McGuire S; Horton EJ; Renshaw D; Chan K; Krishnan N; McGregor G;

American journal of physiology. Renal physiology [Am J Physiol Renal Physiol] 2020 Aug 03. Date of Electronic Publication: 2020 Aug 03.

Background: Aerobic capacity is impaired in end-stage renal disease (ESRD), reducing quality of life and longevity. Whilst determinants of maximal exercise intolerance are well defined, little is known of limitation during submaximal exercise. By comparing ESRD and healthy controls, the aim of this study was to characterise mechanisms of exercise intolerance in ESRD by assessing cardiopulmonary physiology at rest and during exercise.
Methods: Resting spirometry and echocardiography were performed in 20 ESRD participants and 20 healthy age and gender matched controls. Exercise tolerance was assessed with ventilatory gas exchange and central hemodynamics during a maximal cardiopulmonary exercise test (CPEX) and 30 minutes of submaximal constant load exercise (CLEX).
Results: Left ventricular mass (292 ± 102 vs. 185 ± 83 g; p = 0.01) and filling pressure (E/e’: 6.48 ± 3.57 vs. 12.09 ± 6.50 m/s; p = 0.02) were higher in ESRD; forced vital capacity (3.44 ± 1 vs. 4.29 ± 0.95 L/min; p = 0.03) and peak VO ₂ (13.3 ± 2.7 vs. 24.6 ± 7.3 ml.kg ^-1 .min ^-1 ; p < 0.001) were lower. During CLEX, the relative increase in (a-v) O ₂ difference (13 ± 18 vs. 74 ± 18%) and heart rate (32 ± 18 vs. 75 ± 29%) were less in ESRD despite exercise being performed at a higher percentage of maximum VE (48 ± 3 vs 39 ± 3%) and HR (82 ± 2 vs. 64 ± 2%).
Conclusion: Ventilatory and chronotropic incompetence contribute to exercise intolerance in ESRD. Both are potential targets for medical and lifestyle interventions.

Abdelbasset WK; Osailan A;

Kardiologiia [Kardiologiia] 2020 Jul 07; Vol. 60 (6), pp. 938. Date of Electronic Publication: 2020 Jul 07.

Background Sleep disturbance and ventilator inefficiency are considered two of the most critical complications for general human wellbeing, particularly in elderly heart failure (HF) patients. Studies examining the effect of low-intensity aerobic exercise in the treatment of sleep disturbance and ventilatory inefficiency in this population of patients are limited.Objective The purpose of the current pilot study was to check the effect of low-intensity aerobic exercise on the quality of sleep and ventilatory efficiency in elderly HF patients.Materials and methods Design: pilot study.
Setting: outpatient physical therapy clinic within Cairo University regional hospital.
Participants: eight elderly HF patients (6 men, 2 women) with a mean age of 69.4±4.2 years.
Intervention: participants were recruited for a low-intensity exercise program (40 to 50% of maximum heart rate for 30-40 minutes), five sessions weekly for four weeks. Exercise intensity was monitored during the sessions using heart rate.
Outcome Measure: sleep quality was assessed pre- and post- four weeks of exercise program usingthe Pittsburgh sleep quality index (PSQI) and ventilatory efficiency was assessed using cardiopulmonary exercise test.Results HF patients (II-III NYHA), mean age 69.4±4.2 years, body mass index 23.7±2.7 kg/m2, ejection fraction 32.7±4.5 %, VO2peak 16.27±4.2 ml/kg/min, VE/VCO2 30.81±12.7. The mean of global PSQI score ranged between 8.2 to 11.4 with a mean of 9.7±3.4 which indicates that the participants experienced sleep disturbance. The post-exercise assessment showed that patients have reported a significant improvement of all PSQI domains compared with baseline assessment (p<0.05). VO2peak significantly increased from 16.27±4.2 pre-intervention to 20.03±2.6 ml/kg/min post-intervention (p=0.049) whereas VE/VCO2 slightly decreased with a non-significant difference at the end of the study program (p=0.594) indicating animprovement of ventilator efficiencyand overall cardiorespiratory fitness.Conclusion Short-term application of low-intensity aerobic exercise (4 weeks) may improve the quality of sleep and ventilator efficiency in elderly HF patients. The study findings encourage elderly HF patients with sleep disturbance to adhere to the exercise training program. Also, cardiac rehabilitation programs with low intensity of aerobic exercise should be proposed to these patients by their health care provider.

Nakade T; Adachi H; Murata M; Naito S;

Circulation journal : official journal of the Japanese Circulation Society [Circ J] 2020 Jul 29. Date of Electronic Publication: 2020 Jul 29.

