key: cord-0815015-b28ob5az
authors: Yan, Gabriel; Ang, Alicia; Tham, Sai Meng; Ng, Alvin; Chew, Ka Lip
title: Relative Bradycardia in Patients with Mild-to-Moderate Coronavirus Disease, Japan
date: 2021-01-03
journal: Emerg Infect Dis
DOI: 10.3201/eid2701.203312
sha: 2be4c9b88b534479efffe81e39ed215cc0428dbb
doc_id: 815015
cord_uid: b28ob5az

nan

To the Editors: Ikeuchi et al. (1) described the phenomenon of relative bradycardia in patients as an adjunct to the clinical diagnosis of mild-to-moderate coronavirus disease . Relative bradycardia is defined as an increase in pulse rate of <18 bpm for each 1°C rise in body temperature or a body temperature >38.9°C and pulse rate <120 bpm (2) . We performed a retrospective study comparing COVID-19 and influenza patients in a tertiary hospital in Singapore. Our study was reviewed and approved by the National Healthcare Group Domain Specific Review Board (reference no. 2020/00324)

We reviewed medical records of patients with COVID-19 or influenza, confirmed by reverse transcription PCR, who were treated during October 2019-April 2020. Patients on β-blockers were excluded (14 COVID-19 patients and 25 influenza patients). Eighty-six patients with COVID-19 and 74 patients with influenza were included; 73 influenza cases were influenza A and 1 influenza B. For CO-VID-19 patients, median age was 40.6 (range 18-72) years and 49/86 (57%) were male; for influenza patients, median age was 54 (range 22-85) years and 34/74 (45.9%) were male. Fourteen (16.3%) CO-VID-19 patients and 29 (39.2%) influenza patients had fever >38.9°C; only 4 (13.8%) influenza patients and 0 COVID-19 patients had pulse rates >120 bpm. Median pulse rate was 98.5 (interquartile range 94-101) bpm for COVID-19 patients and 99 (interquartile range 97-116) bpm for influenza patients. Linear regression of the peak temperature and the associated pulse rate of the patient predicted an increase in pulse rate of 11.12 (95% CI 7.65-14.60) bpm for COVID-19 patients and 9.5 (95% CI 5.86-13.14) bpm for influenza patients for each 1°C increase in body temperature.

Our data support the observations by Ikeuchi et al. (1) of relative bradycardia in COVID-19 patients. However, results from our cohort demonstrate relative bradycardia in patients with both viral illnesses, indicating that this phenomenon cannot be used to reliably distinguish COVID-19 from influenza and has limited clinical utility in patients who have acute respiratory illnesses.

Relative bradycardia in patients with mild-to-moderate coronavirus disease

The diagnostic significance of relative bradycardia in infectious disease