Prognostic value and diagnostic potential of cardiopulmonary exercise testing in patients with chronic heart failure

Effect of Exercise-Based Cardiac Rehabilitation on Patients With Chronic Heart Failure After Transcatheter Aortic Valve Replacement: A Randomized Controlled Trial

PURPOSE

The objective of this study was to assess the effect of exercise-based cardiac rehabilitation (CR) with individualized exercise prescription in patients with chronic heart failure (HF) undergoing transcatheter aortic valve replacement (TAVR) in a randomized controlled trial.

METHODS

A total of 60 patients with chronic HF who received TAVR treatment were randomly divided into the control group (n = 30) and exercise training (ET) group (n = 30). The control group was treated with conventional rehabilitation, and the ET group was given personalized exercise-based CR based on a cardiopulmonary exercise test (CPX). The CPX parameters, echocardiography, 6-minute walk test distance, and quality of life were evaluated in the two groups.

RESULTS

All patients who completed symptom-restricted CPX showed no complications. After the 12-week rehabilitation period, the levels of anaerobic threshold, peak oxygen uptake, peak oxygen pulse, peak power, left ventricular ejection fraction, and 6-minute walk test distance in the ET group were significantly higher than those in the control group ( P  < .05). Scores on the Minnesota Life with Heart Failure Questionnaire in the ET group were lower than those in the control group ( P < .05).

CONCLUSION

Exercise-based CR significantly improves cardiopulmonary function, exercise tolerance, and quality of life in patients with chronic HF who undergo TAVR.

A statistical model to identify hereditary and epigenetic fusion genes associated with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a heart condition that causes enlarged and weakened left ventricles and affects the heart's ability to pump blood effectively. Most genetic etiology still needs to be understood. Previously, we have used the known germline hereditary fusion genes (HFGs) to identify HFGs associated with multiple myeloma and leukemia. In this study, we have developed a statistical model to study fusion transcripts discovered from the left ventricles of 122 DCM patients and 252 GTEx (Genotype Tissue Expression) healthy controls to discover novel HFGs, ranging from 4% to 87.7%, and EFGs, ranging from 4% to 99.2%, associated with DCM. This discovery of numerous novel HFGs and EFGs associated with DCM provides first-hand evidence that DCM results from interactive developmental consequences between germline genetic and environmental abnormalities and paves the way for future research and diagnostic and therapeutic applications, instilling hope for the future of DCM treatment.

Improving cardiovascular risk stratification through multivariate time-series analysis of cardiopulmonary exercise test data

Nowadays cardiorespiratory fitness (CRF) is assessed using summary indexes of cardiopulmonary exercise tests (CPETs). Yet, raw time-series CPET recordings may hold additional information with clinical relevance. Therefore, we investigated whether analysis of raw CPET data using dynamic time warping combined with k-medoids could identify distinct CRF phenogroups and improve cardiovascular (CV) risk stratification. CPET recordings from 1,399 participants (mean age, 56.4 years; 37.7% women) were separated into 5 groups with distinct patterns. Cluster 5 was associated with the worst CV profile with higher use of antihypertensive medication and a history of CV disease, while cluster 1 represented the most favorable CV profile. Clusters 4 (hazard ratio: 1.30; p = 0.033) and 5 (hazard ratio: 1.36; p = 0.0088) had a significantly higher risk of incident adverse events compared to clusters 1 and 2. The model evaluation in the external validation cohort revealed similar patterns. Therefore, an integrative CRF profiling might facilitate CV risk stratification and management.

Prognostic value of cardiopulmonary exercise test in children with congenital heart defects

BACKGROUND

Cardiopulmonary exercise testing (CPET) has an important prognostic value in adults with different congenital heart defects (CHDs) and is a useful tool for risk stratification and clinical decision-making. In this retrospective study, we studied the prognostic value of CPET in paediatric patients with CHD.

METHODS

411 CPET performed by paediatric patients with different CHDs were evaluated in this retrospective study. Medical records were reviewed to determine the presence of cardiac events. Participants were classified using the 2018 AHA/ACC guideline for the management of adults with CHD that combines anatomical complexity and current physiological stage.

RESULTS

411 patients with a median age at test of 12 years, 51 patients with simple CHD, 170 patients with moderate complexity CHD and 190 with high complexity CHD underwent CPET. Overall, CPET parameters were lower than the reference values (%predicted VO2peak=75% and %predicted oxygen uptake efficiency slope (OUES)=79%), showing worst exercise capacity in the most complex types of CHD (Group III: %predicted VO2peak=72% and %predicted OUES=75%). Seventy-one patients presented with cardiac events at a median time from CPET to first event of 28 months. Patients with cardiac events had lower exercise performance as compared with patients without cardiac events as determined by the submaximal variables (%predicted OUES: HR=2.6 (1.5-4.4), p<0.001 and VE/VCO2: HR=2.2 (1.4-3.5), p=0.001).

CONCLUSION

Reduced exercise capacity at young age is related to a higher probability of future cardiovascular events in paediatric patients with CHD. Submaximal exercise variables can be used instead when maximal exercise cannot be achieved.

