Factors Associated with Recurrence of Accessory Pathway Conduction After Radiofrequency Catheter Ablation

TWIDALE, N., ETAL.: Factors Associated with Recurrence of Accessory Pathway Conduction After Radiofrequency Catheter Ablation. Catheter ablation of 215 accessory pathways (APs} using radio/requency current (HFJ was attempted in 204 consecutive patients. Two hundred tweJve of the 215 (99%) APswere success/uJiy ablated. After a minimum follow-up period of 1 month (mean 8.5 ± 5.4 months), AP conduction had relumed in 17 patients (8%). Recurrence of AP conduction was manifest by atrioventricu Jar (AVj reentrant tachycardia in six patients, palpitations suggestive of AV reentrant tachycardia in five patients, ventricular preexcitation on electrocardiogram in five patients, and inducible AV reentrant tachycardia during a follow-up eJectrophysioJogical study in one asymptomatic patient. AP conduction returned as eariy as 12 hours and as late as 4.7 months, but was evident within 2 months of abiation in 15 of 17 (88%} patients. AP conduction recurred in 12%-14% of anteroseptal, right free-wall, and posteroseptai APs, but only 5%o/Ie/t/ree-ivaJI APs(P< O.OIJ. Retrogradeonly conducting APs (concealed APsJ had recurrence o/AP conduction more/requentJy (16%) than APs that exhibited antegrade conduction (5.5%; P < 0.01). Failure to record AP potentials from the ablation eJectrode, refiecting poor AP localization, was a strong predictor for recurrence of AP conduction. AP conduction returned in 1.9% of 48 APs when AP potenfiaJs were not recorded, compared to 5% of 164 APs where AP potentials were recorded from the abJation eJectrode (P < 0.01). The time to block of AP conduction/rom the onset of RF current appJication was Jonger in APs with recurrence o/conduction (4,9 ± 6.1 sec vs 2.9 ± 3.4 sec; P < 0.02}. Recurrence of AP conduction was more frequent when the stability of the ablation electrode was poor (12% of 41 APs vs 7% of 171 APs with stable electrode placement), and when the AP had multiple components (11% of 36 APs ablated at multiple sites vs 7% of 176 APs where AP was abJated at a single site), but these were not statistically signi/icant. Ail 17 patients with recurrence of AP conduction underwent a second successful abJation. Jn conclusion, the overaJI incidence o/recurrence of AP conduction is low, but is higher for right/ree-wall and septal APs, concealed APs, and probably relates to poor AP localization. {PACE, Vol. 14, November, Part U 1991)