Impact of long COVID on the heart rate variability at rest and during deep breathing maneuver

While the majority of individuals with coronavirus disease 2019 (COVID-19) recover completely, a significant percentage experience persistent symptom, which has been characterized as Long COVID and may be associated with cardiac and autonomic dysfunction. We evaluated heart rate variability (HRV) at rest and during deep-breathing (M-RSA) in patients with Long COVID. Case-control design involved 21 patients with Long COVID and 20 controls; the HRV was evaluated (POLAR system) at rest in the supine position and during M-RSA and expressed in time domain and non-linear analysis. In the supine position we found a reduction HRV measures in Long COVID' patients compared to controls for: Mean_iRR (p < 0.001), STD_iRR (p < 0.001); STD_HR (p < 0.001); SD1 (p < 0.001); SD2 (p < 0.001); alpha2 (p < 0.001). In the M-RSA we found reduction Mean_iRR (p < 0.001), STD_iRR (p < 0.001), STD_HR (p < 0.001), rMSSD (p < 0.001), RR_tri-index (p < 0.001) in Long COVID' patients except for highest Mean_HR p < 0.001. In conclusion, Long COVID reduced HRV at rest and during deep breathing. These findings may imply impairment of cardiac autonomic control when symptoms of COVID-19 persist following initial recovery.

Proportional Assist Ventilation Improves Leg Muscle Reoxygenation After Exercise in Heart Failure With Reduced Ejection Fraction

Background

Respiratory muscle unloading through proportional assist ventilation (PAV) may enhance leg oxygen delivery, thereby speeding off-exercise oxygen uptake ( V . ⁢ O 2 ) kinetics in patients with heart failure with reduced left ventricular ejection fraction (HFrEF).

Methods

Ten male patients (HFrEF = 26 ± 9%, age 50 ± 13 years, and body mass index 25 ± 3 kg m²) underwent two constant work rate tests at 80% peak of maximal cardiopulmonary exercise test to tolerance under PAV and sham ventilation. Post-exercise kinetics of V . ⁢ O 2 , vastus lateralis deoxyhemoglobin ([deoxy-Hb + Mb]) by near-infrared spectroscopy, and cardiac output (Q _T ) by impedance cardiography were assessed.

Results

PAV prolonged exercise tolerance compared with sham (587 ± 390 s vs. 444 ± 296 s, respectively; p = 0.01). PAV significantly accelerated V . ⁢ O 2 recovery (τ = 56 ± 22 s vs. 77 ± 42 s; p < 0.05), being associated with a faster decline in Δ[deoxy-Hb + Mb] and Q _T compared with sham (τ = 31 ± 19 s vs. 42 ± 22 s and 39 ± 22 s vs. 78 ± 46 s, p < 0.05). Faster off-exercise decrease in Q _T with PAV was related to longer exercise duration (r = -0.76; p < 0.05).

Conclusion

PAV accelerates the recovery of central hemodynamics and muscle oxygenation in HFrEF. These beneficial effects might prove useful to improve the tolerance to repeated exercise during cardiac rehabilitation.

Association of exercise capacity and endothelial function in patients with severe exacerbations of chronic obstructive pulmonary disease

Severe acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are associated with significant poor outcomes including an increased risk of cardiovascular (CV) events and exercise intolerance. Endothelial dysfunction might contribute to an impaired vascular homeostasis and consequently to CV events and exercise capacity. This study aimed to evaluate the association between exercise capacity and endothelial function in patients with severe AECOPD. Forty-five COPD patients diagnosed with severe AECOPD and admitted to the University Hospital of São Carlos from 2017 to 2019 were enrolled in this observational clinical study. Endothelial Function was assessed by brachial artery ultrasonography (M-Turbo, Sonosite, Bottle, WA, USA) and Flow Mediated Dilatation (FMD) technique in absolute (mm) and percentage values (%). Walking distance (6MWD) obtained by six-minute walk test was considered to characterize the exercise capacity. Pearson's correlation analysis and linear regression model were applied and a significance level of 5%. There was a significant positive correlation between exercise capacity and endothelial function. Pearson correlation coefficient were 0.36 (p = 0.02) and 0.40 (p = 0.01) between 6MWD and FMD in mm and %, respectively. Linear regression model revealed 6MWD (p = 0.007), accounting for 15% of FMD (%) variance (R2 adjusted). FMD (%) = 2.11 + (0.0081*6MWD). Exercise capacity is associated with endothelial function in patients with severe AECOPD. FMD was found to be increasing with increasing walked distance. Further research is needed to provide evidence of effectiveness of rehabilitation on exercise capacity and endothelial function in these patients and its prognostic value.

Validity, intra and inter-reliability of manual evaluation of the respiratory muscle strength in asthmatic patients

OBJECTIVE

This study investigated the concurrent validity, inter and intra-reliability of manual evaluation in Asthma patients.

METHODS

Twenty six asthma patients were assessed. Maximal respiratory muscle strength (Mrms) was tested by inspiratory and expiratory pressure (MIP and MEP, respectively) trough manovacuometer. In addition, Mrms of diaphragm (anterior and posterior), Intercostals (lower and upper portion) and Rectus abdominal were obtained manually, according to Medical Research Council (MRC) scale. Two independents evaluators, previously trained, made both measurements.

