The Approach To Terminate Atrial Fibrillation In The Ablation And The Outcome After Catheter Ablation And Atrial Substrate In Patients With Atrial Fibrillation

BackgroundCatheter ablation for non-paroxysmal atrial fibrillation(AF)is associated with less favorable outcome.Pulmonary vein isolation is the cornerstone of AF ablation.Nevertheless,AF termination during or upon completion of pulmonary vein isolation(PVI)only occurs in the minority of patients with non-paroxysmal AF.Ibutilide,which is a class ? AAD,is used to terminate atrial fibrillation to facilitate the ablation.This study aimed to assess the relationship between the cardiac rhythm response to ibutilide infusion and the recurrence of long-term atrial arrhythmias.MethodsOne hundred and thirty-eight patients with non-paroxysmal AF who had their first catheter ablation were retrospectively included.All patients whose atrial fibrillation did not terminate after pulmonary vein isolation were administered intravenous ibutilide(1.0 mg).Those with atrial fibrillation termination after ibutilide administration were defined as responders(n=86);those without atrial fibrillation termination,as non-responders(n=52).The primary end point was any documented atrial arrhythmia recurrence lasting>30 s after the initial catheter ablation.ResultsThe average age of the overall included patients was 61±10 years,while 73.6%were male,and 32.6%had long-standing persistent AF.Atrial fibrillation conversion to sinus rhythm,directly or via atrial flutter,by ibutilide administration was achieved in 62.3%of patients.A longer atrial fibrillation duration was associated with failed atrial fibrillation termination(odds ratio 1.009,95%confidence interval 1.002-1.017,P=0.011).During a median follow-up period of 610 days(interquartile range,475-1106)post ablation,non-responders(n=24,46.2%)had a higher atrial arrhythmia recurrence rate than responders(n=26,30.2%;log-rank,P=0.011)after the initial catheter ablation.Multivariate Cox regression analysis revealed that non-responders(hazard ratio 1.994,95%confidence interval 1.117-3.561,P=0.020)was significantly correlated with atrial arrhythmias recurrence.ConclusionIn patients whose atrial fibrillation persisted after pulmonary vein isolation,response to ibutilide administration could predict atrial arrhythmias recurrence after catheter ablation,which may be useful for AF recurrence risk stratification and individualized AF management.BackgroundAtrial fibrillation(AF)usually persisted after pulmonary vein isolation in some patients with atrial fibrillation,especially with non-paroxysmal AF.Ibutilide is a common practice to terminate AF to facilitate the ablation.The previous study had showed that the response to ibutilide predict the long-term recurrence of atrial arrhythmia after catheter ablation.However,the relationship between the response to ibutilide and left atrial remodeling is unclear.The study aimed to assess the association between the left atrial low voltage zones(LVZ)and the response to ibutilide in patients with AF.MethodsThis was a retrospective study conducted on patients with AF who underwent their first catheter ablation.All patients whose atrial fibrillation did not terminate after pulmonary vein isolation were administered intravenous ibutilide(1.0mg).Those with atrial fibrillation termination after ibutilide administrate were defined as ibutilide responders;those without atrial fibrillation termination,as ibutilide non-responders.All patients underwent bipolar voltage mapping in the sinus rhythm after pulmonary vein isolation.LVZ determined was defined as bipolar voltage amplitude<0.5mV.LVZ presence was defined as LVZ covering>5%of the left atrial surface area.ResultsAltogether,54 patients were included with the average age 62±10 years.Of them,37 patients(68.5%)were male,46 patients(85.2%)had non-paroxysmal AF and 16 patients(29.6%)were ibutilide non-responders.Compared with ibutilide responders,the proportion of LVZ%?9%was higher in the ibutilide non-responders(56.3%vs.21.1%,P=0.011).Based on the extent of left atrial substrate,24 of 38 patients(63.2%)in the ibutilide responders belonged to stage ?,10(26.3%)to stage ?,2(5.3%)to stage ? and 2(5.3%)to stage ?;6 of 16(37.5%)patients in the ibutilide non-responders belonged to stage ?,5(31.3%)to stage ?,1(6.3%)to stage ? and 4(25%)to stage ?.The extent of left atrial LVZ was higher in the ibutilide non-responders than that in the ibutilide responders(P=0.043).The LVZ in the left atrial posterior wall was more observed in the ibutilide non-responders than that in the ibutilide responders(81.3%vs,34.2%,P=0.002).In the multivariate logisitic analysis,The LVZ in the left atrial posterior wall was associated with the efficacy of ibutilide on AF termination(OR 6.653,95%CI 1.495-29.603,P=0.013).ConclusionIn patients whose atrial fibrillation persisted after pulmonary vein isolation,the response to ibutilide administration was associated with the extent of left atrial LVZ and the LVZ in the left atrial posterior wall,that is the patients whose atrial fibrillation persisted after ibutilide administration have higher degree of left atrial LVZ,which could explain they have more long-term atrial arrhythmia recurrence after catheter ablation.BackgroundAtrial fibrillation(AF)termination during or upon completion of pulmonary vein isolation(PVI)occurs in the minority of patients with persistent AF before the ablation.In patients whose atrial fibrillation persisted after pulmonary vein isolation,ibutilide administration and/or direct current cardioversion(DCC)are used for AF termination.In the previous study,the response to ibutilide administration was associated with the extent of left atrial low voltage zones.This study aimed to analyze the relationship between the approach to terminate AF and the electrophysiological substrate.MethodsPatients who were in AF rhythm and underwent first-time catheter ablation were prospectively enrolled.According to the approach to terminate AF,the patients were divided into four groups:patients whose AF terminate during PVI(PVI responders),patients whose AF terminate after PVI with ibutilide administration(ibutilide responders),patients whose AF terminate after PVI with DCC,and patients whose AF terminate after PVI with ibutilide administration and DCC(ibutilide non-responders),in which the last three groups were defined as PVI non-responders.All included patients underwent electroanatomic voltage mapping before ablation and after cardioversion to assess the pulmonary vein sleeve and left atrial voltage.The AF cycle-length was measured before ablation and cardioversion,and before and after ibutilide administration.ResultsAltogether,33 patients were included with the average age 62±10 years,in which 24(72.7%)were male and 21(63.6%)had persistent AF.Of them,4(12.1%)patients were PVI responders,18(54.5%)were ibutilide responders,2(6.1%)whose atrial fibrillation were terminated by the DCC after PVI,9(27.3%)were ibutilide non-responders.Compared with PVI responders,the left atrial volume and left atrial surface area were much larger(98.9±24.2 ml vs.71.0±11.0 ml,P=0.005;101.4±19.3 cm2 vs.74.8±7.5 cm2,P=0.015,respectively),and left superior and left inferior pulmonary vein sleeve were much longer(32.4±7.7 mm vs.19.0±3.8 mm,P=0.003;15.6±4.3 mm vs.8.1 ±5.9 mm,P=0.004;respectively)in the PVI non-responders.Compared with ibutilide non-responders,the baseline AF cycle-length was longer(173±20 ms vs.148 ± 14 ms,P=0.003),and the prolongation magnitude of AF cycle-length induced by ibutilide was larger(96±52 ms vs.49 ± 28 ms,P=0.019)in the ibutilide responders.There was no significance in the area and percentage of left atrial low voltage zones between the groups.ConclusionIn patients who were atrial fibrillation(AF)before ablation,PVI responders had shorter pulmonary vein sleeves,which provided a theoretical basis for only PVI in these patients.For PVI non-responders,the baseline AF cycle-length and the prolongation magnitude of AF cycle-length may be important determinants of ibutilide efficacy for AF termination.