Effect of high intensity exercise training on central hemodynamic responses to exercise in men with reduced left ventricular function

Cardiac hemodynamics phenotypes and individual responses to training in coronary heart disease patients

BACKGROUND

In patients with coronary heart disease (CHD), individualized exercise training (ET) programs are strongly recommended to optimize peak oxygen uptake (V ̇ $$ \dot{\mathrm{V}} $$ O2peak) improvement and prognosis. However, the cardiac hemodynamic factors responsible for a positive response to training remain unclear. The aim of this study was to compare cardiac hemodynamic changes after an ET program in responder (R) versus non-responder (NR) CHD patients.

METHODS

A total of 72 CHD patients completed a 3-month ET program and were assessed by cycle ergometer cardiopulmonary exercise test (CPET:V ̇ $$ \dot{\mathrm{V}} $$ O2peak assessment) with impedance cardiography (ICG) for hemodynamic measurements before and after training. Cardiac hemodynamics (e.g., CO, CI, SV, ESV, EDV, and SVR) were measured by ICG during CPET. The R and NR groups were classified using the median change inV ̇ $$ \dot{\mathrm{V}} $$ O2peak (>the median for R and ≤the median for NR).

RESULTS

In the R group,V ̇ $$ \dot{\mathrm{V}} $$ O2peak (+17%, p < 0.001), CO, CI, SV, and HR increased by 17%, 17%, 13%, and 5%, respectively (p < 0.05) after the training program. In the NR group,V ̇ $$ \dot{\mathrm{V}} $$ O2peak, CO, CI, and SV increased by 0.5%, 5%, 8%, and 6%, respectively (p < 0.01). The SVR decreased in both groups (-19% in R and -11% in NR, p < 0.001).

CONCLUSION

Among CHD patients, the R group showed a better improvement in peak cardiac output via an increase in peak stroke volume and heart rate and a reduced systemic vascular resistance than the NR group. Different cardiac phenotype adaptations and clinical individual responses were identified in CHD patients according to the aerobic fitness responder's status.

Exercise-based cardiac rehabilitation for left ventricular function in patients with heart failure: A systematic review and meta-analysis

AIMS

To evaluate the effect of exercise rehabilitation on the left ventricular (LV) function in patients with heart failure (HF).

METHODS

PubMed, Cochrane Library and Embase were searched until May 2023. Randomized controlled trials (RCTs) providing data on changes in LV function, comparing exercise to no-exercise controls with HF of any type, were included.

RESULTS

A total of 16 studies including 1443 participants were included. LV end-diastolic diameter (LVEDD) was significantly improved in the exercise group [mean differences (MD), -2.67; 95 % confidence interval (CI) (-4.88, -0.46); P=0.02], but left atrial volume index (LAVI), left ventricular end-systolic diameter (LVESD), E/e' E/A, end-diastolic volume (EDV), end-systolic volume (ESV), left ventricular ejection fraction (LVEF) and LV mass were unaltered compared to the non-exercise group. High intensity interval training (HIIT) or with moderate exercise (MT) led to improvement in LVEDD [MD, 3.62; 95 %CI (2.55, 4.69); P<0.00001], but not LAVI, E/e' and E/A. Sensitivity and subgroup analyses showed that the location, the type of HF and study duration may be the source of heterogeneity in LVEF. Age appears to be a source of heterogeneity in EDV and ESV. The Egger test indicated no significant publication bias.

CONCLUSIONS

Exercise can partially improve LV function in patients with HF, with improvements appearing to be dependent on study quality, the type of HF, and race. However, there are some indicators that do not seem to improve or are even worse than the control group. Among all exercise modalities, HIIT shows the greatest benefit for HF patients.

Standardised Exercise Prescription for Patients with Chronic Coronary Syndrome and/or Heart Failure: A Consensus Statement from the EXPERT Working Group

Whereas exercise training, as part of multidisciplinary rehabilitation, is a key component in the management of patients with chronic coronary syndrome (CCS) and/or congestive heart failure (CHF), physicians and exercise professionals disagree among themselves on the type and characteristics of the exercise to be prescribed to these patients, and the exercise prescriptions are not consistent with the international guidelines. This impacts the efficacy and quality of the intervention of rehabilitation. To overcome these barriers, a digital training and decision support system [i.e. EXercise Prescription in Everyday practice & Rehabilitative Training (EXPERT) tool], i.e. a stepwise aid to exercise prescription in patients with CCS and/or CHF, affected by concomitant risk factors and comorbidities, in the setting of multidisciplinary rehabilitation, was developed. The EXPERT working group members reviewed the literature and formulated exercise recommendations (exercise training intensity, frequency, volume, type, session and programme duration) and safety precautions for CCS and/or CHF (including heart transplantation). Also, highly prevalent comorbidities (e.g. peripheral arterial disease) or cardiac devices (e.g. pacemaker, implanted cardioverter defibrillator, left-ventricular assist device) were considered, as well as indications for the in-hospital phase (e.g. after coronary revascularisation or hospitalisation for CHF). The contributions of physical fitness, medications and adverse events during exercise testing were also considered. The EXPERT tool was developed on the basis of this evidence. In this paper, the exercise prescriptions for patients with CCS and/or CHF formulated for the EXPERT tool are presented. Finally, to demonstrate how the EXPERT tool proposes exercise prescriptions in patients with CCS and/or CHF with different combinations of CVD risk factors, three patient cases with solutions are presented.

Skeletal muscle and heart failure - What is the relationship between central versus peripheral affections?

BACKGROUND AND AIM

Heart failure is considered as a systemic disease as beside the heart, skeletal muscle is affected.

METHODS AND RESULTS

In this retrospective case-control study 64 men and 15 women with heart failure as well as an individually pairwise matched sample by sex, age and body mass index of healthy individuals from the COmPLETE cohort study performed an exhaustive cardiopulmonary exercise test, strength tests and anthropometric measurements. V̇O2peak was 28.6% lower in male and 24.6% lower in female patients with heart failure as compared to healthy controls. Strength parameters are significantly higher for counter movement jump in male subjects. In females, significant differences were detected for mid-thigh pull in healthy versus patients with heart failure. Skeletal muscle mass of patients was in male as well as female 3.7% lower than in controls. Furthermore, the function of skeletal muscle seems impaired as the ability to accelerate is significantly lower in affected male with a heart pathology.

CONCLUSION

It seems that severe affections (approx. 25 to 30%) on cardiocirculatory level are associated with moderate to low affections on functional and structural capacity on skeletal muscle level. Further, as in the male cohort with a heart pathology acceleration meaning 'fast' contracting is impaired, it is suggested, that the central limitations respectively the low perfusion of skeletal muscle over years yield to adaptions on muscle cell level ingoing with a decreased ability of fast contracting. It is therefore suggested, that the central circulatory limitations in patients with heart failure, respectively the low perfusion of skeletal muscle over years, promote maladaptation's in the periphery.

The treatment of chronic anemia in heart failure: a global approach

Chronic anemia is an independent risk factor for mortality in patients with heart failure (HF). Restoring physiological hemoglobin (Hb) levels is essential to increase oxygen transport capacity to tissues and improve cell metabolism as well as physical and cardiac performance. Nutritional deficits and iron deficiency are the major causes of chronic anemia, but other etiologies include chronic kidney disease, inflammatory processes, and unexplained anemia. Hormonal therapy, including erythropoietin (EPO) and anabolic treatment in chronic anemia HF patients, may contribute to improving Hb levels and clinical outcomes. Although preliminary studies showed a beneficial effect of EPO therapy on cardiac efficiency and in HF, more recent studies have not confirmed this positive impact of EPO, alluding to its side effect profile. Physical exercise significantly increases Hb levels and the response of anemia to treatment. In malnourished patients and chronic inflammatory processes, low levels of anabolic hormones, such as testosterone and insulin-like growth factor-1, contribute to the development of chronic anemia. This paper aims to review the effect of nutrition, EPO, anabolic hormones, standard HF treatments, and exercise as regulatory mechanisms of chronic anemia and their cardiovascular consequences in patients with HF.

The Acute and Chronic Effects of Resistance and Aerobic Exercise in Hemostatic Balance: A Brief Review

Hemostatic balance refers to the dynamic balance between blood clot formation (coagulation), blood clot dissolution (fibrinolysis), anticoagulation, and innate immunity. Although regular habitual exercise may lower the incidence of cardiovascular diseases (CVD) by improving an individual’s hemostatic profile at rest and during exertion, vigorous exercise may increase the risk of sudden cardiac death and venous thromboembolism (VTE). This literature review aims to investigate the hemostatic system’s acute and chronic adaptive responses to different types of exercise in healthy and patient populations. Compared to athletes, sedentary healthy individuals demonstrate similar post-exercise responses in platelet function and coagulatory and fibrinolytic potential. However, hemostatic adaptations of patients with chronic diseases in regular training is a promising field. Despite the increased risk of thrombotic events during an acute bout of vigorous exercise, regular exposure to high-intensity exercise might desensitize exercise-induced platelet aggregation, moderate coagulatory parameters, and up-regulate fibrinolytic potential via increasing tissue plasminogen activator (tPA) and decreasing plasminogen activator inhibitor (PAI-1) response. Future research might focus on combining different types of exercise, manipulating each training characteristic (frequency, intensity, time, and volume), or investigating the minimal exercise dosage required to maintain hemostatic balance, especially in patients with various health conditions.

