Differentiating origins of outflow tract ventricular arrhythmias: a comparison of three different electrocardiographic algorithms

Our objective is to evaluate the accuracy of three algorithms in differentiating the origins of outflow tract ventricular arrhythmias (OTVAs). This study involved 110 consecutive patients with OTVAs for whom a standard 12-lead surface electrocardiogram (ECG) showed typical left bundle branch block morphology with an inferior axis. All the ECG tracings were retrospectively analyzed using the following three recently published ECG algorithms: 1) the transitional zone (TZ) index, 2) the V2 transition ratio, and 3) V2 R wave duration and R/S wave amplitude indices. Considering all patients, the V2 transition ratio had the highest sensitivity (92.3%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (93.9%). The latter finding had a maximal area under the ROC curve of 0.925. In patients with left ventricular (LV) rotation, the V2 transition ratio had the highest sensitivity (94.1%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (87.5%). The former finding had a maximal area under the ROC curve of 0.892. All three published ECG algorithms are effective in differentiating the origin of OTVAs, while the V2 transition ratio, and the V2 R wave duration and R/S wave amplitude indices are the most sensitive and specific algorithms, respectively. Amongst all of the patients, the V2 R wave duration and R/S wave amplitude algorithm had the maximal area under the ROC curve, but in patients with LV rotation the V2 transition ratio algorithm had the maximum area under the ROC curve.

本研究旨在评估三种算法鉴别流出道室性心律失常（OTVAs）起源部位的准确性。本研究纳入110例连续入选的流出道室性心律失常患者，其标准12导联体表心电图（ECG）均呈现典型左束支传导阻滞形态伴电轴下偏。研究对所有心电图波形进行回顾性分析，采用以下三种新近发表的心电图算法：1）移行区（TZ）指数；2）V2移行比率；3）V2导联R波时限及R/S波振幅指数。对全部患者而言，V2移行比率的灵敏度最高（92.3%），而V2导联R波时限及R/S波振幅指数的特异度最高（93.9%），后者的受试者工作特征曲线（ROC曲线）下面积最大值为0.925。在左心室旋转（LV）亚组患者中，V2移行比率的灵敏度最高（94.1%），V2导联R波时限及R/S波振幅指数的特异度最高（87.5%），前者的ROC曲线下面积最大值为0.892。三种已发表的心电图算法均可有效鉴别流出道室性心律失常的起源部位，其中V2移行比率与V2导联R波时限及R/S波振幅指数分别为灵敏度最高与特异度最高的算法。全部患者队列中，V2导联R波时限及R/S波振幅算法的ROC曲线下面积最大；而在左心室旋转（LV）亚组患者中，V2移行比率算法的ROC曲线下面积最大。