Kapoor W N, Smith M A, Miller N L
Department of Medicine, University of Pittsburgh, Pennsylvania.
Am J Med. 1994 Jul;97(1):78-88. doi: 10.1016/0002-9343(94)90051-5.
Upright tilt testing is widely utilized for the evaluation of syncope. Recently, there have been concerns about the specificity and the lack of standard methodology for this test. The purpose of this study was to summarize the methodologies of upright tilt testing in patients with syncope of unknown origin, the responses in control subjects, and the reproducibility and selection of therapy.
We used MEDLINE to search English language articles from 1966 to June 30, 1992. Studies were included for content review if they met our inclusion criteria. Data were extracted from each article by two trained reviewers using a predesigned data collection instrument.
Thirty-three articles were included for review. There was considerable variability in the methodologies of tilt testing. Overall positive responses were reported in 49% of patients in passive-only studies as compared with 66% of patients in studies using isoproterenol with tilt testing. The percentage of positive responses increased with increasing angle of testing for studies using isoproterenol. There was no relationship between the percentage of positive responses and the maximum dose of isoproterenol. When we compared the results of passive studies that tested patients for 60 minutes at 60 degrees with the results of isoproterenol studies that tested patients at 60 degrees, the positive rate for passive-only studies was 54% as compared with 52% for the isoproterenol studies. The percentage of positive response in control subjects with passive studies was 8.9% (range 0% to 100%), and with isoproterenol 27% (range 0% to 65%). Other groups of patients showed a wide range of positive responses (range 0% to 83%). Reproducibility ranged from 71% to 87%. Upon retesting while the patient was receiving therapy, 90% of 115 positive patients were negative. Eighty-nine percent of 105 positive patients who were receiving therapy and followed for a mean time of 12 months were free of syncope.
This review strongly suggests that isoproterenol may not have an effect on stimulating vasovagal syncope during upright tilt testing. We recommend protocols of passive tilt testing procedures at 60 degrees for 45 to 60 minutes since the overall specificity is higher with this method. The use of isoproterenol during tilt testing adds to the cost and complexity of the test, is associated with a higher rate of false-positive responses, leads to potential complications, and, thus, should be avoided.
直立倾斜试验广泛用于晕厥的评估。最近，人们对该试验的特异性及缺乏标准方法表示担忧。本研究的目的是总结不明原因晕厥患者直立倾斜试验的方法、对照受试者的反应、试验的可重复性及治疗选择。
我们使用MEDLINE检索1966年至1992年6月30日的英文文章。符合纳入标准的研究纳入内容综述。由两名经过培训的审阅者使用预先设计的数据收集工具从每篇文章中提取数据。
纳入33篇文章进行综述。倾斜试验方法存在很大差异。仅采用被动倾斜试验的研究中，49%的患者有总体阳性反应，而使用异丙肾上腺素联合倾斜试验的研究中这一比例为66%。在使用异丙肾上腺素的研究中，阳性反应百分比随试验角度增加而升高。阳性反应百分比与异丙肾上腺素最大剂量之间无关联。当我们将在60度下对患者进行60分钟测试的被动试验结果与在60度下对患者进行测试的异丙肾上腺素试验结果进行比较时，仅被动试验的阳性率为54%，而异丙肾上腺素试验为52%。被动试验中对照受试者的阳性反应百分比为8.9%（范围0%至100%），使用异丙肾上腺素时为27%（范围0%至65%）。其他患者组的阳性反应范围很广（范围0%至83%）。可重复性范围为71%至87%。在患者接受治疗期间再次测试时，115名阳性患者中有90%变为阴性。105名接受治疗且平均随访12个月的阳性患者中，89%未再发生晕厥。
本综述强烈提示，在直立倾斜试验期间异丙肾上腺素可能对刺激血管迷走性晕厥无作用。我们推荐采用60度被动倾斜试验程序45至60分钟的方案，因为该方法总体特异性更高。倾斜试验期间使用异丙肾上腺素会增加试验成本和复杂性，与更高的假阳性反应率相关，会导致潜在并发症，因此应避免使用。
