Symptom-limited Exercise Test Research Articles

Changes in left atrial function following two regimens of combined exercise training in patients with ischemic cardiomyopathy: a pilot study.

Left atrial dysfunction has shown to play a prognostic role in patients with ischemic cardiomyopathy (ICM) and is becoming a therapeutic target for pharmacological and non-pharmacological interventions. The effects of exercise training on the atrial function in patients with ICM have been poorly investigated. In the present study, we assessed the effects of a 12-week combined training (CT) program on the left atrial function in patients with ICM. We enlisted a total of 45 clinically stable patients and randomly assigned them to one of the following three groups: 15 to a supervised CT with low-frequency sessions (twice per week) (CTLF); 15 to a supervised CT with high-frequency sessions (thrice per week) (CTHF); and 15 to a control group following contemporary preventive exercise guidelines at home. At baseline and 12 weeks, all patients underwent a symptom-limited exercise test and echocardiography. The training included aerobic continuous exercise and resistance exercise. The analysis of variance (ANOVA) was used to compare within- and inter-group changes. At 12 weeks, the CTLF and CTHF groups showed a similar increase in the duration of the ergometric test compared with the control (ANOVA p < 0.001). The peak atrial longitudinal strain significantly increased in the CTHF group, while it was unchanged in the CTLF and control groups (ANOVA p = 0.003). The peak atrial contraction strain presented a significant improvement in the CTHF group compared with the CTLF and control groups. The left ventricular global longitudinal strain significantly increased in both the CTHF and the CTLF groups compared with the control group (ANOVA p = 0.017). The systolic blood pressure decreased in the CTHF and CTLF groups, while it was unchanged in the control group. There were no side effects causing the discontinuation of the training. We demonstrated that a CT program effectively improved atrial function in patients with ICM in a dose-effect manner. This result can help with programming exercise training in this population.

Neurophysiological Mechanisms of Exertional Dyspnea in Patient’s Post-Pulmonary Embolism: The Effect of Inhaled Nitric Oxide

Following pulmonary embolism (PE), up to a third of patients develop persistent activity-related dyspnea, even in those without chronic thromboembolic pulmonary hypertension (CTEPH). It has been shown that heightened exertional dyspnea in patients post-PE (without CTEPH) is linked to greater inspiratory neural drive (IND) during exercise. The heightened IND, in turn, is secondary to increased physiological dead space (VD/VT) and greater ventilatory requirements for CO2 (VE/VCO2). The reasons for the increased VD/VT and VE/VCO2 are unclear, although pulmonary microvascular dysfunction and the corresponding capillary hypoperfusion is a potential mechanism. Thus, the current study tested the hypothesis that inhaled nitric oxide (iNO), a selective pulmonary vasodilator, would lower exertional IND and dyspnea, and improve exercise endurance in patients post-PE. In turn, the reduced IND and dyspnea would be linked to reductions in VD/VT and VE/VCO2. In this randomized, double-blind, placebo-controlled crossover study, 14 clinically stable patients with chronic activity related dyspnea post-PE (without evidence of PH) completed symptom-limited constant work rate cycle exercise tests while breathing iNO (40 ppm) or placebo (21% O2), on separate days. IND (assessed by diaphragm electromyography), VD/VT and VE/VCO2 (expired and arterialized blood gas), and dyspnea intensity (modified Borg 0-10 scale) were compared throughout exercise. At rest, right-ventricular systolic pressure (RVSP) with placebo or iNO was estimated by echocardiography. At the highest individual standardized exercise time (5.8±2.0 min), iNO decreased VD/VT (0.22±0.09 vs 0.27±0.07, p=0.02), VE/VCO2 (33.0±3.5 vs 34.5±3.8 units, p=0.04), IND (48.8±10.3 vs 57.6±11.8 %, p=0.02) and dyspnea intensity (3.0±1.0 vs 4.0±1.4 Borg units, p&lt;0.01), compared with placebo. Throughout exercise, estimated alveolar ventilation, O2 saturation, O2 pulse and operating lung volumes were unaffected by iNO (all p&gt;0.05). iNO increased exercise endurance time (8.1±3.5 vs 6.5±2.3 min, p&lt;0.001), compared with placebo. iNO reduced resting RVSP by 2.5±2.0 mmHg. iNO decreased exertional IND and dyspnea, and improved exercise endurance in patients with post-PE. The reduced IND, in turn, may be linked to decreased VD/VT and VE/VCO2, reflecting improved ventilation/perfusion. These data provide preliminary evidence of a partially reversible pulmonary vasculopathy, that contributes to dyspnea and exercise limitation in symptomatic patients post-PE. Queen’s University Spear Endowment Grant. This is the full abstract presented at the American Physiology Summit 2024 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.

Exercise limitation in hypertrophic cardiomyopathy: combined stress echocardiography and cardiopulmonary exercise test.

