Lewis D A, Zlotocha J, Henke L, Dhala A
Department of Pediatrics, Medical College of Wisconsin-Children's Hospital of Wisconsin, USA.
J Am Coll Cardiol. 1997 Oct;30(4):1057-60. doi: 10.1016/s0735-1097(97)00255-6.
This study sought to determine the specificity of commonly used tilt protocols in children.
Tilt table testing is commonly utilized in the evaluation of children and adolescents with syncope despite a lack of uniformity in tilt protocols and a lack of studies of specificity in normal control subjects.
Sixty-nine normal control volunteers (12 to 18 years old, 38 male, 31 female) with no previous history of syncope, presyncope or arrhythmia underwent tilting to 80 degrees, 70 degrees or 60 degrees for a maximum of 30 min on a motorized table with a footboard support. Autonomic maneuvers, including deep breathing, carotid massage, Valsalva maneuver and diving reflex, were performed before tilt testing to determine whether the response to these maneuvers could identify subjects prone to fainting during tilt testing.
Symptoms of presyncope and frank syncope were elicited in 24 of 69 subjects (13 male, 11 female): 6 (60%) of 10 were tilted at 80 degrees, 9 (29%) of 31 at 70 degrees and 9 (32%) of 28 at 60 degrees. Tilt testing at 80 degrees was terminated after the tenth subject by the institutional review board. The mean time to a positive test response was 10.5 min at 80 degrees, 14.2 min at 70 degrees and 13.2 min at 60 degrees. In the 80 degrees tilt, 4 of 10 subjects had a positive response within 10 minutes, whereas only 3 of 31 and 2 of 28 had a positive response within < 10 min at 70 degrees and 60 degrees tilt angles, respectively. Subjects with and without a positive response to tilt testing were similar with respect to age; gender; PR, QRS and QT intervals; and baseline heart rate and blood pressure. Likewise, responses to other autonomic function tests performed were similar in tilt-positive and tilt-negative patients. The power for detecting a significant difference between patients tilted at 80 degrees versus 60 degrees and 70 degrees was 0.45 and for detecting differences in autonomic tone between tilt-positive (n = 24) and tilt-negative (n = 45) subjects was 0.8.
Children appear to be more susceptible to orthostatic stress than adults. Therefore, tilt protocols commonly used in adults lack specificity in teenage patients. A specificity > 85% may be obtained by performing the tilt test at 60 degrees or 70 degrees for no longer than 10 min.
本研究旨在确定儿童常用倾斜试验方案的特异性。
尽管倾斜试验方案缺乏一致性，且缺乏对正常对照受试者特异性的研究，但倾斜试验仍常用于评估患有晕厥的儿童和青少年。
69名无晕厥、先兆晕厥或心律失常病史的正常对照志愿者（年龄12至18岁，男性38名，女性31名）在带有踏板支撑的电动倾斜台上倾斜至80度、70度或60度，最长持续30分钟。在倾斜试验前进行自主神经动作，包括深呼吸、颈动脉按摩、瓦尔萨尔瓦动作和潜水反射，以确定对这些动作的反应是否能识别出在倾斜试验中容易昏厥的受试者。
69名受试者中有24名（男性13名，女性11名）出现先兆晕厥和明显晕厥症状：10名倾斜至80度的受试者中有6名（60%），31名倾斜至70度的受试者中有9名（29%），28名倾斜至60度的受试者中有9名（32%）。机构审查委员会在第10名受试者后终止了80度倾斜试验。80度倾斜试验阳性反应的平均时间为10.5分钟，70度为14.2分钟，60度为13.2分钟。在80度倾斜试验中，10名受试者中有4名在10分钟内出现阳性反应，而在70度和60度倾斜试验中，31名受试者中分别只有3名和28名受试者中有2名在<10分钟内出现阳性反应。倾斜试验阳性和阴性的受试者在年龄、性别、PR间期、QRS间期和QT间期以及基线心率和血压方面相似。同样，倾斜试验阳性和阴性患者对其他自主神经功能测试的反应也相似。检测80度倾斜与60度和70度倾斜患者之间显著差异的效能为0.45，检测倾斜试验阳性（n = 24）和阴性（n = 45）受试者之间自主神经张力差异的效能为0.8。
儿童似乎比成人更容易受到直立位应激的影响。因此，成人常用的倾斜试验方案在青少年患者中缺乏特异性。通过在60度或70度进行倾斜试验不超过10分钟，可能获得大于85%的特异性。
