Maximal Cardiopulmonary Exercise Testing Research Articles

Intrapulmonary distribution of blood flow during exercise in pulmonary hypertension assessed by a new combination technique.

Hyperventilation and inadequate cardiac output (CO) increase are the main causes of exercise limitation in pulmonary hypertension (PH). Intrapulmonary blood flow partitioning between ventilated and unventilated lung zones is unknown. Thoracic impedance cardiography and inert gas rebreathing have been both validated in PH patients for non-invasive measurement of CO and pulmonary blood flow (PBF), respectively. This study sought to evaluate CO behaviour in PH patients during exercise and its partitioning between ventilated and unventilated lung areas, in parallel with ventilation partitioning between ventilated and unventilated lung zones. Eighteen PH patients (group 1 or 4) underwent a cardiopulmonary exercise test (CPET) with a three-step loaded workload protocol. The steps occurred at 0%, 20%, 40%, and 60% of peak workload reached during a preliminary maximum CPET. Ventilatory parameters, arterial blood gases, CO, PBF, and intrapulmonary shunt (calculated as the difference between CO and PBF) were obtained at each step, combining thoracic impedance cardiography and an inert gas rebreathing technique. Dead space ventilation observed throughout the exercise was about 40% of total ventilation. A progressive increase of CO from 4.86 ± 1.24 L/min (rest) to 9.41 ± 2.63 L/min (last step), PBF from 3.81 ± 1.41 L/min to 7.21 ± 2.93 L/min, and intrapulmonary shunt from 1.05 ± 0.96 L/min to 2.21 ± 2.28 L/min was observed. Intrapulmonary shunt was approximately 20% of CO at each exercise step. Although the study population was small, the combined non-invasive CO measurement seems a promising tool for deepening our knowledge of lung exercise haemodynamics in PH patients. This technique could be applied in future studies to evaluate PH treatment influences on CO partitioning, since a secondary increase of intrapulmonary shunt is undesirable.

A remote monitoring-enabled home exercise prescription for patients with interstitial lung disease at risk for exercise-induced desaturation

RationaleAlternatives to center-based pulmonary rehabilitation are needed to improve patient access to this important therapy. A critical challenge to overcome is how to maximize safety of unsupervised exercise for at-risk patients. We investigated if a novel remote monitoring-enabled mobile health (mHealth) program is safe, feasible, and effective for patients who experience exercise-induced hemoglobin desaturation. MethodsAn interstitial lung disease (ILD) commonly associated with pronounced exercise desaturation was investigated - the rare, female-predominant ILD lymphangioleiomyomatosis (LAM). Over a 12-week program, hemoglobin saturation (SpO2) was continuously recorded during all home exercise sessions. Intervention effects were assessed with 6-min walk test (6MWT), maximal cardiopulmonary exercise test (CPET), lower extremity computerized dynamometry, pulmonary function tests, and health-related quality of life (QoL) surveys. Safety was assessed by blood biomarkers of systemic inflammation and cardiac wall stress, and incidence of adverse events. ResultsFifteen LAM patients enrolled and 14 completed the intervention, with high adherence to aerobic (87 ± 15%) and strength (87 ± 12%) training components. An innovative characterization of exercise training SpO2 revealed that while mild-to-moderate desaturation was common during home workouts, participants were able to self-adjust exercise intensity and supplemental oxygen levels to maintain recommended exercise parameters. Significant improvements included 6MWT distance (+36 ± 34 m, p = 0.003), CPET time (p = 0.04), muscular endurance (p = 0.008), QoL (p = 0.009 to 0.03), and fatigue (p = 0.001 to 0.03). Patient acceptability and satisfaction indicators were high, blood biomarkers remained stable (p > 0.05), and no study-related adverse events occurred. ConclusionA remote monitoring-enabled home exercise program is a safe, feasible, and effective approach even for patients who experience exercise desaturation.

Cardiopulmonary exercise testing of patients with metastatic castrate-resistant prostate cancer as screening for vigorous exercise medicine prescription.

