Sheldon R, Rose S, Flanagan P, Koshman M L, Killam S
Cardiovascular Research Group, University of Calgary, Alberta, Canada.
Circulation. 1996 Mar 1;93(5):973-81. doi: 10.1161/01.cir.93.5.973.
Recent work with head-up tilt-table testing has suggested that many patients with syncope may have recurrent neurally mediated episodes of bradycardia, hypotension, or both. The purpose of this study was to determine how to identify patients at high risk of a recurrence of neuromediated syncope after a positive isoproterenol/tilt-table test.
A cohort of 101 drug-free patients in a university hospital outpatient clinic with syncope and a positive isoproterenol/tilt-table test underwent baseline assessment of demographic variables, symptomatic burden, and hemodynamic and clinical responses to tilt testing. The primary outcome measure was the time to the first recurrent syncopal spell. The actuarial probabilities of remaining syncope free after 1 and 2 years were 72% and 60%, respectively. Multivariate proportional hazards analysis demonstrated that the most powerful predictor of a recurrence of syncope was the logarithm of the number of preceding syncopal spells (P<.001). Other predictive variables included the duration of syncopal symptoms, tilt test symptomatic outcome, and trough heart rate. The probability of a recurrence of syncope also varied with the logarithm of the frequency of preceding spells (P=.008). The median frequency of pretest spells was 0.3/month; after the tilt test, the median frequency dropped approximately 90% to 0.03 per month.
The risk of a recurrence of syncope after a positive tilt-table test can be predicted with simple pretest and intratest variables.
近期有关头高位倾斜试验的研究表明，许多晕厥患者可能会反复出现神经介导的心动过缓、低血压或两者兼有的情况。本研究的目的是确定如何识别在异丙肾上腺素/倾斜试验阳性后有神经介导性晕厥复发高风险的患者。
在一所大学医院门诊，对101例无药物治疗的晕厥患者且异丙肾上腺素/倾斜试验阳性者进行了人口统计学变量、症状负担以及倾斜试验的血流动力学和临床反应的基线评估。主要结局指标是首次复发性晕厥发作的时间。1年和2年后无晕厥的精算概率分别为72%和60%。多变量比例风险分析表明，晕厥复发的最有力预测因素是既往晕厥发作次数的对数（P<0.001）。其他预测变量包括晕厥症状持续时间、倾斜试验症状结局和最低心率。晕厥复发的概率也随既往发作频率的对数而变化（P=0.008）。试验前发作的中位频率为每月0.3次；倾斜试验后，中位频率下降约90%至每月0.03次。
通过简单的试验前和试验中变量可以预测倾斜试验阳性后晕厥复发的风险。
