Hemodynamic Correlates and Diagnostic Role of Cardiopulmonary Exercise Testing in Heart Failure With Preserved Ejection Fraction

Safety and efficacy of adaptive atrial pacing regulated by blood pressure during low-level exercise: a proof-of-concept study

AIMS

Despite half of all heart failure patients suffering from heart failure with preserved ejection fraction (HFpEF), treatment options are limited. This study aims to compare safety and efficacy of standard pacemaker programming (DDD or DDDR) and a novel pacing algorithm PressurePace™ (BaroPace Inc, Issaquah, WA, USA) which modulates atrial pacing rate based on blood pressure (BPAP).

METHODS

This prospective, randomized, double-blind, non-significant risk proof of concept study was conducted at two large cardiology clinics in Los Angeles, California, USA. Subjects underwent two modified Bruce protocol graded treadmill exercise tests in which pacemaker programming was randomized to either standard programming (DDD or DDDR), or BPAP at least 1 week apart. Physiological measurements of heart rate (HR), and systolic and diastolic blood pressure (BP) were collected at 2 min intervals. During the BPAP treadmill test, the pacemaker activity sensor was disabled. The PressurePace algorithm instructed the pacemaker technician to modify or leave unchanged the atrial pacing rate based on these BP measurements. Subjects and clinical staff were blinded to pacemaker programming, only the pacemaker technician was unblinded.

RESULTS

Ten subjects with HFpEF associated with hypertension who also had permanent dual-chamber pacemakers, previously implanted for standard clinical indications, participated in the study. Mean age was 70.1 ± 6.8 years, left ventricular ejection fraction of 54.8 ± 1.9%. Exercise duration increased in all 10 subjects, when paced in the BPAP mode compared with standard pacemaker programming, showing a mean increase of 117 s (26%, P = 0.0016). The algorithm could adjust HR at each 2 min interval. The majority of subjects (60%) had their atrial pacing rate increased an average of 20% at t = 2 min. In the remaining 40% of subjects, the algorithm instructed HR to be unchanged. In two subjects, the pacing rate was not increased until t = 6 min. In contrast, subjects programmed to DDDR experienced an average of 45% increase in atrial pacing rate at t = 2 min. In the post-treadmill recovery period, SBP was higher for subjects who underwent BPAP. This difference in SBP was most pronounced immediately post-treadmill and diminished as subjects progressed through the 30 min recovery period. Statistical significance was achieved at t = 0, 20, and 30 min post-treadmill.

CONCLUSIONS

An increase in exercise duration was reported in HFpEF subjects using a pacing algorithm that modulated HR based on BP compared with standard programming. These encouraging results form the basis for a larger, randomized cross-over trial to confirm these initial observations, further characterize the safety, efficacy, and possible mechanisms of action in both acute and longer-term treatment.

Long-term prognostic value of the H2FPEF score in patients undergoing transcatheter aortic valve implantation

AIMS

A considerable proportion of candidates for transcatheter aortic valve implantation (TAVI) have underlying heart failure (HF) with preserved ejection fraction (HFpEF), which can be challenging for diagnosis because significant valvular heart disease should be excluded before diagnosing HFpEF. This study investigated the long-term prognostic value of the pre-procedural H2FPEF score in patients with preserved ejection fraction (EF) undergoing TAVI.

METHODS AND RESULTS

Patients who underwent TAVI between October 2013 and May 2017 were enrolled from the Optimized CathEter vAlvular iNtervention-Transcatheter Aortic Valve Implantation Japanese multicentre registry. After excluding 914 patients, 1674 patients with preserved EF ≥ 50% (median age: 85 years, 72% female) were selected for calculation of the H2FPEF score and were dichotomized into two groups: the low H2FPEF score [0-5 points; n = 1399 (83.6%)] group and the high H2FPEF score [6-9 points; n = 275 (16.4%)] group. Patients with high H2FPEF scores were associated with a higher prevalence of New York Heart Association Functional Class III/IV (59.3% vs. 43.7%, P < 0.001), diabetes (24.4% vs. 18.5%, P = 0.03), and paradoxical low-flow, low-gradient aortic stenosis (15.9% vs. 6.2%, P < 0.001). These patients showed worse prognoses than those with low H2FPEF scores regarding the cumulative 2 year all-cause mortality (26.3% vs. 15.5%, log-rank P < 0.001), cardiovascular mortality (10.5% vs. 5.4%, log-rank P < 0.001), HF hospitalization (16.2% vs. 6.7%, log-rank P < 0.001), and the composite endpoint of cardiovascular mortality and HF hospitalization (23.8% vs. 10.8%, log-rank P < 0.001). After adjustment for several confounders, the high H2FPEF scores were independently associated with increased risk for all-cause mortality [adjusted hazard ratio (HR), 1.48; 95% confidence interval (CI), 1.09-2.00; P = 0.011] and for the composite endpoint of cardiovascular mortality and HF hospitalization (adjusted HR, 1.95; 95% CI, 1.38-2.74; P < 0.001). Subgroup analysis confirmed the excess risk of high H2FPEF scores relative to low H2FPEF scores for the composite endpoint of cardiovascular mortality and HF hospitalization increased with a lower Society of Thoracic Surgeons (STS) score (STS score <8%: adjusted HR, 2.40; 95% CI, 1.50-3.85; P < 0.001; STS score ≥8%: adjusted HR, 1.34; 95% CI, 0.79-2.28; P = 0.28; Pinteraction = 0.030).

CONCLUSIONS

The H2FPEF score is useful for predicting long-term adverse outcomes after TAVI, including all-cause mortality, cardiovascular mortality, and HF hospitalization for patients with preserved EF. More aggressive interventions targeting HFpEF in addition to the TAVI procedure might be relevant in patients with high H2FPEF scores, particularly in those with a lower surgical risk.

Dapagliflozin and Right Ventricular-Pulmonary Vascular Interaction in Heart Failure With Preserved Ejection Fraction: A Secondary Analysis of a Randomized Clinical Trial

Importance

Increases in pulmonary capillary wedge pressure (PCWP) during exercise reduce pulmonary artery (PA) compliance, increase pulsatile right ventricular (RV) afterload, and impair RV-PA coupling in patients with heart failure with preserved ejection fraction (HFpEF). The effects of the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin on pulmonary vascular properties and RV-PA coupling are unknown.

Objective

To test the effect of dapagliflozin on right ventricular performance and pulmonary vascular load during exertion in HFpEF.

Design, Setting, and Participants

Evaluation of the Cardiac and Metabolic Effects of Dapagliflozin in Heart Failure With Preserved Ejection Fraction (CAMEO-DAPA) randomized clinical trial demonstrated improvement in PCWP at rest and exercise over 24 weeks with dapagliflozin compared with placebo with participants recruited between February 2021 and May 2022. This secondary analysis evaluates the effects of dapagliflozin on pulsatile pulmonary vascular load and RV-PA coupling using simultaneous echocardiography and high-fidelity invasive hemodynamic testing with exercise. This was a single-center study including patients with hemodynamically confirmed HFpEF with exercise PCWP of 25 mm Hg or greater.

Interventions

Dapagliflozin or placebo for 24 weeks.

Main Outcomes and Measures

Pulsatile pulmonary vascular load (PA compliance and elastance) and right ventricular performance (PA pulsatility index, RV systolic velocity [s']/PA mean) during rest and exercise.

Results

Among 37 randomized participants (mean [SD] age, 67.4 [8.5] years; 25 female [65%]; mean [SD] body mass index, 34.9 [6.7]; calculated as weight in kilograms divided by height in meters squared), there was no effect of dapagliflozin on PA loading or RV-PA interaction at rest. However, with exercise, dapagliflozin improved PA compliance (placebo-corrected mean difference, 0.57 mL/mm Hg; 95% CI, 0.11-1.03 mL/mm Hg; P = .02) and decreased PA elastance (stiffness; -0.17 mm Hg/mL; 95% CI, -0.28 to -0.07 mm Hg/mL; P = .001). RV function during exercise improved, with increase in PA pulsatility index (0.33; 95% CI, 0.08-0.59; P = .01) and increase in exercise RV s' indexed to PA pressure (0.09 cm·s-1/mm Hg; 95% CI, 0.02-0.16 cm·s-1/mm Hg; P = .01). Improvements in pulsatile RV load and RV-PA coupling were correlated with reduction in right atrial (RA) pressure (PA elastance Pearson r = 0.55; P =.008; RV s'/PA elastance Pearson r = -0.60; P =.002) and PCWP (PA elastance Pearson r = 0.58; P <.001; RV s'/PA elastance Pearson r = -0.47; P = .02). Dapagliflozin increased resistance-compliance time (dapagliflozin, median [IQR] change, 0.06 [0.03-0.15] seconds; placebo, median [IQR] change, 0.01 [-0.02 to 0.05] seconds; P =.046), resulting in higher PA compliance for any exercise pulmonary vascular resistance.

Conclusions and Relevance

Results of this randomized clinical trial reveal that treatment with dapagliflozin for 24 weeks reduced pulsatile pulmonary vascular load and enhanced dynamic RV-PA interaction during exercise in patients with HFpEF, findings that are related to the magnitude of PCWP reduction. Benefits on dynamic right ventricular-pulmonary vascular coupling may partially explain the benefits of SGLT2 inhibitors in HFpEF.

Trial Registration

ClinicalTrials.gov Identifier: NCT04730947.

