Exercise and Sports Science Australia position statement on exercise training and chronic heart failure

Chronic heart failure (CHF) is a complex syndrome characterised by progressive decline in left ventricular function, low exercise tolerance and raised mortality and morbidity. Regular exercise participation has been shown to be a safe and effective treatment modality in the majority of CHF patients, partially reversing some of the maladaptations evident in myocardial and skeletal muscle function, and resulting in improvements in physical fitness and quality of life, and perhaps reduced mortality. The volume and intensity of exercise that is recommended depends on the syndrome severity, however in most patients it should consist of a combination of low-to-moderate intensity aerobic (endurance) exercise on most days of the week and individually prescribed low-to-moderate intensity resistance (strength) training at least twice per week. Additionally, all patients should be closely monitored prior to and during exercise for contraindications by an appropriately trained health professional. The purpose of this statement is to inform and guide exercise practitioners and health professionals in the safe and effective prescription and supervision of exercise for patients with CHF.

Comparing methods for prescribing exercise for individuals with chronic heart failure

This study examined the accuracy of current recommended guidelines for prescribing exercise intensity using the methods of percentage of heart rate reserve (%HRR), percentage of VO₂ peak (%VO₂peak) and percentage of VO₂ reserve (%VO₂R) in a clinical population of chronic heart failure (CHF) patients. The precision of prescription of exercise intensity for 45 patients with stable CHF (39:6 M:F, 65±9 yrs (mean±SD)) was investigated. VO₂peak testing is relatively common among patients with cardiac disease, but the assessment of VO₂rest is not common practice and the accepted standard value of 3.5 mL/kg/min is assumed in the application of %VO2R (%VO₂R_3.5). In this study, VO₂rest was recorded for 3 min prior to the start of a symptom-limited exercise test on a cycle ergometer. Target exercise intensities were calculated using the VO₂ corresponding to 50 or 80 %HRR, VO₂peak and VO₂R. The VO₂ values were then converted into prescribed speeds on a treadmill in km/hr at 1 %grade using ACSM’s metabolic equation for walking. Target intensities and prescribed treadmill speeds were also calculated with the %VO₂R method using the mean VO₂rest value of participants (3.9 mL/kg/min) (%VO₂R_3.9). This was then compared to the exercise intensities and prescribed treadmill speeds using patient’s measured VO₂rest. Error in prescription correlates the difference between %VO₂R_3.5 and %VO₂R_3.9 compared to %VO₂R with measured VO₂rest. Prescription of exercise intensity through the %HRR method is imprecise for patients on medications that blunt the HR response to exercise. %VO₂R method offers a significant improvement in exercise prescription compared to %VO₂peak. However, a disparity of 10 % still exists in the %VO₂R method using the standard 3.5 mL/kg/min for VO₂rest in the %VO₂R equation. The mean measured VO₂rest in the 45 CHF patients was 11 % higher (3.9±0.8 mL/kg/min) than the standard value provided by ACSM. Applying the mean measured VO₂rest value of 3.9 mL/kg/min rather than the standard assumed value of 3.5 mL/kg/min proved to be closer to the prescribed intensity determined by the actual measured resting VO₂. These results suggest that the %HRR method should not be used to prescribe exercise intensity for CHF patients. Instead, VO₂ should be used to prescribe exercise intensity and be expressed as %VO₂R with measured variables (VO₂rest and VO₂peak).

Moderate-intensity resistance exercise training in patients with chronic heart failure improves strength, endurance, heart rate variability, and forearm blood flow

Thirty-nine CHF patients (New York Heart Association Functional Class = 2.3±0.5; left ventricular ejection fraction 28%±7%; age 65±11 years; 33:6 male:female) underwent 2 identical series of tests, 1 week apart, for strength and endurance of the knee and elbow extensors and flexors, VO_2peak, HRV, FBF at rest, and FBF activated by forearm exercise or limb ischemia. Patients were then randomized to 3 months of resistance training (EX, n = 19), consisting of mainly isokinetic (hydraulic) ergometry, interspersed with rest intervals, or continuance with usual care (CON, n = 20), after which they underwent repeat endpoint testing. Combining all 4 movement patterns, strength increased for EX by 21±30% (mean±SD, P<.01) after training, whereas endurance improved 21±21% (P<.01). Corresponding data for CON remained almost unchanged (strength P<.005, endurance P<.003 EX versus CON). VO_2peak improved in EX by 11±15% (P<.01), whereas it decreased by 10±18% (P<.05) in CON (P<.001 EX versus CON). The ratio of low-frequency to high-frequency spectral power fell after resistance training in EX by 44±53% (P<.01), but was unchanged in CON (P<.05 EX versus CON). FBF increased at rest by 20±32% (P<.01), and when stimulated by submaximal exercise (24±32%, P<.01) or limb ischemia (26±45%, P<.01) in EX, but not in CON (P<.01 EX versus CON).

