Role Of Modified Lewis Lead In The Differential Diagnosis Of Wide QRS Complex Tachycardia

Objective:The differential diagnosis of wide QRS complex tachycardia(WCT)is a difficult point in clinical work,and about 80%of WCT are ventricular tachycardia(VT).Atrioventricular dissociation is one of the most specific criteria for VT diagnosis,however it can only be identified by standard 12 electrocardiogram(ECG)in 30%of such cases.Lewis lead is a feasible way to amplify the P wave amplitude in atrial fibrillation,which is also reported in a few cases of WCT differential diagnosis.Furthermore,the modified Lewis lead is also a promising solution for P wave amplitude enhancement and identification of atrioventricular relationship in ECG.In this research,we aim to increase the P wave recognition during WCT by a modified Lewis lead approach.Methods:The modified Lewis lead is set as moving the right arm electrode to the sternal manubrium and left arm electrode to the right fourth intercostal space,the other leads are consistent with the standard leads.WCT are simulated by right ventricle(RV)and left ventricle(LV)pacing with different circle length(CL)(S1S1,300ms,350ms,400ms and 500ms)in 82 patients of the left side AV accessory pathway after successfully ablated by trans-septal approach.Both standard 12 lead ECG and modified Lewis lead ECG(25mm/s,10 mV)are taken and the P wave recognition are analyzed separately.Results:The P wave recognition by modified Lewis lead ECG is higher than those achieved by standard 12 ECG(58.4%± 11.2%vs 30.5%±9.1%,P<0.05).The P wave recognition of different pacing CL are higher in each modified Lewis lead ECG group,and the lowest recognition is at 300ms(P<0.05).The P wave recognition of RV in modified Lewis lead ECG group is not significantly different from that of LV,with no statistical difference(P>0.05),but both are significantly higher than that in the standard 12 lead ECG group.Conclusion:Recording of modified Lewis lead ECG is feasible to increase the P wave recognition in WCT,which is a simple way to improve the accuracy of differential diagnosis in WCT.