Adrenocortical response during HUT test in patients with vasovagal syncope

This prospective observational study was carried out to evaluate the response of adrenocortical hormones (cortisol and aldosterone) to head-up tilt (HUT)-induced vasovagal syncope in relation to hemodynamic changes.

Blood samples from 79 patients (48 women and 31 men, age 19-73 years) who underwent the HUT test were analyzed for serum aldosterone and cortisol. On the basis of their response, patients were categorized into two groups: 50 HUT-positive (HUT+) and 29 HUT-negative (HUT-) patients.

HUT+ patients exhibited significantly lower baseline aldosterone levels compared with HUT- patients (203.1 ± 78.8 versus 266.2 ± 76.3 pg/ml, p = 0.0009). Similarly, aldosterone levels after the HUT test were lower in the HUT+ as compared with the HUT- group (249.5 ± 101.3 versus 351.4 ± 98.11 pg/ml, p < 0.0001). However, serum cortisol showed no significant differences between groups. Aldosterone increased in response to HUT in both groups. Aldosterone positively correlated with systolic and diastolic blood pressure, as well as heart rate. Integration of aldosterone with clinical assessment and additional laboratory tests may improve diagnostic accuracy and risk stratification.

The results demonstrate significantly lower serum aldosterone concentrations in HUT+ patients at baseline and after HUT test in comparison with HUT- patients. Moreover, aldosterone levels positively correlated with systolic and diastolic blood pressure (BP). However, serum cortisol levels did not discriminate HUT+ from HUT- patients.