Exercise responses of elderly patients with diastolic versus systolic heart failure

Physical Functioning in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent, yet interventions and therapies to improve outcomes remain limited. There has been increasing attention towards the impact of comorbidities and physical functioning (PF) on poor clinical outcomes within this population. In this review, we summarize and discuss the literature on PF in HFpEF, its association with clinical and patient-centered outcomes, and future advances in the care of HFpEF with respect to PF. Multiple PF metrics have been demonstrated to provide prognostic value within HFpEF, yet the data are less robust compared with other patient populations, highlighting the need for further investigation. The evaluation and detection of poor PF provides a potential strategy to improve care in HFpEF, and future studies are needed to understand if modulating PF improves clinical and/or patient-reported outcomes. LAY SUMMARY: • Patients with heart failure with preserved ejection fraction (HFpEF) commonly have impaired physical functioning (PF) demonstrated by limitations across a wide range of common PF metrics.• Impaired PF metrics demonstrate prognostic value for both clinical and patient-reported outcomes in HFpEF, making them plausible therapeutic targets to improve outcomes.• Clinical trials are ongoing to investigate novel methods of detecting, monitoring, and improving impaired PF to enhance HFpEF care.Heart failure with preserved ejection fraction (HFpEF) is increasingly prevalent, yet interventions and therapies to improve outcomes remain limited. As such, there has been increasing focus on the impact of physical performance (PF) on clinical and patient-centered outcomes. In this review, we discuss the state of PF in patients with HFpEF by examining the multitude of PF metrics available, their respective strengths and limitations, and their associations with outcomes in HFpEF. We highlight future advances in the care of HFpEF with respect to PF, particularly regarding the evaluation and detection of poor PF.

Role of cardiopulmonary exercise testing in clinical stratification in heart failure. A position paper from the Committee on Exercise Physiology and Training of the Heart Failure Association of the European Society of Cardiology

Traditionally, the main indication for cardiopulmonary exercise testing (CPET) in heart failure (HF) was for the selection of candidates to heart transplantation: CPET was mainly performed in middle-aged male patients with HF and reduced left ventricular ejection fraction. Today, CPET is used in broader patients' populations, including women, elderly, patients with co-morbidities, those with preserved ejection fraction, or left ventricular assistance device recipients, i.e. individuals with different responses to incremental exercise and markedly different prognosis. Moreover, the diagnostic and prognostic utility of symptom-limited CPET parameters derived from submaximal tests is more and more considered, since many patients are unable to achieve maximal aerobic power. Repeated tests are also being used for risk stratification and evaluation of intervention, so that these data are now available. Finally, patients, physicians and healthcare decision makers are increasingly considering how treatments might impact morbidity and quality of life rather than focusing more exclusively on hard endpoints (such as mortality) as was often the case in the past. Innovative prognostic flowcharts, with CPET at their core, that help optimize risk stratification and the selection of management options in HF patients, have been developed.

Hemodynamic response to muscle reflex is abnormal in patients with heart failure with preserved ejection fraction

