Aims: Non-compaction of the left ventricular myocardium (NCVM) is reportedly exceedingly rare and associated with a high morbidity and mortality. A different genetic background has been suggested for NCVM with [non-isolated NCVM (ni-NCVM)] and without [isolated NCVM (i-NCVM)] other congenital heart defects. We prospectively evaluated both the NCVM subgroups regarding frequency of occurrence and cardiovascular complications in a paediatric population. Results In a prospective, single-centre study, 66/5220 consecutive patients (1.26%) were diagnosed (25 i-NCVM, 41 ni-NCVM). The median age was 4 years (range 0-21), the median follow-up 12 months (range 0-51). The occurrence of congestive heart failure (CHF) at follow-up was 68.0%. CHF was as frequently seen in i-NCVM and ni-NCVM patients (77.5 vs. 62.1%, P = 0.322). The occurrence of arrhythmias (20.0%) and thrombo-embolic events (13.9%) was not different between subgroups. The cardiomyopathy related mortality was 7.1%, with three and one deaths in the i-NCVM and ni-NCVM groups, respectively (P = 0.126).
Conclusion: When prospectively evaluated, NCVM appears to have been previously under-diagnosed. Whereas arrhythmias and thrombo-embolic events were rare, CHF was frequently found. An equally aggressive anticongestive treatment regimen would seem indicated for both the NCVM subgroups.