Dysautonomia following COVID-19 is not associated with subjective limitations or symptoms, but is associated with objective functional limitations

Abstract

Background

Individuals who contract coronavirus disease 2019 (COVID-19) can suffer with persistent and debilitating symptoms long after the initial acute illness. Heart rate (HR) profiles determined during cardiopulmonary exercise testing (CPET) and delivered as part of a post-COVID recovery service may provide an insight into presence and impact of dysautonomia on functional ability.

Objective

Using an active, working age, post-COVID-19 population, the aim was to: 1) understand and characterise any association between subjective symptoms and dysautonomia, and 2) identify objective exercise capacity differences between patients classified ‘with’ and ‘without’ dysautonomia.

Methods

Patients referred to a post-COVID-19 service underwent comprehensive clinical assessment, including self-reported symptoms, CPET and secondary care investigations when indicated. Resting HR >75 beats per minute (bpm), HR increase with exercise <89bpm, and HR recovery <25bpm one minute after exercise were used to define dysautonomia. Anonymised data were analysed and associations with symptoms and CPET outcomes determined.

Results

Fifty-one (25%) of the 205 patients reviewed as part of this service evaluation had dysautonomia. There were no associations between symptoms or perceived functional limitation and dysautonomia (p>0.05). Patients with dysautonomia demonstrated objective functional limitations with significantly reduced work rate (219±37 W vs. 253±52 W, p<0.001), peak oxygen consumption (V̇O ₂: 30.6±5.5 ml/kg/min vs. 35.8±7.6 ml/kg/min, p<0.001) and a steeper (less efficient) V̇E/V̇CO ₂ slope (29.9±4.9 vs. 27.7±4.7, p=0.005).

Conclusion

Dysautonomia is associated with objective functional limitations but is not associated with subjective symptoms or limitation.