Skeletal Muscle Changes in Chronic Cardiac Disease and Failure

Prevention and rehabilitation after heart transplantation: A clinical consensus statement of the European Association of Preventive Cardiology, Heart Failure Association of the ESC, and the European Cardio Thoracic Transplant Association, a section of ESOT

Little is known either about either physical activity patterns, or other lifestyle-related prevention measures in heart transplantation (HTx) recipients. The history of HTx started more than 50 years ago but there are still no guidelines or position papers highlighting the features of prevention and rehabilitation after HTx. The aims of this scientific statement are (i) to explain the importance of prevention and rehabilitation after HTx, and (ii) to promote the factors (modifiable/non-modifiable) that should be addressed after HTx to improve patients' physical capacity, quality of life and survival. All HTx team members have their role to play in the care of these patients and multidisciplinary prevention and rehabilitation programmes designed for transplant recipients. HTx recipients are clearly not healthy disease-free subjects yet they also significantly differ from heart failure patients or those who are supported with mechanical circulatory support. Therefore, prevention and rehabilitation after HTx both need to be specifically tailored to this patient population and be multidisciplinary in nature. Prevention and rehabilitation programmes should be initiated early after HTx and continued during the entire post-transplant journey. This clinical consensus.

Physiological determinants of decreased peak leg oxygen uptake in chronic disease: a systematic review and meta-analysis

This systematic review and meta-analysis examined the physiological mechanisms responsible for lower peak exercise leg oxygen uptake (V̇o2) in patients with chronic disease. Studies measuring peak leg V̇o2 (primary outcome) and its physiological determinants during large (cycle) or small muscle mass exercise (single-leg knee extension, SLKE) in patients with chronic disease were included in this meta-analysis. Pooled estimates for each outcome were reported as a weighted mean difference (WMD) between chronic disease and controls. We included 10 studies that measured peak leg V̇o2 in patients with chronic disease (n = 109, mean age: 45 yr; encompassing chronic obstructive pulmonary disease, COPD, heart failure with reduced ejection fraction, HFrEF, or chronic renal failure, RF) and age-matched controls (n = 88). In pooled analysis, peak leg V̇o2 (WMD; -0.23 L/min, 95% CI: -0.32 to -0.13), leg oxygen (O2) delivery (WMD: -0.27 L/min, 95% CI: -0.37 to -0.17), and muscle O2 diffusive conductance (WMD: -5.2 mL/min/mmHg, 95% CI: -7.1 to -3.2) were all significantly lower during cycle and SLKE exercise in chronic disease versus controls. These results highlight that during large and small muscle mass exercise in patients with COPD, HFrEF, or RF, there is no single factor causing peak V̇o2 limitations. Specifically, the lower peak V̇o2 in these pathologies is due to not only the expected impairments in convective O2 delivery but also impairments in muscle oxygen diffusive transport from capillary to mitochondria. Whether impaired muscle O2 transport is caused solely by inactivity or additional muscle pathology remains in question.NEW & NOTEWORTHY Peripheral (skeletal muscle and vasculature) factors contribute significantly to reduced exercise capacity during both large and small muscle mass exercise in chronic diseases such as COPD, HFrEF, or RF and should be important targets of therapy in addition to the primary organs (lungs, heart, and kidneys) affected by disease.

Mitochondrial dysfunction and skeletal muscle atrophy: Causes, mechanisms, and treatment strategies

