Exercise intolerance is common in people with heart failure and preserved ejection fraction (HFpEF). Right ventricular (RV) dysfunction has been shown at rest in HFpEF but little data are available ...regarding dynamic RV-pulmonary artery (PA) coupling during exercise.
Subjects with HFpEF (n = 50) and controls (n = 24) prospectively underwent invasive cardiopulmonary exercise testing using high-fidelity micromanometer catheters along with simultaneous assessment of RV and left ventricular (LV) mechanics by echocardiography. Compared with controls at rest, subjects with HFpEF displayed preserved RV systolic and diastolic mechanics (RV s' and e'), impaired LV s' and e', higher biventricular filling pressures, and higher pulmonary artery pressures. On exercise, subjects with HFpEF displayed less increase in stroke volume, heart rate, and cardiac output (CO), with blunted increase in CO relative to O
consumption (VO
). Enhancement in RV systolic and diastolic function on exercise was impaired in HFpEF compared with controls. Exercise-induced PA vasodilation was reduced in HFpEF in correlation with greater venous hypoxia. Elevations in biventricular filling pressures and limitations in CO reserve were strongly correlated with abnormal enhancement in ventricular mechanics in the RV and LV during stress.
In addition to limited LV reserve, patients with HFpEF display impaired RV reserve during exercise that is associated with high filling pressures and inadequate CO responses. These findings highlight the importance of biventricular dysfunction in HFpEF and suggest that novel therapies targeting myocardial reserve in both the left and right heart may be effective to improve clinical status.
BACKGROUND:Diagnosis of heart failure with preserved ejection fraction (HFpEF) is challenging and relies largely on demonstration of elevated cardiac filling pressures (pulmonary capillary wedge ...pressure). Current guidelines recommend use of natriuretic peptides (N-terminal pro-B type natriuretic peptide) and rest/exercise echocardiography (E/e′ ratio) to make this determination. Data to support this practice are conflicting.
METHODS:Simultaneous echocardiographic-catheterization studies were prospectively conducted at rest and during exercise in subjects with invasively proven HFpEF (n=50) and participants with dyspnea but no identifiable cardiac pathology (n=24).
RESULTS:N-Terminal pro-B type natriuretic peptide levels were below the level considered to exclude disease (≤125 pg/mL) in 18% of subjects with HFpEF. E/e′ ratio was correlated with directly measured pulmonary capillary wedge pressure at rest (r=0.63, P<0.0001) and during exercise (r=0.57, P<0.0001). Although specific, current guidelines were poorly sensitive, identifying only 34% to 60% of subjects with invasively proven HFpEF on the basis of resting echocardiographic data alone. Addition of exercise echocardiographic data (E/e′ ratio>14) improved sensitivity (to 90%) and thus negative predictive value, but decreased specificity (71%).
CONCLUSIONS:Currently proposed HFpEF diagnostic guidelines on the basis of resting data are poorly sensitive. Adding exercise E/e′ data improves sensitivity and negative predictive value but compromises specificity, suggesting that exercise echocardiography may help rule out HFpEF. These results question the accuracy of current approaches to exclude HFpEF on the basis of resting data alone and reinforce the value of exercise testing using invasive and noninvasive hemodynamic assessments to definitively confirm or refute the diagnosis of HFpEF.
CLINICAL TRIAL REGISTRATION:URLhttp://www.clinicaltrials.gov. Unique IdentifierNCT01418248.
This study sought to define the invasive hemodynamic correlates of peak oxygen consumption (Vo2) in both supine and upright exercise in heart failure with preserved ejection fraction (HFpEF) and ...evaluate its diagnostic role as a method to discriminate HFpEF from noncardiac etiologies of dyspnea (NCD).
Peak Vo2 is depressed in patients with HFpEF. The hemodynamic correlates of reduced peak Vo2 and its role in the clinical evaluation of HFpEF are unclear.
Consecutive patients with dyspnea and normal EF (N = 206) undergoing both noninvasive upright and invasive supine cardiopulmonary exercise testing were examined. Patients with invasively verified HFpEF were compared with those with NCD.
Compared with NCD (n = 72), HFpEF patients (n = 134) displayed lower peak Vo2 during upright and supine exercise. Left heart filling pressures during exercise were inversely correlated with peak Vo2 in HFpEF, even after accounting for known determinants of O2 transport according to the Fick principle. Very low upright peak Vo2 (<14 ml/kg/min) discriminated HFpEF from NCD with excellent specificity (91%) but poor sensitivity (50%). Preserved peak Vo2 (>20 ml/kg/min) excluded HFpEF with high sensitivity (90%) but had poor specificity (49%). Intermediate peak Vo2 cutoff points were associated with substantial overlap between cases and NCD.
