Heart failure with preserved ejection fraction: pathophysiology and emerging therapies

FFAR4 regulates cardiac oxylipin balance to promote inflammation resolution in HFpEF secondary to metabolic syndrome

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome, but a predominant subset of HFpEF patients has metabolic syndrome (MetS). Mechanistically, systemic, nonresolving inflammation associated with MetS might drive HFpEF remodeling. Free fatty acid receptor 4 (Ffar4) is a GPCR for long-chain fatty acids that attenuates metabolic dysfunction and resolves inflammation. Therefore, we hypothesized that Ffar4 would attenuate remodeling in HFpEF secondary to MetS (HFpEF-MetS). To test this hypothesis, mice with systemic deletion of Ffar4 (Ffar4KO) were fed a high-fat/high-sucrose diet with L-NAME in their water to induce HFpEF-MetS. In male Ffar4KO mice, this HFpEF-MetS diet induced similar metabolic deficits but worsened diastolic function and microvascular rarefaction relative to WT mice. Conversely, in female Ffar4KO mice, the diet produced greater obesity but no worsened ventricular remodeling relative to WT mice. In Ffar4KO males, MetS altered the balance of inflammatory oxylipins systemically in HDL and in the heart, decreasing the eicosapentaenoic acid-derived, proresolving oxylipin 18-hydroxyeicosapentaenoic acid (18-HEPE), while increasing the arachidonic acid-derived, proinflammatory oxylipin 12-hydroxyeicosatetraenoic acid (12-HETE). This increased 12-HETE/18-HEPE ratio reflected a more proinflammatory state both systemically and in the heart in male Ffar4KO mice and was associated with increased macrophage numbers in the heart, which in turn correlated with worsened ventricular remodeling. In summary, our data suggest that Ffar4 controls the proinflammatory/proresolving oxylipin balance systemically and in the heart to resolve inflammation and attenuate HFpEF remodeling.

Electrocardiogram as a Tool to Predict Diastolic Dysfunction in the Early Hypertensive Patients and its Comparison in Males and Females

Objectives:

Heart failure with preserved ejection fraction continues to be a major healthcare challenge. Assessment of diastolic dysfunction (DD) is an integral part of the routine cardiologic examination, however little is known about ECG changes in diastolic dysfunction. several resting ECG parameters have been investigated to predict left ventricular diastolic dysfunction (LVDD). The study aims to assess diastolic dysfunction in recently diagnosed hypertensive patients by echocardiography and to find the value of ECG-derived parameters in predicting diastolic dysfunction.

Materials and Methods:

One hundred and fifty hypertensive patients of less than 1-year duration were divided into two groups based on the presence or absence of diastolic dysfunction. ECG parameters such as P wave dispersion, QT and QTc interval, ventricular activation time, Tend P, Tend Q were analyzed in all patients, and correlation was done with echo parameters to assess diastolic dysfunction in both males and females.

Results:

In both men and women a significant correlation was found between p wave dispersion, ventricular activation time, Corrected QT interval, TendP, and, Tend Q in ECG with diastolic dysfunction on bivariate regression analysis. Multivariate regression analysis showed that p wave dispersion had a greater correlation with diastolic dysfunction when compared with other ECG parameters (r=0.88, R2=0.78).

Conclusion:

Analysis of certain ECG parameters especially p wave dispersion is of great value in predicting diastolic dysfunction in both men and women.

Profile of urinary amino acids and their post-translational modifications (PTM) including advanced glycation end-products (AGEs) of lysine, arginine and cysteine in lean and obese ZSF1 rats