Skeletal muscle, which accounts for approximately 40% of total body weight, is one of the most dynamic and plastic tissues in the human body and plays a vital role in movement, posture and force production. More than just a component of the locomotor system, skeletal muscle functions as an endocrine organ capable of producing and secreting hundreds of bioactive molecules. Therefore, maintaining healthy skeletal muscles is crucial for supporting overall body health. Various pathological conditions, such as prolonged immobilization, cachexia, aging, drug-induced toxicity, and cardiovascular diseases (CVDs), can disrupt the balance between muscle protein synthesis and degradation, leading to skeletal muscle atrophy. Mitochondrial dysfunction is a major contributing mechanism to skeletal muscle atrophy, as it plays crucial roles in various biological processes, including energy production, metabolic flexibility, maintenance of redox homeostasis, and regulation of apoptosis. In this review, we critically examine recent knowledge regarding the causes of muscle atrophy (disuse, cachexia, aging, etc.) and its contribution to CVDs. Additionally, we highlight the mitochondrial signaling pathways involvement to skeletal muscle atrophy, such as the ubiquitin-proteasome system, autophagy and mitophagy, mitochondrial fission-fusion, and mitochondrial biogenesis. Furthermore, we discuss current strategies, including exercise, mitochondria-targeted antioxidants, in vivo transfection of PGC-1α, and the potential use of mitochondrial transplantation as a possible therapeutic approach.

Efficacy and safety of sodium-glucose cotransporter-2 inhibitors in heart failure with mildly reduced or preserved ejection fraction: an overview of 36 systematic reviews

The recently published randomized trials (RCTs) evaluating the effect of Sodium-glucose cotransporter-2 inhibitors (SGLT2i) in heart failure with mildly reduced (HFmrEF) or preserved ejection fraction (HFpEF) led researchers to perform a plethora of systematic reviews (SRs), often providing contradictory conclusions. This overview of reviews was aimed at summarizing the evidence of these SRs, quantifying the overlap, re-analyzing the evidence in case new studies that were identified, and mapping knowledge gaps. Literature search was conducted through Medline, Scopus, and Cochrane until March 22, 2023. Overall, 36 SRs synthesizing results from 18 RCTs were identified. A substantial overlap was identified among the SRs synthesizing large heart failure or cardiovascular outcome trials (CVOTs). Regarding the composite outcome of cardiovascular (CV) mortality or hospitalization for heart failure (HHF), all authors reported a significant favorable effect. A beneficial effect was also noted for CV and all-cause mortality, albeit not significant. Our meta-analysis demonstrated a significant improvement in health-related quality-of-life (HRQoL) as assessed by the Kansas City Cardiomyopathy Questionnaire Overall Summary Score (KCCQ-OSS, MD = 1.97, p < 0.001), Total Symptom Score (KCCQ-TSS, MD = 2.29, p < 0.001), Clinical Summary Score (KCCQ-CSS, MD = 1.59, p < 0.001), and the 6-min walking distance (MD = 10.78 m, p = 0.032). Regarding safety, SGLT2i were associated with a significantly lower risk of serious adverse events compared to placebo (RR = 0.94, p = 0.002). The use of SGLT2i in HFpEF is both efficient and safe. Further research is required to clarify the impact of SGTL2i on different subphenotypes of HFpEF and the cardiorespiratory capacity of these patients.

Predictors of infraspinatus muscle degeneration in individuals with an isolated supraspinatus tendon tear

OBJECTIVE

Determine the demographic and clinical factors that predict infraspinatus muscle degeneration in individuals with an isolated supraspinatus tendon tear.

MATERIALS AND METHODS

A retrospective analysis was performed using the medical records of patients who had a shoulder MRI interpreted by 1 of 3 fellowship-trained musculoskeletal radiologists since the implementation of a standardized MRI 3 T protocol within our healthcare system. Demographic (e.g., age, sex) and clinical data (e.g., tear size, muscle degeneration, co-morbidities) were collected. Patients with an isolated supraspinatus tendon tear (n = 121) were assigned to one of two groups based on whether any infraspinatus muscle degeneration was present. Logistic regression was used to assess the univariate relationships between infraspinatus muscle degeneration and patient and clinical data, while least absolute shrinkage and selector operator (LASSO) logistic regression was used to assess the multivariable relationship.

RESULTS

Of the patients with an isolated supraspinatus tendon tear, 16.5% had evidence of infraspinatus muscle degeneration. The presence of infraspinatus muscle degeneration was independently associated with cardiovascular disease (P = 0.01), supraspinatus muscle degeneration (P < 0.01), and subscapularis muscle degeneration (P = 0.01). When the multivariable relationship is assessed, supraspinatus muscle degeneration emerged as the only variable of significant importance for detecting infraspinatus muscle degeneration (specificity: 87.1%, sensitivity: 80.0%).

