Cardiopulmonary Exercise Testing (CPX) is essential for the assessment of exercise capacity for patients with Chronic Heart Failure (CHF). Respiratory gas and hemodynamic parameters such as Ventilatory Efficiency (VE/VCO₂ slope), peak oxygen uptake (peak VO₂), and heart rate recovery are established diagnostic and prognostic markers for clinical populations. Previous studies have suggested the clinical value of metrics related to respiratory gas collected during recovery from peak exercise, particularly recovery time to 50% (T1/2) of peak VO₂. The current study explores these metrics in detail during recovery from peak exercise in CHF. Patients with CHF who were referred for CPX and healthy individuals without formal diagnoses were assessed for inclusion. All subjects performed CPX on cycle ergometers to volitional exhaustion and were monitored for at least five minutes of recovery. CPX data were analyzed for overshoot of respiratory exchange ratio (RER=VCO₂/VO₂), ventilatory equivalent for oxygen (VE/VO₂), end-tidal partial pressure of oxygen (PETO₂), and T1/2 of peak VO₂ and VCO₂. Thirty-two patients with CHF and 30 controls were included. Peak VO₂ differed significantly between patients and controls (13.5 ± 3.8 vs. 32.5 ± 9.8 mL/Kg*min^-1, p < 0.001). Mean Left Ventricular Ejection Fraction (LVEF) was 35.9 ± 9.8% for patients with CHF compared to 61.1 ± 8.2% in the control group. The T1/2 of VO₂, VCO₂ and VE was significantly higher in patients (111.3 ± 51.0, 132.0 ± 38.8 and 155.6 ± 45.5s) than in controls (58.08 ± 13.2, 74.3 ± 21.1, 96.7 ± 36.8s; p < 0.001) while the overshoot of PETO₂, VE/VO₂ and RER was significantly lower in patients (7.2 ± 3.3, 41.9 ± 29.1 and 25.0 ± 13.6%) than in controls (10.1 ± 4.6, 62.1 ± 17.7 and 38.7 ± 15.1%; all p < 0.01). Most of the recovery metrics were significantly correlated with peak VO₂ in CHF patients, but not with LVEF. Patients with CHF have a significantly blunted recovery from peak exercise. This is reflected in delays of VO₂, VCO₂, VE, PETO₂, RER and VE/VO₂, reflecting a greater energy required to return to baseline. Abnormal respiratory gas kinetics in CHF was negatively correlated with peak VO₂ but not baseline LVEF.

For the acutely dyspneic patient, discerning bedside between acute decompensated heart failure (ADHF) and COVID-19 is crucial. A lung ultrasound (LUS) is sensitive for detecting these conditions, but not in distinguishing between them; both have bilateral B-lines. The Blue protocol uses pleural sliding to differentiate decreased pneumonia; however, this is not the case in ADHF. Nonetheless, this pleural sliding has never been quantified. Speckled tracking is a technology utilized in the echocardiography field that quantifies the motion of tissues by examining the movement of ultrasound speckles. We conducted a retrospective study of LUS performed in emergency room patients during the COVID-19 pandemic. Speckled tracking of the pleura by applying software to the B-mode of pleura was compared between COVID-19 patients, ADHF patients, and patients with no respiratory complaints. A significant difference was found between the patient groups on speckled tracking both in respect of displacement and velocity. ADHF had the highest displacement, followed by COVID-19, and then non-respiratory patients: 1.63 ± 1.89, 0.59 ± 0.71, and 0.24 ± 0.45, respectively (p < 0.01). A similar trend was seen in velocity with ADHF having the highest velocity 0.34 ± 0.37, followed by COVID-19 0.14 ± 0.71, and non-respiratory patients 0.02 ± 0.09 (p <0.01). Speckled tracking of the pleura is a potential tool for discerning between different causes of dyspnea.

We compared 23 unvaccinated to 15 vaccinated patients previously infected with SARS-CoV-2 in terms of their aerobic capacity measured by a cardio pulmonary exercise test (CPET). Compared with unvaccinated individuals, those vaccinated had a higher heart rate, higher VO2. Our results suggest objective limitations to exercise capacity in the months following acute COVID19 illness, mitigated by vaccination

Patients previously infected with acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may experience post-acute adverse health outcomes, known as long COVID. The most reported symptoms are fatigue, headache and attention/concentration issues, dyspnea and myalgia. In addition, reduced aerobic capacity has been demonstrated in both mild and moderate COVID-19 patients. It is unknown whether COVID-19 vaccination mitigates against reduced aerobic capacity. Our aim was to compare the aerobic capacity of vaccinated and unvaccinated individuals previously infected with SARS-CoV-2. Methods: Individuals aged 18 to 65 years with laboratory-confirmed mild to moderate COVID-19 disease were invited to Ziv Medical Centre, Israel, three months after SARS-CoV-2 infection. We compared individuals unvaccinated at the time of infection to those vaccinated in terms of aerobic capacity, measured using symptom-limited cardiopulmonary exercise test (CPET). Results: We recruited 28 unvaccinated and 22 vaccinated patients. There were no differences in baseline demographic and pulmonary function testing (PFT) parameters. Compared with unvaccinated individuals, those vaccinated had higher V’O₂/kg at peak exercise and at the anaerobic threshold. The V’O₂/kg peak in the unvaccinated group was 83% of predicted vs. 100% in the vaccinated (p < 0.002). At the anaerobic threshold (AT), vaccinated individuals had a higher V’O₂/kg than those unvaccinated. Conclusions: Vaccinated individuals had significantly better exercise performance. Compared with vaccinated individuals, a higher proportion of those unvaccinated performed substantially worse than expected on CPET. These results suggest that vaccination at the time of infection is associated with better aerobic capacity following SARS-CoV-2 infection.