ECG Analysis Of Premature Ventricular Contraction Originating From Outflow Tractor

Objective: We have retrospectively analyzed the electrocardiography(ECG)of premature ventricular contraction(PVC)originating from ventricular outflow tract who underwent successful radiofrequency ablation treatment.Combined with the electrocardiogram location method that literature reported,we take a further summary of the characteristics of the electrocardiography of PVC,and compared the accuracy of the four methods to identify the originating point of the precordial lead R/S migration ?V3 of PVC to guide the radiofrequency ablation.Method: We analyzed the electrocardiograms of 162 PVC patients originating from outflow tract who after successful radiofrequency ablation treatment,We observed and measured the pattern,amplitude and duration of the every QRS-wave,amplitude and duration of R-wave and S-wave,and calculated V1?V2 R-wave duration and R/S-wave amplitude indices?the V2 transition ratio ?the transitional zone(TZ)index?the Sv2/Rv3 index.Results: According to R/S transmigration on V4-V6,we judged that the PVC originates respectively from right ventricular outflow tract(RVOT)with 70.80% sensibility and 84% specificity and the positive predictive value reaches 96.04%.According to the transition zone index ?0,we judge that the PVC originates from RVOT with 94.16% sensibility and 80% specificity,and the positive predictive value reaches 96.27%.If ECG met the index of the V1 R/S-wave amplitude ?30% and the R-wave duration ?50%,we judged that the PVC originates from LVOT with 72% sensibility and 97.81% specificity,and the positive predictive value reaches 85.71%.Analyzed 109 PVC patients originating from RVOT septum and 19 PVC patients originating from RVOT free wall,found that the duration of QRS-wave of RVOT free wall is longer than that of RVOT septum,and incisura is found in the inferior wall lead R-wave of 73.68% RVOT free wall,while the data in the septum is only 15.69%.Through the analysis of 14 PVC patients originating from aortic sinus,we found that the lead II,III,and lead a VF present as a high and vertical R-wave,and precordial leads R/S mostly migrate before V3.For instance,in lead?,the main wave is upright of R with R(?)smaller than R(?)and QS(a VR)smaller than QS(a VL),which conforms to the PVC originating from left coronary cusp(LCC),if the main of wave lead I is downward of S wave,and R(?)larger than R(?)and QS(a VR)larger than QS(a VL),conforming to the PVC originating from right coronary cusp(RCC).Compared the accuracy of the four methods to identify the originating point of the R/S migration on V1-V3,all areas under the ROC curve of the four methods are over 0.86,the biggest area of the transition zone index is 0.9190.The sensibility of the Sv2/Rv3 index reaches to the highest of 95.24%.Conclusion: The RVOT-PVC mostly shows R/S transmigration on V4-V6,while the most part of the left ventricular outflow tract(LVOT)PVC shows R/S transmigration on V1-V2.TZ can be used to judge the PVC originating position.If TZ ?0,we can judge that the PVC originates from RVOT with high sensibility and specificity.If the index of the V1 R/S-wave amplitude ?30% and the R-wave duration ?50%,we can judge that the PVC mostly originates from LVOT with higher specificity.According to the incisure on the inferior wall R-wave,we can judge PVC originates from RVOT septum or free wall.If the PVC originates from different positions of aortic sinus,then the characteristics of electrocardiography are different which can be identified by the lead I QRS-wave direction,lead II?III R-wave amplitude and a VL and a VR lead QS-wave amplitude.V1 R-wave duration and R/S-wave amplitude indices?the V2 transition ratio ? the transitional zone(TZ)index ? the Sv2/Rv3 index all have a high application value for identifying the originating position of the outflow tract PVC of R/S migration on V1-V3.