80 Background: Exercise is recommended for patients with prostate cancer to manage treatment adverse effects, improve quality of life and potentially influence cancer-specific outcomes. Men with advanced prostate cancer and metastatic disease may be at increased risk of cardiac events due to their cancer treatment and comorbidities. The aim of this study was to assess the safety and efficacy of cardiopulmonary exercise testing (CPET) for assessing cardiorespiratory capacity and risk screening of patients with metastatic castrate-resistant prostate cancer (mCRPC) prior to engaging in a vigorous program of exercise medicine. Methods: Experimental design was a cross-sectional analysis of screening CPET’s from a Phase III Randomised Controlled Trial (INTERVAL-GAP4) within the clinical setting involving men with mCRPC. Testing incorporated medically supervised, symptom limited, CPET with electrocardiogram (ECG) performed on a cycle ergometer until volitional exhaustion or maximal oxygen uptake peak (V02.PEAK) attained. Outcome Measurements included safety (incidence and severity of adverse events), feasibility (completion of CPET) and efficacy (performance outcomes, screen-fails, and cardiac pathology). Descriptive statistics were calculated as mean and standard deviation. Results: 104 men (age 71.5 ± 8.4 years) with mCRPC completed a medically supervised CPET. Of these, 96 patients (92.3%) met the criterion for V02.PEAK attainment and were randomised to the INTERVAL-GAP4 trial, with 8 (7.7%) CPET screen-fails. Four positive cardiac abnormalities (3.8%) were observed, with these patients referred to a cardiologist for further assessment. Referred patients were all cleared to participate in vigorous exercise with no clinically significant cardiovascular disease or were determined to have newly diagnosed and subsequently controlled cardiovascular disease. Average V02.PEAK was 1.72 ± 0.51 L.min-1 absolute and 18.96 ± 5.30 mL.kg-1.min-1 relative which is in the 10-15th percentile for healthy men of this age. Maximal heart rate achieved was 141 ± 20 bpm at a maximal workload of 128 ± 40 W. There were no cardiac events or any other exercise-related adverse events during the testing. Conclusions: Maximal CPET is safe for men with advanced prostate cancer. CPET with ECG is also an effective cardiac stress screening tool prior to engaging in a vigorous exercise medicine program to detect underlying cardiovascular health issues. Further, results from CPET can be used to inform appropriate exercise prescription individualised to the patient. Clinical trial information: NCT02730338 .

Reference Values of Cardiopulmonary Exercise Test Parameters in the Contemporary Paediatric Population

BackgroundThe evaluation of health status by cardiopulmonary exercise test (CPET) has shown increasing interest in the paediatric population. Our group recently established reference Z-score values for paediatric cycle ergometer VO2max, applicable to normal and extreme weights, from a cohort of 1141 healthy children. There are currently no validated reference values for the other CPET parameters in the paediatric population. This study aimed to establish, from the same cohort, reference Z-score values for the main paediatric cycle ergometer CPET parameters, apart from VO2max.ResultsIn this cross-sectional study, 909 healthy children aged 5–18 years old underwent a CPET. Linear, quadratic, and polynomial mathematical regression equations were applied to identify the best CPET parameters Z-scores, according to anthropometric parameters (sex, age, height, weight, and BMI). This study provided Z-scores for maximal CPET parameters (heart rate, respiratory exchange ratio, workload, and oxygen pulse), submaximal CPET parameters (ventilatory anaerobic threshold, VE/VCO2 slope, and oxygen uptake efficiency slope), and maximum ventilatory CPET parameters (tidal volume, respiratory rate, breathing reserve, and ventilatory equivalent for CO2 and O2).ConclusionsThis study defined paediatric reference Z-score values for the main cycle ergometer CPET parameters, in addition to the existing reference values for VO2max, applicable to children of normal and extreme weights. Providing Z-scores for CPET parameters in the paediatric population should be useful in the follow-up of children with various chronic diseases. Thus, new paediatric research fields are opening up, such as prognostic studies and clinical trials using cardiopulmonary fitness outcomes.Trial registration NCT04876209—Registered 6 May 2021—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04876209.

Exercise intensity domains determined by heart rate at the ventilatory thresholds in patients with cardiovascular disease: new insights and comparisons to cardiovascular rehabilitation prescription recommendations

ObjectivesTo compare the elicited exercise responses at ventilatory thresholds (VTs: VT1 and VT2) identified by cardiopulmonary exercise testing (CPET) in patients with cardiovascular disease (CVD) with the guideline-directed exercise intensity...

An Examination of Heart Rate Variability at Anaerobic Threshold and Respiratory Compensation Points During Cardiopulmonary Exercise Test

The aim of this study is to examine the changes in HRV values before, during (at AT and RC) and after maximal incremental cardiopulmonary exercise test. The sample comprised 121 healthy men who recreational do exercise 2-3 days a week. (age: 30.5 ± 4.6 years, height: 177.8 ± 6.1 cm; weight: 80.2 ± 10.2 kg). Anthropometric measurements were measured by using body analyzer, and aerobic capacities of participants were measured by using the cardiopulmonary exercise test via the Bruce protocol. According to this, heart rate variability recordings were taken at seven stages during the cardiopulmonary exercise test: before the test (1), at the beginning of the test (2), between the beginning of the test and the anaerobic threshold (3), at the anaerobic threshold (4), between the anaerobic threshold and the respiratory threshold (5), at the respiratory threshold (6), and finally (7), 30 seconds after the cardiopulmonary exercise test. Repeated measures analysis of variance (ANOVA) was used to compare the HRV values obtained from the test stages. In conclusion, using a gas analyzer during cardiovascular exercise testing, HRV values (MeanRR, SDNN, RMSSD, LFnu) determined at seven stages continue to decrease from the beginning. A rest period of 30 seconds (passive rest) immediately after completing the exercise does not seem to be sufficient for recovery. According to the results of this study, it can be considered that the sympathetic nervous system activity (LFnu) exhibits a more pronounced appearance at threshold zones.

