2021 Volume 80 Issue 3 Pages 159-166
Orthostatic tests, which include an active orthostatic test and a passive orthostatic test, are effective tests for differentiating among causes of orthostatic intolerance, such as orthostatic hypotension (OH), postural orthostatic tachycardia syndrome (POTS), and vasovagal syncope (VVS). OH is diagnosed when the systolic blood pressure (SBP) decreases by more than 20mmHg and/or the diastolic blood pressure (DBP) decreases by more than 10mmHg as soon as the patient stands, based on the criteria of the International Autonomic Nervous Society. The passive orthostatic test has a higher sensitivity for the diagnosis of OH as compared to the active orthostatic test. On the other hand, in cases where the blood pressure decreases are seen at 3 minutes or after, the diagnosis of VVS should be considered. POTS is diagnosed if the heart rate increases by more than 30 bpm when the patient stands, in the absence of OH. Orthostatic tests are useful to understand the underlying condition in patients suffering from orthostatic dizziness and chronic dizziness.
