The combined exercise stress echocardiography and cardiopulmonary exercise test for identification of masked heart failure with preserved ejection fraction in patients with hypertension

Challenges in Echocardiography for the Diagnosis and Prognosis of Non-Ischemic Hypertensive Heart Disease

It has been well established that arterial hypertension is considered as a predominant risk factor for the development of cardiovascular diseases. Despite the link between arterial hypertension and cardiovascular diseases, arterial hypertension may directly affect cardiac function, leading to heart failure, mostly with preserved ejection fraction (HFpEF). There are echocardiographic findings indicating hypertensive heart disease (HHD), defined as altered cardiac morphology (left ventricular concentric hypertrophy, left atrium dilatation) and function (systolic or diastolic dysfunction) in patients with persistent arterial hypertension irrespective of the cardiac pathologies to which it contributes, such as coronary artery disease and kidney function impairment. In addition to the classical echocardiographic parameters, novel indices, like speckle tracking of the left ventricle and left atrium, 3D volume evaluation, and myocardial work in echocardiography, may provide more accurate and reproducible diagnostic and prognostic data in patients with arterial hypertension. However, their use is still underappreciated. Early detection of and prompt therapy for HHD will greatly improve the prognosis. Hence, in the present review, we shed light on the role of echocardiography in the contemporary diagnostic and prognostic approaches to HHD.

Integrative Assessment of Cardiopulmonary Fitness Using Cardiopulmonary Exercise Test With Supine Bicycle Echocardiography in Patients Presenting Dyspnea

BACKGROUND

Cardiopulmonary exercise test (CPET) with supine bicycle echocardiography (SBE) enables comprehensive physiologic assessment during exercise. We characterized cardiopulmonary fitness by integrating CPET-SBE parameters and evaluated its prognostic value in patients presenting with dyspnea.

METHODS AND RESULTS

We retrospectively reviewed 473 consecutive patients who underwent CPET-SBE for dyspnea evaluation. A dimensionality reduction process was applied, transforming 24 clinical and CPET-SBE parameters into a 2-dimensional feature map, followed by patient clustering based on the data distribution. Clinical and exercise features were compared among the clusters in addition to the 5-year risk of clinical outcome (a composite of cardiovascular death and heart failure hospitalization). Maximum exercise effort (R >1) was achieved in 95% of cases. Through dimensionality reduction, 3 patient clusters were derived: Group 1 (n=157), 2 (n=104), and 3 (n=212). Median age and female proportion increased from Group 1 to 2, and 3, although resting echocardiography parameters showed no significant abnormalities among the groups. There was a worsening trend in the exercise response from Group 1 to 2 and 3, including left ventricular diastolic function, oxygen consumption, and ventilatory efficiency. During follow-up (median 6.0 [1.6-10.4] years), clinical outcome increased from Group 1 to 2 and 3 (5-year rate 3.7% versus 7.0% versus 13.0%, respectively; log-rank P=0.02), with higher risk in Group 2 (hazard ratio, 1.94 [95% CI, 0.52-7.22]) and Group 3 (3.92 [1.34-11.42]) compared with Group 1.

CONCLUSIONS

Comprehensive evaluation using CPET-SBE can reveal distinct characteristics of cardiopulmonary fitness in patients presenting with dyspnea, potentially enhancing outcome prediction.

Cardiopulmonary Exercise Testing in Heart Failure With Preserved Ejection Fraction: Technique Principles, Current Evidence, and Future Perspectives

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial clinical syndrome involving a rather complex pathophysiologic substrate and quite a challenging diagnosis. Exercise intolerance is a major feature of HFpEF, and in many cases, diagnosis is suspected in subjects presenting with exertional dyspnea. Cardiopulmonary exercise testing (CPET) is a noninvasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, hematopoietic, neuropsychological, and metabolic functions during maximal or submaximal exercise. The assessment is based on the principle that system failure typically occurs when the system is under stress, and thus, CPET is currently considered to be the gold standard for identifying exercise intolerance, allowing the differential diagnosis of underlying causes. CPET is used in observational studies and clinical trials in HFpEF; however, in most cases, only a few from a wide variety of CPET parameters are examined, while the technique is largely underused in everyday cardiology practice. This article discusses the basic principles and methodology of CPET and studies that utilized CPET in patients with HFpEF, in an effort to increase awareness of CPET capabilities among practicing cardiologists.

Exercise Physiology and Cardiopulmonary Exercise Testing

Aerobic, or endurance, exercise is an energy requiring process supported primarily by energy from oxidative adenosine triphosphate synthesis. The consumption of oxygen and production of carbon dioxide in muscle cells are dynamically linked to oxygen uptake (V̇O2) and carbon dioxide output (V̇CO2) at the lung by integrated functions of cardiovascular, pulmonary, hematologic, and neurohumoral systems. Maximum oxygen uptake (V̇O2max) is the standard expression of aerobic capacity and a predictor of outcomes in diverse populations. While commonly limited in young fit individuals by the capacity to deliver oxygen to exercising muscle, (V̇O2max) may become limited by impairment within any of the multiple systems supporting cellular or atmospheric gas exchange. In the range of available power outputs, endurance exercise can be partitioned into different intensity domains representing distinct metabolic profiles and tolerances for sustained activity. Estimates of both V̇O2max and the lactate threshold, which marks the upper limit of moderate-intensity exercise, can be determined from measures of gas exchange from respired breath during whole-body exercise. Cardiopulmonary exercise testing (CPET) includes measurement of V̇O2 and V̇CO2 along with heart rate and other variables reflecting cardiac and pulmonary responses to exercise. Clinical CPET is conducted for persons with known medical conditions to quantify impairment, contribute to prognostic assessments, and help discriminate among proximal causes of symptoms or limitations for an individual. CPET is also conducted in persons without known disease as part of the diagnostic evaluation of unexplained symptoms. Although CPET quantifies a limited sample of the complex functions and interactions underlying exercise performance, both its specific and global findings are uniquely valuable. Some specific findings can aid in individualized diagnosis and treatment decisions. At the same time, CPET provides a holistic summary of an individual's exercise function, including effects not only of the primary diagnosis, but also of secondary and coexisting conditions.

Prognostic Role of Metabolic Exercise Testing in Heart Failure

Heart failure is a clinical syndrome with significant heterogeneity in presentation and severity. Serial risk-stratification and prognostication can guide management decisions, particularly in advanced heart failure, when progression toward advanced therapies or end-of-life care is warranted. Each currently utilized prognostic marker carries its own set of challenges in acquisition, reproducibility, accuracy, and significance. Left ventricular ejection fraction is foundational for heart failure syndrome classification after clinical diagnosis and remains the primary parameter for inclusion in most clinical trials; however, it does not consistently correlate with symptoms and functional capacity, which are also independently prognostic in this patient population. Utilizing the left ventricular ejection fraction as the sole basis of prognostication provides an incomplete characterization of this condition and is prone to misguide medical decision-making when used in isolation. In this review article, we survey and exposit the important role of metabolic exercise testing across the heart failure spectrum, as a complementary diagnostic and prognostic modality. Metabolic exercise testing, also known as cardiopulmonary exercise testing, provides a comprehensive evaluation of the multisystem (i.e., neurological, respiratory, circulatory, and musculoskeletal) response to exercise performance. These differential responses can help identify the predominant contributors to exercise intolerance and exercise symptoms. Additionally, the aerobic exercise capacity (i.e., oxygen consumption during exercise) is directly correlated with overall life expectancy and prognosis in many disease states. Specifically in heart failure patients, metabolic exercise testing provides an accurate, objective, and reproducible assessment of the overall circulatory sufficiency and circulatory reserve during physical stress, being able to isolate the concurrent chronotropic and stroke volume responses for a reliable depiction of the circulatory flow rate in real time.

