Hyperkalemia-induced bundle branch block and complete heart block.

Hyperkalemia was associated with complete heart block in one patient that resolved by first showing right anterior hemiblock). Then the right bundle branch block resolved, leaving the marked left axis deviation that was present before the hyperkalemic episode. Another patient with hyperkalemia had right bundle branch block with marked left axis deviation, both of which disappeared with correction of the hyperkalemia. These findings suggest that hyperkalemia can depress conduction in the His-Purkinje system and raise the possibility that hyperkalemia may induce complete heart block distal to the atrioventricular junction.