Longitudinal strain and myocardial work in symptomatic patients having recovered from COVID-19 and possible associations with the severity of the disease.

COVID-19 may have residual consequences in multiple organs, including the cardiovascular system. The purpose of the present investigation is to quantify myocardial function in symptomatic individuals with long COVID and investigate the association between illness severity and myocardial function. A retrospective cross-sectional study was conducted in which symptomatic individuals with previous COVID-19 underwent echocardiographic analysis of left ventricle global longitudinal strain (LVGLS) and myocardial work (MW). Individuals also performed cardiopulmonary testing (CPX) to assess peak oxygen uptake (VO2peak). Differences between illness severity subgroups were analyzed by the Mann-Whitney test. Correlations were calculated using the Spearman correlation test. Multilinear regressions were performed to evaluate the influences of COVID-19 severity, body mass index, age, and sex on MW. Fifty-six individuals were included (critical subgroup: 17; moderate/severe subgroup: 39), 59% females; median age: 56 years (IQR: 43-63). CPX revealed a substantial reduction in VO2peak (median of 53% of predicted values). LVGLS were not statistically different between subgroups. Global wasted work (GWW) was higher in the critical subgroup [146 (104-212) versus 121 (74-163) mmHg%, p = 0.01], and global work efficiency (GWE) was lower in this subgroup [93 (91-95) versus 94 (93-96), p = 0.03]. Illness severity was the only independent predictor of GWW and GWE (GWW: r2 = 0.167; p = 0.009; GWE: r2 = 0.172; p = 0.005) in multilinear regressions. In our study with long COVID-19 individuals, despite having a similar LVGLS, patients had subclinical LV dysfunction, demonstrated only by an increase in GWW and a decrease in GWE.

Dynamic Hyperinflation Impairs Cardiac Performance During Exercise in COPD.

PURPOSE: To investigate the correlation between a plateau in minute ventilation (Equation is included in full-text article.)E during cardiopulmonary exercise tests (CPETs) and its impact on cardiac performance. METHODS: This retrospective study analyzed 2575 CPETs of patients with chronic obstructive pulmonary disease. The study randomly selected 10 patients with a plateau in the (Equation is included in full-text article.)E curve, suggesting dynamic hyperinflation, 10 patients with normal pattern for the (Equation is included in full-text article.)E curve, and 10 healthy persons. Classic CPET variables, the new ventilation hyperinflation index, and the dynamic cardiac constraint index were analyzed. RESULTS: The patients with dynamic hyperinflation presented with lower ventilation at 100% work rate (P < .0001), without significant differences in (Equation is included in full-text article.)E at 50% and 100% work rate. Patients with dynamic hyperinflation also presented with a lower oxygen pulse (O2 pulse) at 100% (P < .0001), without significant difference in O2 pulse at 50% and 100% work rate. The subjects with dynamic hyperinflation had a higher ventilation hyperinflation index (P < .0001) and dynamic cardiac constraints index (P < .0001). The ventilation hyperinflation index correlated with the dynamic cardiac constraints index (r = 0.81, P < .0001); oxygen pulse variation (r =-0.63, P < .001); (Equation is included in full-text article.)E/(Equation is included in full-text article.)CO2 slope (r =-0.57, P < .01); work rate (r =-0.86, P < .0001); (Equation is included in full-text article.)O2 (r =-0.80, P < .0001), and (Equation is included in full-text article.)E (r =-0.83, P < .0001). CONCLUSION: There is a correlation between a plateau in the (Equation is included in full-text article.)E during CPET, suggesting hyperinflation, and it has an impact on cardiac performance.

Current evidence demonstrates similar effects of kilohertz-frequency and low-frequency current on quadriceps evoked torque and discomfort in healthy individuals: a systematic review with meta-analysis.