CONCLUSION

Infraspinatus muscle degeneration is not uncommon in individuals with an isolated supraspinatus tear and is most associated with concomitant supraspinatus muscle degeneration. These findings highlight the need for clinicians to specifically assess the status of each rotator cuff muscle, even when the tendon itself is intact.

SGLT-2 inhibitors on prognosis and health-related quality of life in patients with heart failure and preserved ejection fraction: A systematic review and meta-analysis

Background

Heart failure with preserved ejection fraction (HFpEF) is becoming the main subtype of heart failure, but lacks proven effective therapies. Sodium-glucose cotransporter-2 (SGLT-2) inhibitor, a new kind of oral glucose-lowering agent, shows a great effect on improving cardiovascular outcomes. Based on the results of current RCTs, we perform this meta-analysis to illustrate the therapeutic impact of SGLT2i in HFpEF patients.

Methods

We systematically searched the online database and 10 RCTs were involved. The primary outcome was the prognosis outcome of HFpEF patients, including a composite outcome of cardiovascular (CV) death and hospitalization for heart failure (HHF), CV mortality, HHF, and all-cause mortality. Main secondary outcomes included improvement of KCCQ-TSS (Kansas City Cardiomyopathy Questionnaire and total symptom score) and 6-Minute Walk Test (6MWT). All pooled results were calculated by the random-effects model. Statistical heterogeneity was assessed using the chi-squared test and was quantified using the I-squared statistic.

Results

Ten RCTs comprising 10,334 patients were involved in. Incidence of composite outcome was reduced in SGLT-2 inhibitor group compared with placebo (HR: 0.78, 95% CI: 0.69–0.88, p = 0.00). Improvement of KCCQ-TSS was also more pronounced in the SGLT-2 inhibitor group (MD: 2.74, 95% CI: 1.30–4.18, p = 0.00). No statistical difference was observed in 6MWT.

Conclusion

Treating HFpEF patients with SGLT-2 inhibitors is associated with reducing the composite outcome of CV death and HHF and improving health-related quality of life. Further studies with more evidence are in need to confirm this conclusion.

Could SGLT2 Inhibitors Improve Exercise Intolerance in Chronic Heart Failure?

Despite the constant improvement of therapeutical options, heart failure (HF) remains associated with high mortality and morbidity. While new developments in guideline-recommended therapies can prolong survival and postpone HF hospitalizations, impaired exercise capacity remains one of the most debilitating symptoms of HF. Exercise intolerance in HF is multifactorial in origin, as the underlying cardiovascular pathology and reactive changes in skeletal muscle composition and metabolism both contribute. Recently, sodium-related glucose transporter 2 (SGLT2) inhibitors were found to improve cardiovascular outcomes significantly. Whilst much effort has been devoted to untangling the mechanisms responsible for these cardiovascular benefits of SGLT2 inhibitors, little is known about the effect of SGLT2 inhibitors on exercise performance in HF. This review provides an overview of the pathophysiological mechanisms that are responsible for exercise intolerance in HF, elaborates on the potential SGLT2-inhibitor-mediated effects on these phenomena, and provides an up-to-date overview of existing studies on the effect of SGLT2 inhibitors on clinical outcome parameters that are relevant to the assessment of exercise capacity. Finally, current gaps in the evidence and potential future perspectives on the effects of SGLT2 inhibitors on exercise intolerance in chronic HF are discussed.