Impact of training on combined cardiopulmonary exercise test with stress echocardiography parameters in HFrEF patients

BACKGROUND

Exercise-based cardiac rehabilitation is recognized to improve quality of life in heart failure patients. However, the effects on the cardiac function are understudied. The main objective was to assess the impact of a 4-week cardiac rehabilitation program on cardiopulmonary exercise testing (CPET) combined with simultaneous echocardiography parameters in chronic heart failure (CHF) patients. The secondary aim was to investigate patients' responses to training.

METHODS

Forty-one CHF patients with reduced ejection fraction (29.3 ± 0.1%) underwent CPET and stress echocardiography before and after a 4-week of exercise-training program. Blood parameters, echocardiography and cardiopulmonary parameters were assessed before and after training. Potential echocardiography derived predictive parameters like left and right contractile reserves, left ventricle elastance, end systolic volume and right ventricle S wave response to exercise were also assessed.

RESULTS

The training program increased the peak oxygen consumption (VO₂) (P < 0.001), the peak systolic blood pressure, the left ventricular outflow tract velocity time integral (P < 0.05) and the circulatory (P < 0.001) and ventilatory (P < 0.01) powers. It also decreased the VE/VCO₂ slope (P < 0.001). As the median value of peak VO₂ gain was 17%, patients above this value were considered as responders and patients below as non-responders to training. The responders presented a higher left ventricle contractile reserve compared to non-responder patients. The peak left ventricle elastance and peak right ventricle S wave response tended to be higher in responders.

CONCLUSION

Combination of CPET and stress echocardiography may contribute to establish the disease severity stratification and to predict response to training in CHF patients with reduced ejection fraction.

Cardiac rehabilitation in heart failure with severely reduced ejection fraction: effects on mortality

Thirty years ago, patients with low ejection fraction (EF) have often been excluded from rehabilitation programs due to concern about possibility of sudden death or other adverse cardiovascular events during exercise sessions. Recent studies have highlighted the fact that cardiac rehabilitation could improve exercise capacity, cardiac function, and health-related quality of life in congestive heart failure patients. This encouraged us to write a review article and update our latest knowledge about the outcome of rehabilitation program in patients with severely depressed cardiac function. We were particularly interested in effect of cardiac rehabilitation on exercise capacity, quality of life, vascular effects, neuro-hormonal changes, and mortality. We also conducted a mini-systematic review and meta-analysis on randomized controlled trials comparing exercise training with usual care in patients with severely reduced left ventricular ejection fraction, for the mortality subsection to obtain precise estimates of overall treatment benefit on mortality. It is our privilege to submit our manuscript for possible publication in your prestigious journal.

Average and Interindividual Effects to a Comprehensive Cardiovascular Rehabilitation Program

Background: To describe the average effects and the interindividual variability after a comprehensive outpatient cardiovascular rehabilitation (CCR) program using concurrent exercise training prescribed according to cardiovascular risk stratification on cardiorespiratory fitness (CRF), anthropometric/body composition, quality of life and emotional health in patients of four cardiovascular disease profiles. Methods: CRF, anthropometric/body composition, quality of life, and emotional health were measured before and after a CCR and analyzed in heart valve surgery (HVS), heart failure with reduced ejection fraction (HFrEF), post-acute myocardial infarction (post-AMI), and in coronary artery disease (CAD) patients. Twenty, twenty-four, and thirty-two exercise sessions were prescribed according to mild, moderate, and severe baseline cardiovascular risk, respectively. In addition to concurrent exercise training, nutritional counseling, psychological support, and lifestyle education programs were performed. Results: The main outcomes by delta changes comparisons (Δ) revealed no significant differences at anthropometric/body composition as ΔBody fat decreases (HVS Δ−1.1, HFrEF Δ−1.0, post-AMI Δ−1.4, CAD Δ−1.2 kg) and ΔSkeletal muscle mass increases (HVS Δ+1.4, HFrEF Δ+0.8, post-AMI Δ+0.9, CAD Δ+0.9 kg), and CRF performance as ΔVO2peak increases (HVS Δ+4.3, HFrEF Δ+4.8, post-AMI Δ+4.1, CAD Δ+5.1 mL/kg/min) outcomes among HVS, HFrEF, post-AMI, and CAD (p > 0.05). Secondary outcomes showed significant pre-post delta changes in METs (HVS Δ+1.8, HFrEF Δ+0.7, post-AMI Δ+1.4, CAD Δ+1.4), and maximal O2pulse (HVS Δ+3.1, post-AMI Δ+2.1, CAD Δ+1.9). In addition, quality of life had a significant improvement in physical functioning (HVS Δ+17.0, HFrEF Δ+12.1, post-AMI Δ+9.8, CAD Δ+11.2), physical role (HVS Δ+28.4, HFrEF Δ+26.8, post-AMI Δ+25.6, CAD Δ+25.3), vitality (HVS Δ+18.4, HFrEF Δ+14.3, post-AMI Δ+14.2, CAD Δ+10.6) and social functioning (HVS Δ+20.4, HFrEF Δ+25.3, post-AMI Δ+20.4, CAD Δ+14.8) in all cardiovascular disease. For anxiety (HVS Δ−3.6, HFrEF Δ−2.3, post-AMI Δ−3.0, CAD Δ−3.1) and depression (HVS Δ−2.8, HFrEF Δ−3.4, post-AMI Δ−3.2, CAD Δ−2.3) significant changes were also observed. Conclusions: A CCR program that prescribes the number of exercise sessions using a cardiovascular risk stratification improves CRF, QoL, and emotional health, and the average results show a wide interindividual variability (~25% of non-responders) in this sample of four CVD profile of patients.

Effects of exercise-based cardiac rehabilitation delivery modes on exercise capacity and health-related quality of life in heart failure: a systematic review and network meta-analysis

Background

This review aimed to compare the relative effectiveness of different exercise-based cardiac rehabilitation (ExCR) delivery modes (centre-based, home-based, hybrid and technology-enabled ExCR) on key heart failure (HF) outcomes: exercise capacity, health-related quality of life (HRQoL), HF-related hospitalisation and HF-related mortality.

Methods and results

Randomised controlled trials (RCTs) published through 20 June 2021 were identified from six databases, and reference lists of included studies. Risk of bias and certainty of evidence were evaluated using the Cochrane tool and Grading of Recommendations Assessment, Development and Evaluation, respectively. Bayesian network meta-analysis was performed using R. Continuous and binary outcomes are reported as mean differences (MD) and ORs, respectively, with 95% credible intervals (95% CrI). One-hundred and thirty-nine RCTs (n=18 670) were included in the analysis. Network meta-analysis demonstrated improvements in VO₂peak following centre-based (MD (95% CrI)=3.10 (2.56 to 3.65) mL/kg/min), home-based (MD=2.69 (1.67 to 3.70) mL/kg/min) and technology-enabled ExCR (MD=1.76 (0.27 to 3.26) mL/kg/min). Similarly, 6 min walk distance was improved following hybrid (MD=84.78 (31.64 to 138.32) m), centre-based (MD=50.35 (30.15 to 70.56) m) and home-based ExCR (MD=36.77 (12.47 to 61.29) m). Incremental shuttle walk distance did not improve following any ExCR delivery modes. Minnesota living with HF questionnaire improved after centre-based (MD=−10.38 (−14.15 to –6.46)) and home-based ExCR (MD=−8.80 (−13.62 to –4.07)). Kansas City Cardiomyopathy Questionnaire was improved following home-based ExCR (MD=20.61 (4.61 to 36.47)), and Short Form Survey 36 mental component after centre-based ExCR (MD=3.64 (0.30 to 6.14)). HF-related hospitalisation and mortality risks reduced only after centre-based ExCR (OR=0.41 (0.17 to 0.76) and OR=0.42 (0.16 to 0.90), respectively). Mean age of study participants was only associated with changes in VO₂peak.

Conclusion

ExCR programmes have broader benefits for people with HF and since different delivery modes were comparably effective for improving exercise capacity and HRQoL, the selection of delivery modes should be tailored to individuals’ preferences.

