Neonatal Sudden Death Due to Histiocytoid Cardiomyopathy

Histiocytoid cardiomyopathy, an extremely rare heart disease in infants and children, usually occurring in girls under the age of 2 years, is characterized by cardiomegaly, ventricular arrhythmia, and sudden death. In the present study, we report a case of a 2-day-old female neonate who suddenly showed cyanosis and cardiac arrest in the neonatal unit and died without resuscitation. Autopsy revealed multifocal nodular lesions in the left ventricle wall and papillary muscles. Microscopically, these lesions were composed of discohesive round or polygonal cells with eosinophilic cytoplasm and were positive for desmin and negative for CD68. Electron microscopy findings displayed abnormal swollen mitochondria with disorganized cristae, dense granules, and diminished myofibrils in the periphery of the cytoplasm.

Successful catheter ablation of premature ventricular contractions triggering torsade de pointes in a small infant with histiocytoid cardiomyopathy: a case report

Background A short-coupled variant of torsade de pointes (ScTdP) is rare and resistant to medical treatment. There has not been a reported catheter ablation (CA) of a short-coupled premature ventricular contraction (PVC) triggering ScTdP in an infant. Case summary A neonate was referred to our hospital on the day of birth for Wolff–Parkinson–White syndrome, repeated episodes of supraventricular tachycardia, and a left ventricular non-compaction. She underwent CA of an accessory pathway at 72 days of age. On the 5th day after ablation, she had recurrent TdP episodes resistant to various antiarrhythmic drugs and received extracorporeal membrane oxygenation at 86 days of age. She underwent CA of PVCs triggering TdP at 122 days of age and a weight of 3.4 kg. Two types of PVCs triggering TdP were successfully ablated, which originated from the right ventricle (RV). Pre-potentials were recorded at the earliest ventricular activation sites of the targeted PVCs. After the ablation, she had no TdP episodes and the cardiac assist device was removed. However, she died of uncontrolled heart failure at 6 months of age. The histological findings were compatible with histiocytoid cardiomyopathy and abnormal cells were distributed throughout both ventricles. At the ablation site, fibrotic transmural lesions were noted in the RV wall. Discussion The PVCs triggering TdP were successfully ablated in a 4-month-old girl with histiocytoid cardiomyopathy. The PVCs were likely caused by triggered activity and associated with abnormal Purkinje cells.