Drew B J, Scheinman M M
Department of Physiological Nursing, University of California-San Francisco Medical Center 94143-0610.
J Am Coll Cardiol. 1991 Oct;18(4):1025-33. doi: 10.1016/0735-1097(91)90762-x.
To compare the modified precordial leads MCL1 and MCL6 with the conventional precordial leads V1 and V6 and assess the diagnostic accuracy of selected leads for continuous bedside electrocardiographic (ECG) monitoring, 121 wide QRS complex tachycardias were recorded from 92 patients during cardiac electrophysiologic study. As ascertained from intracardiac recordings, 86 tachycardias were ventricular and 35 were supraventricular with aberrant conduction. Early or late peaking of the predominant QRS deflection in lead MCL6 or V6 proved valuable in diagnosing wide complex tachycardia. An interval of less than or equal to 50 ms from the onset of the QRS complex to the predominant peak (or nadir) indicated supraventricular tachycardia; an interval of greater than or equal to 70 ms indicated ventricular tachycardia. The QRS complexes in leads MCL1 and MCL6 were comparable to those in leads V1 and V6 during sinus rhythm. Significant discrepancies in QRS configuration occurred between the modified and conventional precordial leads during ventricular tachycardia, especially between leads MCL1 and V1; however. these differences did not affect diagnostic accuracy. A single MCL1, V1, MCL6 or V6 lead was equally valuable in the diagnosis of wide complex tachycardia and far superior to a single lead II. A combination of leads (MCL1 + MCL6), (V1 + V6), (V1 + I + aVF) or (V1 + V6 + I + aVF) was superior to a single lead or the routinely monitored lead V1 + II combination.
为比较改良胸前导联MCL1和MCL6与传统胸前导联V1和V6，并评估所选导联用于床边连续心电图（ECG）监测的诊断准确性，在心脏电生理研究期间从92例患者记录了121次宽QRS波群心动过速。根据心内记录确定，86次心动过速为室性，35次为伴有差异性传导的室上性。MCL6或V6导联中主要QRS波偏转的早期或晚期峰值对诊断宽QRS波群心动过速很有价值。从QRS波群起始到主要峰值（或最低点）的间期小于或等于50毫秒提示室上性心动过速；间期大于或等于70毫秒提示室性心动过速。窦性心律时MCL1和MCL6导联的QRS波群与V1和V6导联的相似。室性心动过速时改良胸前导联与传统胸前导联之间的QRS形态存在显著差异，尤其是MCL1和V1导联之间；然而，这些差异并不影响诊断准确性。单独的MCL1、V1、MCL6或V6导联在诊断宽QRS波群心动过速方面同样有价值，且远优于单独的II导联。导联组合（MCL1 + MCL6）、（V1 + V6）、（V1 + I + aVF）或（V1 + V6 + I + aVF）优于单独一个导联或常规监测的导联V1 + II组合。