Identifying limitations to exercise with incremental cardiopulmonary exercise testing: a scoping review

Cardiopulmonary exercise testing (CPET) is a comprehensive and invaluable assessment used to identify the mechanisms that limit exercise capacity. However, its interpretation remains poorly standardised. This scoping review aims to investigate which limitations to exercise are differentiated by the use of incremental CPET in literature and which criteria are used to identify them. We performed a systematic, electronic literature search of PubMed, Embase, Cochrane CENTRAL, Web of Science and Scopus. All types of publications that reported identification criteria for at least one limitation to exercise based on clinical parameters and CPET variables were eligible for inclusion. 86 publications were included, of which 57 were primary literature and 29 were secondary literature. In general, at the level of the cardiovascular system, a distinction was often made between a normal physiological limitation and a pathological one. Within the respiratory system, ventilatory limitation, commonly identified by a low breathing reserve, and gas exchange limitation, mostly identified by a high minute ventilation/carbon dioxide production slope and/or oxygen desaturation, were often described. Multiple terms were used to describe a limitation in the peripheral muscle, but all variables used to identify this limitation lacked specificity. Deconditioning was a frequently mentioned exercise limiting factor, but there was no consensus on how to identify it through CPET. There is large heterogeneity in the terminology, the classification and the identification criteria of limitations to exercise that are distinguished using incremental CPET. Standardising the interpretation of CPET is essential to establish an objective and consistent framework.

Inter- and intra-observer reliability and agreement of O2Pulse inflection during cardiopulmonary exercise testing: A comparison of subjective and novel objective methodology

Cardiopulmonary exercise testing (CPET) is the 'gold standard' method for evaluating functional capacity, with oxygen pulse (O2Pulse) inflections serving as a potential indicator of myocardial ischaemia. However, the reliability and agreement of identifying these inflections have not been thoroughly investigated. This study aimed to assess the inter- and intra-observer reliability and agreement of a subjective quantification method for identifying O2Pulse inflections during CPET, and to propose a more robust and objective novel algorithm as an alternative methodology. A retrospective analysis was conducted using baseline data from the HIIT or MISS UK trial. The O2Pulse curves were visually inspected by two independent examiners, and compared against an objective algorithm. Fleiss' Kappa was used to determine the reliability of agreement between the three groups of observations. The results showed almost perfect agreement between the algorithm and both examiners, with a Fleiss' Kappa statistic of 0.89. The algorithm also demonstrated excellent inter-rater reliability (ICC) when compared to both examiners (0.92-0.98). However, a significant level (P ≤0.05) of systematic bias was observed in Bland-Altman analysis for comparisons involving the novice examiner. In conclusion, this study provides evidence for the reliability of both subjective and novel objective methods for identifying inflections in O2Pulse during CPET. These findings suggest that further research into the clinical significance of O2Pulse inflections is warranted, and that the adoption of a novel objective means of quantification may be preferable to ensure equality of outcome for patients.

[Contribution of the 6-minutes walking test and the plasma NT-proBNP at admission and discharge to the prognostic evaluation of patients with NYHA class II-III Heart Failure.]

OBJECTIVE

To study the 6MWT and NT-proBNP contribution to the prognosis evaluation of patients with NYHA class II-III heart failure in the Yalgado Ouédraogo Teaching Hospital.

METHODS

We carried out a nine months prospective observational cohort from the 1st February to the 31st October 2020. Patients with NYHA class II-III HF who consented to participate were included in the study. We identified two variables of interest: death and readmission.

RESULTS

We included 50 patients with congestive heart failure representing 37.3% of heart failure. The average follow up time of patients was 154.58 ± 74.8 days. Twelve patients (24%) were readmited and 11 passed away with five during hospitalisation. On admission, The average distance on the 6MWT (194.6 ± 85.5 m) on admission and average NT-proBNP (5812.1±4729.4 ng/L) measured on admission and before discharge wasn't significantly correlated to the risk of death and re-hospitalisation. The average distance on the 6MWT before discharge (306.2±84.6) was significantly correlated to an increase risk of death and re-hospitalisation. Patients with an increase in NT-proBNP superior to 30% from measurement on admission to the one before discharge had a high risk of re-hospitalisation and death compare to those with a decrease of more than 30% with a moderate to good correlation coefficient of 0.6 between the two.

CONCLUSION

6MWT and NT-proBNP variations from admission to discharge have been necessary to evaluate the prognosis of patients with CHF.

Prognostic Value of Cardiopulmonary Exercise Test Parameters in Ventricular Assist Device Therapy

Cardiopulmonary exercise test (CPET) parameters are established prognosticators in heart failure. However, the prognostic value of preimplantation and postimplantation CPET parameters in left ventricular assist device (LVAD) therapy is unclear and it is evaluated in this study. Adult patients who were implanted with an LVAD and underwent CPET during the preimplantation or postimplantation period were retrospectively analyzed. Five CPET parameters were calculated: vO2 max, oxygen uptake efficiency slope (OUES), VE/vCO2 Slope, VE/vCO2 min, and VE/vCO2 max. The relationship between CPET parameters and postimplantation outcomes was evaluated with multivariable analysis. Pre and postimplantation CPET cohorts included 191 and 122 patients, respectively. Among preimplantation CPET parameters: vO2 max and OUES were associated with 1, 3, and 5 year mortality, VE/vCO2 min was associated with 3 and 5 year mortality, whereas VE/vCO2 Slope was associated with 5 year mortality. From postimplantation CPET parameters: vO2 max was an independent predictor of 3 and 5 year mortality, whereas VE/vCO2 max was an independent predictor of 3 year mortality following LVAD implantation. Preimplantation CPET parameters have a prognostic value for long-term survival following LVAD implantation, whereas their association with early postimplantation outcomes appears to be weaker. Postimplantation vO2 max and VE/vCO2 max values are associated with survival on device support and may provide a second chance for prognostication in patients without preimplantation CPET data.