The roles of exercise stress echocardiography for the evaluation of heart failure with preserved ejection fraction in the heart failure pandemic era

Heart failure with preserved ejection fraction (HFpEF) accounts for nearly 70% of all HF and has become the dominant form of HF. The increased prevalence of HFpEF has contributed to a rise in the number of HF patients, known as the "heart failure pandemic". In addition to the fact that HF is a progressive disease and a delayed diagnosis may worsen clinical outcomes, the emergence of disease-modifying treatments such as sodium-glucose transporter 2 inhibitors and glucagon-like peptide-1 receptor agonists has made appropriate and timely identification of HFpEF even more important. However, diagnosis of HFpEF remains challenging in patients with a lower degree of congestion. In addition to normal EF, this is related to the fact that left ventricular (LV) filling pressures are often normal at rest but become abnormal during exercise. Exercise stress echocardiography can identify such exercise-induced elevations in LV filling pressures and facilitate the diagnosis of HFpEF. Exercise stress echocardiography may also be useful for risk stratification and assessment of exercise tolerance as well as cardiovascular responses to exercise. Recent attention has focused on dedicated dyspnea clinics to identify early HFpEF among patients with unexplained dyspnea and to investigate the causes of dyspnea. This review discusses the role of exercise stress echocardiography in the diagnosis and evaluation of HFpEF.

Two-hit mouse model of heart failure with preserved ejection fraction combining diet-induced obesity and renin-mediated hypertension

Heart failure with preserved ejection fraction (HFpEF) is increasingly common but its pathogenesis is poorly understood. The ability to assess genetic and pharmacologic interventions is hampered by the lack of robust preclinical mouse models of HFpEF. We have developed a novel "2-hit" model, which combines obesity and insulin resistance with chronic pressure overload to recapitulate clinical features of HFpEF. C57BL6/NJ mice fed a high fat diet for >10 weeks were administered an AAV8-driven vector resulting in constitutive overexpression of mouse Renin1d . Control mice, HFD only, Renin only and HFD-Renin (aka "HFpEF") littermates underwent a battery of cardiac and extracardiac phenotyping. HFD-Renin mice demonstrated obesity and insulin resistance, a 2-3-fold increase in circulating renin levels that resulted in 30-40% increase in left ventricular hypertrophy, preserved systolic function, and diastolic dysfunction indicated by altered E/e', IVRT, and strain measurements; increased left atrial mass; elevated natriuretic peptides; and exercise intolerance. Transcriptomic and metabolomic profiling of HFD-Renin myocardium demonstrated upregulation of pro-fibrotic pathways and downregulation of metabolic pathways, in particular branched chain amino acid catabolism, similar to findings in human HFpEF. Treatment of these mice with the sodium-glucose cotransporter 2 inhibitor empagliflozin, an effective but incompletely understood HFpEF therapy, improved exercise tolerance, left heart enlargement, and insulin homeostasis. The HFD-Renin mouse model recapitulates key features of human HFpEF and will enable studies dissecting the contribution of individual pathogenic drivers to this complex syndrome. Addition of HFD-Renin mice to the preclinical HFpEF model platform allows for orthogonal studies to increase validity in assessment of interventions.

NEW & NOTEWORTHY

Heart failure with preserved ejection fraction (HFpEF) is a complex disease to study due to limited preclinical models. We rigorously characterize a new two-hit HFpEF mouse model, which allows for dissecting individual contributions and synergy of major pathogenic drivers, hypertension and diet-induced obesity. The results are consistent and reproducible in two independent laboratories. This high-fidelity pre-clinical model increases the available, orthogonal models needed to improve our understanding of the causes and assessment treatments for HFpEF.

Prognostic utility of cardiopulmonary exercise testing with simultaneous exercise echocardiography in heart failure with preserved ejection fraction

AIMS

Cardiopulmonary exercise testing (CPET) combined with exercise echocardiography (CPETecho) allows simultaneous assessments of cardiac, pulmonary, and ventilation in heart failure (HF) with preserved ejection fraction (HFpEF). This study sought to determine whether simultaneous assessment of CPET variables could provide additive predictive value over exercise stress echocardiography in patients with dyspnoea.

METHODS AND RESULTS

CPETecho was performed in 443 patients with suspected HFpEF (240 HFpEF and 203 controls without HF). Patients with HFpEF were divided based on peak oxygen consumption (VO2, ≥10 or <10 ml/min/kg) or the slope of minute ventilation to carbon dioxide production (VE vs. VCO2 slope ≥45.0 or <45.0). The primary endpoint was defined as a composite of all-cause mortality, HF hospitalization, unplanned hospital visits requiring intravenous diuretics, or intensification of oral diuretics. During a median follow-up of 399 days, the composite outcome occurred in 57 patients. E/e' ratio during peak exercise was associated with adverse outcomes. Patients with HFpEF and lower peak VO2 had increased risks of the composite event (hazard ratio [HR] 5.05, 95% confidence interval [CI] 2.65-9.62, p < 0.0001 vs. controls; HR 3.14, 95% CI 1.69-5.84, p = 0.0003 vs. HFpEF with higher peak VO2). Elevated VE versus VCO2 slope was also associated with adverse events in HFpEF. The addition of either the presence of abnormal peak VO2 or VE versus VCO2 slope increased the predictive ability over the model based on age, sex, atrial fibrillation, left atrial volume index, and exercise E/e' (p < 0.05).

CONCLUSION

These data provide new insights into the role of CPETecho in patients with HFpEF.

Exercise Stress Echocardiography-Based Phenotyping of Heart Failure With Preserved Ejection Fraction

BACKGROUND

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome requiring improved phenotypic classification. Previous studies have identified subphenotypes of HFpEF, but the lack of exercise assessment is a major limitation. The aim of this study was to identify distinct pathophysiologic clusters of HFpEF based on clinical characteristics, and resting and exercise assessments.

METHODS

A total of 265 patients with HFpEF underwent ergometry exercise stress echocardiography with simultaneous expired gas analysis. Cluster analysis was performed by the K-prototype method with 21 variables (10 clinical and resting echocardiographic variables and 11 exercise echocardiographic parameters). Pathophysiologic features, exercise tolerance, and prognosis were compared among phenogroups.

RESULTS

Three distinct phenogroups were identified. Phenogroup 1 (n = 112 [42%]) was characterized by preserved biventricular systolic reserve and cardiac output augmentation. Phenogroup 2 (n = 58 [22%]) was characterized by a high prevalence of atrial fibrillation, increased pulmonary arterial and right atrial pressures, depressed right ventricular systolic functional reserve, and impaired right ventricular-pulmonary artery coupling during exercise. Phenogroup 3 (n = 95 [36%]) was characterized by the smallest body mass index, ventricular and vascular stiffening, impaired left ventricular diastolic reserve, and worse exercise capacity. Phenogroups 2 and 3 had higher rates of composite outcomes of all-cause mortality or heart failure events than phenogroup 1 (log-rank P = .02).

CONCLUSION

Exercise echocardiography-based cluster analysis identified three distinct phenogroups of HFpEF, with unique exercise pathophysiologic features, exercise capacity, and clinical outcomes.

Exercise intolerance in heart failure with preserved ejection fraction: Causes, consequences and the journey towards a cure

Heart failure with preserved ejection fraction (HFpEF) accounts for over 50% of all heart failure cases nationwide and continues to rise in its prevalence. The complex, multi-organ involvement of the HFpEF clinical syndrome requires clinicians and investigators to adopt an integrative approach that considers the contribution of both cardiac and non-cardiac function to HFpEF pathophysiology. Thus, this symposium review outlines the key points from presentations covering the contributions of disease-related changes in cardiac function, arterial stiffness, peripheral vascular function, and oxygen delivery and utilization to exercise tolerance in patients with HFpEF. While many aspects of HFpEF pathophysiology remain poorly understood, there is accumulating evidence for a decline in vascular health in this patient group that may be remediable through pharmacological and lifestyle interventions and could improve outcomes and clinical status in this ever-growing patient population.

Clinical phenogroup diversity and multiplicity: Impact on mechanisms of exercise intolerance in heart failure with preserved ejection fraction

AIMS

We aimed to clarify the extent to which cardiac and peripheral impairments to oxygen delivery and utilization contribute to exercise intolerance and risk for adverse events, and how this relates to diversity and multiplicity in pathophysiologic traits.

METHODS AND RESULTS

Individuals with heart failure with preserved ejection fraction (HFpEF) and non-cardiac dyspnoea (controls) underwent invasive cardiopulmonary exercise testing and clinical follow-up. Haemodynamics and oxygen transport responses were compared. HFpEF patients were then categorized a priori into previously-proposed, non-exclusive descriptive clinical trait phenogroups, including cardiometabolic, pulmonary vascular disease, left atrial myopathy, and vascular stiffening phenogroups based on clinical and haemodynamic profiles to contrast pathophysiology and clinical risk. Overall, patients with HFpEF (n = 643) had impaired cardiac output reserve with exercise (2.3 vs. 2.8 L/min, p = 0.025) and greater reliance on peripheral oxygen extraction augmentation (4.5 vs. 3.8 ml/dl, p < 0.001) compared to dyspnoeic controls (n = 219). Most (94%) patients with HFpEF met criteria for at least one clinical phenogroup, and 67% fulfilled criteria for multiple overlapping phenogroups. There was greater impairment in peripheral limitations in the cardiometabolic group and greater cardiac output limitations and higher pulmonary vascular resistance during exertion in the other phenogroups. Increasing trait multiplicity within a given patient was associated with worse exercise haemodynamics, poorer exercise capacity, lower cardiac output reserve, and greater risk for heart failure hospitalization or death (hazard ratio 1.74, 95% confidence interval 1.08-2.79 for 0-1 vs. ≥2 phenogroup traits present).

CONCLUSIONS

Though cardiac output response to exercise is limited in patients with HFpEF compared to those with non-cardiac dyspnoea, the relative contributions of cardiac and peripheral limitations vary with differing numbers and types of clinical phenotypic traits present. Patients fulfilling criteria for greater multiplicity and diversity of HFpEF phenogroup traits have poorer exercise capacity, worsening haemodynamic perturbations, and greater risk for adverse outcome.

