Slow pathway ablation
AVNRT, arrhythmia, group-A
JUNCTIONAL RHYTHM, ARRHYTHMIA
The patients were randomly divided into two groups before ablation: 1-Group A (n = 30): treated with “conventional ablation” at the anatomic area of the slow pathway; 2-Group B (n = 32): ablation was done 2 mm higher in the septum (during fluoroscopy):In group-A, conventional anatomic slow pathway RF ablation was performed according to established techniques. In brief, a conventional 4-mm ablation catheter (Boston Scientific Stinger Ablation Catheter, D Curve 7 F) was positioned at the postero-septal (infero-septal) part of the tricuspid annulus until an A-V ratio of < 1 was recorded. The ablation catheter was kept at the ostium of the coronary sinus (CS) as visualized in the left anterior oblique view (mapping was not performed at the mid or anterior septum). When multi-component signals or low-amplitude potentials were obtained, RF current, 30 to 40 W aimed at a temperature of 55–60 °C, was delivered for up to 30 s until a junctional rhythm with 1:1 retrograde V-A conduction was observed. RF delivery was immediately stopped if V-A conduction was not seen. Once junctional rhythm with V-A conduction was recorded, energy delivery was continued for 30 s. Following RF ablation, arrhythmia induction with the use of Isuprel was performed. Successful ablation was defined as RF-induced junctional rhythm (conducted to the atria) and non-inducibility of AVNRT with programmed stimulation during Isuprel infusion.In group B, RF ablation was performed at 2 mm higher in the septum with the same techniques and catheters used for patients in Group-A.