Exercise capacity following ventricular assist device implantation via thoracotomy with outflow cannula anastomosis to the descending aorta

Left ventricular assist device (LVAD) implantation via left lateral thoracotomy with outflow cannula anastomosis to the descending aorta is an alternative technique that avoids anterior mediastinal planes and requires a single incision. This study compares changes in exercise capacity following LVAD implantation with outflow cannula anastomosis to the descending aorta versus ascending aorta. Adult patients who received a continuous flow centrifugal LVAD implantation and completed both pre- and postimplantation cardiopulmonary exercise tests (CPETs) and or 6-minute walk tests (6MWT) were included. Change in CPET parameters (maximum oxygen intake: vO₂ max, oxygen uptake efficiency ratio: OUES, ventilatory efficiency ratio: vE/vCO₂ Slope) and 6MWT distance were compared between ascending and descending aorta anastomosis groups. Ascending and descending aorta anastomosis cohorts included 59 and 14 patients, respectively. Pre- and postimplantation CPETs were performed 63 ± 12 days before and 216 ± 17 days following implantation. The improvement in CPET parameters (vO₂ max, OUES, vE/vCO₂ Slope) or 6MWT distance was not significantly different between the ascending and descending aorta anastomosis groups. This study found no significant difference in the improvement of CPET parameters or 6MWT distance between LVAD implantation via thoracotomy with outflow cannula anastomosis to descending aorta and standard implantation via sternotomy with outflow cannula anastomosis to ascending aorta.

In patients with heart failure, enhanced ventilatory response to exercise is associated with severe obstructive sleep apnea

STUDY OBJECTIVES

Patients with chronic heart failure (CHF) while undergoing exercise test, frequently exhibit elevated ratio of minute ventilation over CO₂ output (VE/VCO₂ slope). One of the factors contributing to this elevated slope is increased chemosensitivity to CO₂, as this slope significantly correlates with the slope of the ventilatory response to CO₂ rebreathing at rest. A previous study in patients with CHF and central sleep apnea (CSA) has shown the highest VE/VCO2 slope during exercise was associated with the most severe CSA. In the current study, we tested the hypothesis that in patients with CHF and obstructive sleep apnea (OSA), the highest VE/VCO₂ slope is also associated with most severe OSA. If correct, it implies that in CHF, augmented instability in the negative feedback system controlling breathing predisposes to both OSA and CSA.

METHODS

This preliminary study involved 70 patients with stable CHF and spectrum of OSA severity who underwent full night polysomnography, echocardiography, and cardiopulmonary exercise testing. Peak oxygen consumption (VO₂ max) and VE/VCO₂ slope were calculated.

RESULTS

There were significant positive correlations between apnea hypopnea index (AHI) and VE/VCO₂ slope (r= 0.359; p=0.002). In the regression model, involving relevant variable, age, body mass index, gender, VE/VCO₂ slope, VO₂, and left ventricular ejection fraction, AHI retained significance with VE/VCO₂.

CONCLUSIONS

In patients with CHF, the VE/VCO₂ slope obtained during exercise correlates significantly to the severity of OSA suggesting that an elevated CO₂ response should increase suspicion for presence of severe OSA, a treatable disorder that is potentially associated with excess mortality.

CLINICAL TRIAL REGISTRATION: REGISTRY

ClinicalTrials.gov; Title: Comparison Between Exercise Training and CPAP Treatment for Patients With Heart Failure and Sleep Apnea; Identifier: NCT01538069; URL: https://clinicaltrials.gov/ct2/show/record/NCT01538069.

Mid-arm muscle circumference as an indicator of exercise tolerance in chronic heart failure

AIM

Skeletal muscle mass is associated with exercise tolerance in patients with chronic heart failure (CHF). Anthropometric indicators are used to evaluate skeletal muscle mass, as these can be easily assessed in clinical practice. However, the association between anthropometric indicators and exercise tolerance is unclear. This study aimed to investigate the association between anthropometric indicators and exercise tolerance in CHF patients.

METHODS

We evaluated 69 patients with CHF. Mid-arm circumference, mid-arm muscle circumference (MAMC), calf circumference and body mass index were measured as the anthropometric indicators. Exercise tolerance was evaluated according to the peak oxygen uptake (VO₂ ). Correlation analyses were carried out to determine the association between peak VO₂ and anthropometric indicators. Furthermore, univariate and multiple regression analyses were carried out using peak VO₂ as the dependent variable, and age, male, left ventricular ejection fraction, angiotensin II receptor blocker or angiotensin converting enzyme inhibitor, diuretics, B-type natriuretic peptide, estimated glomerular filtration rate, hemoglobin and anthropometric indicators as the independent variables.