Novel Strategies in Diagnosing Heart Failure with Preserved Ejection Fraction: A Comprehensive Literature Review

Heart failure (HF) with preserved ejection fraction (HFpEF) is a prevalent global condition affecting approximately 50% of the HF population. With the aging of the worldwide population, its incidence and prevalence are expected to rise even further. Unfortunately, until recently, no effective medications were available to reduce the high mortality and hospitalization rates associated with HFpEF, making it a significant unmet need in cardiovascular medicine. Although HFpEF is commonly defined as HF with normal ejection fraction and elevated left ventricular filling pressure, performing invasive hemodynamic assessments on every individual suspected of having HFpEF is neither feasible nor practical. Consequently, several clinical criteria and diagnostic tools have been proposed to aid in diagnosing HFpEF. Overall, these criteria and tools are designed to assist healthcare professionals in identifying and evaluating patients who may have HFpEF based on a combination of signs, symptoms, biomarkers, and non-invasive imaging findings. By employing these non-invasive diagnostic approaches, clinicians can make informed decisions regarding the best pharmacological and rehabilitation strategies for individuals with suspected HFpEF. This literature review aims to provide an overview of all currently available methods for diagnosing and monitoring this disabling condition.

Inorganic Nitrite to Amplify the Benefits and Tolerability of Exercise Training in Heart Failure With Preserved Ejection Fraction: The INABLE-Training Trial

OBJECTIVE

To determine whether nitrite can enhance exercise training (ET) effects in heart failure with preserved ejection fraction (HFpEF).

METHODS

In this multicenter, double-blind, placebo-controlled, randomized trial conducted at 1 urban and 9 rural outreach centers between November 22, 2016, and December 9, 2021, patients with HFpEF underwent ET along with inorganic nitrite 40 mg or placebo 3 times daily. The primary end point was peak oxygen consumption (VO2). Secondary end points included Kansas City Cardiomyopathy Questionnaire overall summary score (KCCQ-OSS, range 0 to 100; higher scores reflect better health status), 6-minute walk distance, and actigraphy.

RESULTS

Of 92 patients randomized, 73 completed the trial because of protocol modifications necessitated by loss of drug availability. Most patients were older than 65 years (80%), were obese (75%), and lived in rural settings (63%). At baseline, median peak VO2 (14.1 mL·kg-1·min-1) and KCCQ-OSS (63.7) were severely reduced. Exercise training improved peak VO2 (+0.8 mL·kg-1·min-1; 95% CI, 0.3 to 1.2; P<.001) and KCCQ-OSS (+5.5; 95% CI, 2.5 to 8.6; P<.001). Nitrite was well tolerated, but treatment with nitrite did not affect the change in peak VO2 with ET (nitrite effect, -0.13; 95% CI, -1.03 to 0.76; P=.77) or KCCQ-OSS (-1.2; 95% CI, -7.2 to 4.9; P=.71). This pattern was consistent across other secondary outcomes.

CONCLUSION

For patients with HFpEF, ET administered for 12 weeks in a predominantly rural setting improved exercise capacity and health status, but compared with placebo, treatment with inorganic nitrite did not enhance the benefit from ET.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02713126.

Study the relationship between left atrial (LA) volume and left ventricular (LV) diastolic dysfunction and LV hypertrophy: Correlate LA volume with cardiovascular risk factors

Heart failure (HF) with normal ejection fraction - the isolated diastolic heart failure, depicts increasing prevalence and health care burden in recent times. Having less mortality rate compared to systolic heart failure but high morbidity, it is evolving as a major cardiac concern. With increasing clinical use of Left atrial volume (LAV) quantitation in clinical settings, LAV has emerged as an important independent predictor of cardiovascular outcome in HF with normal ejection fraction. This article is intended to review the diastolic and systolic heart failure, their association with left atrial volume, in depth study of Left atrial function dynamics with determinants of various functional and structural changes.

Pathophysiologic and prognostic importance of cardiac power output reserve in heart failure with preserved ejection fraction

AIMS

Heart failure with preserved ejection fraction (HFpEF) is a syndrome characterized by multiple cardiac reserve limitations during exercise. Cardiac power output (CPO) is an index of global cardiac performance and can be estimated non-invasively by echocardiography. We hypothesized that CPO reserve during exercise would be associated with impaired cardiovascular reserve, exercise intolerance, and adverse outcomes in HFpEF.

METHODS AND RESULTS

Exercise stress echocardiography was performed in 425 dyspnoeic patients [217 HFpEF and 208 non-heart failure (HF) controls] to estimate CPO at rest and during exercise. We classified patients with HFpEF based on the median value of changes in CPO from rest to peak exercise (ΔCPO >0.49 W/100 g). Patients with HFpEF and a lower CPO reserve had poorer biventricular systolic function, impaired chronotropic response during exercise, and worse aerobic capacity than controls and those with a higher CPO reserve. During a median follow-up of 358 days, a composite outcome of all-cause mortality or HF events occurred in 30 patients. Patients with a lower CPO reserve had four-fold and nearly 10-fold increased risks of the outcomes compared with those with a higher CPO reserve and controls, respectively [hazard ratio (HR) 4.05, 95% confidence interval (CI) 1.16-10.1, P = 0.003 and HR 9.61, 95% CI 3.58-25.8, P < 0.0001]. We further found that a lower CPO reserve had an incremental prognostic value over the H2FPEF score and exercise duration. In contrast, resting CPO did not predict clinical outcomes in patients with HFpEF.

CONCLUSION

A lower CPO reserve was associated with biventricular systolic dysfunction, chronotropic incompetence, exercise intolerance, and adverse outcomes in patients with HFpEF.

Comprehensive diagnostic workup in patients with suspected heart failure and preserved ejection fraction

Diagnosis of heart failure with preserved ejection fraction (HFpEF) can be challenging and it could require different tests, some of which are affected by limited availability. Nowadays, considering that new therapies are available for HFpEF and related conditions, a prompt and correct diagnosis is relevant. However, the diagnostic role of biomarker level, imaging tools, score-based algorithms and invasive evaluation, should be based on the strengths and weaknesses of each test. The aim of this review is to help the clinician in diagnosing HFpEF, overcoming the diagnostic uncertainty and disentangling among the different underlying causes, in order to properly treat this kind of patient.

Effects of aging and endurance exercise training on cardiorespiratory fitness and cardiac structure and function in healthy midlife and older women

Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in women in developed societies. Unfavorable structural and functional adaptations within the heart and central blood vessels with sedentary aging in women can act as the substrate for the development of debilitating CVD conditions such as heart failure with preserved ejection fraction (HFpEF). The large decline in cardiorespiratory fitness, as indicated by maximal or peak oxygen uptake (V̇o2max and V̇o2peak, respectively), that occurs in women as they age significantly affects their health and chronic disease status, as well as the risk of cardiovascular and all-cause mortality. Midlife and older women who have performed structured endurance exercise training for several years or decades of their adult lives exhibit a V̇o2max and cardiac and vascular structure and function that are on par or even superior to much younger sedentary women. Therefore, regular endurance exercise training appears to be an effective preventative strategy for mitigating the adverse physiological cardiovascular adaptations associated with sedentary aging in women. Herein, we narratively describe the aging and short- and long-term endurance exercise training adaptations in V̇o2max, cardiac structure, and left ventricular systolic and diastolic function at rest and exercise in midlife and older women. The role of circulating estrogens on cardiac structure and function is described for consideration in the timing of exercise interventions to maximize beneficial adaptations. Current research gaps and potential areas for future investigation to advance our understanding in this critical knowledge area are highlighted.

Cardiac and Metabolic Effects of Dapagliflozin in Heart Failure With Preserved Ejection Fraction: The CAMEO-DAPA Trial

BACKGROUND

Sodium-glucose cotransporter-2 inhibitors reduce risk of hospitalization for heart failure in patients who have heart failure with preserved ejection fraction (HFpEF), but the hemodynamic mechanisms underlying these benefits remain unclear. This study sought to determine whether treatment with dapagliflozin affects pulmonary capillary wedge pressure (PCWP) at rest and during exercise in patients with HFpEF.

METHODS

This was a single-center, double-blinded, randomized, placebo-controlled trial testing the effects of 10 mg of dapagliflozin once daily in patients with HFpEF. Patients with New York Heart Association class II or III heart failure, ejection fraction ≥50%, and elevated PCWP during exercise were recruited. Cardiac hemodynamics were measured at rest and during exercise using high-fidelity micromanometers at baseline and after 24 weeks of treatment. The primary end point was a change from baseline in rest and peak exercise PCWPs that incorporated both measurements, and was compared using a mixed-model likelihood ratio test. Key secondary end points included body weight and directly measured blood and plasma volumes. Expired gas analysis was performed evaluate oxygen transport in tandem with arterial lactate sampling.

RESULTS

Among 38 patients completing baseline assessments (median age 68 years; 66% women; 71% obese), 37 completed the trial. Treatment with dapagliflozin resulted in reduction in the primary end point of change in PCWP at rest and during exercise at 24 weeks relative to treatment with placebo (likelihood ratio test for overall changes in PCWP; P<0.001), with lower PCWP at rest (estimated treatment difference [ETD], -3.5 mm Hg [95% CI, -6.6 to -0.4]; P=0.029) and maximal exercise (ETD, -5.7 mm Hg [95% CI, -10.8 to -0.7]; P=0.027). Body weight was reduced with dapagliflozin (ETD, -3.5 kg [95% CI, -5.9 to -1.1]; P=0.006), as was plasma volume (ETD, -285 mL [95% CI, -510 to -60]; P=0.014), but there was no significant effect on red blood cell volume. There were no differences in oxygen consumption at 20-W or peak exercise, but dapagliflozin decreased arterial lactate at 20 W (-0.70 ± 0.77 versus 0.37 ± 1.29 mM; P=0.006).

CONCLUSIONS

In patients with HFpEF, treatment with dapagliflozin reduces resting and exercise PCWP, along with the favorable effects on plasma volume and body weight. These findings provide new insight into the hemodynamic mechanisms of benefit with sodium-glucose cotransporter-2 inhibitors in HFpEF.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04730947.

