637 PREVALENCE AND CLINICAL SIGNIFICANCE OF RELATIVE BRADYCARDIA IN COVID-19 INPATIENTS

Abstract

Abstract Background and aims Relative Bradycardia (RB) is a poorly understood condition that refers to inappropriately low heart rate response to a given increase in body temperature. Dysfunctional crosstalk between the immune system and the autonomous nervous system has been advocated. It is most often observed in intracellular gram negative and parasitic infections, with a prevalence ranging between 15% and 20%. The aim of this study was to identify the prevalence, clinical determinants and significance of RB in patients hospitalized for SARS-CoV-2 infection and to evaluate its prognostic value for long-covid syndrome during follow-up. Methods We enrolled consecutive patients hospitalized for SARS-CoV-2 infection from March 2020 to April 2021. We collected clinical parameters including clinostatic and orthostatic blood pressure (BP) and heart rate (HR) at 1,3 and 5 minutes, oxygen saturation, body temperature (BT), routine blood tests, 12-lead ECG, and 48-h Holter ECG. At follow up, clinical symptoms were investigated by novel Malmo POTS Symptoms (MAPS) questionnaire. Results Total population included 269 inpatients (mean age 67±17 years, 59% male).Of these, 30 (11%) presented with sinus bradycardia and 37 (14%) RB. RB was more frequently observed in younger male patients with higher BT and heightened CRP levels. There were no significant correlations between BP and HR orthostatic changes and BR during hospital admission or during follow-up. No clinically relevant arrhythmias were revealed during 48-hour ECG monitoring. After mean16-month follow-up, MAPS score was higher in patients with RB (30±19) compared to those without RB (18±21, p=0.001) during index hospital admission. Dizziness, palpitations and fatigue were more frequently reported in patients with RB(p<0.001). Conclusions RB is not an uncommon condition during acute COVID-19. SARS-CoV-2 inpatients who presented RB during index hospitalization showed a higher symptom burden during follow-up, as recorded by MAPS score. Further studies are needed to clarify the clinical significance of RB and its value to predict post-acute sequelae of COVID-19. Spahic et Al., Malmö POTS symptom score: Assessing symptom burden in postural orthostatic tachycardia syndrome JIM 2022 (in press)