The TILT TABLE TEST (TTT), also known as the HEAD-Up-TILT TEST (HUTT), is considered to be the “Gold Standard” (most reliable) test for diagnosing POTS. It utilizes a special table that can be gradually tilted head-end up. The test compares pulse and blood pressure when tilted upright compared to measurements during lying down prior to tilting. During tilting one is unable to squeeze one’s leg muscles, simulating the venous pooling in the lower body that occurs among individuals with POTS when standing upright. When tilted upright some with POTS experience their usual symptoms like headaches, dizziness, blurred vision and flushing. Ideally, the test is best performed in the morning and mid-menstrual cycle in females.
An increase in heart rate of greater than 40 bpm (beats per minute) in teenagers and adolescents (ages 12-19) or a rise greater than 30 bpm in adults or pulse rise equal to or greater than 120 bpm with a negligible fall in blood pressure during a gradual passive tilt (without weight-bearing) is considered a positive test for POTS.
If positive, within 10 minutes the autonomic nervous system kicks-in to speed up the heart rate and make up for the fall in cardiac output of blood to the brain. Tachycardia (rapid heart rate) is the body’s attempt to restore that all-important blood flow to the brain. Diminished blood flow to the brain is responsible for the majority of POTS-associated symptoms.
Interpretation of the TTT results should be clear cut. Requirements for a diagnosis of POTS: include:
- Tilted pulse rate rise of greater than 30 or 40 beats/min,
- Tilted heart rate exceeding 120 beats/minute
- No significant fall in blood pressure during tilting
- History of significant associated POTS symptoms
- Exclusion of other medical conditions
If a significant drop in blood pressure occurs, with or without symptoms similar to those of POTS, then the diagnosis is postural hypotension (low blood pressure when standing), not POTS! Postural hypotension requires a completely different medical evaluation and therapeutic approach.
POWER over POTS by Scheldon Kress, M.D. provides an easy test (Easy Screening Head-Up Test) that anyone can do at home to screen for POTS. Explore additional information at POTS NEWS.