Hypoxaemia in patients with heart failure and preserved ejection fraction

AIMS

It is widely held that heart failure (HF) does not cause exertional hypoxaemia, based upon studies in HF with reduced ejection fraction, but this may not apply to patients with HF and preserved ejection fraction (HFpEF). Here, we characterize the prevalence, pathophysiology, and clinical implications of exertional arterial hypoxaemia in HFpEF.

METHODS AND RESULTS

Patients with HFpEF (n = 539) and no coexisting lung disease underwent invasive cardiopulmonary exercise testing with simultaneous blood and expired gas analysis. Exertional hypoxaemia (oxyhaemoglobin saturation <94%) was observed in 136 patients (25%). As compared to those without hypoxaemia (n = 403), patients with hypoxaemia were older and more obese. Patients with HFpEF and hypoxaemia had higher cardiac filling pressures, higher pulmonary vascular pressures, greater alveolar-arterial oxygen difference, increased dead space fraction, and greater physiologic shunt compared to those without hypoxaemia. These differences were replicated in a sensitivity analysis where patients with spirometric abnormalities were excluded. Regression analyses revealed that increases in pulmonary arterial and pulmonary capillary pressures were related to lower arterial oxygen tension (PaO2 ), especially during exercise. Body mass index (BMI) was not correlated with the arterial PaO2 , and hypoxaemia was associated with increased risk for death over 2.8 (interquartile range 0.7-5.5) years of follow-up, even after adjusting for age, sex, and BMI (hazard ratio 2.00, 95% confidence interval 1.01-3.96; p = 0.046).

CONCLUSION

Between 10% and 25% of patients with HFpEF display arterial desaturation during exercise that is not ascribable to lung disease. Exertional hypoxaemia is associated with more severe haemodynamic abnormalities and increased mortality. Further study is required to better understand the mechanisms and treatment of gas exchange abnormalities in HFpEF.

Biventricular cardiac power reserve in heart failure with preserved ejection fraction

AIMS

Cardiac and extracardiac abnormalities play important roles in heart failure with preserved ejection fraction (HFpEF). Biventricular cardiac power output (BCPO) quantifies the total rate of hydraulic work performed by both ventricles, suggesting that it may help to identify patients with HFpEF and more severe cardiac impairments to better individualize treatment.

METHODS AND RESULTS

Patients with HFpEF (n = 398) underwent comprehensive echocardiography and invasive cardiopulmonary exercise testing. Patients were categorized as low BCPO reserve (n = 199, < median of 1.57 W) or preserved BCPO reserve (n = 199). As compared to those with preserved BCPO reserve, those with low reserve were older and leaner, with more atrial fibrillation, higher N-terminal pro-B-type natriuretic peptide levels, worse renal function, more impaired left ventricular (LV) global longitudinal strain, worse LV diastolic function and right ventricular longitudinal function. Cardiac filling pressures and pulmonary artery pressures at rest were higher in low BCPO reserve, but central pressures were similar during exercise to those with preserved BCPO reserve. Exertional systemic and pulmonary vascular resistances were higher and exercise capacity was more impaired in those with low BCPO reserve. Reduced BCPO reserve was associated with increased risk for the composite endpoint of heart failure hospitalization or death over 2.9 (interquartile range 0.9-4.5) years of follow-up (hazard ratio 2.77, 95% confidence interval 1.73-4.42, p < 0.0001).

CONCLUSIONS

Inability to enhance BCPO during exercise is associated with more advanced HFpEF, increased systemic and pulmonary vascular resistance, reduced exercise capacity and increased adverse events in patients with HFpEF. Novel therapies that enhance biventricular reserve merit further investigation for patients with this phenotype.

The prognostic value of cardiopulmonary exercise testing and HFA-PEFF in patients with unexplained dyspnea and preserved left ventricular ejection fraction

BACKGROUND

HFA-PEFF and cardiopulmonary exercise testing (CPET) are comprehensive diagnostic tools for heart failure with preserved ejection fraction (HFpEF). We aimed to investigate the incremental prognostic value of CPET for the HFA-PEFF score among patients with unexplained dyspnea with preserved ejection fraction (EF).

METHODS

Consecutive patients with dyspnea and preserved EF (n = 292) were enrolled between August 2019 and July 2021. All patients underwent CPET and comprehensive echocardiography, including two-dimensional speckle tracking echocardiography in the left ventricle, left atrium and right ventricle. The primary outcome was defined as a composite cardiovascular event including cardiovascular-related mortality, acute recurrent heart failure hospitalization, urgent repeat revascularization/myocardial infarction or any hospitalization due to cardiovascular events.

RESULTS

The mean age was 58 ± 14.5 years, and 166 (56.8%) participants were male. The study population was divided into three groups based on the HFA-PEFF score: < 2 (n = 81), 2-4 (n = 159), and ≥ 5 (n = 52). HFA-PEFF score ≥ 5, VE/VCO₂ slope, peak systolic strain rate of the left atrium and resting diastolic blood pressure were independently associated with composite cardiovascular events. Furthermore, the addition of VE/VCO₂ and HFA-PEFF to the base model showed incremental prognostic value for predicting composite cardiovascular events (C-statistic 0.898; integrated discrimination improvement 0.129, p = 0.032; net reclassification improvement 1.043, p ≤0.001).

CONCLUSIONS

CPET could be exploited for the HFA-PEFF approach in terms of incremental prognostic value and diagnosis among patients with unexplained dyspnea with preserved EF.

Combining cardiopulmonary exercise testing with echocardiography: a multiparametric approach to the cardiovascular and cardiopulmonary systems

Exercise intolerance is a prominent feature of several cardiovascular conditions. However, the physical effort requires the intertwined adaptation of several factors, namely the cardiovascular system, the lungs, and peripheral muscles. Several abnormalities in each domain may be present in a given patient. Cardiopulmonary exercise testing (CPET) has been used to investigate metabolic and ventilatory alterations responsible for exercise intolerance but does not allow for direct evaluation of cardiovascular function. However, this can readily be obtained by concomitant exercise-stress echocardiography (ESE). The combined CPET-ESE approach allows for precise and thorough phenotyping of the pathophysiologic mechanisms underpinning exercise intolerance. Thus, it can be used to refine the diagnostic workup of patients with dyspnoea of unknown origin, as well as improve risk stratification and potentially guide the therapeutic approach in specific conditions, including left and right heart failure or valvular heart disease. However, given its hitherto sporadic use, both the conceptual and technical aspects of CPET-ESE are often poorly known by the clinician. Improving knowledge in this field could significantly aid in anticipating individual disease trajectories and tailoring treatment strategies accordingly. Therefore, we designed this review to revise the pathophysiologic correlates of exercise intolerance, the practical principles of the combined CPET-ESE examination, and its main applications according to current literature.

Safety and effectiveness of standardized exercise training in patients with pulmonary hypertension associated with heart failure with preserved ejection fraction (TRAIN-HFpEF-PH): study protocol for a randomized controlled multicenter trial

BACKGROUND

Left heart failure (HF) is characterized by an elevation in left-sided filling pressures, causing symptoms of dyspnea, impairing exercise capacity, and leading to pulmonary venous congestion and secondary pulmonary hypertension (PH). There is an increased incidence of PH associated with left heart disease, particularly with heart failure with preserved ejection fraction (HFpEF-PH). Treatment possibilities in HFpEF-PH are non-specific and very limited, thus additional pharmacological and non-pharmacological therapeutic strategies are needed. Various types of exercise-based rehabilitation programs have been shown to improve exercise capacity and quality of life (QoL) of HF and PH patients. However, no study focused on exercise training in the population of HFpEF-PH. This study is designed to investigate whether a standardized low-intensity exercise and respiratory training program is safe and may improve exercise capacity, QoL, hemodynamics, diastolic function, and biomarkers in patients with HFpEF-PH.

METHODS

A total of 90 stable patients with HFpEF-PH (World Health Organization functional class II-IV) will be randomized (1:1) to receive a 15-week specialized low-intensity rehabilitation program, including exercise and respiratory therapy and mental gait training, with an in-hospital start, or standard care alone. The primary endpoint of the study is a change in 6-min walk test distance; secondary endpoints are changes in peak exercise oxygen uptake, QoL, echocardiographic parameters, prognostic biomarkers, and safety parameters.

DISCUSSION

To date, no study has investigated the safety and efficacy of exercising specifically in the HFpEF-PH population. We believe that a randomized controlled multicenter trial, which protocol we are sharing in this article, will add important knowledge about the potential utility of a specialized low-intensity exercise and respiratory training program for HFpEF-PH and will be valuable in finding optimal treatment strategies for these patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05464238. July 19, 2022.

Diagnostic value of expired gas analysis in heart failure with preserved ejection fraction

Cardiopulmonary exercise testing (CPET) may potentially differentiate heart failure (HF) with preserved ejection fraction (HFpEF) from noncardiac causes of dyspnea (NCD). While contemporary guidelines for HF recommend using CPET for identifying causes of unexplained dyspnea, data supporting this practice are limited. This study aimed to determine the diagnostic value of expired gas analysis to distinguish HFpEF from NCD. Exercise stress echocardiography with simultaneous expired gas analysis was performed in patients with HFpEF (n = 116) and those with NCD (n = 112). Participants without dyspnea symptoms were also enrolled as controls (n = 26). Exercise capacity was impaired in patients with HFpEF than in controls and those with NCD, evidenced by lower oxygen consumption (VO₂), but there was a substantial overlap between HFpEF and NCD. Receiver operating characteristic curve analyses showed modest diagnostic abilities of expired gas analysis data in differentiating individuals with HFpEF from the controls; however, none of these variables clearly differentiated between HFpEF and NCD (all areas under the curve < 0.61). Expired gas analysis provided objective assessments of exercise capacity; however, its diagnostic value in identifying HFpEF among patients with symptoms of exertional dyspnea was modest.

