Cryoablation for Atrioventricular Nodal Reentrant Tachycardia in Young Patients: Predictors of Recurrence

Abstract

BACKGROUND Recurrence rates of AVNRT after cryoablation continue to remain high despite excellent initial success rates. Our objective was to evaluate the clinical outcomes of cryoablation for AVNRT with the 4 mm and 6 mm tip cryoablation catheters in a young population and to elicit predictors of arrhythmia recurrence. METHODS We retrospectively reviewed all patients who underwent cryoablation for AVNRT at the UCSF/Stanford Pediatric Arrhythmia Center from 1/04-2/07. RESULTS 154 patients (age 13.7 years (3.2 – 24.4)) underwent cryoablation for AVNRT. 144 patients had inducible AVNRT (123 sustained and 21 nonsustained) and 10 had presumed AVNRT. Initial success was achieved in 95% (146/154), with no difference between the 4 mm (93%) and 6 mm (98%) cryoablation catheter tips (p=0.15). There was no permanent atrioventricular (AV) block. Transient 3rd degree AV block occurred in 9 patients (6%), with no difference between the 4 mm (4%) and 6 mm (9%) (p=0.13). AVNRT recurrence was documented in 14% in a median time of 2.5 months (0.25–20). Recurrences were lower with the 6 mm (9%) versus the 4 mm (18%), but this did not reach statistical significance (p=0.16). With univariate analysis, a longer fluoroscopy time was the only significant factor associated with recurrence. Multivariate analysis failed to identify any significant predictor of AVNRT recurrence. CONCLUSION Outcomes of cryoablation for AVNRT continue to be good without the complication of AV block. We could not identify any specific parameter associated with AVNRT recurrence. Further improvements in cryoablation technique will be necessary to reduce recurrences.

Long-Term Follow-Up After Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Children

“…Although no difference was found about ablation end point, that is, complete SP ablation versus SP modulation, 6,22 the choice of ablation energy has been proven to influence long-term efficacy: cryoenergy was associated with a higher AVNRT recurrence rate, but the procedural risk of permanent AV block was lower 6,23,24 In accordance with previous reports, 22,25,26 we did not find any difference in long-term recurrence rates between patients with SP ablation versus SP modulation at the end of the procedure. Because the number of patients with AVNRT recurrence was low (n=22), any analysis on factors for recurrence has low statistical power.…”

Prevention and Treatment of Thrombosis in Pediatric and Congenital Heart Disease

“…Several studies in pediatric patients who have had catheter cryoablation have been reported with no thromboembolic complications. [546][547][548][549] Compared with RFCA, catheter cryoablation appears to be less thrombogenic. An in vitro study demonstrated significant damage to blood cells and platelets with RFCA compared with catheter cryoablation.…”

Comparison of Endocardial and Epicardial Lesion Size Following Large-Tip and Extra-Large-Tip Transcatheter Cryoablation

“…18 Furthermore, a recent study showed that the AVNRT recurrence rate was higher with a 4-mm tip cryoablation catheter (18%) than with a 6-mm tip cryoablation catheter (9%). 19 Thus, in the present study we compared the effect of cryoablation catheter size and length on acute and chronic left ventricular lesion sizes. We evaluated cryocatheters of 2 different sizes in porcine and canine endocardial and epicardial ablation models, and examined the acute and chronic effects of cryothermal ablation on ventricular tissue.…”