The study aims to investigate exercise-limiting factors in hypertrophic cardiomyopathy (HCM) using combined stress echocardiography and cardiopulmonary exercise test. A symptom-limited ramp bicycle exercise test was performed in the semi-supine position on a tilting dedicated ergometer. Echocardiographic images were obtained concurrently with gas exchange measurements along predefined stages of exercise. Oxygen extraction was calculated using the Fick equation at each activity level. Thirty-six HCM patients (mean age 67±6years, 72% men, 18 obstructive HCM) were compared with age and sex-matched 29 controls. At rest, compared with controls, E/E' ratio (6.26±2.3 vs. 14±2.5, P<0.001) and systolic pulmonary artery pressures (SPAP) (22.6±3.4 vs. 34±6.2mmHg, P=0.023) were increased. Along with the stages of exercise (unloaded; anaerobic threshold; peak), diastolic function worsened (E/e' 8.9±2.6 vs. 13.8±3.6 P=0.011; 9.4±2.3 vs. 18.6±3.3 P=0.001; 8.7±1.9 vs. 21.5±4, P<0.001), SPAP increased (23±2.7 vs. 33±4.4, P=0.013; 26±3.2 vs. 40±2.9, P<0.001; 26±3.5 vs. 45±7mmHg, P<0.001), and oxygen consumption (6.6±1.7 vs. 6.8±1.6, P=0.86; 18.1±2.2 vs. 14.6±1.5, P=0.008; 20.3±3 vs. 15.1±2.1mL/kg/min, P=0.01) was reduced. Oxygen pulse was blunted (6.3±1.8 vs. 6.2±1.9, P=0.79; 10±2.1 vs. 8.8±1.6, P=0.063; 12.2±2 vs. 8.2±2.3mL/beat, P=0.002) due to an insufficient increase in both stroke volume (92.3±17 vs. 77.3±14.5 P=0.021; 101±19.1 vs. 87.3±15.7 P=0.06; 96.5±12.2 vs. 83.6±16.1mL, P=0.034) and oxygen extraction (0.07±0.03 vs. 0.07±0.02, P=0.47; 0.13±0.02 vs. 0.10±0.03, P=0.013; 0.13±0.03 vs. 0.11±0.03, P=0.03). Diastolic dysfunction, elevated SPAP, and the presence of atrial fibrillation were associated with reduced exercise capacity. Both central and peripheral cardiovascular limitations are involved in exercise intolerance in HCM. Diastolic dysfunction seems to be the main driver for this limitation.

Novel wireless laser doppler flowmeter-based investigation of earlobe vascular dynamics in cardiopulmonary exercise testing.

[Purpose] A new wireless laser Doppler blood flowmeter has facilitated easier, more stable measurement of skin perfusion during exercise. However, earlobe blood flow during the cardiopulmonary exercise test remains unascertained. This study aimed to clarify the characteristics of earlobe blood flow during incremental exercise load in healthy individuals. [Participants and Methods] Among 25 healthy males (age 23.6 ± 2.5 years), cycle ergometer-based symptom-limited cardiopulmonary exercise test, after 4 minutes of rest, was conducted with a 4-minute 20W warm-up and a continuous 2W-increase in the work rate every 6 seconds; earlobe blood flow was measured using a wireless laser Doppler blood flowmeter. [Results] Compared with that at rest, earlobe blood flow increased significantly from 50% of exercise peak intensity to a maximum of 1.7 times, but decreased immediately after exercise. The earlobe blood flow %change did not significantly correlate with hemodynamic parameters and its inflection point 36.4% Loadpeak was significantly lower than the anaerobic metabolic threshold 58.1% Loadpeak. [Conclusion] In healthy participants, earlobe blood flow during cardiopulmonary exercise test increased gradually with low-intensity exercise from approximately 1.5 times the resting rate and approached the anaerobic metabolic threshold with a maximum of 1.7 times the resting earlobe blood flow, but decreased quickly after exercise.

Defective exercise-related expiratory muscle recruitment in patients with PHOX2B mutations: A clue to neural determinants of the congenital central hypoventilation syndrome

Introduction and objectivesThe human congenital central hypoventilation syndrome (CCHS) is caused by mutations in the PHOX2B (paired-like homeobox 2B) gene. Genetically engineered PHOX2B rodents exhibit defective development of the brainstem retrotrapezoid nucleus (RTN), a carbon dioxide sensitive structure that critically controls expiratory muscle recruitment. This has been linked to a blunted exercise ventilatory response. Whether this can be extrapolated to human CCHS is unknown and represents the objective of this study. Materials and methodsThirteen adult CCHS patients and 13 healthy participants performed an incremental symptom-limited cycle cardiopulmonary exercise test. Responses were analyzed using guideline approaches (ventilation V'E, tidal volume VT, breathing frequency, oxygen consumption, carbon dioxide production) complemented by a breathing pattern analysis (i.e. expiratory and inspiratory reserve volume, ERV and IRV). ResultsA ventilatory response occurred in both study groups, as follows: V'E and VT increased in CCHS patients until 40 W and then decreased, which was not observed in the healthy participants (p<0.001). In the latter, exercise-related ERV and IRV decreases attested to concomitant expiratory and inspiratory recruitment. In the CCHS patients, inspiratory recruitment occurred but there was no evidence of expiratory recruitment (absence of any ERV decrease, p<0.001). ConclusionsAssuming a similar organization of respiratory rhythmogenesis in humans and rodents, the lack of exercise-related expiratory recruitment observed in our CCHS patients is compatible with a PHOX2B-related defect of a neural structure that would be analogous to the rodents' RTN. Provided corroboration, ERV recruitment could serve as a physiological outcome in studies aiming at correcting breathing control in CCHS.

