215 Is it necessary to indicate another electrophysiological study in patients previously studied for a preexcitation syndrome

Accessory pathway (AP) refractory period (RP) increases from the youth to the elderly. The large indications of AP ablation have changed the natural follow-up. The purpose of the study was to report the clinical and electrophysiological data of pts with a Wolff-Parkinson White syndrome (WPW), studied within 1 to 20 years of one another to evaluate the changes of these data. Methods 2 baseline EPS were performed within 1 to 20 years (y) of one another (mean 9 y ± 4) in 61 pts, 37 males and 24 females, aged initially from 10 to 67 y (30 ± 14), with a patent WPW. First electrophysiological study (EPS) was indicated for syncope (n = 6), atrioventricular reentrant tachycardias (AVRT) (n = 34), atrial fibrillation (AF) (n = 5) or for asymptomatic preexcitation (n = 16). The protocol was similar: the higher rate conducted through AP was measured and programmed atrial stimulation with 1 and 2 ES performed in control state (CS) and after isoproterenol. Results At 2 nd study, among pts studied for syncope at study 1, 1 has still syncope, 2 have AVRT, 1 has rapid AF, and 2 are asymptomatic. Among pts with AVRT at study 1, 25 have AVRT, 7 are asymptomatic and 2 have AF. Among pts with AF, 4 have still AF and 1 is asymptomatic. Among asymptomatic pts 3 have a spontaneous malignant form, 7 remain asymptomatic, 3 have AVRT, 1 has syncope and 1 has AF. All AVRT or AF occurred in pts with inducible AVRT or AF at EPS 1. The higher rate conducted by AP was significantly lower in CS and after isoproterenol at study 2 (157 ± 95 b/min, 193 ± 113) than at study 1 (199 ± 65, 257 ± 65). AP has lost anterograde conduction properties in 17 pts aged from 17 to 67 years (47 ± 15); all of them but one had initially 1/1 conduction through AP 170/min. However 8 of them had still AVRT. Among pts with initially rapid conduction through AP (250/min), all but one have a rapid conduction at EPS 2; 3 of them which were asymptomatic developed rapid AF. Conclusions The study confirms that a benign form of WPW without inducible AVRT or AF remains benign. Pts with AVRT and AP and long refractory period become asymptomatic in 20% of cases. Pts with inducible rapid AF remain at high risk of events in most cases.