Circuit resistance training in chronic heart failure improves skeletal muscle mitochondrial ATP production rate—A randomized controlled trial

Background : We aimed to determine the role of skeletal muscle mitochondrial ATP production rate (MAPR) in relation to exercise tolerance after resistance training (RT) in chronic heart failure (CHF).

Methods and Results : Thirteen CHF patients (New York Heart Association functional class 2.3 ± 0.5; Left ventricular ejection fraction 26 ± 8%; age 70 ± 8 years) underwent testing for peak total body oxygen consumption (VO_2peak), and resting vastus lateralis muscle biopsy. Patients were then randomly allocated to 11 weeks of RT (n = 7), or continuance of usual care (C; n = 6), after which testing was repeated. Muscle samples were analyzed for MAPR, metabolic enzyme activity, and capillary density. VO_2peak and MAPR in the presence of the pyruvate and malate (P+M) substrate combination, representing carbohydrate metabolism, increased in RT (P < .05) and decreased in C (P < .05), with a significant difference between groups (VO_2peak, P = .005; MAPR, P = .03). There was a strong correlation between the change in MAPR and the change in peak total body oxygen consumption (VO_2peak) over the study (r = 0.875; P < .0001), the change in MAPR accounting for 70% of the change in VO_2peak.

Conclusions : These findings suggest that mitochondrial ATP production is a major determinant of aerobic capacity in CHF patients and can be favorably altered by muscle strengthening exercise.

Respiratory muscle dysfunction and training in chronic heart failure

A characteristic feature of chronic heart failure (CHF) is reduced exercise tolerance. Several factors contributing to this have been identified, including alterations in central haemodynamics, skeletal muscle oxygen utilisation and respiratory muscle dysfunction. This review focuses on abnormalities identified in respiratory muscle structure and function in CHF and recent evidence for the benefit of selective inspiratory muscle training in CHF. Included in this review are findings from original investigations, with a specific focus on recent published data.

Patient self-management in chronic heart failure – establishing concordance between guidelines and practice

 Chronic heart failure (CHF) is a progressive and debilitating disease with a broad symptom profile, intermittently marked by periods of acute decompensation. CHF patients are encouraged to self-manage their illness, such as adhering to medical regimens and monitoring symptoms, to optimise health outcomes and quality of life. In so doing, patients are asked to collaborate with their health service providers with regard to their care. However, patients generally do not self-manage well, even with specialist support. Moreover, self- management interventions are yet to demonstrate morbidity or mortality benefits. Social network approaches to self-management consider the availability and mobilisation of all resources, beyond those of only the patient and healthcare providers. Used in conjunction with e-health platforms, social network approaches may offer a means by which to optimise self-management programmes of the future.

Temporal dynamics of the circadian heart rate following low and high volume exercise training in sedentary male subjects

Purpose: Increased risk of arrhythmic events occurs at certain times during the circadian cycle with the highest risk being in the second and fourth quarter of the day. Exercise improves treatment outcome in individuals with cardiovascular disease. How different exercise protocols affect the circadian rhythm and the associated decrease in adverse cardiovascular risk over the circadian cycle has not been shown. Methods: Fifty sedentary male participants were randomized into an 8-week high volume and moderate volume training and a control group. Heart rate was recorded using Polar Electronics and investigated with Cosinor analysis and by Poincaré plot derived features of SD1, SD2 and the complex correlation measure (CCM) at 1-h intervals over the 24-h period. Results: Moderate exercise significantly increased vagal modulation and the temporal dynamics of the heart rate in the second quarter of the circadian cycle (p = 0.004 and p = 0.007 respectively). High volume exercise had a similar effect on vagal output (p = 0.003) and temporal dynamics (p = 0.003). Cosinor analysis confirms that the circadian heart rate displays a shift in the acrophage following moderate and high volume exercise from before waking (1st quarter) to after waking (2nd quarter of day). Conclusions: Our results suggest that exercise shifts vagal influence and increases temporal dynamics of the heart rate to the 2nd quarter of the day and suggest that this may be the underlying physiological change leading to a decrease in adverse arrhythmic events during this otherwise high-risk period.

Assessment of cognitive function in heart failure patients

Background
Research on the cognitive capacity of heart failure patients is limited, with a paucity of benchmark information available for this population. It is highly likely that cognitive deficits affect patients' understanding of disease and treatment requirements, as well as limiting their functional capacity and ability to implement treatment plans, and undertake self-care.

Aims
The purpose of this study was to establish a comprehensive neurocognitive profile of the heart failure patient through systematic neurocognitive assessment and to determine whether an association existed between severity of heart failure and cognitive abilities.

Methods
Thirty-eight patients were recruited from the heart failure patient databases of two metropolitan hospitals in Melbourne, Australia. Participants were individually assessed using four standardised, internationally recognised neuropsychological tests that examined current and premorbid intelligence, memory and executive functioning.

Results
Although there was no significant decline from premorbid general intellectual function, other specific areas of deficit, including impaired memory and executive functioning, were identified. There were no significant correlations between heart failure severity and the neurocognitive measures used.