RESULTS

There were significant positive correlations between the peak VO₂ and mid-arm circumference (r_s = 0.378, P = 0.001), MAMC (r = 0.634, P < 0.001) and calf circumference (r = 0.292, P = 0.015). In multiple regression analysis, MAMC (β = 0.721, P < 0.001) and estimated glomerular filtration rate (β = 0.279, P = 0.007) were independent factors associated with peak VO₂ .

CONCLUSIONS

MAMC is independently associated with peak VO₂ in CHF patients. Thus, MAMC could be an indicator of exercise tolerance, which is closely related to the severity and prognosis of CHF. Geriatr Gerontol Int 2021; 21: 411-415.

Effect of Aerobic Exercise on Peak Oxygen Consumption, VE/VCO2 Slope, and Health-Related Quality of Life in Patients with Heart Failure with Preserved Left Ventricular Ejection Fraction: a Systematic Review and Meta-Analysis

PURPOSE OF REVIEW

The aim of this study was to determine the effects of aerobic exercise on peak oxygen uptake (peak VO₂), minute ventilation/carbon dioxide production (VE/VCO₂ slope), and health-related quality of life (HRQoL) among patients with heart failure (HF) and preserved ejection fraction (HFpEF).

RECENT FINDINGS

We conducted a Cochrane Library, MEDLINE/PubMed, Physiotherapy Evidence Database, and SciELO search (from 1985 to May 2019) for randomized controlled trials that evaluated the effects of aerobic exercise in HFpEF patients. We calculated the mean differences (MD) and 95% confidence interval (CI). Ten intervention studies were included providing a total of 399 patients. Compared with control, aerobic exercise resulted in improvement in peak VO₂ MD 1.9 mL kg^-1 min^-1 (95% CI 1.3 to 2.5; N = 314) and HRQoL measured by Minnesota Living with Heart Failure MD 5.4 (95% CI - 10.5 to - 0.2; N = 256). No significant difference in VE/VCO₂ slope was found between participants in the aerobic exercise group and the control group. The quality of evidence for peak VO₂ and HRQoL was assessed as being moderate. Aerobic exercise moderately improves peak VO₂ and HRQoL and should be considered a strategy of rehabilitation of HFpEF individuals.

Effects of Exercise Training and CPAP in Patients With Heart Failure and OSA: A Preliminary Study

BACKGROUND

Exercise and CPAP improve OSA. This study examined the effects of exercise in patients with heart failure (HF) and OSA.

METHODS

Patients with HF and OSA were randomized to the following study groups: control, exercise, CPAP, and exercise + CPAP.

RESULTS

Sixty-five participants completed the protocol. Comparing baseline vs 3 months, the mean apnea-hypopnea index (AHI) did not change significantly (in events per hour) in the control group, decreased moderately in the exercise group (28 ± 17 to 18 ± 12; P < .03), and decreased significantly more in the CPAP group (32 ± 25 to 8 ± 11; P < .007) and in the exercise + CPAP group (25 ± 15 to 10 ± 16; P < .007). Peak oxygen consumption, muscle strength, and endurance improved only with exercise. Both exercise and CPAP improved subjective excessive daytime sleepiness, quality of life, and the New York Heart Association functional class. However, compared with the control group, changes in scores on the 36-item Medical Outcomes Study Short Form Survey and Minnesota Living with Heart Failure Questionnaire were only significant in the exercise groups.

CONCLUSIONS

In patients with HF and OSA, our preliminary results showed that exercise alone attenuated OSA and improved quality of life more than CPAP. In the landscape treatment of OSA in patients with HF, this analysis is the only randomized trial showing any treatment (in this case, exercise) that improved all the studied parameters. The results highlight the important therapeutic benefits of exercise, particularly because adherence to CPAP is low.

Stair-Climbing Test Predicts Postoperative Cardiopulmonary Complications and Hospital Stay in Patients with Non-Small Cell Lung Cancer

Background

There is currently no reliable method to predict major postoperative cardiopulmonary complications for patients with non-small cell lung cancer (NSCLC). In this study, we hypothesized that exercise oxygen desaturation (EOD) and heart rate change results in a stair-climbing test (SCT) would predict postoperative cardiopulmonary complications for patients with NSCLC.

Material/Methods

We examined 171 patients (41 females and 130 males) with NSCLC by preoperative SCT from January 2010 to July 2015. Among them, 27 underwent wedge resection, 122 underwent lobectomy, and 22 underwent pneumonectomy. The correlation between postoperative cardiopulmonary complications and parameters of SCT and pulmonary function test (PFT) parameters were analyzed retrospectively.

Results

The overall 30-day postoperative morbidity of the patients was 46/171 (26.9%), with death occurring in 3/171(1.8%). The age, FEV1%, MVV, height of climbing, EOD, and heart rate change were found to be significantly different between the group with postoperative cardiopulmonary complications and those without. Binary logistic regression analysis showed that EOD and heart rate change were independently correlated with postoperative cardiopulmonary complications. In addition, a model predicting the probability of postoperative cardiopulmonary complication based on logistic regression for multivariable analysis was used to confirm our findings.

Conclusions

A symptom-limited SCT with oxygen saturation monitoring is a safe, simple, and low-cost method to evaluate cardiopulmonary function preoperatively.