Background: The increase in stroke volume during inotropic stimulation in patients with heart failure with reduced ejection fraction (HFrEF) is called the “pump function reserve.” Few studies have reported on the relationship between pump function reserve and HF prognosis. In HFrEF patients who have pump function reserve, stroke volume increases during exercise. Simply put, the pulse pressure change (∆PP) during cardiopulmonary exercise testing (CPX) is closely related to the prognosis of patients with HFrEF. We hypothesized that ∆PP could predict disease severity and cardiovascular death in patients with HFrEF.Methods and Results:A total of 224 patients with HFrEF who underwent symptom-limited maximal CPX between 2012 and 2016 were enrolled. During a median follow-up of 1.5 years, cardiovascular death occurred in 54 participants (24%). Patients who died demonstrated a lower ∆PP between rest and peak exercise (∆PP [peak-rest]) than those who survived (P<0.001). Cox regression analyses revealed that ∆PP, slope of the relationship between minute ventilation and carbon dioxide production, and B-type natriuretic peptide level were independent predictors of cardiovascular death in patients with HFrEF (P=0.001, 0.021, and <0.001, respectively).
Conclusions: ∆PP (peak-rest) can accurately predict cardiovascular death in patients with HFrEF and may be a useful new prognostic indicator in these patients.

Beltrame T, Gois MO, Hoffmann U, Koschate J, Hughson RL, Frade MCM, Linares SN, Torres RDS, Catai AM

J Appl Physiol (1985). 2020 Jul 30. doi: 10.1152/japplphysiol.00310.2020. Online ahead of print.

Efforts to better understand cardiorespiratory health are relevant for the future development of optimized physical activity programs. We aimed to explore the impact of the signal quality on the expected associations between the ability of the aerobic system in supplying energy as fast as possible during moderate exercise transitions with its maximum capacity to supply energy during maximal exertion. It was hypothesized that a slower aerobic system response during moderate exercise transitions is associated with a lower maximal aerobic power; however, this relationship relies on the quality of the oxygen uptake dataset.
Forty-three apparently healthy participants performed a moderate constant work rate (CWR) followed by a pseudorandom binary sequence (PRBS) exercise protocol on a cycle ergometer. Participants also performed a maximum incremental cardiopulmonary exercise testing (CPET). The maximal aerobic power was evaluated by the peak oxygen uptake during the CPET and the aerobic fitness was estimated from different approaches for oxygen uptake dynamics analysis during the CWR and PRBS protocols at different levels of signal-to-noise ratio. The product moment correlation coefficient was used to evaluate the correlation level between variables. Aerobic fitness was correlated with maximum aerobic power, but this correlation increased as a function of the signal-to-noise ratio.
Aerobic fitness is related to maximal aerobic power; however, this association appeared to be highly dependent on the data quality and analysis for aerobic fitness evaluation. Our results show that simpler moderate exercise protocols might be as good as maximal exertion exercise protocols to obtain indexes related to cardiorespiratory health.

Gulsin GS; Henson J; Brady EM; Sargeant JA; Wilmot EG; Athithan L; Htike ZZ; Marsh AM; Biglands JD; Kellman P; Khunti K; Webb D; Davies MJ; Yates T; McCann GP;

Diabetes care [Diabetes Care] 2020 Jul 17. Date of Electronic Publication: 2020 Jul 17.

Objective: To assess the relationship between subclinical cardiac dysfunction and aerobic exercise capacity (peak VO ₂ ) in adults with type 2 diabetes (T2D), a group at high risk of developing heart failure.
Research Design and Methods: Cross-sectional study. We prospectively enrolled a multiethnic cohort of asymptomatic adults with T2D and no history, signs, or symptoms of cardiovascular disease. Age-, sex-, and ethnicity-matched control subjects were recruited for comparison. Participants underwent bioanthropometric profiling, cardiopulmonary exercise testing, and cardiovascular magnetic resonance with adenosine stress perfusion imaging. Multivariable linear regression analysis was undertaken to identify independent associations between measures of cardiovascular structure and function and peak VO ₂ .
Results: A total of 247 adults with T2D (aged 51.8 ± 11.9 years, 55% males, 37% black or south Asian ethnicity, HbA _1c 7.4 ± 1.1% [57 ± 12 mmol/mol], and duration of diabetes 61 [32-120] months) and 78 control subjects were included. Subjects with T2D had increased concentric left ventricular remodelling, reduced myocardial perfusion reserve (MPR), and markedly lower aerobic exercise capacity (peak VO ₂ 18.0 ± 6.6 vs. 27.8 ± 9.0 mL/kg/min; P < 0.001) compared with control subjects. In a multivariable linear regression model containing age, sex, ethnicity, smoking status, and systolic blood pressure, only MPR (β = 0.822; P = 0.006) and left ventricular diastolic filling pressure (E/e’) (β = -0.388; P = 0.001) were independently associated with peak VO ₂ in subjects with T2D.
Conclusions: In a multiethnic cohort of asymptomatic people with T2D, MPR and diastolic function are key determinants of aerobic exercise capacity, independent of age, sex, ethnicity, smoking status, or blood pressure

Riedel B; Li MH; Lee CHA; Ismail H; Cuthbertson BH; Wijeysundera DN; Ho KM;

British journal of anaesthesia [Br J Anaesth] 2020 Jul 17. Date of Electronic Publication: 2020 Jul 17.

