Diagnostic Usefulness of Spiroergometry and Risk Factors of Long COVID in Patients with Normal Left Ventricular Ejection Fraction

Predictors of Long-COVID and Chronic Impairment of Exercise Tolerance in Spiroergometry in Patients after 15 Months of COVID-19 Recovery

BACKGROUND

The aim of the study was to identify factors that may cause the presence of long COVID and to assess factors that affect chronic limited exercise tolerance in spiroergometry after one-year follow-up in patients who had recovered from COVID-19.

METHODS

Of 146 patients hospitalised in the Cardiology Department, 82 completed a one-year follow-up (at least 15 months post-COVID-19 recovery). We compared their conditions at initial screening and follow-up to analyse the course of long COVID and exercise intolerance mechanisms. Clinical examinations, laboratory tests, echocardiography, cardiopulmonary exercise testing, and body composition analysis were performed.

RESULTS

The patients, after one-year follow-up, had significantly higher levels of high-sensitivity cardiac troponin T (hs-cTnT) (p = 0.03), left atrium diameter (LA) (p = 0.03), respiratory exchange ratio (RER) (p = 0.008), and total body water content percentage (TBW%) (p < 0.0001) compared to the 3-month assessment. They also had lower forced vital capacity in litres (FVC) (p = 0.02) and percentage (FVC%) (p = 0.001). The factors independently associated with a decline in maximum oxygen uptake (VO2max) after one-year follow-up included the percentage of fat (OR 2.16, 95% CI: 0.51-0.77; p = 0.03), end-diastolic volume (EDV) (OR 2.38, 95% CI 0.53-0.78; p = 0.02), and end-systolic volume (ESV) (OR 2.3, 95% CI: 0.52-0.78; p = 0.02).

CONCLUSIONS

Higher left ventricular volumes and fat content (%) were associated with a reduced peak VO2max when assessed 15 months after COVID-19 recovery.