Maximal cardiopulmonary exercise testing in laryngectomised patients using different heat and moisture exchangers - feasibility and exercise responses.

After laryngectomy, the breathing resistance of heat and moisture exchangers may limit exercise capacity. Breathing gas analysis during cardiopulmonary exercise testing is not possible using regular masks. This study tested the feasibility of cardiopulmonary exercise testing with a heat and moisture exchanger in situ, using an in-house designed connector. Additionally, we explored the effect of different heat and moisture exchanger resistances on exercise capacity in this group. Ten participants underwent two cardiopulmonary exercise tests using their daily life heat and moisture exchanger (0.3 hPa or 0.6 hPa) and one specifically developed for activity (0.15 hPa). Heat and moisture exchanger order was randomised and blinded. All participants completed both tests. No (serious) adverse events occurred. Only four subjects reached a respiratory exchange ratio of more than 1.1 in at least one test. Maximum exercise levels using heat and moisture exchangers with different resistances did not differ. Cardiopulmonary exercise testing in laryngectomees with a heat and moisture exchanger is feasible; however, the protocol does not seem appropriate to reach this group's maximal exercise capacity. Lowering heat and moisture exchanger resistance does not increase exercise capacity in this sample.

Integrative Interpretation of Cardiopulmonary Exercise Tests for Cardiovascular Outcome Prediction: A Machine Learning Approach.

Integrative interpretation of cardiopulmonary exercise tests (CPETs) may improve assessment of cardiovascular (CV) risk. Here, we identified patient phenogroups based on CPET summary metrics and evaluated their predictive value for CV events. We included 2280 patients with diverse CV risk who underwent maximal CPET by cycle ergometry. Key CPET indices and information on incident CV events (median follow-up time: 5.3 years) were derived. Next, we applied unsupervised clustering by Gaussian Mixture modeling to subdivide the cohort into four male and four female phenogroups solely based on differences in CPET metrics. Ten of 18 CPET metrics were used for clustering as eight were removed due to high collinearity. In males and females, the phenogroups differed significantly in age, BMI, blood pressure, disease prevalence, medication intake and spirometry. In males, phenogroups 3 and 4 presented a significantly higher risk for incident CV events than phenogroup 1 (multivariable-adjusted hazard ratio: 1.51 and 2.19; p ≤ 0.048). In females, differences in the risk for future CV events between the phenogroups were not significant after adjustment for clinical covariables. Integrative CPET-based phenogrouping, thus, adequately stratified male patients according to CV risk. CPET phenomapping may facilitate comprehensive evaluation of CPET results and steer CV risk stratification and management.

IMPACT OF POST-COVID MENTAL STRESS DISORDERS ON BLOOD PRESSURE RESPONSE TO EXERCISE

Objective: Patients recovered from COVID-19 are at high risk of developing mental stress disorders over the long-term. Post-traumatical stress disorders (PTSD) are associated with increased BP and hypertension incidence. We tested the hypothesis that PTSD, occurring in patients after hospital discharge for severe COVID-19, is associated with an impaired BP response to exercise. Design and method: 108 patients previously hospitalized for severe COVID-19 were evaluated after 5 months from hospital discharge. A Revised Impact of Event Scale (IES-r) score>33 indicated probable COVID-related PTSDs All subjects underwent maximal cardio-pulmonary exercise test on a cycle ergometer with incremental ramp protocol. Submaximal BP was recorded after 4 minutes, at a workload threshold of 75W. Results: 95 subjects (mean age 58±10 years, 71% men) had complete data. Mean baseline BP was 128/82±12/11 mmHg. 51% were hypertensive. 32% had a IES-r score>33 (PTSD group). These patients were more frequently women (45% vs 20%, p = 0.01), whereas no differences in terms of age, BMI, hypertension history, other CV risk factors or diseases were found compared to non-PTSD group. Baseline BP did not differ between PTSD and non-PTSD groups (127/82±10/8 mmHg vs 129/82±15/9 mmHg, p = 0.43/0.88). By contrast, submaximal exercise SBP (eSBP) was increased in PTSD vs non-PTSD group (155±16 mmHg vs 146±14 mmHg, p<0.05). A strong sex-specific effect was found, being eSBP higher in PTSD vs non-PTSD women, but not in PTSD vs non-PTSD men (p for sex interaction = 0.01). Intrusion symptoms, such as unwanted and upsetting memories, nightmares and flashbacks, were more markedly associated with increased BP response to exercise. Conclusions: In people with mental stress disorders related to previous COVID-19 hospitalization, we showed increased submaximal BP during exercise. This finding showed a sex-specific association, being observed in women but not in men. Mental stress disorders could negatively impact on future CV risk in post-COVID-19 women through an exaggerated BP response to physical stressors.