BACKGROUND: Neuromuscular electrical stimulation (NMES) is widely utilized to enhance muscle performance. However, the optimal NMES waveform with respect to treatment effect has not been established. OBJECTIVE: To investigate the effects of kilohertz-frequency alternating current (KFAC) and low-frequency pulsed current (PC) on quadriceps evoked torque and self-reported discomfort. DATA SOURCES: PubMed, The Cochrane Library, EMBASE, MEDLINE, Physiotherapy Evidence Database (PEDro), SinoMed, ISI Web of Knowledge, and CINAHL were searched for randomized controlled trials (RCTs) and quasi-randomized controlled trials (QRCTs). STUDY SELECTION: Two reviewers independently selected potential studies according to the inclusion criteria, extracted data, and assessed methodological quality. DATA EXTRACTION AND SYNTHESIS: Studies were eligible if they compared KFAC versus PC interventions. Studies that included outcome measures for percentage of maximal isometric voluntary contraction (%MIVC) torque and self-reported discomfort level were eligible for evaluation. Seven studies involving 127 individuals were included. The methodological quality of eligible trials was moderate, with a mean of 5 on the 10-point PEDro scale. Overall, PC was no better than KFAC in terms of evoked torque and there was no difference in self-reported discomfort level. CONCLUSION: KFAC and PC have similar effects on quadriceps evoked torque and self-reported discomfort level in healthy individuals. The small number and overall methodological quality of currently available studies included in this meta-analysis indicate that new RCTs are needed to better determine optimal NMES treatment parameters.

Elastic resistance training to increase muscle strength in elderly: a systematic review with meta-analysis.

Analyze the efficiency of training programs with progressive elastic resistance on muscle strength in elderly 'healthy' and 'not healthy'. It was performed a systematic review in relevant databases to identify controlled clinical trials with outcomes from parameters of muscle strength. Two independent reviewers decided about the inclusion criteria, data extraction and evaluation of methodological quality of the articles. Standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated for relevant outcomes and pooled using a random effects model. Among the 11 studies whose effect sizes were used in the meta-analysis, there were 834 individuals between the ages of 60 and 79. The resistance training with elastic bands showed strong effects on muscle strength in healthy elderly (SMD=1.30; 95% CI: 0.90, 1.71) and with some functional incapacity (SMD=1.01; 95% CI: 0.82, 1.19), and a moderate effect on muscle strength in elderly patients with pathology (SMD=0.54; 95% CI: 0.12, 0.96). There was little information available about the training intensity. The training with elastic resistance proved to be effective for improving muscle strength in 'healthy' and 'not healthy' elderly. Our results suggest that training with elastic resistance is most effective in 'healthy' subjects and with functional limitations, and less effective in subjects with some kind of disorders. To establish dose-response relations from different intensities of training on muscle strength in the elderly, new studies are needed to identify reliable and objective methods of evaluation of muscle strength using elastic materials directly.

Bone mineral density and respiratory muscle strength in male individuals with mental retardation (with and without Down Syndrome).

The purpose of this study was to assess the respiratory muscle strength (RMS) in individuals with mental retardation (MR), with or without Down Syndrome (DS), and its association with bone mineral density (BMD). Forty-five male individuals (15 with DS, 15 with mental retardation (MR) and 15 apparently healthy controls), aged 20-35, participated in this study. Subject assessment included pulmonary function tests, RMS (maximal inspiratory pressure, MIP, and maximal expiratory pressure, MEP) and BMD of the second and fourth lumbar vertebrae. ANOVA was used to test differences amongst groups. Tukey post hoc test was utilized when significant differences were detected with ANOVA. Bivariate correlation for BMD and respiratory muscle strength was calculated with Pearson's coefficient of correlation. Individuals with MR, both with and without DS, have lower FEV1, FVC, MIP and MEP (p<0.001) compared to controls. Individuals with DS also had lower BMD, which was associated with lower MIP and MEP. Hypotonia, sedentary lifestyle and obesity are factors that may explain lower MIP and MEP in DS. Strategies to increase RMS could decrease the risk of osteoporosis in the DS population.