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.

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.

Arterial Hypertension and Cardiopulmonary Function: The Value of a Combined Cardiopulmonary and Echocardiography Stress Test

Arterial hypertension (AH) is a global burden and the leading risk factor for mortality worldwide. Haemodynamic abnormalities, longstanding neurohormonal and inflammatory activation, which are commonly observed in patients with AH, promote cardiac structural remodeling ultimately leading to heart failure (HF) if blood pressure values remain uncontrolled. While several epidemiological studies have confirmed the strong link between AH and HF, the pathophysiological processes underlying this transition remain largely unclear. The combined cardiopulmonary-echocardiography stress test (CPET-ESE) represents a precious non-invasive aid to detect alterations in patients at the earliest stages of HF. The opportunity to study the response of the cardiovascular system to exercise, and to differentiate central from peripheral cardiovascular maladaptations, makes the CPET-ESE an ideal technique to gain insights into the mechanisms involved in the transition from AH to HF, by recognizing alterations that might be silent at rest but influence the response to exercise. Identifications of these subclinical alterations might allow for a better risk stratification in hypertensive patients, facilitating the recognition of those at higher risk of evolution towards established HF. This may also lead to the development of novel preventive strategies and help tailor medical treatment. The purpose of this review is to summarise the potential advantages of using CPET-ESE in the characterisation of hypertensive patients in the cardiovascular continuum.

Pathophysiological and diagnostic importance of fatty acid-binding protein 1 in heart failure with preserved ejection fraction

Elevated intracardiac pressure at rest and/or exercise is a fundamental abnormality in heart failure with preserved ejection fraction (HFpEF). Fatty acid-binding protein 1 (FABP1) is proposed to be a sensitive biomarker for liver injury. We sought to determine whether FABP1 at rest would be elevated in HFpEF and would correlate with echocardiographic markers of intracardiac pressures at rest and during exercise. In this prospective study, subjects with HFpEF (n = 22) and control subjects without HF (n = 23) underwent resting FABP1 measurements and supine bicycle exercise echocardiography. Although levels of conventional hepatic enzymes were similar between groups, FABP1 levels were elevated in HFpEF compared to controls (45 [25–68] vs. 18 [14–24] ng/mL, p = 0.0008). FABP1 levels were correlated with radiographic and blood-based markers of congestion, hemodynamic derangements during peak exercise (E/e’, r = 0.50; right atrial pressure, r = 0.35; pulmonary artery systolic pressure, r = 0.46), reduced exercise cardiac output (r = − 0.49), and poor exercise workload achieved (r = − 0.40, all p < 0.05). FABP1 distinguished HFpEF from controls with an area under the curve of 0.79 (p = 0.003) and had an incremental diagnostic value over the H₂FPEF score (p = 0.007). In conclusion, FABP1 could be a novel hepatic biomarker that associates with hemodynamic derangements, reduced cardiac output, and poor exercise capacity in HFpEF.

Cardiopulmonary Exercise Test in the Detection of Unexplained Post-COVID-19 Dyspnea

There is emerging evidence of prolonged recovery in survivors of coronavirus disease 2019 (COVID-19), even in those with mild COVID-19. In this paper, we report a case of a 39-year-old male with excessive body weight and a history of borderline values of arterial hypertension without therapy, who was mainly complaining of progressive dyspnea after being diagnosed with mild COVID-19. According to the recent guidelines on the holistic assessment and management of patients who had COVID-19, all preferred diagnostic procedures, including multidetector computed tomography (CT), CT pulmonary angiogram, and echocardiography, should be conducted. However, in our patient, no underlying cardiopulmonary disorder has been established. Therefore, considering all additional symptoms our patient had beyond dyspnea, our initial differential diagnosis included anxiety-related dysfunctional breathing. However, psychiatric evaluation revealed that our patient had only a mild anxiety level, which was unlikely to provoke somatic complaints. We decided to perform further investigations considering that cardiopulmonary exercise test (CPET) represents a reliable diagnostic tool for patients with unexplained dyspnea. Finally, the CPET elucidated the diastolic dysfunction of the left ventricle, which was the most probable cause of progressive dyspnea in our patient. We suggested that, based on uncontrolled cardiovascular risk factors our patient had, COVID-19 triggered a subclinical form of heart failure (HF) with preserved ejection fraction (HFpEF) to become clinically manifest. Recently, the new onset, exacerbation, or transition from subclinical to clinical HFpEF has been associated with COVID-19. Therefore, in addition to the present literature, our case should warn physicians on HFpEF among survivors of COVID-19.

Combined use of stress echocardiography and cardiopulmonary exercise testing to assess exercise intolerance in patients treated for acute myocardial infarction

Exercise intolerance after acute myocardial infarction (AMI) is a predictor of worse prognosis, but its causes are complex and poorly studied. This study assessed the determinants of exercise intolerance using combined stress echocardiography and cardiopulmonary exercise testing (CPET-SE) in patients treated for AMI. We prospectively enrolled patients with left ventricular ejection fraction (LV EF) ≥40% for more than 4 weeks after the first AMI. Stroke volume, heart rate, and arteriovenous oxygen difference (A-VO2Diff) were assessed during symptom-limited CPET-SE. Patients were divided into four groups according to the percentage of predicted oxygen uptake (VO2) (Group 1, <50%; Group 2, 50-74%; Group 3, 75-99%; and Group 4, ≥100%). Among 81 patients (70% male, mean age 58 ± 11 years, 47% ST-segment elevation AMI) mean peak VO2 was 19.5 ± 5.4 mL/kg/min. A better exercise capacity was related to a higher percent predicted heart rate (Group 2 vs. Group 4, p <0.01), higher peak A-VO2Diff (Group 1 vs. Group 3, p <0.01) but without differences in stroke volume. Peak VO2 and percent predicted VO2 had a significant positive correlation with percent predicted heart rate at peak exercise (r = 0.28, p = 0.01 and r = 0.46, p < 0.001) and peak A-VO2Diff (r = 0.68, p <0.001 and r = 0.36, p = 0.001) but not with peak stroke volume. Exercise capacity in patients treated for AMI with LV EF ≥40% is related to heart rate response during exercise and peak peripheral oxygen extraction. CPET-SE enables non-invasive assessment of the mechanisms of exercise intolerance.

