| Background:Idiopathic premature ventricular contractions (PVCs) originating from the rightventricular outflow tract (RVOT) is one of the common of idiopathic ventriculararrhythmia. Frequent idiopathic RVOT-PVCs may cause left ventricular dysfunctionor tachycardiomyopathy. The anti-arrhythmic drug’s curative effect is poor and it canlead to arrhythmic. However, rodiofrequence cathater ablation (RFCA) can not onlycure idiopathic PVCs, but also improve the cardiac function. Previously, we identifythe target sites in ablation mainly depending on the system with software tool (calledTracking Virtual) by Ensite Array noncontact mapping system. But the accuracy ofthe software tool positioning is limited by other factors.The lack of the ability torecognize the ablation target sites results in a number of invalid discharges inineffective targets. It also aggravates the patients with endocardium damage.Therefore, it needs to study other electrophysiological indexes to facilitate TrackingVirtual， thus to increase the accuracy of an effective target of idiopathicRVOT-PVCs.Objective:The purpose of this study was to analysis the difference between the successfuland failure target of virtual unipolar electrograms from non-contact mapping ofidiopathic RVOT-PVCs.And discuss the value of some form and/orelectrophysiological features of virtual unipolar electrograms for predicting asuccessful ablation target in RVOT-PVCs.Methods:23patients undergoing RFCA by Ensite Array non-contact mapping syetem foridiopathic RVOT-PVCs were studied. According to the results of ablation target canbe divided into two groups (successful target group and failure target group).Comparison between the two groups of the virtual unipolar electrograms of thefollowing characteristics:(1) the local earliest activation to QRS onset time(V-QRS),(2)the height of r wave(r),(3)the height of S wave of the local activation after 3ms,5ms,10ms(VS3,VS5,VS10),(4)the height of the largest negative S wave(S),(5)thepeak of r to the valley of S time(r-S).And using statistical methods such asmultiariable Logistic regression analysis and ROC curve, analyed above indicators invirtual unipolar electrograms for predicting the value of the effective targets.Results:1.23patients with RVOT-PVCs had done RFCA by Ensite array noncontactmapping successfully, with mapping time26.8±7.5min,ablation time356.4±76.8s,X-ray exposure time19.2±4.7min,operative time86.4±16.3min.2. The V-QRS, VS3and VS5of the virtual unipolar electrograms in successfultarget group were bigger than those in failure target group;But r and r-S were smallerthan those in failure target group;There was no statistical significant differencebetween VS10and S in the two groups.3. Multiariable Logistic regression analysis showed that V-QRS and VS5of thevirtual unipolar electrograms were the independent factor for predicting the effectivetargets.(VS5： OR=4.918,95%CI:1.622-14.593,P=0.002;V-QRS： OR=3.625,95%CI:1.027-11.945, P=0.004).4. ROC curve analysis showed that the area under the curve of V-QRS was0.793, and the best diagnostic threshold was13.5ms for predicting the effectivetargets. The sensitivity and specificity were63.3%and85.1%when the virtualunipolar electrograms of V-QRS＞13.5ms;The area under the curve of VS5was0.793,and the best diagnostic threshold was0.26mV for predicting the effectivetargets. The sensitivity and specificity were100%and23.9%when the virtualunipolar electrograms of VS5＞0.26mV; The sensitivity and specificity were75.5%and80.6%when combined the virtual unipolar electrograms of V-QRS＞13.5mswith VS5＞0.26mV for predicting the effective targets.Conclusions:Applicating Ensite Array non-contact mapping system to guide ablation ofRVOT-PVCs, the virtual unipolar electrograms of V-QRS and VS5may be theindependent factor for predicting the effective targets. In addition, combined thevirtual unipolar electrograms of V-QRS＞13.5ms with VS5＞0.26mV can improvethe accuracy of target localization significantly. |
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