Application Of Ibutilide In The Radiofrequency Catheter Ablation Of Persistent Atrial Fibrillation

Objective:The purpose of this study was to evaluate the relationship between the successful cardioversion of atrial fibrillation(AF)by ibutilide and the left atrial substrate and to select different ablation strategies according to the patients' response to ibutilide.Methods:80 consecutive patients(44 males,36 females,average age 61.89±8.05 years)were selected who underwent radiofrequency catheter ablation for persistent atrial fibrillation between 2019 and 2020.All patients were failed to recover sinus rhythm with bilateral Pulmonary vein isolation(PVI)and Left atrium(LA)roofline ablation.The 1mg ibutilide(0.01 mg/kg if body weight<60 kg)was given to the patient and the dose was repeated after 10 mins of observation if there was no reversion found in patients.The cardioversion was observed after 30 minutes and the adverse reaction after 4 hours onset of the last ibutilide administration.According to whether the cardioversion was successful,the patients were divided into cardioversion group and non-cardioversion group,and the left atrial substrate was modified after the electrical cardioversion in the non-cardioversion group.Results:We found that,out of 80 patients,42 patients(52.5%)converted to sinus rhythm in a single dosage of ibutilide(1mg),while 10 patients(12.5%)converted to sinus rhythm after repeated administration,and the total conversion rate was 65.0%(52 cases).The remaining 28 patients who unable to converted to sinus rhythm,8 patients converted to atrial flutter or atrial tachycardia,and the sinus rhythm was restored after corresponding ablation;20 patients who were still AF(recovered to sinus rhythm after electrical cardioversion)underwent left atrial substrate modification after electrical cardioversion,and finally converted to sinus rhythm.Also found 2 cases of ventricular premature beat and 1 case of sinus bradycardia during medication and no special treatment was given,however,they returned to normal level after 1 hour.We did not observe any of the cases of Torsade de Pointes(Td P),hypotension,and other adverse events.The duration of AF in the cardioversion group was shorter than that in the non-cardioversion group [3.0(2.0-5.0)vs4.0(2.0-5.0)years,P<0.05].The scar and low voltage area of left atrium in non-cardioversion group was significantly higher than that in cardioversion group [15.34(14.26-16.49)vs11.24(9.87-13.40)%,P<0.05].The Left atrium diameter(LAD)was(37.23±3.83)mm in the cardioversion group and(41.58±4.12)mm in the non-cardioversion group(P<0.05).The measured QTc[(476.94±31.45)vs(367.09±24.28)ms,P<0.05] was significantly increased after 30 minutes of ibutilide administration.Moreover,there was a positive correlation between the LAD size and the proportion of scar and low voltage area in the left atrium.There were no significant differences in age,gender,body mass index(BMI),left ventricular ejection fraction(LVEF),NT-pro BNP,High-sensitivity C-reactive protein(hs-CRP)and basic diseases between the two groups(P>0.05).Conclusion:The success rate of cardioversion by ibutilide was related to the duration of AF,LAD,scar and low voltage area of left atrium.A lower success rate of cardioversion in the operation indicate that these persistent AF patients have more severe atrial fibrosis.