Skeletal Muscle Contractile Function in Heart Failure With Reduced Ejection Fraction-A Focus on Nitric Oxide

Despite advances over the past few decades, heart failure with reduced ejection fraction (HFrEF) remains not only a mortal but a disabling disease. Indeed, the New York Heart Association classification of HFrEF severity is based on how much exercise a patient can perform. Moreover, exercise capacity-both aerobic exercise performance and muscle power-are intimately linked with survival in patients with HFrEF. This review will highlight the pathologic changes in skeletal muscle in HFrEF that are related to impaired exercise performance. Next, it will discuss the key role that impaired nitric oxide (NO) bioavailability plays in HFrEF skeletal muscle pathology. Lastly, it will discuss intriguing new data suggesting that the inorganic nitrate 'enterosalivary pathway' may be leveraged to increase NO bioavailability via ingestion of inorganic nitrate. This ingestion of inorganic nitrate has several advantages over organic nitrate (e.g., nitroglycerin) and the endogenous nitric oxide synthase pathway. Moreover, inorganic nitrate has been shown to improve exercise performance: both muscle power and aerobic capacity, in some recent small but well-controlled, cross-over studies in patients with HFrEF. Given the critical importance of better exercise performance for the amelioration of disability as well as its links with improved outcomes in patients with HFrEF, further studies of inorganic nitrate as a potential novel treatment is critical.

Contrast Ultrasound Assessment of Skeletal Muscle Recruitable Perfusion after Permanent Left Ventricular Assist Device Implantation: Implications for Functional Recovery

BACKGROUND

In heart failure with reduced ejection fraction (HFrEF), abnormal regulation of skeletal muscle perfusion contributes to reduced exercise tolerance. The aim of this study was to test the hypothesis that improvement in functional status after permanent left ventricular assist device (LVAD) implantation in patients with HFrEF is related to improvement in muscle perfusion during work, which was measured using contrast-enhanced ultrasound (CEUS).

METHODS

CEUS perfusion imaging of calf muscle at rest and during low-intensity plantar flexion exercise (20 W, 0.2 Hz) was performed in patients with HFrEF (n = 22) at baseline and 3 months after placement of permanent LVADs. Parametric analysis of CEUS data was used to quantify muscle microvascular blood flow (MBF), blood volume index, and red blood cell flux rate. For subjects alive at 3 months, comparisons were made between those with New York Heart Association functional class I or II (n = 13) versus III or IV (n = 7) status after LVAD. Subjects were followed for a median of 5.7 years for mortality.

RESULTS

Echocardiographic data before and after LVAD placement and LVAD parameters were similar in subjects classified with New York Heart Association functional class I-II versus functional class III-IV after LVAD. Skeletal muscle MBF at rest and during exercise before LVAD implantation was also similar between groups. After LVAD placement, resting MBF remained similar between groups, but during exercise those with New York Heart Association functional class I or II had greater exercise MBF (111 ± 60 vs 52 ± 38 intensity units/sec, P = .03), MBF reserve (median, 4.45 [3.95 to 6.80] vs 2.22 [0.98 to 3.80]; P = .02), and percentage change in exercise MBF (median, 73% [-28% to 83%] vs -45% [-80% to 26%]; P = .03). During exercise, increases in MBF were attributable to faster microvascular flux rate, with little change in blood volume index, indicating impaired exercise-mediated microvascular recruitment. The only clinical or echocardiographic feature that correlated with post-LVAD exercise MBF was a history of diabetes mellitus. There was a trend toward better survival in patients who demonstrated improvement in muscle exercise MBF after LVAD placement (P = .05).

CONCLUSIONS

CEUS perfusion imaging can quantify peripheral vascular responses to advanced therapies for HFrEF. After LVAD implantation, improvement in functional class is seen in patients with improvements in skeletal muscle exercise perfusion and flux rate, implicating a change in vasoactive substances that control resistance arteriolar tone.

Effects of SGLT-2 inhibitors on health-related quality of life and exercise capacity in heart failure patients with reduced ejection fraction: A systematic review and meta-analysis

OBJECTIVE

Improving health-related quality of life (HRQoL) and exercise capacity is an important goal of treatment in heart failure (HF). However, evidence for the effects of sodium-glucose cotransporter-2 (SGLT-2) inhibitors on the improvement of HRQoL and exercise capacity seems to be conflicted. We performed a systematic review and meta-analysis to evaluate the effects of SGLT-2 inhibitors on HRQL and exercise capacity in patients with heart failure and reduced ejection fraction (HFrEF).