Heart failure with preserved ejection fraction (HFpEF) is associated with high mortality and has an increasing prevalence associated with the demographic change and limited therapeutic options. Underlying mechanisms are largely elusive and need to be explored to identify specific biomarkers and new targets, which mirror disease progression and intervention success. Obese ZSF1 (O-ZSF1) rats are a useful animal model, as they spontaneously develop hypertension, hyperlipidemia and glucose intolerance and finally HFpEF. The urinary profile of amino acids and their metabolites of post-translational modifications (PTM), including the advanced glycation end-products (AGEs) of lysine, arginine and cysteine, are poorly investigated in HFpEF and ZSF1 rats. The aim of the present study was to characterize the status of free amino acids and their metabolites of PTM and glycation in lean ZSF1 (L-ZSF1) and O-ZSF1 rats in urine aiming to find possible effects of glucose on the excretion of native and modified amino acids. In the urine of twelve L-ZSF1 and twelve O-ZFS1 rats collected at the age of 20 weeks, we measured the concentration of native and modified amino acids by reliable previously validated stable-isotope dilution gas chromatography-mass spectrometry (GC–MS) approaches. Serum glucose was 1.39-fold higher in the O-ZSF1 rats, while urinary creatinine concentration was 2.5-fold lower in the O-ZSF1 rats. We observed many differences in urinary amino acids excretion between L-ZSF1 and O-ZSF1 rats. The creatinine-corrected homoarginine excretion was twofold lower in the O-ZSF1 rats. We also observed distinct associations between the concentrations of serum glucose and urinary amino acids including their PTM and AGE metabolites in the L-ZSF1 and O-ZSF1 rats. Our study shows that PTM metabolites and AGEs are consistently lower in the L-ZSF1 than in the O-ZSF1 rats. Serum malondialdehyde (MDA) concentration was higher in the O-ZSF1 rats. These results suggest that hyperglycemia, hyperlipidemia and elevated oxidative stress in the O-ZSF1 rats favor PTM methylation of arginine and lysine and the glycation of lysine and cysteine. The area under the receiver operation characteristic (ROC) curve values were 0.996 for serum glucose, 0.951 for urinary creatinine, 0.939 for serum MDA, 0.885 for N^ε-carboxyethyl-lysine, 0.830 for carboxyethyl-cysteine, and 0.792 for monomethyl-lysine. Non-invasive measurement of methylation and glycation products of arginine, lysine and cysteine residues in proteins in urine of L-ZSF1 and O-ZSF1 rats may be useful in studying pathophysiology and pharmacology of HFpEF.

Imaging cAMP nanodomains in the heart

3′-5′-cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that modulates multiple cellular functions. It is now well established that cAMP can mediate a plethora of functional effects via a complex system of local regulatory mechanisms that result in compartmentalized signalling. The use of fluorescent probes to monitor cAMP in intact, living cells have been instrumental in furthering our appreciation of this ancestral and ubiquitous pathway and unexpected details of the nano-architecture of the cAMP signalling network are starting to emerge. Recent evidence shows that sympathetic control of cardiac contraction and relaxation is achieved via generation of multiple, distinct pools of cAMP that lead to differential phosphorylation of target proteins localized only tens of nanometres apart. The specific local control at these nanodomains is enabled by a distinct signalosome where effectors, targets, and regulators of the cAMP signal are clustered. In this review, we focus on recent advances using targeted fluorescent reporters for cAMP and how they have contributed to our current understanding of nanodomain cAMP signalling in the heart. We briefly discuss how this information can be exploited to design novel therapies and we highlight some of the questions that remain unanswered.

A concise review of recent advances in anti-heart failure targets and its small molecules inhibitors in recent years

Heart failure is a disease with high mortality and the risk of heart failure increases in magnitude with age. The patients of heart failure is increasing year by year. Hence, Pharmaceutical researchers have to develop new drugs with better pharmacological effects to coping with this phenomenon. In this article, we reviewed the small molecule compounds for heart failure that have been marketed in recent years or are promising to enter clinical research. We also reviewed the SAR (structure activity relationship) of these molecules, such as renin inhibitors, ROMK inhibitors, a kind of new diuretics, and some dual-targets inhibitors. These small molecules proven to be beneficial effect on heart failure patients. Which may provide ideas for the design of novel anti-heart failure therapeutic drugs.