The Future of Exercise-Based Cardiac Rehabilitation for Patients With Heart Failure

Cardiac rehabilitation (CR) is a comprehensive program that includes exercise training, titration of medical therapy, lifestyle modification, educational support, and psychosocial assessment. All these components are safe and beneficial resulting in significant improvements in quality of life, functional capacity, mortality, and hospital readmission. Current guidelines support its use in a broad spectrum of cardiac disease. This review focuses on exercise-based CR for heart failure (HF) patients in whom CR is a recommended treatment. Exercise should be prescribed according to a personalized approach, optimizing, and tailoring the rehabilitative program to the patient's characteristics. Specific CR programs are dedicated to older patients, those with HF and preserved ejection fraction, and recipients of cardiac implantable electronic devices or left ventricular assistance device. Telemedicine may increase CR participation and overcome some of the barriers that limit its utilization.

Hemodynamic Heterogeneity of Reduced Cardiac Reserve Unmasked by Volumetric Exercise Echocardiography

Background: Two-dimensional volumetric exercise stress echocardiography (ESE) provides an integrated view of left ventricular (LV) preload reserve through end-diastolic volume (EDV) and LV contractile reserve (LVCR) through end-systolic volume (ESV) changes. Purpose: To assess the dependence of cardiac reserve upon LVCR, EDV, and heart rate (HR) during ESE. Methods: We prospectively performed semi-supine bicycle or treadmill ESE in 1344 patients (age 59.8 ± 11.4 years; ejection fraction = 63 ± 8%) referred for known or suspected coronary artery disease. All patients had negative ESE by wall motion criteria. EDV and ESV were measured by biplane Simpson rule with 2-dimensional echocardiography. Cardiac index reserve was identified by peak-rest value. LVCR was the stress-rest ratio of force (systolic blood pressure by cuff sphygmomanometer/ESV, abnormal values ≤2.0). Preload reserve was defined by an increase in EDV. Cardiac index was calculated as stroke volume index * HR (by EKG). HR reserve (stress/rest ratio) <1.85 identified chronotropic incompetence. Results: Of the 1344 patients, 448 were in the lowest tertile of cardiac index reserve with stress. Of them, 303 (67.6%) achieved HR reserve <1.85; 252 (56.3%) had an abnormal LVCR and 341 (76.1%) a reduction of preload reserve, with 446 patients (99.6%) showing ≥1 abnormality. At binary logistic regression analysis, reduced preload reserve (odds ratio [OR]: 5.610; 95% confidence intervals [CI]: 4.025 to 7.821), chronotropic incompetence (OR: 3.923, 95% CI: 2.915 to 5.279), and abnormal LVCR (OR: 1.579; 95% CI: 1.105 to 2.259) were independently associated with lowest tertile of cardiac index reserve at peak stress. Conclusions: Heart rate assessment and volumetric echocardiography during ESE identify the heterogeneity of hemodynamic phenotypes of impaired chronotropic, preload or LVCR underlying a reduced cardiac reserve.

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.

Utilizing Machine Learning Techniques to Predict the Efficacy of Aerobic Exercise Intervention on Young Hypertensive Patients Based on Cardiopulmonary Exercise Testing

Recently, the incidence of hypertension has significantly increased among young adults. While aerobic exercise intervention (AEI) has long been recognized as an effective treatment, individual differences in response to AEI can seriously influence clinicians' decisions. In particular, only a few studies have been conducted to predict the efficacy of AEI on lowering blood pressure (BP) in young hypertensive patients. As such, this paper aims to explore the implications of various cardiopulmonary metabolic indicators in the field by mining patients' cardiopulmonary exercise testing (CPET) data before making treatment plans. CPET data are collected "breath by breath" by using an oxygenation analyzer attached to a mask and then divided into four phases: resting, warm-up, exercise, and recovery. To mitigate the effects of redundant information and noise in the CPET data, a sparse representation classifier based on analytic dictionary learning was designed to accurately predict the individual responsiveness to AEI. Importantly, the experimental results showed that the model presented herein performed better than the baseline method based on BP change and traditional machine learning models. Furthermore, the data from the exercise phase were found to produce the best predictions compared with the data from other phases. This study paves the way towards the customization of personalized aerobic exercise programs for young hypertensive patients.

The Role of Stress Echocardiography in the Early Detection of Diastolic Dysfunction in Non-Severe Chronic Obstructive Pulmonary Disease Patients

Fundamento

A dispneia por esforço é uma queixa comum de pacientes com insuficiência cardíaca com fração de ejeção preservada (ICFEP) e doença pulmonar obstrutiva crônica (DPOC). A ICFEP é comum na DPOC e é um fator de risco independente para a progressão e exacerbação da doença. A detecção precoce, portanto, tem grande relevância clínica.

Objetivos

O objetivo deste estudo foi detectar a frequência de ICFEP mascarada em pacientes com DPOC não grave com dispneia aos esforços, sem doença cardiovascular manifesta, e analisar a correlação entre ICFEP mascarada e os parâmetros do teste cardiopulmonar de exercício (TCPE).

Métodos

Aplicamos o TCPE em 104 pacientes com DPOC não grave com dispneia aos esforços, sem doença cardiovascular evidente. A ecocardiografia foi realizada antes e no pico do TCPE. Os valores de corte para disfunção diastólica ventricular esquerda e direita induzida por estresse (DDVE/DDVD) foram E/e’ >15; E/e’ >6, respectivamente. A análise de correlação foi feita entre os parâmetros do TCPE e o estresse E/d’. Valor de p<0,05 foi considerado significativo.

Resultados

64% dos pacientes tinham DDVE induzida por estresse; 78% tinham DDVD induzida por estresse. Ambos os grupos com estresse DDVE e DDVD obtiveram carga menor, V’O₂ e pulso de O₂ mais baixos, além de apresentarem redução na eficiência ventilatória (maiores inclinações de VE/VCO₂). Nenhum dos parâmetros do TCPE foram correlacionados com E/e’ DDVE/DDVD induzida por estresse.

Conclusão

Há uma alta prevalência de disfunção diastólica induzida por estresse em pacientes com DPOC não grave com dispneia aos esforços, sem doença cardiovascular evidente. Nenhum dos parâmetros do TCPE se correlaciona com E/e’ induzida por estresse. Isso demanda a realização de Ecocardiografia sob estresse por exercício (EES) e TCPE para detecção precoce e manejo adequado da ICFEP mascarada nesta população. (Arq Bras Cardiol. 2021; 116(2):259-265)

Left ventricular diastolic dysfunction in non-severe chronic obstructive pulmonary disease - a step forward in cardiovascular comorbidome

Chronic obstructive pulmonary disease (COPD) augments the likelihood of having left ventricular diastolic dysfunction (LVDD)–precursor of heart failure with preserved ejection fraction (HFpEF). LVDD shares overlapping symptomatology (cough and dyspnea) with COPD. Stress induced LVDD is indicative of masked HFpEF. Our aim was to evaluate the predictive value of inflammatory, oxidative stress, cardio-pulmonary and echocardiographic parameters at rest for the diagnosis of stress LVDD in non-severe COPD patients, who complain of exertional dyspnea and are free of overt cardiovascular diseases. A total of 104 COPD patients (26 patients with mild and 78 with moderate COPD) underwent echocardiography before cardio-pulmonary exercise testing (CPET) and 1–2 minutes after peak exercise. Patients were divided into two groups based on peak average E/e’: patients with stress induced left ventricular diastolic dysfunction (LVDD)—E/e’ > 15 masked HFpEF and patients without LVDD—without masked HFpEF. CPET and echocardiographic parameters at rest were measured and their predictive value for stress E/e’ was analysed. Markers for inflammation (resistin, prostaglandine E2) and oxidative stress (8-isoprostanes) were also determined. Stress induced LVDD occurred in 67/104 patients (64%). Those patients showed higher VE/VCO2 slope. None of the CPET parameters was an independent predictor for stress LVDD.Except for prostglandine E2, none of the inflammatory or oxidative stress markers correlated to stress E/e’. The best independent predictors for stress LVDD (masked HFpEF) were RAVI, right ventricular parasternal diameter and RV E/A >0.75. Their combination predicted stress LVDD with the accuracy of 91.2%. There is a high prevalence of masked HFpEF in non-severe COPD with exertional dyspnea, free of overt cardiovascular disease. RAVI, right ventricular parasternal diameter and RV E/A >0.75 were the only independent clinical predictors of masked HFpEF. 288.

