High-density mapping with fragmentation analysis in patients with reentrant atrial tachycardias (MAP-FLURHY study).

PURPOSE

Reentrant atrial tachycardias (ATs) use areas of slow conduction that can be visualized as fragmented electrograms. We aimed to test an ablation strategy based on the identification and ablation of spots with fragmented electrograms in reentrant ATs, using Rhythmia navigation system.

METHODS

All consecutive patients from June 2016 to June 2019 were included. The IntellaMap ORION Catheter was used to detect sites with fragmentation, arbitrarily defined as fragmented electrograms > 70 ms. Entrainment was used to check if these areas belonged to the AT circuit. Ablation targeted the longest fragmented electrogram within the circuit: focal ablation for microreentries and lines for macroreentries. Ablation success was defined from each AT as conversion to sinus rhythm or another AT.

RESULTS

Twenty-seven consecutive patients with 44 mappable ATs were included. All ATs showed sites with fragmented electrograms (104 sites; 2.4 sites per AT); 43/44 ATs had fragmented electrograms within the circuit, which were the target of ablation. Ablation success: 34/36 ATs (94%); success could not be assessed in 8 circuits, in 6 due to mechanical conversion to sinus rhythm at the target fragmented site. Fragmented electrograms within the AT circuits were longer than electrograms outside the circuits (110 ± 30 vs 90 ± 15 ms, p < 0.001). A fragmentation duration > 100 ms/ > 40% of the AT cycle length predicted to be a successful site for ablation with 72.3%/73.8% specificity, respectively. Sixty-two percent of the patients were free from atrial arrhythmias at 1 year.

CONCLUSIONS

Most ATs had detectable fragmented electrograms within the circuit, which could be the target of ablation with high efficacy.