Pulmonary function, cardiac function, and exercise capacity in a follow-up of patients with congestive heart failure treated with carvedilol

Iron Deficiency in Heart Failure: A Scientific Statement from the Heart Failure Society of America

Iron deficiency is present in approximately 50% of patients with symptomatic heart failure and is independently associated with worse functional capacity, lower quality of, life and increased mortality. The purpose of this document is to summarize current knowledge of how iron deficiency is defined in heart failure and its epidemiology and pathophysiology, as well as pharmacological considerations for repletion strategies. This document also summarizes the rapidly expanding array of clinical trial evidence informing when, how, and in whom to consider iron repletion.

Developments in Exercise Capacity Assessment in Heart Failure Clinical Trials and the Rationale for the Design of METEORIC-HF

Heart failure with reduced ejection fraction (HFrEF) is a highly morbid condition for which exercise intolerance is a major manifestation. However, methods to assess exercise capacity in HFrEF vary widely in clinical practice and in trials. We describe advances in exercise capacity assessment in HFrEF and a comparative analysis of how various therapies available for HFrEF impact exercise capacity. Current guideline-directed medical therapy has indirect effects on cardiac performance with minimal impact on measured functional capacity. Omecamtiv mecarbil is a novel selective cardiac myosin activator that directly increases cardiac contractility and in a phase 3 cardiovascular outcomes study significantly reduced the primary composite end point of time to first heart failure event or cardiovascular death in patients with HFrEF. The objective of the METEORIC-HF trial (Multicenter Exercise Tolerance Evaluation of Omecamtiv Mecarbil Related to Increased Contractility in Heart Failure) is to assess the effect of omecamtiv mecarbil versus placebo on multiple components of functional capacity in HFrEF. The primary end point is to test the effect of omecamtiv mecarbil compared with placebo on peak oxygen uptake as measured by cardiopulmonary exercise testing after 20 weeks of treatment. METEORIC-HF will provide state-of-the-art assessment of functional capacity by measuring ventilatory efficiency, circulatory power, ventilatory anaerobic threshold, oxygen uptake recovery kinetics, daily activity, and quality-of-life assessment. Thus, the METEORIC-HF trial will evaluate the potential impact of increased myocardial contractility with omecamtiv mecarbil on multiple important measures of functional capacity in ambulatory patients with symptomatic HFrEF. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT03759392.

Beta-blockers and inhibitors of the renin-angiotensin aldosterone system for chronic heart failure with preserved ejection fraction

BACKGROUND

Beta-blockers and inhibitors of the renin-angiotensin-aldosterone system improve survival and reduce morbidity in people with heart failure with reduced left ventricular ejection fraction (LVEF); a review of the evidence is required to determine whether these treatments are beneficial for people with heart failure with preserved ejection fraction (HFpEF).

OBJECTIVES

To assess the effects of beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, angiotensin receptor neprilysin inhibitors, and mineralocorticoid receptor antagonists in people with HFpEF.

