Transesophageal atrial pacing distinguishes Mahaim fibers

AIM:To distinguish Mahaim fibers by transesophageal atrial pacing. METHODS: Fifty three patients were divided into Mahaim group (n=7) and Kent group (n=46). The interval of stimulus to QRS wave (S-R), accessory pathway progressive decrease conduction (ΔS-R), accessory pathway effective refractory period (ERP), and characteristics of tachycardia were examined by transesophageal atrial pacing. RESULTS: S-R in Mahaim group was longer than that in Kent group (71±20) msec vs. (28±14) msec (P<0.05), ΔS-R in Mahaim group and Kent group was, respectively, (103±28) msec and (12±11) msec (P<0.01). No statistical difference was observed in ERP between groups. CONCLUSION: Transesophageal atrial pacing could be used to distinguish Mahaim fibers.