Boutou AK; Daniil Z; Pitsiou G; Papakosta D; Kioumis I; Stanopoulos I;

Respiratory medicine [Respir Med] 2020 Apr 02; Vol. 167, pp. 105953. Date of Electronic Publication: 2020 Apr 02.

Asthma is one of the most common respiratory disorders, characterized by fully or largely reversible airflow limitation. Asthma symptoms can be triggered or magnified during exertion, while physical activity limitation is often present among asthmatic patients. Cardiopulmonary exercise testing (CPET) is a dynamic, non-invasive technique which provides a thorough assessment of exercise physiology, involving the integrative assessment of cardiopulmonary, neuromuscular and metabolic responses during exercise. This review summarizes current evidence regarding the utility of CPET in the diagnostic work-up, functional evaluation and therapeutic intervention among patients with asthma, highlighting its potential role for thorough patient assessment and physician clinical desicion-making.

Hedlund ER; Söderström L; Lundell B;

Cardiology in the young [Cardiol Young] 2020 Apr 17, pp. 1-7. Date of Electronic Publication: 2020 Apr 17.

Objective: To evaluate heart rate against workload and oxygen consumption during exercise in Fontan patients.
Method: Fontan patients (n = 27) and healthy controls (n = 25) underwent cardiopulmonary exercise testing with linear increase of load. Heart rate and oxygen uptake were measured during tests. Heart rate recovery was recorded for 10 minutes.
Results: Heart rate at midpoint (140 ± 14 versus 153 ± 11, p < 0.001) and at maximal effort (171 ± 14 versus 191 ± 10 beats per minute, p < 0.001) of test was lower for patients than controls. Heart rate recovery was similar between groups. Heart rate in relation to workload was higher for patients than controls both at midpoint and maximal effort. Heart rate in relation to oxygen uptake was similar between groups throughout test. Oxygen pulse, an indirect surrogate measure of stroke volume, was reduced at maximal effort in patients compared to controls (6.6 ± 1.1 versus 7.5 ± 1.4 ml·beat-1·m-2, p < 0.05) and increased significantly less from midpoint to maximal effort for patients than controls (p < 0.05).
Conclusions: Heart rate is increased in relation to workload in Fontan patients compared with controls. At higher loads, Fontan patients seem to have reduced heart rate and smaller increase in oxygen pulse, which may be explained by inability to further increase stroke volume and cardiac output. Reduced ability to increase or maintain stroke volume at higher heart rates may be an important limiting factor for maximal cardiac output, oxygen uptake, and physical performance.

Kuint R; Berkman N; Nusair S;

F1000Research [F1000Res] 2019 Sep 19; Vol. 8, pp. 1661. Date of Electronic Publication: 2019 Sep 19 (Print Publication: 2019).

Background: Air trapping and gas exchange abnormalities are major causes of exercise limitation in chronic obstructive pulmonary disease (COPD). During incremental cardiopulmonary exercise testing, ventilatory equivalents for carbon dioxide (V _E /VCO ₂ ) and oxygen (V _E /VO ₂ ) may be difficult to identify in COPD patients because of limited ventilatory compensation capacity. Therefore, we aimed to detect a possible correlation between the magnitude of ventilation augmentation, as manifested by increments in ventilatory equivalents from nadir to peak effort values and air trapping, detected with static testing.
Methods: In this observational study, we studied data obtained previously from 20 COPD patients who, during routine follow-up, underwent a symptom-limited incremental exercise test and in whom a plethysmography was obtained concurrently. Air trapping at rest was assessed by measurement of the residual volume (RV) to total lung capacity (TLC) ratio (RV/TLC). Gas exchange data collected during the symptom-limited incremental cardiopulmonary exercise test allowed determination of the nadir and peak effort values of V _E /VCO ₂ and V _E /VO ₂ , thus enabling calculation of the difference between peak effort value and nadir values of  V _E /VCO ₂ and V _E /VO ₂ , designated ΔV _E /VCO ₂ and ΔV _E /VO ₂ , respectively.
Results: We found a statistically significant inverse correlation between both ΔV _E /VCO ₂ (r = -0. 5058, 95% CI -0.7750 to -0.08149, p = 0.0234) and ΔV _E /VO ₂ (r = -0.5588, 95% CI -0.8029 to -0.1545, p = 0.0104) and the degree of air trapping (RV/TLC). There was no correlation between                ΔV _E /VCO ₂ and peak oxygen consumption, forced expiratory volume in the first second, or body mass index.
Conclusions: The ventilatory equivalents increment to compensate for acidosis during incremental exercise testing was inversely correlated with air trapping (RV/TLC) and may be a candidate prognostic biomarker.

