Multi-Ethnic Study of Atherosclerosis Early Heart Failure Study: Rationale, Design, and Baseline Characteristics.

BACKGROUND: Current prevalence estimates of heart failure (HF) are primarily based on self-report or HF hospitalizations. There is an unmet need to define the prevalence and pathogenesis of early symptomatic HF, which may be undiagnosed and precedes HF hospitalization. METHODS: The MESA (Multi-Ethnic Study of Atherosclerosis) Early HF study was conducted during MESA exam 6 to determine the prevalence of early HF and investigate the transition from risk factors to early HF in a diverse population-based cohort of older adults. Between 2016 and 2018, 3285 MESA participants from 6 field centers underwent comprehensive speckle-tracking echocardiography with passive leg raise maneuver, Kansas City Cardiomyopathy Questionnaire, 6-minute walk test, arterial stiffness assessment, and proteomics (including NT-proBNP [N-terminal pro-B-type natriuretic peptide]). RESULTS: Median age was 73 (25th-75th percentile 67-81) years, 53.2% were female, 25.6% were Black, 12.8% were Chinese, and 40.0% were White. The prevalence of HF risk factors was high: hypertension, 61.9%; former or current smoking, 53.7%; obesity 34.8%; diabetes; 24.7%; and chronic kidney disease; 22%. Overt cardiovascular disease, which ranged from 2.1% (HF) to 13.6% (atrial fibrillation), was less common. Of the 3285 participants, 96% underwent proteomics, 94% Kansas City Cardiomyopathy Questionnaire, 93% speckle-tracking echocardiography with passive leg raise, 82% arterial stiffness exam, and 77% 6-minute walk test. Feasibility of resting speckle-tracking echocardiography (87%-99% across cardiac chambers) and passive leg raise Doppler/speckle-tracking echocardiography (>84%) measurements was high. A total of 120 unique echocardiographic indices were measured. CONCLUSIONS: The MESA Early HF study is a key resource for cardiovascular researchers who are interested in improving the epidemiological and phenotypic characterization of early HF. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00005487.

2023 update: The importance of cardiorespiratory fitness in the United States.

The American Heart Association issued a Policy Statement in 2013 that characterized the importance of cardiorespiratory fitness (CRF) as an essential marker of health outcomes and specifically the need for increased assessment of CRF. This statement summarized the evidence demonstrating that CRF is "one of the most important correlates of overall health status and a potent predictor of an individual's future risk of cardiovascular disease." Subsequently, this Policy Statement led to the development of a National Registry for CRF (Fitness Registry and the Importance of Exercise: A National Data Base [FRIEND]) which established normative reference values for CRF for adults in the United States (US). This review provides an overview of the progress made in the past decade to further our understanding of the importance of CRF, specifically related to prevention and for clinical populations. Additionally, this review overviews the evolvement and additional uses of FRIEND and summarizes a hierarchy of assessment methods for CRF. In summary, continued efforts are needed to expand the representation of data from across the US, and to include data from pediatric populations, to further develop the CRF Reference Standards for the US as well as further develop Global CRF Reference Standards.

A single-center survey on physical activity barriers, behaviors and preferences in adults with epilepsy.

BACKGROUND: Improved understanding of physical activity barriersand preferences in people with epilepsyis needed to successfully design and perform larger, more robust effectivenesstrials. METHODS: Adult patients at a single tertiary epilepsy center between January and April 2020 were surveyed. The survey included a validated physical activity questionnaire (Physical Activity Scale for the Elderly) plus 15 items aimed to address 1) perceptions and beliefs regarding physical activity, 2) barriers to routine physical activity, and 3) willingness and ability to participate in a physical activity intervention and 4) current physical abilities, activities, and preferences. RESULTS: 95 participants with epilepsy (age 42 ± 16.2, 59 % female) completed the survey. Sixty-five participants (68.4 %) reported that they believe that physical activity could improve their seizure frequency. However, 40 % of those surveyed said their neurologist had never talked to them about physical activity. The most commonly reported barriers to physical activity were lack of time (24.7 %) and fear of having a seizure (19.7 %), while barriers to intervention participation included being unable to come to in-person sessions (53 % of those willing to participate),living far away (39.3 %), time constraints (28.6 %), and lack of transportation (21.4 %). CONCLUSION: Future physical activity studies in people with epilepsy should focus on using tailored interventions that accommodate their unique beliefs and barriers.

