Accepted as an unclassified cardiomyopathy by the American Heart Association or a genetic cardiomyopathy by the European Society of Cardiology, left ventricular non-compaction is an intriguing, but poorly understood condition characterized by the presence of a non-compacted extensive myocardial layer lining the cavity of the left ventricle which potentially leads to malignant arrhythmias, cardiac failure, and thromboembolism. Whether it is distinct cardiomyopathy or a morphological heterogeneous clinical condition with phenotypic morphologic traits often overlapping other types of cardiomyopathies remains very much debated. Ventricular trabeculation and compaction are two of the many essential steps for generating a functionally competent ventricular wall whereas, hyper trabeculation and the lack of ventricular wall compaction (non-compaction) are also one of the significant cardio-embryogenic defects associated with left ventricular noncompaction. This chapter aims to discuss in detail the current knowledge on embryology, epidemiology, clinical spectrum, genetics as both an isolated trait, and as part of other cardiac diseases or complex syndromes. It also explains the physiology, and the present pathophysiological concepts of non-compaction cardiomyopathy, provide an up-to-date view on imaging and also reevaluate the current diagnostic criteria and its impact on overdiagnosis of left ventricular non-compaction as well as the available data on prognosis, and therapy. The chapter will even go further to describe the challenges, and uncertainties facing the medical community, and the future directions in diagnosing left ventricular non-compaction.
Keywords: Cardiomyopathy, Congenital heart disease, Cardiac magnetic resonance, Cardiac computed tomography, Counseling, Diagnosis, Diagnostic accuracy, Epidemiology, Echocardiography, Genetics, Genetic testing, Heart failure, Heart ventricles, Imaging, Left ventricular non-compaction, Myocardium, Myocardial fibrosis, Mitochondrial myopathies, Non-compaction, Pathology, Pregnancy, Prognosis, Right ventricular non-compaction, Spongy myocardium, Trabeculae.