Powell AW; Veldtman G;

The Canadian Journal of Cardiology [Can J Cardiol] 2019 Nov 15. Date of Electronic Publication: 2019 Nov 15.

Background: Patients with univentricular physiology palliated with the Fontan operation have multiple late cardiovascular and extracardiac complications, including autonomic dysfunction. Despite the observation, little is known about autonomic function driving exercise-related heart rate responses in Fontan patients and whether dominant ventricle subtype or underlying cardiac anatomy affects heart rate responses during exercise.
Methods: We performed a retrospective chart review of all single ventricle patients palliated with a Fontan operation who underwent a maximal effort cardiopulmonary exercise test at Cincinnati Children’s Hospital Medical Center from 2013 to 2018.
Results: One hundred and three Fontan patients aged 16.7 ± 5.5 years were included in this study. Although both the systemic right (n = 38) and systemic left (n = 65) ventricle groups demonstrated chronotropic incompetence, there were no differences between the groups in maximal heart rate (167.5 ± 17.4 vs 169.6 ± 20.9 bpm, P = 0.59), heart rate reserve (87.3 ± 22.6 vs 96.8 ± 25.7, P = 0.06) nor chronotropic index (70 ± 13% vs 74 ± 20%, P = 0.19). In addition, there were no differences between the groups in heart rate recovery at 1, 3, 5, and 10 minutes. Interestingly, patients with hypoplastic left heart syndrome (n = 34) had lower heart rate reserve (84.76 ± 22.8 vs 96.38 ± 26.75, P = 0.04) and chronotropic index (70.5 ± 12.5% vs 76.3 ± 13.2%, P = 0.04) compared with patients with tricuspid atresia (n = 42).
Conclusions: Fontan patients commonly have chronotropic incompetence, diminished heart rate reserve but with preserved heart rate recovery. Although there is overall no difference in chronotropy in Fontan patients based on dominant systemic ventricle, there is a difference between patients with hypoplastic left heart syndrome and those with tricuspid atresia.

Yokote T; Koga H; Eriguchi K; Imamura Y;

Journal of physical therapy science [J Phys Ther Sci] 2020 Apr; Vol. 32 (4), pp. 265-268. Date of Electronic Publication: 2020 Apr 02.

[Purpose] The mortality rate increases when peak oxygen uptake is less than 5 metabolic equivalents, and peak oxygen uptake correlates with knee extensor muscle strength. This study aimed to determine the knee extensor muscle strength at peak oxygen uptake corresponding to 5 metabolic equivalents.
[Participants and Methods] We enrolled 45 consecutive patients (29 males and 16 females; average age, 63.6 ± 13.7 years) with heart disease receiving outpatient rehabilitation with us. We performed cardiopulmonary exercise testing with a bicycle ergometer to measure peak oxygen uptake. We investigated the relationship between peak oxygen uptake and isometric knee extensor muscle strength divided by the body weight (kgf/kg). The cutoff value for knee extensor muscle strength with peak oxygen uptake corresponding to 5 metabolic equivalents was calculated.
[Results] Knee extensor muscle strength was significantly positively associated with peak oxygen uptake. The cutoff value for knee extensor muscle strength at peak oxygen uptake corresponding to 5 metabolic equivalents was 0.46 kgf/kg.
[Conclusion] In this study, the cutoff value for knee extensor muscle strength for achieving peak oxygen uptake corresponding to 5 metabolic equivalents in patients with heart disease was 0.46kgf/kg.

