Autonomic Dysfunction in Postural Orthostatic Tachycardia Syndrome (POTS): A Neurocardiological Perspective

Abstract

Postural Orthostatic Tachycardia Syndrome (POTS) is an autonomic nervous system disorder characterised by an abnormal rise in heart rate, usually about 30 beats per minute or greater, in 10 minutes of standing, and without a decrease in blood pressure. It manifests itself with a variety of symptoms, including palpitations, dizziness, fatigue, gastrointestinal discomfort, and the so-called brain fog, which significantly affects everyday life. Traditionally, POTS has been divided into neuropathic, hypovolemic and hyperadrenergic forms depending on the underlying causes, although recent research indicates that the condition is more complicated. Autoimmune activity, neurohumoral imbalance like the renin-aldosterone paradox, and brain involvement, especially of the autonomic control, are now being identified as important factors. The rise in post-COVID-19 POTS cases highlights the need to understand these mechanisms, with up to 14% of COVID survivors developing POTS-like symptoms. This literature review is a critical analysis of the literature on POTS, autonomic dysfunction, brain-heart axis, and related diagnostic and treatment methods. According to the search of PubMed, Google Scholar, Scopus, Science Direct, and Web of Science, the publications of 2015-2025, the following key findings can be identified: a repetitive pathophysiology with sympathetic denervation, low blood volume, and excessive sympathetic activity, and neuroimaging showing cerebral hypoperfusion. This reduced blood flow may explain the mental cloudiness patients experience. Diagnosis is suggested to be made using such tools as tilt-table testing, heart rate variability analysis, and triple ECG tests, but there is still no single conclusive test. Lifestyle changes, typically including regular exercise, salt and fluid supplementation, and compression garments, are normally the first line of management and have demonstrated considerable improvement, even remission. Pharmacological therapy, such as beta-blockers, ivabradine, and pyridostigmine, is specific to the symptoms. And more sophisticated interventions, such as vagus nerve stimulation and hybrid ablation, are promising yet needs research. In conclusion, POTS still remains a multifaceted condition that needs personalised care and a multidisciplinary approach. While treatments are improving, more research is needed to refine diagnostic tools, explore novel therapies, and understand long-term outcomes, especially for those whose symptoms emerged after COVID-19.