ELEVATED RESTING HEART RATE AS INDEPENDENT IN-HOSPITAL PROGNOSTIC MARKER IN COVID-19

Objective: SARS-CoV-2 infection could be complicated by serious autonomic imbalance caused directly by the virus or through secondary release of inflammatory cytokines. Some studies suggested that elevated resting heart rate (HR) and resting tachycardia, being markers of an increased adrenergic cardiac drive, are associated with poor prognosis in COVID-19 syndrome. Design and method: We performed a retrospective analysis in an inpatient cohort of 389 subjects diagnosed with SARS-CoV-2 infection to investigate the prognostic relevance of HR in predicting the maximum care intensity needed during hospitalization according to the following four severity outcome classes: I) no need for oxygen support/need for low flow oxygen therapy; II) need for high flow oxygen therapy/continuous positive airway pressure; III) transfer to the Intensive Care Unit; IV) death. HR assessments were recorded on admission and during the first 3 and 7 days of hospitalization. Results: For each class increase in maximum care intensity we observed a corresponding significant increase in HR, considering both data collected on admission (average HR value: 90.1 ± 17 beats/minute, p-value trend = 0.0397), and during the first 3 days (p-value trend < 0.0006) or 7 days (p-value trend < 0.0001) of hospitalization. The significant trend was maintained after adjustment for age, sex, comorbidities and fever and in the subpopulation of patients (n = 118) not receiving drugs potentially active on HR both before and during hospitalization. Kaplan-Meier curves for survival based on HR displayed a significant decreased survival in patients with higher HR. Conclusions: The assessment of HR during hospitalization provides information on the clinical outcome of patients affected by SARS-CoV-2 infection independently of other confounders. HR as an in-hospital prognostic marker can be obtained both through a first assessment at the admission or mean values over the course of hospitalization with an increase of its accuracy by a 7-days longitudinal evaluation. Further studies might elucidate the association between SARS-CoV-2 infection with multiple autonomic abnormalities.