Left ventricular non-compaction: from recognition to treatment.

We have gained considerable insight and understanding about the etiology, embryogenesis of the myocardium, genetic background, diagnosis and outcome of left ventricular non-compaction (LVNC) over the last 2 decades. LVNC has a distinct morphological appearance with a thickened, two-layered myocardium consisting of an epicardial compacted and a thicker endocardial non-compacted layer. These features make the recognition with non-invasive imaging modalities highly feasible. We now recognize LVNC is a distinct phenotype of the myocardium with genetic heterogeneity. In several cases, LVNC shares a common genetic background with other forms of cardiomyopathy. Therefore, most likely it is not a distinct form of cardiomyopathy but rather a morphological expression of different diseases. LVNC can present as an isolated condition or associated with congenital heart disease, neuromuscular disease or genetic syndromes. It may be sporadic or a familial disease, with an autosomal dominant or X-linked mode of transmission. The clinical features associated with LVNC vary from asymptomatic individuals diagnosed during screening to symptomatic patients, with the potential for heart failure, arrhythmias, thromboembolic events, and sudden cardiac death. A comprehensive diagnostic approach includes clinical history, electrocardiogram, imaging (in many instances with more than one technique), genetic assessment, and screening of first-degree relatives. This increases the chances of instituting the most appropriate therapy. Therapy for the most part is very similar to the general heart failure population with the exception that anticoagulation is started at a lower threshold.