3D Mapping Versus Conventional Ablation in AVNRT

Atrioventricular nodal re-entrant tachycardia (AVNRT) is one of the most common forms of paroxysmal supraventricular tachycardia. Catheter ablation targeting the slow AV nodal pathway is considered definitive therapy with high procedural success rates.

Conventional fluoroscopy-guided ablation mainly relies on anatomical landmarks and intracardiac electrogram interpretation. However, fluoroscopy exposure remains an important concern for both patients and operators. Three-dimensional electroanatomical mapping systems allow detailed reconstruction of the triangle of Koch and facilitate substrate-guided ablation using voltage, activation, and fractionated electrogram mapping techniques. These systems may reduce fluoroscopy exposure and improve procedural precision and efficacy.

This prospective randomized two-arm interventional study was conducted at the Cardiology Department, Kafr El-Sheikh University Hospital, between December 2023 and November 2025. A total of 108 consecutive patients with symptomatic supraventricular tachycardia suggestive of AVNRT were screened for eligibility. Following assessment according to predefined inclusion and exclusion criteria, 80 eligible patients with electrophysiologically confirmed typical AVNRT were enrolled and randomized in a 1:1 ratio to either conventional fluoroscopy-guided slow pathway ablation (Conventional group, n = 40) or three-dimensional electroanatomical mapping-guided slow pathway ablation (3D group, n = 40).

During the study period, post-randomization dropouts and exclusions occurred in both groups. Consequently, the final analysis included 38 patients in the conventional ablation group and 36 patients in the 3D mapping-guided ablation group.

In the conventional arm, ablation was performed using standard fluoroscopic anatomical landmarks and intracardiac electrogram criteria within the triangle of Koch. In the 3D mapping arm, high-density electroanatomical mapping using CARTO or EnSite X systems was performed with integrated voltage, activation, and fractionated electrogram mapping to identify optimal ablation targets.

Primary outcomes included fluoroscopy time, fluoroscopy dose, complete slow pathway elimination, and procedural success defined as non-inducibility of sustained AVNRT after ablation. Secondary outcomes included total procedure duration, number and duration of radiofrequency applications, complications, recurrence during follow-up, hospital stay duration, need for redo ablation, and predictors of complete slow pathway elimination.

Inclusion criteria

• Sustained symptomatic supraventricular tachycardia with surface ECG features highly suggestive of atrioventricular nodal re-entrant tachycardia (AVNRT).
• Electrophysiologically confirmed typical (slow-fast) AVNRT during the index electrophysiology study.
• Ability to provide written informed consent.

Exclusion criteria

• Coexisting arrhythmia requiring concurrent catheter ablation during the same procedure.
• Non-inducible AVNRT at the time of electrophysiological study.
• Antiarrhythmic drug use within 48 hours before the procedure or ongoing amiodarone therapy.
• Hemodynamic instability precluding safe catheter manipulation.
• Pregnancy.