Physical Activity During Breast Cancer Therapy Associates With Preserved Exercise Capacity and Cardiac Function (WF97415).

Background: Cancer treatment increases cardiovascular disease risk, but physical activity (PA) may prevent cardiovascular disease. Objectives: This study examined whether greater PA was associated with better submaximal exercise capacity and cardiac function during cancer therapy. Methods: Participants included 223 women with stage I to III breast cancer (BC) before and 3 months after undergoing treatment and 126 control participants. Leisure-time PA (LTPA) was reported using the Godin-Shephard LTPA questionnaire. Cardiac function was assessed by cardiac magnetic resonance. Submaximal exercise capacity was determined by 6-minute walk distance. Results: BC participants reported similar baseline LTPA scores (24.7; 95% CI: 21.7-28.0) as control participants (29.4; 95% CI: 25.0-34.2). The BC group declined to 16.9 (95% CI: 14.4-19.6) at 3 months relative to 30.8 (95% CI: 26.2-35.8) in control participants. Among BC participants, more LTPA was related to better exercise capacity (ß ± SE: 7.1 ± 1.6; 95% CI: 4.0-10.1) and left ventricular (LV) circumferential strain (-0.16 ± 0.07; 95% CI: -0.29 to -0.02). Increased LTPA over the 3 months was associated with decreased likelihood of treatment-induced cardiac dysfunction according to LV circumferential strain classifications (OR: 0.98; 95% CI: 0.97-0.998). BC participants reporting insufficient LTPA according to PA guidelines exhibited deteriorations in exercise capacity (adjusted mean difference ± SE: -29 ± 10 m; P = 0.029), LV end-systolic volume (5.8 ± 1.3 mL; P < 0.001), LV ejection fraction (-3.2% ± 0.8%; P = 0.002), and LV circumferential strain (2.5% ± 0.5%; P < 0.001), but BC participants meeting LTPA guidelines did not exhibit these adverse changes. Conclusions: PA declined during BC therapy; however, PA participation was associated with attenuated declines in exercise capacity and cardiac function that are often observed in this population. (Understanding and Predicting Breast Cancer Events After Treatment [WF97415 UPBEAT]; NCT02791581).

Skeletal Muscle Mitochondrial Respiration and Exercise Intolerance in Patients With Heart Failure With Preserved Ejection Fraction.

Importance: The pathophysiology of exercise intolerance in patients with heart failure with preserved ejection fraction (HFpEF) remains incompletely understood. Multiple lines of evidence suggest that abnormal skeletal muscle metabolism is a key contributor, but the mechanisms underlying metabolic dysfunction remain unresolved. Objective: To evaluate the associations of skeletal muscle mitochondrial function using respirometric analysis of biopsied muscle fiber bundles from patients with HFpEF with exercise performance. Design, Setting, and Participants: In this cross-sectional study, muscle fiber bundles prepared from fresh vastus lateralis biopsies were analyzed by high-resolution respirometry to provide detailed analyses of mitochondrial oxidative phosphorylation, including maximal capacity and the individual contributions of complex I-linked and complex II-linked respiration. These bioenergetic data were compared between patients with stable chronic HFpEF older than 60 years and age-matched healthy control (HC) participants and analyzed for intergroup differences and associations with exercise performance. All participants were treated at a university referral center, were clinically stable, and were not undergoing regular exercise or diet programs. Data were collected from March 2016 to December 2017, and data were analyzed from November 2020 to May 2021. Main Outcomes and Measures: Skeletal muscle mitochondrial function, including maximal capacity and respiration linked to complex I and complex II. Exercise performance was assessed by peak exercise oxygen consumption, 6-minute walk distance, and the Short Physical Performance Battery. Results: Of 72 included patients, 50 (69%) were women, and the mean (SD) age was 69.6 (6.1) years. Skeletal muscle mitochondrial function measures were all markedly lower in skeletal muscle fibers obtained from patients with HFpEF compared with HCs, even when adjusting for age, sex, and body mass index. Maximal capacity was strongly and significantly correlated with peak exercise oxygen consumption (R = 0.69; P < .001), 6-minute walk distance (R = 0.70; P < .001), and Short Physical Performance Battery score (R = 0.46; P < .001). Conclusions and Relevance: In this study, patients with HFpEF had marked abnormalities in skeletal muscle mitochondrial function. Severely reduced maximal capacity and complex I-linked and complex II-linked respiration were associated with exercise intolerance and represent promising therapeutic targets.