Cardiac wall mechanics analysis in hypertension-induced heart failure rats with preserved ejection fraction

Although cardiac wall mechanics is of importance for understanding heart failure with preserved ejection fraction (HFpEF), there is a lack of relevant mechanics studies. The aim of this study was to analyze the changes in stress and strain in the left ventricle (LV) in hypertension-induced HFpEF rats. Based on experimental measurements in DSS rats fed with high-salt (HS) and low-salt (LS) diets, LV stress and strain were computed throughout the cardiac cycle using Continuity software. HS-feeding increased myofiber stress and strain along both the transmural and longitudinal directions at the end-diastolic state but resulted in a lower absolute value of strain and relatively unchanged stress at the end-systolic state. Moreover, the end-diastolic stress and strain decreased with increasing radial position from the endocardial towards the epicardial walls despite negligible changes along the longitudinal direction. The changes in LV wall mechanics characterized the elevated diastolic LV stiffness and slow LV relaxation in HS-fed rats of HFpEF. These findings denote that a vicious cycle of increased stress and strain and diastolic dysfunction can prompt the development of HFpEF.

Cardiac structure and function after revascularization versus medical therapy for renal artery stenosis: the ASTRAL heart echocardiographic sub-study

Background

The ASTRAL trial showed no difference in clinical outcomes between medical therapy and revascularization for atherosclerotic renal vascular disease (ARVD). Here we report a sub-study using echocardiography to assess differences in cardiac structure and function at 12 months.

Methods

ASTRAL patients from 7 participating centres underwent echocardiography at baseline and 12 months after randomisation. Changes in left ventricular ejection fraction (LVEF), left ventricular mass (LVM), left atrial diameter (LAD), aortic root diameter (AoRD), E:A, and E deceleration time (EDT) were compared between study arms. Analyses were performed using t-tests and multivariate linear regression.

Results

Ninety two patients were included (50 medical versus 42 revascularization). There was no difference between arms in any baseline echocardiographic parameter. Comparisons of longitudinal changes in echocardiographic measurements were: δLVEF medical 0.8 ± 8.7% versus revascularization − 2.8 ± 6.8% (p = 0.05), δLVM − 2.9 ± 33 versus − 1.7 ± 39 g (p = 0.9), δLAD 0.1 ± 0.4 versus 0.01 ± 0.5 cm (p = 0.3), δAoRD 0.002 ± 0.3 versus 0.06 ± 0.3 cm (p = 0.4), δE:A − 0.0005 ± 0.6 versus 0.03 ± 0.7 (p = 0.8), δEDT − 1.1 ± 55.5 versus − 9.0 ± 70.2 ms (p = 0.6). In multivariate models, there were no differences between treatment groups for any parameter at 12 months. Likewise, change in blood pressure did not differ between arms (mean δsystolic blood pressure medical 0 mmHg [range − 56 to + 54], revascularization − 3 mmHg [− 61 to + 59], p = 0.60).

Conclusions

This sub-study did not show any significant differences in cardiac structure and function accompanying renal revascularization in ASTRAL. Limitations include the small sample size, the relative insensitivity of echocardiography, and the fact that a large proportion of ASTRAL patient population had only modest renal artery stenosis as described in the main study.

ω3-Polyunsaturated fatty acids for heart failure: Effects of dose on efficacy and novel signaling through free fatty acid receptor 4

Heart failure (HF) affects 5.7 million in the U.S., and despite well-established pharmacologic therapy, the 5-year mortality rate remains near 50%. Furthermore, the mortality rate for HF has not declined in years, highlighting the need for new therapeutic options. Omega-3 polyunsaturated fatty acids (ω3-PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are important regulators of cardiovascular health. However, questions of efficacy and mechanism of action have made the use of ω3-PUFAs in all cardiovascular disease (CVD) controversial. Here, we review recent studies in animal models of HF indicating that ω3-PUFAs, particularly EPA, are cardioprotective, with the results indicating a threshold for efficacy. We also examine clinical studies suggesting that ω3-PUFAs improve outcomes in patients with HF. Due to the relatively small number of clinical studies of ω3-PUFAs in HF, we discuss EPA concentration-dependency on outcomes in clinical trials of CVD to gain insight into the perceived questionable efficacy of ω3-PUFAs clinically, with the results again indicating a threshold for efficacy. Ultimately, we suggest that the main failing of ω3-PUFAs in clinical trials might be a failure to reach a therapeutically effective concentration. We also examine mechanistic studies suggesting that ω3-PUFAs signal through free fatty acid receptor 4 (Ffar4), a G-protein coupled receptor (GPR) for long-chain fatty acids (FA), thereby identifying an entirely novel mechanism of action for ω3-PUFA mediated cardioprotection. Finally, based on mechanistic animal studies suggesting that EPA prevents interstitial fibrosis and diastolic dysfunction, we speculate about a potential benefit for EPA-Ffar4 signaling in heart failure preserved with ejection fraction.

