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.