The HAV pattern in pediatric patients with atrioventricular node reentrant tachycardia.

OBJECTIVES:The purpose of this study is to assess the prevalence of a His-Atrial-Ventricular (HAV) pattern, i.e. the atrial electrogram following the His bundle -HB- electrogram and preceding the ventricular one, on the catheter placed in the His position in pediatric patients during typical atrioventricular node reentry (AVNRT). MATERIALS AND METHODS:The pediatric electrophysiology databases of two separate institutions were queried for patients with a diagnosis of AVNRT. Demographic, clinical data and the electrophysiology study (EPS) information were assessed. RESULTS:Thirty-nine consecutive patients were included. Twenty-five were female. The average age at the time of the EPS was 12 ± 3.7 years. Induction was achieved with atrial pacing in 23, with a single atrial extra stimulus in 8 and with dual atrial extra stimuli in 8. Isoproterenol was needed to induce tachycardia in 21. Tachycardia cycle length averaged 320 ± 50 ms. An HAV pattern was present in 35 (74%) of the patients, and in 100% of the patients younger than 8. CONCLUSIONS:An HAV pattern on the catheter placed in the His position, is common in pediatric patients with AVNRT, occurring in up to 74% of the patients in this population, being more common in younger patients.