Does Smartphone Addiction Impair Maximal Exercise Capacity in Young Adults?

Purpose: Smartphone addiction may reduce the time allocated for physical activity participation. However, it is not known if there is a direct association between smartphone addiction and reduced exercise capacity. Our aim was to investigate whether smartphone addiction impairs maximal exercise capacity, as well as analyzing its influence on the perceived benefits of exercise and physical activity habits in young adults.&#x0D; Material and Method: Forty-six volunteers were evaluated by a symptom-limited incremental exercise test. Smartphone addiction of volunteers was evaluated using Smartphone Addiction Scale- Short Form. Physical activity participation and perceived benefits of physical activity participation were evaluated using International Physical Activity Questionnaire- Short Form and Exercise Benefits/Barriers Scale, respectively.&#x0D; Results: Prevalence of smartphone addiction was 65% in young adults. No significant association was detected between smartphone addiction and any of maximal exercise capacity metrics including test duration, maximum workload achieved in watts or maximum heart rate (p&gt;0.05). Smartphone addiction did not correlate to physical activity participation either (p&gt;0.05). Univariate linear regression revealed Exercise Benefits/Barriers Scale score was able to explain 41% of variance in exercise test duration and 37% of variance in maximal workload (p

FEASIBILITY OF AEROBIC FITNESS TESTING IN AMNESTIC MILD COGNITIVE IMPAIRMENT FROM THE ACT TRIAL

Abstract Aerobic fitness has been postulated as a physiological mechanism of action for aerobic exercise to modify Alzheimer’s disease, but it has not been adequately studied in older adults with (MCI). The purpose of this study is to evaluate the feasibility of a gold-standard, laboratory-based, symptom-limited cycle-ergometer exercise testing (GXT) in older adults with amnestic mild cognitive impairment (aMCI) to assess peak oxygen consumption (VO2max [ml/kg/min]) using baseline data from the ACT Trial. The test was categorized as a submax, near-max, and max test based on if 0, 1, and ≥2 of the American College of Sports Medicine criteria was met: &amp;gt;90% of age-predicted maximum heart rate, plateau in VO2Peak, respiratory exchange ratio &amp;gt;1.10, and rating of perceived exertion &amp;gt;17. VO2max was predicted as 3.5*maximal metabolic equivalents (METs). Among 146 enrolled participants (73.8±5.7 years old with 16.9±2.9 years of education, 51.4% men, and 91.8% Caucasian), 145 completed GXTs. Sixteen GXTs (11.0%) were submax (VO2Peak 13.5±4.4), 53 (36.6%) were near-max (VO2Peak 16.5±4.1), and 76 (52.4%) were max (VO2Peak 18.4±5.1). Predicted VO2max were 21.6±6.8, 28.7±26.3, and 30.0±20.5 from submax, near-max, and max tests, respectively. Among max GXTs, VO2max was 19.5±4.9 in men (n=37) and 17.4±5.1 in women (n=39). In conclusion, GXTs was feasible for ~52% of the participants. METs-based prediction overly inflates VO2max estimates, in comparison to VO2max obtained from max GXTs. VO2max levels are substantially lower in older adults with aMCI than peers (23.1±6.3 in men and 21.1±3.4 in women), suggesting aerobic exercise as an important intervention for this population.

Cardiorespiratory Fitness in Patients With Early-Stage Breast Cancer and Radiation Therapy-Related Fatigue: A Prospective Pilot Study

