The infection caused by the SARS-CoV-2 continues affecting millions of people worldwide and vaccines to prevent the coronavirus disease (COVID-19) are considered the most promising approach for curbing the pandemic. Otherwise, cardiovascular and neurological complications associated with the vaccines were speculated and some few case reports were published. We describe a case of postural orthostatic tachycardia syndrome (POTS) after viral vector COVID-19 vaccination and the possible autoimmune process of the syndrome. A 35-year-old female, without previous symptoms or comorbidities, developed intermittent palpitation, intense fatigue and dyspnea, compromising her daily activities, triggered by upright position, seven days following the second dose of the Oxford vaccine. Physical examination was normal, except for a heart rate (HR) increase of 33 beats/min from supine to standing position, with no significant change in blood pressure and reproduction of symptoms. A 24-hour Holter monitoring revealed episodes of spontaneous sinus tachycardia correlated with palpitation and fatigue. Extensive diagnostic investigations excluded primary cardiac, endocrine, infectious and rheumatologic etiologies. The patient underwent an autonomic function test which demonstrated normal baroreflex sensitivity, as well as normal cardiovagal and adrenergic scores. Head-up tilt test showed persistent orthostatic tachycardia (HR increase from a medium of 84 beats/min in supine position to 126 beats/min during upright tilt), without hypotension, consistent with the diagnostic criteria for POTS. According to the current guidelines, general behavior recommendations, pharmacotherapy with low dose of propranolol associated with the autonomic rehabilitation were oriented. Along three months of follow-up, the patient reported a gradually improvement in her symptoms. POTS is a heterogeneous disorder of the autonomic nervous system characterized by orthostatic tachycardia associated with symptoms of orthostatic intolerance. Although the physiopathology of COVID-19 vaccine and autonomic disorders remains speculative, autoimmune response is one of the possible mechanisms. Based on clinic presentation, the time frame of symptom onset is consistent with other well-known post-vaccination syndromes, which may be an indicator of an autoimmune process induced by immunization. Further studies are needed to assess causal relationship between immunization and autonomic dysfunction.
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