Cardiac involvement in juvenile amaurotic idiocy--a specific heart muscle disorder. Histological findings in 13 autopsied patients.

Juvenile amaurotic idiocy (JAI) is a rare disorder of autosomal recessive inheritance. It belongs to the so called ceroid lipofuscinoses and the central nervous system is the largest organ. Only very few reports refer to the accumulation of lipopigment in the heart of JAI patients. This study describes the morphology of the heart from all 13 patients with JAI in Denmark who died within a seven year period; electrocardiographic findings are related to structural changes. All compartments of the heart were involved, including the conduction system. Not only very substantial deposition of lipopigment was found in the myocytes, but we have also observed striking amounts of calcium and cholesterol compounds indicating a restrictive type of heart muscle disorder. These structural changes are uniform from case to case. Because of the nature of the disease only rather poor information of the cardiac state is available in JAI patients. 11 patients showed some cardiac enlargement. In 6 patients abnormal P-waves were recorded in the ECG suggesting increased atrial and ventricular diastolic pressure. 2 patients had bradycardia, probably due to sinus node involvement, and one patient developed complete right bundle branch block. However, in the 4 patients in whom the cardiac conduction system could be examined histologically no evidence of disturbance of cardiac impulse formation and conduction was seen in the few standard ECG strips available in spite of extensive deposition of abnormal material throughout the conduction system. There seems to be a discrepancy between the relatively minor functional disturbances observed and the heavy morphological changes of the entire heart. This aspect, however, may well be altered by an intensified clinical observation and examination of JAI patients.