Syncope at SARS-CoV-2 onset due to impaired baroreflex response

Abstract We describe clinical and laboratory findings in 35 consecutive patients tested positive for SARS-CoV-2 by reverse transcriptase-polymerase chain reaction on nasopharyngeal swab that presented one or multiple syncopal events at disease onset. Neurological examination and electrocardiographic findings were normal. Chest computed tomography showed findings consistent with interstitial pneumonia. Arterial blood gas analysis showed low pO2, pCO2, and P/F ratio indicating hypocapnic hypoxemia, while patients did not show the expected compensatory heart rate increase. Such mechanism could have led to syncope. We speculate that SARS-CoV-2 could have caused angiotensin-converting enzyme-2 (ACE2) receptor internalization in the nucleus of the solitary tract (NTS), thus altering the baroreflex response and inhibiting the compensatory tachycardia during acute hypocapnic hypoxemia.