Preexcitation syndrome (PS) is a potential cause of sudden cardiac death; its prognostic assessment is a major issue. The aim was to assess the contribution of esophageal electrophysiological study (EPS) compared to intracardiac EPS for the prognostic evaluation in patients with PS.

We conducted a prospective single-centre study between November 1^st, 2008 and December 1^st, 2014, in patients who underwent both esophageal and intracardiac EPS for a PS. Accessory pathway effective refractory period (APERP) and induction of sustained supraventricular tachyarrhythmias (SVT) were noted for both methods.

69 patients were included. 45 (65%) were males and mean age was 36±16 years. There were no significant differences in the induction of SVT between both methods. APERPs were significantly shorter at esophageal EPS compared to intracardiac EPS in control state (>40ms) in 51% of patients, but APERPs did not decrease significantly after isoproterenol: in these patients with shorter APERP at esophageal EPS, age and gender was similar to other patients; APERPs in basal state were shorter than in patients with similar APERPs at both studies (255±43 vs 281±61)(p0.032), but APERPs after isoproterenol were similar (226±33 vs 231±45)(0.55); the shortening of APERP after infusion of isoproterenol was significantly less than in patients with similar APERPs at esophageal and intracardiac EPS (30±31ms vs 49±45ms)(p<0.05). The sensitivity of esophageal EPS in prognostic assessment was 88% in control state, 100% during isoproterenol infusion. The area under ROC curve of transesophageal EPS in prognostic assessment based on APERP measurement was 0.74.

Esophageal EPS was a reliable and sensitive method of prognostic assessment in patients with PS. APERP was shorter in 51% of patients but did not decrease significantly after isoproterenol at esophageal EPS compared to intracardiac EPS, indicating esophageal EPS-related stress.