Cardiorespiratory Fitness and Cardiac Magnetic Resonance Imaging in Childhood Acute Lymphoblastic Leukemia Survivors.

Childhood acute lymphoblastic leukemia survivors' anthracycline-induced cardiotoxicity could be prevented with good cardiorespiratory fitness levels and regular physical activity. This cross-sectional study aimed to assess the association between cardiorespiratory fitness and physical activity with cardiac magnetic resonance parameters. A total of 96 childhood acute lymphoblastic leukemia survivors underwent a maximal cardiopulmonary exercise test and answered physical activity questionnaires. We calculated the odds ratio of the preventive fraction of regular physical activity (≥150min/wk) and adequate cardiorespiratory fitness levels (above the median ≥31.4mL·kg-1·min-1) on cardiac magnetic resonance parameters (left ventricular [LV] and right ventricular [RV] morphological and functional parameters). An adequate cardiorespiratory fitness was associated with a significant preventive fraction for LV (up to 84% for LV end-diastolic volume) and RV volumes (up to 88% for RV end-systolic volume). The adjusted analyses highlighted a preventive fraction of 36% to 91% between an adequate cardiorespiratory fitness and LV and RV parameters, late gadolinium enhancement fibrosis, and cardiac magnetic resonance relaxation times. No associations were reported with regular physical activity. This study provides additional evidence regarding the benefits of an adequate cardiorespiratory fitness level for childhood cancer survivors' cardiac health.

Validity Study Comparing Polar Ignite’s® Estimated VO2max to Traditional Cardiopulmonary Exercise Testing in Normal Cardiac Anatomy & Fontan Pediatric Patients

Cardiorespiratory fitness as represented by maximum oxygen uptake, VO2max, is considered the best indicator for overall cardiovascular health. Fitness technology such as wrist worn devices, now allows for an easy method to monitor an individual’s VO2max. This study sought to compare the estimated VO2max measurements from the Polar Ignite (Polar Electro Oy, Kempele, Finland) fitness watch (Polar Ignite) against the gold standard, cardiopulmonary exercise testing (CPET) in normal cardiac anatomy and Fontan pediatric patients. This single-center, prospective study enrolled patients with normal cardiac anatomy and single ventricle patients with Fontan palliation (Fontan) between 13-21 years. The Polar Ignite was fastened on the patient’s right or left wrist while supine and estimated VO2max was generated based on a non-exercise test (Polar Fitness Test). A maximal voluntary CPET using the standard Bruce Treadmill Protocol was then completed. Measurements from the two tests were compared using the intraclass correlation coefficient (ICC), Pearson correlation coefficient and Bland-Altman method. Forty-seven patients were enrolled, including n=36 (77%) normal cardiac patients and n=11 (23%) Fontan patients. The majority of participants were white (n=41, 87%) and female (n=36, 66%). Patients were 15.3±1.9 years old, weighed 65.7±16.6 kg, and were 168.0±10.4 cm tall on average. The mean estimated Polar Ignite VO2max and peak CPET VO2 was 43.9±6.1 ml/kg/min vs 37.7±8.2 ml/kg/min, respectively in the normal cardiac group, and 42.6±3.9 ml/kg/min vs 22.6±5.6 ml/kg/min, respectively in the Fontan group. We found poor validity (ICC=0.21) and a weak correlation (r=0.31, p=0.07) between VO2max measured by the Polar Ignite and CPET in the normal cardiac group and poor validity (ICC=0.08) and strong correlation (r=0.84, p=0.001) in the Fontan group. In Bland-Altman analyses, the mean bias between VO2max as measured by the Polar Ignite and CPET was 6.85 ml/kg/min among the normal cardiac group and 20.05 ml/kg/min among the Fontan group. The Polar Ignite overestimated VO2max compared to CPET in both the normal cardiac and Fontan groups and cannot replace formal testing.

Deployed Veterans exhibit distinct respiratory patterns and greater dyspnea during maximal cardiopulmonary exercise: A case-control study.

