Elsevier

Progress in Cardiovascular Diseases

Available online 19 May 2023
Progress in Cardiovascular Diseases

Cardiopulmonary testing in long COVID-19 versus non–COVID-19 patients with undifferentiated Dyspnea on exertion

https://doi.org/10.1016/j.pcad.2023.05.005Get rights and content

Abstract

Background

Dyspnea and fatigue are characteristics of long SARS-CoV-2 (COVID)-19. Cardiopulmonary exercise testing (CPET) can be used to better evaluate such patients.

Research question

How significantly and by what mechanisms is exercise capacity impaired in patients with long COVID who are coming to a specialized clinic for evaluation?

Study design and methods

We performed a cohort study using the Mayo Clinic exercise testing database. Subjects included consecutive long COVID patients without prior history of heart or lung disease sent from the Post-COVID Care Clinic for CPET. They were compared to a historical group of non–COVID patients with undifferentiated dyspnea also without known cardiac or pulmonary disease. Statistical comparisons were performed by t-test or Pearson's chi2 test controlling for age, sex, and beta blocker use where appropriate.

Results

We found 77 patients with long COVID and 766 control patients. Long COVID patients were younger (47 ± 15 vs 50 ± 10 years, P < .01) and more likely female (70% vs 58%, P < .01). The most prominent difference on CPETs was lower percent predicted peak V̇O2 (73 ± 18 vs 85 ± 23%, p < .0001). Autonomic abnormalities (resting tachycardia, CNS changes, low systolic blood pressure) were seen during CPET more commonly in long COVID patients (34 vs 23%, P < .04), while mild pulmonary abnormalities (mild desaturation, limited breathing reserve, elevated V̇E/V̇CO2) during CPET were similar (19% in both groups) with only 1 long COVID patient showing severe impairment.

Interpretation

We identified severe exercise limitation among long COVID patients. Young women may be at higher risk for these complications. Though mild pulmonary and autonomic impairment were common in long COVID patients, marked limitations were uncommon. We hope our observations help to untangle the physiologic abnormalities responsible for the symptomatology of long COVID.

Keywords

Long COVID-19
Cardiopulmonary exercise testing
fatigue
dyspnea
autonomic abnormalities

Abbreviations

ANA
antinuclear antibodies
BMI
body mass index
BR
breathing reserve
CCP
citrullinated peptide
CK
creatinine kinease
CNS
central nervous system
COVID-19
coronavirus disease 2019
CPET
cardiopulmonary exercise testing
CRP
C - reactive protein
CVD
cardiovascular disease
ECG
electrocardiogram
EMR
electronic medical record
ESR
erythrocyte sedimentation rate
FAC
functional aerobic capacity
Hb
hemoglobin
HR
heart rate
IRB
institutional review board
LVEF
left ventricualr ejection fraction
PCR
polymerase chain reaction
PFT
pulmonary function test
PVC
premature ventricular contraction
RER
respiratory exchange ratio
RF
rheumatoid factor
SARS-CoV-2
severe acute respiratory syndrome coronavirus 2
SBP
systolic blood pressure
TSH
thyroid-stimulating hormone
VE
expired ventilation
E/V̇CO2
minute ventilation/carbon dioxide production
V̇O2
oxygen uptake per minute
VT
ventricular tachycardia

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