目的 探讨直立性高血压（OHT）儿童卧位与立位心电图T波和ST段振幅变化及其临床意义。方法 选取确诊为OHT患儿49例为OHT组，同期按年龄与性别匹配43例健康儿童为对照组。测量两组卧位与立位12导联心电图心率、各导联T波和ST段振幅，比较同组卧位和立位T波振幅、ST段振幅，并比较两组卧位、立位T波振幅差和ST段振幅差。结果 对照组aVR、V₁、V₄~V₆导联T波振幅立位较卧位降低（P < 0.05），V₄、V₅导联ST段振幅立位较卧位增加（P < 0.05）。OHT组Ⅱ、aVR、aVF、V₄~V₆导联T波振幅立位较卧位降低（P < 0.05），Ⅱ导联ST段振幅立位较卧位增加（P < 0.05）。OHT组Ⅱ、V₆导联立位、卧位T波振幅差较对照组增大（均P < 0.05）。V₆导联卧位、立位T波振幅差对OHT有诊断价值（P < 0.05），V₆导联T波振幅差最佳截断值为0.105 mV，灵敏度为72.10%，特异度为57.10%。结论 V₆导联卧位、立位T波振幅差对OHT儿童具有一定的诊断价值。

Objective To examine the changes in T wave and ST segment amplitude in the supine and standing electrocardiograms (ECG) of children with orthostatic hypertension (OHT) and to determine their clinical significance. Methods A total of 49 children with OHT were included in the OHT group. Forty-three age-and sex-matched healthy children were included in the control group. Heart rate and T wave and ST segment amplitude were measured in both groups. T wave amplitude and ST segment amplitude in supine ECG were compared with those in standing ECG within each group. The differences in supine vs standing T wave amplitude and ST segment amplitude were compared between the OHT and control groups. Results In the control group, T wave amplitude in leads aVR, V₁, and V₄-V₆ were significantly lower in standing ECG than in supine ECG (P < 0.05); ST segment amplitude in leads V₄ and V₅ were significantly higher in standing ECG than in supine ECG (P < 0.05). In the OHT group, T wave amplitude in leads Ⅱ, aVR, aVF, and V₄-V₆ were significantly lower in standing ECG than in supine ECG (P < 0.05); ST segment amplitude in lead Ⅱ was significantly higher in standing ECG than in supine ECG (P < 0.05). The differences in T wave amplitude in lead Ⅱ and V₆ between supine and standing ECG were significantly higher in the OHT group than in the control group (P < 0.05). Difference in T wave amplitude in lead V₆ between supine and standing ECG was a significant diagnostic marker for OHT (P < 0.05). This marker had 72.10% sensitivity and 57.10% specificity for the diagnosis of OHT at the optimal cut-off value of 0.105 mV. Conclusions Difference in T wave amplitude in lead V₆ between supine and standing ECG has certain diagnostic value for OHT.