Background: Accurate assessment of functional capacity, a predictor of postoperative morbidity and mortality, is essential to improving surgical planning and outcomes. We assessed if all 12 items of the Duke Activity Status Index (DASI) were equally important in reflecting exercise capacity.
Methods: In this secondary cross-sectional analysis of the international, multicentre Measurement of Exercise Tolerance before Surgery (METS) study, we assessed cardiopulmonary exercise testing and DASI data from 1455 participants. Multivariable regression analyses were used to revise the DASI model in predicting an anaerobic threshold (AT) >11 ml kg ^-1 min ^-1 and peak oxygen consumption (VO ₂ peak) >16 ml kg ^-1 min ^-1 , cut-points that represent a reduced risk of postoperative complications.
Results: Five questions were identified to have dominance in predicting AT>11 ml kg ^-1 min ^-1 and VO ₂ peak>16 ml.kg ^-1 min ^-1 . These items were included in the M-DASI-5Q and retained utility in predicting AT>11 ml.kg ^-1 .min ^-1 (area under the receiver-operating-characteristic [AUROC]-AT: M-DASI-5Q=0.67 vs original 12-question DASI=0.66) and VO ₂ peak (AUROC-VO2 peak: M-DASI-5Q 0.73 vs original 12-question DASI 0.71). Conversely, in a sensitivity analysis we removed one potentially sensitive question related to the ability to have sexual relations, and the ability of the remaining four questions (M-DASI-4Q) to predict an adequate functional threshold remained no worse than the original 12-question DASI model. Adding a dynamic component to the M-DASI-4Q by assessing the chronotropic response to exercise improved its ability to discriminate between those with VO ₂ peak>16 ml.kg ^-1 .min ^-1 and VO ₂ peak<16 ml.kg ^-1 .min ^-1 .
Conclusions: The M-DASI provides a simple screening tool for further preoperative evaluation, including with cardiopulmonary exercise testing, to guide perioperative management.

Schoenfeld J; Schindler Haller B; Holdenrieder S; Nieman DC; Halle M; La Gerche A; Scherr J;

BMJ open sport & exercise medicine [BMJ Open Sport Exerc Med] 2020 Jul 19; Vol. 6 (1), pp. e000786. Date of Electronic Publication: 2020 Jul 19 (Print Publication: 2020).

Introduction: Prolonged strenuous exercise training may result in structural, functional and electrical cardiac remodelling, as well as vascular and myocardial injuries. However, the extent to which high-volume, intense exercise is associated with arrhythmias, myocardial fibrosis, coronary heart disease and pathological alterations of the vasculature remains unknown. In addition, there is no clear consensus on the clinical significance of these exercise-induced changes. Previous studies typically used cross-sectional designs and examined exercise-induced cardiovascular changes in small cohorts of athletes for up to 3-7 days of recovery. Long-term longitudinal studies investigating cardiovascular changes induced by prolonged strenuous exercise in large cohorts of athletes are needed to improve scientific understanding in this area.
Methods and Analysis: In this prospective observational monocenter study, 277 participants of the Beer, Marathon, Genetics, Inflammation and the Cardiovascular System (Be-MaGIC) study (ClinicalTrials.gov: NCT00933218) will be invited to participate in this 10-year follow-up study. A minimum target sample size of 130 participants will be included in the study. Participating athletes will be examined via the following: anthropometry, resting electrocardiography and echocardiography, blood sampling, retinal vessel diameters, carotid sonography and cardiopulmonary exercise testing, including exercise electrocardiography.
Discussion: This longitudinal study will provide comprehensive data on physiological changes in the cardiovascular system and the development of pathologies after a 10-year period of prolonged and strenuous endurance exercise. Since the participants will have engaged in a wide range of training loads and competitive race events, this study will provide useful risk factor determinants and training load cut-off values. The primary endpoint is the association between the exercise-induced increase in cardiac troponin during the Munich marathon 2009 and the decline in right ventricular ejection fraction over the next 10 years.
Trial Registration Number: NCT04166903.

