ABSTRACT
Introduction. Unstable reentrant atrial tachycardias (ATs)
(i.e. those with frequent circuit modification or conversion to atrial
fibrillation) are challenging to ablate. We have tested a strategy to
achieve arrhythmia stabilization into mappable stable ATs based on the
detection and ablation of rotors.
Methods and Results . From May 2017 to December 2019, 97
consecutive patients with reentrant ATs were ablated. Of these, 18
(18.6%) presented unstable circuits and were included. Mapping was
performed using conventional high-density mapping catheters (IntellaMap
ORION, PentaRay NAV or Advisor HD Grid). Rotors were subjectively
identified as fractionated continuous (or quasi-continuous) electrograms
on 1-2 adjacent bipoles of the mapping catheter, without dedicated
software. 13 patients (72%) had detectable rotors (median 2 [1–3]
rotors per patient); focal ablation achieved conversion into stable AT
or sinus rhythm in 12 (92%). In the other 6 patients, sites with
spatiotemporal dispersion (i.e. all the cycle length comprised within
the mapping catheter) plus non-continuous fractionation on single
bipoles were targeted. 17 sites with spatiotemporal dispersion were
detected and focally ablated. Globally, and excluding 1 patient with
spontaneous AT stabilization, ablation success to stabilize the AT was
achieved in 16/17 patients (94.1%). One-year freedom from atrial
arrhythmias was similar between patients with unstable and stable ATs
(66.7% Vs 65.8%, p=0.946).
Conclusion . Most unstable reentrant ATs show detectable rotors,
identified as sites with single-bipole fractionated quasi-continuous
signals, or spatiotemporal dispersion plus non-continuous fractionation.
Ablation of these sites is highly effective to stabilize the AT or
convert it into sinus rhythm.