RESULTS

Reproducibility of Mrms intra-evaluators: anterior diaphragm (ICCs, 0.79 and 0.67); Posterior portion of the diaphragm (ICCs, 0.43 and 0.51); Upper intercostals (ICCs, 0.47 and 0.40); Lower intercostals (ICCs, 0.81 and 0.51) and rectus abdominal (ICCs, 1.0). Inter-reproducibility of anterior diaphragm was low to moderate, while intercostals (upper and lower portion) was relatively low. However, rectus abdominal presented high reproducibility reflecting in almost perfect agreement. In addition, we found positive correlations between MIP versus Lower Intercostals (r = .60, p = .007) and MEP versus rectus abdominal (r = .41, p = .04).

CONCLUSION

In asthmatic patients, manual evaluation of the respiratory muscles is reliable. In addition, maximal respiratory pressures using manometer assessment were related to manual evaluation, in special to diaphragm and rectus abdominal muscles.

Thoracoabdominal mobility evaluation of asthmatic patients in physiotherapy practice: Intra-rater reliability

BACKGROUND

The evaluation of thoracoabdominal mobility is a tool extensively used in the physiotherapy practice in different populations. Photogrammetry may be a simple tool to analyse thoracoabdominal mobility; however, it is unclear whether this assessment can be a reliable method.

AIM

To test the reliability intra-examinator by photogrammetry in asthmatic patients and in health controls.

METHODS

Twenty-six asthmatic patients (29 ± 9 years) and 14 healthy matched controls (27 ± 8 years) were assessed by thoracoabdominal mobility. Photographs during rest, during inspiration and expiration maximum were used to calculate latero-lateral and antero-posterior diameters of the thorax (at axillary and xiphoid levels) and umbilical by markers positioned in osseous structures. An evaluator obtained the same measurements in an 8-day interval.

RESULTS

We found a moderate reliability for axillary, xiphoid and umbilical mobility (average intraclass correlation coefficient [ICC] respectively [0.68, 0.55 and 0.73]) for asthmatic group. In addition, for control group, we found a moderate reliability for axillary mobility (average ICC respectively [0.68] and a good reliability for xiphoid and umbilical mobility) (average ICC 0.81 and 0.70). Bland-Altman plots showed goods limit of agreement in photos 1 and 2 in both groups.

CONCLUSION

The photogrammetric analysis of thoracoabdominal mobility presented itself as a reliable method and may be used in clinical practice in asthmatic patients and in controls.

DNA damage and repair capacity in lymphocyte of chronic obstructive pulmonary diseases patients during physical exercise with oxygen supplementation

BACKGROUND

We hypothesized that the use of oxygen supplementation during aerobic exercise induces less DNA damage than exercise alone. The aim of this study is to assess the level of DNA damage induced by physical exercise with and without oxygen supplementation in chronic obstructive pulmonary diseases (COPD) patients.

METHODS

Peripheral blood was collected before and after aerobic exercise in two conditions: (I) aerobic exercise without oxygen supplementation (AE group) and (II) with oxygen supplementation (AE-O2 group). Lymphocytes were collected to perform the alkaline version of the Comet Assay. To assess the susceptibility to exogenous DNA damage, the lymphocytes were treated with methyl methanesulphonate (MMS) for 1-h or 3-h. After 3-h treatment, the percentage of residual damage was calculated assuming the value of 1-h MMS treatment as 100%.

RESULTS

AE group showed lower induced damage (1 h of MMS treatment) and consequently less DNA repair compared to AE-O2 group. AE-O2 group showed an increase in the induced DNA damage (1 h of MMS treatment) and an increased DNA repair capacity. Within the AE-O2 group, in the post-exercise situation the induced DNA damage after 1 h of MMS treatment was higher (p = 0.01) than in the pre-exercise.

CONCLUSION

COPD patients who performed physical exercise associated with oxygen supplementation had a better response to DNA damage induced by MMS and a better DNA repair when compared to the condition of physical exercise without oxygen supplementation.

TRIAL REGISTRATION

UNISC N374.298. Registered 04 JUN 2013 (retrospectively registered).

DNA damage and repair capacity in lymphocyte of chronic obstructive pulmonary diseases patients during physical exercise with oxygen supplementation

Background: We hypothesized that the use of oxygen supplementation during aerobic exercise induces less DNA damage than exercise alone. The aim of this study is to assess the level of DNA damage induced by physical exercise with and without oxygen supplementation in chronic obstructive pulmonary diseases (COPD) patients. Methods: Peripheral blood was collected before and after aerobic exercise in two conditions: (I) aerobic exercise without oxygen supplementation (AE group) and (II) with oxygen supplementation (AE-O2 group). Lymphocytes were collected to perform the alkaline version of the Comet Assay. To assess the susceptibility to exogenous DNA damage, the lymphocytes were treated with methyl methanesulphonate (MMS) for 1-h or 3-h. After 3-h treatment, the percentage of residual damage was calculated assuming the value of 1-h MMS treatment as 100%. Results: AE group showed lower induced damage (1 h of MMS treatment) and consequently less DNA repair compared to AE-O2 group. AE-O2 group showed an increase in the induced DNA damage (1 h of MMS treatment) and an increased DNA repair capacity. Within the AE-O2 group, in the post-exercise situation the induced DNA damage after 1 h of MMS treatment was higher (p = 0.01) than in the pre-exercise. Conclusion: COPD patients who performed physical exercise associated with oxygen supplementation had a better response to DNA damage induced by MMS and a better DNA repair when compared to the condition of physical exercise without oxygen supplementation.Trial registration: UNISC N374.298. Registered 04 JUN 2013 (retrospectively registered).