Radiofrequency ablation (RFA) of the atrioventricular nodal reentrant tachycardia (AVNRT) is associated with the risk of complete atrioventricular (AV) block. This risk is majored by some anatomic conditions and remains a serious complication in young patients. Herein, we would like to report 2 cases of 3D mapping system use to guide RF ablation of AVNRT.

This is a case of a 57-year-old man with a long medical history of atrial fibrillation (AF). He presented with palpitation and dyspnea. Physical examination was normal. On ECG, supraventricular tachycardia (SVT) with a heart rate of 144 beats per minute was noted. RFA was indicated because of the recurrence of this symptomatic tachycardia. CARTO 3D system mapping was used as the patient has a medical history of multiple ablated AF. RF delivery below the Coronary sinus (CS) ostium showed an accelerated junctional rhythm. No SVT was reproducible at the end of the procedure.

A 50-year-old patient reported chest pain and dyspnea related to SVT. Physical examination and tranthoracic echocardiography were unremarkable. On ECG, a supraventricular tachycardia with long RP’ with ST depression was noted. Blood tests showed troponin elevation. Coronary angiography was normal. This patient had a long medical history of tachycardia that often starts and ends suddenly, not improved by beta-blockers treatment. RFA was indicated. RHYTHMIA Mapping system was used. The EP study reproduced the clinical tachycardia, which was a slow-slow AVNRT. RF delivery for 90minutes below the CS ostium and 12mm under the His bundle eliminated completely the slow pathway.

The 3D mapping systems is an interesting tool for AVRNT RF ablation. It is correlated with lower radiation exposure and shorter procedure time. It may offer more security in young patient and those with a short distance between His bundle and CS ostium.