Sustained "slow-fast" and "fast-slow" AV nodal re-entrant tachycardia in a patient with recurrent supraventricular tachycardia.

A case is presented of a 21-year-old woman with recurrent paroxysmal supraventricular tachycardia. Electrophysiologic study demonstrated the presence of both antegrade and retrograde dual AV nodal conduction pathways and both conventional slow-fast and atypical fast-slow forms of the AV nodal re-entrant tachycardia could be induced. Both tachycardias were successfully suppressed with a combination of digoxin and verapamil.