Purpose/ObjectivesFatigue is among the most common but one of the most poorly understood radiotherapy-associated toxicities. This prospective study sought to investigate whether cardiorespiratory fitness, an integrative measure of whole-body cardiopulmonary function, is associated with patient-reported fatigue among women with early-stage breast cancer undergoing radiotherapy. Materials/MethodsPatients with stage Tis-T2N0M0 breast cancer and an ECOG performance status of 0-1 who were undergoing breast radiotherapy performed a symptom-limited cardiopulmonary exercise test (CPET) on a motorized treadmill to assess cardiorespiratory fitness (VO2peak). Fatigue was assessed by the FACIT Fatigue Scale. Both assessments were performed during or immediately after radiotherapy completion. All patients were treated with an opposed tangent technique to a dose of 4240 cGy in 16 fractions with or without a lumpectomy bed boost. Patients receiving cytotoxic chemotherapy were excluded. Pearson's correlation coefficients and univariate linear regression were used to assess associations between VO2peak, fatigue, and patient characteristics. ResultsTwenty-eight patients (median age 52 years, range 31-71) completed both CPET and FACIT assessments. Median VO2peak was 25.1 mL O2.kg−1.min−1 (range 16.7-41.7). The majority of subjects (78.6%) displayed a VO2peak less than their age-predicted VO2peak. Both age and BMI were significantly associated with VO2peak levels. Median fatigue score was 41.5 (range 10-52), with lower values indicating more fatigue. VO2peak was not associated with FACIT score (p=0.20). ConclusionsOverall, VO2peak was not a significant predictor of radiotherapy-related fatigue. Most breast cancer patients had marked impairments in cardiorespiratory fitness as determined by VO2peak. Larger prospective studies are needed to further investigate this novel finding, and to evaluate the effects of interventions aimed at improving cardiorespiratory fitness and their ability to potentially prevent fatigue.

Medical Rehabilitation of Patients with Post-COVID-19 Syndrome-A Comparison of Aerobic Interval and Continuous Training.

Post-COVID-19 syndrome (PCS) is a multisystemic disorder marked by impaired physical performance as one lead symptom. Since it has been suggested that endurance training as part of medical rehabilitation may be effective in improving physical performance capacity in PCS, this study aimed to compare different modes of aerobic endurance training. A total of 110 PCS patients (49.3 ± 11.8 years; 38% women; time after infection = 260.2 ± 127.5 days) underwent detailed clinical screening including symptom-limited cardiopulmonary exercise testing at admission and after 4-6 weeks of inpatient medical rehabilitation. Questionnaires were used to assess disease perception. Patients performed controlled isocaloric cycle ergometer training (3-5 sessions/week; 18 min) as either continuous training (CT) at 50% of maximal workload or as interval training (IT; load = 60%, relief = 30%). Outcomes of PCS patients were compared to coronary artery disease patients (CAD; n = 96) to evaluate overall training effectiveness. Training participation was comparable between the groups, with no indication of training-specific exercise-induced fatigue. Overall, PCS patients improved significantly by a mean of 6.8 ± 12.1% for W at VT1; 3.1 ± 10.0% for VO2 at VT1; 5.5 ± 14.7% for O2 pulse at VT1; 7.5 ± 15.0% for W at VO2peak; 2.7 ± 11.0% for VO2peak and 4.6 ± 12.4% for O2 pulse at VO2peak (all p < 0.05) with no significant differences between groups (p > 0.05). Both groups showed reduced levels of fatigue, anxiety, and depression as well as improved quality of life and wellbeing (all p < 0.05). Compared to guideline-based cardiac rehabilitation, PCS patients showed a similar improvement in workload and oxygen uptake compared to CAD patients. PCS patients benefit from aerobic endurance training performed as moderate continuous or interval training as part of a medical rehabilitation program in terms of improved physical exercise capacity and disease perception. The results for PCS patients are comparable to the guideline-based rehabilitation of CAD patients.

Study on the correlation between type 2 diabetes mellitus combined with non-alcoholic steatohepatitis and aerobic exercise performance

Objective: To study the correlation between patients with type 2 diabetes mellitus combined with nonalcoholic steatohepatitis in order to provide theoretical support for the treatment of NAFLD through aerobic exercise performance. Methods: 253 cases with T2DM combined with NAFLD were selected. 93 cases consented to undergo a liver biopsy. Among them, 74 cases with liver biopsy successfully passed the symptom-limited cardiopulmonary exercise test (CPET) and respiratory quotient (RQ)≥1.05. Patients were divided into two groups according to the NAFLD activity score (NAS) of the pathological biopsy: the non-NASH group (NAS < 4) and the NASH group (NAS≥4). The differences in general clinical and biochemical indicators and exercise parameters were compared between the two groups. The relevant factors that affect aerobic exercise performance in NAFLD patients were explored by correlation and regression analysis. Results: The peak oxygen uptake [VO2 @ peak, (17.82 ± 5.61) ml·kg(-1)·min(-1) and (23.14 ± 5.86) ml·kg(-1)·min(-1)] and anaerobic threshold [VO2 @ AT, (11.47 ± 3.12) ml·kg(-1)·min(-1) and (13.81 ± 3.53) ml·kg(-1)·min(-1)] were lower in the NASH group than those in the non-NASH group in T2DM patients, with P < 0.01, indicating a significant decrease in aerobic exercise performance in NASH patients compared to non-NASH patients. Correlation analysis showed that patients with T2DM combined with NAFLD VO2@peak was positively correlated with RQ, carbohydrate oxidation rate (%CHO), daily carbohydrate energy supply (CHO Kcal/d), high-density lipoprotein cholesterol (HDL-C), and maximal voluntary ventilation (MVV) (r 0.360, 0.334, 0.341, 0.255, 0.294, P < 0.05 or P < 0.01, respectively) and negatively correlated with NAS score, fat attenuation, liver stiffness, fat oxidation rate (%FAT), daily fat energy supply (FAT Kcal/d), aspartate aminotransferase (AST), alanine aminotransferase (ALT), body mass, and body mass index (BMI) (r -0.558, -0.411, -0.437, -0.340, -0.270, -0.288, -0.331, -0.295, -0.469, P < 0.05 or P < 0.01, respectively). VO2@AT were positively correlated with RQ, %CHO, total cholesterol (TC), and HDL-C (r 0.351, 0.247, 0.303, 0.380, P < 0.05 or P < 0.01, respectively), while it was negatively correlated with NAS score, fat attenuation, liver stiffness, %FAT, FAT (Kcal/d), ferritin (Fer), ALT, AST, body weight, and BMI (r -0.330, -0.384, -0.428, -0.270, -0.318, 0.320, -0.404, -0.416, -0.389, -0.520, P < 0.05 or P < 0.01, respectively). Stepwise multiple regression analyses revealed that BMI, RQ, and NAS scores were independent correlated factors of aerobic exercise performance. Conclusion: Hepatic inflammation and fibrosis affect the aerobic exercise performance of patients with T2DM combined with NAFLD.

