Background Fast-slow atrioventricular nodal dual pathway, also known as atypical or rare dual atrioventricular node pathways, was uncommon, accounting for about 5 to 10 percent of atrioventricular nodal reentrant tachycardia.Its electrophysiological characteristics differ significantly from that of the slow-fast type of dual atrioventricular node reentrant tachycardia (AVNRT), its ECG has distinctive characteristics.In this paper, we summarized data of patients with definite diagnosis of the fast-slow type of atrioventricular nodal dual-path reentrant tachycardia, to explore ECG and tachycardia characteristics (electrophysiological characteristics) of the fast-slow AVNRT.