Isolated Noncompaction of the Left Ventricular Myocardium in Adults: A Systematic Overview

BackgroundOwing to inconsistent diagnostic criteria and small heterogeneous cohorts, little is known about the long-term outcomes of adult left ventricular noncompaction (LVNC), a rare cardiomyopathy with potentially serious outcomes. This systematic overview aimed to better delineate the natural history of adult LVNC.Method and ResultsA comprehensive computerized search using “noncompaction” and its synonyms initially identified 206 articles, with reference lists subsequently hand scanned. These searches yielded 5 studies that were eligible for this systematic overview, identifying adult cohorts with isolated LVNC diagnosed by similar echocardiographic criteria. This combined cohort (n = 241) was followed for a mean duration of 39 months. The annualized event rate was 4% for cardiovascular deaths, 6.2% for cardiovascular death and its surrogates (heart transplantation and appropriate implantable cardioverter-defibrillator shocks), and 8.6% for all cardiovascular events (death, stroke, implantable cardioverter-defibrillator shocks, and heart transplantation.) Familial occurrence of LVNC in first-degree relatives was identified by echocardiography in 30% of index cases who were screened.ConclusionLVNC is an increasingly recognized cardiomyopathy diagnosed by echocardiography and is associated with familial tendencies, arrhythmias, thromboembolism, advanced heart failure, and death.