Heart rate variability in the medium term following COVID-19: A case–control study

Acute coronavirus disease-19 (COVID-19) infection is known to be associated with adverse cardiovascular complications. However, data on its longer-term cardiovascular effects remain limited. This case–control study aims to investigate potential medium-term cardiovascular sequelae of COVID-19. A random selection of patients who tested positive for COVID-19 through nasopharyngeal swabbing constituted the case group, while the control group comprised individuals who tested negative for both swab and COVID-19 immunoglobulin G antibodies. A total of 233 subjects were recruited, including 161 cases and 72 controls. The median age was 45 years (interquartile range [IQR]: 35 – 57 years). The median follow-up duration was 173.5 (IQR: 129.0 – 193.3) days. There were no significant differences between cases and controls with respect to age, sex, cardiovascular risk factors, and comorbidities. The levels of N-terminal pro-B natriuretic peptide and troponin I at follow-up did not differ significantly between the two groups. However, the root mean square of successive differences (RMSSD) of R-R intervals was significantly lower in some cases. Neither of the groups had significant arrhythmias. There were no significant differences between the two groups in both awake and asleep blood pressure levels as well as in dipping blood pressure status. In conclusion, COVID-19 infection was associated with reduced heart rate variability (HRV) as manifested by low RMSSD. Given the established link between reduced HRV and increased risks of mortality and sudden cardiac death, these findings warrant further investigation into the long-term cardiovascular impact of COVID-19.