Sympathovagal Balance and Body Shape Index in Elite and Amateur Athletes: The Relationship Unraveled.

Background Heart rate variability (HRV) is one piece among a complex network of adaptations existent in athletes that help them gain a better understanding of their own physiology. Sympathovagal balance is one of the spectral components of HRV analysis and is used to assess the frequently changing oscillations of a healthy heart, which can help in gauging the response of cardiac function towards physiological stress during exercise. This index is extensively used in appraising cardiac autonomic modulation. An evaluation of body composition in athletes has become a critical consideration when tracking HRV, as it helps practitioners understand the role of the autonomic nervous system (ANS) in obesity. The body shape index (BSI), which is based on waist circumference (WC), is an anthropometric parameter with decent predictive ability when measuring centripetal obesity. In this regard, the current study is an attempt to unravel the relationship between BSI and sympathovagal balance during exercise performed on two different instruments (treadmill and ergometer) by elite and amateur athletes. Methods It was an observational case-control study that included 30 elite and 120 amateur athletes. Symptom-limited exercise testing was performed by athletes on a motorized treadmill and ergometer in the sports physiology laboratory of a rural medical college in central India. Different anthropometric parameters like BSI and body surface area (BSA) were also recorded. Short-term HRV extracted fromelectrocardiogram (ECG) recordings was obtained using the Power Lab system and HRV analysis by LabChart software. Results The sympathovagal ratio, i.e., ratio of low frequency (LF) to high frequency (HF) in elite and amateur male populations showed a higher value than that in females, indicating a dominant sympathetic response in the males. There was a significant (p=0.042) positive correlation (r=0.24) between BSI and LF/HF Ratio in amateur females during treadmill exercise, whereas a significant (p=0.049) negative correlation (r=-0.27) was obtained in amateur males during ergometer exercise. Hence, increased weight and BSI were found to be associated with high sympathetic dominance, indicating a sympathovagal imbalance. Conclusion We attempted to explore the interaction between BSI and LF/HF during exercise performed on two different instruments (treadmill and ergometer) by elite and amateur athletes, which can help in testing the response of cardiac function to stress experienced during exercise. The study's uniqueness stems from discovering the relationship between BSI and HRV and how this relationship impacts sports performance. BSI measurement in athletes, both elite and amateur, allows for the assessment and forecasting of potential autonomic activity under exercise-induced stress by linking HRV with BSI.

An experimental study to diagnose coronary artery disease using five treadmill scores

