Evaluation of myocardial work in patients recovered from the severe form of COVID-19

Background/Introduction

The impact of COVID-19 goes beyond its acute form, and can lead to the persistence of symptoms and the emergence of systemic disorders, defined as Post-Covid or Long-Covid.

Purpose

Assess the late impact on the cardiorespiratory system of patients recovered from severe Covid.

Methods

We performed cross-sectional study that included patients over 18 years of age who recovered from the severe form of COVID-19 after at least 60 days of their discharge. Patients and healthy controls were enrolled to perform transthoracic echocardiography (TTE) and cardiopulmonary exercise testing (CPET).

Results

A total of 52 patients and 24 controls were enrolled. The standard TTE parameters (end diastolic diameters, left ventricular ejection fraction, diastolic function and right ventricular systolic function) showed no difference when compared to the control group. When analyzing the myocardial work, there was a higher Wasted MW (GWW): 135 mmHg% vs 84.5 mmHg% (p=0.002), with lower MW Efficiency (GWE): 94 vs. 96 (p=0.003); as well as lower values of global strain: cases = 18.6% vs. 20.1% (p=0.009). No differences were found in the Constructive MW (GWC) and MW Global Index (GWI). In the CPET data we found lower peak values for the VO2: 24 ml/kg/min vs. 32.75 ml/kg/min (p<0.001); for the Heart Rate: 162 bpm vs. 175 bpm (p<0.001); for the Ventilation: 79.3 L/min vs. 109.85 L/min (p<0.001) and Respiratory Exchange Ratio: 1.12 vs. 1.19 (p=0.004). There was no difference in the maximum load reached, neither in the oxygen pulse values and in the Ve/CO2 slope. In relation to the oxygen kinetics, there was a significant reduction in OUES%: 85% vs. 98% (p=0.03); as well as an extended T½: 112 s vs. 88.5 s (p<0.001); and a slowing of the fall in heart rate in recovery time, as measured by the Heart Rate decay: −17.32 bpm vs. −22.08 bpm (p=0.005).

Conclusion

Patients recovered from the severe form of COVID-19 had higher GWW with lower efficiency (GWE). Such findings, added to changes in oxygen kinetics during exercise, may point to a possible cardiocirculatory mechanism associated with decreased aerobic capacity.

Funding Acknowledgement

Type of funding sources: None.

Paradoxical movement of the lower ribcage at rest and during exercise in COPD patients

Paradoxical inward displacement of the costal margin during inspiration is observed in many chronic obstructive pulmonary disease patients at rest but its importance is unclear. The current authors studied 20 patients (forced expiratory volume in one second 32.6+/-11.7, functional residual capacity 186+/-32% predicted) and 10 healthy controls at rest and during symptom-limited incremental exercise. With optoelectronic plethysmography, the phase shift between pulmonary and abdominal ribcage volumes and the percentage of inspiratory time the ribcage compartments moved in opposite directions were quantified, using control data to define the normal range of movement. Eight patients showed lower ribcage inspiratory paradox at rest (P+), while 12 patients did not (P-). This was unrelated to resting lung function or exercise tolerance. Total end-expiratory chest wall volume (EEV(cw)) increased immediately when exercise began in P+ patients, but later in exercise in P- patients. This difference in EEV(cw) was mainly due to a greater increase of end-expiratory pulmonary ribcage volume in P+ patients. During exercise, dyspnoea increased similarly in the two groups, while leg effort increased more markedly in the patients without paradox. In conclusion, lower ribcage paradox at rest is reproducible and associated with early-onset hyperinflation of the chest wall and predominant dyspnoea at end-exercise. When paradox is absent, the sense of leg effort becomes a more important symptom limiting exercise.

Inspiratory fraction and exercise impairment in COPD patients GOLD stages II-III

The inspiratory-to-total lung capacity ratio or "inspiratory fraction" (inspiratory capacity(IC)/total lung capacity (TLC)) may be functionally more representative than traditional indices of resting airflow limitation and lung hyperinflation in patients with chronic obstructive pulmonary disease (COPD). In the present retrospective study, a comparison was made of the individual performance of post-bronchodilator IC, IC/TLC and forced expiratory volume in one second (FEV(1)) in predicting a severely reduced peak oxygen uptake (V'(O(2)); <60% predicted) in 44 COPD patients Global Initiative for Chronic Obstructive Lung Disease stages II-III (post-bronchodilator FEV(1) ranging from 31-79% pred). Patients with lower IC/TLC values (<or=0.28) showed increased lung volumes and reduced exercise capacity as compared with other subjects. Following a multiple linear regression analysis, only IC/TLC and FEV(1) remained as independent predictors of V'(O(2)) (r(2) = 0.33). A receiver operating characteristic (ROC) curve analysis revealed that an IC/TLC <or=0.28 had the highest specificity (89.6%), positive predictive value (80%) and overall accuracy (86.3%) in identifying patients with V'(O(2)) <60% pred. In addition, the area under the ROC curve tended to be higher for IC/TLC than IC. In conclusion, post-bronchodilator total lung capacity-corrected inspiratory fraction provides useful information in addition to forced expiratory volume in one second and inspiratory capacity, to estimate the likelihood of chronic obstructive pulmonary disease patients to present with severely reduced maximal exercise capacity.