Improving pulmonary vein isolation during cryoballoon ablation using the re-look angiography technique

Background Cryoballoon ablation for pulmonary vein (PV) antral isolation is contact-dependent. Currently, occlusion assessment using the cryoballoon is most commonly performed using contrast venogram prior to ablation. However, there is a known difference in balloon size/shape between the inflated and ablation state, due to significant increase in cryoballoon pressure, which can cause potential undetected leak and, thus, failure of PV isolation. This phenomenon is currently not detected using standard techniques and effectiveness of mitigation techniques have not been assessed. Purpose We hypothesize that repeat injection of contrast five seconds after the initiation of cryoballoon ablation can be used to assess changes in shape and confirm ongoing occlusion during ablation; the re-look angiography technique. The incidence of PVI leak and the ability for the relook angiography to remedy the leak is assessed. Methods A total of 125 patients (440 PVs) undergoing cryoballoon ablation (Medtronic Arctic Front Advance Balloon™) were assessed using the re-look angiography technique unless they required occlusion with a segmental approach. Fifteen patients were excluded from contrast use due to renal insufficiency. Results Successful single occlusion was seen in 330 (75%) PVs and the re-look angiography technique was employed in each of those events. In 180 of the 330 (55%) single PV occlusions, a new PV leak undetected during the initial PV angiogram was identified. This prompted repositioning of the balloon to achieve complete PV isolation in 85 of 180 of the PV cases, with 95 of the cases requiring additional segmental ablation to complete full PV isolation. Conclusion A significant amount of insufficient PV antral contact during cryo-ablation may not be detected with conventional single PV angiography and may explain inadequate PV isolation. The re-look angiography technique is a simple tool to confirm robust balloon contact and guide repositioning as well as identify the need for additional segmental ablation. Additional follow up is needed for translation to improved clinical outcomes. Funding Acknowledgement Type of funding source: None

Radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique: 4-year follow-up

Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. Cryoablation has been shown to be a safe and effective technique for pulmonary vein isolation. However, there is a significant arrhythmia recurrence rate after cryoablation procedures and there are no established strategies for redo procedures in these patients. Therefore, we have summarized our experience with radiofrequency catheter ablation for redo procedures after pulmonary vein isolation with the cryoballoon technique (including an analysis of pulmonary vein conduction recovery patterns ater procedures performed with the first or second generation cryoballoon). Methods One hundred and fifty patients (paroxysmal AF: 99 patients, persistent AF: 51 patients) had to undergo a redo procedure after initially successful circumferential PV isolation with the cryoballoon technique (Arctic Front Balloon: 75 patients (group A); Arctic Front Advance: 75 patients (group B)). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (CARTO) depending on the intra-procedural findings. Results During the redo procedure, a mean number of 1.7 re-conducting PVs were detected (using a circular mapping catheter; group A: 2.1 re-conducting PVs, group B: 1.3 re-conducting PVs). There was a slightly higher incidence of chronic PV reconnections related to the left-sided PV ostia than to the right-sided PVs in both groups. Furthermore, sites of chronic PV reconnection were found more frequently in the inferior parts of the PV ostia than in the superior parts. In 65 patients in group A, a segmental approach was sufficient to eliminate the residual PV conduction because there were only a few recovered PV fibers (1–3 reconnected PVs; group A1). In the remaining 10 patients in group A, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction of all four pulmonary veins (group A2). In group B, a segmental approach was sufficient in all patients because there was only a minor reconnection of 1–2 PVs. All recovered PVs could be isolated sucessfully again. At 48-month follow-up, 74.7% of all patients were free from an arrhythmia recurrence (112/150 patients; group A: 51/75 patients (68%), group B: 61/75 patients (81.3%)). There were no major complications in both groups. Conclusions In patients with an initial circumferential PVI using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation. In most cases only a few re-conducting PV fibers were found and therefore, a segmental re-ablation approach seems to be sufficient in the majority of patients (especially in patients treated with the second generation cryoballoon). Funding Acknowledgement Type of funding source: None