 Autopsied Adult Cases

NON-COMPACTION CARDIOMYOPATHY: ISSUES, CONTRADICTIONS AND SEARCH FOR EFFECTIVE DIAGNOSTIC CRITERIA. LITERATURE REVIEW. PART 1

Active research of non-compaction cardiomyopathy (NCM) has been going on for more than 30 years. A significant amount of information has been accumulated that is familiar to a much larger number of specialists than in the most recent past. Despite this, numerous issues remain unresolved, ranging from classification (congenital or acquired, nosology or morphological phenotype) to the ongoing search for clear diagnostic criteria that separate NCM from physiological hypertrabecularity and secondary non-compaction myocardium with the background of existing chronic processes. Meanwhile, a high risk of adverse cardiovascular events in a certain group of people with NCM is quite high. These patients need timely and often quite aggressive therapy. This review of sources of scientific and practical information is devoted to the current aspects of the classification, extremely diverse clinical picture, extremely complex genetic and instrumental diagnosis of NCM, and the possibilities of its treatment. The purpose of this review is to analyze current ideas about the controversial problems of non-compaction cardiomyopathy. The material for its preparation is the numerous sources of databases Web Science, PubMed, Google Scholar, eLIBRARY. As a result of their analysis, the authors tried to identify and summarize the main problems of the NCM and identify the ways to resolve them.

Non-compact right ventricular myocardium – diagnostic and clinical features: A review

Non-compact right ventricular myocardium is a rare type of cardiomyopathy, it usually results from arrested myocardial development during embryogenesis. This disease can be characterized by excessive prominent trabeculations and deep inter-trabecular recesses in the ventricular wall. It might be a component of biventricular non-compact cardiomyopathy or an isolated form. The article presents a review of the literature on the clinic and radiation diagnostics of non-compact right ventricular myocardium with the presentation of the issues of differential diagnosis.

Higher spatial resolution improves the interpretation of the extent of ventricular trabeculation

The ventricular walls of the human heart comprise an outer compact layer and an inner trabecular layer. In the context of an increased pre-test probability, diagnosis left ventricular noncompaction cardiomyopathy is given when the left ventricle is excessively trabeculated in volume (trabecular vol >25% of total LV wall volume) or thickness (trabecular/compact (T/C) >2.3). Here, we investigated whether higher spatial resolution affects the detection of trabeculation and thus the assessment of normal and excessively trabeculated wall morphology. First, we screened left ventricles in 1112 post-natal autopsy hearts. We identified five excessively trabeculated hearts and this low prevalence of excessive trabeculation is in agreement with pathology reports but contrasts the prevalence of approximately 10% of the population found by in vivo non-invasive imaging. Using macroscopy, histology and low- and high-resolution MRI, the five excessively trabeculated hearts were compared with six normal hearts and seven abnormally trabeculated and excessive trabeculation-negative hearts. Some abnormally trabeculated hearts could be considered excessively trabeculated macroscopically because of a trabecular outflow or an excessive number of trabeculations, but they were excessive trabeculation-negative when assessed with MRI-based measurements (T/C <2.3 and vol <25%). The number of detected trabeculations and T/C ratio were positively correlated with higher spatial resolution. Using measurements on high resolution MRI and with histological validation, we could not replicate the correlation between trabeculations of the left and right ventricle that has been previously reported. In conclusion, higher spatial resolution may affect the sensitivity of diagnostic measurements and in addition could allow for novel measurements such as counting of trabeculations.

Three Myocardial Diseases in One Heart: Arrhythmogenic Right Ventricular Cardiomyopathy, Left Ventricular Noncompaction and Myocarditis