Exertional dyspnea and exercise intolerance are frequently endorsed in Veterans of post 9/11 conflicts in Southwest Asia (SWA). Studying the dynamic behavior of ventilation during exercise may provide mechanistic insight into these symptoms. Using maximal cardiopulmonary exercise testing (CPET) to experimentally induce exertional symptoms, we aimed to identify potential physiological differences between deployed Veterans and non-deployed controls. Deployed (n = 31) and non-deployed (n = 17) participants performed a maximal effort CPET via the Bruce treadmill protocol. Indirect calorimetry and perceptual rating scales were used to measure rate of oxygen consumption ([Formula: see text]), rate of carbon dioxide production ([Formula: see text]), respiratory frequency (f R), tidal volume (VT), minute ventilation ([Formula: see text]), heart rate (HR), perceived exertion (RPE; 6-20 scale), and dyspnea (Borg Breathlessness Scale; 0-10 scale). A repeated measures analysis of variance (RM-ANOVA) model (2 groups: deployed vs non-deployed X 6 timepoints: 0%, 20%, 40%, 60%, 80%, and 100% [Formula: see text]) was conducted for participants meeting valid effort criteria (deployed = 25; non-deployed = 11). Significant group (η2partial = 0.26) and interaction (η2partial = 0.10) effects were observed such that deployed Veterans exhibited reduced f R and a greater change over time relative to non-deployed controls. There was also a significant group effect for dyspnea ratings (η2partial = 0.18) showing higher values in deployed participants. Exploratory correlational analyses revealed significant associations between dyspnea ratings and fR at 80% (R2 = 0.34) and 100% (R2 = 0.17) of [Formula: see text], but only in deployed Veterans. Relative to non-deployed controls, Veterans deployed to SWA exhibited reduced fR and greater dyspnea during maximal exercise. Further, associations between these parameters occurred only in deployed Veterans. These findings support an association between SWA deployment and affected respiratory health, and also highlight the utility of CPET in the clinical evaluation of deployment-related dyspnea in Veterans.

Respiratory exchange ratio overshoot during exercise recovery: a novel prognostic marker in heart failure

Abstract Funding Acknowledgements Type of funding sources: None. Background In recent years considerable new evidence has been added on the analysis of the recovery phase in patients with heart failure. Transient increases (overshoot) in respiratory gas variables have been observed during exercise recovery, but their clinical significance is not clearly understood. Respiratory Exchange Ratio (RER) at peak exercise (RER peak) is an objective index of exercise intensity. The overshoot phenomenon of the RER is commonly observed during recovery from maximal cardiopulmonary exercise testing (CPET) but initial studies have found a decreased RER-magnitude in patients with heart failure with reduced ejection fraction (HFrEF). Purpose To characterize the functional and prognostic significance of RER recovery kinetics in individuals with HFrEF. Methods This cross-sectional study included all patients with HFrEF who underwent functional evaluation with maximal CPET for the heart transplant checklist at the Sports and Exercise Medicine Division of the Padova University Hospital between January 2018 and December 2021. The presence of overshoot phenomena of different respiratory gas indices was evaluated during the recovery phase, focusing on the RER. The RER behaviour has been evaluated assessing the maximal value during recovery phase (RER max) and the magnitude of the RER overshoot (RER mag). Results 164 patients with HFrEF and 128 controls were included in the study. RER recovery parameters were significantly lower in patients with HFrEF compared to healthy subjects. The RER overshoot showed significant correlations with prognostically relevant CPET parameters and these RER metrics were significantly higher in patients presenting better ventilatory and Weber classes. 24 patients with HFrEF did not present a RER overshoot showing worse cardiorespiratory fitness and efficiency compared to patients with overshoot. Mean follow-up period was 2.57 years during which there were 55 first major cardiovascular events, 22 deaths, 21 heart transplants, and 9 ventricular assist device implantations. The absence of RER overshoot predicted major adverse cardiac events- and transplant-free survival in univariate and multivariate Cox regression analysis. Conclusions RER overshoot represents a new index to monitor respiratory gas kinetics during the recovery phase, since it is a feasible and reproducible parameter for clinical practice. A reduced overshoot or its absence are significantly associated with functional impairment, cardiorespiratory inefficiency and worse prognosis. Thus, the evaluation of the respiratory gas indices during recovery from maximal CPET should be included in routine test interpretation, particularly for patients with HFrEF.

Acute effects of a maximal cardiopulmonary exercise test on cardiac hemodynamic and cerebrovascular response and their relationship with cognitive performance in individuals with type II diabetes

