Endomyocardial biopsy in children with cardiac hypertrophy.

Transvascular right ventricular endomyocardial biopsy was carried out on three boys with severe hypertrophic hearts. There were no complications, but technically the use of the thin-walled, long introducer-sheath (available for the child-size bioptome) was rather troublesome because of its tendency to kink. Light-microscopy was helpful in diagnosing hypertrophic cardiomyopathy and possible endocardial fibroelastosis in two cases and in excluding eosinophilic myocarditis in the third case. Concealed storage disease (amyloidosis) was excluded and therefore the use of experimental cytotoxic therapy--with potential adverse effects--was avoided. A more stable sheath material ought to be developed to prevent untoward incidents during biopsy procedures in children.