Purpose: To evaluate the clinical features, laboratory and instrumental tests results and the effectiveness of complex treatment in a patient with multiple etiologies of dilated cardiomyopathy (DCM) with a high risk of sudden cardiac death. Methods: Female patient was 34 years old. Follow up period was seven years. Since the age of 23 (after a respiratory infection), chest pains and shortness of breath appeared. Coronary arteries were intact. After syncope in 2013, Holter-ECG was performed: 2048 premature ventricular beats (PVBs)/day and episode of sustained ventricular tachycardia (VT, 1 min) were registered. MRI was performed, and a cardioverter defibrillator (ICD) was implanted. Results: ECG showed low QRS voltage and negative T waves in leads V2-V6, III, aVF. In signal-averaged ECG, late potentials were detected. Echocardiography (EchoCG) demonstrated left and right ventricular dilatation, diffuse reduction of left ventricular (LV) contractility and multiple pseudochordae in LV. MRI showed LV noncompaction (LVNC), thickening of the epicardial fat and hypo-/dyskinesia of the anterior wall of the right ventricular (RV), dilatation of both ventricles with decrease of their ejection fraction and subepicardial gadolinium enhancement in the early and late phase in the LV, intraventricular septum and the free walls of the RV. The presence of LVNC was confirmed by cardiac computed tomography (CT). Late contrast enhancement in the middle and subendocardial layer of the LV was observed as well. The level of anticardiac antibodies was high (1:160–1:320). The reasons for statement of a possible diagnosis of myocarditis in this case were the connection of the onset of symptoms with viral infection, high titers of anticardiac antibodies, and early and late subepicardial contrast enhancement by MRI and CT. The endomyocardial biopsy was obtained, and subendocardial lipomatosis, separation of myocardium by fibrous septa, lymphocytic infiltrates (more than 14 cells/mm2) and vasculitis were found. Viral genome in myocardium was not detected. A new splicing mutation in the desmoplakin (DSP) gene was found (NM_004415.4: c.1141-2A>G/N (rs794728111)). Combination of arrhythmogenic right ventricular cardiomyopathy (ARVC), LVNC and myocarditis was diagnosed. Immunosuppressive therapy (prednisone and azathioprine) was prescribed, LV ejection fraction stabilized at the level of 40%. The appropriate shocks of the ICD due to sustainedVT (HR 210/min) with transformation into ventricular fibrillation were recorded twice. For this reason, sotalol was temporarily replaced with amiodarone. After the suppression of myocarditis activity, sustained VT and ICD interventions were not observed. Conclusions: In a young patient with arrhythmogenic syncope and DCM syndrome, a combination of ARVC (two major and three minor criteria, definite diagnosis) and LVNC with the biopsy proved virus-negative chronic myocarditis was diagnosed. DCM as a syndrome can have multiple causes, and the combination of myocarditis and primary cardiomyopathy is not rare. LVNC can be observed in patients with typical desmosomal protein mutations. The use of immunosuppressive therapy led to the stabilization of heart failure and decreased the risk of arrhythmic events.

Arrhythmogenic Noncompaction Cardiomyopathy: Is There an Echocardiographic Phenotypic Overlap of Two Distinct Cardiomyopathies?

The clinical diagnosis of right ventricular (RV) cardiomyopathies is often challenging. It is difficult to differentiate the isolated left ventricular (LV) noncompaction cardiomyopathy (NC) from biventricular NC or from coexisting arrhythmogenic ventricular cardiomyopathy (AC). There are currently few established morphologic criteria for the diagnosis other than RV dilation and presence of excessive regional trabeculation. The gross and microscopic changes suggest pathological similarities between, or coexistence of, RV-NC and AC. Therefore, the term arrhythmogenic right ventricular cardiomyopathy is somewhat misleading as isolated LV or biventricular involvement may be present and thus a broader term such as AC should be preferred. We describe an unusual case of AC associated with a NC in a 27-year-old man who had a history of permanent pacemaker 7 years ago due to second-degree atrioventricular block.

Left ventricular noncompaction: a distinct cardiomyopathy or a trait shared by different cardiac diseases?

Whether left ventricular noncompaction (LVNC) is a distinct cardiomyopathy or a morphologic trait shared by different cardiomyopathies remains controversial. Current guidelines from professional organizations recommend different strategies for diagnosing and treating patients with LVNC. This state-of-the-art review discusses new insights into the basic mechanisms leading to LVNC, its clinical manifestations, treatment modalities, anatomy and pathology, embryology, genetics, epidemiology, and imaging. Three markers currently define LVNC: prominent left ventricular trabeculae, deep intertrabecular recesses, and a thin compacted layer. Although new genetic data from mice and humans supports LVNC as a distinct cardiomyopathy, evidence for LVNC as a shared morphological trait is not ruled out. Criteria supporting LVNC as a shared morphological trait may depend on consensus guidelines from the multiple professional organizations. Enhanced imaging and increased use of genetics are both predicted to significantly impact our overall understanding of the basic mechanisms causing LVNC and its optimal management.