Long RP Tachycardia and Short RP Tachycardia: Is the Nodoventricular Pathway a Culprit or an Innocent Bystander?

ABSTRACT We encountered a single case in which a transition between orthodromic reciprocating tachycardia with a concealed nodoventricular pathway and atrioventricular nodal reentrant tachycardia with a bystander nodoventricular pathway was observed.