EPA, not DHA, prevents fibrosis in pressure overload-induced heart failure: potential role of free fatty acid receptor 4

Heart failure with preserved ejection fraction (HFpEF) is half of all HF, but standard HF therapies are ineffective. Diastolic dysfunction, often secondary to interstitial fibrosis, is common in HFpEF. Previously, we found that supra-physiologic levels of ω3-PUFAs produced by 12 weeks of ω3-dietary supplementation prevented fibrosis and contractile dysfunction following pressure overload [transverse aortic constriction (TAC)], a model that resembles aspects of remodeling in HFpEF. This raised several questions regarding ω3-concentration-dependent cardioprotection, the specific role of EPA and DHA, and the relationship between prevention of fibrosis and contractile dysfunction. To achieve more clinically relevant ω3-levels and test individual ω3-PUFAs, we shortened the ω3-diet regimen and used EPA- and DHA-specific diets to examine remodeling following TAC. The shorter diet regimen produced ω3-PUFA levels closer to Western clinics. Further, EPA, but not DHA, prevented fibrosis following TAC. However, neither ω3-PUFA prevented contractile dysfunction, perhaps due to reduced uptake of ω3-PUFA. Interestingly, EPA did not accumulate in cardiac fibroblasts. However, FFA receptor 4, a G protein-coupled receptor for ω3-PUFAs, was sufficient and required to block transforming growth factor β1-fibrotic signaling in cultured cardiac fibroblasts, suggesting a novel mechanism for EPA. In summary, EPA-mediated prevention of fibrosis could represent a novel therapy for HFpEF.

Comparison of 5-Year Outcomes After Coronary Artery Bypass Grafting in Heart Failure Patients With Versus Without Preserved Left Ventricular Ejection Fraction (from the CREDO-Kyoto CABG Registry Cohort-2)

Heart failure (HF) with reduced left ventricular (LV) ejection fraction (HFrEF) is regarded as an independent risk factor for poor outcomes after coronary artery bypass grafting (CABG). However, the impact of HF with preserved EF (HFpEF) still has been unclear. We identified 1,877 patients who received isolated CABG of 15,939 patients who underwent first coronary revascularization enrolled in the CREDO-Kyoto (Coronary REvascularization Demonstrating Outcome Study in Kyoto) Registry Cohort-2. Of them, 1,489 patients had normal LV function (LVEF >50% without a history of HF; Normal group), 236 had HFrEF (LVEF ≤50% with HF), and 152 had HFpEF (LVEF >50% with HF). Preoperative LVEF was the lowest in the HFrEF group (62 ± 12%, 36 ± 9%, and 61 ± 7% for the Normal, HFrEF, and HFpEF groups, respectively; p <0.001). Unadjusted 30-day mortality rate was the highest in the HFrEF group (0.5%, 3.0%, and 0.7%; p = 0.003). However, cumulative incidences of all-cause death at 5-year was the highest in the HFpEF group (14%, 27%, and 32%, respectively; p <0.001). After adjusting confounders, the risk of all-cause death in the HFpEF group was greater than the Normal group (hazard ratio [HR] 1.42; 95% confidence interval [CI] 1.02 to 1.97; p = 0.04). The risk of all-cause death was not different between the HFpEF and the HFrEF groups (HR 0.88; 95% CI 0.61 to 1.29; p = 0.52). In addition, the risks of cardiac death and sudden death in the HFpEF group were greater than the Normal group (HR 2.14, 95% CI 1.32 to 3.49, p = 0.002; and HR 3.60, 95% CI 1.55 to 8.36, p = 0.003, respectively), and the risks of those end points were not different between the HFrEF and the HFpEF groups. Despite low 30-day mortality rate after CABG in patients with HFpEF, HFpEF was associated with high risks of long-term death and cardiovascular events. Patients with HFpEF, as well as HFrEF, should be carefully operated and followed up.

