Background: Orthostatic intolerance (OI) is a common clinical
symptom in dizziness clinic. The head-up tilt table test (HUT) is
one of the primary clinical examination for evaluating OI. There
is no consensus on the optimum method for diagnosis of
orthostatic hypotension (OH). Herein, we performed the additional
squat combined with blood pressure (BP) monitoring for OI
patients with normal HUT.

Methods: The study included 32 consecutive patients with
orthostatic intolerance for 3 months since April, 2018 (Period I)
and 27 patients with orthostatic intolerance for 3 months since
April, 2019 (Period II) in dizziness clinic of Chungnam National
University Hospital. During Period II, the additional squat
combined with BP test was performed for normal HUT results in
patients with OI. In squat combined orthostatic BP measurement,
the first BP measurement was taken following 3 minutes of rest at
the squat position; afterwards the patients were raised upright
and the measurement was monitored for 2 minutes, using a
continuous beat-to-beat BP monitoring.

Results: In this study, there was significant difference in OH
diagnosis (p<0.001); 40.6% (13/32) by conventional HUT (Period I)
vs. 92.5% (25/33) by conventional HUT and additional squat test
for normal HUT (Period II). In patients with normal HUT, the
positive OH was 86.7% (13/15) by the additional squat combined BP
measurement (Period II).

Conclusions: In addition to HUT, squat test combined with BP
measurement might be more informative for understanding and
diagnosing the OH, particularly in patients with OI and normal
HUT in dizziness clinic.

KEYWORDS : Orthostatic intolerance, Tilt table test