METHODS

All studies (up to March 20, 2021) evaluating the effects of SGLT-2 inhibitors on HRQoL and exercise capacity in patients with HFrEF were initially searched from four electronic search engines: PubMed, Web of Science, Cochrane Library, and SinoMed. All statistical analyses were performed with RevMan 5.4.

RESULTS

We included 9 articles describing 7 trials with 9428 patients. SGLT-2 inhibitors group exhibited significant improvement in HRQoL assessed by Kansas City Cardiomyopathy Questionnaires (KCCQ) (MD: 2.13, 95% CI: 1.11 to 3.14, p < 0.001) and the rate of KCCQ-overall summary score improvement≥5 points (RR 1.15, 95%CI 1.08 to 1.21, P < 0.001) compared with placebo. No significant difference was observed in exercise capacity assessed by 6-min walk test distance between SGLT-2 inhibitors and placebo (MD 24.45, 95%CI -22.82 to 71.72, P = 0.31).

CONCLUSIONS

Our meta-analysis demonstrates that SGLT-2 inhibitors significantly improve HRQoL, and supports the concept that SGLT-2 inhibitors do not significantly improve exercise capacity in patients with HFrEF. Studies with larger sample sizes and longer follow-up duration are needed to determine whether the treatment with SGLT-2 inhibitors may improve exercise ability.

PROSPERO

CRD42021248346.

Treatments for skeletal muscle abnormalities in heart failure: sodium-glucose transporter 2 and ketone bodies

Various skeletal muscle abnormalities are known to occur in heart failure (HF), and are closely associated with exercise intolerance. Particularly, abnormal energy metabolism caused by mitochondrial dysfunction in skeletal muscle is a cause of decreased endurance exercise capacity. However, to date, no specific drug treatment has been established for the skeletal muscle abnormalities and exercise intolerance occurring in HF patients. Sodium-glucose transporter 2 (SGLT2) inhibitors promote glucose excretion by suppressing glucose reabsorption in the renal tubules, which has a hypoglycemic effect independent of insulin secretion. Recently, large clinical trials have demonstrated that treatment with SGLT2 inhibitors suppresses cardiovascular events in patients who have HF with systolic dysfunction. Mechanisms of the therapeutic effects of SGLT2 inhibitors for HF have been suggested to be diuretic, suppression of neurohumoral factor activation, renal protection, and improvement of myocardial metabolism, but has not been clarified to date. SGLT2 inhibitors are known to increase blood ketone bodies. This suggests that they may improve the abnormal skeletal muscle metabolism in HF, i.e., improve fatty acid metabolism, suppress glycolysis, and utilize ketone bodies in mitochondrial energy production. Ultimately, they may improve aerobic metabolism in skeletal muscle, and suppress anaerobic metabolism and improve aerobic exercise capacity at the level of the anaerobic threshold. The potential actions of such SGLT2 inhibitors explain their effectiveness in HF, and may be candidates for new drug treatments aimed at improving exercise intolerance. In this review, we outlined the effects of SGLT2 inhibitors on skeletal muscle metabolism, with a particular focus on ketone metabolism.

Exercise training in heart transplantation

Heart transplantation remains the gold standard in the treatment of end-stage heart failure (HF). Heart transplantation patients present lower exercise capacity due to cardiovascular and musculoskeletal alterations leading thus to poor quality of life and reduction in the ability of daily self-service. Impaired vascular function and diastolic dysfunction cause lower cardiac output while decreased skeletal muscle oxidative fibers, enzymes and capillarity cause arteriovenous oxygen difference, leading thus to decreased peak oxygen uptake in heart transplant recipients. Exercise training improves exercise capacity, cardiac and vascular endothelial function in heart transplant recipients. Pre-rehabilitation regular aerobic or combined exercise is beneficial for patients with end-stage HF awaiting heart transplantation in order to maintain a higher fitness level and reduce complications afterwards like intensive care unit acquired weakness or cardiac cachexia. All hospitalized patients after heart transplantation should be referred to early mobilization of skeletal muscles through kinesiotherapy of the upper and lower limbs and respiratory physiotherapy in order to prevent infections of the respiratory system prior to hospital discharge. Moreover, all heart transplant recipients after hospital discharge who have not already participated in an early cardiac rehabilitation program should be referred to a rehabilitation center by their health care provider. Although high intensity interval training seems to have more benefits than moderate intensity continuous training, especially in stable transplant patients, individualized training based on the abilities and needs of each patient still remains the most appropriate approach. Cardiac rehabilitation appears to be safe in heart transplant patients. However, long-term follow-up data is incomplete and, therefore, further high quality and adequately-powered studies are needed to demonstrate the long-term benefits of exercise training in this population.