Machine learning: at the heart of failure diagnosis

PURPOSE OF REVIEW

Refinement in machine learning (ML) techniques and approaches has rapidly expanded artificial intelligence applications for the diagnosis and classification of heart failure (HF). This review is designed to provide the clinician with the basics of ML, as well as this technologies future utility in HF diagnosis and the potential impact on patient outcomes.

RECENT FINDINGS

Recent studies applying ML methods to unique data sets available from electrocardiography, vectorcardiography, echocardiography, and electronic health records show significant promise for improving diagnosis, enhancing detection, and advancing treatment of HF. Innovations in both supervised and unsupervised methods have heightened the diagnostic accuracy of models developed to identify the presence of HF and further augmentation of model capabilities are likely utilizing ensembles of ML algorithms derived from different techniques.

SUMMARY

This article is an overview of recent applications of ML to achieve improved diagnosis of HF and the resultant implications for patient management.

Research based on the core pathogenesis in the treatment according to traditional Chinese medicine syndrome differentiation for heart failure with normal ejection fraction

BACKGROUND

The incidence of heart failure with normal ejection fraction (HFNEF) is increasing yearly, accounting for approximately half of all heart failure cases. Even after standardized treatment, the patient's prognosis is not good. Therefore, it is necessary to explore new treatment methods for HFNEF. Yangyin Shuxin Decoction, a traditional Chinese medicine prescription from our clinical experience in the treatment of HFNEF, has a potential cardioprotective effect. Preliminary clinical trials have shown that this prescription can improve the quality of life of HFNEF. This prompted us to use more objective indicators to further evaluate whether Yangyin Shuxin Decoction can improve the exercise capacity in HENEF patients.

METHODS

This is a single-center parallel randomized controlled trial. The 64 patients who met the inclusion criteria were from the Cardiovascular Clinic. They will be randomly assigned to the treatment group (Yangying Shuxin Decoction combined with standard treatment) or the control group (standard treatment) according to the ratio of 1:1. The course of treatment will be 2 weeks. Both groups were interviewed at the following time points: of at enrollment (V1), and week 2 (V2), week 4 (V3), week 8 (V4), and week 12 (V5) after enrollment. The primary indicator is the peak oxygen consumption (Peak VO2) of the cardiopulmonary exercise test (CPET). Secondary indicators include CPET indicators such as anaerobic threshold oxygen consumption, carbon dioxide ventilation equivalent slope, echocardiographic indicators such as the ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity(E/e'), left atrial volume index (LAVI), left ventricular mass index (LVMI), the peak velocity of tricuspid regurgitation (TR), B-type natriuretic peptide (BNP), New York Heart Association (NYHA) cardiac function grading, and so on. These indicators will be used to evaluate the effect of Yangyin Shuxin Decoction on exercise capacity in patients with HFNEF.

DISCUSSION

At present, it is unclear whether the exercise capacity can be maintained after long-term use of Yangyin Shuxin Decoction. In this study, we will evaluate whether Yangyin Shuxin Decoction can improve the exercise capacity and quality of life of patients with HFNEF. This will provide an objective basis for the therapeutic effect of traditional Chinese medicine on HFNEF.

TRIAL REGISTRATION

This study protocol has been listed in the Chinese Clinical Trial Registry (registration number: ChiCTR-IOR-17014206, http://www.chictr.org.cn/showproj.aspx?proj=24304) on December 28, 2017.

Prognostic significance of exercise-induced diastolic dysfunction: A systematic review

BACKGROUND

Recent guidelines recommend diastolic stress testing among patients with unexplained dyspnea. Previous studies have reported exercise related change in diastolic parameters as a prognostic marker for worse outcomes. However, the role of exercise-induced diastolic dysfunction (DD) in predicting adverse outcomes has not been fully established.

METHOD

We conducted a meta-analysis to explore the prognostic significance of exercise-induced DD. PUBMED/EMBASE/SCOPUS databases were searched for studies reporting adverse outcomes in patients undergoing exercise echocardiography based on diastolic response during exercise. Exercise-induced DD was defined as an increase in E/e' or E/A ratio with stress. Outcomes of interest were cardiovascular mortality or hospitalizations.

RESULTS

A total of 8 studies were identified, including 4,462 patients who underwent exercise stress echocardiography. The follow-up ranged from 13 months to 5 years. The major indication for stress testing was exertional dyspnea. All studies reported cardiac mortality and hospitalization in the composite outcome. Meta-analysis conducted using random-effects model showed that exercise-induced DD was associated with a higher likelihood of cardiovascular mortality or hospitalization (HR = 1.32, P < .05). Significant heterogeneity was noted among the studies.

CONCLUSIONS

Exercise-induced DD is associated with worse cardiovascular outcomes. Changes in echocardiographic parameters such as e' with exercise might be useful for risk stratification and identification of high-risk patients.

The link between dynamic hyperinflation, autonomic dysfunction and exercise testing parameters with masked heart failure in patients with non-severe obstructive pulmonary disease

OBJECTIVES

Autonomic dysfunction (AD) and dynamic hyperinflation (DH) have been implicated as pathophysiological mechanisms of heart failure with preserved ejection fraction (HFpEF) in chronic obstructive pulmonary disease (COPD) patients. Their association, however, remains elusive: The aims of the study were: (1) to determine the prevalence of AD and DH in non-severe COPD patients, with exertional dyspnea, without clinically overt cardio-vascular (CV) comorbidities; (2) to analyze the correlation and clinical significance between DH, AD, and maksed HFpEF.

METHODS

We applied CPET in 68 subjects. Echocardiography was performed before CPET and 1-2 min after peak exercise. IC manoeuvres were applied. Patients were divided into two groups: patients with and without masked HFpEF. Wilkoff method calculated the meatabolic - chronotropic relationship (MCR). Chronotropic incompetence (CI) and abnormal HR recovery (HRR) were determined.

RESULTS

The prevalence of CI was 77 vs. 52% in patients with/without masked HFpEF; of abnormal HRR - 98 vs. 62% respectively; of DH - 53 vs. 29%. ICdyn was associated with AD. Univariate regression showed association between masked HFpEF, ICdyn, HRR, oxygenuptake ('VO₂), 'VO₂ at anaerobic threshold, oxygen (O₂) pulse and 'VE/'VCO₂ slope. None of these parameters is an independent predictor for masked HFpEF.

