Left ventricular non-compaction: genetic heterogeneity, diagnosis and clinical course.

Left ventricular non-compaction (LVNC) is a rare disorder that results in multiple deep trabeculations within the left ventricular myocardium. It is thought to be due in part, to an arrest of myocardial development but more recent evidence suggests that some cases may actually be acquired while other isolated cases have regressed with time. Transthoracic echocardiography remains the imaging modality of choice for LVNC where diagnosis is based on the identification of multiple prominent ventricular trabeculations with intertrabecular spaces communicating with the ventricular cavity. There is a broad and potentially confusing spectrum of clinical symptomatology in patients with ventricular non-compaction meaning that the primary diagnosis is often missed. Complications such as potentially malignant arrhythmias, left ventricular failure, and cardioembolic events arising as a result of non-compaction must be treated in an attempt to decrease morbidity and mortality from this disorder. The ultimate outcome for patients remains unclear with some boasting a prolonged asymptomatic course, to others displaying a rapid deterioration of left ventricular systolic function, leading to heart transplantation or death. In conclusion, LVNC while remaining a rare cardiomyopathy, shall probably be diagnosed with increasing frequency in the coming years because of heightened awareness about its natural history and clinical manifestations and because of the improved modalities available for cardiac imaging.