A Randomized, Controlled Trial of Resistance Training Added to Caloric Restriction Plus Aerobic Exercise Training in Obese Heart Failure With Preserved Ejection Fraction.

BACKGROUND: We have shown that combined caloric restriction (CR) and aerobic exercise training (AT) improve peak exercise O2 consumption (VO2peak), and quality-of-life in older patients with obese heart failure with preserved ejection fraction. However, ≈35% of weight lost during CR+AT was skeletal muscle mass. We examined whether addition of resistance training (RT) to CR+AT would reduce skeletal muscle loss and further improve outcomes. METHODS: This study is a randomized, controlled, single-blind, 20-week trial of RT+CR+AT versus CR+AT in 88 patients with chronic heart failure with preserved ejection fraction and body mass index (BMI) ≥28 kg/m2. Outcomes at 20 weeks included the primary outcome (VO2peak); MRI and dual X-ray absorptiometry; leg muscle strength and quality (leg strength ÷ leg skeletal muscle area); and Kansas City Cardiomyopathy Questionnaire. RESULTS: Seventy-seven participants completed the trial. RT+CR+AT and CR+AT produced nonsignificant differences in weight loss: mean (95% CI): -8 (-9, -7) versus -9 (-11, -8; P=0.21). RT+CR+AT and CR+AT had non-significantly differences in the reduction of body fat [-6.5 (-7.2, -5.8) versus -7.4 (-8.1, -6.7) kg] and skeletal muscle [-2.1 (-2.7, -1.5) versus -2.1 (-2.7, -1.4) kg] (P=0.20 and 0.23, respectively). RT+CR+AT produced significantly greater increases in leg muscle strength [4.9 (0.7, 9.0) versus -1.1 (-5.5, 3.2) Nm, P=0.05] and leg muscle quality [0.07 (0.03, 0.11) versus 0.02 (-0.02, 0.06) Nm/cm2, P=0.04]. Both RT+CR+AT and CR+AT produced significant improvements in VO2peak [108 (958, 157) versus 80 (30, 130) mL/min; P=0.001 and 0.002, respectively], and Kansas City Cardiomyopathy Questionnaire score [17 (12, 22) versus 23 (17, 28); P=0.001 for both], with no significant between-group differences. Both RT+CR+AT and CR+AT significantly reduced LV mass and arterial stiffness. There were no study-related serious adverse events. CONCLUSIONS: In older obese heart failure with preserved ejection fraction patients, CR+AT produces large improvements in VO2peak and quality-of-life. Adding RT to CR+AT increased leg strength and muscle quality without attenuating skeletal muscle loss or further increasing VO2peak or quality-of-life. REGISTRATION: URL: https://ClincalTrials.gov; Unique identifier: NCT02636439.

Differences in Health-Related Quality of Life in Older People with and without Sarcopenia Covered by Long-Term Care Insurance.