Effects of renin-angiotensin-aldosterone system inhibitors on mortality, hospitalization, and diastolic function in patients with HFpEF. A meta-analysis of 13 randomized controlled trials

AIM

The purpose of this meta-analysis was to evaluate the effects of renin-angiotensin-aldosterone system (RAAS) inhibitors on mortality, hospitalization, diastolic function, and exercise capacity in heart failure with preserved ejection fraction (HFpEF).

METHODS

Thirteen randomized controlled trials (RCTs), totaling 12,532 patients with HFpEF, were selected. All-cause and cardiovascular mortality, all-cause and heart failure-related hospitalization, diastolic function, and the 6-min walk distance were assessed. The risk ratios (RR) of the dichotomous data, weighted mean difference (WMD) of continuous data, and 95 % confidence intervals (CI) were calculated to assess the effects of RAAS inhibitors.

RESULTS

RAAS inhibitors significantly decreased heart failure-related hospitalization (RR 0.89; 95 % CI 0.82-0.97; p = 0.01) and improved the diastolic function, as reflected in a reduced E/e' index (MD -1.38; 95 % CI -2.01 to -0.74; p < 0.0001). However, there were no beneficial effects on all-cause cardiovascular mortality and all-cause hospitalization. Other diastolic parameters had few changes compared with the controls. The 6-min walk distance was not improved by the use of RAAS inhibitors.

CONCLUSION

In patients with HFpEF, RAAS inhibitors decreased heart-failure hospitalization and the E/e' index without affecting mortality, all-cause hospitalization, other diastolic function parameters, and the 6-min walk distance.

Incorporating patients with chronic heart failure into outpatient cardiac rehabilitation: practical recommendations for exercise and self-care counseling-a clinical review

PURPOSE

A recent policy change from the Centers for Medicare and Medicaid Services includes coverage of cardiac rehabilitation (CR) for patients with chronic heart failure (CHF) with reduced ejection fraction. This article provides a framework by which CR programs can incorporate disease-specific services for patients with CHF who participate in CR.

DISCUSSION

Cardiac rehabilitation should include self-care counseling that targets improved education and skill development (eg, medication compliance, monitoring/management of body weight). Various tools are available for assessing exercise tolerance (eg, stress test with gas exchange and 6-minute walk), health-related quality of life, and other outcome-related parameters. Exercise should be prescribed in a manner that progressively increases intensity, duration, and frequency, to a volume of exercise equivalent to 3 to 7 metabolic equivalent task (MET)-hr per week. The benefits of exercise training are limited by patient adherence; therefore, CR providers need to identify the adherence challenges unique to each patient and address each accordingly. To optimize the referral of patients with CHF to CR, program staff should develop strategies to raise both health care provider and patient awareness about the benefits of CR, as well as work collaboratively to set up system-based approaches to CR referral.

CONCLUSIONS

The referral of patients with CHF to CR will increase in 2014 and beyond, due partly to a policy change from the Centers for Medicare and Medicaid Services that allows coverage for CR. These patients should be integrated into existing programs, with the intent of providing both standard CR services and CHF-specific education and disease management activities that target improved outcomes.

