Post-ablation prolongation of atrioventricular nodal refractory period is correlated with long-term success of cryoablation for atrioventricular nodal reentrant tachycardia in the case of the persistence of a residual jump.

PURPOSE

A residual slow pathway after successful cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) is correlated with a higher recurrence rate. We described determinants of recurrence in subjects with a residual jump.

METHODS

We analyzed the data of subjects with acute successful slow pathway cryoablation for AVNRT using a 6-mm-tip cryocatheter. Success was defined as AVNRT non-inducibility. Patients with no baseline elicitable jump, no inducible AVNRT, and transient first atrioventricular (AV) block at the last site were excluded.

RESULTS

From 371 patients who underwent cryoablation from May 2002 to March 2011, 303 fulfilled the entry criteria (mean age, 41 ± 16; 222 women). Baseline AV nodal effective refractory period (ERP) was 272 ± 57 ms, postprocedural 331 ± 64 (P < 0.001), and the mean of the difference (Δ ERP) 60 ± 41. At the end of the procedure, 64 patients (21 %) had a residual jump, of whom 22 with a single echo. At 12 months follow-up, the actuarial recurrence-free rate was 70.3 % in patients with a residual jump and 86 % in those without (P = 0.01). In patients with a jump, only Δ AV nodal ERP was correlated with recurrence (37 ± 41 vs. 68 ± 47 ms; P < 0.04) while a single echo was not. The actuarial rate of recurrence was 60.8 % in patients with a Δ AV nodal ERP ≤ 30 ms and 18.8 % in those with a Δ AV nodal ERP >30 ms (P < 0.01).

CONCLUSIONS

Suppression of slow pathway conduction is the optimal endpoint for AVNRT cryoablation. A residual jump can be tolerated if AV nodal ERP postcryoablation is prolonged >30 ms.