CONCLUSIONS

DH, AD, and masked HFpEF are prevalent in non-severe COPD patients, who complain of exertional dyspnea and are free of clinically overt CV comorbidities. DH is independently associated with AD. Neither AD, nor DH and CPET are independent predictors for masked HFpEF.

Diagnostic algorithm for HFpEF: how much is the recent consensus applicable in clinical practice?

Heart failure with preserved ejection fraction (HFpEF) represents an important cardiovascular entity with increasing prevalence and relatively high mortality. The agreement about diagnostic algorithm for HFpEF is still missing. Echocardiographic approach remains the cornerstone in HFpEF diagnosis. Echocardiographic diastolic stress test provides numerous useful parameters that correlated well with indexes obtained by cardiac catheterization. Recently published consensus recommended new scoring system that included functional and structural echocardiographic parameters, as well as biomarkers. The new score for evaluation of HFpEF introduces a new set of parameters and proposed novel cutoff values for some of them. There are several important points that need to be resolved before full acceptance and clinical usage. First, some cutoff values are new and represent the result of expert consensus, without previous validation. Second, many patients with hypertension, obesity, and diabetes would be referred for further investigations as the result of this scoring, which is difficult to achieve in clinical circumstances. Third, the consensus equalized non-invasive and invasive diastolic stress tests in diagnosing of HFpEF, which is not a small issue. Namely, even though cardiac catheterization provides the final confirmation of elevated left ventricular filling pressures, it is still an invasive method, associated with procedural risk and other limitations. The aim of this review was to summarize the current knowledge diagnosis of HFpEF, as well as the recent consensus about diagnostic algorithm in patients with suspected HFpEF with its advantages and disadvantages.

Autonomic dysfunction, cardio-pulmonary exercise testing and masked heart failure with preserved ejection fraction in non-severe chronic obstructive pulmonary disease

BACKGROUND

Autonomic dysfunction (AD) and cardiopulmonary exercise testing (CPET) parameters have been associated with masked heart failure with preserved ejection fraction (HFpEF) in the general population. Their clinical significance for masked HFpEF in chronic obstructive pulmonary disease (COPD) is however elusive.

AIM

The aim of the study was to determine the prevalence, correlation and clinical significance of AD and CPET with masked HFpEF, in non-severe COPD patients, complaining of exertional dyspnoea, without clinically overt cardio-vascular (CV) comorbidities.

METHODS AND RESULTS

We applied CPET and echocardiography in 68 COPD subjects. Echocardiography was performed before CPET and 1-2 min after peak exercise. Patients were divided into two groups: patients with and without masked HFpEF. Peak E/e' - 15 was applied as a cut-off. Chronotropic incompetence (CI) was assumed if both failure to reach the target heart rate (HR) on exercise and diminished heart rate reserve <80% occurred. Abnormal HR recovery (HRR) was taken if the decline is <12 beats within the first minute after exercise cessation. Univariate regression showed association between masked HFpEF, HRR, VO2, VO2 at AT, oxygen pulse and VE/VCO2 slope. The multivariate regression demonstrated HRR as the only independent predictor of masked HFpEF - (OR 10.28; 95% CI (3.55-29.80)).

CONCLUSION

Abnormal HRR is the only independent predictor of masked HFpEF in non-severe COPD patients. Despite of being associated with masked HFpEF, the lower VO2, lower oxygen pulse, higher VE/VCO2 slope and lower exercise load seem to be the consequences, rather than the triggers for it.

Haemodynamic and metabolic phenotyping of hypertensive patients with and without heart failure by combining cardiopulmonary and echocardiographic stress test

AIM

We combined cardiopulmonary exercise test (CPET) and exercise stress echocardiography (ESE) to identify early haemodynamic and metabolic alterations in patients with hypertension (HT) with and without heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Fifty stable HFpEF-HT outpatients (mean age 68 ± 14 years) on optimal medical therapy, 63 well-controlled HT subjects (mean age 63 ± 11 years) and 32 age and sex-matched healthy controls (mean age 59 ± 15 years) underwent a symptom-limited graded ramp bicycle CPET-ESE. The acquisition protocol included left ventricular cardiac output, global longitudinal strain, E/e', peak oxygen consumption (VO₂ ), non-invasive arterial-venous oxygen content difference (AVO₂ diff) and lung ultrasound B-lines. There was a decline in peak VO₂ from controls (24.4 ± 3 mL/min/kg) to HFpEF-HT (15.2 ± 2 mL/min/kg), passing through HT (18.7 ± 2 mL/min/kg; P < 0.0001). HFpEF-HT displayed a lower peak cardiac output (9.8 ± 0.9 L/min) compared to HT (12.6 ± 1.0 L/min; P = 0.02) and controls (13.3 ± 1.0 L/min; P = 0.01). Peak AVO₂ diff was reduced in HFpEF-HT and HT (13.3 ± 2 and 13.5 ± 2 mL/dL vs. controls: 16.9 ± 2 mL/dL; P < 0.0001). A different left ventricular contractility was observed among groups, expressed as low-load global longitudinal strain (-16.8 ± 5% in HFpEF-HT, -18.2 ± 3% in HT, and 20.9 ± 3% in controls; P < 0.0001), and distribution of E/e' and B-lines [HFpEF-HT: 13.7 ± 3 and 16, interquartile range (IQR) 10-22; HT: 9.5 ± 2 and 8, IQR 4-10; controls: 6.2 ± 2 and 0, IQR 0-2; P < 0.0001].

CONCLUSIONS

Reduced peak VO₂ values in HT with and without HFpEF may be the result of decreased AVO₂ diff. CPET-ESE can also identify mild signs of left ventricular systo-diastolic dysfunction and pulmonary congestion, promoting advances in personalized therapy.

Cardiopulmonary exercise testing and echocardiographic exam: an useful interaction

Cardiopulmonary exercise test (CPET) is a functional assessment that helps to detect disorders affecting the system involved in oxygen transport and utilization through the analysis of the gas exchange during exercise. The clinical application of CPET is various, it including training prescription, evaluation of treatment efficacy and outcome prediction in a broad spectrum of conditions. Furthermore, in patients with shortness of breath it provides pivotal information to bring out an accurate differential diagnosis between physical deconditioning, cardiopulmonary disease and muscular diseases. Modern software allows the breath-by-breath analysis of the volume of oxygen intake (VO₂), volume of carbon dioxide output (VCO₂) and expired air (VE). Through this analysis, CPET provides a series of additional parameters (peak VO₂, ventilatory threshold, VE/VCO₂ slope, end-tidal carbon dioxide exhaled) that characterize different patterns, helping in diagnosis process. Limitations to the routine use of CPET are mainly represented from the lack of measurement standardization and limited data from randomized multicentric studies. The integration of CPET with exercise stress echocardiography has been recently introduced in the clinical practice by integrating the diagnostic power offered by both the tools. This combined approach has been demonstrated to be valuable for diagnosing several cardiac diseases, including heart failure with preserved or reduced ejection fraction, cardiomyopathies, pulmonary arterial hypertension, valvular heart disease and coronary artery disease. Future investigations are needed to further promote this intriguing combination in the clinical and research setting.