A Reduction in Maximal Incremental Exercise Test Duration 48 h Post Downhill Run Is Associated with Muscle Damage Derived Exercise Induced Pain

Purpose: To examine whether exercise induced muscle damage (EIMD) and muscle soreness reduce treadmill maximal incremental exercise (MIE) test duration, and true maximal physiological performance as a consequence of exercise induced pain (EIP) and perceived effort.

Methods: Fifty (14 female), apparently healthy participants randomly allocated into a control group (CON, n = 10), or experimental group (EXP, n = 40) visited the laboratory a total of six times: visit 1 (familiarization), visit 2 (pre 1), visit 3 (pre 2), visit 4 (intervention), visit 5 (24 h post) and visit 6 (48 h post). Both groups performed identical testing during all visits, except during visit 4, where only EXP performed a 30 min downhill run and CON performed no exercise. During visits 2, 3, and 6 all participants performed MIE, and the following measurements were obtained: time to exhaustion (TTE), EIP, maximal oxygen consumption (V·O2max), rate of perceived exertion (RPE), maximum heart rate (HR_max), maximum blood lactate (BLa_max), and the contribution of pain to terminating the MIE (assessed using a questionnaire). Additionally during visits 1, 2, 3, 5, and 6 the following markers of EIMD were obtained: muscle soreness, maximum voluntary contraction (MVC), voluntary activation (VA), creatine kinase (CK).

Results: There were no significant differences (p ≥ 0.32) between any trials for any of the measures obtained during MIE for CON. In EXP, TTE decreased by 34 s (3%), from pre 2 to 48 h post (p < 0.001). There was a significant association between group (EXP, CON) and termination of the MIE due to “pain” during 48 h post (χ² = 14.7, p = 0.002).

Conclusion: EIMD resulted in premature termination of a MIE test (decreased TTE), which was associated with EIP, MVC, and VA. The exact mechanisms responsible for this require further investigation.

Delayed Anaerobic Threshold in Heart Failure Patients With Atrial Fibrillation

PURPOSE

To assess whether atrial fibrillation (AF) in heart failure (HF) affects oxygen uptake at anaerobic threshold ((Equation is included in full-text article.)O2 AT) and heart rate (HR) kinetics.

METHODS

A total of 15 patients with HF and AF and 18 with HF and sinus rhythm (SR) performed a maximal incremental and 2 constant workload cycle ergometer cardiopulmonary exercise tests (below and above AT, at 25% and 75% of maximal workload, respectively). At constant workload tests, kinetics of (Equation is included in full-text article.)O2 and HR were assessed by calculating time constant (τ).

RESULTS

HF patients with AF showed a similar peak (Equation is included in full-text article.)O2 to those with SR (16.7 ± 4.5 mL/kg/min vs 16.6 ± 3.9 mL/kg/min). However, (Equation is included in full-text article.)O2 AT (11.3 ± 2.9 mL/kg/min vs 9.3 ± 2.8 mL/kg/min; P < .05), peak HR (149 ± 18.8 bpm vs 116.4 ± 20.4 bpm; P < .001), HR AT (125.3 ± 19.1 bpm vs 90.3 ± 15.5 bpm; P < .001), and HR increase during exercise were greater in HF patients with AF. Finally, τHR and τ(Equation is included in full-text article.)O2 below and above AT were not significantly different.

CONCLUSIONS

In HF patients with AF, despite a similar peak (Equation is included in full-text article.)O2 compared with patients with HF and SR, (Equation is included in full-text article.)O2 AT is higher because of a higher HR and a greater HR increase during exercise. One postulated mechanism would be a greater cardiac output increase at the beginning of exercise in HF patients with AF. The delayed AT generates uncertainty about the meaning of a (Equation is included in full-text article.)O2 value at AT in HF patients with AF, because a higher AT is usually associated with better performance and a better prognosis.

[Left ventricle assist device: rehabilitation and management programmes]

Progress in the medical management of patients with heart failure with systolic dysfunction has been accompanied by a significant improvement in survival and quality of life. These strategies have also resulted in changes in the clinical profile as well as an increase in the number of patients with advanced heart failure. The technological developments in left ventricular assist devices provide real hope for these patients. This article related our experience of management and the rehabilitation program realized.

Exercise capacity and N-terminal pro-brain natriuretic peptide levels with biventricular vs. right ventricular pacing for atrioventricular block: results from the PREVENT-HF German Substudy

AIMS

Previous studies showed unfavourable effects of right ventricular (RV) pacing. Ventricular pacing (VP), however, is required in many patients with atrioventricular (AV) block. The PREVENT-HF study explored left ventricular (LV) remodelling during RV vs. biventricular (BIV) pacing in AV block without advanced heart failure. The pre-specified PREVENT-HF German Substudy examined exercise capacity and N-terminal pro-brain natriuretic peptide (NT-proBNP).