Mechanisms of Exercise Capacity Improvement after Cardiac Rehabilitation Following Myocardial Infarction Assessed with Combined Stress Echocardiography and Cardiopulmonary Exercise Testing

Cardiac rehabilitation (CR) is indicated in all patients after acute myocardial infarction (AMI) to improve prognosis and exercise capacity (EC). Previous studies reported that up to a third of patients did not improve their EC after CR (non-responders). Our aim was to assess the cardiac and peripheral mechanisms of EC improvement after CR using combined exercise echocardiography and cardiopulmonary exercise testing (CPET-SE). The responders included patients with an improved EC assessed as a rise in peak oxygen uptake (VO₂) ≥ 1 mL/kg/min. Peripheral oxygen extraction was calculated as arteriovenous oxygen difference (A-VO₂Diff). Out of 41 patients (67% male, mean age 57.5 ± 10 years) after AMI with left ventricular ejection fraction (LVEF) ≥ 40%, 73% improved their EC. In responders, peak VO₂ improved by 27% from 17.9 ± 5.2 mL/kg/min to 22.7 ± 5.1 mL/kg/min, p < 0.001, while non-responders had a non-significant 5% decrease in peak VO₂. In the responder group, the peak exercise heart rate, early diastolic myocardial velocity at peak exercise, LVEF at rest and at peak exercise, and A-VO₂Diff at peak exercise increased, the minute ventilation to carbon dioxide production slope decreased, but the stroke volume and cardiac index were unchanged after CR. Non-responders had no changes in assessed parameters. EC improvement after CR of patients with preserved LVEF after AMI is associated with an increased heart rate response and better peripheral oxygen extraction during exercise.

Effect of aerobic exercise on physiological and left ventricular echocardiographic characteristics of non-athletic adult males in Northern Ethiopia

BACKGROUND

Regular aerobic exercise can induce alterations in structural and hemodynamic physiology of the heart in both athletic and nonathletic populations. This is because due to cardiac adaptation to exercise improves cardiac workout capacity by increasing left ventricular function. The aim of the present study was to examine the effect of aerobic exercise on blood pressure and left ventricular structural and myocardial function in Ethiopian non-athletic males.

METHODS

Twenty male adults (aged 19-23 years) were recruited and they were engaged in aerobic exercise training for 3 months (3days/week, 50-75%MHR). Selected participants underwent standard transthoracic doppler echocardiographic examinations before and after intervention of the exercise training. Collected data were analyzed through Paired Sample T test using IBM SPSS version 21 statistical software with significance level set at p<0.05.

RESULTS

Finding of the study indicated that significant reduction in systolic and diastolic blood pressure was observed after exercise training (p<0.05). Improvement was recorded in PWT (7.4±0.94mm vs 7.95±0.61mm, p=0.017) and IVST (7.95±0.83mm vs 8.25±0.72mm, p=0.030) while significant reduction was recorded in LVIDS (33.85±0.99mm vs 32.45±2.04mm, p=0.002). Aerobic exercises also induced significant improvement on left ventricular myocardial function parameters (p<0.05) in end diastolic volume (95.8±8.4ml vs 100.45±11.42ml), stroke volume (52.55±7.12ml vs 58.15±11.18ml) and ejection fraction (54.73±4.11 vs 57.53±6.2). However, exercise didn't stimulate significant change in the internal diameter at end diastole (0.086), end systolic volume (p=0.173) and cardiac output (p=0.13).

CONCLUSIONS

Aerobic exercise induces structural and myocardial physiological changes within the left ventricle in Ethiopian non-athletic young adult males.

The venous contribution to cardiovascular performance: From systemic veins to left ventricular function: A review

The venous system contains ≈ 70 % of the total blood volume and is responsible in heart failure for key symptoms of congestion. It is active: it can increase or relax its tone with physiologic or pharmacologic stimuli. It is heterogeneous, behaves as a two-compartment model, compliant (splanchnic veins) and noncompliant (nonsplanchnic veins). It is dynamic in health and disease: in heart failure the vascular capacitance (storage space) is decreased and can result in volume redistribution from the abdominal compartment to the thoracic compartment (heart and lungs), which increases pulmonary pressures and precipitates pulmonary congestion. A noninvasive assessment of venous function, at rest and dynamically during stress, is warranted. The systemic haemodynamic congestion is assessed with inferior vena cava diameter and collapsibility. The pulmonary congestion is assessed with B-lines and pleural effusion. The contribution of left ventricular filling is assessed with end-diastolic volume, integrated with left ventricular function.

Exercise-based cardiac rehabilitation for chronic heart failure: the EXTRAMATCH II individual participant data meta-analysis

BACKGROUND

Current national and international guidelines on the management of heart failure (HF) recommend exercise-based cardiac rehabilitation (ExCR), but do not differentiate this recommendation according to patient subgroups.

OBJECTIVES

(1) To obtain definitive estimates of the impact of ExCR interventions compared with no exercise intervention (control) on mortality, hospitalisation, exercise capacity and health-related quality of life (HRQoL) in HF patients; (2) to determine the differential (subgroup) effects of ExCR in HF patients according to their age, sex, left ventricular ejection fraction, HF aetiology, New York Heart Association class and baseline exercise capacity; and (3) to assess whether or not the change in exercise capacity mediates for the impact of the ExCR on final outcomes (mortality, hospitalisation and HRQoL), and determine if this is an acceptable surrogate end point.

DESIGN

This was an individual participant data (IPD) meta-analysis.

SETTING

An international literature review.

PARTICIPANTS

HF patients in randomised controlled trials (RCTs) of ExCR.

INTERVENTIONS

ExCR for at least 3 weeks compared with a no-exercise control, with 6 months' follow-up.

MAIN OUTCOME MEASURES

All-cause and HF-specific mortality, all-cause and HF-specific hospitalisation, exercise capacity and HRQoL.

DATA SOURCES

IPD from eligible RCTs.

REVIEW METHODS

RCTs from the Exercise Training Meta-Analysis of Trials for Chronic Heart Failure (ExTraMATCH/ExTraMATCH II) IPD meta-analysis and a 2014 Cochrane systematic review of ExCR (Taylor RS, Sagar VA, Davies EJ, Briscoe S, Coats AJ, Dalal H, et al. Exercise-based rehabilitation for heart failure. Cochrane Database Syst Rev 2014;4:CD003331).

RESULTS

Out of the 23 eligible RCTs (4398 patients), 19 RCTs (3990 patients) contributed data to this IPD meta-analysis. There was a wide variation in exercise programme prescriptions across included studies. Compared with control, there was no statistically significant difference in pooled time-to-event estimates in favour of ExCR, although confidence intervals (CIs) were wide: all-cause mortality had a hazard ratio (HR) of 0.83 (95% CI 0.67 to 1.04); HF-related mortality had a HR of 0.84 (95% CI 0.49 to 1.46); all-cause hospitalisation had a HR of 0.90 (95% CI 0.76 to 1.06); and HF-related hospitalisation had a HR of 0.98 (95% CI 0.72 to 1.35). There was a statistically significant difference in favour of ExCR for exercise capacity and HRQoL. Compared with the control, improvements were seen in the 6-minute walk test (6MWT) (mean 21.0 m, 95% CI 1.57 to 40.4 m) and Minnesota Living with Heart Failure Questionnaire score (mean -5.94, 95% CI -1.0 to -10.9; lower scores indicate improved HRQoL) at 12 months' follow-up. No strong evidence for differential intervention effects across patient characteristics was found for any outcomes. Moderate to good levels of correlation (R ² _trial > 50% and p > 0.50) between peak oxygen uptake (VO₂peak) or the 6MWT with mortality and HRQoL were seen. The estimated surrogate threshold effect was an increase of 1.6 to 4.6 ml/kg/minute for VO₂peak.

LIMITATIONS

There was a lack of consistency in how included RCTs defined and collected the outcomes: it was not possible to obtain IPD from all includable trials for all outcomes and patient-level data on exercise adherence was not sought.

CONCLUSIONS

In comparison with the no-exercise control, participation in ExCR improved the exercise and HRQoL in HF patients, but appeared to have no effect on their mortality or hospitalisation. No strong evidence was found of differential intervention effects of ExCR across patient characteristics. VO₂peak and 6MWT may be suitable surrogate end points for the treatment effect of ExCR on mortality and HRQoL in HF. Future studies should aim to achieve a consensus on the definition of outcomes and promote reporting of a core set of HF data. The research team also seeks to extend current policies to encourage study authors to allow access to RCT data for the purpose of meta-analysis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014007170.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Improving exercise capacity and quality of life using non-invasive heart failure treatments: evidence from clinical trials

Endpoints of large-scale trials in chronic heart failure have mostly been defined to evaluate treatments with regard to hospitalizations and mortality. However, patients with heart failure are also affected by very severe reductions in exercise capacity and quality of life. We aimed to evaluate the effects of heart failure treatments on these endpoints using available evidence from randomized trials. Interventions with evidence for improvements in exercise capacity include physical exercise, intravenous iron supplementation in patients with iron deficiency, and - with less certainty - testosterone in highly selected patients. Erythropoiesis-stimulating agents have been reported to improve exercise capacity in anaemic patients with heart failure. Sinus rhythm may have some advantage when compared with atrial fibrillation, particularly in patients undergoing pulmonary vein isolation. Studies assessing treatments for heart failure co-morbidities such as sleep-disordered breathing, diabetes mellitus, chronic kidney disease and depression have reported improvements of exercise capacity and quality of life; however, the available data are limited and not always consistent. The available evidence for positive effects of pharmacologic interventions using angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, beta-blockers, and mineralocorticoid receptor antagonists on exercise capacity and quality of life is limited. Studies with ivabradine and with sacubitril/valsartan suggest beneficial effects at improving quality of life; however, the evidence base is limited in particular for exercise capacity. The data for heart failure with preserved ejection fraction are even less positive, only sacubitril/valsartan and spironolactone have shown some effectiveness at improving quality of life. In conclusion, the evidence for state-of-the-art heart failure treatments with regard to exercise capacity and quality of life is limited and appears not robust enough to permit recommendations for heart failure. The treatment of co-morbidities may be important for these patient-related outcomes. Additional studies on functional capacity and quality of life in heart failure are required.