Background: As a result of the increase in older people covered by long-term care insurance (LTCI), prevention of sarcopenia and maintenance and improvement of health-related quality of life (HRQOL) have become important themes. This study aimed to clarify both the differences in HRQOL in older people with and without sarcopenia covered by LTCI and the correlation between HRQOL and physical function. Methods: Participants were 101 older people with LTCI at a daycare center in Japan. We investigated clinical factors using the EuroQol five-dimension three-level questionnaire (EQ-5D-3L). Analysis was by unpaired t-test, Mann−Whitney U test, chi-square test, analysis of covariance, Pearson's correlation coefficient, and Spearman's rank correlation coefficient. Results: Compared to the no sarcopenia group (n = 40), the sarcopenia group (n = 24) had significantly lower body mass index, skeletal muscle mass index, gait speed, EQ-5D-3L, and adjusted EQ-5D-3L (p < 0.05). The EQ-5D-3L showed a significant correlation with handgrip strength in the sarcopenia group (p = 0.02) and significant correlations with gait speed and one-leg standing time (both, p = 0.01) in the no sarcopenia group. Conclusion: We clarified differences in HRQOL in older people with and without sarcopenia covered by LTCI. This information on the interrelationship between HRQOL and physical function may help maintain and improve HRQOL in these people.

Evaluation of a blood-based geroscience biomarker index in a randomized trial of caloric restriction and exercise in older adults with heart failure with preserved ejection fraction.

Intermediate endpoints are needed to evaluate the effect of interventions targeting the biology of aging in clinical trials. A working group identified five blood-based biomarkers that may serve such a purpose as an integrated index. We evaluated the responsiveness of the panel to caloric restriction or aerobic exercise in the context of a randomized clinical trial conducted in patients with heart failure with preserved ejection fraction (HFpEF) with obese phenotype who were predominantly female. Obese HFpEF is highly prevalent in women, and is a geriatric syndrome whose disease pathology is driven by non-cardiac factors and shared drivers of aging. We measured serum Interleukin-6, TNF-α-receptor-I, growth differentiating factor-15, cystatin C, and N-terminal pro-b-type natriuretic peptide at baseline and after 20 weeks in older participants with stable obese HFpEF participating in a randomized, controlled, 2 × 2 factorial trial of caloric restriction and/or aerobic exercise. We calculated a composite biomarker index, summing baseline quintile scores for each biomarker, and analyzed the effect of the interventions on the index and individual biomarkers and their associations with changes in physical performance. This post hoc analysis included 88 randomized participants (71 women [81%]). The mean ± SD age was 66.6 ± 5.3 years, and body mass index (BMI) was 39.3 ± 6.3 kg/m2. Using mixed models, mean values of the biomarker index improved over 20 weeks with caloric restriction (- 0.82 [Formula: see text] 0.58 points, p = 0.05), but not with exercise (- 0.28 [Formula: see text] 0.59 points, p = [Formula: see text]), with no evidence of an interaction effect of CR [Formula: see text] EX [Formula: see text] time (p = 0.80) with adjustment for age, gender, and BMI. At baseline, the biomarker index was inversely correlated with 6-min walk distance, scores on the short physical performance battery, treadmill test peak workload and exercise time to exhaustion (all [Formula: see text] s = between - 0.21 and - 0.24). A reduction in the biomarker index was also associated with increased 4-m usual walk speed ([Formula: see text] s = - 0.31). Among older patients with chronic obese HFpEF, caloric restriction improved a biomarker index designed to reflect biological aging. Moreover, the index was associated with physical performance and exercise tolerance.