Conclusion
The results support the need to recognise cognitive impairment in people with heart failure and to develop an abbreviated method of assessing cognitive function that can be easily implemented in the clinical setting. Identifying cognitive deficits in this population will be useful in guiding the content and nature of treatment plans to maximise adherence and minimise worsening of heart failure symptoms.

Rationale and design of the national benchmarking and evidence-based national clinical guidelines for chronic heart failure management programs study

OBJECTIVES: The National Benchmarks and Evidence-Based National Clinical Guidelines for Heart Failure Management Programs Study is a national, multicenter study designed to determine the nature, range, and effect of interventions applied by chronic heart failure management programs (CHF-MPs) throughout Australia on patient outcomes. Its primary objective is to use these data to develop national benchmarks and evidence-based clinical guidelines and optimize their cost-effective application by reducing quality and outcome variability. DATA SOURCES/STUDY SETTING: Primary data will be collected from CHF-MP coordinators and CHF patients enrolled in these programs on a national basis. Secondary outcome data will be collected from a national morbidity record and from patients' medical records. STUDY DESIGN: Stage I of the study involves a prospective clinical audit of all CHF-MPs throughout Australia (n = 45) to determine the extent of variability in programs currently. Stage II is a prospective cross-sectional survey design enrolling 1,500 patients (average of 40 patients per program) to firstly determine the typical profile of patients being managed via a CHF-MP in Australia and, secondly, the subsequent morbidity and mortality during the 6-month follow-up. Outcome data will be subject to multivariate analysis to determine the key components of care in this regard. All study data will be then examined in the final stage of the study (III) to develop national benchmarks for the application and auditing of CHF-MPs in Australia. CONCLUSION: Variability in patient outcomes is a product of heterogeneity among CHF-MPs. The development of national benchmarks will minimize such heterogeneity and will provide a greater level of evidence for their cost-effective application.

Extent of heart failure self-care as an endpoint to patient education: a literature review

Background: In western countries the number of chronic heart failure (CHF) management programs has escalated in recent times. One key component of them is to teach self-care behaviours that enable affected individuals to monitor themselves and engage in lifestyles that improve their health status.
Aim: The aim of this article is to describe CHF self-care management and to review the literature which examines the effectiveness of patient education on patients’ performance of self-care behaviours.
Design/method: bibliographical databases were searched for papers published in English between 1982 to 2006. The search used the key words: heart failure, education, self-care and measures. Only randomized controlled trials (RCTs) were selected.
Results: Ten randomized controlled trials were selected that used education as an intervention and, in total, 1064 patients with CHF participated in these studies. The studies were heterogenous as to the sample population, the health outcomes measured, the education interventions, the expertise of the educator, and the length of time that was spent on teaching patients. No consistent patterns of implementation and specific evaluation of its impact were found, although three respective groups of investigators reported signifi cant differences in recurrent hospitalisation rates and mortality rates which were relative to usual care.
Conclusions: Teaching patients appropriate CHF self-care behaviours can significantly improve their health outcomes. Improvements in self-care were demonstrated in seven studies but only three had used validated instruments to measure such changes. This suggests that no firm conclusions can be drawn about changes in self-care practices.

Complexity of management and health outcomes in a prospective cohort study of 573 heart failure patients in Australia : does more equal less?

Aims and objectives : To compare the efficacy of chronic heart failure management programmes (CHF-MPs) according to a scoring algorithm used to quantify the level of applied interventions–the Heart Failure Intervention Score (HF-IS).

Background : The overall efficacy of heart failure programmes has been proven in several meta-analyses. However, the debate continues as to which components are essential in a heart failure programme to improve patient outcomes.

Design : Prospective cohort study of patients participating in heart failure programmes.

Method : Forty-eight of 62 (77%) programmes in Australia participating in a national register of CHF-MPs were evaluated using the HF-IS: derived from a summed and weighted score of each intervention applied by the CHF-MP (27 interventions overall). The CHF-MPs were prospectively categorised as relatively low (HF-IS < 190 – n = 39 programmes & 407 patients) or high (HF-IS ≥ 190 – n = 9 programmes & 166 patients) in complexity. Six-month morbidity and mortality rates in 573 consecutively recruited patients with systolic dysfunction and in New York Heart Association Class II–IV were prospectively examined.

Results : Patients exposed to CHF-MPs with a high HF-IS had a lower rate of unplanned, all-cause hospitalisation (n = 24, 14% vs. n = 102, 25%) compared with CHF-MPs with a low HF-IS within six months. On an adjusted basis, CHF-MPs with a high HF-IS were associated with a reduced risk of unplanned hospitalisation and/or death within six months and remained event-free longer.

Conclusion : High complexity CHF-MPs applying more evidence-based interventions are associated with a higher event-free survival over six months.

Relevance to clinical practice : The HF-IS is an easy-to-use evidence-based tool to assist programme coordinators to improve the quality of their heart failure programme which may also improve patient outcomes.