Takken T; Sonbahar Ulu H; Hulzebos EH;

Expert review of respiratory medicine [Expert Rev Respir Med] 2020 Apr 07. Date of Electronic Publication: 2020 Apr 07.

Introduction : Cardiopulmonary exercise testing (CPET) quantitates and qualitates the integrated physiological response of a person to incremental exercise and provides additional information compared to static lung function tests alone.
Areas covered : This review covers rationale for the use of CPET parameters beyond the usual parameters like peak oxygen uptake and peak minute ventilation in children with respiratory disease.
Expert opinion : CPET provides a wealth of data from rest, submaximal and maximal exercise and data during recovery from exercise. In this review an interpretative approach is described for analyzing CPET data in children with respiratory disease.

Popovic D; Arena R; Jakovljevic D; Ristic A; Guazzi M;

Clinical cardiology [Clin Cardiol] 2020 Apr 09. Date of Electronic Publication: 2020 Apr 09.

Background: Continued high mortality in heart failure patients indicates the need for additional methods of risk stratification and phenotyping.
Hypothesis: We hypothesized that ventricular arrhythmias that do not meet test-termination criteria (non-terminating ventricular arrhythmias [NTVA]) during cardiopulmonary exercise testing (CPET) may help in phenotyping disease severity and prognosis in heart failure with reduced (HFrEF) and midrange (HFmrEF)/preserved (HFpEF) left ventricular ejection fraction (LVEF).
Methods: About 319 patients with heart failure (199 HFrEF; 80 HFmrEF; 41 HFpEF) underwent CPET. Tricuspid annular plane systolic excursion (TAPSE) and pulmonary artery systolic pressure (PASP) were measured by echocardiography. B-type natriuretic peptide (BNP) at rest and peak exercise was also determined. The patients were tracked for primary (cardiac death) and secondary composite outcomes (all-cause death, heart transplantation/left ventricular assist device implantation, hospitalization for cardiac reasons).
Results: Forty-seven (15%) of the patients demonstrated NTVA during CPET, regardless of coronary artery disease prevalence. Patients without arrhythmias had a significantly higher LVEF (P < .05), TAPSE/PASP ratio (P < .001), peak oxygen consumption (P < .01), lower resting and peak BNP (P < .001), and the minute ventilation/carbon dioxide production slope (P < .001) compared to those with NTVA. Seventy-one patients died during the tracking period, 54 for cardiac reasons. NTVA during CPET was a significant predictor of primary and secondary outcomes in the total heart failure cohort (HR: 5.3, 3.7; 95% CI: 3.1-9.1, 2.4-5.5; P < .001, respectively), as well as in subgroups categorized according to reduced and middle-range/preserved LVEF (P < .001).
Conclusion: Exercise-induced ventricular arrhythmias that do not reach test-termination criteria are nonetheless indicative of an advanced disease severity phenotype and worse prognosis.

Pymer, S.  Nichols, S. Prosser, J. Birkett, S. Carroll, S. Ingle, L.

Eur J Prev Cardiol. 2020;27(6):579-589.

BACKGROUND: In the United Kingdom (UK), exercise intensity is prescribed from a fixed percentage range (% heart rate reserve (%HRR)) in cardiac rehabilitation programmes. We aimed to determine the accuracy of this approach by comparing it with an objective, threshold-based approach incorporating the accurate determination of ventilatory anaerobic threshold (VAT). We also aimed to investigate the role of baseline cardiorespiratory fitness status and exercise testing mode dependency (cycle vs. treadmill ergometer) on these relationships.

DESIGN AND METHODS: A maximal cardiopulmonary exercise test was conducted on a cycle ergometer or a treadmill before and following usual-care circuit training from two separate cardiac rehabilitation programmes from a single region in the UK. The heart rate corresponding to VAT was compared with current heart rate-based exercise prescription guidelines.