Abnormal skeletal muscle blood flow, contractile mechanics and fibre morphology in a rat model of obese-HFpEF

KEY POINTS

Heart failure is characterised by limb and respiratory muscle impairments that limit functional capacity and quality of life. However, compared with heart failure with reduced ejection fraction (HFrEF), skeletal muscle alterations induced by heart failure with preserved ejection fraction (HFpEF) remain poorly explored. Here we report that obese-HFpEF induces multiple skeletal muscle alterations in the rat hindlimb, including impaired muscle mechanics related to shortening velocity, fibre atrophy, capillary loss, and an impaired blood flow response to contractions that implies a perfusive oxygen delivery limitation. We also demonstrate that obese-HFpEF is characterised by diaphragmatic alterations similar to those caused by denervation - atrophy in Type IIb/IIx (fast/glycolytic) fibres and hypertrophy in Type I (slow/oxidative) fibres. These findings extend current knowledge in HFpEF skeletal muscle physiology, potentially underlying exercise intolerance, which may facilitate future therapeutic approaches.

ABSTRACT

Peripheral skeletal muscle and vascular alterations induced by heart failure with preserved ejection fraction (HFpEF) remain poorly identified, with limited therapeutic targets. This study used a cardiometabolic obese-HFpEF rat model to comprehensively phenotype skeletal muscle mechanics, blood flow, microvasculature and fibre atrophy. Lean (n = 8) and obese-HFpEF (n = 8) ZSF1 rats were compared. Skeletal muscles (soleus and diaphragm) were assessed for in vitro contractility (isometric and isotonic properties) alongside indices of fibre-type cross-sectional area, myosin isoform, and capillarity, and estimated muscle PO₂ . In situ extensor digitorum longus (EDL) contractility and femoral blood flow were assessed. HFpEF soleus demonstrated lower absolute maximal force by 22%, fibre atrophy by 24%, a fibre-type shift from I to IIa, and a 17% lower capillary-to-fibre ratio despite increased capillary density (all P < 0.05) with preserved muscle PO₂ (P = 0.115) and isometric specific force (P > 0.05). Soleus isotonic properties (shortening velocity and power) were impaired by up to 17 and 22%, respectively (P < 0.05), while the magnitude of the exercise hyperaemia was attenuated by 73% (P = 0.012) in line with higher muscle fatigue by 26% (P = 0.079). Diaphragm alterations (P < 0.05) included Type IIx fibre atrophy despite Type I/IIa fibre hypertrophy, with increased indices of capillarity alongside preserved contractile properties during isometric, isotonic, and cyclical contractions. In conclusion, obese-HFpEF rats demonstrated blunted skeletal muscle blood flow during contractions in parallel to microvascular structural remodelling, fibre atrophy, and isotonic contractile dysfunction in the locomotor muscles. In contrast, diaphragm phenotype remained well preserved. This study identifies numerous muscle-specific impairments that could exacerbate exercise intolerance in obese-HFpEF.

