| Objective:To investigate the characteristics of intracavity bipolar electrograms during sinus rhythm among effective ablation targets of idiopathic ventricular arrhythmias(VAs)arising from right ventricular outflow tract(RVOT)and to provide help for radiofrequency catheter ablation.Methods:One hundred and thirty-two consecutive patients with VAs originating from RVOT who received successful radiofrequency catheter ablation in Shenyang Northern Hospital were enrolled from January 2021 to August 2022,and 134 VAs were analyzed.The laboratory examinations,echocardiography,12-lead electrocardiogram(ECG),24-h Holter were arranged for all patients before the procedure to exclude any structural heart disease.Guided by three-dimensional mapping system and X-ray image,patients underwent catheter ablation and were divided into three groups according to the location of targets on RVOT:left cusp and corresponding area(LC-CA),right cusp and corresponding area(RC-CA)and anterior cusp and corresponding area(AC-CA).Local intracardiac bipolar electrograms of effective targets during sinus rhythm were analyzed,according to the characteristic,morphology and amplitude,and the electrograms were further defined as the following:(ⅰ)late low-amplitude single potentials;(ⅱ)high-amplitude sharp potentials;(ⅲ)late fractionated potentials;(ⅳ)late compound potentials;(ⅴ)no specific potentials;the first four type potentials were defined delayed potentials.Surface ECG characteristics,bipolar electrogram characteristics of different regions,acute procedural success,clinical outcomes were analyzed.Results:The successful ablation sites were located in LC-CA in 81(60.45%)patients,in RC-CA in 30(22.39%)patients,and in AC-CA in 23(17.16%)patients.The successful target sites were located at sinus cusps above the pulmonary valve in 26(19.40%)patients.During sinus rhythm,late potentials were recorded in 96 of 134(71.64%)patients.Among the 96 patients,11/96(11.46%)patients presented a late low-amplitude single potential,40/96(41.67%)patients exhibited a high-amplitude sharp potential,39/96(40.63%)patients showed a late fractionated potential,and 6/96(6.25%)showed a late compound potential.In addition,reversal of the late potentials prior to the local far field ventricular electrogram during VAs were noted in 49 of the 96 patients(51.04%).The incidences of late potentials in three groups were similar(66.67%in LC-CA,83.33%in RC-CA,and 73.91%in AC-CA,all P>0.05),and there were no differences in the occurrence of five types of potentials among the three groups(P>0.05).The ablation time in patients with late potentials were shorter than that in patients without specific potentials(23.32± 12.44min vs.30.61 ±9.80min,P<0.05),but no significant differences were found in V-QRS time,fluoroscopic time,acute successful rates,recurrence rates and long-term successful rates.132 patients(98.51%)had acute success after ablation,and VAs were disappeared the day after the procedure in the two patients without acute success.No serious complications such as pericardial tamponade occurred during and after procedures.Conclusion:Late potentials recorded by bipolar electrograms in the target sites during sinus rhythm were found in 71.64%patients with idiopathic VAs arising from right ventricular outflow tract,which mainly consisted of late high-amplitude sharp potentials and late fractionated potentials.The VAs with late potentials had shorter ablation time than those without specific potentials,but there was no significant difference between the acute successful rate and the long-term successful rate.Searching for delayed potential under sinus rhythm can assist in mapping and ablating RVOT-VAs,improve the efficiency of ablation procedures,and is a safe and feasible method. |
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