RESULTS: We included 112 referred patients (61 years (59-63); body mass index 29 kg.m(-2) (29-30); 88% male). There was a significant but relatively weak correlation (r = 0.32; p = 0.001) between measured and predicted %HRR, and values were significantly different from each other (p = 0.005). Within this cohort, we found that 55% of patients had their VAT identified outside of the 40-70% predicted HRR exercise training zone. In the majority of participants (45%), the VAT occurred at an exercise intensity <40% HRR. Moreover, 57% of patients with low levels of cardiorespiratory fitness achieved VAT at <40% HRR, whereas 30% of patients with higher fitness achieved their VAT at >70% HRR. VAT was significantly higher on the treadmill than the cycle ergometer (p < 0.001).

CONCLUSION: In the UK, current guidelines for prescribing exercise intensity are based on a fixed percentage range. Our findings indicate that this approach may be inaccurate in a large proportion of patients undertaking cardiac rehabilitation.

Philip Maffetone , Paul B. Laursen

Front.Physiol. 02 April 2020         https://doi.org/10.3389/fphys.2020.00296

The earliest humans relied on large quantities of metabolic energy from the oxidation of fatty acids to develop larger brains and bodies, prevent and reduce disease risk, extend longevity, in addition to other benefits. This was enabled through the consumption of a high fat and low-carbohydrate diet (LCD). Increased fat oxidation also supported daily bouts of prolonged, low-intensity, aerobic-based physical activity. Over the past 40-plus years, a clinical program has been developed to help people manage their lifestyles to promote increased fat oxidation as a means to improve various aspects of health and fitness that include reducing excess body fat, preventing disease, and optimizing human performance. This program is referred to as maximum aerobic function, and includes the practical application of a personalized exercise heart rate (HR) formula of low-to-moderate intensity associated with maximal fat oxidation (MFO), and without the need for laboratory evaluations. The relationship between exercise training at this HR and associated laboratory measures of MFO, health outcomes and athletic performance must be verified scientifically.

Dawkins C; Hollingsworth AC; Milburn S; Cheesman M; Walker P; Mofidi R;

The Journal of cardiovascular surgery [J Cardiovasc Surg (Torino)] 2020 Apr 01. Date of Electronic Publication: 2020 Apr 01.

Background: Vascular Services Quality Improvement Program (VSQIP) was introduced to reduce mortality from elective repair of AAA in the United Kingdom. This study examines the differences in perioperative mortality and postoperative survival between men and women following elective repair of AAAs in the 10 years after implementation of the (VSQIP).
Methods: Consecutive patients who underwent elective repair of AAA between 1stJanuary 2008 and 31st March 2018 were included. All patients were assessed using the nationally agreed VSQIP pathway which involved cardiopulmonary exercise testing as well as contrast enhanced CT scan of aorta and multidisciplinary assessment to plan each treatment. CT scans were examined to assess the morphology of AAA. Patients were stratified by age, gender, AAA morphology and preoperative anaerobic threshold. Postoperative survival was assessed using Kaplan-Meier analysis. Cox regression analysis was used to determine predictors of postoperative mortality.
Results: A total of 702 patients underwent elective repair of AAA of whom 632 were men and 70 were women. The mean age of study cohort was 73.5 years (std. dev: 7.3) and mean AAA diameter was 62 mm (std. dev.: 9.9). Two hundred and forty four patients underwent open repair, 402 underwent standard infra renal Endovascular Aneurysm Repair (EVAR) and 56 underwent complex EVAR with perioperative and 30 day mortality of 1.13%. No significant difference was observed in perioperative/30 day mortality between men and women (χ2=0.06, P=0.81). Anaerobic threshold< 8 (HR: 95%CI: 0.68 (0.51-0.92)), complex aneurysm morphology (HR: 95%CI: 1.7 (1.39-2.19)) risk category (HR: 95%CI: 1.89 (1.48-2.42)) and patients age (HR: 95%CI: 1.41 (1.13-1.89)) were independent risk factor for mortality following repair of AAA, whilst female gender [(HR: 95%CI: 0.89 (0.54-1.48)] and AAA size [(HR: 95%CI: 1.01 (0.84-1.22)] were not. There was no difference in post- operative survival between men and women who underwent elective repair of AAA (Log rank: 1.82 P=0.61).
Conclusions: Following the implementation of VSQIP female gender is no longer a significant risk factor for perioperative mortality or reduced survival following elective repair of large asymptomatic AAA.