Impaired Exercise Tolerance in Heart Failure: Role of Skeletal Muscle Morphology and Function

PURPOSE OF REVIEW

To discuss the impact of deleterious changes in skeletal muscle morphology and function on exercise intolerance in patients with heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF), as well as the utility of exercise training and the potential of novel treatment strategies to preserve or improve skeletal muscle morphology and function.

RECENT FINDINGS

Both HFrEF and HFpEF patients exhibit a reduction in percent of type I (oxidative) muscle fibers and oxidative enzymes coupled with abnormal mitochondrial respiration. These skeletal muscle abnormalities contribute to impaired oxidative metabolism with an earlier shift towards glycolytic metabolism during exercise that is strongly associated with exercise intolerance. In both HFrEF and HFpEF patients, peripheral "non-cardiac" factors are important determinants of the improvement in exercise tolerance following aerobic exercise training. Adjunctive strategies that include nutritional supplementation with amino acids and/or anabolic drugs to stimulate anabolic molecular pathways in skeletal muscle show great promise for improving exercise tolerance and treating heart failure-associated sarcopenia, but these efforts remain early in their evolution, with no immediate clinical applications. There is consistent evidence that heart failure is associated with multiple skeletal muscle abnormalities which impair oxygen uptake and utilization and contribute greatly to exercise intolerance. Exercise training induces favorable adaptations in skeletal muscle morphology and function that contribute to improvements in exercise tolerance in patients with HFrEF. The contribution of skeletal muscle adaptations to improved exercise tolerance following exercise training in HFpEF remains unknown and warrants further investigation.

Impact of exercise-based cardiac rehabilitation in patients with heart failure (ExTraMATCH II) on mortality and hospitalisation: an individual patient data meta-analysis of randomised trials

AIMS

To undertake an individual patient data (IPD) meta-analysis to assess the impact of exercise-based cardiac rehabilitation (ExCR) in patients with heart failure (HF) on mortality and hospitalisation, and differential effects of ExCR according to patient characteristics: age, sex, ethnicity, New York Heart Association functional class, ischaemic aetiology, ejection fraction, and exercise capacity.

METHODS AND RESULTS

Randomised trials of exercise training for at least 3 weeks compared with no exercise control with 6-month follow-up or longer, providing IPD time to event on mortality or hospitalisation (all-cause or HF-specific). IPD were combined into a single dataset. We used Cox proportional hazards models to investigate the effect of ExCR and the interactions between ExCR and participant characteristics. We used both two-stage random effects and one-stage fixed effect models. IPD were obtained from 18 trials including 3912 patients with HF with reduced ejection fraction. Compared to control, there was no statistically significant difference in pooled time to event estimates in favour of ExCR although confidence intervals (CIs) were wide [all-cause mortality: hazard ratio (HR) 0.83, 95% CI 0.67-1.04; HF-specific mortality: HR 0.84, 95% CI 0.49-1.46; all-cause hospitalisation: HR 0.90, 95% CI 0.76-1.06; and HF-specific hospitalisation: HR 0.98, 95% CI 0.72-1.35]. No strong evidence was found of differential intervention effects across patient characteristics.

CONCLUSION

Exercise-based cardiac rehabilitation did not have a significant effect on the risk of mortality and hospitalisation in HF with reduced ejection fraction. However, uncertainty around effect estimates precludes drawing definitive conclusions.

Skeletal Muscle Myopathy in Heart Failure: the Role of Ejection Fraction

PURPOSE OF REVIEW

This review summarizes: (1) the structural and functional features coupled with pathophysiological factors responsible of skeletal muscle myopathy (SMM) in both heart failure with reduced (HFrEF) and preserved (HFpEF) ejection fraction and (2) the role of exercise as treatment of SMM in these HF-related phenotypes.

RECENT FINDINGS

The recent literature showed two main phenotypes of heart failure (HF): (1) HFrEF primarily due to a systolic dysfunction of the left ventricle and (2) HFpEF, mainly related to a diastolic dysfunction. Exercise intolerance is one of most disabling symptoms of HF and it is shown that persists after the normalization of the central hemodynamic impairments by therapy and/or cardiac surgery including heart transplant. A specific skeletal muscle myopathy (SMM) has been defined as one of the main causes of exercise intolerance in HF. The SMM has been well described in the last 20 years in the HFrEF; on the contrary, few studies are available in HFpEF. Recent evidences have revealed that exercise training counteracts HF-related SMM and in turn ameliorates exercise intolerance.

Meta-analysis of Exercise Training on Left Ventricular Ejection Fraction in Heart Failure with Reduced Ejection Fraction: A 10-year Update

BACKGROUND

The role of exercise training modality to attenuate left ventricular (LV) remodeling in heart failure patients with reduced ejection fraction (HFrEF) remains uncertain. The authors performed a systematic review and meta-analysis of published reports on exercise training (moderate-intensity continuous aerobic, high-intensity interval aerobic, and resistance exercise) and LV remodeling in clinically stable HFrEF patients.

METHODS

We searched MEDLINE, Cochrane Central Registry of Controlled Trials, CINAHL, and PubMed (2007 to 2017) for randomized controlled trials of exercise training on resting LV ejection fraction (EF) and end-diastolic and end-systolic volumes in HFrEF patients.

RESULTS

18 trials reported LV ejection fraction (LVEF) data, while 8 and 7 trials reported LV end-diastolic and LV end-systolic volumes, respectively. Overall, moderate-intensity continuous training (MICT) significantly increased LVEF (weighted mean difference, WMD = 3.79%; 95% confidence interval, CI, 2.08 to 5.50%) with no change in LV volumes versus control. In trials ≥6 months duration, MICT significantly improved LVEF (WMD = 6.26%; 95% CI 4.39 to 8.13%) while shorter duration (<6 months) trials modestly increased LVEF (WMD = 2.33%; 95% CI 0.84 to 3.82%). High-intensity interval training (HIIT) significantly increased LVEF compared to control (WMD = 3.70%; 95% CI 1.63 to 5.77%) but was not different than MICT (WMD = 3.17%; 95% CI -0.87 to 7.22%). Resistance training performed alone or combined with aerobic training (MICT or HIIT) did not significantly change LVEF.

CONCLUSIONS

In clinically stable HFrEF patients, MICT is an effective therapy to attenuate LV remodeling with the greatest benefits occurring with long-term (≥6 months) training. HIIT performed for 2 to 3 months is superior to control, but not MICT, for improvement of LVEF.

Effects of exercise modalities on central hemodynamics, arterial stiffness and cardiac function in cardiovascular disease: Systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Exercise is accepted as an important contribution to the rehabilitation of patients with cardiovascular disease (CVD). This study aims to better understand the possible causes for lack of consensus and reviews the effects of three exercise modalities (aerobic, resistance and combined exercise) on central hemodynamics, arterial stiffness and cardiac function for better rehabilitation strategies in CVD.

METHODS

The electronic data sources, Cochrane Library, MEDLINE, Web of Science, EBSCO (CINAHL), and ScienceDirect from inception to July 2017 were searched for randomized controlled trials (RCTs) investigating the effect of exercise modalities in adult patients with CVD. The effect size was estimated as mean differences (MD) with 95% confidence intervals (CI). Subgroup analysis and meta-regression were used to study potential moderating factors.

RESULTS

Thirty-eight articles describing RCTs with a total of 2089 patients with CVD were included. The pooling revealed that aerobic exercise [MD(95%CI) = -5.87 (-8.85, -2.88), P = 0.0001] and resistance exercise [MD(95%CI) = -7.62 (-10.69, -4.54), P<0.00001] significantly decreased aortic systolic pressure (ASP). Resistance exercise significantly decreased aortic diastolic pressure [MD(95%CI) = -4(-5.63, -2.37), P<0.00001]. Aerobic exercise significantly decreased augmentation index (AIx) based on 24-week exercise duration and patients aged 50-60 years. Meanwhile, aerobic exercise significantly improved carotid-femoral pulse wave velocity (cf-PWV) [MD(95%CI) = -0.42 (-0.83, -0.01), P = 0.04], cardiac output (CO) [MD(95% CI) = 0.36(0.08, 0.64), P = 0.01] and left ventricular ejection fraction (LVEF) [MD(95%CI) = 3.02 (2.11, 3.93), P<0.00001]. Combined exercise significantly improved cf-PWV [MD(95%CI) = -1.15 (-1.95, -0.36), P = 0.004] and CO [MD(95% CI) = 0.9 (0.39, 1.41), P = 0.0006].