Rate-Adaptive Atrial Pacing for Heart Failure With Preserved Ejection Fraction: The RAPID-HF Randomized Clinical Trial

Importance

Reduced heart rate during exercise is common and associated with impaired aerobic capacity in heart failure with preserved ejection fraction (HFpEF), but it remains unknown if restoring exertional heart rate through atrial pacing would be beneficial.

Objective

To determine if implanting and programming a pacemaker for rate-adaptive atrial pacing would improve exercise performance in patients with HFpEF and chronotropic incompetence.

Design, Setting, and Participants

Single-center, double-blind, randomized, crossover trial testing the effects of rate-adaptive atrial pacing in patients with symptomatic HFpEF and chronotropic incompetence at a tertiary referral center (Mayo Clinic) in Rochester, Minnesota. Patients were recruited between 2014 and 2022 with 16-week follow-up (last date of follow-up, May 9, 2022). Cardiac output during exercise was measured by the acetylene rebreathe technique.

Interventions

A total of 32 patients were recruited; of these, 29 underwent pacemaker implantation and were randomized to atrial rate responsive pacing or no pacing first for 4 weeks, followed by a 4-week washout period and then crossover for an additional 4 weeks.

Main Outcomes and Measures

The primary end point was oxygen consumption (V̇o2) at anaerobic threshold (V̇o2,AT); secondary end points were peak V̇o2, ventilatory efficiency (V̇e/V̇co2 slope), patient-reported health status by the Kansas City Cardiomyopathy Questionnaire Overall Summary Score (KCCQ-OSS), and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels.

Results

Of the 29 patients randomized, the mean age was 66 years (SD, 9.7) and 13 (45%) were women. In the absence of pacing, peak V̇o2 and V̇o2 at anaerobic threshold (V̇o2,AT) were both correlated with peak exercise heart rate (r = 0.46-0.51, P < .02 for both). Pacing increased heart rate during low-level and peak exercise (16/min [95% CI, 10 to 23], P < .001; 14/min [95% CI, 7 to 21], P < .001), but there was no significant change in V̇o2,AT (pacing off, 10.4 [SD, 2.9] mL/kg/min; pacing on, 10.7 [SD, 2.6] mL/kg/min; absolute difference, 0.3 [95% CI, -0.5 to 1.0] mL/kg/min; P = .46), peak V̇o2, minute ventilation (V̇e)/carbon dioxide production (V̇co2) slope, KCCQ-OSS, or NT-proBNP level. Despite the increase in heart rate, atrial pacing had no significant effect on cardiac output with exercise, owing to a decrease in stroke volume (-24 mL [95% CI, -43 to -5 mL]; P = .02). Adverse events judged to be related to the pacemaker device were observed in 6 of 29 participants (21%).

Conclusions and Relevance

In patients with HFpEF and chronotropic incompetence, implantation of a pacemaker to enhance exercise heart rate did not result in an improvement in exercise capacity and was associated with increased adverse events.

Trial Registration

ClinicalTrials.gov Identifier: NCT02145351.

Heart Failure With Preserved Ejection Fraction: A Review

IMPORTANCE

Heart failure with preserved ejection fraction (HFpEF), defined as HF with an EF of 50% or higher at diagnosis, affects approximately 3 million people in the US and up to 32 million people worldwide. Patients with HFpEF are hospitalized approximately 1.4 times per year and have an annual mortality rate of approximately 15%.

OBSERVATIONS

Risk factors for HFpEF include older age, hypertension, diabetes, dyslipidemia, and obesity. Approximately 65% of patients with HFpEF present with dyspnea and physical examination, chest radiographic, echocardiographic, or invasive hemodynamic evidence of HF with overt congestion (volume overload) at rest. Approximately 35% of patients with HFpEF present with "unexplained" dyspnea on exertion, meaning they do not have clear physical, radiographic, or echocardiographic signs of HF. These patients have elevated atrial pressures with exercise as measured with invasive hemodynamic stress testing or estimated with Doppler echocardiography stress testing. In unselected patients presenting with unexplained dyspnea, the H2FPEF score incorporating clinical (age, hypertension, obesity, atrial fibrillation status) and resting Doppler echocardiographic (estimated pulmonary artery systolic pressure or left atrial pressure) variables can assist with diagnosis (H2FPEF score range, 0-9; score >5 indicates more than 95% probability of HFpEF). Specific causes of the clinical syndrome of HF with normal EF other than HFpEF should be identified and treated, such as valvular, infiltrative, or pericardial disease. First-line pharmacologic therapy consists of sodium-glucose cotransporter type 2 inhibitors, such as dapagliflozin or empagliflozin, which reduced HF hospitalization or cardiovascular death by approximately 20% compared with placebo in randomized clinical trials. Compared with usual care, exercise training and diet-induced weight loss produced clinically meaningful increases in functional capacity and quality of life in randomized clinical trials. Diuretics (typically loop diuretics, such as furosemide or torsemide) should be prescribed to patients with overt congestion to improve symptoms. Education in HF self-care (eg, adherence to medications and dietary restrictions, monitoring of symptoms and vital signs) can help avoid HF decompensation.

CONCLUSIONS AND RELEVANCE

Approximately 3 million people in the US have HFpEF. First-line therapy consists of sodium-glucose cotransporter type 2 inhibitors, exercise, HF self-care, loop diuretics as needed to maintain euvolemia, and weight loss for patients with obesity and HFpEF.

Recumbent Ergometer vs Treadmill Cardiopulmonary Exercise Test in HFpEF: Implications for Chronotropic Response and Exercise Capacity

BACKGROUND

Cardiopulmonary exercise testing (CPET) can identify mechanisms of exercise intolerance in heart failure with preserved ejection fraction (HFpEF), but exercise modalities with differing body positions (eg, recumbent ergometer, treadmill) are broadly used. In this study, we aimed to determine whether body position affects CPET parameters in patients with HFpEF.

METHODS

Subjects with stable HFpEF (n = 23) underwent noninvasive treadmill CPET, followed by an invasive recumbent-cycle ergometer CPET within 3 months. A comparison group undergoing similar studies included healthy subjects (n = 5) and subjects with pulmonary arterial hypertension (n = 6).

RESULTS

The peak oxygen consumption (VO₂peak) and peak heart rate were significantly lower in the recumbent vs the upright position (10.1 vs 13.1 mL/kg/min [Δ-3 mL/kg/min]; P < 0.001; and 95 vs 113 bpm [Δ-18 bpm]; P < 0.001, respectively). No significant differences were found in the minute ventilation to carbon dioxide production ratio, end-tidal pressure of carbon dioxide or respiratory exchange ratio. A similar pattern was observed in the comparison groups.

CONCLUSIONS

Compared to recumbent ergometer, treadmill CPET revealed higher VO₂peak and peak heart rate response. When determining chronotropic incompetence to adjust beta-blocker administration in HFpEF, body position should be taken into account.

Cardiopulmonary test as a component in the diagnostic algorithm for heart failure with preserved left ventricular ejection fraction in patients with atrial fibrillation

Objective: to evaluate the role of cardiopulmonary test in the diagnosis of heart failure with preserved ejection fraction in patients with atrial fibrillation. Material and Methods: 138 patients with atrial fibrillation were included in our study. Using HFA-PEFF algorithm (algorithm for diagnosis of heart failure with preserved left ventricular ejection fraction) all patients were initially divided into 3 groups: low probability of heart failure - 23 patients, intermediate probability - 96 and high probability - 19 patients. The stress-test allowed to precisely assess of patients at intermediate risk and finally form the groups: Group 1 without heart failure, 85 patients (61.6%); Group 2 patients with heart failure and preserved ejection fraction, 53 patients (38.4%). The next diagnostic stage was cardiopulmonary test. Results: during CPT, the maximum anaerobic exercise threshold was 6.8 and 4.85 METS for the first and second groups, respectively (p0.001), reflecting lower exercise tolerance in the second group of patients. Analysis of variance (ANOVA) demonstrated a statistically significant increase in pro-BNP levels with a decrease in peak VO2 (p0.001). Also, analysis of variance demonstrated a significant statistical difference with respect to systolic pulmonary artery pressure in the subgroups with severely, moderately reduced oxygen consumption and in the group with normal peak VO2 (p=0.01). ROC analysis determined a peak VO2 of 20 ml/kg/min, above which the HFA-PEFF algorithm was unlikely to detect heart failure (AUC 0.73; confidence interval 0.65-0.82; p=0.043; sensitivity 85%; specificity 51%). Conclusion: Cardiopulmonary test is a reliable instrumental noninvasive method of investigation in the diagnosis of heart failure with preserved ejection fraction. Keywords: atrial fibrillation; chronic heart failure; cardiopulmonary test; ergospirometry

Phenomapping in heart failure with preserved ejection fraction: insights, limitations, and future directions

Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous entity with complex pathophysiology and manifestations. Phenomapping is the process of applying statistical learning techniques to patient data to identify distinct subgroups based on patterns in the data. Phenomapping has emerged as a technique with potential to improve the understanding of different HFpEF phenotypes. Phenomapping efforts have been increasing in HFpEF over the past several years using a variety of data sources, clinical variables, and statistical techniques. This review summarizes methodologies and key takeaways from these studies, including consistent discriminating factors and conserved HFpEF phenotypes. We argue that phenomapping results to date have had limited implications for clinical care and clinical trials, given that the phenotypes, as currently described, are not reliably identified in each study population and may have significant overlap. We review the inherent limitations of aggregating and utilizing phenomapping results. Lastly, we discuss potential future directions, including using phenomapping to optimize the likelihood of clinical trial success or to drive discovery in mechanisms of the disease process of HFpEF.

