Catheter ablation (CA) with the use of fluoroscopy became a gold standard of treatment for recurring regular supraventricular tachycardias (SVT) and substrates, including atrioventricular nodal re-entrant tachycardia, accessory pathways, atrial flutter, and atrial tachycardia. The development of three-dimensional electro-anatomic mapping systems and invasive electrophysiology enabled physicians to perform CA in various SVT types with the complete elimination of fluoroscopy; this is called the no X-ray (NXR) method. This method of catheter navigation and mapping has been evaluated in various non-randomised and small randomised trials with a limited number of patients; however, there are still limited data on performing NXR CA in SVT.
Beginning in 2012, the prospective ELEKTRO registry recorded >1,500 consecutive patients (including paediatric cases) referred for NXR CA of SVT as a standard approach. They were compared to >700 patients who underwent classical mapping and navigation with the use of fluoroscopy. Procedures were performed by experts and fellows in CA. In all cases, the simplified 2-catheter protocol from femoral access was used (the left-sided accessory pathways retrograde approach was preferred if no patent foramen ovale was found) with a 15-minute observation period after successful application. The only contraindications for the NXR approach were in cases of cardiac electronic implanted devices and planned pulmonary vein isolation for atrial fibrillation.
There was a significant decrease of procedural time in the NXR group compared to the X-ray approach. In the NXR group, <9% of procedures required conversion to the X-ray approach, with a significant reduction in fluoroscopy time compared to the X-ray approach; the mean fluoroscopy in NXR group was <1 minute. There were no major differences in acute success or complication rates in the NXR group compared to the traditional X-ray approach. Moreover, after incorporating the NXR approach in fellow training there was a minimal, but significant, increase in procedural time between the last quartile and the first quartile in the NXR group but with significant reduction of fluoroscopy time. No major complications were reported.
These data show that in a wide range of patients with SVT, NXR is safe and effective. NXR may become the gold standard for CA treatment and training for a new generation of CA experts in the near future, which may significantly reduce radiation exposure for patients as well as for physicians and allied professionals.
