Glycogen storage disease type II (Pompe's disease) is a rare inherited meta
bolic disorder, which often leads to infantile death from severe cardiomyop
athy. This case of sudden death illustrates the features of the cardiac fin
dings in the disorder, resulting from massive lysosomal accumulation of gly
cogen in the heart and other tissues. Pompe's disease should be considered
in cases of unexplained infantile cardiomyopathy.