Diagnosis of Chloroquine Cardiomyopathy by Endomyocardial Biopsy

CHLOROQUINE and hydroxychloroquine are antimalarial agents that are often used in the treatment of collagen vascular diseases. However, both drugs can cause a toxic skeletal-muscle myopathy, the histology of which has been carefully described.1 2 3 4 5 6 7 8 9 Chloroquine toxicity results in cardiomyopathy in animals, but documentation of cardiac involvement in humans has been limited to evidence of conduction abnormalities in one patient, congestive heart failure in another patient, and the finding of vacuolar degeneration of cardiac muscle during two autopsies.1 , 4 5 6 7 8 This report describes the light and electron microscopical findings in chloroquine and hydroxychloroquine myocardial toxicity in two patients, as revealed by endomyocardial biopsy. . . .