Left Atrial Stiffness Index Independently Predicts Exercise Intolerance and Quality of Life in Older, Obese Patients With Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is the fastest growing form of HF and is associated with high morbidity and mortality. The primary chronic symptom in HFpEF is exercise intolerance, associated with reduced quality of life. Emerging evidence implicates left atrial (LA) dysfunction as an important pathophysiologic mechanism. Here we extend prior observations by relating LA dysfunction to peak oxygen uptake (peak VO2), physical function (distance walked in 6 minutes [6MWD]) and quality of life (Kansas City Cardiomyopathy Questionnaire). METHODS AND RESULTS: We compared 75 older, obese, patients with HFpEF with 53 healthy age-matched controls. LA strain was assessed by magnetic resonance cine imaging using feature tracking. LA function was defined according to its 3 distinct phases, with the LA serving as a reservoir during systole, as a conduit during early diastole, and as a booster pump at the end of diastole. The LA stiffness index was calculated as the ratio of early mitral inflow velocity-to-early annular tissue velocity (E/e', by Doppler ultrasound examination) and LA reservoir strain. HFpEF had a decreased reservoir strain (16.4 ± 4.4% vs 18.2 ± 3.5%, P = .018), lower conduit strain (7.7 ± 3.3% vs 9.1 ± 3.4%, P = .028), and increased stiffness index (0.86 ± 0.39 vs 0.53 ± 0.18, P < .001), as well as decreased peak VO2, 6MWD, and lower quality of life. Increased LA stiffness was independently associated with impaired peak VO2 (ß = 9.0 ± 1.6, P < .001), 6MWD (ß = 117 ± 22, P = .003), and Kansas City Cardiomyopathy Questionnaire score (ß = -23 ± 5, P = .001), even after adjusting for clinical covariates. CONCLUSIONS: LA stiffness is independently associated with impaired exercise tolerance and quality of life and may be an important therapeutic target in obese HFpEF. REGISTRATION: NCT00959660.

The importance of healthy lifestyle behaviors in the prevention of cardiovascular disease.

Cardiovascular disease (CVD) is the leading cause of death globally. Advancements in the treatment of CVD have reduced mortality rates, yet the global burden of CVD remains high. Considering that CVD is still largely a preventable disease, prioritizing preventative measures through healthy lifestyle (HL) behaviors is necessary to lessen the burden of CVD. HL behaviors, such as regular exercise, healthy eating habits, adequate sleep, and smoking cessation, can influence a number of traditional CVD risk factors as well as a less commonly measured risk factor, cardiorespiratory fitness (CRF). It is important to note that cardiac rehabilitation programs, which traditionally have focused on secondary prevention, also emphasize the importance of making comprehensive HL behavior changes. This review discusses preventative measures to reduce the burden of CVD through an increased uptake and assessment of HL behaviors. An overview of the importance of CRF as a risk factor is discussed along with how to improve CRF and other risk factors through HL behavior interventions. The role of the clinician for promoting HL behaviors to prevent CVD is also reviewed.

Physical Activity, Coronary Artery Calcium, and Cardiovascular Outcomes in the Multi-Ethnic Study of Atherosclerosis (MESA).

INTRODUCTION: Although the inverse relationship between physical activity (PA) and cardiovascular disease (CVD) is well established, observational studies suggest that very high levels of PA may be harmful. This study sought to understand the relationship between PA, coronary artery calcium (CAC), and cardiovascular outcomes among individuals at different levels of risk. METHODS: PA and CAC were assessed in 6777 baseline participants of the Multi-Ethnic Study of Atherosclerosis. Total PA in MET-minutes per week was categorized into quartiles, and CAC was categorized as "low risk" (<100 Agatston units; n = 5180) and "high risk" (≥100 Agatston units; n = 1597). Cox proportional hazard regression analyses and Kaplan-Meier curves were generated to understand relationships between PA and CAC with CVD and all-cause mortality. RESULTS: In low-risk participants in the highest PA quartile, there was a decrease in the adjusted hazard ratio (HR) for CVD (HR, 0.72; 95% confidence interval (CI), 0.56-0.94) and all-cause mortality (HR, 0.69; 95% CI, 0.57-0.84) compared with those in the lowest PA quartile. In high-risk participants in the highest PA quartile, there was a decrease in the adjusted HR for all-cause mortality (HR, 0.59; 95% CI, 0.47-0.74) compared with those in the lowest PA quartile. High PA was not associated with an increased risk of either outcome, regardless of CAC category, sex, or race/ethnicity. CONCLUSIONS: Our research suggests that there is no increased risk associated with high levels of PA, even among individuals at high risk of CVD.