SEARCH METHODS

We updated searches of CENTRAL, MEDLINE, Embase, and one clinical trial register on 14 May 2020 to identify eligible studies, with no language or date restrictions. We checked references from trial reports and review articles for additional studies.  SELECTION CRITERIA: We included randomised controlled trials with a parallel group design, enrolling adults with HFpEF, defined by LVEF greater than 40%.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 41 randomised controlled trials (231 reports), totalling 23,492 participants across all comparisons. The risk of bias was frequently unclear and only five studies had a low risk of bias in all domains. Beta-blockers (BBs) We included 10 studies (3087 participants) investigating BBs. Five studies used a placebo comparator and in five the comparator was usual care. The mean age of participants ranged from 30 years to 81 years. A possible reduction in cardiovascular mortality was observed (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.62 to 0.99; number needed to treat for an additional benefit (NNTB) 25; 1046 participants; three studies), however, the certainty of evidence was low. There may be little to no effect on all-cause mortality (RR 0.82, 95% CI 0.67 to 1.00; 1105 participants; four studies; low-certainty evidence). The effects on heart failure hospitalisation, hyperkalaemia, and quality of life remain uncertain. Mineralocorticoid receptor antagonists (MRAs) We included 13 studies (4459 participants) investigating MRA. Eight studies used a placebo comparator and in five the comparator was usual care. The mean age of participants ranged from 54.5 to 80 years. Pooled analysis indicated that MRA treatment probably reduces heart failure hospitalisation (RR 0.82, 95% CI 0.69 to 0.98; NNTB = 41; 3714 participants; three studies; moderate-certainty evidence). However, MRA treatment probably has little or no effect on all-cause mortality (RR 0.91, 95% CI 0.78 to 1.06; 4207 participants; five studies; moderate-certainty evidence) and cardiovascular mortality (RR 0.90, 95% CI 0.74 to 1.11; 4070 participants; three studies; moderate-certainty evidence). MRA treatment may have little or no effect on quality of life measures (mean difference (MD) 0.84, 95% CI -2.30 to 3.98; 511 participants; three studies; low-certainty evidence). MRA treatment was associated with a higher risk of hyperkalaemia (RR 2.11, 95% CI 1.77 to 2.51; number needed to treat for an additional harmful outcome (NNTH) = 11; 4291 participants; six studies; high-certainty evidence). Angiotensin-converting enzyme inhibitors (ACEIs) We included eight studies (2061 participants) investigating ACEIs. Three studies used a placebo comparator and in five the comparator was usual care. The mean age of participants ranged from 70 to 82 years. Pooled analyses with moderate-certainty evidence suggest that ACEI treatment likely has little or no effect on cardiovascular mortality (RR 0.93, 95% CI 0.61 to 1.42; 945 participants; two studies), all-cause mortality (RR 1.04, 95% CI 0.75 to 1.45; 1187 participants; five studies) and heart failure hospitalisation (RR 0.86, 95% CI 0.64 to 1.15; 1019 participants; three studies), and may result in little or no effect on the quality of life (MD -0.09, 95% CI -3.66 to 3.48; 154 participants; two studies; low-certainty evidence). The effects on hyperkalaemia remain uncertain. Angiotensin receptor blockers (ARBs) Eight studies (8755 participants) investigating ARBs were included. Five studies used a placebo comparator and in three the comparator was usual care. The mean age of participants ranged from 61 to 75 years. Pooled analyses with high certainty of evidence suggest that ARB treatment has little or no effect on cardiovascular mortality (RR 1.02, 95% 0.90 to 1.14; 7254 participants; three studies), all-cause mortality (RR 1.01, 95% CI 0.92 to 1.11; 7964 participants; four studies), heart failure hospitalisation (RR 0.92, 95% CI 0.83 to 1.02; 7254 participants; three studies), and quality of life (MD 0.41, 95% CI -0.86 to 1.67; 3117 participants; three studies). ARB was associated with a higher risk of hyperkalaemia (RR 1.88, 95% CI 1.07 to 3.33; 7148 participants; two studies; high-certainty evidence). Angiotensin receptor neprilysin inhibitors (ARNIs) Three studies (7702 participants) investigating ARNIs were included. Two studies used ARBs as the comparator and one used standardised medical therapy, based on participants' established treatments at enrolment. The mean age of participants ranged from 71 to 73 years. Results suggest that ARNIs may have little or no effect on cardiovascular mortality (RR 0.96, 95% CI 0.79 to 1.15; 4796 participants; one study; moderate-certainty evidence), all-cause mortality (RR 0.97, 95% CI 0.84 to 1.11; 7663 participants; three studies; high-certainty evidence), or quality of life (high-certainty evidence). However, ARNI treatment may result in a slight reduction in heart failure hospitalisation, compared to usual care (RR 0.89, 95% CI 0.80 to 1.00; 7362 participants; two studies; moderate-certainty evidence). ARNI treatment was associated with a reduced risk of hyperkalaemia compared with valsartan (RR 0.88, 95% CI 0.77 to 1.01; 5054 participants; two studies; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

