Steinberg J S, Prystowsky E, Freedman R A, Moreno F, Katz R, Kron J, Regan A, Sciacca R R
Department of Medicine, St. Luke's Roosevelt Hospital Center, New York, New York 10025.
J Am Coll Cardiol. 1994 Jan;23(1):99-106. doi: 10.1016/0735-1097(94)90507-x.
The purpose of this study was to determine the predictors of electrically induced ventricular tachycardia in a large sample of patients with unexplained syncope and to examine the value of the signal-averaged electrocardiogram (ECG) in those patient subsets with varying pretest probability of ventricular tachycardia.
In patients with unexplained syncope, electrophysiologic study can provide important diagnostic information, such as inducibility of ventricular tachycardia. The signal-averaged ECG can predict inducible ventricular tachycardia, but its utility has not been prospectively studied in a large group of patients with unexplained syncope.
At six hospitals, 189 consecutive patients with unexplained syncope underwent signal-averaged ECG and electrophysiologic studies.
Ventricular tachycardia was induced in 28 patients (15%). Univariate predictors of ventricular tachycardia included history of previous myocardial infarction, reduced left ventricular ejection fraction and abnormal signal-averaged ECG results. The signal-averaged ECG was the most sensitive test but had poor specificity. By multivariate analysis, the signal-averaged ECG and history of previous myocardial infarction were independently predictive. The risk of ventricular tachycardia increased 17-fold in patients with a previous myocardial infarction who also had an abnormal signal-averaged ECG. In patients with no history of previous myocardial infarction, no additional testing was useful in identifying those at risk for inducible ventricular tachycardia.
The signal-averaged ECG was the most sensitive noninvasive test available to predict sustained ventricular tachycardia at electrophysiologic study but was false positive in many patients. A history of previous myocardial infarction followed by the signal-averaged ECG was the most efficient screening process for predicting electrically induced ventricular tachycardia.
本研究旨在确定大量不明原因晕厥患者中电诱导室性心动过速的预测因素，并检验信号平均心电图（ECG）在室性心动过速不同预测试概率的患者亚组中的价值。
在不明原因晕厥患者中，电生理研究可提供重要的诊断信息，如室性心动过速的可诱导性。信号平均ECG可预测可诱导的室性心动过速，但其效用尚未在一大群不明原因晕厥患者中进行前瞻性研究。
在六家医院，189例连续的不明原因晕厥患者接受了信号平均ECG和电生理研究。
28例患者（15%）诱发出室性心动过速。室性心动过速的单变量预测因素包括既往心肌梗死病史、左心室射血分数降低和信号平均ECG结果异常。信号平均ECG是最敏感的检查，但特异性较差。通过多变量分析，信号平均ECG和既往心肌梗死病史具有独立预测性。既往有心肌梗死且信号平均ECG异常的患者，室性心动过速风险增加17倍。在无既往心肌梗死病史的患者中，没有其他检查有助于识别有可诱导室性心动过速风险的患者。
信号平均ECG是预测电生理研究中持续性室性心动过速最敏感的无创检查，但在许多患者中为假阳性。既往心肌梗死病史加上信号平均ECG是预测电诱导室性心动过速最有效的筛查方法。