Impact of cardiac surgery-associated acute kidney injury on activities of daily living at discharge in elderly cardiac surgery patients.

Cardiac surgery-associated acute kidney injury (CSA-AKI) is a critical complication associated with mortality and morbidity. This study aimed to clarify the impact of CSA-AKI on activities of daily living (ADL) at discharge in elderly cardiac surgery patients. We included 122 cardiac patients who underwent coronary artery bypass surgery, valve surgery, or combined surgery by mid-line incision followed by postoperative cardiac rehabilitation (CR) from March 2015 to May 2020. CSA-AKI was based on KDIGO criteria. The index of ADL was the Functional Independence Measure (FIM). We compared background factors, clinical parameters, activity level before hospitalization, CR progress, and FIM in patients with or without CSA-AKI. Multiple regression analysis was performed with FIM at discharge as the dependent variable and items with p < 0.01 in bivariate correlation as independent variables. Ultimately, 122 patients were divided into the non-CSA-AKI group (n = 84) and CSA-AKI group (n = 38). CR progression in the CSA-AKI group was significantly slower and FIM was lower than that in the non-CSA-AKI group. Moreover, even after adjustment for confounding factors, CSA-AKI (ß = -0.18), start day of walking (ß = -0.34), postoperative atrial fibrillation (ß = -0.15), and activity level before hospitalization (ß = -0.37) were predictive factors of ADL decline at discharge (adjusted R2 = 0.52). CSA-AKI of elderly cardiac surgery patients was a predictive factor of ADL decline at discharge.

Exercise training for prevention and treatment of older adults with heart failure with preserved ejection fraction.

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most rapidly increasing form of HF, occurs primarily in older women, and is associated with high rates of morbidity, mortality, and health care expenditures. In the highest age decile (≥90 years old), nearly all patients with HFpEF. As our understanding of the disease has grown in the last few years, we now know that HFpEF is a systemic disorder influenced by aging processes. The involvement of this broad collection of abnormalities in HFpEF, the recognition of the high frequency and impact of noncardiac comorbidities, and systemic, multiorgan involvement, and its nearly exclusive existence in older persons, has led to the recognition of HFpEF as a true geriatric syndrome. Most of the conventional therapeutics used in other cardiac diseases have failed to improve HFpEF patient outcomes significantly. Several recent studies have evaluated exercise training (ET) as a therapeutic management strategy in patients with HFpEF. Although these studies were not designed to address clinical endpoints, such as HF hospitalizations and mortality, they have shown that ET is a safe and effective intervention to improve peak oxygen consumption, physical function, and quality of life in clinically stable HF patients. Recently, a progressive, multidomain physical rehabilitation study among older adults showed that it is feasible in older patients with acute decompensated HF who have high frailty and comorbidities and showed improvement in physical function. However, the lack of Centers for Medicare and Medicaid Services coverage can be a major barrier to formal cardiac rehabilitation in older HFpEF patients. Unfortunately, insistence upon demonstration of mortality improvement before approving reimbursement overlooks the valuable and demonstrated benefits of physical function and life quality.

Comparison of Different Functional Tests for Leg Power and Normative Bilateral Asymmetry Index in Healthy Collegiate Athletes.

