A rare cause of 2:1 atrioventricular block: carbamazepine.

We report a case of carbamazepine-induced 2:1 atrioventricular (AV) block. A 56-year-old man was admitted to our emergency department for recurrent attacks of dizziness and syncope. His serum carbamazepine level was within therapeutic range, and his electrocardiogram revealed 2:1 AV block. After withdrawal of carbamazepine therapy, the arrhythmia completely resolved. This report suggests that carbamazepine-induced AV block can occur even in therapeutic serum concentrations and that it can be reversible.