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Mirella and Lino Saputo Research Chair in Cardiovascular Diseases and the Prevention of Cognitive Decline from Université de Montréal at the Montreal Heart Institute. Montreal Heart Institute and the EPIC Center Foundations. FB are financially supported by a grant from the Fonds de Recherche du Québec – Santé (FRQ-S). Background/Introduction Cardiovascular and cerebrovascular disease are prevalent in type 2 diabetes (T2D) patient. Among people older than 70 years with T2D, up to 45% of might have cognitive dysfunction. Cardiorespiratory fitness (V̇O2peak) correlate with cognitive performances in healthy subjects, older adults, and people with CV diseases. The relationship between cognitive functions, V̇O2peak, cardiac output and cerebral oxygenation/perfusion responses during exercise has not been studied in patients with T2D. Studying cardiac and cerebrovascular hemodynamic responses during cardiopulmonary maximal exercise test (CPET) and its recovery phase and their relationship with cognition could be useful to detect patients at greater risk of future cognitive dysfunction. Purpose 1) To compare cerebral oxygenation/perfusion during a CPET and its post-exercise period (recovery), cognitive performances in T2D patients to those in healthy controls. 2) To examine if V̇O2peak, cardiac and cerebral hemodynamic are related to cognitive performances. Methods Nineteen T2D patients (61.9±7 years) and 22 healthy controls (HC) (61.8±10 years) were evaluated using a maximal CPET with impedance cardiography and cerebral oxygenation/perfusion (near-infrared spectroscopy) measure. The neuropsychological test battery evaluated short-term and working memory, processing speed, executive functions, and long-term verbal memory. Results T2D patients add a lower O2peak values compared to HC (34.5±5.6 vs 46.4±7.6 mL.kgFFM.min p<0.001). Peak cardiac index are also lowered compared to HC (p<0.05). Systemic vascular resistance index and systolic blood pressure at peak exercise were higher in T2D (p=0.005). Cerebral deoxyhemoglobin (HHb) during the 1st and 2nd min of the recovery remains significantly higher in HC compared to T2D (p<0.05). Executive functions were significantly lower in T2D patients compared to HC (p=0.016). Processing speed, working and verbal memory were similar in both groups. Total haemoglobin (tHb) during exercise and recovery, and oxyhemoglobin (O2Hb) during recovery only negatively correlated with executive function (p<0.05) in T2D patients (lower tHb values were associated with slower response times). Conclusion In addition to a reduced V̇O2peak and elevated vascular resistance, T2D patients showed a reduced cerebral O2Hb and HHb during early recovery (0 – 2 min) after peak exercise and a lower cognitive performance in executive function compared to healthy controls. Cerebrovascular responses with exercise and during the recovery phase could be a biological marker of cognitive impairment in T2D.

Maximal functional capacity in subjects with isolated left bundle branch block: a pilot study

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Sociedad Española de Cardiología. Background Left bundle branch block (LBBB) has been commonly associated with adverse cardiovascular (CV) events, but the effect of an isolated LBBB on maximal functional capacity is not well characterized. Purpose To evaluate maximal functional capacity in adults with isolated LBBB and compare it to healthy population-derived predicted values (adjusted for sex, age, weight, and height). Methods This descriptive pilot study included subjects with isolated LBBB derived from outpatient clinics of two academic hospitals. All subjects underwent maximal cardiopulmonary exercise testing (CPET) and a Global Physical Activity Questionnaire (GPAQ). The primary endpoint was to evaluate maximal functional capacity according to population-derived predicted values of peak oxygen consumption (peakVO2): pp-peakVO2. The secondary endpoint was to evaluate adverse CV events (CV deaths or hospitalizations) at follow-up. Results A total of 27 (18 women and 9 men) participants were included. The median (interquartile range) age of the sample and time to screening from the first LBBB diagnosis were 62 (51-71) and 3.4 (1.1-8.4) years, respectively. The results of the GPAQ score showed that 19 patients were highly active, and 8 were moderately active. The median of peakVO2 and pp-peakVO2 were 19.3 (15-22.5) mL/kg/min and 88 (79.3-104.4) %, respectively. There were no adverse CV events at a median follow-up after CPET of 3.1 (2.7-3.4) years. Conclusion In this pilot study, adults with isolated LBBB showed reduced maximal functional capacity, despite the absence of cardiac disease and a baseline moderate to highly active lifestyle.

Determinants of cardiopulmonary exercise test responses in hypertrophic cardiomyopathy

