Electrophysiologic study and surgical ablation of atrioventricular nodal reentrant tachycardia: report of one case.

A 12 years old boy with frequent episodes of palpitation was found, by the electrophysiologic study, to have an atrioventricular (AV) nodal tachycardia. Endocardial mapping during surgery revealed that the earliest retrograde atrial depolarization of the tachycardia occurred at the posterior part of Koch's triangle. Under normothermic cardiopulmonary bypass, perinodal dissection was performed above the tricuspid annulus at the coronary sinus region. The retrograde VA conduction disappeared. Post-surgery the antegrade conduction had a Mobitz type I block which had returned to normal after the fourth month follow-up.