Analysis Of The Characteristics Of Frozen Balloon Catheter Pulmonary Vein Isolation

Part One:The value of real-time recording of pulmonary vein potentials during cryoballoon catheter ablation for atrial fibrillationObjective:To investigate the value of real-time recording of pulmonary vein potentials during cryoballoon catheter ablation for atrial fibrillation.Methods:70 patients with AF underwent cryoballoon ablation were consecutively included. Good occlusion of pulmonary veins (PV) was attempted. During ablation, real-time PV potentials were recorded using an integrated circular mapping catheter. After successful PV isolation, a waiting period of 30 minutes was applied to access early reconduction. Reconducted PVs were to cryoablation again to achieve full scale PV isolation at the end of the procedure.Results:57 patients with paroxysmal AF and 13 patients with persistent AF were consecutively included. After an average of 14±4.3 cryoablation applications, PV isolation was achieved in 274 of 282 (97.2%) PVs. Procedural duration was 115.2±24.8 minutes and fluoroscopy time was 29.6±8.9 minutes. Real-time PV potential recording during cryoablation was achieved in 232 (84.3%) PVs. Regarding time to effect, a cut off value of 60s was predictive of persistent PVI with a sensitivity of 0.76 and specificity of 0.82 (area under curve=0.835; p<0.0001). The overall complication rate was 2.8% with two cases of transient hemoptysis and persistent phrenic nerve palsy, respectively.Conclusion:Cryoballoon technique is a feasible, safe and effective technique for pulmonary vein isolation. PV potentials can be recorded in most PVs. The time to effect is predictive of the persistency of PVI.Part Two:Characteristics of redo procedures of patients after pulmonary vein isolation using cryoballoon techniqueObjective:To summarize the characteristics of redo procedures in patients after cryoballoon ablation for atrial fibrillation and to provide guidance for future cryoballoon technique.Methods:From December 2013 to March 2016, nine consecutive patients with prior cryoballoon ablation for atrial fibrillation and recurrent atrial tachyarrhythmia were retrospectively enrolled. All patients underwent radiofrequency irrigation catheter ablation guided by 3-dimentional mapping system for pulmonary vein re-isolation and other inducible tachycardia. The ipsilateral pulmonary vein antrum was divided into six equally distributed segments for the analysis of the location of conduction gaps.Results:All the 9 patients were male with an average age of 48.1 ± 11.5 years. Three patients had persistent atrial fibrillation and 6 patients presented paroxysmal atrial fibrillation. During the prior cryoballoon ablation, all 37 pulmonary veins, including 1 common left pulmonary vein (CLPV),8 left superior pulmonary veins (LSPV),8 left inferior pulmonary veins (LIPV),9 right superior pulmonary veins(RSPV),9 right inferior pulmonary veins (RIPV) and 2 right middle pulmonary veins (RMPV), were successfully isolated using single 28mm cryoballoon with an average of 12.6±1.8 cryoablation applications per one patient. These patients presented recurrent atrial tachyarrhythmia during follow-up and underwent redo procedures in 4.5±2.5 months after the cryoballoon ablation.17 pulmonary veins (45.9%), including 1 CLPV,2 LSPV, 6 LIPV,3 RSPV and 5 RIPV, exhibited reconduction during redo procedures. Among all the 9 paitients, one patient exhibited no pulmonary vein reconduction while other patients exhibited varying numbers of pulmonary vein reconduction. The reconduction sites (19 sites in total) were more frequent in inferior pulmonary veins. All the reconducted pulmonary veins were successfully re-isolated. And radiofrequency ablation was applied in additional superior vena cava isolation in one patient, typical atrial flutter in one patient, peri-mitral atrial flutter in one patient and atrioventricular nodal reentrant tachycardia in one patient. During a median time of 5 months’follow-up, one patient presented recurrent paroxysmal atrial fibrillation which could be well controlled by anti-arrhythmia drugs. The other patients remained sinus rhythm during follow-up.Conclusion:Patients underwent prior cryoballoon ablation for pulmonary vein isolation exhibited relatively lower rate of reconduction, which presented in favored sites (i.e. inferior pulmonary veins). Re-isolation of pulmonary veins, along with additional ablation for other triggers and tachycardia, is effective and safe for the treatment of recurrent atrial tachyarrhythmia.