There is evidence that MRA and ARNI treatment in HFpEF probably reduces heart failure hospitalisation but probably has little or no effect on cardiovascular mortality and quality of life. BB treatment may reduce the risk of cardiovascular mortality, however, further trials are needed. The current evidence for BBs, ACEIs, and ARBs is limited and does not support their use in HFpEF in the absence of an alternative indication. Although MRAs and ARNIs are probably effective at reducing the risk of heart failure hospitalisation, the treatment effect sizes are modest. There is a need for improved approaches to patient stratification to identify the subgroup of patients who are most likely to benefit from MRAs and ARNIs, as well as for an improved understanding of disease biology, and for new therapeutic approaches.

Psoriasis and Respiratory Comorbidities: The Added Value of Fraction of Exhaled Nitric Oxide as a New Method to Detect, Evaluate, and Monitor Psoriatic Systemic Involvement and Therapeutic Efficacy

Psoriasis is a chronic inflammatory systemic disease characterized by a wide range of comorbidities. Respiratory comorbidities are currently poorly characterized and with discordant results. The systemic state of inflammation caused by psoriasis acts de novo on respiratory tissues and amplifies preexisting inflammation from asthma or chronic obstructive pulmonary disease. Because the lungs act as a gas exchanger between the internal and external environment, the impact of chronic psoriasis inflammation may be easily assessed through the analysis of exhaled breath. The fraction of exhaled nitric oxide test (FeNO) is a potential noninvasive solution that can provide quantitative and qualitative indices of respiratory airway inflammation. FeNO is routinely used to screen and manage asthmatic patients. Recent pilot studies contain encouraging data that underscore its possible use with systemic inflammatory nonpulmonary diseases, such as psoriasis. FeNO may therefore be a useful tool to evaluate underestimated airway inflammation and at the same time globally evaluate the impact of systemically antipsoriatic therapies.

Beta-blockers and inhibitors of the renin-angiotensin aldosterone system for chronic heart failure with preserved ejection fraction

BACKGROUND

Beta-blockers and inhibitors of the renin-angiotensin aldosterone system improve survival and reduce morbidity in people with heart failure with reduced left ventricular ejection fraction. There is uncertainty whether these treatments are beneficial for people with heart failure with preserved ejection fraction and a comprehensive review of the evidence is required.

OBJECTIVES

To assess the effects of beta-blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, angiotensin receptor neprilysin inhibitors, and mineralocorticoid receptor antagonists in people with heart failure with preserved ejection fraction.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and two clinical trial registries on 25 July 2017 to identify eligible studies. Reference lists from primary studies and review articles were checked for additional studies. There were no language or date restrictions.

SELECTION CRITERIA

We included randomised controlled trials with a parallel group design enrolling adult participants with heart failure with preserved ejection fraction, defined by a left ventricular ejection fraction of greater than 40 percent.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion and extracted data. The outcomes assessed included cardiovascular mortality, heart failure hospitalisation, hyperkalaemia, all-cause mortality and quality of life. Risk ratios (RR) and, where possible, hazard ratios (HR) were calculated for dichotomous outcomes. For continuous data, mean difference (MD) or standardised mean difference (SMD) were calculated. We contacted trialists where neccessary to obtain missing data.

