Catheter excursion, inter-lesion distance tied to arrhythmia recurrence after ablation

The spatial instability of the ablation catheter, as well as decreased lesion sequentiality, predict the recurrence of arrhythmia in patients undergoing radiofrequency ablation for paroxysmal atrial fibrillation (AF), a new study has shown.

Researchers enrolled 100 consecutive patients (mean age, 62±11 years; 66 percent male), in whom the spatial position of the ablation catheter was assessed when radiofrequency was being applied at a frequency 60 Hz. The primary study outcome was freedom from atrial arrhythmia for at least 30 seconds after one ablation procedure. Fourteen participants were under continuous implantable monitoring.

There was a total of 14,703 ablation lesions assessed, corresponding to 1,044±525 position data points per lesion. Over 15 million position data points were analysed in total. Kaplan-Meier analysis estimated an 86-percent arrhythmia-free survival rate at the 1-year follow-up.

Patients who experienced recurrence also showed significantly greater mean (1.08±0.13 vs 0.98±0.17 mm; p=0.01) and maximal (3.07±0.38 vs 2.80±0.40 mm; p=0.03) catheter excursion. The same was true for the percentage of lesions with inter-lesion distance >6 mm (53±9 percent vs 46±8 percent; p<0.001).

No such differences were reported for other ablation parameters, such as radiofrequency time, lesion duration, impedance decline and the average power delivered.

Logistic regression analysis further confirmed that having more lesions with >6-mm inter-lesion distance (odds ratio [OR], 1.12, 95 percent confidence interval [CI], 1.04–1.22) was a significant risk factor for recurrence, as was greater excursion (mean: OR, 28.94, 95 percent CI, 1.02–819.17; max: OR, 5.15, 95 percent CI, 1.21–21.90).