METHODS AND RESULTS

Patients with expected VP ≥80% were randomized to RV or BIV pacing. Endpoints were peak oxygen uptake (pVO2), oxygen uptake at the anaerobic threshold (VO2AT), ventilatory efficiency (VE/VCO2), and logNT-proBNP. Considering crossover, intention to treat (ITT), and on-treatment (OT) analyses of covariance (ANCOVA) were performed. For exercise testing 44 (RV: 25, BIV: 19), and for NT-proBNP 53 patients (RV: 29, BIV: 24) were included. The ITT analysis revealed significant differences in pVO2 [ANCOVA effect 2.83 mL/kg/min, confidence interval (CI) 0.83-4.91, P = 0.007], VO2AT (ANCOVA effect 2.14 mL/min/k, CI 0.14-4.15, P = 0.03), and VE/VCO2 (ANCOVA effect -5.46, CI -10.79 to -0.13, P = 0.04) favouring BIV randomization. The significant advantage in pVO2 persisted in OT analysis, while VO2AT and VE/VCO2 showed trends favouring BIV pacing. LogNT-proBNP did not differ between groups. (ITT: ANCOVA effect 0.008, CI -0.40 to +0.41, P = 0.97; OT: ANCOVA effect -0.03, CI -0.44 to 0.30, P = 0.90).

CONCLUSION

Our study suggests that BIV pacing produces better exercise capacity over 1 year compared with RV pacing in patients without advanced heart failure and AV block. In contrast, we observed no significant changes of NT-proBNP. Larger trials will allow appraising the clinical usefulness of BIV pacing in AV block. ClinicalTrials.gov Identifier: NCT00170326.

Decreased aerobic capacity 4 years after aortic valve replacement in male patients operated upon for chronic aortic regurgitation

Exercise testing is underutilized in patients with valve disease. We have previously found a low physical work capacity in patients with aortic regurgitation 6 months after aortic valve replacement (AVR). The aim of this study was to evaluate aerobic capacity in patients 4 years after AVR, to study how their peak oxygen uptake (peakVO₂) had changed postoperatively over a longer period of time. Twenty-one patients (all men, 52 ± 13 years) who had previously undergone cardiopulmonary exercise testing (CPET) pre- and 6 months postoperatively underwent maximal exercise testing 49 ± 15 months postoperatively using an electrically braked bicycle ergometer. Breathing gases were analysed and the patients' physical fitness levels categorized according to Åstrand's and Wasserman's classifications. Mean peakVO₂ was 22·8 ± 5·1 ml × kg⁻¹ × min⁻¹ at the 49-month follow-up, which was lower than at the 6-month follow-up (25·6 ± 5·8 ml × kg⁻¹ × min⁻¹, P = 0·001). All but one patient presented with a physical fitness level below average using Åstrand's classification, while 13 patients had a low physical capacity according to Wasserman's classification. A significant decrease in peakVO₂ was observed from six to 49 months postoperatively, and the decrease was larger than expected from the increased age of the patients. CPET could be helpful in timing aortic valve surgery and for the evaluation of need of physical activity as part of a rehabilitation programme.

Association between right ventricular two-dimensional strain and exercise capacity in patients with either idiopathic or ischemic dilated cardiomyopathy

OBJECTIVES

To detect right ventricular myocardial function in dilated cardiomyopathy (DCM) using two-dimensional strain echocardiography (2DSE) and to evaluate the relationship between right ventricular dysfunction and response to cardiopulmonary exercise test (CPET).

METHODS

Seventy-five DCM patients (44 idiopathic and 31 ischemic) without clinical signs of right ventricular failure underwent standard echo, 2DSE analysis of right ventricle and bicycle CPET.

RESULTS

The two groups were comparable for clinical and standard two-dimensional echocardiographic and Doppler variables, except for right ventricular diameters that were mildly increased in patients with idiopathic DCM. Right ventricular global longitudinal strain (RV GLS) and regional peak myocardial right ventricular strain were significantly impaired in patients with idiopathic DCM compared with ischemic DCM (both P<0.001). A significant correlation was detectable among RV GLS and VO2 peak percentage (r= -0.65, P<0.0001), VE/VCO2 slope (r=0.35, P<0.01), maximum work rate percentage (r= -0.55, P<0.001) and peak circulatory power (r=0.53, P<0.001). These correlations with RV GLS remained significant even in multivariate analysis.

CONCLUSION

2DSE represents a promising noninvasive technique to assess right ventricular myocardial function in patients with DCM. Reduced right ventricular myocardial deformation is related to decreased ability to perform aerobic exercise and work rate, and to impaired ventilatory response.

Effects of home-based exercise training for patients with chronic heart failure and sleep apnoea: a randomized comparison of two different programmes

Objective: To evaluate the effects of home-based exercise for patients with chronic heart failure and sleep apnoea and to compare two different training programmes.

Design: A randomized, prospective controlled trial.

Setting: Department of Cardiology, University Hospital, Brazil.

Subjects: Fifty chronic heart failure patients with sleep apnoea were randomized in three groups: Group 1 (aerobic training, n = 18), Group 2 (aerobic with strength training, n = 18), and Group 3 (untrained, n = 14).

Interventions: The training programme for Groups 1 and 2 began with three supervised exercise sessions, after they underwent three months of home-based exercise. Patients were followed by weekly telephone call and were reviewed monthly. Group 3 had the status of physical activity evaluated weekly by interview to make sure they remained untrained.

