Natural history and familial characteristics of isolated left ventricular non-compaction.

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.