MAIN RESULTS

37 randomised controlled trials (207 reports) were included across all comparisons with a total of 18,311 participants.Ten studies (3087 participants) investigating beta-blockers (BB) were included. A pooled analysis indicated a reduction in cardiovascular mortality (15% of participants in the intervention arm versus 19% in the control arm; RR 0.78; 95% confidence interval (CI) 0.62 to 0.99; number needed to treat to benefit (NNTB) 25; 1046 participants; 3 studies). However, the quality of evidence was low and no effect on cardiovascular mortality was observed when the analysis was limited to studies with a low risk of bias (RR 0.81; 95% CI 0.50 to 1.29; 643 participants; 1 study). There was no effect on all-cause mortality, heart failure hospitalisation or quality of life measures, however there is uncertainty about these effects given the limited evidence available.12 studies (4408 participants) investigating mineralocorticoid receptor antagonists (MRA) were included with the quality of evidence assessed as moderate. MRA treatment reduced heart failure hospitalisation (11% of participants in the intervention arm versus 14% in the control arm; RR 0.82; 95% CI 0.69 to 0.98; NNTB 41; 3714 participants; 3 studies; moderate-quality evidence) however, little or no effect on all-cause and cardiovascular mortality and quality of life measures was observed. MRA treatment was associated with a greater risk of hyperkalaemia (16% of participants in the intervention group versus 8% in the control group; RR 2.11; 95% CI 1.77 to 2.51; 4291 participants; 6 studies; high-quality evidence).Eight studies (2061 participants) investigating angiotensin converting enzyme inhibitors (ACEI) were included with the overall quality of evidence assessed as moderate. The evidence suggested that ACEI treatment likely has little or no effect on cardiovascular mortality, all-cause mortality, heart failure hospitalisation, or quality of life. Data for the effect of ACEI on hyperkalaemia were only available from one of the included studies.Eight studies (8755 participants) investigating angiotensin receptor blockers (ARB) were included with the overall quality of evidence assessed as high. The evidence suggested that treatment with ARB has little or no effect on cardiovascular mortality, all-cause mortality, heart failure hospitalisation, or quality of life. ARB was associated with an increased risk of hyperkalaemia (0.9% of participants in the intervention group versus 0.5% in the control group; RR 1.88; 95% CI 1.07 to 3.33; 7148 participants; 2 studies; high-quality evidence).We identified a single ongoing placebo-controlled study investigating the effect of angiotensin receptor neprilysin inhibitors (ARNI) in people with heart failure with preserved ejection fraction.

AUTHORS' CONCLUSIONS

There is evidence that MRA treatment reduces heart failure hospitalisation in heart failure with preserverd ejection fraction, however the effects on mortality related outcomes and quality of life remain unclear. The available evidence for beta-blockers, ACEI, ARB and ARNI is limited and it remains uncertain whether these treatments have a role in the treatment of HFpEF in the absence of an alternative indication for their use. This comprehensive review highlights a persistent gap in the evidence that is currently being addressed through several large ongoing clinical trials.

The effect of diuresis on extravascular lung water and pulmonary function in acute decompensated heart failure

Aims

The effect of extravascular lung water (EVLW) and relationship to functional status as a result of acute decompensated heart failure (ADHF) are not well understood. We sought to quantify changes in clinical variables, EVLW, airway anatomy, spirometry, and diffusing capacity for carbon monoxide before and after treatment for ADHF.

Methods and results

Fifteen patients were recruited within 24 h of hospital admission. Spirometry, diffusing capacity for carbon monoxide, and surrogates of EVLW by computed tomography were measured and were then repeated within 24 h of discharge. From the computed tomography (CT) scan, surrogates of EVLW were calculated from the distribution of CT attenuation of the lung tissue. Airways were segmented using the vida apollo software. Patients were hospitalized for 4.6 ± 2.1 days, had 10 ± 4.8 L of fluid removed (7.0 ± 4.2 L between study visits), and lost 7.1 ± 4.9 kg. Patients had significant clearance of fluid from the lungs (per cent change: mean, 4.2 ± 6.1%; skew, 17.5 ± 27.0%; kurtosis, 37.6 ± 56.7%; full‐width half‐maximum, 10.2 ± 13.5%). Static lung volumes and maximal flows improved significantly (per cent change: forced vital capacity, 14.5 ± 13.6%; forced expiratory volume in 1 s, 15.9 ± 14.0%; forced expiratory flow at 25–75% of forced vital capacity, 27.2 ± 42.9%). The ratio of membrane conductance to capillary blood volume improved significantly (per cent change: alveolar–capillary membrane conductance/capillary blood volume, 23.4 ± 22.8%). Weight loss during hospitalization was significantly correlated with improved spirometry and diffusing capacity.

