From the Guidelines
Diagnosing POTS requires a combination of clinical evaluation and specific testing, with a primary diagnostic test being a standing test or tilt table test, where heart rate and blood pressure are measured while changing from lying to standing position, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. The diagnostic process usually begins with a thorough medical history focusing on symptoms like lightheadedness, fatigue, brain fog, and palpitations that worsen when upright. Key points to consider in the diagnosis of POTS include:
- Frequent symptoms that occur with standing, such as lightheadedness, palpitations, tremulousness, generalized weakness, blurred vision, exercise intolerance, and fatigue
- An increase in heart rate of ≥30 bpm during a positional change from supine to standing (or ≥40 bpm in those 12–19 years of age)
- The absence of orthostatic hypotension (>20 mm Hg reduction in systolic BP)
- Symptoms must persist for at least 3-6 months to meet diagnostic criteria for POTS, as stated in the guidelines 1. Physical examination, ECG, and blood tests are often performed to rule out other conditions. Some specialists may also conduct additional autonomic function tests or a 24-hour Holter monitor to observe heart rhythm patterns. It's essential to note that POTS involves dysregulation of the autonomic nervous system, causing an exaggerated heart rate response to compensate for blood pooling in the lower body when standing, as described in the guidelines 1.
From the Research
Diagnosis of Postural Tachycardia Syndrome (POTS)
To diagnose POTS, the following methods are used:
- A detailed medical history to identify the mechanism of symptom onset, clinical features, associated clinical conditions or disorders, and factors that may result in symptom exacerbation 2
- Physical examination with orthostatic vital signs or brief tilt table test to assess for orthostatic intolerance 3
- A resting 12-lead electrocardiogram to evaluate heart rate and rhythm 3
- Autonomic testing to confirm a POTS diagnosis, exclude other causes of orthostatic intolerance, and characterize POTS into neuropathic and hyperadrenergic subtypes 2
- Laboratory testing to exclude mimics of autonomic dysfunction, recognize conditions that may exacerbate symptoms, and identify conditions that may cause or be associated with autonomic nervous system disease 2
Diagnostic Criteria
The diagnostic criteria for POTS include:
- Sustained excessive tachycardia upon standing that occurs in the absence of significant orthostatic hypotension and other medical conditions and or medications 3
- Chronic symptoms of orthostatic intolerance 3
- A heart rate increment of ≥ 30 beats/min on head-up tilt 4
Additional Diagnostic Testing
Additional diagnostic testing may be warranted in selected patients based on clinical signs, including: