Atrial septal defect associated with suspected left ventricular non-compaction supported by histopathological findings in a child

Left ventricular non-compaction (LVNC) is a rare cardiomyopathy characterized by excessive trabeculation of the left ventricular myocardium. The debate over whether LVNC is a distinct disease entity limits the estimates on its prevalence and incidence as there is a significant overlap with other known cardiomyopathies like hypertrophic cardiomyopathy, apical hypertrophy, and dilated cardiomyopathy. This condition is defined by excessive trabeculation of the myocardium, with deep intertrabecular recesses that communicate directly with the ventricular cavity. We report an 11-year-old boy with ostium secundum atrial septal defect (ASD), unexplained left ventricular dysfunction, and intraoperative findings suggestive of LVNC, in whom histopathological examination provided supportive evidence for the diagnosis. The decision for fenestrated ASD closure was based on reduced left ventricular compliance demonstrated during preoperative assessment. This case highlights the diagnostic challenges of LVNC when classical echocardiographic criteria are not fulfilled and emphasizes the complementary role of histopathological findings in selected cases.