Mechanisms underlying the pathophysiology of heart failure with preserved ejection fraction: the tip of the iceberg

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome with a complex aetiology often associated with several comorbidities, such as left ventricle pressure overload, diabetes mellitus, obesity, and kidney disease. Its pathophysiology remains obscure mainly due to the complex phenotype induced by all these associated comorbidities and to the scarcity of animal models that adequately mimic HFpEF. Increased oxidative stress, inflammation, and endothelial dysfunction are currently accepted as key players in HFpEF pathophysiology. However, we have just started to unveil HFpEF complexity and the role of calcium handling, energetic metabolism, and mitochondrial function remain to clarify. Indeed, the enlightenment of such cellular and molecular mechanisms represents an opportunity to develop novel therapeutic approaches and thus to improve HFpEF treatment options. In the last decades, the number of research groups dedicated to studying HFpEF has increased, denoting the importance and the magnitude achieved by this syndrome. In the current technological and web world, the amount of information is overwhelming, driving us not only to compile the most relevant information about the theme but also to explore beyond the tip of the iceberg. Thus, this review aims to encompass the most recent knowledge related to HFpEF or HFpEF-associated comorbidities, focusing mainly on myocardial metabolism, oxidative stress, and energetic pathways.

Unique Transcriptome Signature Distinguishes Patients With Heart Failure With Myopathy

Background People with chronic heart failure (CHF) experience severe skeletal muscle dysfunction, characterized by mitochondrial abnormalities, which exacerbates the primary symptom of exercise intolerance. However, the molecular triggers and characteristics underlying mitochondrial abnormalities caused by CHF remain poorly understood. Methods and Results We recruited 28 patients with CHF caused by reduced ejection fraction and 9 controls. We simultaneously biopsied skeletal muscle from the pectoralis major in the upper limb and from the vastus lateralis in the lower limb. We phenotyped mitochondrial function in permeabilized myofibers from both sites and followed this by complete RNA sequencing to identify novel molecular abnormalities in CHF skeletal muscle. Patients with CHF presented with upper and lower limb skeletal muscle impairments to mitochondrial function that were of a similar deficit and indicative of a myopathy. Mitochondrial abnormalities were strongly correlated to symptoms. Further RNA sequencing revealed a unique transcriptome signature in CHF skeletal muscle characterized by a novel triad of differentially expressed genes related to deficits in energy metabolism including adenosine monophosphate deaminase 3, pyridine nucleotide-disulphide oxidoreductase domain 2, and lactate dehydrogenase C. Conclusions Our data suggest an upper and lower limb metabolic myopathy that is characterized by a unique transcriptome signature in skeletal muscle of humans with CHF.

Impact of Incident Heart Failure on Body Composition Over Time in the Health, Aging, and Body Composition Study Population

BACKGROUND

Prevalence of heart failure (HF) increases significantly with age, coinciding with age-related changes in body composition that are common and consequential. Still, body composition is rarely factored in routine HF care.

METHODS AND RESULTS

The Health, Aging, and Body Composition study is a prospective cohort study of nondisabled adults. Using yearly dual-energy x-ray absorptiometry, body composition was assessed in the Health, Aging, and Body Composition study over 6 years, comparing those who developed incident HF versus those who did not. Among 2815 Health, Aging, and Body Composition participants (48.5% men; 59.6% whites; mean age, 73.6±2.9 years), 111 developed incident HF over the 6-year study period. At entry into the Health, Aging, and Body Composition study, men and women who later developed HF had higher total body mass when compared with those versus those who did not develop HF (men, 80.9±10 versus 78.6±12.9 kg, P=0.05; women, 72.7±15.0 versus 68.2±14.2 kg, P=0.01, respectively). However, after developing HF, loss of total lean body mass was disproportionate; men with HF lost 654.6 versus 391.4 g/y in non-HF participants, P=0.02. Loss of appendicular lean mass was also greater with HF (-419.9 versus -318.2 g/y; P=0.02), even after accounting for total weight change. Among women with HF, loss of total and appendicular lean mass were also greater than in non-HF participants but not to the extent seen among men.

CONCLUSIONS

Incident HF in older adults was associated with disproportionate loss of lean mass, particularly among men. Prognostic implications are significant, with key sex-specific inferences on physical function, frailty, disability, and pharmacodynamics that all merit further investigation.