Anthracyclines and the heart.

The anthracyclines are effective and widely used antineoplastic agents. They are used to treat many types of malignancy including acute lymphoblastic leukaemia.' Their introduction has considerably improved survival, especially in childhood cancers. Signs of cardiac toxicity may develop during, soon after or many years after a course of treatment. Early toxicity is dependent principally on the cumulative anthracycline dose. Typically the patient presents with left ventricular or congestive heart failure and with clinical features of congestive cardiomyopathy. Less often an arrhythmia is the first manifestation of toxicity. The major differential diagnoses are malignant pericarditis, cardiac injury from concomitant radiotherapy, and coincidental heart muscle or coronary artery disease. The two most widely used and studied anthracyclines are daunorubicin and its C-14 derivative, doxorubicin (adriamycin). They are glycoside antibiotics that owe their antineoplastic action to a complex effect that results in inhibition of nucleic acid synthesis by binding to both strands of the DNA helix, preventing the normal function of RNA and DNA polymerases.