Isolated ventricular non-compaction of the myocardium in adults

Isolated ventricular non-compaction ( IVNC) is a cardiomyopathy caused by intrauterine arrest of compaction of the myocardial fibres and meshwork, an important process in myocardial development.(1) During intrauterine life, deep intertrabecular recesses communicating with the ventricular endocardium evolve. Subsequently, the myocardium condenses and the intertrabecular recesses are converted to capillaries.(2) IVNC is characterised by the presence of deep intertrabecular recesses in hypertrophied and often hypokinetic segments of the myocardium of the left ventricle. By definition, IVNC occurs in the absence of other structural heart disease.(3) Owing both to heterogeneity in its clinical presentation and to simple ignorance, IVNC may often be undiagnosed. The objective of this review, therefore, is to clarify all relevant clinical, diagnostic, pathoanatomical and genetic aspects of IVNC in adults and to discuss emerging concepts regarding this disease. Previous clinical IVNC studies have been done on relatively small patient cohorts, and those studies were virtually all observational and retrospective in design. Prospective randomised clinical trials have not been conducted to date. The whole IVNC literature was previously based, to a considerable extent, on case reports sometimes of just one or a few patients.(4-8) Most of the case reports were published during the past decade, reflecting the increasing awareness of this disease. However, this review is essentially based on available studies of larger patient series and with statistical analysis. In addition, we use our own extensive experience with the diagnosis of the disease over 20 years to assess the literature critically.