CONCLUSIONS

Aerobic and resistance exercise significantly decreased ASP, and long-term aerobic exercise reduced AIx. Meanwhile, aerobic and combined exercise significantly improved central arterial stiffness and cardiac function in patients with CVD. These findings suggest that a well-planned regime could optimize the beneficial effects of exercise and can provide some evidence-based guidance for those involved in cardiovascular rehabilitation of patients with CVD.

Myocardial strain may predict exercise tolerance in patients with reduced and mid-range ejection fraction

BACKGROUND

Conventional echocardiographic parameters, such as rest ejection fraction, perform poorly in the prediction of exercise tolerance in heart failure. The aim of the present study was to evaluate the contribution of hemodynamic instability in the observed lower functional capacity and investigate the role of left ventricular strain for the prediction of stress test duration in obese hypertensive patients with reduced ejection fraction.

METHODS

Sixty-one patients with reduced ejection fraction underwent treadmill exercise echocardiography. Systolic and diastolic echocardiographic parameters were recorded. Moreover, the presence of hemodynamic instability was assessed through N-terminal pro B-type natriuretic peptide (NT-proBNP) measurements at baseline and peak exercise.

RESULTS

Rest and peak NT-proBNP levels, and their difference, were significantly correlated with mean global strain at peak, which was the only parameter associated with changes in NT-proBNP levels. Rest and peak mean global strain were found to be predictive for the duration of treadmill stress test. In particular, mean global strain, but not left ventricular ejection fraction, was independently correlated with exercise ability.

CONCLUSIONS

Stress echocardiography may provide important information regarding exercise tolerance in obese hypertensive patients with reduced ejection fraction, mainly through the evaluation of left ventricular strain. The obtained evidence may also have prognostic value, particularly in the early stages of the syndrome.

Physical function and exercise training in older patients with heart failure

Heart failure (HF) is a common end point for numerous cardiovascular conditions, including coronary artery disease, valvular disease, and hypertension. HF predominantly affects older individuals (aged ≥70 years), particularly those living in developed countries. The pathophysiological sequelae of HF progression have a substantial negative effect on physical function. Diminished physical function in older patients with HF, which is the result of combined disease-related and age-related effects, has important implications on health. A large body of research spanning several decades has demonstrated the safety and efficacy of regular physical activity in improving outcomes among the HF population, regardless of age, sex, or ethnicity. However, patients with HF, especially those who are older, are less likely to engage in regular exercise training compared with the general population. To improve initiation of regular exercise training and subsequent long-term compliance, there is a need to rethink the dialogue between clinicians and patients. This Review discusses the need to improve physical function and exercise habits in patients with HF, focusing on the older population.

Mechanisms of the Improvement in Peak VO2 With Exercise Training in Heart Failure With Reduced or Preserved Ejection Fraction

Heart failure (HF) is a major health care burden associated with high morbidity and mortality. Approximately 50% of HF patients have reduced ejection fraction (HFrEF) while the remainder of patients have preserved ejection fraction (HFpEF). A hallmark of both HF phenotypes is dyspnoea upon exertion and severe exercise intolerance secondary to impaired oxygen delivery and/or use by exercising skeletal muscle. Exercise training is a safe and effective intervention to improve peak oxygen uptake (VO_2peak) and quality of life in clinically stable HF patients, however, evidence to date suggests that the mechanism of this improvement appears to be related to underlying HF phenotype. The purpose of this review is to discuss the role of exercise training to improve VO_2peak, and how the central and peripheral adaptations that mediate the improvements in exercise tolerance may be similar or differ by HF phenotype (HFrEF or HFpEF).

Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases

This review provides the reader with the up-to-date evidence-based basis for prescribing exercise as medicine in the treatment of 26 different diseases: psychiatric diseases (depression, anxiety, stress, schizophrenia); neurological diseases (dementia, Parkinson's disease, multiple sclerosis); metabolic diseases (obesity, hyperlipidemia, metabolic syndrome, polycystic ovarian syndrome, type 2 diabetes, type 1 diabetes); cardiovascular diseases (hypertension, coronary heart disease, heart failure, cerebral apoplexy, and claudication intermittent); pulmonary diseases (chronic obstructive pulmonary disease, asthma, cystic fibrosis); musculo-skeletal disorders (osteoarthritis, osteoporosis, back pain, rheumatoid arthritis); and cancer. The effect of exercise therapy on disease pathogenesis and symptoms are given and the possible mechanisms of action are discussed. We have interpreted the scientific literature and for each disease, we provide the reader with our best advice regarding the optimal type and dose for prescription of exercise.

The effect of endurance training on exercise capacity following cardiac resynchronization therapy in chronic heart failure patients: a pilot trial

BACKGROUND

Both endurance training (ET) and cardiac resynchronization therapy (CRT) improve quality of life (QOL) and exercise tolerance in patients with advanced chronic heart failure (CHF).

DESIGN

A randomized intervention trial to study the effect on exercise capacity of ET in addition to CRT in patients with CHF and dyssynchrony.

METHODS

Seventeen patients (eight men, aged 59+/-9 years) with CHF and dyssynchrony were randomized to CRT with (n=8) or without (n=9) ET and compared with two matched control CHF groups (standard care with ET: n=9, standard care only: n=10). At baseline and after 5 months, exercise tolerance, left ventricular (LV) remodelling, QOL and NT-pro brain natriuretic peptide (NT-proBNP) levels were assessed.

RESULTS

Peak oxygen consumption (VO2peak), maximal workload (Wattmax), circulatory power, LV ejection fraction, dyssynchrony and QOL improved in both CRT groups. However, the increase in VO2peak (+40% versus +16%, P=0.005), Wattmax (+43% versus +13%, P=0.0005), and circulatory power (+74% versus +32%, P=0.01), was significantly greater in the trained versus the untrained CRT patients. Comparison of the four patient groups confirmed the cumulative effects of CRT plus ET.

CONCLUSIONS

ET in resynchronized CHF patients is feasible and further enhances exercise tolerance. Patients with severe CHF should be prescribed an exercise training programme after implantation in order to maximize the expected benefit.

Alternatives to Aerobic Exercise Prescription in Patients with Chronic Heart Failure

Background

Exercise is essential for patients with heart failure as it leads to a reduction in morbidity and mortality as well as improved functional capacity and oxygen uptake (⩒O₂). However, the need for an experienced physiologist and the cost of the exam may render the cardiopulmonary exercise test (CPET) unfeasible. Thus, the six-minute walk test (6MWT) and step test (ST) may be alternatives for exercise prescription.

Objective

The aim was to correlate heart rate (HR) during the 6MWT and ST with HR at the anaerobic threshold (HR_AT) and peak HR (HR_P) obtained on the CPET.

Methods

Eighty-three patients (58 ± 11 years) with heart failure (NYHA class II) were included and all subjects had optimized medication for at least 3 months. Evaluations involved CPET (⩒O₂, HR_AT, HR_P), 6MWT (HR_6MWT) and ST (HR_ST).

Results

The participants exhibited severe ventricular dysfunction (ejection fraction: 31 ± 7%) and low peak ⩒O2 (15.2 ± 3.1 mL.kg_-1.min_-1). HR_P (113 ± 19 bpm) was higher than HR_AT (92 ± 14 bpm; p < 0.05) and HR_6MWT (94 ± 13 bpm; p < 0.05). No significant difference was found between HR_P and HR_ST. Moreover, a strong correlation was found between HR_AT and HR_6MWT (r = 0.81; p < 0.0001), and between HR_P and HR_ST (r = 0.89; p < 0.0001).

Conclusion

These findings suggest that, in the absence of CPET, exercise prescription can be performed by use of 6MWT and ST, based on HR_6MWT and HR_ST

Aerobic training enhances muscle deoxygenation in early post-myocardial infarction

Purpose

Exercise-induced skeletal muscle deoxygenation is startling by its absence in early post-myocardial infarction (MI) patients. Exercise training early post-MI is associated with reduced cardiovascular risk and increased aerobic capacity. We therefore investigated whether aerobic training could enhance the muscle deoxygenation in early post-MI patients.

Methods

21 ± 8 days after the first MI patients (n = 16) were divided into 12-week aerobic training (TR, n = 10) or non-training (CON, n = 6) groups. Before and after intervention, patients performed ramp bicycle exercise until exhaustion. Muscle deoxygenation was measured at vastus lateralis by near-infrared spectroscopy during exercise.

