From the Guidelines
Diagnosing Postural Orthostatic Tachycardia Syndrome (POTS) requires a comprehensive approach involving both clinical evaluation and specific testing, with the primary diagnostic test being the tilt table test or active stand test, where heart rate and blood pressure are monitored while changing from lying to standing position, as recommended by the 2018 ESC guidelines for the diagnosis and management of syncope 1.
Diagnostic Criteria
The diagnosis of POTS is typically confirmed when there's an increase in heart rate of at least 30 beats per minute (or ≥40 bpm for those aged 12-19) within 10 minutes of standing, without a significant drop in blood pressure, as defined in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1.
Pre-Testing Preparations
Before testing, patients should stop medications that might affect results, such as beta-blockers or stimulants, for 48-72 hours under medical supervision, and proper hydration is important before testing, but caffeine should be avoided, as suggested by the practical instructions for the 2018 ESC guidelines for the diagnosis and management of syncope 1.
Additional Diagnostic Tools
Additional diagnostic tools include:
- A detailed medical history focusing on symptoms like dizziness, fatigue, and heart palpitations upon standing
- A physical examination
- Blood tests to rule out other conditions
- Sometimes a 24-hour Holter monitor to track heart rhythm, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1.
Specialized Evaluation
POTS is often misdiagnosed because its symptoms overlap with anxiety disorders or chronic fatigue, so specialized evaluation by a cardiologist, neurologist, or dysautonomia specialist is recommended for accurate diagnosis, as suggested by the practical instructions for the 2018 ESC guidelines for the diagnosis and management of syncope 1.
From the Research
Diagnostic Approach
To diagnose Postural Orthostatic Tachycardia Syndrome (POTS), the following steps can be taken:
- A detailed medical history to identify the mechanism of symptom onset, clinical features, and associated conditions 2
- A physical examination with orthostatic vital signs or a brief tilt table test, and a resting 12-lead electrocardiogram to detect excessive tachycardia upon standing 3
- Laboratory testing to exclude mimics of autonomic dysfunction and recognize conditions that may exacerbate symptoms 2
- Autonomic testing to confirm a POTS diagnosis, exclude other causes of orthostatic intolerance, and characterize POTS into neuropathic and hyperadrenergic subtypes 2
Diagnostic Criteria
The diagnostic criteria for POTS include:
- Sustained excessive tachycardia upon standing in the absence of significant orthostatic hypotension and other medical conditions or medications 3
- Chronic symptoms of orthostatic intolerance, such as fatigue, exercise intolerance, and gastrointestinal distress 4
- A typical patient with POTS is a female of child-bearing age, who often first displays symptoms in adolescence 4
Additional Diagnostic Testing
Additional diagnostic testing may be warranted in selected patients based on clinical signs, including:
- Epidermal skin punch biopsy 2
- Exercise testing 2
- Radiographic studies 2
- Sleep studies 2
- Gastrointestinal motility studies 2
- Urodynamic studies 2
Importance of Accurate Diagnosis
Accurate diagnosis of POTS is crucial to exclude conditions that could cause or mimic the syndrome, and to identify co-morbid conditions 4. A thorough diagnostic approach can help establish the diagnosis and guide management.