[Results of using the dosing Valsalva-Weber test to determine autonomic disorders in patients with vasovagal syncope]

To estimate the value of the dosing Valsalva-Weber test (VWT) in the diagnosis of autonomic disorders in patients with vasovagal syncope (VVS).

The dosing VWT using a specialized Task Force Monitor unit ("CNSystem", Austria) with synchronous noninvasive ECG and blood pressure (BP) monitoring was carried out in 30 patients (mean age 32 ± 14 years) with VVS and 12 healthy individuals (31 ± 7 years). The analysis of the test results encompassed the visual assessment of BP change curves and heart rate in different test phases and the calculation of pressure indices, Valsalva coefficient, arterial baroreflex sensitivity, and other parameters (a total of 26).

The abnormally changed form of the mean BP curve, which was characterized by that BP by the end of Phase II test failed to achieve the baseline level, was recorded in 10 (33%) patients with VVS and in none of the healthy individuals (p = 0.04). An individual analysis of the gender- and age-adjusted Valsalva coefficient revealed its reduction in 9 (30%) patients while this indicator was within the normal range in all the healthy individuals (p = 0.04).

During the dosing VWT, the signs of sympathetic insufficiency (impaired adrenergic regulation of BP) are found in 33% of the patients with VVS and those of parasympathetic insufficiency (impaired vagus regulation of cardiochronotropic function) are in 30%.