Main outcome measures: At baseline and after three months: cardiopulmonary exercise testing, isokinetic strength and endurance, Minnesota living with heart failure questionnaire and polysomnography. Adherence was evaluated weekly.

Results: Of the 50 patients enrolled in the study, 45 completed the programme. Clinical events: Group 1 (one death), Group 2 (one myocardial infarction), Group 3 (one death and two strokes). None were training related. Training groups showed improvement in all outcomes evaluated and the adherence was an important factor (Group 1 = 98.5% and Group 2 = 100.2%, P = 0.743). Untrained Group 3 demonstrated significant decrease or no change on measurements after three months without training.

Conclusion: Home-based exercise training is an important therapeutic strategy in chronic heart failure patients with sleep apnoea, and strength training resulted in a higher increase in muscle strength and endurance.

Relationship between peak cardiac pumping capability and selected exercise-derived prognostic indicators in patients treated with left ventricular assist devices

AIM

Exercise-derived variables have been used in the assessment of functional capacity and prognosis in patients with chronic heart failure. The aim of this study was to assess the relationship between cardiac pumping capability represented by peak cardiac power output and peak oxygen consumption, anaerobic threshold, ventilatory efficiency slope, and peak circulatory power in patients undergoing the 'Harefield Protocol'.

METHODS AND RESULTS

Haemodynamic and gas exchange measurements were undertaken during a graded treadmill exercise test. They were performed on 54 patients-18 implanted with left ventricular assist devices (LVADs), 16 explanted (recovered), and 20 moderate-to-severe heart failure patients. Peak oxygen consumption was only highly correlated with peak cardiac power output in explanted LVAD (r = 0.85, P< 0.01), but not in implanted LVAD and heart failure patients (r = 0.55 and 0.53, P< 0.05). The anaerobic threshold was only modestly correlated with peak cardiac power output in heart failure and explanted (r = 0.46 and 0.54, P< 0.05) and weakly in implanted LVAD patients (r = 0.37, P< 0.05). Peak cardiac power output was well correlated with peak circulatory power in LVAD explanted and implanted (r = 0.82, P< 0.01; r = 0.63, P< 0.01) but not in heart failure patients (r = 0.31, P> 0.05). Ventilatory efficiency slope was only moderately correlated with peak cardiac power output in LVAD-explanted patients (r = -0.52, P< 0.05).

CONCLUSION

Exercise-derived prognostic indicators demonstrate limited capacity in reflecting cardiac pumping capability in patients treated with LVADs and should therefore be used with caution in interpretation of cardiac organ function.

A case for assessment of oscillatory breathing during cardiopulmonary exercise test in risk stratification of elderly patients with chronic heart failure

The prognostic value of exercise oscillatory breathing (EOB) during cardiopulmonary test (CPX) has been described in young chronic heart failure (HF) patients. We assessed the prognostic role of EOB vs other clinical and ventilatory parameters in elderly HF patients performing a maximal CPX.

METHODS AND RESULTS

We prospectively followed-up 370 HF outpatients ≥ 65 years after a symptom limited CPX. We tested the predictive value of clinical and ventilatory parameters for all-cause mortality and a composite of all-cause mortality and HF hospitalizations. Median age was 74 years, 51% had ischemic heart disease, 25% NYHA class III; ejection fraction was 41% [34-50]. Peak oxygen consumption (PVO(2)) was 11.9 [9.9-14] mL/kg/min, the slope of the regression line relating ventilation to CO(2) output, (VE/VCO(2) slope) was 33.9 [29.8-39.2]. EOB was found in 58% of patients. At follow-up, 84 patients died and overall 158, using a time-to-first event approach, met the composite end-point. Independent predictors of all-cause mortality were CPX EOB and the ratio of VE/VCO(2) slope to peak VO(2), hemoglobin, creatinine and body mass index. The area under the ROC curve (AUC) of the Cox multivariable model was 0.80 (95% CI 0.73 to 0.87). Independent predictors of the composite end-point were EOB, VE/VCO(2) slope, hemoglobin and HF admissions in the previous year (Model AUC 0.75) (95% CI 0.69 to 0.81).

CONCLUSIONS

Among elderly HF patients, EOB prevalence is higher than middle-aged cohorts. EOB and the ratio of VE/VCO(2) slope to peak VO(2) resulted the strongest ventilatory predictor of all-cause mortality, independent of ventricular function.

[The ventilatory response in chronic heart failure population]

Symptom-limited exercise test with peak oxygen consumption measurement possesses a strong prognostic value in chronic heart failure. This parameter allowing notably the selection of patients for heart transplant. Nevertheless, sub maximal effort and beta blocker therapy tend to limit its prognostic value. The ventilatory response evaluated by the minute ventilation - carbon dioxide production (VE/VCO2) linear regression slope during effort is generally considered to be a significant predictor of mortality and hospitalizations in HF population. An enhanced ventilatory response is correlated with a poorer prognostic. In addition, this parameter is not influenced by the intensity of the effort neither by the betablocker therapy. But, physiological determinants are not clear yet. Aim of our study is to confirm the important place of the (VE/VCO2) slope in HF patient's evaluation.

