Delayed cardiotoxicity in chronic lithium poisoning: discrepancy between serum lithium concentrations and clinical status.

Chronic lithium poisoning is characteristically associated with greater toxicity than acute ingestion. Neurotoxic features may occur within several hours, whereas major cardiovascular effects are typically not seen until later. This report describes profound bradycardia as a late consequence of chronic lithium poisoning, and reminds us to consider the possibility of delayed toxic effects, even in situations where serum lithium concentrations appear to be declining.