Subclinical cardiac stiffness is associated with arterial stiffness in healthy young nulligravid women: Potential links to preeclampsia

OBJECTIVES

Preeclampsia is an independent risk factor for subsequent cardiovascular disease and diastolic dysfunction and has been linked to arterial stiffness. We hypothesized that arterial stiffness would be associated with echocardiographic markers of diastolic dysfunction in healthy nulligravid women.

STUDY DESIGN

31 healthy nulligravid women underwent assessment of peripheral arterial stiffness via aorto-femoral pulse wave velocity, popliteal distensibility and β stiffness measures as well as hemodynamic response to volume challenge. 22 underwent cardiac assessment via conventional and stress echocardiography with a focus on diastolic function utilizing tissue/pulse wave Doppler imaging and 3D speckle tracking. Bivariate associations between variables were evaluated using correlation coefficients (Pearson r) and Student's t-tests.

RESULTS

No participants had echocardiographic values meeting criteria for overt diastolic dysfunction. Baseline global circumferential strain was significantly correlated with distensibility and β stiffness (n = 18, r = -0.61, p = 0.007, n = 18, r = 0.56, p = 0.01). Peak deceleration time was correlated with βstiffness (n = 9; r = 0.80, p = 0.01). Pulse wave velocity was not significantly correlated with cardiac measures (p > 0.05). Family history of a first or second degree relative with myocardial infarction or hypertension was associated with decreased popliteal artery distensibility (p = 0.02 and p = 0.03, respectively).

CONCLUSIONS

In healthy nulligravid women there is evidence that markers of decreased left ventricular relaxation are associated with increased peripheral vascular stiffness as is a family history of myocardial infarction or hypertension. These findings raise the possibility that the diastolic dysfunction and arterial stiffness observed in the setting of preeclampsia are driven by underlying properties present prior to pregnancy and contribute to lifetime cardiovascular risk.

Saudi Heart Association (SHA) guidelines for the management of heart failure

Heart failure (HF) is the leading cause of morbidity and mortality worldwide and negatively impacts quality of life, healthcare costs, and longevity. Although data on HF in the Arab population are scarce, recently developed regional registries are a step forward to evaluating the quality of current patient care and providing an overview of the clinical picture. Despite the burden of HF in Saudi Arabia, there are currently no standardized protocols or guidelines for the management of patients with acute or chronic heart failure. Therefore, the Heart Failure Expert Committee, comprising 13 local specialists representing both public and private sectors, has developed guidelines to address the needs and challenges for the diagnosis and treatment of HF in Saudi Arabia. The ultimate aim of these guidelines is to assist healthcare professionals in delivering optimal care and standardized clinical practice across Saudi Arabia.

The Amount of Weight Loss Six Months after Bariatric Surgery: It Makes a Difference

BACKGROUND

Bariatric surgery, especially Roux-en-Y gastric bypass (RYGB), has become the most frequently used therapy for morbid obesity.

OBJECTIVES

The aim of this study was to examine the effects of surgically induced weight loss on cardiopulmonary function 6 months after the procedure, as well as the effect of such an intervention on well-known risk factors for cardiovascular diseases.

METHODS

This is a cross-sectional study on 66 morbidly obese patients (BMI ≥40 or ≥35 kg/m2 with present comorbidities), comparing their cardiopulmonary function prior to and 6 months after RYGB surgery.

RESULTS

The substantial amount of weight loss (29.80 ± 13.27 kg) after RYGB surgery was associated with significant reduction of comorbidities, especially diabetes and sedentary lifestyle (p = 0.005 and p = 0.002, respectively). Regarding functional capacity, there was significant increase in peak oxygen uptake (VO2 peak, p = 0.003), duration of exercise testing, metabolic equivalents (exercise time and METs, p < 0.001), and in peak O2 pulse. These findings were particularly pronounced in a group of patients who had lost more than 18% of initial weight.

CONCLUSIONS

Reduction of body weight after RYGB surgery is associated with significantly improved cardiorespiratory function 6 months after surgery, especially in patients who lost more than 18% of their initial body weight. In addition, substantial decreases in body weight were also associated with a reduction of cardiovascular risk factors such as diabetes, smoking, hypertriglyceridemia, and sedentary lifestyle.

Diastolic stress test echocardiography in patients with suspected heart failure with preserved ejection fraction: a pilot study

AIMS

The purpose of this pilot study was to assess the potential usefulness of diastolic stress test (DST) echocardiography in patients with suspected heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Patients with suspected HFpEF (left ventricular ejection fraction ≥ 50%, exertional dyspnoea, septal E/e' at rest 9-14, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) at rest < 220 pg/mL; n = 13) and a control group constituted from asymptomatic patients with arterial hypertension (n = 19) and healthy subjects (n = 18) were included. All patients were analysed by two-dimensional and Doppler echocardiography at rest and during exercise (DST) and underwent cardiopulmonary exercise testing and NT-proBNP analysis during exercise. HFpEF during exercise was defined as exertional dyspnoea and peak VO₂  ≤ 20.0 mL/min/kg. In patients with suspected HFpEF at rest, 84.6% of these patients developed HFpEF during exercise, whereas in the group of asymptomatic patients with hypertension and healthy subjects, the rate of developed HFpEF during exercise was 0%. Regarding the diagnostic performance of DST to detect HFpEF during exercise, an E/e' ratio >15 during exercise was the most accurate parameter to detect HFpEF (accuracy 86%), albeit a low sensitivity (45.5%). Nonetheless, combining E/e' with tricuspid regurgitation (TR) velocity > 2.8 m/s during exercise provided a significant increase in the sensitivity to detect patients with HFpEF during exercise (sensitivity 72.7%, specificity 79.5%, and accuracy 78%). Consistent with these findings, an increase of E/e' was significantly linked to worse peak VO₂ , and the combination of an increase of both E/e' and TR velocity was associated with elevated NT-proBNP values during exercise.

CONCLUSIONS

The findings of this pilot study suggest that DST using E/e' ratio and TR velocity could be of potential usefulness to diagnose HFpEF during exercise in patients with suspected HFpEF at rest.

Current Management and Future Directions of Heart Failure With Preserved Ejection Fraction: a Contemporary Review

Heart failure with preserved ejection fraction (HFpEF), a complex and debilitating syndrome, is commonly seen in elderly populations. Exacerbation of HFpEF is among the most common reasons for hospital admission in the USA. The high rate of morbidity and mortality from this condition underscores the fact that HFpEF is heterogeneous, complex, and poorly characterized. Randomized, controlled trials have been very successful at identifying treatments for HF with reduced ejection fraction (HFrEF), but effective treatment options for HFpEF are lacking. Here, we discuss (1) the pathophysiology of HFpEF, (2) a standardized diagnostic and therapeutic approach, (3) a comparison of the management of recent guidelines, and (4) challenges and future directions for HFpEF management. The authors believe that it is important to identify new subtypes of HFpEF to better classify genotypes and phenotypes of HFpEF and to develop novel targeted therapies. It is our hypothesis that big data analytics will shine new light on unique HFpEF phenotypes that better respond to treatment modalities.