New strategies for heart failure with preserved ejection fraction: the importance of targeted therapies for heart failure phenotypes

The management of heart failure with reduced ejection fraction (HF-REF) has improved significantly over the last two decades. In contrast, little or no progress has been made in identifying evidence-based, effective treatments for heart failure with preserved ejection fraction (HF-PEF). Despite the high prevalence, mortality, and cost of HF-PEF, large phase III international clinical trials investigating interventions to improve outcomes in HF-PEF have yielded disappointing results. Therefore, treatment of HF-PEF remains largely empiric, and almost no acknowledged standards exist. There is no single explanation for the negative results of past HF-PEF trials. Potential contributors include an incomplete understanding of HF-PEF pathophysiology, the heterogeneity of the patient population, inadequate diagnostic criteria, recruitment of patients without true heart failure or at early stages of the syndrome, poor matching of therapeutic mechanisms and primary pathophysiological processes, suboptimal study designs, or inadequate statistical power. Many novel agents are in various stages of research and development for potential use in patients with HF-PEF. To maximize the likelihood of identifying effective therapeutics for HF-PEF, lessons learned from the past decade of research should be applied to the design, conduct, and interpretation of future trials. This paper represents a synthesis of a workshop held in Bergamo, Italy, and it examines new and emerging therapies in the context of specific, targeted HF-PEF phenotypes where positive clinical benefit may be detected in clinical trials. Specific considerations related to patient and endpoint selection for future clinical trials design are also discussed.

The burden of preserved ejection fraction heart failure in a real-world Swedish patient population

OBJECTIVES

To evaluate resource use and associated costs in patients with a diagnosis of heart failure with preserved ejection fraction (HF-PEF) in Sweden.

METHODS

This retrospective study identified real-world patients with an ICD-10 diagnosis code for heart failure (I50) for the period between July 1, 2005 and December 31, 2006 from electronic medical records of primary care centers in Uppsala County Council, and in the Swedish patient registry data. Patients were categorized as having HF-PEF (left ventricle ejection fraction [LVEF] > 50%) during the index period. The study assessed medication utilization, outpatient visits, hospitalizations, and associated healthcare costs, as well as the incidence rates and time to all-cause and heart failure mortality following the index period.

RESULTS

The study included 137 HF-PEF patients with a mean age of 77.1 (SD = 9.1) years. Over 50% of HF-PEF patients were female and hypertensive. Nearly all patients received ≥ 1 medication post-index. Patients had an average of 1.5 heart failure related hospitalizations per follow-up year. The average annual per patient cost for the management of a HF-PEF patient was found in Sweden to be Swedish Krona (SEK) 108,246 (EURO [EUR] 11,344). Hospitalizations contributed to more than 80% of the total cost. All-cause mortality over the 18-month study period was 25.5%, and more than 50% of these deaths occurred within 1 year of index.

LIMITATIONS

Due to the limitations of registry data, it is not possible to confirm the HF diagnosis, and therefore the accuracy of registry records must be assumed. Other factors such as short follow-up time, the study-mandated LVEF assessment, and a lack of drug duration data may also have an impact on the study results.

CONCLUSIONS

All-cause mortality was high in the HF-PEF population, with more than half of patients dying within 1 year of study follow-up. Study results also indicate that 60% of HF-PEF patients have ≥ 1 hospitalization during follow-up. Hospitalizations, especially heart failure related admissions, represent a substantial proportion of the total healthcare burden of patients with HF-PEF in Sweden.

Diagnosing heart failure with preserved ejection fraction

INTRODUCTION

Heart failure with preserved ejection fraction (HFPEF) is a common syndrome, accounting for about 50% of all patients with heart failure (HF). Morbidity and mortality are similar to patients with HF with reduced ejection fraction (HFREF), yet no effective treatment has been identified in randomized clinical trials.

AREAS COVERED

This article provides an overview of the available literature regarding diagnosing established HFPEF and potential new therapeutic targets for the early diagnosis of HFPEF. Vascular dysfunction, ventricular-arterial coupling, oxidative stress, extracellular matrix regulation, chronotropic incompetence, pulmonary hypertension, exercise testing and biomarkers were taken into consideration next to conventional measurements of diastolic dysfunction.

EXPERT OPINION

Measuring diastolic dysfunction in HFPEF is considered important in many patients. Nevertheless, today we know that other causes besides diastolic dysfunction are also involved in the pathophysiology of many HFPEF patients and need to be investigated in order to make a correct diagnosis. Therefore, further research is required to allow better and more specific diagnostic and treatment options to reduce the morbidity and mortality for this ever-expanding HF population.

