异丙肾上腺素直立倾斜试验的重复性

Day to day reproducibility of isoproterenol head up tilt table test

为观察直立倾斜试验（ＴＴＴ）的重复性如何？对５７例不明原因晕厥患者（研究组）和１３例健康人（对照组）采用基础倾斜试验（ＢＴＴＴ）＋异丙肾上腺素倾斜试验（ＩＴＴＴ）的方法，间隔２４小时分别行两次ＴＴＴ。结果显示：（１）研究组５７例，第一次ＢＴＴＴ诱发血管抑制性晕厥１３例（２２．８％），其中９例（６９．２％）次日ＢＴＴＴ仍诱发血管抑制性晕厥；ＴＴＴ阴性４４例，次日４２例仍ＴＴＴ阴性（９５．５％）。ＢＴＴＴ＋ＩＴＴＴ分别诱发血管抑制性晕厥２９例（５０．９％）、体位性低血压７例（１２．３％），次日仍可诱发相同表现者分别为２２例（７５．９％）和４例（５７．１％）；ＴＴＴ阴性２１例，次日１７例仍阴性（８１．０％）。两次均ＴＴＴ阳性者病史中曾经发生晕厥平均１０．０±１６．０次；第一次检查阳性，第二次阴性者为２．８±２．３次，差异有显著性（Ｐ＜０．０５）。（２）对照组１３例，１例ＩＴＴＴ诱发血管抑制性晕厥，不能重复。提示ＴＴＴ阳性者重复性稍差，合用异丙肾上腺素虽不使血管抑制性晕厥者隔日重复性降低，但体位性低血压诱发率明显增加，用于评价疗效需慎重。

To evaluate the day to day reproducibility of isoproterenol head up tilt table test, 57 patients with unexplained syncope (group A) and 13 normal controls (group B) were prospectively tested on two consecutive days. Methods: Patients were tilted to 70 degrees for 30 minutes (BTTT). If syncope or presyncope was not induced, isoproterenol infusion was employed (ITTT) for another 30 min utes or till syncope or presyncope occured. The test was repeated the next day. Results: (1) Group A: Vasodepressor syncope (VD) was induced in 13 of 57 patients (22.8%) during BTTT and 9 (69.2%) was reproducible on the second day. BTTT was negative in 44 patients and 95.5% (42/44) was also negative the second day. During BTTT+ITTT, 29 of 57 patients (50.9%) had VD response, 7 of 57 patients (12.3%) had postural hypotension (PH) response. The reproducibility was 81.0% (17/21), 75.9% (22/29) and 57.1% (4/7), respectively, as for patients with normal, VD and PH response the next day. The preceeding episodes of syncope was 10.0±16.0 in patients with both positive TTTs and 2.8±2.3 in those with first TTT positive and second TTT negative results ( P <0 05). (2) Group B:One control was ITTT positive and could not be reproduced the second day. These data showed that the use of isoproterenol may not decrease the reproducibility of TTT. But the variability of the positive TTT may limit the use of TTT for evaluation of therapy.