Mechanisms underlying atrioventricular nodal conduction and the reentrant circuit of atrioventricular nodal reentrant tachycardia using optical mapping

The findings of multiple nondiscrete AV nodal pathways and asymmetric transitional zone provide a biophysical basis for understanding normal and abnormal AV node electrophysiology. Unidirectional block occurring at the transitional zone transforms the nondiscrete pathways model into a classic dual pathways physiology for AVNRT.