Results

Aerobic training significantly increased peak oxygen uptake (VO₂) (18.1 ± 3.0 vs. 22.9 ± 2.8 mL/kg/min), decreased the change in muscle oxygen saturation from rest to submaximal and peak exercise (∆SmO₂; 2.4 ± 5.7 vs. −7.0 ± 3.4 %), and increased the relative change in deoxygenated hemoglobin/myoglobin concentration from rest to submaximal (−1.5 ± 2.3 vs. 3.0 ± 3.6 μmol/L) and peak exercise (1.1 ± 4.5 vs. 8.2 ± 3.5 μmol/L). Change in total hemoglobin/myoglobin concentration in muscle was not significantly affected by training. In CON, no significant alterations were found after 12 weeks in either muscle deoxygenation or peak VO₂ (18.6 ± 3.8 vs. 18.9 ± 4.6 mL/kg/min). An increase in peak VO₂ was significantly negatively correlated with change in ∆SmO₂ (r = −0.65) and positively associated with change in ∆deoxy-Hb/Mb at peak exercise (r = 0.64) in TR.

Conclusions

In early post-MI patients, aerobic training enhanced skeletal muscle deoxygenation, and the enhancement was related to increased aerobic capacity.

Possible neurocognitive benefits of exercise in persons with heart failure

More than 6 million Americans have heart failure (HF) and more than 500,000 are diagnosed each year. In addition to its many adverse medical consequences, HF is also a significant risk factor for neurological disorders like Alzheimer's disease and associated with cognitive impairment long prior to the onset of these conditions. Converging bodies of literature suggest cognitive dysfunction in HF may be at least partially modifiable. One key mechanism for cognitive improvement is improved cerebral blood flow, which may be possible with exercise in patients with HF. This brief review provides a model for the likely neurocognitive benefits of exercise in HF and encourages further work in this area.

Impact of training methods and patient characteristics on exercise capacity in patients in cardiovascular rehabilitation

AIM

We aimed to identify patient characteristics and comorbidities that correlate with the initial exercise capacity of cardiac rehabilitation (CR) patients and to study the significance of patient characteristics, comorbidities and training methods for training achievements and final fitness of CR patients.

METHODS

We studied 557 consecutive patients (51.7 ± 6.9 years; 87.9% men) admitted to a three-week in-patient CR. Cardiopulmonary exercise testing (CPX) was performed at discharge. Exercise capacity (watts) at entry, gain in training volume and final physical fitness (assessed by peak O2 utilization (VO2peak) were analysed using analysis of covariance (ANCOVA) models.

RESULTS

Mean training intensity was 90.7 ± 9.7% of maximum heart rate (81% continuous/19% interval training, 64% additional strength training). A total of 12.2 ± 2.6 bicycle exercise training sessions were performed. Increase of training volume by an average of more than 100% was achieved (difference end/beginning of CR: 784 ± 623 watts × min). In the multivariate model the gain in training volume was significantly associated with smoking, age and exercise capacity at entry of CR. The physical fitness level achieved at discharge from CR as assessed by VO2peak was mainly dependent on age, but also on various factors related to training, namely exercise capacity at entry, increase of training volume and training method.

CONCLUSION

CR patients were trained in line with current guidelines with moderate-to-high intensity and reached a considerable increase of their training volume. The physical fitness level achieved at discharge from CR depended on various factors associated with training, which supports the recommendation that CR should be offered to all cardiac patients.

Clinical utility of exercise training in heart failure with reduced and preserved ejection fraction

Reduced exercise tolerance is an independent predictor of hospital readmission and mortality in patients with heart failure (HF). Exercise training for HF patients is well established as an adjunct therapy, and there is sufficient evidence to support the favorable role of exercise training programs for HF patients over and above the optimal medical therapy. Some of the documented benefits include improved functional capacity, quality of life (QoL), fatigue, and dyspnea. Major trials to assess exercise training in HF have, however, focused on heart failure with reduced ejection fraction (HFREF). At least half of the patients presenting with HF have heart failure with preserved ejection fraction (HFPEF) and experience similar symptoms of exercise intolerance, dyspnea, and early fatigue, and similar mortality risk and rehospitalization rates. The role of exercise training in the management of HFPEF remains less clear. This article provides a brief overview of pathophysiology of reduced exercise tolerance in HFREF and heart failure with preserved ejection fraction (HFPEF), and summarizes the evidence and mechanisms by which exercise training can improve symptoms and HF. Clinical and practical aspects of exercise training prescription are also discussed.

[Effects of long-term exercise training on left ventricular function and remodeling in patients with anterior wall myocardial infarction]

OBJECTIVE

To assess the effects of long-term exercise training on the function and remodeling of the left ventricle after myocardial infarction.

METHODS

We studied 90 patients with a first acute anterior-wall myocardial infarction, all received conventional medical treatment. Symptom-limited maximal exercise stress tests, echocardiograms and effort-rest isotopic ventriculographies at 2, 6 and 12 months after myocardial infarction were performed; the follow-up time averaged 36.3±17 months. All patients joined a cardiac rehabilitation program with moderate or intense exercise training lasting at least a year. Of all patients, 41.1% suffered severe left ventricle dysfunction.

RESULTS

Ergometric parameters that expressed functional capacity increased significantly (P<.0005) at the sixth month evaluation and remained unchanged after a year. There was significant decrease (P<.01) of exercise myocardial ischemia at 6 months. The variables that measured size and function of left ventricle did not change during evolution. Morbidity amounted to 16.7% and total mortality of the series was 13.3%, with 8.9% of cardiovascular cause.

CONCLUSIONS

Long-term exercise training showed no deleterious effects on left ventricle function or remodeling and beneficial functional and clinical effects were obtained in these rehabilitated postinfarction patients.

Assessment of cardiac output with transpulmonary thermodilution during exercise in humans

The accuracy and reproducibility of transpulmonary thermodilution (TPTd) to assess cardiac output (Q̇) in exercising men was determined using indocyanine green (ICG) dilution as a reference method. TPTd has been utilized for the assessment of Q̇ and preload indexes of global end-diastolic volume and intrathoracic blood volume, as well as extravascular lung water (EVLW) in resting humans. It remains unknown if this technique is also accurate and reproducible during exercise. Sixteen healthy men underwent catheterization of the right femoral vein (for iced saline injection), an antecubital vein (ICG injection), and femoral artery (thermistor) to determine their Q̇ by TPTd and ICG concentration during incremental one- and two-legged pedaling on a cycle ergometer and combined arm cranking with leg pedaling to exhaustion. There was a close relationship between TPTd-Q̇ and ICG-Q̇ ( r = 0.95, n = 151, standard error of the estimate: 1.452 l/min, P < 0.001; mean difference of 0.06 l/min; limits of agreement −2.98 to 2.86 l/min), and TPTd-Q̇ and ICG-Q̇ increased linearly with oxygen uptake with similar intercepts and slopes. Both methods had mean coefficients of variation close to 5% for Q̇, global end-diastolic volume, and intrathoracic blood volume. The mean coefficient of variation of EVLW, assessed with both indicators (ICG and thermal) was 17% and was sensitive enough to detect a reduction in EVLW of 107 ml when changing from resting supine to upright exercise. In summary, TPTd with bolus injection into the femoral vein is an accurate and reproducible method to assess Q̇ during exercise in humans.

Left ventricular global longitudinal strain is associated with exercise capacity in failing hearts with preserved and reduced ejection fraction

Aims

Heart failure patients with reduced and preserved left ventricular (LV) ejection fraction (EF) show reduced exercise capacity. We explored the relationship between exercise capacity and systolic and diastolic myocardial function in heart failure patients.

Methods and results

Exercise capacity, by peak oxygen uptake (VO₂), was assessed in 100 patients (56 ± 12 years, NYHA functional class: 2.5 ± 0.9, EF: 42 ± 19%). LV systolic function, as EF and global longitudinal strain (GLS), and right ventricular function were assessed by echocardiography. Left atrial volume index and the ratio of peak early diastolic filling velocity (E) to early diastolic mitral annular velocity (e′) were measures of diastolic function. Thirty-seven patients had heart failure with preserved EF (HFpEF), defined as EF ≥50% and echocardiographic diastolic dysfunction. LV GLS and peak pulmonary arterial systolic pressure were independently correlated to peak VO₂ in the total study population and in HFpEF separately. LV GLS was superior to EF in identifying patients with impaired peak VO₂ <20 mL/kg/min as shown by receiver operating characteristic analyses [areas under curves 0.93 (0.89–0.98) vs. 0.85 (0.77–0.93), P < 0.05]. In patients with HFpEF, GLS was reduced below normal (−17.5 ± 3.2%) and correlated to E/e′ (R = 0.45, P = 0.005) and left atrial volume index (R = 0.48, P = 0.003), while EF did not.

Conclusion

GLS correlated independently to peak VO₂ in patients with reduced and preserved EF and was superior in identifying patients with reduced exercise capacity. In HFpEF, systolic function by GLS was impaired. There was a significant relationship between diastolic function and GLS, confirming a coupling between diastolic and longitudinal systolic function in HFpEF.