The aim of the present investigation was to assess the role of cardiac diastole on the hemodynamic response to metaboreflex activation. We wanted to determine whether patients with diastolic function impairment showed a different hemodynamic response compared with normal subjects during this reflex. Hemodynamics during activation of the metaboreflex obtained by postexercise muscle ischemia (PEMI) was assessed in 10 patients with diagnosed heart failure with preserved ejection fraction (HFpEF) and in 12 age-matched healthy controls (CTL). Subjects also performed a control exercise-recovery test to compare data from the PEMI test. The main results were that patients with HFpEF achieved a similar mean arterial blood pressure (MAP) response as the CTL group during the PEMI test. However, the mechanism by which this response was achieved was markedly different between the two groups. Patients with HFpEF achieved the target MAP via an increase in systemic vascular resistance (+389.5 ± 402.9 vs. +80 ± 201.9 dynes·s^-1·cm^-5 for HFpEF and CTL groups respectively), whereas MAP response in the CTL group was the result of an increase in cardiac preload (-1.3 ± 5.2 vs. 6.1 ± 10 ml in end-diastolic volume for HFpEF and CTL groups, respectively), which led to a rise in stroke volume and cardiac output. Moreover, early filling peak velocities showed a higher response in the CTL group than in the HFpEF group. This study demonstrates that diastolic function is important for normal hemodynamic adjustment to the metaboreflex. Moreover, it provides evidence that HFpEF causes hemodynamic impairment similar to that observed in systolic heart failure.NEW & NOTEWORTHY This study provides evidence that diastolic function is important for normal hemodynamic responses during the activation of the muscle metaboreflex in humans. Moreover, it demonstrates that diastolic impairment leads to hemodynamic consequences similar to those provoked by systolic heart failure. In both cases the target blood pressure is obtained mainly by means of exaggerated vasoconstriction than by a flow-mediated mechanism.

Causes of exercise intolerance in heart failure with preserved ejection fraction: searching for consensus

Exercise intolerance is one of the cardinal symptoms of heart failure with preserved ejection fraction (HFpEF). We review its mechanistic basis using evidence from exercise studies. One barrier to a consensus understanding of the pathophysiology is heterogeneity of the patient population. Therefore, we pay special attention to varying study definitions of the disease and their possible impact on the causal factors that are implicated. We then discuss the role of exercise testing and its potential to subtype HFpEF in to more homogeneous mechanism-based subclasses.

Relationship of flow-mediated arterial dilation and exercise capacity in older patients with heart failure and preserved ejection fraction

BACKGROUND

Older heart failure patients with preserved ejection fraction (HFpEF) have severely reduced exercise capacity and quality of life. Both brachial artery flow-mediated dilation (FMD) and peak exercise oxygen uptake (peak VO(2)) decline with normal aging. However, uncertainty remains regarding whether FMD is reduced beyond the degree associated with normal aging and if this contributes to reduced peak VO(2) in elderly HFpEF patients.

METHODS

Sixty-six older (70 ± 7 years) HFpEF patients and 47 healthy participants (16 young, 25 ± 3 years, and 31 older, 70 ± 6 years) were studied. Brachial artery diameter was measured before and after cuff occlusion using high-resolution ultrasound. Peak VO(2) was measured using expired gas analysis during upright cycle exercise.

RESULTS

Peak VO(2) was severely reduced in older HFpEF patients compared with age-matched healthy participants (15.2 ± 0.5 vs 19.6 ± 0.6 mL/kg/min, p < .0001), and in both groups, peak VO(2) was reduced compared with young healthy controls (28.5 ± 0.8 mL/kg/min; both p < .0001). Compared with healthy young participants, brachial artery FMD (healthy young, 6.13% ± 0.53%) was significantly reduced in healthy older participants (4.0 ± 0.38; p < .0002) and in HFpEF patients (3.64% ± 0.28%; p < .0001). However, FMD was not different in HFpEF patients compared with healthy older participants (p = .86). Although brachial artery FMD was modestly related to peak VO(2) in univariate analyses (r = .19; p = .048), it was not related in multivariate analyses that accounted for age, gender, and body size.

CONCLUSION

These results suggest that endothelial dysfunction may not be a significant independent contributor to the severely reduced exercise capacity in elderly HFpEF patients.

Cardiopulmonary exercise testing: relevant but underused

Cardiopulmonary exercise testing (CPX) is a relatively old technology, but has sustained relevance for many primary care clinical scenarios in which it is, ironically, rarely considered. Advancing computer technology has made CPX easier to administer and interpret at a time when our aging population is more prone to comorbidities and higher prevalence of nonspecific symptoms of exercise intolerance and dyspnea, for which CPX is particularly useful diagnostically and prognostically. These discrepancies in application are compounded by patterns in which CPX is often administered and interpreted by cardiology, pulmonary, or exercise specialists who limit their assessments to the priorities of their own discipline, thereby missing opportunities to distinguish symptom origins. When used properly, CPX enables the physician to assess fitness and uncover cardiopulmonary issues at earlier phases of work-up, which would therefore be especially useful for primary care physicians. In this article, we provide an overview of CPX principles and testing logistics, as well as some of the clinical contexts in which it can enhance patient care.

