直立倾斜试验中药物假阳性反应的表现

Manifestations of drug- induced pseudopositive responses during head- up tilt test

目的 :研究直立倾斜试验中药物假阳性反应的表现。 方法 :分析 10 0例临床表现为血管迷走性晕厥患者和 2 1例无晕厥史的正常人直立倾斜试验的结果。 结果 :药物反应主要表现为 :1缓慢发展的血压下降 ,伴随代偿性心率增加 ;2长时间明显血压下降可出现轻微心动过缓 ,但心率减慢 <同阶段的 30 % ;3逐渐出现的症状如头晕、眼花、出汗等晕厥先兆与平时发作的症状不一样。排除药物反应后试验的敏感性为 62 % ,特异性为 90 .5% ,阳性反应者无一例心率≥150次 / min。 结论 :正确区别突发的迷走神经反射和药物反应 ,并且在试验过程中设置 150次 /min的心率上限 。

Objectives:To study the manifestations of drug- induced pseudopositive re- sponses during head- up tilttest(HUT) .Methods:To analyze the data of HUT from 1 0 0 pa- tients with symptoms of vasovagal syncope clinically and2 1 normal controls with no histories of syncope. Results:The main manifestations of drug- induced pseudopositive responses were:1 Progressive but slow decrease in systolic blood pressure with concomitant compen- satory tachycadia;2 Only slight bradycardia after a prolonged period of marked hypoten- sion;3 Gradual development of symptoms such as dizziness,blurred vision,fatigue and per- spiration,sometimes followed by presyncope similar to the spontaneous ones and not recog- nized by the patients.After excluding the drug- induced pseudopositive responses,the sensi- tivity of HUT was6 2 % ,specificity was90 .5 % .Heartrate in patients with positive response never exceeded1 5 0 beats/min. Conclusions:Correct differentiation between sudden vagal neural reflex and drug- induced pseudopositive response and taking 1 5 0 heart beats/min as the upper limit are effective ways to increase the sensitivity of HUT without decreasing its specificity.