The Value Of Electrocardiographic Diagnosis For Differentiating The Origin Of Right Ventricular Outflow Tract Ventricular Arrhythmias

Objective To investigate the value of body surface electrocardiogram(ECG)in judging the origin of right ventricular outflow tract ventricular arrhythmias.Methods A total of 165 patients with ventricular premature beats and ventricular tachycardia who were admitted to the First Affiliated Hospital of Guangxi Medical University from January 2014 to June 2019 were selected.Preoperative body surface electrocardiogram(ECG),24-hour dynamic electrocardiogram,transthoracic echocardiography,Cardiolateral radiograph and etc.Intracardiac electrophysiological examination and catheter radiofrequency ablation under the guidance of 3D mapping system and X-ray.The characteristics of the electrocardiogram of the preoperative body and the electrogram of the target cavity were successfully retrospectively analyzed.Results The origin of ventricular arrhythmia was determined by intracardiac electrophysiological examination in 165 patients and the onset of ventricular arrhythmia was terminated by transcatheter radiofrequency ablation.Among them,103 cases of ventricular arrhythmia were on the right ventricular outflow tract pulmonary valve,age(46.8 ± 13.1),male 22 cases.62 cases of ventricular arrhythmia were under the pulmonary valve,age(47.6 ± 17.1),male 21 cases,consist of 20 cases on the anterior septum,8 cases on the middle septum,14 cases on posterior septum,11 cases on the anterior free wall,9 cases on the posterior free wall.The ECG of the preoperative body surface of all patients was left bundle branch block,Leads Ⅱ,Ⅲ,and a VF had high amplitude R waves,Leads a VL and a VR were QS.Lead ventricular outflow tract septum interval Ⅱ,Ⅲ,and a VF leads show unidirectional R waves,no notch,sensitivity of 84%,and specificity of 68%;QS amplitude of lead a VL ≥QS amplitude of lead a VR,sensitivity of 86%,and specificity of 70 %.Free wall Ⅱ,Ⅲ,and a VF leads show R waves,but the peaks or falling notches of R waves have a sensitivity of 68%and specificity of 84%.QS amplitude of a VL < QS amplitude of a VR,sensitivity of 70%,and specificity of 86%.Lead I is QS,rs,or rs R,which indicates 70% sensitivity and 82% specificity of anterior septum or anterior free wall.Lead I was rs-shaped(both r-wave amplitude and s-wave amplitude≤0.05mv),with a sensitivity of 71% and a specificity of 94%.Lead I showed an R wave with a posterior septum or posterior free wall with a sensitivity of 81%and a specificity of 78%.Compared with the under the pulmonary valve group,the ventricular arrhythmia up the pulmonary valve group was in the Ⅱ,Ⅲ,a VF lead R wave amplitude,the Ⅱ + Ⅲ lead R wave amplitude,the Ⅱ + a VF lead R wave amplitude,the Ⅲ + a VF lead R wave amplitude,and the Ⅱ + Ⅲ + a VF lead R wave amplitude were larger than that of under the pulmonary valve group(P <0.05).According to the ROC curve analysis was performed,in which the area under the R-wave amplitude curve of the lead of the ventricular rhythm Ⅱ was the largest,which was 0.613.Therefore,the R wave amplitude of lead Ⅱ of the ventricular rhythm was used as an index to distinguish the upper and lower pulmonary valves,and the R wave amplitude ≥1.85 mv was used as the threshold to identify the target points on the right ventricular outflow tract pulmonary valve.Its sensitivity is 65% and its specificity is 51.6%.Conclusion Body surface electrocardiogram(ECG)is left bundle branch block,lead Ⅱ,Ⅲ and a VF lead show unidirectional R wave,the QS amplitude of a VL≥the QS amplitude of a VR,which is helpful for judging the origin of right ventricular outflow tract septum ventricular arrhythmias.Peaks or descending branch notches of R waves in leads Ⅱ,Ⅲ,and a VF,the QS amplitude of a VL <the QS amplitude of a VR,which is helpful for judging the origin of free wall ventricular arrhythmias.The lead value of lead Ⅱ amplitude ≥1.85 mv has certain clinical value for judging the origin of the pulmonary valve on the right ventricular outflow tract.