Effects of inspiratory muscle training in patients with heart failure with preserved ejection fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is remarkably common in elderly people with highly prevalent comorbid conditions. Despite its increasing in prevalence, there is no evidence-based effective therapy for HFpEF. We sought to evaluate whether inspiratory muscle training (IMT) improves exercise capacity, as well as left ventricular diastolic function, biomarker profile and quality of life (QoL) in patients with advanced HFpEF and nonreduced maximal inspiratory pressure (MIP).

DESIGN AND METHODS

A total of 26 patients with HFpEF (median (interquartile range) age, peak exercise oxygen uptake (peak VO2) and left ventricular ejection fraction of 73 years (66-76), 10 ml/min/kg (7.6-10.5) and 72% (65-77), respectively) were randomized to receive a 12-week programme of IMT plus standard care vs. standard care alone. The primary endpoint of the study was evaluated by positive changes in cardiopulmonary exercise parameters and distance walked in 6 minutes (6MWT). Secondary endpoints were changes in QoL, echocardiogram parameters of diastolic function, and prognostic biomarkers.

RESULTS

The IMT group improved significantly their MIP (p < 0.001), peak VO2 (p < 0.001), exercise oxygen uptake at anaerobic threshold (p = 0.001), ventilatory efficiency (p = 0.007), metabolic equivalents (p < 0,001), 6MWT (p < 0.001), and QoL (p = 0.037) as compared to the control group. No changes on diastolic function parameters or biomarkers levels were observed between both groups.

CONCLUSIONS

In HFpEF patients with low aerobic capacity and non-reduced MIP, IMT was associated with marked improvement in exercise capacity and QoL.

Effect of endurance exercise training on endothelial function and arterial stiffness in older patients with heart failure and preserved ejection fraction: a randomized, controlled, single-blind trial

OBJECTIVES

The study sought to evaluate the effects of endurance exercise training (ET) on endothelial-dependent flow-mediated arterial dilation (FMD) and carotid artery stiffness, and their potential contributions to the training-related increase in peak exercise oxygen consumption (Vo2) in older patients with heart failure with preserved ejection fraction (HFPEF).

BACKGROUND

Elderly HFPEF patients have severely reduced peak Vo2, which improves with ET, however, the mechanisms of this improvement are unclear. FMD and arterial distensibility are critical components of the exercise response and are reduced with aging. However, it is unknown whether these improve with ET in elderly HFPEF or contribute to the training-related improvement in peak Vo2.

METHODS

A total of 63 HFPEF patients (age 70 ± 7 years) were randomized to 16 weeks of ET (walking, arm and leg ergometry, n = 32) or attention control (CT) (n = 31). Peak Vo2, brachial artery FMD in response to cuff ischemia, carotid artery distensibility by high-resolution ultrasound, left ventricular function, and quality of life were measured at baseline and follow-up.

RESULTS

ET increased peak Vo2 (ET: 15.8 ± 3.3 ml/kg/min vs. CT: 13.8 ± 3.1 ml/kg/min, p = 0.0001) and quality of life. However, brachial artery FMD (ET: 3.8 ± 3.0% vs. CT: 4.3 ± 3.5%, p = 0.88), and carotid arterial distensibility (ET: 0.97 ± 0.56 vs. CT: 1.07 ± 0.34 × 10(-3) mm·mm Hg(-2); p = 0.65) were unchanged. Resting left ventricular systolic and diastolic function were unchanged by ET.

CONCLUSIONS

In elderly HFPEF patients, 16 weeks of ET improved peak Vo2 without altering endothelial function or arterial stiffness. This suggests that other mechanisms, such as enhanced skeletal muscle perfusion and/or oxygen utilization, may be responsible for the ET-mediated increase in peak Vo2 in older HFPEF patients. (Prospective Aerobic Reconditioning Intervention Study [PARIS]; NCT01113840).

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Use of continuous flow ventricular assist devices in patients with heart failure and a normal ejection fraction: a computer-simulation study

OBJECTIVES

Continuous flow left ventricular assist devices are used in end-stage systolic heart failure. However, about one half of the patients with heart failure exhibit diastolic dysfunction with a normal ejection fraction. In the present study, the possible hemodynamic consequences of continuous flow left ventricular assist devices use for these patients were investigated.

