Severe Covid Illness with Normal Heart Rate- An Unusual Phenomenon: Findings from a Hospital Based Observational Study

Abstract

Background: Patients having severe covid-19 illness usually develop tachycardia as an integral part of systemic inflammatory response syndrome associated with this disease and presence of tachycardia has even been proposed as a prognostic marker in these patients. However, we observed that a significant proportion of patients do not develop tachycardic response. We aimed
to investigate the prevalence of this non-tachycardic response in severe covid illness and discern the possible reasons for this phenomenon.
Methods: It was an observational, prospective-design study conducted at a leading tertiary referral center of north India. Patients hospitalized with severe covid illness were recruited for this study and were divided into two cohorts: patients with a tachycardic response and those with a non-tachycardic response. Different clinical and laboratory parameters were compared between two groups.
Results: Among 120 patients with severe covid illness included in the study, only 42 patients (35%) had tachycardia at presentation while as 78 patients (65.0%) had no tachycardia. 8 patients had absolute bradycardia with a heart rate of <60 beats per minute. Univariate regression analysis of different laboratory and clinical features between the groups with and without tachycardia did not show any statistically significant results, implying that these parameters are not primarily responsible for cardiovascular response in terms of tachycardia in these patients.
Conclusion: Tachycardia may not be seen in all patients with severe covid illness despite having hypoxemia and clinicians need to be aware of this phenomenon.