Avesani M;Borrelli N; Krupickova S;Sabatino J; Donne GD; Ibrahim A; Piccinelli E; Josen M; Michielon G; Fraisse A; Iliceto S; Di Salvo G;

International journal of cardiology [Int J Cardiol] 2020 Jul 20. Date of Electronic Publication: 2020 Jul 20.

Background: Pulmonary regurgitation (PR) and right ventricular (RV) dilatation and disfunction are common in patients with repaired Tetralogy of Fallot (r-TOF).
Aims: To compare Echo data with the gold standard CMR in a paediatric population of r-TOF with significant PR, to assess the reliability of standard and advanced echo parameters. In addition, to evaluate their correlation with peak oxygen consumption (VO ₂ ).
Methods and Results: All patients underwent standard echo-Doppler study, speckle tracking analysis, and CMR to assess PR and RV size and function. Thirty-six patients underwent also cardiopulmonary exercise test. Fourty-six patients (aged 13.7 ± 3.0) were included. Echo derived RV areas correlated with CMR RV volumes (p < .0001, r = 0.72). RV end-diastolic area > 21.9 cm ² /m ² had a good sensitivity (83.3%) and specificity (73.5%) to identify a RV end-diastolic volume ≥ 150 ml/m ² . RVEF was preserved in all patients, while TAPSE was reduced in 78.2% and RVGLS in 60.8%. Flow-reversal in pulmonary branches showed a sensitivity of 95.8% and a specificity of 59.1% to identify CMR pulmonary regurgitant fraction (RF) ≥ 35%. None of the CMR parameters correlated with peak VO ₂ . Among the Echo data only right atrial strain (RAS) correlated with peak VO _2.
CONCLUSION: In children, flow-reversal in pulmonary branches identifies hemodynamically significant RF with a good sensitivity but poor specificity. RV area by echocardiogram is a valid first-line parameter to screen RV dilation. RV longitudinal systolic dysfunction coexists with a still preserved EF. RAS correlates strongly with peak VO ₂ and should be added in their follow up.

Burstein DS, Mcbride MG, Rossano JW, O’Connor MJ, Lin KY, Mascio CE(1), White R, Iacobellis K, Rosenthal T(1), Paridon SM.

ASAIO J. 2020 Jul 17. doi: 10.1097/MAT.0000000000001231. Online ahead of print.

Exercise rehabilitation during pediatric ventricular assist device (VAD) support aims to improve musculoskeletal strengthening while awaiting heart transplantation (HT). This study aimed to determine whether increasing VAD pump speed during exercise testing and training improves exercise capacity.
A single-center cohort study was performed comparing changes in exercise capacity on serial cardiopulmonary exercise testing (CPET) after exercise training at a fixed VAD pump speed (historical cohort from 2014 to 2017) compared with a prospective cohort (2017-2019) who underwent increasing pump speed during exercise training. All children were supported with intracorporeal continuous-flow VAD. Four subjects (13 ± 2.8 years) were included in the historical cohort, and 6 subjects (14 ± 1.7 years) were enrolled in the prospective cohort. Ninety percent had dilated cardiomyopathy, and one had single ventricle Fontan physiology. Baseline maximal oxygen consumption (VO2) was 19 ± 6.3 ml/kg/min.
After exercise training with increased pump speed, there was substantial improvement in aerobic capacity (maximal VO2 increased 42% vs. decreased 3%, respectively) and working capacity (maximal work increased 49% vs. 13%, respectively) compared with fixed pump speed. There were no adverse events reported in either the fixed or increased pump speed cohorts. Increasing VAD pump speed during exercise training results in substantial improvement in both physical working and aerobic capacity compared a fixed pump speed in children on VAD support regardless of single or biventricular ventricle physiology. Further study of a larger cohort is needed to validate these findings to improve the approach to pediatric cardiac rehabilitation in this population.

Raghuveer, G. Hartz, J. Lubans, D. R. Takken, T. Wiltz, J. L. Mietus-Snyder, M. Perak, A. M. Baker-Smith, C. Pietris, N. Edwards, N. M.

Circulation. 2020:CIR0000000000000866.

Cardiorespiratory fitness (CRF) refers to the capacity of the circulatory and respiratory systems to supply oxygen to skeletal muscle mitochondria for energy production needed during physical activity. CRF is an important marker of physical and mental health and academic achievement in youth. However, only 40% of US youth are currently believed to have healthy CRF. In this statement, we review the physiological principles that determine CRF, the tools that are available to assess CRF, the modifiable and nonmodifiable factors influencing CRF, the association of CRF with markers of health in otherwise healthy youth, and the temporal trends in CRF both in the United States and internationally. Development of a cost-effective CRF measurement process that could readily be incorporated into office visits and in field settings to screen all youth periodically could help identify those at increased risk.