Objectives: Exercise is the first step of a cardiovascular stress test, including electrocardiography (ECG) and blood pressure monitoring. Typically, a treadmill or bicycle is used to carry out the exercise for this stress test. Computer-derived criteria and a scoring system have been proposed and tested in hopes of improving the diagnostic accuracy of the exercise ECG for diagnosing coronary artery disease (CAD). Many treadmill scores have not been compared with one another in the same population, so questions remain concerning their diagnostic accuracy. The study aimed to correlate the diagnostic accuracy of ST segment response with various treadmill scores. Material and Methods: A total of 100 consecutive patients with suspected CAD referred for exercise testing at ACS Medical College and Hospital, Chennai, Tamil Nadu, between December 2021 and June 2022 were included in the study. The Institutional Review Board approved the study protocol at our institution, and all patients provided written informed consent. A treadmill test was conducted using commercially available equipment. All patients were subjected to symptom-limited exercise testing following the standard Bruce and modified Bruce protocols. A series of five scores were calculated using data collected from the patients to calculate the probability of CAD occurrence. Results: The study included 100 patients with an average age of 48.4 ± 1 years. Obesity (41%), hypertension (80%), diabetes (86%), current smokers (62%), family history of CAD (46%), and hypercholesterolemia (46%) were all observed in the study. The receiver operator characteristic (ROC) plot’s area under the curve (AUC) (standard error) for the Detrano score was 0.46 ± 0.59. This was significantly lower than the AUC of each treadmill score. The AUC of the ROC plots of the Duke treadmill score (DTS), veterans affairs (VA), and consensus scores were 0.47 ± 0.58, 0.63 ± 0.56, and 0.61 ± 0.57, respectively. Conclusion: The Morise score remains helpful in our study population for detecting CAD and determining risk strata. DTS and Detrano had comparable accuracy when calculated from intermediate and high probability scores and ST responses (44% and 43%, respectively). VA and consensus had lower accuracy than others (37% and 29%, respectively).

Extracellular volume is an independent predictor of peak cardiac power in asymptomatic patients with moderate-to-severe aortic stenosis

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): The PRIMID study was funded by an NIHR fellowship (Post-Doctoral Fellowship supported by the National Institute for Health Research (NIHR-PDF 2011–04–51 Gerald P McCann.) Background Cardiac power (CP) describes the cardiac work done to maintain arterial pressure in the vasculature and peak CP is the ceiling of pumping performance the heart can achieve. Mean pressure gradient adjusted CP (MPG-CP) gives a more accurate representation of afterload in patients with aortic stenosis (AS) but its association with left-ventricular remodelling parameters is unknown. Purpose To establish the determinants of peak MPG-CP in asymptomatic patients with AS. Methods In this prospective, multi-centre observational study, asymptomatic patients with moderate to severe AS underwent echocardiography, cardiovascular magnetic resonance (CMR) imaging and cardiopulmonary exercise testing. Peak MPG-CP was calculated at peak exercise during an incremental symptom-limited exercise test on semi-supine ergometer, using the formula shown (Figure-1). Clinical and imaging univariable and multivariable associations of peak MPG-CP were assessed by linear regression. Results Peak MPG-CP was measured in 86 patients (mean age 66±12 years, 77% male, mean aortic valve area (AVA) 1.08±0.33 cm^2). On univariable analysis, peak MPG-CP was directly correlated with echocardiogram-measured AVA, peak pressure gradient, max velocity, and CMR-measured myocardial perfusion reserve (MPR), LV mass index (LVMI) and LV end-diastolic volume index (LVEDVI), and inversely correlated with extracellular volume (ECV) and NT-proBNP (Table-1). ECV was the only variable independently associated with peak MPG-CP regardless of which measure of AS severity was inputted in the multivariable model. Conclusions ECV, a marker of diffuse interstitial fibrosis, is an independent predictor of peak MPG-CP in asymptomatic patients with moderate-severe AS. Given ECV's role as a prognosticator, CP parameters may be important markers of subclinical disease and serve as surrogates for fibrotic burden and risk-stratification tools in asymptomatic AS.

Thirteen-Year Associations of Occupational and Leisure-Time Physical Activity with Cardiorespiratory Fitness in CARDIA.

Differential effects on fitness are hypothesized to contribute to the opposing health effects of leisure-time physical activity (LTPA) and occupational physical activity (OPA). As such, this study examined cross-sectional and longitudinal associations of fitness with LTPA and OPA. This study examined fitness associations with LTPA and OPA across 13 yr in the Coronary Artery Risk Development in Young Adults study (years 7 (baseline), 10, 15, and 20 (follow-up) examinations). Fitness was measured at baseline and follow-up via symptom-limited maximal graded exercise test (GXT) duration (in seconds), whereas LTPA and OPA were self-reported during each examination. Baseline and follow-up cross-sectional associations of LTPA (low, medium, high) and OPA (0, 1-6, and ≥6 months with OPA) with fitness were examined using linear regression. Longitudinal linear regression examined associations between 13-yr LTPA (low, medium, or high) and OPA (no, decreasing, or increasing) trajectories with fitness at follow-up, adjusted for baseline values. All models adjusted for center, sex, race, age, education, smoking history, alcohol intake, resting blood pressure, diabetes status, and body mass index. Stratified analyses examined associations by sex (female/male), race (Black/White), and LTPA groups. Compared with low, medium, and high LTPA were positively associated with fitness in all analyses ( P < 0.001). Reporting 1-6 or ≥6 months with OPA was negatively associated with fitness in cross-sectional follow-up models ( β = -15.6 and -15.4, respectively; P ≤ 0.01). Longitudinally, those with increasing OPA had lower follow-up fitness compared with no OPA ( β = -16.41, P < 0.01). Negative associations of OPA with fitness were not meaningfully different across sex and race groups. Significant LTPA-OPA interactions were observed ( P < 001). Physical activity research and public health promotion should consider domain-specific associations on cardiovascular health.