Efficacy and safety of inorganic nitrate/nitrite supplementary therapy in heart failure with preserved ejection fraction

Background

Approximately half of patients with heart failure have a preserved ejection fraction (HFpEF). To date, only SGLT-2i, ARNi, and MRAs treatments have been shown to be effective for HFpEF. Exercise intolerance is the primary clinical feature of HFpEF. The aim of this meta-analysis was to explore the effect of inorganic nitrate/nitrite supplementary therapy on the exercise capacity of HFpEF patients.

Methods

We searched PubMed, Embase, Cochrane Library, OVID, and Web of Science for eligible studies for this meta-analysis. The primary outcomes were peak oxygen consumption (peak VO₂), exercise time, and respiratory exchange ratio (RER) during exercise. The secondary outcomes were cardiac output, heart rate, systolic blood pressure, diastolic blood pressure, mean arterial pressure, and systemic vascular resistance during rest and exercise, respectively.

Results

A total of eight randomized-controlled trials were enrolled for this meta-analysis. We found no benefit of inorganic nitrate/nitrite on exercise capacity in patients with HFpEF. Inorganic nitrate/nitrite compared to placebo, did not significantly increased peak VO₂ (MD = 0.361, 95% CI = -0.17 to 0.89, p = 0.183), exercise time (MD = 9.74, 95% CI = -46.47 to 65.95, p = 0.734), and respiratory exchange ratio during exercise (MD = -0.003, 95% CI = -0.036 to 0.029, p = 0.834). Among the six diameters reflecting cardiac and artery hemodynamics, inorganic nitrate/nitrite can lower rest SBP, rest/exercise DBP, rest/exercise MAP, and exercise SVR, but has no effect in cardiac output and heart rate for HFpEF patients.

Conclusion

Our meta-analysis suggested that inorganic nitrate/nitrite supplementary therapy has no benefit in improving the exercise capacity of patients with HFpEF, but can yield a blood pressure lowering effect, especially during exercise.

Central haemodynamic abnormalities and outcome in patients with unexplained dyspnoea

AIMS

Little data are available regarding prognostic implications of invasive exercise testing in heart failure with preserved ejection fraction (HFpEF). The present study aimed to investigate whether rest and exercise central haemodynamic abnormalities are associated with adverse clinical outcomes in patients with dyspnea.

METHODS AND RESULTS

Patients with exertional dyspnoea and ejection fraction ≥50% (n = 764) underwent invasive exercise testing and follow-up for heart failure hospitalization or death. There were 117 patients with events over a median follow-up of 2.7 (interquartile range 0.5-4.6) years. Among patients with normal resting pulmonary artery wedge pressure (PAWP) (<15 mmHg, n = 380 [50%]), increased exercise PAWP (≥25 mmHg) was present in 187 (24% of cohort) and was associated with 2.4-fold higher risk of events compared to those with normal exercise PAWP (<25 mmHg, n = 193 [25%]) (hazard ratio [HR] 2.44; 95% confidence interval [CI] 1.11-5.36; p = 0.03), while patients with elevated resting PAWP (≥15 mmHg, n = 384 [50%]) displayed even higher risk compared to HFpEF with normal resting PAWP (HR 2.24; 95% CI 1.38-3.65; p = 0.001). Similar findings were observed for rest/exercise right atrial pressure, and rest/exercise pulmonary artery pressures. Higher peak oxygen consumption was associated with decreased risk of events, and this relationship was solely explained by exercise cardiac output. In a multivariable-adjusted Cox model, each 1 standard deviation (SD) increase in exercise PAWP was associated with a 41% greater hazard of events (HR 1.41; 95% CI 1.13-1.76; p = 0.002), while each 1 SD decrease in exercise cardiac output was associated with a 37% increased risk (HR 0.63; 95% CI 0.47-0.83; p = 0.001).

CONCLUSIONS

Haemodynamic abnormalities currently used for diagnosis of HFpEF are associated with increased risk for adverse events. Treatments that reduce central pressures while improving cardiac output reserve may offer greatest benefit to improve outcomes in HFpEF.

Challenging the Hemodynamic Hypothesis in Heart Failure With Preserved Ejection Fraction: Is Exercise Capacity Limited by Elevated Pulmonary Capillary Wedge Pressure?

BACKGROUND

Exercise intolerance is a defining characteristic of heart failure with preserved ejection fraction (HFpEF). A marked rise in pulmonary capillary wedge pressure (PCWP) during exertion is pathognomonic for HFpEF and is thought to be a key cause of exercise intolerance. If true, acutely lowering PCWP should improve exercise capacity. To test this hypothesis, we evaluated peak exercise capacity with and without nitroglycerin to acutely lower PCWP during exercise in patients with HFpEF.

METHODS

Thirty patients with HFpEF (70±6 years of age; 63% female) underwent 2 bouts of upright, seated cycle exercise dosed with sublingual nitroglycerin or placebo control every 15 minutes in a single-blind, randomized, crossover design. PCWP (right heart catheterization), oxygen uptake (breath × breath gas exchange), and cardiac output (direct Fick) were assessed at rest, 20 Watts (W), and peak exercise during both placebo and nitroglycerin conditions.

RESULTS

PCWP increased from 8±4 to 35±9 mm Hg from rest to peak exercise with placebo. With nitroglycerin, there was a graded decrease in PCWP compared with placebo at rest (-1±2 mm Hg), 20W (-5±5 mm Hg), and peak exercise (-7±6 mm Hg; drug × exercise stage P=0.004). Nitroglycerin did not affect oxygen uptake at rest, 20W, or peak (placebo, 1.34±0.48 versus nitroglycerin, 1.32±0.46 L/min; drug × exercise P=0.984). Compared with placebo, nitroglycerin lowered stroke volume at rest (-8±13 mL) and 20W (-7±11 mL), but not peak exercise (0±10 mL).

CONCLUSIONS

Sublingual nitroglycerin lowered PCWP during submaximal and maximal exercise. Despite reduction in PCWP, peak oxygen uptake was not changed. These results suggest that acute reductions in PCWP are insufficient to improve exercise capacity, and further argue that high PCWP during exercise is not by itself a limiting factor for exercise performance in patients with HFpEF.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04068844.

Exercise-induced changes in pulmonary artery wedge pressure in adults post-Fontan versus heart failure with preserved ejection fraction and non-cardiac dyspnoea

AIMS

Despite their universal predisposition, diagnosing diastolic dysfunction in patients post-Fontan palliation is challenging. Our aim was to compare exercise haemodynamics between adults post-Fontan and patients with heart failure with preserved ejection fraction (HFpEF) and non-cardiac dyspnoea (NCD).

METHODS AND RESULTS

Twenty-four adults (age ≥18 years) post-Fontan palliation with resting and exercise pulmonary artery wedge pressure (PAWP) measured during supine biking were identified. Forty-eight patients with HFpEF and 48 with NCD diagnosed at catheterization were selected for comparison. Mean age for Fontan patients was 30.3 ± 7.5 years; median ventricular ejection fraction was 52.5% (45-55.8), being <50% in 37.5%. Resting PAWP among Fontan patients was 10.2 ± 3.5 mmHg (>12 mmHg in 25%); PAWP was lower in Fontan patients than in HFpEF but higher than NCD. During exercise, PAWP was lower in the Fontan group than HFpEF (22.5 mmHg [19.3-28] vs. 28.2 ± 6.3; p = 0.0006) but higher than NCD (11.2 ± 4.2, p ≤ 0.0001). However, there were no differences in ΔPAWP/ΔQs between Fontan and HFpEF patients (4.0 [2.1-7.3] vs. 2.7 [1.6-4.4]; p = 0.10) with the ratio being higher post-Fontan than in NCD (0.6 [0.2-1.2]; p < 0.0001). ΔPAWP/ΔQs remained similar between HFpEF and Fontan patients even when those with ejection fraction <50% were excluded (2.7 [1.6-4.4] vs. 2.7 [1.0-5.8]; p = 0.97).

CONCLUSION

There were no differences in ΔPAWP/ΔQs ratios between post-Fontan and HFpEF patients, supporting markedly abnormal single ventricle compliance despite lower resting and exercise PAWP. Therefore, exercise invasive haemodynamics may represent a novel tool for the diagnosis of diastolic dysfunction in Fontan patients.

Device therapy with interatrial shunt devices for heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction is responsible for half of all heart failure and confers substantial morbidity and mortality, and yet to date, there have been no effective pharmacologic interventions. Although the pathophysiology is complex, the primary aetiology of exercise intolerance is due to an elevated left atrial pressure, particularly with exercise. In this context, device-based therapy has become a focus. Several companies have developed techniques to percutaneously create an iatrogenic left to right shunt at the atrial level, thereby reducing left atrial pressure and reducing transmitted pressures to the pulmonary circulation and reducing pulmonary congestion. In this review, we explore the pathophysiology, evidence base, benefits, and considerations of these devices and their place in the therapeutic landscape of heart failure with preserved ejection fraction.

Determinants of exercise capacity in patients with heart failure without left ventricular hypertrophy

BACKGROUND

Determinants of exercise intolerance in a phenotype of heart failure with preserved ejection fraction (HFpEF) with normal left ventricular (LV) structure have not been fully elucidated.

METHODS

Cardiopulmonary exercise testing and exercise-stress echocardiography were performed in 44 HFpEF patients without LV hypertrophy. Exercise capacity was determined by peak oxygen consumption (peak VO₂). Doppler-derived cardiac output (CO), transmitral E velocity, systolic (LV-s') and early diastolic mitral annular velocities (e'), systolic pulmonary artery (PA) pressure (SPAP), tricuspid annular plane systolic excursion (TAPSE), and peak systolic right ventricular (RV) free wall velocity (RV-s') were measured at rest and exercise. E/e' and TAPSE/SPAP were used as an LV filling pressure parameter and RV-PA coupling, respectively.

