Abstract 15472: The Utility of Isoproterenol Testing in Pediatric Patients Following Atrioventricular Nodal Reentry Ablation

Intro: AVNRT is a common mechanism of SVT in pediatric patients. Catecholamines such as isoproterenol (ISO) are routinely given during post ablation (ABL) testing to confirm acute success. In light of its recent significant cost increase, the aim of our study was to determine if ISO is necessary in all pediatric patients after AVNRT ablation to ensure acute procedural success. Method: Retrospective study of patients Result: We identified 232 patients with AVNRT of whom 65 (28%) met the study criteria; 123 (53%) were excluded for requiring ISO to induce AVNRT prior to ABL, 23 (10%) for CHD, 12 (5%) with presumed AVNRT and 9 (4%) with an unsuccessful ABL. The average age was 14.4 yrs (±3.5) and 54% were female. All patients received anesthesia, 40/65 were intubated (62%). Evidence of slow pathway conduction (Spath) (AH jump with atrial extrastimulus testing, presence of AV nodal echo beats or PR>RR) was seen in 35/65 patients (54%). Patients were divided into 2 groups: group 1 (n= 57, 88%) consisted of patients without inducible TACHY post ABL while receiving ISO, group 2 (n = 8, 12%) of patients in whom TACHY was inducible with ISO thus required further ABL. There was no difference between the groups with regards to sex, age, intubation status, prior use of antiarrhythmic meds, or in the incidence of Spath (31/57, 54% vs. 4/8, 50%, p=1). Four of the 8 patients in group 2 with no evidence of Spath had inducible TACHY with ISO. Conclusion: We found that 12% of pediatric patients who did not require ISO to induce AVNRT prior to ABL had inducible TACHY only with ISO after AVNRT ABL. Presence of dual AV nodal physiology after ABL lesions did not predict inducibility of AVNRT on ISO, and 50% of the patients with no evidence of slow pathway conduction by conventional testing had inducible AVNRT with ISO. ISO testing is useful in all pediatric patients to test for inducibility following catheter ablation of AVNRT.