Elevated cardiac filling pressure during exercise is independently correlated with reduced exercise capacity in HFpEF, irrespective of body position, emphasizing its importance as a novel therapeutic target. Noninvasive cardiopulmonary testing discriminates HFpEF and NCD at high and low values, but additional testing is required for patients with intermediate peak Vo2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Aims
Increases in left ventricular filling pressure are a fundamental haemodynamic abnormality in heart failure with preserved ejection fraction (HFpEF). However, very little is known ...regarding how elevated filling pressures cause pulmonary abnormalities or symptoms of dyspnoea. We sought to determine the relationships between simultaneously measured central haemodynamics, symptoms, and lung ventilatory and gas exchange abnormalities during exercise in HFpEF.
Methods and results
Subjects with invasively-proven HFpEF (n = 50) and non-cardiac causes of dyspnoea (controls, n = 24) underwent cardiac catheterization at rest and during exercise with simultaneous expired gas analysis. During submaximal (20 W) exercise, subjects with HFpEF displayed higher pulmonary capillary wedge pressures (PCWP) and pulmonary artery pressures, higher Borg perceived dyspnoea scores, and increased ventilatory drive and respiratory rate. At peak exercise, ventilation reserve was reduced in HFpEF compared with controls, with greater dead space ventilation (higher VD/VT). Increasing exercise PCWP was directly correlated with higher perceived dyspnoea scores, lower peak exercise capacity, greater ventilatory drive, worse New York Heart Association (NYHA) functional class, and impaired pulmonary ventilation reserve.
Conclusion
This study provides the first evidence linking altered exercise haemodynamics to pulmonary abnormalities and symptoms of dyspnoea in patients with HFpEF. Further study is required to identify the mechanisms by which haemodynamic derangements affect lung function and symptoms and to test novel therapies targeting exercise haemodynamics in HFpEF.
The discovery and mapping of genomic variants is an essential step in most analysis done using sequencing reads. There are a number of mature software packages and associated pipelines that can ...identify single nucleotide polymorphisms (SNPs) with a high degree of concordance. However, the same cannot be said for tools that are used to identify the other types of variants. Indels represent the second most frequent class of variants in the human genome, after single nucleotide polymorphisms. The reliable detection of indels is still a challenging problem, especially for variants that are longer than a few bases.
We have developed a set of algorithms and heuristics collectively called indelMINER to identify indels from whole genome resequencing datasets using paired-end reads. indelMINER uses a split-read approach to identify the precise breakpoints for indels of size less than a user specified threshold, and supplements that with a paired-end approach to identify larger variants that are frequently missed with the split-read approach. We use simulated and real datasets to show that an implementation of the algorithm performs favorably when compared to several existing tools.
indelMINER can be used effectively to identify indels in whole-genome resequencing projects. The output is provided in the VCF format along with additional information about the variant, including information about its presence or absence in another sample. The source code and documentation for indelMINER can be freely downloaded from www.bx.psu.edu/miller_lab/indelMINER.tar.gz .
