Autonomic dysfunction in COVID-19 patients receiving mechanical ventilation: A cross-sectional study

Abstract

BACKGROUND: Coronavirus disease 2019 (COVID-19) can damage cardiac tissue by increasing troponin levels and inducing arrhythmias, myocarditis, and acute coronary syndrome. OBJECTIVES: To analyze the impact of COVID-19 on cardiac autonomic control in mechanically ventilated intensive care unit (ICU) patients. DESIGN AND SETTING: This cross-sectional analytical study of ICU patients of both sexes receiving mechanical ventilation was conducted in a tertiary hospital. METHODS: Patients were divided into COVID-19-positive (COVID(+)) and COVID-19-negative (COVID(-)) groups. Clinical data were collected and heart rate variability (HRV) records obtained using a heart rate monitor. RESULTS:The study sample comprised 82 subjects: 36 (44%) in the COVID(-) group (58.3% female; median age, 64.5 years) and 46 (56%) in the COVID(+) group (39.1% females; median age, 57.5 years). The HRV indices were lower than the reference values. An intergroup comparison identified no statistically significant differences in the mean normal-to-normal (NN) interval, standard deviation of the NN interval, or root mean square of successive differences in NN intervals. The COVID(+) group had an increased low frequency (P = 0.05), reduced high frequency (P = 0.045), and increased low frequency/high frequency (LF/HF) ratio (P = 0.048). There was a weak positive correlation between LF/HF and length of stay in the COVID(+) group. CONCLUSION: Patients who received mechanical ventilation had lower overall HRV indices. COVID(+) patients who received mechanical ventilation had lower vagal HRV components. These findings likely indicate clinical applicability, as autonomic control impairments are associated with a greater risk of cardiac death.

Autonomic Function and Baroreflex Control in COVID-19 Patients Admitted to the Intensive Care Unit

“…We suggest that SURVs within the COVID-19 group might have more powerful internal regulatory resources to limit the progress of inflammation, prevent exaggerated immune responses and avoid the development of arrhythmic events [1,8,11,12,22,49,51]. The more limited activity of the cardiac arm of the baroreflex might contribute to the worse prognosis associated with small HP variations in critically ill COVID-19 patients [1,7,8,19,20].…”

“…Modifications of the autonomic control and baroreflex function following COVID-19 infection have often been studied via the analysis of spontaneous changes in heart period (HP) and systolic arterial pressure (SAP) [17,18]. Remarkably, it was found that the magnitude of HP changes holds prognostic value in critically ill COVID-19 patients [1,7,8,19,20]. Lower values of HP variability were associated with the severity of COVID-19 [19], while higher values were a distinctive feature of surviving COVID-19 patients admitted to the ICU [1].…”

“…Lower values of HP variability were associated with the severity of COVID-19 [19], while higher values were a distinctive feature of surviving COVID-19 patients admitted to the ICU [1]. Moreover, smaller changes in HP were reported to precede the increase in inflammatory markers [7], to predict ICU indication and admission in the first week after hospitalization [8] and to characterize patients who received mechanical ventilation [20]. Survivors of mild COVID-19 at 3-6 months exhibited an impaired baroreflex response that might explain the incidence of postural hypotensive episodes in post-COVID-19 patients [17].…”