Ventricular non‐compaction cardiomyopathy: prenatal diagnosis and pathology

OBJECTIVE: The objective of this study is to evaluate the prenatal diagnosis of ventricular non-compaction cardiomyopathy (NCCM) and to report the pathologic features and the characteristic myocardial ultrastructure of fetal NCCM. METHOD: We examined nine cases of fetal NCCM by prenatal echocardiography from 2004 to 2013. These cases were evaluated with respect to prenatal diagnosis, outcomes, pathology, and characteristics of the myocardial ultrastructure. RESULTS: Trabeculated myocardium and non-compaction/compaction ratio (N/C ratio) ≥2.0 is the echocardiographic feature that allowed diagnosis. Among the nine fetuses with a prenatal diagnosis of NCCM, six were diagnosed with left ventricular non-compaction (LVNC), two with non-compaction of both ventricles (biventricular NCCM), and one with right ventricular non-compaction. Among the nine fetuses, the LVNC diagnosis was confirmed by postnatal echocardiography in 2; the other patients chose to terminate their pregnancies, and those cases were confirmed at autopsy. Muscle biopsies were performed on three of the aborted fetuses, and abnormal mitochondria, sarcomeres, and myocardial fibers were observed. CONCLUSION: Non-compaction can be identified in the fetus. Fetal non-compaction most often involves the left ventricle, but can involve the right ventricle or both ventricles. The myocardial ultrastructure of fetal ventricular non-compaction has certain unique characteristics regarding the maturation of the mitochondria, sarcomeres, and myocardial fibers.