Left Ventricular Noncompaction

Abstract

LVNC is a relatively recently defined, genetically heterogeneous, cardiomyopathy. Clinical presentation and prognosis range from asymptomatic disease with no or slow progression, to severe disabling, rapidly progressive heart failure. Initial presentation includes the triad of heart failure, (potentially lethal) arrhythmias and/or thrombo-embolism. LVNC may occur at all ages, even prenatally. In childhood, clinical features are often more severe and LVNC is frequently associated with congenital heart defects. In adults, the majority of LVNC is isolated. The echocardiographic diagnostic criteria as proposed by Jenni et al. are currently the most widely applied. General cardiac guidelines for chronic heart failure and ICDs are applicable to the LVNC population. In approximately 40% of patients with isolated LVNC, molecular testing may yield a genetic (mostly sarcomere) defect, with MYH7 as the most prevalent disease gene. The nonisolated forms of LVNC are caused by a range of rare genetic defects. Until now, in half of familial isolated LVNC, the genetic defect remains unknown. Genetic defects in a large number of sarcomere and other cardiomyopathy genes and in genes primarily associated with skeletal myopathies indicate that LVNC may result from a wide range of pathophysiologic mechanisms. Shared genetic defects and familial aggregation of LVNC, HCM and DCM indicate that LVNC may be part of a broad spectrum of cardiomyopathies. The genetic aetiology of LVNC requires that patients and their relatives are offered genetic testing and counselling. This may include (predictive) molecular analysis of relatives, when applicable, and/or cardiac evaluation of at-risk relatives, even when they are as yet asymptomatic.