Impact of COVID-19 on cardiac autonomic function in healthy young adults: potential role of symptomatology and time since diagnosis.

Emerging evidence suggests that COVID-19 may affect cardiac autonomic function; however, the limited findings in young adults with COVID-19 have been equivocal. Notably, symptomology and time since diagnosis appear to influence vascular health following COVID-19, but this has not been explored in the context of cardiac autonomic regulation. Therefore, we hypothesized that young adults who had persistent symptoms following COVID-19 would have lower heart rate variability (HRV) and cardiac baroreflex sensitivity (BRS) compared with those who had COVID-19 but were asymptomatic at testing and controls who never had COVID-19. Furthermore, we hypothesized that there would be relationships between cardiac autonomic function measures and time since diagnosis. We studied 27 adults who had COVID-19 and were either asymptomatic (ASYM; n = 15, 6 females); 21 ± 4 yr; 8.4 ± 4.0 wk from diagnosis) or symptomatic (SYM; n = 12, 9 females); 24 ± 3 yr; 12.3 ± 6.2 wk from diagnosis) at testing, and 20 adults who reported never having COVID-19 (24 ± 4 yr, 11 females). Heart rate and beat-to-beat blood pressure were continuously recorded during 5 min of rest to assess HRV and cardiac BRS. HRV [root mean square of successive differences between normal heartbeats (RMSSD); control, 73 ± 50 ms; ASYM, 71 ± 47 ms; and SYM, 84 ± 45 ms; P = 0.774] and cardiac BRS (overall gain; control, 22.3 ± 10.1 ms/mmHg; ASYM, 22.7 ± 12.2 ms/mmHg; and SYM, 24.3 ± 10.8 ms/mmHg; P = 0.871) were not different between groups. However, we found correlations with time since diagnosis for HRV (e.g., RMSSD, r = 0.460, P = 0.016) and cardiac BRS (overall gain, r = 0.470, P = 0.014). These data suggest a transient impact of COVID-19 on cardiac autonomic function that appears mild and unrelated to persistent symptoms in young adults.NEW & NOTEWORTHY The potential role of persistent COVID-19 symptoms on cardiac autonomic function in young adults was investigated. We observed no differences in heart rate variability or cardiac baroreflex sensitivity between controls who never had COVID-19 and those who had COVID-19, regardless of symptomology. However, there were significant relationships between measures of cardiac autonomic function and time since diagnosis, suggesting that COVID-19-related changes in cardiac autonomic function are transient in young, otherwise healthy adults.

Longitudinal observations of sympathetic neural activity and hemodynamics during 6 months recovery from SARS-CoV-2 infection.

Cross-sectional data indicate that acute SARS-CoV-2 infection increases resting muscle sympathetic nerve activity (MSNA) and alters hemodynamic responses to orthostasis in young adults. However, the longitudinal impact of contracting SARS-CoV-2 on autonomic function remains unclear. The aim of this study was to longitudinally track MSNA, sympathetic transduction to blood pressure (BP), and hemodynamics over 6 months following SARS-CoV-2 infection. Young adults positive with SARS-CoV-2 reported to the laboratory three times over 6 months (V1:41 ± 17, V2:108 ± 21, V3:173 ± 16 days post-infection). MSNA, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) were measured at rest, during a cold pressor test (CPT), and at 30° head-up tilt (HUT). Basal SBP (p = 0.019) and DBP (p < 0.001) decreased throughout the 6 months, whereas basal MSNA and HR were not different. Basal sympathetic transduction to BP and estimates of baroreflex sensitivity did not change over time. SBP and DBP were lower during CPT (SBP: p = 0.016, DBP: p = 0.007) and HUT at V3 compared with V1 (SBP: p = 0.041, DBP: p = 0.017), with largely no changes in MSNA. There was a trend toward a visit-by-time interaction for burst incidence (p = 0.055) during HUT, wherein at baseline immediately prior to tilting, burst incidence was lower at V3 compared with V1 (p = 0.014), but there were no differences between visits in the 30 HUT position. These results support impairments to cardiovascular health, and potentially autonomic function, which may improve over time. However, the improvements in BP over 6 months recovery from mild SARS-CoV-2 infection are likely not a direct result of changes in sympathetic activity.