RESULTS
Procedural data
The average procedural time was 213 ± 60.9 min, and an average radiation
dose of 5862,5 mGy. Baseline pre-ablation HR was 100 ± 8.5 bpm, and HR
at the maximal tolerated dose of Isoproterenol before RFA was 170 ± 19
bpm. Following RFA, average HR was 74.5 ± 6.5 bpm (p=0.035), and maximal
HR with the same pre-ablation Isoproterenol doses was 132 ± 23 bpm
(p=0.036). Average HR during 24 h Holter pre was 93.16 ± 7.08 and post
RFA 76.66 ± 4.92 (p=0.031).
The area of earliest activation was located at the AR (11 or 12 O’clock
landmark from a caudal view of the SVC-RA junction) in all patients.
Extension of the RF lesions from the earliest region at the AR towards
its more septal region was needed in all the included patients and
produced a transitory HR increment before obtaining a significant and
sustained HR drop of around 25%. Notably, the activation recorded on
the septal aspect of the AR was later compared with the earliest site
from its lateral aspect. The mean distance between the RF applications
at the earliest region on the AR and the most septal ablated sites was 6
mm (Fig 4 d,e). The distance of the PN to the nearest RF application was
5mm (Fig 4 d,e).
Clinical outcomes
After a mean follow-up of 654 ± 417 days (Table 1), one patient required
reinitiating Ivabradine (at a lower dose than pre-ablation) for control
of symptoms, and one patient with a history of fibromyalgia complained
of mild exercise intolerance, despite no evidence of sinus node
dysfunction on post-ablation stress test and heart rhythm monitoring. No
patients reported heart palpitations or syncope during follow-up. The
average HR on 24-hour Holter post-ablation was 75 ± 5.6 bpm, the sinus
rate HR during stage 1 of a Bruce protocol exercise stress test was 120
± 10 bpm, and the chronotropic response was classified as normal by an
independent cardiologist in all the patients. (Table 1).