Effects of exercise on cardiovascular performance in the elderly

Progressive aging induces several structural and functional alterations in the cardiovascular system, among whom particularly important are a reduced number of myocardial cells and increased interstitial collagen fibers, which result in impaired left ventricular diastolic function. Even in the absence of cardiovascular disease, aging is strongly associated to a age-related reduced maximal aerobic capacity. This is due to a variety of physiological changes both at central and at peripheral level. Physical activity (PA) appears in general to have a positive effect on several health outcomes in the elderly. This review aims to illustrate the beneficial effects of exercise on the physiologic decline of cardiovascular performance occurring with age. Furthermore, it will be stressed also the positive effect of physical activity in elderly patients affected by cardiovascular diseases, such as heart failure and hypertension, and multiple comorbidities which may significantly worse prognosis in this high risk population.

Exercise-resembling effects of periodic somatosensory stimulation in heart failure

BACKGROUND

The mechanism of the beneficial effects of exercise training on autonomic derangement and neurohumoral activation in chronic heart failure (CHF) is largely unexplained. In our here-presented hypothesis-generating study we propose that part of these effects is mediated by the exercise-accompanying somatosensory nerve traffic. To demonstrate this, we compared the effects of periodic electrical somatosensory stimulation in patients with CHF with the effects of exercise training and with usual care.

METHODS

In a randomized controlled study we measured, in CHF patients, changes in blood pressure, baroreflex sensitivity (BRS), neurohormones, exercise capacity and quality of life (QOL) in response to periodic somatosensory stimulation in the form of 2 Hz transcutaneous electrical nerve stimulation (TENS) at both feet, in response to conventional exercise training (EXTR) and, as control (CTRL), in patients with usual care only.

RESULTS

Group sizes were N=31 (TENS group), N=25 (EXTR group) and N=30 (CTRL group), respectively. Practically all improvements in BRS, neurohormone concentrations, exercise capacity and QOL in the TENS group were comparable to, or sometimes even better than in the EXTR group. These improvements were not observed in the CTRL group.

CONCLUSIONS

This study demonstrates that periodic electrical somatosensory stimulation is as effective as exercise training in improving BRS, neurohormone concentrations, exercise capacity and QOL in CHF patients. These results encourage exploration of exercise modalities that concentrate on rhythm rather than on effort, with the purpose to normalize autonomic derangement and neurohumoral activation in CHF.

Exercise training in chronic heart failure

The syndrome of heart failure (HF) is a growing epidemic that causes a significant socio-economic burden. Despite considerable progress in the management of patients with HF, mortality and morbidity remain a major healthcare concern and frequent hospital admissions jeopardize daily life and social activities. Exercise training is an important adjunct nonpharmacological treatment modality for patients with HF that has proven positive effects on mortality, morbidity, exercise capacity and quality of life. Different training modalities are available to target the problems with which HF patients are faced. It is essential to tailor the prescribed exercise regimen, so that both efficiency and safety are guaranteed. Electrical implanted devices and mechanical support should not exclude patients from exercise training; however, particular precautions and a specialized approach are advised. At least 50% of patients with HF, older than 65 years of age, present with HF with preserved ejection fraction (HFPEF). Although the study populations included in studies evaluating the effect of exercise training in this population are small, the results are promising and seem to support the idea that exercise training is beneficial for HFPEF patients. Both the short- and especially long-term adherence to exercise training remain a major challenge that can only be tackled by a multidisciplinary approach. Efforts should be directed towards closing the gap between recommendations and the actual implementation of training programmes.

Aerobic exercise intensity assessment and prescription in cardiac rehabilitation: a joint position statement of the European Association for Cardiovascular Prevention and Rehabilitation, the American Association of Cardiovascular and Pulmonary Rehabilitation, and the Canadian Association of Cardiac Rehabilitation

Aerobic exercise intensity prescription is a key issue in cardiac rehabilitation, being directly linked to both the amount of improvement in exercise capacity and the risk of adverse events during exercise. This joint position statement aims to provide professionals with up-to-date information regarding the identification of different exercise intensity domains, the methods of direct and indirect determination of exercise intensity for both continuous and interval aerobic training, the effects of the use of different exercise protocols on exercise intensity prescription and the indications for recommended exercise training prescription in specific cardiac patients' groups. The importance of functional evaluation through exercise testing prior to starting an aerobic training program is strongly emphasized, and ramp incremental cardiopulmonary exercise test, when available, is proposed as the gold standard for a physiologically comprehensive exercise intensity assessment and prescription. This may allow a shift from a 'range-based' to a 'threshold-based' aerobic exercise intensity prescription, which, combined with thorough clinical evaluation and exercise-related risk assessment, could maximize the benefits obtainable by the use of aerobic exercise training in cardiac rehabilitation.

Intrinsic skeletal muscle alterations in chronic heart failure patients: a disease-specific myopathy or a result of deconditioning?

Chronic heart failure (CHF) patients frequently experience impaired exercise tolerance due to skeletal muscle fatigue. Studies suggest that this in part is due to intrinsic alterations in skeletal muscle of CHF patients, often interpreted as a disease-specific myopathy. Knowledge about the mechanisms underlying these skeletal muscle alterations is of importance for the pathophysiological understanding of CHF, therapeutic approach and rehabilitation strategies. We here critically review the evidence for skeletal muscle alterations in CHF, the underlying mechanisms of such alterations and how skeletal muscle responds to training in this patient group. Skeletal muscle characteristics in CHF patients are very similar to what is reported in response to chronic obstructive pulmonary disease (COPD), detraining and deconditioning. Furthermore, skeletal muscle alterations observed in CHF patients are reversible by training, and skeletal muscle of CHF patients seems to be at least as trainable as that of matched controls. We argue that deconditioning is a major contributor to the skeletal muscle dysfunction in CHF patients and that further research is needed to determine whether, and to what extent, the intrinsic skeletal muscle alterations in CHF represent an integral part of the pathophysiology in this disease.

Testosterone therapy during exercise rehabilitation in male patients with chronic heart failure who have low testosterone status: a double-blind randomized controlled feasibility study

BACKGROUND

This study assessed the feasibility of a 12-week program of exercise, with and without intramuscular testosterone supplementation, in male patients with chronic heart failure (CHF) and low testosterone status and collected preliminary data for key health outcomes.

METHODS

Male patients with CHF (n = 41, age 67.2 years, range 51-84 years) with mean ± SD testosterone levels of 10.7 ± 2.6 nmol/L (309 ± 76 ng/dL) were randomly allocated to exercise with testosterone or placebo groups. Feasibility was assessed in terms of recruitment, intervention compliance, and attrition. Outcomes included an incremental shuttle walk test, peak oxygen uptake, muscular strength, echocardiographic measures, N-terminal pro-brain natriuretic peptide, inflammatory markers, depression (Beck Depression Inventory), and health-related quality of life (Minnesota Living with Heart Failure Questionnaire and Medical Outcomes Study Short-Form).

RESULTS

Attrition was 30% but with 100% compliance to exercise and injections in patients who completed the study. Similar improvements in shuttle walk test (18% vs 19%), body mass (-1.3 kg vs -1.0 kg), and hand grip strength (2.1 kg vs 2.5 kg) from baseline were observed in both groups. The exercise with testosterone group showed improvements from baseline in peak oxygen uptake (P < .01), Beck Depression Inventory (P < .05), leg strength (P < .05), and several Medical Outcomes Study Short-Form quality of life domains (P < .05), which were generally not apparent in the exercise with placebo group. Echocardiographic measures, N-terminal pro-brain natriuretic peptide, and inflammatory markers were mostly unchanged.

CONCLUSIONS

This study shows for the first time that testosterone supplementation during a program of exercise rehabilitation is feasible and can positively impact on a range of key health outcomes in elderly male patients with CHF who have a low testosterone status.

Aerobic exercise intensity assessment and prescription in cardiac rehabilitation: a joint position statement of the European Association for Cardiovascular Prevention and Rehabilitation, the American Association of Cardiovascular and Pulmonary Rehabilitation and the Canadian Association of Cardiac Rehabilitation

Aerobic exercise intensity prescription is a key issue in cardiac rehabilitation, being directly linked to both the amount of improvement in exercise capacity and the risk of adverse events during exercise. This joint position statement aims to provide professionals with up-to-date information regarding the identification of different exercise intensity domains, the methods of direct and indirect determination of exercise intensity for both continuous and interval aerobic training, the effects of the use of different exercise protocols on exercise intensity prescription and the indications for recommended exercise training prescription in specific cardiac patients' groups. The importance of functional evaluation through exercise testing prior to starting an aerobic training program is strongly emphasized, and ramp incremental cardiopulmonary exercise test, when available, is proposed as the gold standard for a physiologically comprehensive exercise intensity assessment and prescription. This may allow a shift from a 'range-based' to a 'threshold-based' aerobic exercise intensity prescription, which, combined with thorough clinical evaluation and exercise-related risk assessment, could maximize the benefits obtainable by the use of aerobic exercise training in cardiac rehabilitation.

Effect of endurance training on the determinants of peak exercise oxygen consumption in elderly patients with stable compensated heart failure and preserved ejection fraction

OBJECTIVES

The purpose of this study was to evaluate the mechanisms for improved exercise capacity after endurance exercise training (ET) in elderly patients with heart failure and preserved ejection fraction (HFPEF).