Effect of Coronary Sinus Reducer Implantation on Aerobic Exercise Capacity in Refractory Angina Patients—A CROSSROAD Study

Coronary sinus reducer (CSR) implantation is a new treatment option for patients with refractory angina pectoris. However, there is no evidence from a randomized trial that would show an improvement in exercise capacity after this treatment. The aim of this study was to evaluate the influence of CSR treatment on maximal oxygen consumption and compare it to a sham procedure. Twenty-five patients with refractory angina pectoris (Canadian Cardiovascular Society (CCS) class II–IV) were randomized to a CSR implantation (n = 13) or a sham procedure (n = 12). At baseline and after 6 months of follow-up, the patients underwent symptom-limited cardiopulmonary exercise testing with an adjusted ramp protocol and assessment of angina pectoris using the CCS scale and Seattle angina pectoris questionnaire (SAQ). In the CSR group, maximal oxygen consumption increased from 15.56 ± 4.05 to 18.4 ± 5.2 mL/kg/min (p = 0.03) but did not change in the sham group (p = 0.53); p for intergroup comparison was 0.03. In contrast, there was no difference in the improvement of the CCS class or SAQ domains. To conclude, in patients with refractory angina and optimized medical therapy, CSR implantation may improve oxygen consumption beyond that of optimal medical therapy.

Effect of hybrid cardiac rehabilitation using a smart device: a randomized controlled trial

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Korea National Institute of Health. Background Although cardiac rehabilitation (CR) has been proven to be effective in secondary prevention for patients with cardiovascular diseases, the actual participation in CR is still unsatisfactory. Because home-based CR provides better access to patients and is as effective as center-based CR, it is considered a promising alternative that can overcome various barriers impeding CR implementation. However, home-based CR has not garnered enough attention due to a lack of proper communication, concerns about unexpected adverse events caused by non-monitored exercises, and the absence of supporting insurance services. Purpose We utilized a smart ring with a photoplethysmography to monitor heart rate. Recorded data were stored on a website where the researchers could remotely access and check the uploaded measurements. This study aims to identify the clinical effects of hybrid CR by weekly telephone counseling based on the patients' actual physical activities obtained from the device. Methods Cardiovascular disease patients were educated on concrete methods of home-based CR, including the type, intensity, and time of exercise as well as precautions. They were also instructed to wear the device during exercise. The patients were randomly enrolled into two groups: intervention and observation groups. The patients of the intervention group were given weekly telephone counseling and encouraged to maintain optimal physical activities. In the observational group, only exercise data were recorded without additional interventions. Before and after three months of training, the results of the symptom-limited cardiopulmonary exercise test between the two groups were compared. Results A total of sixty-four patients were enrolled (thirty-two in each group). The subjects were 59.8 ± 9.0 years old and fifty-three (82.8%) were male. There were no significant differences in diagnosis and results of baseline symptom-limited cardiopulmonary exercise test between the two groups (Table 1). After three months of training, peak oxygen consumption was significantly improved in both groups. However, the improvement was greater in the intervention group compared to the observation group (Table 2). Conclusion Home-based CR using a smart device was effective in improving oxygen consumption. For greater effectiveness, proper monitoring and timely counseling by medical experts are likely to be necessary.

Impact of a cardio-oncology rehabilitation framework among high cardiovascular risk cancer survivors: results from the CORE trial

Abstract Funding Acknowledgements Type of funding sources: None. Background Cancer survivors are challenging patients, as they often present increased cardiovascular (CV) risk. In this background, cardio-oncology rehabilitation frameworks for specific cancer patients have been proposed. However, optimal program designs, as well as their overall safety and efficacy in different subsets of patients, are not fully ascertained. Purpose To assess the impact of a cardio-oncology rehabilitation based framework for cancer patients at increased CV risk, compared to a community-based exercise training (CBET), on cardiorespiratory fitness (CRF) and cardiovascular risk factor (CVRF) control. Methods The CORE study was a single-center, prospective, randomized controlled trial enrolling adult cancer survivors exposed to cardiotoxic cancer treatment (anthracycline, radiotherapy on thoracic wall, anti-human epidermal growth factor receptor-type 2 drugs) and/or with previous CV disease. Participants were randomized to an 8-week center-based CR program (CBCR) or CBET, twice a week. Primary endpoint was CRF (assessed by the VO2peak, derived from a symptom-limited cardiopulmonary exercise test, performed on a treadmill); secondary endpoints were physical activity [International Physical Activity Questionnaire (IPAQ)], psychosocial parameters [Hospital Anxiety and Depression Scale (HADS)], blood pressure, body composition, lipid profile and health literacy [Newest Vital Sign (NVS) questionnaire]. Results 80 patients were included (mean age 54.5±14,12, 61 women; 66% breast cancer, 27.5% lymphoma); 75 patients completed the intervention (CBCR N= 38; CBET N=37). There was a significant improvement in the CBCR compared to the CBET group in VO2peak (∆ +2.1±2.8 vs +0.8±2.5 mL.kg-1.min-1, p=0.033) and in the following outcomes: resting systolic blood pressure (p&amp;lt;0.0001); body mass index (p&amp;lt;0.0001), lean and fat body mass (p&amp;lt;0.0001), waist circumference (p&amp;lt;0.0001); total cholesterol (p =0.001), triglycerides (p =0.008) and LDL cholesterol (p =0.003); HADS Anxiety score (p =0.003) and Depression score (p =0.009), weekly physical activity levels (p&amp;lt;0.0001) and health literacy scores (p&amp;lt;0.0001). No major CV events were reported. Conclusion The CORE trial demonstrates superior results of a CBCR regarding CRF and CVRF control. Given the higher cardiovascular risk in several groups of cancer patients, our data provides novel insights into optimized preventive strategies in this complex patient population.