BACKGROUND: Bilateral leg power is being increasingly investigated as a proxy for the recovery of muscle performance after injury. Functional tests like the single leg hop for distance (SLHD) and single leg vertical jump (SLVJ) are often used to determine symmetry and return to play (RTP) readiness. As an injury predictor, leg power is accurately measured with the Keiser Air420 seated leg press. PURPOSE: To measure and analyze lower leg asymmetry in healthy collegiate athletes across each test battery. METHODS: Eighty-eight healthy student-athletes (44 males, 44 females) across 14 varsity teams at Wake Forest University performed the SLHD, SLVJ, and the Keiser. Horizontal and vertical displacement were measured via the SLHD and SLVJ, respectively. Peak power was recorded via the Keiser Air420 leg press. Pearson correlations and repeated measures ANOVA were used to calculate associations and compare bilateral asymmetry indices (BAI) and raw scores. RESULTS: There was a significant effect on each test's raw BAI (P < 0.01). The mean absolute BAI were 5.42 ± 4.9%, 6.64 ± 4.9% and 5.36 ± 4.7% for the SLHD, SLVJ and Keiser, respectively. The SLVJ and Keiser (dominant leg r = 0.832, nondominant leg r = 0.826) were more highly correlated than the SLHD and Keiser (dominant leg r = 0.645, nondominant leg r = 0.687), all of which were statistically significant (P < 0.01). CONCLUSION: At the 90th percentile, healthy collegiate athletes attained <15% BAI. We recommend the implementation of a battery of tests to determine normative lower limb asymmetry. A battery of functional tests may present different asymmetry indices as opposed the 10% reference asymmetry.

Relationships Between Objectively Measured Physical Activity, Exercise Capacity, and Quality of Life in Older Patients With Obese Heart Failure and Preserved Ejection Fraction.

BACKGROUND: The relationship between physical activity (PA), exercise capacity, and quality of life (QOL) in obese heart failure with preserved ejection fraction is poorly understood. METHODS AND RESULTS: This was an ancillary study to a clinical trial. Accelerometers were used to measure light PA, moderate to vigorous PA, total PA, PA energy expenditure, and steps. Peak VO2, exercise time, and 6-minute walk distance, as well as QOL measures were obtained. Pearson correlations were performed to examine relationships between PA, exercise capacity, and QOL. Patients (n = 58) were 68.0 ± 5.7 years old, 78% female, 59% White, and obese (body mass index 39.1 ± 6.1 kg/m2). Patients had low levels of objectively measured PA as well as decreased exercise capacity and poor QOL. Light PA (r = 0.32, P = .014) and steps per day (r = 0.30, P = .022) were modestly correlated with peak VO2. All PA variables were modestly correlated with exercise time (r = 0.33-0.49, all P < .02) and 6-minute walk distance (r = 0.25-0.48, all P < .01). None of the PA variables were correlated with QOL. CONCLUSIONS: PA variables were modestly correlated with measures of exercise capacity and were not significantly correlated with QOL. Our findings indicate that PA, exercise capacity, and QOL assess different aspects of the patient experience in older obese patients with heart failure with preserved ejection fraction.

Relationship of end-tidal oxygen partial pressure to the determinants of anaerobic threshold in post-myocardial infarction patients.

The anaerobic threshold (AT), obtained during cardiopulmonary exercise testing (CPET), is an important prognostic measure and can be used to develop an exercise prescription in patients after a myocardial infarction (post-MI). The purpose of this study was to examine the central and peripheral determinants of AT in post-MI patients end-tidal oxygen partial pressure (PETO2) measures. We performed cardiopulmonary exercise testing (CPET) on 148 consecutively enrolled post-MI patients to determine PETO2 measured at the AT (AT PETO2) and ΔPETO2 (difference between resting PETO2 and AT PETO2). We subsequently investigated the relationship between these measures of PETO2 and the individual AT for each patient. Multivariate linear regression analysis indicated that AT PETO2 and ΔPETO2 were independently and significantly associated with the AT (ß = -0.344, p < 0.001 and ß = 0.228, p < 0.001, respectively). Furthermore, the independent factors of AT PETO2 were left ventricular ejection fraction (p = 0.005), resting ventilatory equivalent for carbon dioxide (p = 0.002), and resting dead-space gas volume to tidal volume ratio (p < 0.001). However, the independent factors for ΔPETO2 were history of diabetes (p = 0.047), estimated glomerular filtration rate (p = 0.001), and resting systolic blood pressure (p = 0.017). These findings suggested that AT PETO2 was associated with central determinants; whereas, and ΔPETO2 was associated with peripheral determinants, The AT PETO2 and ΔPETO2 provide variable insight regarding the cause of exercise intolerance and can be used to determine appropriate therapies.