The use of electroanatomic mapping (EA) during ablation allows the exposure of both patients and EP staff to fluoroscopy (FL) to be reduced. However, for some EP techniques, such as aortic retro-navigation or trans-septal catheterization (for left heart navigation) FL is often required. Atrio-ventricular nodal reentrant tachycardia (AVNRT) is one of the most frequent supraventricular tachycardia (SVT) in young people.
Our aims were to assess the safety and efficacy of AVNRT ablation procedures in which the Carto3™ and EnSiteTMNavX™ EA systems were used and to identify some key measures to avoid any FL use during procedures.
From June 2015 to October 2016, 60 consecutive patients underwent ablation for SVT in our EP lab. In these patients, 20 AVNRT procedures (19 patients; 1 redo) were performed and were included in the present study (8 males, mean age 47+/-13.3 years). In all patients, 2 diagnostic catheters and a standard 4mm non-irrigated ablation catheter were used.
All patients successfully underwent ablation (1 patient underwent a "redo" procedure after 7 months). The Carto3™ EA system was used in 10 cases and the EnSite™ NavX™ EA was used in the remaining 10 (the study was not designed to compare the EA systems). No major procedural complications occurred. In one patient a 1st degree AV block was recorded (followed up by means of implantable loop recorder: Reveal LINQ™ Medtronic). At 3-month follow-up examination, all patients were free from AVNRT (and symptoms).The mean procedure time was 111.2 min ± 127.8 min; the mean EP study time was 24 ± 17 min. The mean fast anatomical mapping (FAM) time was 13 ± 4.4 min. The mean radiofrequency delivery time was 116 ± 122.7 sec. The FL time was 0 (Dose area product = 0 cGy*cm2).
The following steps enabled the use of FL to be safely and effectively avoided:
careful femoral vein cannulation slightly above the great saphenous/femoral vein junction (to allow straight femoral-iliac vein navigation); "His-based" FAM reconstruction; the mandatory use of the His mapping catheter to match the real time catheter position with the His EA tag and the display and measurement of Kock triangle details.
AVNRT ablation may be safely and effectively performed by means of a real zero FL procedure, regardless of the EA system used. Some methodological steps may help to reach this target. These findings may be applicable to all right heart EP ablation procedures.