Single-cell sequencing of immune cells after marathon and symptom-limited cardiopulmonary exercise.

Vigorous-intensity leisure-time physical activity, such as marathon, has become increasingly popular, but its effect on immune functions and health is poorly understood. Here, we performed scRNA-seq analysis of peripheral blood mononuclear cells (PBMCs) after a bout of symptom-limited cardiopulmonary exercise (CPX) test or marathon. Time-series single-cell analysis revealed the detailed series of landscapes of immune cells in response to short and long vigorous-intensity activities. Reduction of effective Tcells was observed with the cell migration and motility pathways enriched in circulation following marathon. Baseline values of PBMCs abundance were reached around 1h after CPX and 24h following marathon, but longer time was required for expression recovery of cytotoxicity genes. The ratio of effector/naive Tcells was found to change uniformly among the participants and could serve as a better indicator for exercise intensity than the CD4+/CD8+ Tcell ratio. Moreover, we identified time-dependent monocyte state transitions after marathon.

Correlation between Heart rate recovery and Left Atrial phasic functions evaluated by 2D speckle-tracking Echocardiography after Acute Myocardial infarction

BackgroundHeart rate recovery (HRR) in the exercise test is the index of cardiac autonomic system function and sympathovagal balance impaired in patients with myocardial infarction (MI). An instance is left atrial (LA) phasic function, which is impaired in such patients. In this study, we investigated the role of HRR in predicting LA phasic functions in patients with MI.MethodsThe present study recruited 144 consecutive patients with ST-elevation MI. A symptom-limited exercise test was performed about 5 weeks after MI, with echocardiography conducted just before the exercise test. The patients were divided into abnormal and normal HRR at 60 s (HRR60) and again into abnormal and normal HRR at 120 s (HRR120) after the exercise test. LA phasic functions, evaluated by 2D speckle-tracking echocardiography, were compared between the 2 groups.ResultsPatients with abnormal HRR120 had lower LA strain values and strain rates during the reservoir, conduit, and contraction phases, while those with abnormal HRR60 had lower LA strain values and strain rates during the reservoir and conduit phases. The differences were lost after adjustments for possible confounders, except for LA strain and strain rate during the conduit phase, in patients with abnormal HRR120.ConclusionsAbnormal HRR120 in the exercise test can independently predict decreased LA conduit function in patients with ST-elevation MI.

Maximal Exercise Improves the Levels of Endothelial Progenitor Cells in Heart Failure Patients.

The impact of exercise on the levels of endothelial progenitor cells (EPCs), a marker of endothelial repair and angiogenesis, and circulating endothelial cells (CECs), an indicator of endothelial damage, in heart failure patients is largely unknown. This study aims to evaluate the effects of a single exercise bout on the circulating levels of EPCs and CECs in heart failure patients. Thirteen patients with heart failure underwent a symptom-limited maximal cardiopulmonary exercise test to assess exercise capacity. Before and after exercise testing, blood samples were collected to quantify EPCs and CECs by flow cytometry. The circulating levels of both cells were also compared to the resting levels of 13 volunteers (age-matched group). The maximal exercise bout increased the levels of EPCs by 0.5% [95% Confidence Interval, 0.07 to 0.93%], from 4.2 × 10-3 ± 1.5 × 10-3% to 4.7 × 10-3 ± 1.8 × 10-3% (p = 0.02). No changes were observed in the levels of CECs. At baseline, HF patients presented reduced levels of EPCs compared to the age-matched group (p = 0.03), but the exercise bout enhanced circulating EPCs to a level comparable to the age-matched group (4.7 × 10-3 ± 1.8 × 10-3% vs. 5.4 × 10-3 ± 1.7 × 10-3%, respectively, p = 0.14). An acute bout of exercise improves the potential of endothelial repair and angiogenesis capacity by increasing the circulating levels of EPCs in patients with heart failure.