Long COVID clinics should assess patients whose symptoms worsen upright and improve with sitting or lying down for postural orthostatic tachycardia syndrome and other causes of orthostatic intolerance. Bedside standing or leaning tests can help separate POTS from orthostatic hypotension, which symptoms alone cannot do.

Why It Matters To Your Practice

• In a study of 277 patients across eight UK long COVID clinics, 52% reported symptoms during lean testing, 7% met the study’s test-based definition of POTS, and 8% met its definition of orthostatic hypotension.

• About half of patients with either test finding had not reported typical orthostatic symptoms beforehand, suggesting symptom-based case finding may miss some patients in specialist long COVID settings when testing is feasible more broadly than symptom-triggered screening alone.

Clinical Implications

• A practical approach is supine heart rate and blood pressure measurement after 5 to 10 minutes of rest, followed by repeat measurements and symptom recording through 10 minutes of quiet standing or supported leaning, stopping if the patient cannot safely continue.

• POTS requires a sustained heart-rate increase of at least 30 beats per minute within 10 minutes upright, or at least 40 beats per minute at ages 12 to 19, without significant sustained orthostatic hypotension, plus frequent upright symptoms improving with recumbency for at least 3 months and no better alternative explanation for sinus tachycardia, according to a CMAJ review on diagnosis and management of POTS in 2022 (PMC8920526). Additional testing should be guided by findings rather than ordered routinely for everyone, and rehabilitation should be individualized with attention to post-exertional symptom exacerbation, exertional desaturation, and possible cardiac impairment before exercise training.

Insights

• POTS and orthostatic hypotension can both cause dizziness, presyncope, fatigue, and cognitive symptoms while upright, but orthostatic hypotension is defined by a sustained blood-pressure fall and can still include a substantial compensatory heart-rate rise, especially with volume depletion.

• POTS is a heterogeneous syndrome rather than a single mechanism. Proposed contributors include reduced venous return or circulating volume, partial autonomic dysfunction, heightened sympathetic activity, reduced activity, and possible post-COVID immune, vascular, or autonomic changes, but no single mechanism or validated immune biomarker establishes the diagnosis in an individual patient. Small studies have also reported altered cerebral blood flow measures and low carbon dioxide during upright testing in long COVID, but these findings do not establish POTS or explain every patient’s symptoms.

The Bottom Line

• Screening orthostatic-intolerance patients in long COVID clinics for POTS is supported when bedside testing is available, but clinicians should evaluate for orthostatic hypotension and other causes at the same time rather than equating upright symptoms with POTS.

• Test results need clinical context, including medications, volume status, rhythm, and other systemic or cardiopulmonary causes, and evidence for treating specifically post-COVID POTS remains limited.

References:

Long COVID and Cholesterol: Can COVID Change Your Levels?

Coronavirus Disease 2019 is an Occupational Disease for Teachers: How to Support the Teacher Workforce

Postural tachycardia syndrome and long COVID: an update