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objectives The purpose of this study was to comprehensively examine cardiovascular reserve function with exercise in patients with heart failure and preserved ejection fraction (HFpEF). Background ...Optimal exercise performance requires an integrated physiologic response, with coordinated increases in heart rate, contractility, lusitropy, arterial vasodilation, endothelial function, and venous return. Cardiac and vascular responses are coupled, and abnormalities in several components may interact to promote exertional intolerance in HFpEF. Methods Subjects with HFpEF (n = 21), hypertension without heart failure (n = 19), and no cardiovascular disease (control, n = 10) were studied before and during exercise with characterization of cardiovascular reserve function by Doppler echocardiography, peripheral arterial tonometry, and gas exchange. Results Exercise capacity and tolerance were reduced in HFpEF compared with hypertensive subjects and controls, with lower VO2 and cardiac index at peak, and more severe dyspnea and fatigue at matched low-level workloads. Endothelial function was impaired in HFpEF and in hypertensive subjects as compared with controls. However, blunted exercise-induced increases in chronotropy, contractility, and vasodilation were unique to HFpEF and resulted in impaired dynamic ventricular-arterial coupling responses during exercise. Exercise capacity and symptoms of exertional intolerance were correlated with abnormalities in each component of cardiovascular reserve function, and HFpEF subjects were more likely to display multiple abnormalities in reserve. Conclusions HFpEF is characterized by depressed reserve capacity involving multiple domains of cardiovascular function, which contribute in an integrated fashion to produce exercise limitation. Appreciation of the global nature of reserve dysfunction in HFpEF will better inform optimal design for future diagnostic and therapeutic strategies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Cardiovascular disease is a leading cause of morbidity and mortality in males and females in the United States and globally. Cardiac rehabilitation (CR) is recommended by the American Heart ...Association/American College of Cardiology for secondary prevention for patients with cardiovascular disease. CR participation is associated with improved cardiovascular disease risk factor management, quality of life, and exercise capacity as well as reductions in hospital admissions and mortality. Despite these advantageous clinical outcomes, significant sex disparities exist in outpatient phase II CR programming. This article reviews sex differences that are present in the spectrum of care provided by outpatient phase II CR programming (ie, from referral to clinical management). We first review CR participation by detailing the sex disparities in the rates of CR referral, enrollment, and completion. In doing so, we discuss patient, health care provider, and social/environmental level barriers to CR participation with a particular emphasis on those barriers that majorly impact females. We also evaluate sex differences in the core components incorporated into CR programming (eg, patient assessment, exercise training, hypertension management). Next, we review strategies to mitigate these sex differences in CR participation with a focus on automatic CR referral, female-only CR programming, and hybrid CR. Finally, we outline knowledge gaps and areas of future research to minimize and prevent sex differences in CR programming.
Cardiac reserve is depressed in patients with heart failure and preserved ejection fraction (HFpEF). The mechanisms causing this are poorly understood.
The authors hypothesized that myocardial injury ...might contribute to the hemodynamic derangements and cardiac reserve limitations that are present in HFpEF. Markers of cardiomyocyte injury, central hemodynamics, ventricular function, and determinants of cardiac oxygen supply–demand balance were measured.
Subjects with HFpEF (n = 38) and control subjects without heart failure (n = 20) underwent cardiac catheterization, echocardiography, and expired gas analysis at rest and during exercise. Central venous blood was sampled to measure plasma high-sensitivity troponin T levels as an index of cardiomyocyte injury.
Compared with control subjects, troponins were more than 2-fold higher in subjects with HFpEF at rest and during exercise (p < 0.0001). Troponin levels were directly correlated with left ventricular (LV) filling pressures (r = 0.52; p < 0.0001) and diastolic dysfunction (r = −0.43; p = 0.002). Although myocardial oxygen demand was similar, myocardial oxygen supply was depressed in HFpEF, particularly during exercise (coronary perfusion pressure–time integral; 44 ± 9 mm Hg × s × min−1 × l × dl−1 vs. 30 ± 9 mm Hg × s × min−1 × l × dl−1; p < 0.0001), and reduced indices of supply were correlated with greater myocyte injury during exercise (r = −0.44; p = 0.0008). Elevation in troponin with exercise was directly correlated with an inability to augment LV diastolic (r = −0.40; p = 0.02) and systolic reserve (r = −0.57; p = 0.0003), greater increases in LV filling pressures (r = 0.55; p < 0.0001), blunted cardiac output response (r = −0.44; p = 0.002), and more severely depressed aerobic capacity in HFpEF.
Limitations in LV functional reserve and the hemodynamic derangements that develop secondary to these limitations during exercise in HFpEF are correlated with the severity of cardiac injury, assessed by plasma levels of troponin T. Further study is warranted to determine the mechanisms causing myocyte injury in HFpEF and the potential role of ischemia, and to identify and test novel interventions targeted to these mechanisms. (EXEC Study of Exercise and Heart Function in Patients With Heart Failure and Pulmonary Vascular Disease; NCT01418248)
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Over 50 years ago, John Wahren and Lennart Jorfeldt published a manuscript in Clinical Science where they detailed a series of studies of leg blood flow during exercise. They used a novel approach to ...indicator dye dilution: continuous arterial infusions of dye using venous samples. This technique allowed them to describe for the first time the fundamental relationships between large muscle group exercise, muscle blood flow, and pulmonary and muscle oxygen uptake. They also defined mechanical efficiency, a key measurement of muscle function. This paper formed the basis for research into muscle blood flow and exercise in health and disease and continued to be cited by modern research. In this commentary, we describe the innovations they made, the key observations that came out of their results, and the importance of this manuscript to current research.
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