| Background and objective:Atrial fibrillation(AF)is one of the most common arrhythmias in clinical practice.Catheter ablation,including radiofrequency ablation and cryoablation,is widely used for the treatment of AF.However,some patients require electrical or drug conversion to restore sinus rhythm after ablation.Nifekalant(NIF)is a class III potassium channel blocker marketed in China in recent years.It has a single electrophysiological effect in antiarrhythmic therapy.NIF mainly blocks the rapid delayed rectifier potassium current(Ikr)through prolonging the action potential duration(APD)and effective refractory period(ERP)in atrium and ventricle.The characteristics of NIF are rapid effect,short half-life and absence of negative inotropic effect.It is mainly used for refractory ventricular tachycardia and ventricular fibrillation.In recent years,NIF has been explored to treat atrial arrhythmia,including atrial flutter and atrial fibrillation.This study will observe the efficacy and safety of NIF to convert AF in patients after radiofrequency ablation,and try to investigate the relevant factors that influence cardioversion.Methods:We enrolled 74 consecutive AF patients who were admitted to the Second Affiliated Hospital of Nanchang University and had experienced radiofrequency ablation between 1.Nov.2016 and 31.Mar.2018.All the patients signed the informed consent.Intravenous NIF were administered in five minutes after ablation with a dose of 0.4mg/kg.We observed the cases of AF converting to sinus rhythm and the changes of heart rate,QT interval and QTc interval before the medication and 5min,10 min,20min,120 min after the medication.The emerging arrhythmia,discomfort and other relevant information were also observed.According to the conversion of AF after the administration of NIF,patients were divided into cardioversion group and non-cardioversion group.At the same time,subjects' general clinical data,laboratory test results and echocardiographic data were collected.SPSS 22.0 statistical software was used for data analysis.Measurement data are measured by normality,and if the data that follow the normal distribution are expressed as mean±standard deviation(x ±s)and t-test is used.If the date are not identical to the normal distribution,they are expressed as M(Q25,Q75)and non-parametric test is used.Count data is expressed as n(%),using X2 test.All statistical tests were performed using a two-sided test,P<0.05 was considered statistically significant.Result:1.A total of 74 patients were included in the study,aged 44 to 84 years old(64±9 years old),40 males and 34 females;a total of 45 patients were converted,and the overall success rate was 60.8%.There were 49 cases of persistent AF,of which 27 cases were cardioversion and the success rate was 55.1%.There were 25 cases of paroxysmal AF,of which 18 cases were cardioversion and the success rate was 72.0%.The cardioversion time was 1.5 to 12 minutes(5.6±3.0 min).2.QT interval and QTc interval before treatment were 359.02±55.68 ms and 450.22±54.69 ms.After NIF injection,it began to prolong.5min(406.37±58.05 ms,493.06±50.35ms)was prolonged obviously,about 10min(427.90±66.21)(ms,504.78±44.26ms)reached the peak,20min(407.41±55.76 ms,476.92±42.05ms)significantly shorter than 10 min,the difference was statistically significant(P< 0.001).To the 120 min QTc interval(440.27±38.65ms),there was no significant difference between the levels before and after drug administration(t=1.14,P=0.26).3.Torsades de pointes(TdP)and other malignant arrhythmias did not appear in all subjects.The occurrence of arrhythmias included bradycardia(2.7%),frequent early and short ventricular tachycardia(2.7%).Adverse reaction like bolus injections,pain,and phlebitis did not appear.4.There was a significant difference in age between the cardioversion group and the non-cardioversion group(P<0.05).The cardioversion rate between the 75-year-old group and the <75-year-old group was significantly decreased,but there was a statistically significant difference between the two groups in LAD.(P>0.05).5.In patients with persistent AF,the AF duration 20(13,36)months in the cardioversion group was significantly shorter than that in the non-cardioversion group(22,37)months,and the difference was statistically significant(P<0.05).Conclusion:The overall successful cardioversion ratio of NIF in AF patients after radiofrequency ablation is 60.8%,and it can reach 72% in patients with paroxysmal AF.Besides,NIF has the advantage of short time to cardioversion and less adverse drug reaction.In present study,age and AF duration are related to the results of NIF in cardioversion in AF patients after radiofrequency ablation. |
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