Influence of Atrioventricular Nodal Reentrant Tachycardia Ablation on Right to Left Inter-atrial Conduction

BACKGROUND: Radiofrequency (RF) catheter ablation is the procedure of choice for the potential cure of atrioventricular nodal reentrant tachycardia (AVNRT) with high success rates. We hypothesed that as a result of the close proximity of Koch’s triangle and low inter-atrial septal fibers, the RF ablation applied at this region may result in prolongation of inter-atrial conduction time (IACT). METHODS: RF ablation of AVNRT was performed by conventional technique. IACT was measured before and 20 minutes after RF ablation during sinus rhythm. Number of ablations given and duration of ablation were noted. RESULTS: The study group was consisted of 48 patients (36 [75%] female, 12 [25%] male, mean age 43.4 ± 14. 5 years). RF ablation was successful in all patients. Mean RF time was 4. 0 ± 3. 3 minutes and mean number of RF was 11. 9 ± 9, 8. The mean IACT was 70.1 ± 9.0 ms before ablation and 84.9 ± 12.7 ms after ablation, which demonstrated a significant prolongation (p<0.001). The prolongation of IACT was very well correlated with the number of (r=0.897, p<0.001) and duration of RF (r=0.779; p<0.001). CONCLUSIONS: RF ablation of AVNRT results in prolongation of IACT. The degree of prolongation is associated with the duration and number of RF ablations given. The relationship between this conduction delay and late arrhythmogenesis need to be evaluated.