P974Electroanatomical mapping system in atrioventricular nodal reentrant tachycardia: anatomy of koch"s triangle and electrophysiological properties of the slow pathway
Authors: Ferretto S , Brunzin K , Pettenuzzo K , Di Pede F , Nangah Suh R 
Published: June 2020

The substrate for atrioventricular nodal reentrant tachycardia (AVNRT) is well established. The standard fluoroscopy and electrogram-guided slow pathway ablation has been widely confirmed as an efficacious technique. The use of non fluoroscopic electroanatomic mapping (NFEM) in AVNRT ablation allows a detailed analysis of the anatomy of Koch’s triangle and distribution of specific electrograms including His bundle electrogram. The analysis of Koch’s triangle dimension and anatomy is still poorly correlated to the electrophysiological properties of the slow pathway and to anthropomorphic characteristics of the patient. Moreover it is not clear if the use of the NFEM leads to a longer procedural time. 

AIM. The aim of our study was to research the presence of a correlation between Koch’s triangle dimension and anatomy and electrophysiological and anthropomorphic characteristics of the patient. We also evaluate if NFEM prolong total procedural time in ablations performed by "new generation" electrophysiologist (who learned AVNRT ablation in the NFEM era). 

METHODS. All slow-fast AVRNT ablations executed in 2019 in a single center by two "new generation" electrophysiologist were included. Electrophysiological characteristics of the slow pathway were collected. NavX™ EnSite Precision™ (Abbott, St. Paul, MN, USA) was used in non fluoroscopic procedures to anatomical reconstruction and to analyze Koch’s triangle; distance between effective ablation point and His potential (EA-H), effective ablation point and coronary sinus (EA-CS) and CS dimension were recorded (figure 1). Koch’s triangle area was calculated with Heron’s formula. Total procedural time was recorded to compare fluoroscopic and non fluoroscopic procedures. 

RESULTS. A total of 13 NavX™ guided zero-fluoroscopy ablation were included. The mean patients age was of 61.6 ± 12.7 years, 61.5% male, with a mean body mass index (BMI) of 26.7 ± 4.8. The mean Koch’s triangle area was of 142.8 ± 68.9 mm, the mean CS area was of 149.2 ± 77.0 mm. A positive correlation was found between EA-H distance and Koch’s triangle area (r= 0.513, p = 0.008) and EA-H distance and BMI (r = 0.683 p &lt; 0.001). Moreover a positive correlation resulted between AH jump (using programmed atrial stimulation) and EA-H distance (r = 0.783, p &lt; 0.001) and AH jump and Koch’s triangle area (r = 0.586, p &lt;0.001). Comparing NavX™ guided ablation and standard ablation in a similar group of patients (mean age of 57.7 ± 11.4 years, 45% male) no difference was found in total procedural time (97.1 ± 30.3 min with NavX vs 96.4 ± 28.1 min with fluoroscopy, p = 0.927). No complication occurred with both technique. 

CONCLUSION. In our study higher BMI were correlated with larger EA-H distance and larger Koch’s triangle area. Patients with longer AH Jump had larger EA-H distance and larger Koch’s triangle area. The use of NFEM showed to have advantages in terms of anatomical precision and fluoroscopy exposure without prolonging procedural time.

Abstract Figure 1