RESULTS

During exercise, CO, LV-s', RV-s', e', and SPAP were significantly increased (p < 0.05 for all), whereas E/e' remained unchanged and TAPSE/SPAP was significantly reduced (p < 0.001). SPAP was higher and TAPSE/SPAP was lower at peak exercise in patients showing lower-half peak VO₂. In univariable analyses, LV-s' (R = 0.35, p = 0.022), SPAP (R = -0.40, p = 0.008), RV-s' (R = 0.47, p = 0.002), and TAPSE/SPAP (R = 0.42, p = 0.005) were significantly correlated with peak VO₂. In multivariable analyses, not only SPAP, but also TAPSE/SPAP independently determined peak VO₂ even after the adjustment for clinically relevant parameters.

CONCLUSIONS

In HFpEF patients without LV hypertrophy, altered RV-PA coupling by exercise could be associated with exercise intolerance, which might not be caused by elevated LV filling pressure.

The effect of exercise training and physiotherapy on left and right heart function in heart failure with preserved ejection fraction: a systematic literature review

The impact of exercise training and physiotherapy on heart function and pulmonary circulation parameters in heart failure with preserved ejection fraction (HFpEF) patients is uncertain. Hence, we performed a systematic review of published trials studying physical training in HFpEF population, with a focus on exercise and physiotherapy effect on left ventricular (LV), right ventricular (RV) morphological, functional, and pulmonary circulation parameters. We searched Cochrane Library and MEDLINE/PubMed for trials that evaluated the effect of exercise training and/or physiotherapy in adult HFpEF patients (defined as LVEF ≥ 45%), including publications until March 2021. Our systematic review identified eighteen articles (n = 418 trained subjects, 4 to 52 weeks of training) and covered heterogeneous trials with various populations, designs, methodologies, and interventions. Five of twelve trials revealed a significant reduction of mitral E/e' ratio after the training (- 1.2 to - 4.9). Seven studies examined left atrial volume index; three of them showed its decrease (- 3.7 to - 8 ml/m²). Findings were inconsistent regarding improvement of cardiac output, E/A ratio, and E wave DecT and uncertain for RV function and pulmonary hypertension parameters. For now, no reliable evidence about rehabilitation effect on HFpEF cardiac mechanisms is available. There are some hypotheses generating findings on potential positive effects to parameters of LV filling pressure (E/e'), left atrium size, cardiac output, and RV function. This encourages a broader and more complex assessment of parameters reflecting cardiac function in future HFpEF exercise training studies.

Skeletal muscle phenotypic switching in heart failure with preserved ejection fraction

Background

Skeletal muscle (SkM) phenotypic switching is associated with exercise intolerance in heart failure with preserved ejection fraction (HFpEF). Patients with HFpEF have decreased type-1 oxidative fibers and mitochondrial dysfunction, indicative of impaired oxidative capacity. The SAUNA (SAlty drinking water/Unilateral Nephrectomy/Aldosterone) mice are commonly used in HFpEF pre-clinical studies and demonstrate cardiac, lung, kidney, and white adipose tissue impairments. However, the SkM (specifically the oxidative-predominant, soleus muscle) has not been described in this preclinical HFpEF model. We sought to characterize the soleus skeletal muscle in the HFpEF SAUNA mice and investigate its translational potential.

Methods

HFpEF was induced in mice by uninephrectomy, d-aldosterone or saline (Sham) infusion by osmotic pump implantation, and 1% NaCl drinking water was given for 4 weeks. Mice were euthanized, and the oxidative-predominant soleus muscle was collected. We examined fiber composition, fiber cross-sectional area, capillary density, and fibrosis. Molecular analyses were also performed. To investigate the clinical relevance of this model, the oxidative-predominant, vastus lateralis muscle from patients with HFpEF was biopsied and examined for molecular changes in mitochondrial oxidative phosphorylation, vasculature, fibrosis, and inflammation.

Results

Histological analyses demonstrated a reduction in the abundance of oxidative fibers, type-2A fiber atrophy, decreased capillary density, and increased fibrotic area in the soleus muscle of HFpEF mice compared to Sham. Expression of targets of interest such as a reduction in mitochondrial oxidative-phosphorylation genes, increased VEGF-α and an elevated inflammatory response was also seen. The histological and molecular changes in HFpEF mice are consistent and comparable with changes seen in the oxidative-predominant SkM of patients with HFpEF.

Conclusion

The HFpEF SAUNA model recapitulates the SkM phenotypic switching seen in HFpEF patients. This model is suitable and relevant to study SkM phenotypic switching in HFpEF.

Hemodynamic Assessment in Heart Failure with Preserved Ejection Fraction

Heart failure (HF) with preserved ejection fraction (HFpEF) is characterized by an inability of the heart to perfuse the body without pathologic increases in filling pressure at rest or during exertion. Right heart catheterization provides direct assessment for HF, providing the most robust and direct method to evaluate the central hemodynamic abnormalities, and serves as the gold standard to confirm or refute the presence of HFpEF. This article reviews current understanding of the best practices in the performance and interpretation of hemodynamic assessment, relates important pathophysiologic concepts to clinical care, and discusses current and evidence-based applications of hemodynamics in HFpEF.

Mitochondrial oxidative stress contributes to diastolic dysfunction through impaired mitochondrial dynamics

Diastolic dysfunction (DD) underlies heart failure with preserved ejection fraction (HFpEF), a clinical syndrome associated with aging that is becoming more prevalent. Despite extensive clinical studies, no effective treatment exists for HFpEF. Recent findings suggest that oxidative stress contributes to the pathophysiology of DD, but molecular mechanisms underpinning redox-sensitive cardiac remodeling in DD remain obscure. Using transgenic mice with mitochondria-targeted NOX4 overexpression (Nox4TG618) as a model, we demonstrate that NOX4-dependent mitochondrial oxidative stress induces DD in mice as measured by increased E/E', isovolumic relaxation time, Tau Glantz and reduced dP/dtmin while EF is preserved. In Nox4TG618 mice, fragmentation of cardiomyocyte mitochondria, increased DRP1 phosphorylation, decreased expression of MFN2, and a higher percentage of apoptotic cells in the myocardium are associated with lower ATP-driven and maximal mitochondrial oxygen consumption rates, a decrease in respiratory reserve, and a decrease in citrate synthase and Complex I activities. Transgenic mice have an increased concentration of TGFβ and osteopontin in LV lysates, as well as MCP-1 in plasma, which correlates with a higher percentage of LV myocardial periostin- and ACTA2-positive cells compared with wild-type mice. Accordingly, the levels of ECM as measured by Picrosirius Red staining as well as interstitial deposition of collagen I are elevated in the myocardium of Nox4TG618 mice. The LV tissue of Nox4TG618 mice also exhibited increased ICaL current, calpain 2 expression, and altered/disrupted Z-disc structure. As it pertains to human pathology, similar changes were found in samples of LV from patients with DD. Finally, treatment with GKT137831, a specific NOX1 and NOX4 inhibitor, or overexpression of mCAT attenuated myocardial fibrosis and prevented DD in the Nox4TG618 mice. Together, our results indicate that mitochondrial oxidative stress contributes to DD by causing mitochondrial dysfunction, impaired mitochondrial dynamics, increased synthesis of pro-inflammatory and pro-fibrotic cytokines, activation of fibroblasts, and the accumulation of extracellular matrix, which leads to interstitial fibrosis and passive stiffness of the myocardium. Further, mitochondrial oxidative stress increases cardiomyocyte Ca2+ influx, which worsens CM relaxation and raises the LV filling pressure in conjunction with structural proteolytic damage.

New perspective on fatigue in hemodialysis patients with preserved ejection fraction: diastolic dysfunction : Fatigue and diastolic dysfunction

The relationship between diastolic dysfunction and fatigue in hemodialysis patients with preserved ejection fraction is unknown. In this context, the objective of this study is to assess fatigue using the relevant scales and to demonstrate its relationship with diastolic dysfunction. The patients who underwent hemodialysis were evaluated prospectively. Patients' fatigue was assessed using the Visual Analogue Scale to Evaluate Fatigue Severity (VAS-F). The echocardiographic works were performed as recommended in the American Society of Echocardiography guidelines. A total of 94 patients [mean age 64.7 ± 13.5 years, 54 males (57.4%)] were included in the study. The median VAS-F score of these patients was 68.5 (33.25-91.25), and they were divided into two groups according to this value. Peak myocardial velocities during early diastole (e') and tricuspid annular plane systolic excursion (TAPSE) values were found to be significantly lower in the group with high VAS-F scores, whereas the early diastolic flow velocities (E)/e' ratio and pulmonary artery peak systolic pressures (PAP) were found to be significantly higher (p < 0.05, for all). E/e' ratio (r 0.311, p 0.002) and PAP (r 0.281, p 0.006) values were found to be positively correlated with the VAS-F score, as opposed to the TAPSE (r - 0.257, p 0.012) and e' (r - 0.303, p 0.003) values, which were found to be negatively correlated with the VAS-F score. High fatigue scores in hemodialysis patients may be associated with diastolic dysfunction. In addition, in our study, we determined the correlation of VAS-F score with E/e' ratio, PAP and TAPSE.

Modern Approaches for the Treatment of Heart Failure: Recent Advances and Future Perspectives

Heart failure (HF) is a progressively deteriorating medical condition that significantly reduces both the patients’ life expectancy and quality of life. Even though real progress was made in the past decades in the discovery of novel pharmacological treatments for HF, the prevention of premature deaths has only been marginally alleviated. Despite the availability of a plethora of pharmaceutical approaches, proper management of HF is still challenging. Thus, a myriad of experimental and clinical studies focusing on the discovery of new and provocative underlying mechanisms of HF physiopathology pave the way for the development of novel HF therapeutic approaches. Furthermore, recent technological advances made possible the development of various interventional techniques and device-based approaches for the treatment of HF. Since many of these modern approaches interfere with various well-known pathological mechanisms in HF, they have a real ability to complement and or increase the efficiency of existing medications and thus improve the prognosis and survival rate of HF patients. Their promising and encouraging results reported to date compel the extension of heart failure treatment beyond the classical view. The aim of this review was to summarize modern approaches, new perspectives, and future directions for the treatment of HF.

