体表心电图特征对特发性右心室流出道室性心动过速和室性早搏起源点的定位价值

目的 起源于右心室流出道(RVOT)不同位点的室性心动过速(VT)具有相应的心电图表现,本研究旨在摸索一种相对简单的根据体表心电图进行定位的方法 .方法 将RVOT分为游离壁和间隔而两大区,其中间隔面又分为9个区域.共320例RVOT-VT患者中,对213例既往消融成功患者的靶点与体表12导联心电图中QRS波形态之间的关系进行分析,并在消融前前瞻性地对另外107例患者的消融靶点进行预测,以检验其定位价值.结果 I导联对RVOT起源的VT有特殊的定位价值.在间隔面前部起源时,I导联以负向波为主,多为QS、Qr及rS型,随着起源点从前向后、从上向下,R波逐渐升高,其中起源于间隔侧中带(2、5、8区)时,以"M"型居多,在后壁时则表现为R波且有切迹.游离壁起源者的QRS时限明显延长,I和aVL导联的R波较间隔起源者高,而下壁导联的R波均较间隔的低(P<0.05).在前瞻性分析中,这些参数的敏感度、特异度、阳性和阴性预测值均较高.结论 RV-OT不同部位起源的VT有相应的心电图特征,其中I导联形态尤其具有定位价值,为RVOT心律失常起源提供了简便的定位标准.

Localization of the origin of idiopathic ventricular tachycardia from right ventricular outflow tract by surface electrocardiogram

Objective The characteristics on 12-lead electrocardiogram(ECG) are useful in the identi-fication of idiopathic right ventricular outflow tract(RVOT) tachycardia origins. This study was aimed to develop a relative simple algorithm for localization the origin of RVOT ventricutar tachycardia(VT) or premature ventric-ular contraction(PVC)based on ECG. Methods The RVOT was anatomically classified into septum and free wall and the septum area was subdivided into nine regions. An algorithm was developed by correlating the ECG findings with the catheter ablation sites in 213 patients with RVOT VT/PVC. The algorithm was prospectively used to localize the origin of RVOT VT/PVC in 107 patients before ablation. Results The QRS morphology in lead I has a high specific diagnostic value for arrhythmia. Foci originating from anterior RVOT septal sites 3,6, 9 produced a dominant negative wave(QS,Qr or rS). R wave progression in Lead I from anterior to posterior or from superior to inferior septal RVOT was observed. The specific "M" type was mostly recorded in medium sep-tal RVOT(sites 2,5,8)and the notch in R wave was observed in posterior septum. In patients with RVOT free wall origin,the longer QRS duration was observed,with a taller R wave in Lead I and aVL,and a lower R wave in inferior leads(compared with the RVOT septum origin,P<0.05). In the prospective analysis,these parame-ters had a higher sensitivity,specificity with higher positive predictive value as well as negative predictive val-ue. Conclusion The ECG characteristics,especially QRS morphology in Lead I can serve as a useful and sim-ple template in predicting accurate origin site of RVOT arrhythmia.