Abstract:
Objectives: The authors used cardiopulmonary exercise testing (CPET) to define unexplained dyspnea in patients with post-acute sequelae of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection (PASC). We assessed participants for criteria to diagnose myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).
Background: Approximately 20% of patients who recover from coronavirus disease (COVID) remain symptomatic. This syndrome is named PASC. Its etiology is unclear. Dyspnea is a frequent symptom.
Methods: The authors performed CPET and symptom assessment for ME/CFS in 41 patients with PASC 8.9 ± 3.3 months after COVID. All patients had normal pulmonary function tests, chest X-ray, and chest computed tomography scans. Peak oxygen consumption (peak VO2), slope of minute ventilation to CO2 production (VE/VCO2 slope), and end tidal pressure of CO2 (PetCO2) were measured. Ventilatory patterns were reviewed with dysfunctional breathing defined as rapid erratic breathing.
Results: Eighteen men and 23 women (average age: 45 ± 13 years) were studied. Left ventricular ejection fraction was 59% ± 9%. Peak VO2 averaged 20.3 ± 7 mL/kg/min (77% ± 21% predicted VO2). VE/VCO2 slope was 30 ± 7. PetCO2 at rest was 33.5 ± 4.5 mm Hg. Twenty-four patients (58.5%) had a peak VO2 <80% predicted. All patients with peak VO2 <80% had a circulatory limitation to exercise. Fifteen of 17 patients with normal peak VO2 had ventilatory abnormalities including peak respiratory rate >55 (n = 3) or dysfunctional breathing (n = 12). For the whole cohort, 88% of patients (n = 36) had ventilatory abnormalities with dysfunctional breathing (n = 26), increased VE/VCO2 (n = 17), and/or hypocapnia PetCO2 <35 (n = 25). Nineteen patients (46%) met criteria for ME/CFS.
Conclusions: Circulatory impairment, abnormal ventilatory pattern, and ME/CFS are common in patients with PASC. The dysfunctional breathing, resting hypocapnia, and ME/CFS may contribute to symptoms. CPET is a valuable tool to assess these patients.
Source: Mancini DM, Brunjes DL, Lala A, Trivieri MG, Contreras JP, Natelson BH. Use of Cardiopulmonary Stress Testing for Patients With Unexplained Dyspnea Post-Coronavirus Disease. JACC Heart Fail. 2021 Dec;9(12):927-937. doi: 10.1016/j.jchf.2021.10.002. PMID: 34857177; PMCID: PMC8629098. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8629098/ (Full text)