Introduction
Atrioventricular (AV) nodal (AVN) reentrant tachycardia (AVNRT) is electrophysiologically classified into three forms according to the antegrade and retrograde limbs; slow-fast, fast-slow, and slow-slow forms1. Furthermore, several anatomical variants of the slow pathway (SP) such as rightward and leftward extensions2,3, superior SP (SSP) and inferolateral left atrial (LA) SP (ILA-SP), have been reported despite the unique fast pathway (FP)1,4,5. The earliest atrial activation (EAA) depends on the SP variant during the fast-slow AVNRT, which requires careful interpretation of the electrocardiogram to differentiate it from orthodromic reciprocating tachycardia (ORT) or atrial tachycardia (AT)6. We report a rare case of fast-slow AVNRTs with SP variants such as an SSP and ILA-SP.