Lower extremity performance measures predict long-term prognosis in older patients hospitalized for heart failure

BACKGROUND

In older heart failure (HF) patients, survival depends on the severity of their cardiac condition and on their functional status. Lower extremity performance, assessed with the Short Physical Performance Battery (SPPB), predicts survival in older persons, both in epidemiologic and clinical settings. We evaluated whether SPPB predicts long-term survival in older subjects hospitalized for HF, independent of traditional measures of HF severity.

METHODS AND RESULTS

Subjects aged 65+ years were enrolled on discharge after hospitalization for decompensated HF. Participants underwent echocardiography, comprehensive geriatric assessment, and SPPB. Cox proportional hazards regression models were used to predict survival over a 30-month follow-up. Of 157 participants (mean age 80 years, range 65-101; 50% men), 61 died. After adjustment for potential confounders, including demographics, ejection fraction, New York Heart Association classification, and comorbidity, we found a graded independent association between SBBP score and mortality risk: compared with an SPPB score of 9-12, scores of 0, 1-4, and 5-8 were associated with hazard ratios (HR) and 95% confidence interval (CI) of death of 6.06 (2.19-16.76), 4.78 (1.63-14.02), and 1.95 (0.67-5.70), respectively.

CONCLUSIONS

SPPB is an independent predictor of long-term survival of older subjects hospitalized for decompensated HF.

Impact of different diagnostic criteria on the prevalence and prognostic significance of exertional oscillatory ventilation in patients with chronic heart failure

INTRODUCTION

Exertional oscillatory ventilation (EOV) occurs in many patients with chronic heart failure. Two different definitions of EOV have been proposed by Corrá and Leite. We aimed to compare the prevalence of EOV and its prognostic significance in patients with chronic heart failure using the two diagnostic approaches.

METHODS

Patients underwent a symptom-limited, treadmill-based exercise test with metabolic gas exchange measurements using the modified Bruce protocol. EOV was defined (i) as cyclic fluctuations in ventilation lasting for more than 60% of exercise duration, with an amplitude of greater than 15% of the average amplitude of cyclic fluctuations at rest (Corrá) and/or (ii) as three or more regular oscillations with regularity defined if the standard deviation of three consecutive cycle lengths was within 20% of the average coupled with a minimal average amplitude of ventilatory oscillation of 5 l (Leite).

RESULTS

Two hundred and forty patients (mean age 59+/-13 years; 73% males; left ventricular ejection fraction 34+/-6%; peak VO2 21.0+/-4.6 ml/kg per min; VE/VCO2 slope 35+/-9) were included in the study. The prevalence of EOV was 25% using the Corrá method and 31% using the Leite method. Fifty percent of patients diagnosed with EOV by the Corrá criteria and 58% diagnosed by the Leite criteria had died at 12-month follow-up. EOV (Corrá) was a predictor of mortality independent of peak VO2, VE/VCO2 slope, left ventricular ejection fraction, age, and 6-min walk test distance. A hazard ratio (HR) of 6.3 (P<0.0001; 95% confidence interval=1.6-25.2) was evident for the Corrá method, which was higher than for the Leite method (HR=4.9; P<0.0001; 95% confidence interval=2.6-18.2).

CONCLUSION

The prevalence of EOV was between 25 and 31% depending on the criteria used to define it. The presence of EOV was a powerful predictor of adverse outcome, and diagnosed with the Corrá criteria was associated with a higher HR than the Leite criteria.

Reduction in circulating testosterone relates to exercise capacity in men with chronic heart failure

BACKGROUND

We investigated whether anabolic deficiency was linked to exercise intolerance in men with chronic heart failure (CHF). Anabolic hormones (testosterone, dehydroepiandrosterone sulfate, insulin-like growth factor 1 [IGF1]) contribute to exercise capacity in healthy men. This issue remains unclear in CHF.

METHODS AND RESULTS

We studied 205 men with CHF (age 60 +/- 11 years, New York Heart Association [NYHA] Class I/II/III/IV: 37/95/65/8; LVEF [left ventricular ejection fraction]: 31 +/- 8%). Exercise capacity was expressed as peak oxygen consumption (peak VO(2)), peak O(2) pulse, and ventilatory response to exercise (VE-VCO(2) slope). In multivariable models, reduced peak VO(2) (and reduced peak O(2) pulse) was associated with diminished serum total testosterone (TT) (P < .01) and free testosterone (eFT; estimated from TT and sex hormone globulin levels) (P < .01), which was independent of NYHA Class, plasma N-terminal pro-brain natriuretic peptide, and age. These associations remained significant even after adjustment for an amount of leg lean tissue. In multivariable models, high VE-VCO(2) slope was related to reduced serum IGF1 (P < .05), advanced NYHA Class (P < .05), increased plasma NT-proBNP (P < .0001), and borderline low LVEF (P = .07). In 44 men, reassessed after 2.3 +/- 0.4 years, a reduction in peak VO(2) (and peak O(2) pulse) was accompanied by a decrease in TT (P < .01) and eFT (P <or= .01). Increase in VE-VCO(2) slope was related only to an increase in plasma NT-proBNP (P < .05).

CONCLUSIONS

In men with CHF, low circulating testosterone independently relates to exercise intolerance. The greater the reduction of serum TT in the course of disease, the more severe the progression of exercise intolerance. Whether testosterone supplementation would improve exercise capacity in hypogonadal men with CHF requires further studies.