Cardiovascular Mechanisms of Exercise Intolerance in Older Patients with Heart Failure

Exercise intolerance, measured by peak oxygen consumption (V̇O2), is a hallmark feature of heart failure (HF). The effect is compounded in the elderly HF patient by aging-associated changes such as a reduction in lean muscle mass, an increase in adiposity, and a reduction in maximal heart rate and peripheral blood flow with exercise. There is a non-linear reduction in peak V̇O2 with age that accelerates in the later decades of life. Peak V̇O2 is further reduced due to central and peripheral maladaptation from HF. Central mechanisms include impaired peak heart rate, stroke volume, contractility, increased filling pressures, and a blunted vasodilatory response. Peripheral mechanisms include endothelial dysfunction, reduced blood flow to muscles, and impaired skeletal muscle oxidative capacity. This review presents a focused update on mechanisms leading to impaired aerobic capacity in older HF patients.

Kinetic energy of left ventricular blood flow across heart failure phenotypes and in subclinical diastolic dysfunction

BACKGROUND

Kinetic energy (KE) of intracardiac blood flow reflects myocardial work spent on accelerating blood and provides a mechanistic window into diastolic filling dynamics. Diastolic dysfunction may represent an early stage in the development of heart failure (HF). Here we evaluated the hemodynamic effects of impaired diastolic function in subjects with and without HF, testing the hypothesis that left ventricular KE differs between controls, subjects with subclinical diastolic dysfunction (SDD), and HF patients.

METHODS

We studied 77 subjects (16 controls, 20 subjects with SDD, 16 HFpEF, 9 HFmrEF, and 16 HFrEF patients, age- and sex-matched at the group level). Cardiac magnetic resonance at 1.5T included intracardiac 4D flow and cine imaging. Left ventricular KE was calculated as 0.5*m*v².

RESULTS

Systolic KE was similar between groups (p>0.4), also after indexing to stroke volume (p=0.25), and was primarily driven by ventricular emptying rate (p<0.0001, R²=0.52). Diastolic KE was higher in heart failure patients than controls (p<0.05) but similar between SDD and HFpEF (p>0.18), correlating with inflow conditions (E-wave velocity, p<0.0001, R²=0.24) and end-diastolic volume (p=0.0003, R²=0.17) but not with average e' (p=0.07).

CONCLUSIONS

Diastolic KE differs between controls and heart failure, suggesting more work is spent filling the failing ventricle, while systolic KE does not differentiate between well-matched groups with normal ejection fraction even in the presence of relaxation abnormalities and heart failure. Mechanistically, KE reflects the acceleration imparted on the blood and is driven by variations in ventricular emptying and filling rates, volumes, and heart rate, regardless of underlying pathology.

Clinical course and decision-making in heart failure by preload stress echocardiography: a preliminary study

AIMS

Abnormal left ventricular diastolic response to preload stress can be an early marker of heart failure (HF). The aim of this study was to assess clinical course in patients with HF with preserved ejection fraction (HFpEF) who underwent preload stress echocardiography. In the subgroup analysis, we assessed the prognosis of patients with unstable signs during preload stress classified by treatment strategies.

METHODS AND RESULTS

We prospectively conducted preload stress echocardiographic studies between January 2006 and December 2013 in 211 patients with HFpEF. Fifty-eight patients had abnormal diastolic reserve during preload stress (unstable impaired relaxation: unstable IR). Of 58 patients with unstable IR, 19 patients were assigned to additional therapy by increased or additional therapy and 39 patients were assigned to standard therapy. Composite outcomes were prespecified as the primary endpoint of death and hospitalization for deteriorating HF. During a median period of 6.9 years, 19 patients (33%) reached the composite outcome. Unstable group with standard therapy had significantly shorter event-free survival than stable group. Patients with uptitration of therapy had longer event-free survival than those with standard therapy group after adjustment of laboratory data (hazard ratio, 0.20, 95% confidence interval, 0.05-0.90; P = 0.036); the 10 year event-free survival in patients with and without uptitration of therapy was 93% and 51%, respectively (P = 0.023).

CONCLUSIONS

Patients with unstable sign had significantly shorter event-free survival than patients with stable sign. After additional therapy, the prognosis of patients with unstable signs improved. This technique may impact decision-making for improving their prognosis.

Sex and central obesity in heart failure with preserved ejection fraction

AIMS

Obesity is a risk factor for heart failure with preserved ejection fraction (HFpEF), particularly in women, but the mechanisms remain unclear. The present study aimed to investigate the impact of central adiposity in patients with HFpEF and explore potential sex differences.

METHODS AND RESULTS

A total of 124 women and 105 men with HFpEF underwent invasive haemodynamic exercise testing and rest echocardiography. Central obesity was defined as a waist circumference (WC) ≥88 cm for women and ≥102 cm for men. Exercise-normalized pulmonary capillary wedge pressure (PCWP) responses were evaluated by the ratio of PCWP to workload (PCWP/W) and after normalizing to body weight (PCWL). The prevalence of central obesity (77%) exceeded that of general obesity (62%) defined by body mass index ≥30 kg/m² . Compared to patients without central adiposity, patients with HFpEF and central obesity displayed greater prevalence of diabetes and dyslipidaemia, higher right and left heart filling pressures and pulmonary artery pressures during exertion, and more severely reduced aerobic capacity. Associations between WC and fasting glucose, low-density lipoprotein (LDL) cholesterol, peak workload, and pulmonary artery pressures were observed in women but not in men with HFpEF. Although increased WC was associated with elevated PCWP in both sexes, the association with PCWP/W was observed in women but not in men. The strength of correlation between PCWP/W and WC was more robust in women with HFpEF as compared to men (Meng's test p = 0.0008), and a significant sex interaction was observed in the relationship between PCWL and WC (p for interaction = 0.02).

CONCLUSIONS

Central obesity is even more common than general obesity in HFpEF, and there appear to be important sexual dimorphisms in its relationships with metabolic abnormalities and haemodynamic perturbations, with greater impact in women.

Resting Cardiac Power Predicts Adverse Outcome in Heart Failure Patients With Preserved Ejection Fraction: A Prospective Study

Background

We sought to explore the significance of resting cardiac power/mass in predicting adverse outcome in patients with heart failure with preserved ejection fraction (HFpEF).

Methods

This prospective cohort study included patients with HFpEF and without significant valve disease or right ventricular dysfunction. Cardiac power was normalized to left ventricular (LV) mass and expressed in W/100 g of LV myocardium. Multivariate Cox regression analysis was used to evaluate the association between resting cardiac power/mass and composite endpoint, which included all-cause mortality and heart failure (HF) hospitalization.

Results

A total of 2,089 patients were included in this study. After an average follow-up of 4.4 years, 612 (29.30%) patients had composite endpoint, in which 331 (15.84%) died and 391 (18.72%) experienced HF hospitalization. In multivariate Cox regression analysis, resting power/mass < 0.7 W/m² was independently associated with composite endpoint, all-cause mortality, cardiovascular mortality and HF hospitalization, with hazard ratios (HR) of 1.309 [95% confidence interval (CI): 1.108–1.546, P = 0.002], 1.697 (95%CI: 1.344–2.143, P < 0.001), 2.513 (95%CI: 1.711–3.689, P < 0.001), and 1.294 (95%CI: 1.052–1.592, P = 0.015), respectively. For composite endpoint, cardiovascular mortality and HF hospitalization, the C statistic increased significantly when incorporating resting cardiac power/mass into a model with established risk factors. For composite endpoint, the continuous net reclassification index after adding resting cardiac power/mass in the original model with N-terminal pro-brain natriuretic peptide was 13.1% (95%CI: 2.9–21.6%, P = 0.007), and the integrated discrimination index was 1.9% (95%CI: 0.8–3.2%, P < 0.001).

Conclusion

Resting cardiac power determined by non-invasive echocardiography is independently associated with the risk of adverse outcomes in HFpEF patients and provides incremental prognostic information.

Exercise Testing in HFpEF: an Appraisal Through Diagnosis, Pathophysiology and Therapy A Clinical Consensus Statement of the Heart Failure Association (HFA) and European Association of Preventive Cardiology (EAPC) of the European Society of Cardiology (ESC)

Patients with heart failure with preserved ejection fraction (HFpEF) universally complain of exercise intolerance and dyspnoea as key clinical correlates. Cardiac as well as extracardiac components play a role for the limited exercise capacity, including an impaired cardiac and peripheral vascular reserve, a limitation in mechanical ventilation and/or gas exchange with reduced pulmonary vascular reserve, skeletal muscle dysfunction and iron deficiency/anaemia. Although most of these components can be differentiated and quantified through gas exchange analysis by cardiopulmonary exercise testing (CPET), the information provided by objective measures of exercise performance have not been systematically considered in the recent algorithms/scores for HFpEF diagnosis, neither by European nor US groups. The current Clinical Consensus Statement by the HFA and EAPC Association of the ESC aims at outlining the role of exercise testing and its pathophysiological, clinical and prognostic insights, addressing the implication of a thorough functional evaluation from the diagnostic algorithm to the pathophysiology and treatment perspectives of HFpEF. Along with these goals, we provide a specific analysis on the evidence that CPET is the standard for assessing, quantifying, and differentiating the origin of dyspnoea and exercise impairment and even more so when combined with echo and/or invasive hemodynamic evaluation is here provided. This will lead to improved quality of diagnosis when applying the proposed scores and may also help useful to implement the progressive characterization of the specific HFpEF phenotypes, a critical step toward the delivery of phenotype-specific treatments.