BACKGROUND

Exercise intolerance, measured objectively by reduced peak oxygen consumption (VO(2)), is the primary chronic symptom in HFPEF and is improved by ET. However, the mechanisms are unknown.

METHODS

Forty stable, compensated HFPEF outpatients (mean age 69 ± 6 years) were examined at baseline and after 4 months of ET (n = 22) or attention control (n = 18). The VO(2) and its determinants were assessed during rest and peak upright cycle exercise.

RESULTS

After ET, peak VO(2) in those patients was higher than in control patients (16.3 ± 2.6 ml/kg/min vs. 13.1 ± 3.4 ml/kg/min; p = 0.002). That was associated with higher peak heart rate (139 ± 16 beats/min vs. 131 ± 20 beats/min; p = 0.03), but no difference in peak end-diastolic volume (77 ± 18 ml vs. 77 ± 17 ml; p = 0.51), stroke volume (48 ± 9 ml vs. 46 ± 9 ml; p = 0.83), or cardiac output (6.6 ± 1.3 l/min vs. 5.9 ± 1.5 l/min; p = 0.32). However, estimated peak arterial-venous oxygen difference was significantly higher in ET patients (19.8 ± 4.0 ml/dl vs. 17.3 ± 3.7 ml/dl; p = 0.03). The effect of ET on cardiac output was responsible for only 16% of the improvement in peak VO(2).

CONCLUSIONS

In elderly stable compensated HFPEF patients, peak arterial-venous oxygen difference was higher after ET and was the primary contributor to improved peak VO(2). This finding suggests that peripheral mechanisms (improved microvascular and/or skeletal muscle function) contribute to the improved exercise capacity after ET in HFPEF. (Prospective Aerobic Reconditioning Intervention Study [PARIS]; NCT01113840).

Central hemodynamic responses during acute high-intensity interval exercise and moderate continuous exercise in patients with heart failure

The aim of this study was to compare the acute hemodynamic responses during high-intensity intermittent exercise (HIIE) session compared with moderate-intensity continuous exercise (MICE) session in patients with heart failure and reduced ejection fraction (HFREF). Thirteen patients with HFREF (age, 59 ± 6 years; left ventricular ejection fraction, 27% ± 6%; New York Heart Association class I to III) were randomly assigned to a single session of HIIE (2 × 8 min) corresponding to 30 s at 100% of peak power output (PPO) and 30 s passive recovery intervals or to a MICE (22 min) at 60% of PPO. Gas exchange and central hemodynamic parameters (cardiac bioimpedance) were measured continuously during exercise. Oxygen uptake, stroke volume (SV), cardiac output (CO), and arterio-venous difference (C(a-v)O(2)) were compared. Mean oxygen uptake and ventilation were lower during HIIE vs. MICE. CO, SV, and C(a-v)O(2)) were not different between MICE and HIIE. Optimized HIIE was well tolerated (similar perceived exertion) and no significant ventricular arrhythmias and (or) abnormal blood pressure responses occurred during HIEE session. Compared with MICE, optimized HIIE elicited similar central hemodynamic and C(a-v)O(2) responses in HFREF patients with lower oxygen uptake and ventilation. HIIE may be an efficient exercise training modality in patients with HFREF.

Association between heart rate at rest and myocardial perfusion in patients with acute myocardial infarction undergoing cardiac rehabilitation - a pilot study

INTRODUCTION

This study was conducted to determine if there was a link among heart rate at rest (rHR), muscle volume changes, and single photon emission computed tomography (SPECT) parameters after 6-month cardiac rehabilitation in patients with acute myocardial infarction (AMI).

MATERIAL AND METHODS

Twenty-nine consecutive AMI patients (mean age: 63.0 ±9.1 years) who received appropriate percutaneous coronary intervention on admission were enrolled. (99m)Tc-Sestamibi myocardial SPECT images were obtained at the early (30 min) and delayed (4 h) phases after tracer injection at 2 weeks (0M) and 6 months (6M) after the onset of AMI. Within a few days of SPECT, all patients underwent cardiopulmonary exercise test for evaluation of cardiac rehabilitation effects. Before the initiation of exercise test, leg muscle volume was measured. All patients were stratified into the ≥ 70 beats per minute (bpm) (n = 15) or < 70 bpm (n = 14) group based on rHR at 6M.

RESULTS

There were no significant differences in the recanalization time, peak cardiac enzyme, or initial left ventricular ejection fraction between the two groups. After the 6-month training, the muscle volume changes in the lower limbs (< 70 bpm, 0.23 ±0.22; ≥ 70 bpm, -0.07 ±0.26, p < 0.05) were significantly greater in the < 70 bpm group than the ≥ 70 bpm group. The decreased rate of rHR had a significant correlation with the improved global severity (r = 0.62, p = 0.001) and extent (r = 0.48, p = 0.017) of left ventricle evaluated by (99m)Tc-Sestamibi myocardial SPECT delayed phase.

CONCLUSIONS

The result of this preliminary study demonstrated that improved myocardial perfusion was closely related to decreased rHR after cardiac rehabilitation.

Exercise performance comparison of bicaval and biatrial orthotopic heart transplant recipients

BACKGROUND

The standard biatrial technique for orthotopic heart transplantation uses a large atrial anastomosis to connect the donor and recipient atria. A modified technique involves bicaval and pulmonary venous anastomoses and is believed to preserve the anatomic configuration and physiological function of the atria. Bicaval heart transplantation reduces postoperative valvular regurgitation and is associated with a lower incidence of pacemaker insertion.

OBJECTIVE

The aim of this study was to compare postoperative functional capacity and exercise performance in patients with bicaval and biatrial orthotopic heart transplantation.

METHODS

Patients were selected for the study if they did not have any of the following: obstructive coronary artery disease (>50% stenosis), severe mitral or tricuspid regurgitation, signs of rejection (grade≥1B-1R) on endomyocardial biopsy during the prior year, respiratory impairment, a permanent pacemaker, orthopedic or muscular impediments, or lived more than 150 miles from the medical center. A total of 27 patients qualified. In 15 patients who received a biatrial heart transplant and 12 patients with a bicaval heart transplant, a stationary bicycle exercise test was performed. Ventilatory gas exchange and maximum oxygen consumption measurements were measured.

RESULTS

Recipient and donor characteristics, including body surface area, donor/recipient weight mismatch, immunosuppressive regimen, and self-reported weekly exercise activity, did not differ between the biatrial and bicaval groups (P=not significant [NS]). At peak exercise, similar heart rate, workload, oxygen consumption, carbon dioxide production, ventilation, functional capacity, and exercise duration were found between the 2 groups (P=NS). Patients in the biatrial group were studied later than patients in the bicaval group (6.54±0.71 vs 4.68±0.28 years; P<.001).

CONCLUSION

There were no significant differences in the exercise capacity between patients with biatrial versus bicaval techniques for orthotopic heart transplantation. Factors other than the atrial connection (such as cardiac denervation, immunosuppressive drug effect, or physical deconditioning) may be more important determinants of subnormal exercise capacity after heart transplantation. Nevertheless, the reduction in morbidity and postoperative complications and the simplicity in the bicaval technique suggest that bicaval heart transplantation offers advantages when compared with the standard biatrial technique.

Muscle oxygen transport and utilization in heart failure: implications for exercise (in)tolerance

The defining characteristic of chronic heart failure (CHF) is an exercise intolerance that is inextricably linked to structural and functional aberrations in the O(2) transport pathway. CHF reduces muscle O(2) supply while simultaneously increasing O(2) demands. CHF severity varies from moderate to severe and is assessed commonly in terms of the maximum O(2) uptake, which relates closely to patient morbidity and mortality in CHF and forms the basis for Weber and colleagues' (167) classifications of heart failure, speed of the O(2) uptake kinetics following exercise onset and during recovery, and the capacity to perform submaximal exercise. As the heart fails, cardiovascular regulation shifts from controlling cardiac output as a means for supplying the oxidative energetic needs of exercising skeletal muscle and other organs to preventing catastrophic swings in blood pressure. This shift is mediated by a complex array of events that include altered reflex and humoral control of the circulation, required to prevent the skeletal muscle "sleeping giant" from outstripping the pathologically limited cardiac output and secondarily impacts lung (and respiratory muscle), vascular, and locomotory muscle function. Recently, interest has also focused on the dysregulation of inflammatory mediators including tumor necrosis factor-α and interleukin-1β as well as reactive oxygen species as mediators of systemic and muscle dysfunction. This brief review focuses on skeletal muscle to address the mechanistic bases for the reduced maximum O(2) uptake, slowed O(2) uptake kinetics, and exercise intolerance in CHF. Experimental evidence in humans and animal models of CHF unveils the microvascular cause(s) and consequences of the O(2) supply (decreased)/O(2) demand (increased) imbalance emblematic of CHF. Therapeutic strategies to improve muscle microvascular and oxidative function (e.g., exercise training and anti-inflammatory, antioxidant strategies, in particular) and hence patient exercise tolerance and quality of life are presented within their appropriate context of the O(2) transport pathway.