A new approach for catheter ablation of atrial tachycardia following atrial fibrillation ablation.

OBJECTIVE

The origin and mechanisms of focal and macro-re-entrant atrial tachycardia occurring after ablation of paroxysmal or persistent atrial fibrillation are difficult to determine and are often the cause of distress for both patients and electrophysiologists. The purpose of this study was to describe a novel practical approach which would be helpful in planning the treatment of atrial tachycardia in patients who had received prior atrial fibrillation ablation. We used an algorithm which aims to facilitate mapping and ablation strategies, using both conventional electrophysiological tools and a three-dimensional electroanatomic approach.

METHODS

We investigated a series of 40 patients with atrial tachycardia who had undergone a prior ablation procedure for paroxysmal or persistent atrial fibrillation with a step-wise approach. This approach consisted of four steps: the use of a decapolar catheter to assess the coronary sinus and an entrainment map to evaluate the cavotricuspid isthmus (CTI). If the CTI was not involved, we used a 20-pole dual-loop circular mapping catheter, AFocusII DL, to map the left atrium chamber rapidly during the rhythm of interest. We identified the target entrainment at the putative channels and performed catheter ablation at the critical isthmus of these macrocircuits until the restoration of sinus rhythm.

RESULTS

Seventy-five atrial tachycardias were identified in 40 consecutive patients (1.9 ± 1.6 per patient). In 48, the mechanism was macro-re-entry, and the remaining 27 were focal. During 18 months of follow-up, the treated arrhythmia recurred in only three patients, whereas in another four patients, a different atrial tachycardia was observed. The remaining 33 patients maintained sinus rhythm.

CONCLUSION

The increased acquisition speed by AFocusII DL facilitated the reconstruction of the geometric chamber, and the generation of an isochronal activation map reduced processing time and fluoroscopy time per patient, together with the radiation exposure and patient radiation dose. A novel algorithm combining both conventional electrophysiology and a three-dimensional electroanatomic approach for rapid diagnosis, accurate mapping and ablation of iatrogenic atrial tachycardias showed high reproducibility and a satisfactory overall success rate.