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Exercise capacity and ventilatory efficiency are often altered in hypertrophic cardiomyopathy (HCM) and several factors have been advocated as possible causes. Aim This study investigates the determinants of cardiopulmonary exercise test (CPET) prognostic markers for HCM (VO2Peak, VE/VCO2 Slope and PETCO2 apex), by considering echocardiographic and cardiac magnetic resonance (CMR) parameters. Secondly, it scopes if myocardial fibrosis at CMR leads to clinical and functional differences. Methods 64 patients with HCM underwent a clinical assessment, including maximal CPET, echocardiography, and CMR. Exclusion criteria were the corrective surgery for cardiac hypertrophy and heart failure stage. Results The study included 66% males, age 40±17 years, NYHA class I or II 91%. Mean left ventricle (LV) ejection fraction was 63,8±7,7%, with a mean LV maximal wall thickness (MVT) of 20,2±5,6 mm; LVOT gradient was >30mmHg in 14% of patients. Late gadolinium enhancement (LGE) was described in 70,3% of cases with a mean LGE extension on bullseye plot of 11%. 39% of patients had a VO2 peak <80% of predicted, 35% a reduced PETCO2 apex and 26% an increased VE/VCO2 Slope. At the stepwise multivariate analysis, age (β=-0,33; p=0,00), BMI (β=-0,80; p=0,002), systolic blood pressure increase (β=0,22; p=0,02), left atrial volume (β=-0,15; p=0,02) and BB therapy (β=-0,45; p=0,00) were independently associated with VO2 peak (R2-adjusted index 0,95). Concerning ventilatory efficiency, sex (β=-0,41; p=0,03), left atrial volume (β=0,46; p=0,01) and LGE extension (β=0,33; p=0,01) were independently associated with VE/VCO2 Slope (R2-adjusted index 0,46). Similar data, with reversed correlations, emerged for PETCO2 apex. Patients with LGE had a LV mass index (mean 104,6 vs 82,7 g/m2, p=0,04), MWT (mean 21,8 vs 16,2 mm, p=0,00) and diastolic function (mean E/e’ 13,4 vs 10,0, p=0,01) worse that the counterpart. No differences were found in sex, age, therapy, CPET parameters and arrhythmic burden. BB+ patients were older, had more LV hypertrophy, worse diastolic parameters, and functional capacity while ventilatory efficiency was similar. Conclusions This study supports previous data about VO2 peak determinants. The correlation between the extension of the LGE and ventilatory efficiency in patients with HCM is an original finding. It confirms the pathophysiological explanation of a lung ventilation/perfusion mismatch due to the increased left atrium pressure that is secondary to a more severe LV diastolic disfunction in patients with LGE. The reduced VO2 in BB+ compared to BB- patients is not inferable given the different age and severity of disease. Moreover, the negative chronotropic effect of BB during exercise prolongs the diastolic filling time, thus, improving stroke volume and alleviating the LV filling pressures, thus normalising, in the less advanced stages of pathology, the ventilatory efficiency in HCM patients.

Estimating cardiorespiratory fitness in heart failure patients with self-reported questionnaires

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiorespiratory fitness (CRF), assessed by peak oxygen uptake (VO2peak), is a powerful predictor of cardiovascular morbidity and mortality. However, performance of a cardiopulmonary exercise test (CPET) is often not feasible or desirable in (older) frail patients, because of physical limitations, transport difficulties, costs and the additional exposure to risks. Other CRF assessment tools, such as questionnaires, are potential alternatives, but have not been validated in frail elderly populations with chronic cardiovascular disease. Purpose The purpose of this study was to investigate the accuracy of two self-reported questionnaires, the FitMáx©-questionnaire and The Fitness Calculator, for assessment of CRF in chronic heart failure (CHF) patients. Methods CHF patients referred for CPET as part of a cardiac rehabilitation programme were eligible for the study. VO2peak was measured with a symptom limited maximal CPET. Participants completed two questionnaires to estimate VO2peak: the FitMáx-questionnaire and The Fitness Calculator. The FitMáx-questionnaire consists of three questions on walking, cycling and climbing stairs [1], and The Fitness Calculator is based on the HUNT3 study [2] and is currently advised by the American heart association as a non-exercise estimate for CRF [3]. Results 29 CHF patients (21 men, 64.2 years ± 12.0) were included with mean VO2peak of 15.7 ± 4.2 mL/kg/min at CPET. Correlation analysis indicated a moderate association between VO2peak assessed by the FitMáx-questionnaire and measured by CPET (r = 0.52) with a mean bias of 1.7 mL/kg/min (95% CI -6.0 – 9.4, p = 0.03). No association was found between VO2peak assessed by CPET and The Fitness Calculator (r = 0.24), mean bias 14.6 mL/kg/min (95% CI -0.5 – 29.7, p <.01). Conclusion The FitMáx©-questionnaire is a moderately accurate tool for estimating CRF in the CHF population. For use in individual patients, efforts should be made to improve the accuracy in this specific patient group. To establish its clinical utility, additional research is needed to evaluate its reproducibility and sensitivity to detect interventional changes in this population.

Cardiovascular implications and physical activity in middle-aged and older adults with a history of COVID-19 (CV COVID): a protocol for a randomised controlled trial

