Histiocytoid cardiomyopathy

Histiocytoid cardiomyopathy (also known as infantile cardiomyopathy with histiocytoid change, foamy myocardial transformation of infancy, or oncocytic cardiomyopathy) is an extremely rare and often fatal cardiac disorder that predominantly affects infants and young children, with a notable female predominance. The condition is characterized by the presence of abnormal cells within the heart muscle that resemble histiocytes (a type of immune cell) but are actually altered cardiac myocytes filled with abnormal mitochondria. These cells disrupt normal cardiac conduction and contractile function. The disease primarily affects the heart, leading to life-threatening arrhythmias (including ventricular tachycardia, ventricular fibrillation, and supraventricular tachycardia), cardiac arrest, and sudden death. Some patients may also present with cardiomegaly, heart failure, or Wolff-Parkinson-White syndrome. Extracardiac manifestations have occasionally been reported, including involvement of the eyes and central nervous system. The condition has been associated with mutations in mitochondrial DNA-encoded genes, particularly in the cytochrome b gene (MT-CYB), as well as nuclear genes involved in mitochondrial function such as NDUFB11, suggesting a mitochondrial etiology. Treatment options are limited and largely supportive. Management focuses on controlling arrhythmias with antiarrhythmic medications, and in some cases, surgical excision of the abnormal myocardial tissue (if focal lesions are identified) or cardiac transplantation may be considered. Despite intervention, the prognosis remains poor, with many cases presenting as sudden unexpected death in infancy. Early diagnosis through echocardiography, electrocardiography, and cardiac biopsy is critical for attempting therapeutic intervention.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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