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Cryoablation versus Radiofrequency Ablation of the Atrioventricular Node in Patients with His-bundle Pacing
EP Europace Journal
Abstract
Atrioventricular node (AVN) ablation in the setting of His bundle pacing (HBP) may be challenging due to risk of compromising the function of the His lead. Cryoablation (CRYO) may offer theoretical advantages over conventional radiofrequency ablation (RFA), due to absence of shunting of current to the His lead, more discrete lesions, and potential reversibility in case of transient elevation of capture thresholds. However, CRYO has never been tested for AVN ablation in this setting.
To compare procedural characteristics and outcome of CRYO compared to RFA for AVN ablation in patients with HBP.
Thirty-five patients (age 76 ± 8 yrs, 23% male) with HBP underwent AVN ablation for an "ablate and pace" indication. CRYO was performed in the first 22 pts and RFA in the following 13 pts. Procedure and fluoroscopy times, change in His threshold and success rates were compared between groups.
The acute procedural success rate was 100% for both strategies without any major complications. There were no significant differences in procedure characteristics and outcome between CRYO and RFA, except for significantly shorter application times with RFA and a trend to more frequent reconduction and requirement for a redo procedure with CRYO (see table). All recurrences occurred within one month after ablation.
CRYO does not seem to offer any advantage over RFA for AVN ablation in patients with HBP, and does not avoid rise of His capture thresholds. Moreover, the recurrence rate may be higher with CRYO leading to more redo procedures.
Table Interquartile range is shown in square brackets. *one loss of capture.Parameter CRYO (22 pts) RFA (13 pts) P-value Total procedure time (min) 50 [38 - 63] 40 [33 - 53] 0.257 Fluoroscopy time (min) 5.0 [2.2 - 5.4] 3.5 [1.9 - 9.0] 0.578 Expo Rx (mcGy.cm2) 237 [110 - 525] 139 [65 - 721] 0.468 Number of applications (n) 6 [3 - 11] 4 [1 - 15] 0.371 Total application time (min) 17 [9 - 29] 3 [1 - 9] 0.001 His threshold pre-ablation (V) 1.63 [0.75 - 3.44] 0.75 [0.53 - 1.63] 0.180 His threshold post-ablation (V) 1.88 [0.75 - 3.81]* 1.25 [0.63 - 3.50] 0.389 His threshold change (V) 0.00 [0.00 - 0.31]* 0.00 [0.00 - 0.75] 0.933 His threshold rise ≥1 volt (n) 4 (18%)* 3 (23%) 0.726 Acute procedural success (n) 22 (100%) 13 (100%) 1.000 AV reconduction during follow-up (n) 5 (23%) 1 (8%) 0.254 AV reconduction needing redo procedure (n) 3 (14%) 0 0.146