BackgroundThe clinical manifestation of COVID-19 is associated with infection and inflammation of the lungs, but there is evidence to suggest that COVID-19 may also affect the structure and function of the cardiovascular system. At present, it is not fully understood to what extent COVID-19 impacts cardiovascular function in the short- and long-term following infection. The aim of the present study is twofold: (i) to define the effect of COVID-19 on cardiovascular function (i.e. arterial stiffness, cardiac systolic and diastolic function) in otherwise healthy individuals and (ii) to evaluate the effect of a home-based physical activity intervention on cardiovascular function in people with a history of COVID-19.MethodsThis prospective, single-centre, observational study will recruit 120 COVID-19-vaccinated adult participants aged between 50 and 85 years, i.e. 80 with a history of COVID-19 and 40 healthy controls without a history of COVID-19. All participants will undergo baseline assessments including 12-lead electrocardiography, heart rate variability, arterial stiffness, rest and stress echocardiography with speckle tracking imaging, spirometry, maximal cardiopulmonary exercise testing, 7-day physical activity and sleep measures and quality of life questionnaires. Blood samples will be collected to assess the microRNA expression profiles, cardiac and inflammatory biomarkers, i.e. cardiac troponin T; N-terminal pro B-type natriuretic peptide; tumour necrosis factor alpha; interleukins 1, 6 and 10; C-reactive protein; d-dimer; and vascular endothelial growth factors. Following baseline assessments, COVID-19 participants will be randomised 1:1 into a 12-week home-based physical activity intervention aiming to increase their daily number of steps by 2000 from baseline. The primary outcome is change in left ventricular global longitudinal strain. Secondary outcomes are arterial stiffness, systolic and diastolic function of the heart, functional capacity, lung function, sleep measures, quality of life and well-being (depression, anxiety, stress and sleep efficiency).DiscussionThe study will provide insights into the cardiovascular implications of COVID-19 and their malleability with a home-based physical activity intervention.Trial registrationClinicalTrials.gov NCT05492552. Registered on 7 April 2022.

VO2max prediction based on submaximal cardiorespiratory relationships and body composition in male runners and cyclists: a population study.

Oxygen uptake (VO2) is one of the most important measures of fitness and critical vital sign. Cardiopulmonary exercise testing (CPET) is a valuable method of assessing fitness in sport and clinical settings. There is a lack of large studies on athletic populations to predict VO2max using somatic or submaximal CPET variables. Thus, this study aimed to: (1) derive prediction models for maximal VO2 (VO2max) based on submaximal exercise variables at anaerobic threshold (AT) or respiratory compensation point (RCP) or only somatic and (2) internally validate provided equations. Four thousand four hundred twenty-four male endurance athletes (EA) underwent maximal symptom-limited CPET on a treadmill (n=3330) or cycle ergometer (n=1094). The cohort was randomly divided between: variables selection (nrunners = 1998; ncyclist = 656), model building (nrunners = 666; ncyclist = 219), and validation (nrunners = 666; ncyclist = 219). Random forest was used to select the most significant variables. Models were derived and internally validated with multiple linear regression. Runners were 36.24±8.45 years; BMI = 23.94 ± 2.43 kg·m-2; VO2max=53.81±6.67 mL·min-1·kg-1. Cyclists were 37.33±9.13 years; BMI = 24.34 ± 2.63 kg·m-2; VO2max=51.74±7.99 mL·min-1·kg-1. VO2 at AT and RCP were the most contributing variables to exercise equations. Body mass and body fat had the highest impact on the somatic equation. Model performance for VO2max based on variables at AT was R2=0.81, at RCP was R2=0.91, at AT and RCP was R2=0.91 and for somatic-only was R2=0.43. Derived prediction models were highly accurate and fairly replicable. Formulae allow for precise estimation of VO2max based on submaximal exercise performance or somatic variables. Presented models are applicable for sport and clinical settling. They are a valuable supplementary method for fitness practitioners to adjust individualised training recommendations. No external funding was received for this work.

The prevalence and predictors of tidal expiratory flow limitation during peak exercise do not differ between genders in healthy adolescents and young adults.

Introduction: Tidal expiratory flow limitation (EFL T ) occurs when the tidal breath reaches its maximal capacity to generate flow despite increased expiratory effort. It has been suggested there are gender differences; females tend to develop EFL T due to lower markers of ventilatory capacity, and the primary determinants of EFL T in males relate to higher oxygen demand. Aim/hypothesis: This study aimed to determine the prevalence and predictors of EFL T during peak exercise in healthy subjects aged 10-24 years. We hypothesised that the prevalence and predictors of EFL T would not differ between males and females. Method: Healthy, physically active subjects (n=122, 69M:53F) with normal spirometry and gas exchange completed a maximal cardiopulmonary exercise test. The presence and degree of EFL T during peak exercise was determined by the vector-based analysis technique described by Welch et al (2021). Student’s T-test compared continuous variables and predictors of EFL T were determined by two-way ANOVA for sex and the presence of EFL T . Results: EFL T was present in 70% of subjects, with no difference in the prevalence between males and females (74 vs. 66%). The degree of EFL T was significantly greater in the males compared to females (40 vs. 30% of tidal volume, p<0.05). Subjects demonstrating EFL T had relatively lower forced expired volume in the first second (FEV 1 ), FEV 1 /forced vital capacity ratio, and mid expiratory flows. During peak exercise, male and female subjects demonstrating EFL T had higher relative peak oxygen consumption, ventilatory equivalents, breathing frequency, and minute ventilation relative to body weight. Conclusion: This study showed no gender difference in the prevalence of EFL T in healthy, physically active subjects. For both genders, lower markers of ventilatory capacity and higher markers of oxygen demand were predictors of EFL T . This research was supported by an award from The Green Lane Research and Education Fund Board. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.