Fassini G, Riva S, Della Bella P, Carbucicchio C, Tondo C
Istituto di Cardiologia, Università degli Studi, IRCCS, Milano.
Cardiologia. 1996 Sep;41(9):869-75.
In view of the growing role of catheter ablation techniques for the treatment of supraventricular tachycardia, noninvasive determination of tachycardia mechanism and preliminary localization of the accessory pathway (AP) can simplify the cardiac catheterization procedure and reduce fluoroscopic exposure. The purpose of this study was to analyze the diagnostic value of repolarization changes during narrow QRS complex tachycardia (< 0.11 s). In 159 12-lead electrocardiograms during narrow QRS complex tachycardia (13 atrial tachycardias, 57 atrioventricular (AV) node reentrant tachycardias and 89 AV reciprocating tachycardias), the following were evaluated: 1) the tachycardia cycle length; 2) the presence of QRS alternans > or = 1 mm in at least 6 leads; 3) the presence of ST segment depression > or = 2 mm and/or T wave changes (inversion, notching); 4) the duration of retrograde atrial activation during tachycardia (right atrium-coronary sinus interval, in ms); the latter parameter, as well as tachycardia mechanism and accessory pathway location, were determined during an electrophysiologic study. There were no significant differences in mean cycle length among the groups. ST segment depression > or = 2 mm and/or T wave changes were present more often in AV reciprocating tachycardias (51/89) than in the other groups (AV node reentrant tachycardias: 14/57; atrial tachycardias: 1/13; p < 0.001), independently from the cycle length. Distinct patterns of repolarization changes during tachycardia were associated with different location of accessory pathway: ST segment depression from V3 to V6 in left lateral AP; T wave inversion in inferior leads in posterior-posteroseptal AP; T wave changes in V2 in all cases of anteroseptal AP location. The magnitude of ST segment depression, significantly more marked in the AV reciprocating tachycardias (1.3 +/- 1.6 mm) than in AV node reentrant tachycardias (0.7 +/- 0.8 mm, p < 0.005), was directly related to the duration of atrial activation time during tachycardia (80 +/- 20 ms, and 32 +/- 12 ms, p < 0.001, respectively). The finding of ST segment depression and/or T wave changes during narrow QRS tachycardia suggest the presence of an AV reciprocating tachycardia; this phenomenon may be related to a different pattern of retrograde atrial activation. In conclusion, analysis of repolarization changes during narrow QRS tachycardia constitutes an additional electrocardiographic criterion to differentiate the tachycardia mechanism and, furthermore, can guide preliminary location of the AP, even in the absence of ventricular preexcitation.
鉴于导管消融技术在室上性心动过速治疗中发挥着越来越重要的作用，非侵入性确定心动过速机制及旁路（AP）的初步定位可简化心脏导管检查程序并减少透视暴露。本研究的目的是分析窄QRS波群心动过速（<0.11秒）期间复极变化的诊断价值。在159份窄QRS波群心动过速时的12导联心电图（13例房性心动过速、57例房室（AV）结折返性心动过速和89例AV折返性心动过速）中，评估了以下内容：1）心动过速周期长度；2）至少6个导联中QRS波群交替电压≥1毫米；3）ST段压低≥2毫米和/或T波改变（倒置、切迹）；4）心动过速期间逆行心房激动的持续时间（右心房-冠状窦间期，单位为毫秒）；后一参数以及心动过速机制和旁路位置在电生理研究期间确定。各组间平均周期长度无显著差异。ST段压低≥2毫米和/或T波改变在AV折返性心动过速（51/89）中比在其他组（AV结折返性心动过速：14/57；房性心动过速：1/13；p<0.001）中更常见，与周期长度无关。心动过速期间复极变化的不同模式与旁路的不同位置相关：左侧旁路时V3至V6导联ST段压低；后间隔-后侧壁旁路时下壁导联T波倒置；前间隔旁路定位的所有病例中V2导联T波改变。ST段压低的幅度在AV折返性心动过速（1.3±1.6毫米）中比在AV结折返性心动过速（0.7±0.8毫米，p<0.005）中明显更显著，与心动过速期间心房激动时间的持续时间直接相关（分别为80±20毫秒和32±12毫秒，p<0.001）。窄QRS波群心动过速期间ST段压低和/或T波改变的发现提示存在AV折返性心动过速；这种现象可能与逆行心房激动的不同模式有关。总之，分析窄QRS波群心动过速期间的复极变化构成了区分心动过速机制的一项额外心电图标准，此外，即使在无室性预激的情况下也可指导旁路的初步定位。