Comparisons of Noninvasive Methods Used to Assess Exercise Stroke Volume in Heart Failure with Preserved Ejection Fraction

INTRODUCTION

Cardiopulmonary exercise testing (CPET) plays an important role in properly phenotyping signs and symptoms of heart failure with preserved ejection fraction (HFpEF). The prognostic value of CPET is strengthened when accompanied by cardiac hemodynamic measurements. Although recognized as the "gold" standard, cardiac catheterization is impractical for routine CPET. Thus, advancing the scientific/methodologic understanding of noninvasive techniques for exercise cardiac hemodynamic assessment is clinically impactful in HFpEF. This study tested the concurrent validity of noninvasive acetylene gas (C2H2) uptake, echocardiography (ECHO), and oxygen pulse (O2pulse) for measuring/predicting exercise stroke volume (SV) in HFpEF.

METHODS

Eighteen white HFpEF and 18 age-/sex-matched healthy controls participated in upright CPET (ages, 69 ± 9 yr vs 63 ± 9 yr). At rest, 20 W, and peak exercise, SV was measured at steady-state via C2H2 rebreathe (SVACET) and ECHO (SVECHO), whereas O2pulse was derived (=V˙O2/HR).

RESULTS

Resting relationships between SVACET and SVECHO, SVECHO and O2pulse, or SVACET and O2pulse were significant in HFpEF (R = 0.30, 0.36, 0.67), but not controls (R = 0.07, 0.01, 0.09), respectively. Resting relationships persisted to 20 W in HFpEF (R = 0.70, 0.53, 0.70) and controls (R = 0.05, 0.07, 0.21), respectively. Peak exercise relationships were significant in HFpEF (R = 0.62, 0.24, 0.64), but only for SVACET versus O2pulse in controls (R = 0.07, 0.04, 0.33), respectively. Standardized standard error of estimate between techniques was strongest in HFpEF at 20 W: SVACET versus SVECHO = 0.57 ± 0.22; SVECHO versus O2pulse = 0.71 ± 0.28; SVACET versus O2pulse = 0.56 ± 0.22.

CONCLUSIONS

Constituting a clinically impactful step towards construct validation testing, these data suggest SVACET, SVECHO, and O2pulse demonstrate moderate-to-strong concurrent validity for measuring/predicting exercise SV in HFpEF.

Rest and exercise hemodynamic and metabolic findings in active duty soldiers referred for cardiac catheterization to exclude heart disease: Insights from past invasive cardiopulmonary exercise testing using multisensor high fidelity catheters

OBJECTIVE

This study describes results of iCPET from the past, which used submaximal stress and multisensor high-fidelity catheters to exclude heart disease in a unique population of young adults.

BACKGROUND

There has been resurgence in comprehensive hemodynamic evaluation of complex cardiovascular patients. Although dynamic assessments during cardiac catheterization have become commonplace, there remains limited information regarding left and right heart hemodynamic changes during supine exercise in young adults.

METHODS

The study population was derived from a retrospective review of catheterization records at Brooke Army Medical Center for active duty patients (ages: 19-40 years) in whom hemodynamic waveforms were obtained with multisensor high-fidelity catheters and supine exercise testing (53.1 ± 12.6 watts) and angiography performed to exclude heart disease. We report findings from 41 males and 1 female (ages: 19-40 years) found free of heart disease.

RESULTS

Submaximal exercise was associated with ≈ fourfold (P < 0.001) increase in minute ventilation (VE), O₂ consumption (VO₂ ) and carbon dioxide production (VCO₂ ). VE/VCO₂ ratio decreased (-16.8 ± 13.9%, P < 0.001) and VE/VCO₂ slope was 22.6 ± 0.6 (±SE). Cardiac index (CI) increased with VO₂ (ΔCI/ΔVO₂ slope = 7.6 ± 2.2). Heart rate increased nearly 10 bpm per 100 mL O₂ /min/M² , whereas, changes in stroke volume were more variable. Pulmonary artery (PA) saturations fell from 77 to 55% (P < 0.001). No change was noted in mean right atrial pressures; PA pressures increased ≈10 mm Hg (P < 0.001). Pulmonary capillary wedge and left ventricular end-diastolic pressures increased ≈2 mm Hg (P < 0.001) but variability noted between individuals.

CONCLUSION

This study provides insight into past practices of invasive cardiopulmonary testing and furthers the understanding of metabolic and hemodynamic changes in a young population during supine submaximal exercise. © 2017 Wiley Periodicals, Inc.

Shortness of breath in clinical practice: A case for left atrial function and exercise stress testing for a comprehensive diastolic heart failure workup

The symptom cluster of shortness of breath (SOB) contributes significantly to the outpatient workload of cardiology services. The workup of these patients includes blood chemistry and biomarkers, imaging and functional testing of the heart and lungs. A diagnosis of diastolic heart failure is inferred through the exclusion of systolic abnormalities, a normal pulmonary function test and normal hemoglobin, coupled with diastolic abnormalities on echocardiography. Differentiating confounders such as obesity or deconditioning in a patient with diastolic abnormalities is difficult. While the most recent guidelines provide more avenues for diagnosis, such as incorporating the left atrial size, little emphasis is given to understanding left atrial function, which contributes to at least 25% of diastolic left ventricular filling; additionally, exercise stress testing to elicit symptoms and test the dynamics of diastolic parameters, especially when access to the "gold standard" invasive tests is lacking, presents clinical translational gaps. It is thus important in diastolic heart failure work up to understand left atrial mechanics and the role of exercise testing to build a comprehensive argument for the diagnosis of diastolic heart failure in a patient presenting with SOB.

Exercise testing in heart failure: a contemporary discussion in an era of novel diagnostic techniques and biomarkers

PURPOSE OF REVIEW

The purpose of this review is to highlight recent advances in the field of exercise testing for patients with heart failure.

RECENT FINDINGS

The importance of assessment of cardiorespiratory fitness (CRF) and exercise testing in heart failure is highlighted in the consensus recommendation of the American Heart Association. Contemporary studies have validated the independent and incremental strength of CRF metrics in patients with heart failure and coronary artery disease. The use of respiratory gas analysis and imaging or hemodynamics during physical exercise is feasible and results in high prognostic utility across the continuum of heart failure. Understanding how CRF metrics complement existing and novel biomarkers and risk scores is an emerging subject of scientific inquiry.

SUMMARY

In the current era of personalized medicine, integrating CRF, imaging and circulating biomarkers will allow us to further develop individualized strategies for improving outcome in patients with heart failure.

Prognostic Value of Cardiopulmonary Exercise Testing in Heart Failure With Reduced, Midrange, and Preserved Ejection Fraction

Background

This study aimed to compare the independent and incremental prognostic value of peak oxygen consumption (VO₂) and minute ventilation/carbon dioxide production (VE/VCO₂) in heart failure (HF) with preserved (HFpEF), midrange (HFmEF), and reduced (HFrEF) ejection fraction (LVEF).