Usefulness of peak exercise oxygen consumption and the heart failure survival score to predict survival in patients >65 years of age with heart failure

Peak exercise oxygen consumption (Vo(2)) and the Heart Failure (HF) Survival Score (HFSS) were developed in middle-aged patient cohorts referred for heart transplantation with HF. The prognostic value of Vo(2) in patients >65 years has not been well studied. Accordingly, the prognostic value of peak Vo(2) was evaluated in these patients with HF. A retrospective analysis of 396 patients with HF >65 years with cardiopulmonary exercise testing was performed. Peak Vo(2) and components of the HFSS (presence of coronary artery disease, left ventricular ejection fraction, heart rate, mean arterial blood pressure, presence of intraventricular conduction defects, and serum sodium) were collected. Follow-up averaged 1,038 +/- 983 days. Outcome events were defined as death, implantation of a left ventricular assist device, or urgent transplantation. Patients were divided into risk strata for peak Vo(2) and HFSS based on previous cut-off points. Survival curves were derived using Kaplan-Meier analysis and compared using log-rank analysis. Survival differed markedly by Vo(2) stratum (p <0.0001), with significantly better survival rates for the low- (>14 ml/kg/min) versus medium- (10 to 14 ml/kg/min), low- versus high- (<10 ml/kg/min), and medium- versus high-risk strata (all p <0.05). Survival also differed markedly by HFSS stratum (p <0.0001), with significantly better survival rates for the low- (> or =8.10) versus medium- (7.20 to 8.09), low- versus high- (< or =7.19), and medium- versus high-risk strata (all p <0.0001). In conclusion, peak Vo(2) and the HFSS were both excellent parameters to predict survival in patients >65 years with HF.

Diastolic dysfunction in exercise and its role for exercise capacity

Diastolic dysfunction is frequent in elderly subjects and in patients with left ventricular hypertrophy, vascular disease and diabetes mellitus. Patients with diastolic dysfunction demonstrate a reduced exercise capacity and might suffer from congestive heart failure (CHF). Presence of symptoms of CHF in the setting of a normal systolic function is referred to as heart failure with normal ejection fraction (HFNEF) or, if evidence of an impaired diastolic function is observed, as diastolic heart failure (DHF). Reduced exercise capacity in diastolic dysfunction results from a number of pathophysiological alterations such as slowed myocardial relaxation, reduced myocardial distensibility, elevated filling pressures, and reduced ventricular suction forces. These alterations limit the increase of ventricular diastolic filling and cardiac output during exercise and lead to pulmonary congestion. In healthy subjects, exercise training can enhance diastolic function and exercise capacity and prevent deterioration of diastolic function in the course of aging. In patients with diastolic dysfunction, exercise capacity can be enhanced by exercise training and pharmacological treatment, whereas improvement of diastolic function can only be observed in few patients.

