• Myocardial Disease

Non-compaction cardiomyopathy (NCM) is a myocardial disorder, which is thought to occur due to the failure of left ventricle (LV) compaction during embryogenesis, leading to distinct morphological characteristics in the ventricular chamber.1 It was first described about 80 years ago, in association with complex congenital heart diseases. More recently, Chin et al2 reported the isolated form of non-compaction LV, and since then many other reports have been published. The involvement of the right ventricle in the non-compaction process has been increasingly identified and the condition is now included among the cardiomyopathies. The nomenclature of this entity has been variable, being known as ‘spongy myocardium’ or ‘persistent embryonic myocardium’, but more frequently known as ‘LV non-compaction’ or NCM. Therefore, the latter term will be the one used in this article.

The characteristic features of NCM have been described as including a two-layered ventricular wall, comprising a thinner compact epicardial layer and an inner non-compacted layer, with prominent trabeculations associated with deep, intertrabecular recesses that communicate with the ventricular cavity but not with the coronary circulation.2 ,3 The in vivo diagnosis requires the detection of these typical characteristics using imaging techniques.2 ,3 However, there has been considerable controversy regarding the differentiation from normal LV trabeculation and the relationship with other cardiomyopathies, such as dilated and hypertrophic cardiomyopathies, which may share the same genetic basis and be associated with NCM.

The prevalence of NCM varies considerably among different series and is still unknown. Several limitations for this assessment are the different diagnostic criteria, the heterogeneous populations, and the retrospective design of most studies. The reported prevalence of NCM in patients referred to echocardiography laboratories ranges between 0.014–1.26%,4 while in a population based retrospective study in children NCM accounted for 9.5% among cardiomyopathies,5 and in a large …