Longitudinal Tracking of Autonomic and Cardiovascular Function in Individuals Previously Diagnosed with COVID‐19

Stute, Nina; Province, Valesha; Augenreich, Marc; Stickford, Jonathon; Ratchford, Stephen; Stickford, Abigail

BACKGROUND: Individuals infected with the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) exhibit a wide variety of symptoms, indicating potential systemic effects of the virus. Anecdotally, many patients ‐ even those who experience only mild cases initially ‐ continue to suffer from symptoms months after diagnosis, including indicators of potential autonomic dysfunction like tachycardia upon standing. However, the long‐term impact of and recovery from COVID‐19 on autonomic and cardiovascular function in otherwise healthy individuals remains largely unclear. METHODS: Otherwise healthy young adults (n=11, 6F) who had tested positive for SARS‐CoV‐2 came to the laboratory two times: Visit 1 (V1) was 3‐4 weeks post‐diagnosis, and Visit 2 (V2) was one month later. Muscle sympathetic nerve activity (MSNA; n=2) via microneurography, beat by beat systolic (SBP) and diastolic (DBP) arterial blood pressure via finger photoplethysmography, and heart rate (HR) were continuously measured in subjects at rest, during a 2‐min cold pressor test (CPT), and during 5 min each at 30° and 60° head up tilt (HUT; no MSNA). Paired sample t‐tests and two‐way ANOVA were used to determine differences in the cardiovascular outcome measures between visits. RESULTS: Resting SBP (123 ± 18 vs. 119 ± 17 mmHg), DBP (73 ± 16 vs. 69 ± 7 mmHg), and HR (63 ± 10 vs. 62 ± 9 bpm) did not change from V1 to V2. Preliminary data (n=2) indicates MSNA may decrease from V1 to V2 (14.5 ± 4 vs. 9 ± 3 bursts·min‐1), but the study is currently not powered to examine statistical significance. During the 2‐minute CPT protocol, SBP (150 ± 10 vs. 145 ± 13 mmHg, p=0.08), DBP (94 ± 12 vs. 88 ± 12 mmHg, p=0.10), and HR (77 ± 19 vs. 71 ± 11 bpm, p=0.11) tended to be the same or lower from V1 to V2. Likewise, individual data from two subjects suggests MSNA reactivity during a painful stimulus (CPT) may decrease from V1 to V2 (16 ± 4 vs 10 ± 3 bursts·min‐1). These two subjects also exhibited reduced MSNA during the three‐minute CPT recovery period from V1 to V2 (14 ± 2 vs. 7 ± 1 bursts·min‐1). During both 30° and 60° HUT, SBP, DBP, and HR responses were similar between V1 and V2. CONCLUSION: Young, otherwise healthy individuals infected with SARS‐CoV‐2 may have exaggerated sympathetic neural and cardiovascular responses to physiological stress 3‐4 weeks post‐positive test date. However, preliminary data indicates that sympathetic and cardiovascular reactivity to painful stimuli is reduced from one‐ to two‐months post‐diagnosis. Continued monitoring of autonomic and cardiovascular function is warranted to determine the long‐term consequences of contracting SARS‐CoV‐2.