Acute and Chronic Ventricular-Arterial Coupling in Systole and Diastole

Aging and hypertension lead to arterial remodeling and tandem increases in arterial (Ea) and ventricular (LV) systolic stiffness (ventricular-arterial [VA] coupling). Age and hypertension also predispose to heart failure with normal ejection fraction (HFnlEF), where symptoms during hypertensive urgencies or exercise are common. We hypothesized that: (1) chronic VA coupling also occurs in diastole, (2) acute changes in Ea are coupled with shifts in the diastolic and systolic pressure-volume relationships (PVR), and (3) diastolic VA coupling reflects changes in LV diastolic stiffness rather than external forces or relaxation. Old chronically hypertensive (OHT, n=8) and young normal (YNL, n=7) dogs underwent assessment of PVR (caval occlusion) and of aortic pressure, dimension, and flow, at baseline and during changes in afterload and preload. Concomitant changes in the slope/position of PVR were accounted for by calculating systolic (ESV 200 ) and diastolic (EDV 20 ) volumes at common pressures (capacitance). OHT displayed marked vascular remodeling. Indices reflecting the pulsatile component of Ea (aortic stiffness and systemic arterial compliance) were more impaired in OHT at any distending pressure. In both groups, acute increases in Ea were associated with decreases in ESV 200 and EDV 20 . However, at any load, OHT had lower ESV 200 and EDV 20 , associated with LV remodeling and myocardial endothelin activation. Acute changes in EDV 20 were not mediated by changes in relaxation or external forces. These observations provide insight into the mechanisms whereby arterial remodeling and acute and chronic VA coupling in both systole and diastole may predispose to and interact with increases in load to cause HFnlEF.

Prevalence and management of chronotropic incompetence in heart failure

Although chronotropic incompetence (CI) has been shown to have important prognostic value in asymptomatic and coronary artery disease populations, much less attention has been given to the prevalence and impact of CI in heart failure. There is considerable variability in the reported prevalence of chronotropic impairment (25%-70%) in the heart failure literature, likely due to a lack of a standardized definition and/or differing assessment methodologies. Although the exact prevalence of CI is debatable and the precise pathophysiologic mechanisms involved remain uncertain, there is unambiguous evidence indicating that chronotropic impairment contributes significantly to the myriad of cardiovascular, neuromuscular, pulmonary, and neurohormonal maladaptations known to negatively impact the physical functional and quality of life of most heart failure patients. Specifically, an inappropriate chronotropic response to exercise can decrease peak exercise oxygen uptake by as much as 15% to 20%. Therapeutic interventions to improve chronotropic function, including endurance exercise training and rate-adaptive pacing, although promising, still warrant further investigation.

The relationship of a 6-min walk to VO(2 peak) and VT in older heart failure patients

PURPOSE

To evaluate the relationship between a 6-min walk test (6-MWT) to peak oxygen consumption (VO(2 peak)) and ventilatory threshold (VT) in older heart failure (HF) patients, to validate the equation by Cahalin et al., and to develop a new equation to improve the prediction of VO(2 peak) from 6-MWT.

METHODS

Older patients (>65 yr) with systolic or diastolic HF (N=97) performed an exercise test to peak exertion on an upright bicycle ergometer using an incremental protocol. Gas exchange measures were collected along with continuous electrocardiograph monitoring. 6-MWT was performed on an indoor track at a self-selected pace under standardized conditions. The formula of Cahalin et al. was used to predict VO(2 peak) from 6-MWT, and a new equation was generated from the measured VO(2 peak)-6-MWT relationship from this investigation.

RESULTS

The correlation between 6-MWT and measured VO(2 peak) was moderate (r=0.54) with a standard error of estimate (SEE) of 2.48 mL.kg.min. The correlation between 6-MWT and VT was weak (r=0.23), whereas the correlation between VO(2 peak) and VT was strong (r=0.74). Correlations between the measured and predicted VO(2 peak) values were moderate (r=0.54) for both prediction equations, and the SEE was 2.83 versus 1.34 mL.kg.min for the Cahalin et al. and the new equation, respectively.

CONCLUSION

These results indicate that 6-MWT does not accurately predict functional capacity in older HF patients, and questions the validity of using this test to determine functional capacity in older HF patients. Predicting VO(2 peak) from equations using 6-MWT also results in substantial variability and, consequently, should not be used in older HF patients where an accurate determination of functional capacity is essential.

Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study

OBJECTIVE

Whereas caffeine has been demonstrated to impact substantially on the metabolic response to exercise in healthy young subjects, this issue remains to be addressed in healthy elderly subjects.

DESIGN AND PATIENTS

The metabolic response to caffeine ingestion (6 mg/kg) and exercise in healthy elderly citizens at 70 years was examined in a randomized, double-blind, placebo-controlled, cross-over study. We included 30 subjects attending for driver license renewal at their general practitioner. Participants abstained from caffeinated drinks and food for 48 h and were randomized to receive placebo-caffeine or caffeine-placebo with 1 week between sessions.

MEASUREMENTS

A cycling endurance test at 65% of the expected maximal heart rate was performed 1 h after intervention. Blood samples were taken before intervention, before cycling, after 5 min of cycling, and at exhaustion. Analysis was by intention-to-treat and P < 0.05 was regarded as significant.

RESULTS

Caffeine significantly increased the concentration of plasma epinephrine (by 42%, 39%, and 49%), serum-free fatty acids (by 53%, 44%, and 50%), and plasma lactate (by 46%, 36%, and 48%), and insulin resistance (homeostasis model assessment-IR) (by 21%, 26%, and 23%) during rest, after 5 min of cycling, and at exhaustion. At exhaustion, the concentration plasma norepinephrine was elevated by 29%. A decrease was seen with caffeine treatment in blood potassium after 5 min of cycling and at exhaustion (by 3% and 2%, respectively).

CONCLUSIONS

Caffeine treatment increased epinephrine, fatty acids, lactate and norepinephrine at different times during test session and led to insulin-resistance. Hence, caffeine ingestion elicits a similar metabolic response in elderly participants at 70 years old to that seen in younger subjects.

Anabolic growth hormone action improves submaximal measures of physical performance in patients with HIV-associated wasting

Growth hormone (GH) treatment reverses the muscle loss allegedly responsible for diminished aerobic capacity and increased fatigue in patients with HIV-associated wasting. This study examined whether submaximal measures of physical performance can be used as objective measures of the functional impact of GH treatment-induced anabolism. We randomized 27 HIV-positive men [mean (SD) age, 43.9 (7.2) yr; body mass, 71.9 (10.4) kg; BMI, 23.1 (2.8) kg/m2] with unintentional weight loss despite antiretroviral therapy to receive GH (6 mg) or placebo in a double-blinded, placebo-controlled, cross-over trial with a 3-mo washout. Lean body mass (LBM), maximum oxygen uptake (Vo2 peak), ventilatory threshold (VeT), 6-min walk test (6MWT) distance and work, profile of mood states (POMS) fatigue and vigor scores, and Nottingham health profile (NHP) energy and physical mobility scores were measured. LBM significantly increased after 3 mo of GH treatment vs. placebo (means +/- SE, 3.7 +/- 0.6 vs. 0.3 +/- 0.4 kg; P < 0.001). VeT significantly improved (17.6 +/- 3.7 vs. -5.9 +/- 2.5%; P < 0.001), but Vo2 peak did not change significantly. 6MWT distance improved (24.9 +/- 9.7 vs. 19.9 +/- 11.6 m; P > 0.05) and 6MWT work increased significantly more after 3 mo of GH treatment (33.3 +/- 8.8 vs. 16.5 +/- 7.5 kJ; P < 0.05). POMS scores of fatigue and vigor and the NHP score of energy improved, yet the changes were not statistically significant. GH treatment improved VeT linearly to the increase in LBM (r =0.43, P = 0.037) and 6MWT work (r = 0.51, P = 0.008), and the increase in 6MWT work correlated with increase in LBM (r = 0.45, P = 0.024). Improvement in 6MWT work above the median (27.3 kJ) showed a decrease in fatigue (r = -0.62, P = 0.024). We concluded that GH treatment-induced LBM gains in HIV-associated wasting were functionally relevant, as determined by effort-independent submaximal measures of cardiopulmonary exercise testing.