AIMS: Non-compaction of the left ventricle (LVNC) is a disorder of 
endomyocardial morphogenesis that results in multiple trabeculations in the left 
ventricular myocardium. The current literature suggests that LVNC in adults is 
rare and associated with a poor prognosis. Given that the disorder is present at 
birth and that several studies have reported asymptomatic familial disease in 
some patients, we hypothesized that there is a long pre-clinical phase of the 
disease. The aim of this study was to define the prognosis and familial 
incidence of LVNC.
METHODS AND RESULTS: This study cohort comprised 45 patients (mean age at 
diagnosis 37 years) consecutively identified at a referral centre for 
cardiomyopathy over a 10-year period. Twenty-eight patients (62%) had dyspnoea 
at presentation; 41 (91%) an abnormal ECG; and 30 (66%) left ventricular 
dilatation and impaired systolic function. Nine patients (20%) had non-sustained 
ventricular tachycardia on 24 h Holter monitoring. Mean survival from death or 
transplantation was 97% at 46 months. There were three thromboembolic events in 
two patients (4%). On systematic family screening, 8 of 32 (25%) asymptomatic 
relatives had a range of echocardiographic abnormalities, including LVNC, LVNC 
with impaired systolic function, and left ventricular enlargement without LVNC.
CONCLUSION: This study demonstrates that LVNC is associated with a better 
prognosis than previously reported. In patients with familial disease, relatives 
may have features consistent with dilated cardiomyopathy rather than LVNC.