Methods and Results

In 195 HFpEF (LVEF ≥50%), 144 HFmEF (LVEF 40–49%), and 630 HFrEF (LVEF <40%) patients, we assessed the association of cardiopulmonary exercise testing variables with the composite outcome of death, left ventricular assist device implantation, or heart transplantation (256 events; median follow‐up of 4.2 years), and 2‐year incident HF hospitalization (244 events). In multivariable Cox regression analysis, greater association with outcomes in HFpEF than HFrEF were noted with peak VO₂ (HR [95% confidence interval]: 0.76 [0.67–0.87] versus 0.87 [0.83–0.90] for the composite outcome, P_interaction=0.052; 0.77 [0.69–0.86] versus 0.92 [0.88–0.95], respectively for HF hospitalization, P_interaction=0.003) and VE/VCO₂ slope (1.11 [1.06–1.17] versus 1.04 [1.03–1.06], respectively for the composite outcome, P_interaction=0.012; 1.10 [1.05–1.15] versus 1.04 [1.03–1.06], respectively for HF hospitalization, P_interaction=0.019). In HFmEF, peak VO₂ and VE/VCO₂ slope were associated with the composite outcome (0.79 [0.70–0.90] and 1.12 [1.05–1.19], respectively), while only peak VO₂ was related to HF hospitalization (0.81 [0.72–0.92]). In HFpEF and HFrEF, peak VO₂ and VE/VCO₂ slope provided incremental prognostic value beyond clinical variables based on the C‐statistic, net reclassification improvement, and integrated diagnostic improvement, with models containing both measures demonstrating the greatest incremental value.

Conclusions

Both peak VO₂ and VE/VCO₂ slope provided incremental value beyond clinical characteristics and LVEF for predicting outcomes in HFpEF. Cardiopulmonary exercise testing variables provided greater risk discrimination in HFpEF than HFrEF.

Physiological dead space and arterial carbon dioxide contributions to exercise ventilatory inefficiency in patients with reduced or preserved ejection fraction heart failure

AIMS

Patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction demonstrate an increased ventilatory equivalent for carbon dioxide (V̇_E /V̇CO₂ ) slope. The physiological correlates of the V̇_E /V̇CO₂ slope remain unclear in the two HF phenotypes. We hypothesized that changes in the physiological dead space to tidal volume ratio (V_D /V_T ) and arterial CO₂ tension (PaCO₂ ) differentially contribute to the V̇_E /V̇CO₂ slope in HFrEF vs. HFpEF.

METHODS AND RESULTS

Adults with HFrEF (n = 32) and HFpEF (n = 27) [mean ± standard deviation (SD) left ventricular ejection fraction: 22 ± 7% and 61 ± 9%, respectively; mean ± SD body mass index: 28 ± 4 kg/m² and 33 ± 6 kg/m² , respectively; P < 0.01] performed cardiopulmonary exercise testing with breath-by-breath ventilation and gas exchange measurements. PaCO₂ was measured via radial arterial catheterization. We calculated the V̇_E /V̇CO₂ slope via linear regression, and V_D /V_T  = 1 - [(863 × V̇CO₂ )/(V̇_E  × PaCO₂ )]. Resting V_D /V_T (0.48 ± 0.08 vs. 0.41 ± 0.11; P = 0.04), but not PaCO₂ (38 ± 5 mmHg vs. 40 ± 3 mmHg; P = 0.21) differed between HFrEF and HFpEF. Peak exercise V_D /V_T (0.39 ± 0.08 vs. 0.32 ± 0.12; P = 0.02) and PaCO₂ (33 ± 6 mmHg vs. 38 ± 4 mmHg; P < 0.01) differed between HFrEF and HFpEF. The V̇_E /V̇CO₂ slope was higher in HFrEF compared with HFpEF (44 ± 11 vs. 35 ± 8; P < 0.01). Variance associated with the V̇_E /V̇CO₂ slope in HFrEF and HFpEF was explained by peak exercise V_D /V_T (R²  = 0.30 and R²  = 0.50, respectively) and PaCO₂ (R²  = 0.64 and R²  = 0.28, respectively), but the relative contributions of each differed (all P < 0.01).

CONCLUSIONS

Relationships between the V̇_E /V̇CO₂ slope and both V_D /V_T and PaCO₂ are robust, but differ between HFpEF and HFrEF. Increasing V̇_E /V̇CO₂ slope appears to be strongly explained by mechanisms influential in regulating PaCO₂ in HFrEF, which contrasts with the strong role of increased V_D /V_T in HFpEF.

Cardiopulmonary Exercise Testing: What Is its Value?

Compared with traditional exercise tests, cardiopulmonary exercise testing (CPET) provides a thorough assessment of exercise integrative physiology involving the pulmonary, cardiovascular, muscular, and cellular oxidative systems. Due to the prognostic ability of key variables, CPET applications in cardiology have grown impressively to include all forms of exercise intolerance, with a predominant focus on heart failure with reduced or with preserved ejection fraction. As impaired cardiac output and peripheral oxygen diffusion are the main determinants of the abnormal functional response in cardiac patients, invasive CPET has gained new popularity, especially for diagnosing early heart failure with preserved ejection fraction and exercise-induced pulmonary hypertension. The most impactful advance has recently come from the introduction of CPET combined with echocardiography or CPET imaging, which provides basic information regarding cardiac and valve morphology and function. This review highlights modern CPET use as a single or combined test that allows the pathophysiological bases of exercise limitation to be translated, quite easily, into clinical practice.

Physiological Techniques and Pulmonary Hypertension - Left Heart Disease

Group 2 Pulmonary hypertension (PH) is associated with left heart disease (LHD;Group 2 PH) and is the most common form of PH. Group 2 PH represents an important subgroup of patients with LHD where the development of PH leads to a significant increase in morbidity and mortality. Early diagnosis may provide an opportunity to intervene and significantly delay progression. In addition to clinical suspicion, several approaches including hemodynamic assessment, exercise testing, and imaging techniques play an important role in better disease characterization and management. Here, we review the role of physiologic based hemodynamic and exercise assessments of Group 2 PH patients.

2016 Focused Update: Clinical Recommendations for Cardiopulmonary Exercise Testing Data Assessment in Specific Patient Populations

In the past several decades, cardiopulmonary exercise testing (CPX) has seen an exponential increase in its evidence base. The growing volume of evidence in support of CPX has precipitated the release of numerous scientific statements by societies and associations. In 2012, the European Association for Cardiovascular Prevention & Rehabilitation and the American Heart Association developed a joint document with the primary intent of redefining CPX analysis and reporting in a way that would streamline test interpretation and increase clinical application. Specifically, the 2012 joint scientific statement on CPX conceptualized an easy-to-use, clinically meaningful analysis based on evidence-vetted variables in color-coded algorithms; single-page algorithms were successfully developed for each proposed test indication. Because of an abundance of new CPX research in recent years and a reassessment of the current algorithms in light of the body of evidence, a focused update to the 2012 scientific statement is now warranted. The purposes of this update are to confirm algorithms included in the initial scientific statement not requiring revision, to propose revisions to algorithms included in the initial scientific statement, to propose new algorithms based on emerging scientific evidence, to further clarify the application of oxygen consumption at ventilatory threshold, to describe CPX variables with an emerging scientific evidence base, to describe the synergistic value of combining CPX with other assessments, to discuss personnel considerations for CPX laboratories, and to provide recommendations for future CPX research.