METHODS

A previously developed cardiovascular model was modified to reproduce the peculiar hemodynamics of heart failure with a normal ejection fraction. The model was based on and validated with patient data derived from the published data. A continuous flow left ventricular assist device model was included and the hemodynamic effects of pump support evaluated at rest and during exercise.

RESULTS

The model accurately reproduced the published data both at rest and during exercise, leading to simulated hemodynamic values within the standard deviations of patient variability. At rest, pump support decreased the end-diastolic left ventricular pressure (6 vs 15 mm Hg) and volume (88 vs 135 mL). During exercise, maximal pump support substantially unloaded the left ventricle (end-diastolic pressure, 14 vs 35 mm Hg; volume, 133 vs 158 mL) and the pulmonary venous circulation (left atrial pressure, 12 vs 24 mm Hg) and resulted in a slight increase in cardiac output (11.7 vs 9.9 L/min).

CONCLUSIONS

The simulation results suggested that continuous flow left ventricular assist devices improve the hemodynamics in patients with heart failure and a normal ejection fraction. For an optimal use of continuous flow left ventricular assist devices, low speeds should be maintained at rest, to avoid suction. However, during physical activity, higher speeds are needed to prevent an abnormal increase in the ventricular filling pressures typical of patients with heart failure and a normal ejection fraction.

Diastolic Heart Failure

Multiple recent epidemiologic studies have highlighted the importance of diastolic heart failure (DHF) as a public health problem. Approximately half of patients presenting with symptomatic heart failure (HF) have DHF and they suffer from morbidity and mortality comparable to those with systolic HF. Our understanding of the pathophysiology of DHF has evolved rapidly over the last decade, and the associated echo-Doppler findings that assist with its diagnosis are greatly refined. Recently, there has been increased recognition of the role of diastolic dysfunction and DHF in the care of critically ill patients, including those admitted to noncardiac units. The purpose of this review is to provide an up-to-date summary of the concepts of the pathophysiology of DHF. In addition, we provide an overview of the diagnostic approaches, prognostic identifiers, and associated comorbidities that make DHF more resistant to manage with a focus of the patients admitted to the intensive care unit. The current approach to managing patients with DHF is also reviewed.

Exercise training in older patients with heart failure and preserved ejection fraction: a randomized, controlled, single-blind trial

BACKGROUND

Heart failure (HF) with preserved left ventricular ejection fraction (HFPEF) is the most common form of HF in the older population. Exercise intolerance is the primary chronic symptom in patients with HFPEF and is a strong determinant of their reduced quality of life (QOL). Exercise training (ET) improves exercise intolerance and QOL in patients with HF with reduced ejection fraction (EF). However, the effect of ET in HFPEF has not been examined in a randomized controlled trial.

METHODS AND RESULTS

This 16-week investigation was a randomized, attention-controlled, single-blind study of medically supervised ET (3 days per week) on exercise intolerance and QOL in 53 elderly patients (mean age, 70±6 years; range, 60 to 82 years; women, 46) with isolated HFPEF (EF ≥50% and no significant coronary, valvular, or pulmonary disease). Attention controls received biweekly follow-up telephone calls. Forty-six patients completed the study (24 ET, 22 controls). Attendance at exercise sessions in the ET group was excellent (88%; range, 64% to 100%). There were no trial-related adverse events. The primary outcome of peak exercise oxygen uptake increased significantly in the ET group compared to the control group (13.8±2.5 to 16.1±2.6 mL/kg per minute [change, 2.3±2.2 mL/kg per minute] versus 12.8±2.6 to 12.5±3.4 mL/kg per minute [change, -0.3±2.1 mL/kg per minute]; P=0.0002). There were significant improvements in peak power output, exercise time, 6-minute walk distance, and ventilatory anaerobic threshold (all P<0.002). There was improvement in the physical QOL score (P=0.03) but not in the total score (P=0.11).

CONCLUSIONS

ET improves peak and submaximal exercise capacity in older patients with HFPEF.