Conclusions

Extravascular lung water contributes to the pulmonary congestive syndrome in ADHF patients, and its clearance is an important component of the improvement in pulmonary function as a result of inpatient treatment.

Heart Failure with Myocardial Recovery - The Patient Whose Heart Failure Has Improved: What Next?

In an important number of heart failure (HF) patients substantial or complete myocardial recovery occurs. In the strictest sense, myocardial recovery is a return to both normal structure and function of the heart. HF patients with myocardial recovery or recovered ejection fraction (EF; HFrecEF) are a distinct population of HF patients with different underlying etiologies, demographics, comorbidities, response to therapies and outcomes compared to HF patients with persistent reduced (HFrEF) or preserved ejection fraction (HFpEF). Improvement of left ventricular EF has been systematically linked to improved quality of life, lower rehospitalization rates and mortality. However, mortality and morbidity in HFrecEF patients remain higher than in the normal population. Also, persistent abnormalities in biomarker and gene expression profiles in these patients lends weight to the hypothesis that pathological processes are ongoing. Currently, there remains a lack of data to guide the management of HFrecEF patients. This review will discuss specific characteristics, pathophysiology, clinical implications and future needs for HFrecEF.

Glomerular filtration rate affects interpretation of pulmonary function test in a Korean general population: results from the Korea National Health and Nutrition Examination Survey 2010 to 2012

BACKGROUND/AIMS

The pulmonary abnormalities (principally restrictive abnormalities) are characteristic of renal transplant recipients or those with end-stage renal disease. Our aim was to explore whether the prevalence of spirometric abnormalities was influenced by the estimated glomerular filtration rates (GFRs) in a Korean general population.

METHODS

We used data obtained during the 2010 to 2012 Korean National Health and Nutrition Examination Survey, a national cross-sectional survey. We analyzed data from subjects for whom spirometric assays and estimated GFRs were of acceptable quality.

RESULTS

A total of 8,809 subjects (3,868 male and 4,941 female) was included. In both males and females with GFR values < 60 mL/min/1.73 m², the linear trends toward the presence of obstructive and restrictive patterns were significant. However, the percent predicted forced vital capacity (FVC) decreased with a decline in the estimated GFR, but only in males (p for trend < 0.0031). Multivariate linear regression analysis showed a decline in the estimated GFR was independently associated with falls in the percent predicted FVC and the forced expiratory volume in 1 second/FVC ratio in both males and females. However, the percent predicted FVC was independently predictive only in males (p = 0.002).

CONCLUSIONS

Impaired pulmonary function was associated with a decline in the estimated GFR. The percent predicted FVC decrease paralleled the decline in estimated GFR in male only. Careful interpretation of pulmonary function test data is required in patients with decreased GFRs or impaired renal function, especially males.

A Review of the External Validity of Clinical Trials with Beta-Blockers in Heart Failure

BACKGROUND

Beta-blockers (BBs) are the mainstay prognostic medication for all stages of chronic heart failure (CHF). There are many classes of BBs, each of which has varying levels of evidence to support its efficacy in CHF. However, most CHF patients have one or more comorbid conditions such as diabetes, renal impairment, and/or atrial fibrillation. Patient enrollment to randomized controlled trials (RCTs) often excludes those with certain comorbidities, particularly if the symptoms are severe. Consequently, the extent to which evidence drawn from RCTs is generalizable to CHF patients has not been well described. Clinical guidelines also underrepresent this point by providing generic advice for all patients. The aim of this review is to examine the evidence to support the use of BBs in CHF patients with common comorbid conditions.

METHODS

We searched MEDLINE, PubMed, and the reference lists of reviews for RCTs, post hoc analyses, systematic reviews, and meta-analyses that report on use of BBs in CHF along with patient demographics and comorbidities.

RESULTS

In total, 38 studies from 28 RCTs were identified, which provided data on six BBs against placebo or head to head with another BB agent in ischemic and nonischemic cardiomyopathies. Several studies explored BBs in older patients. Female patients and non-Caucasian race were underrepresented in trials. End points were cardiovascular hospitalization and mortality. Comorbid diabetes, renal impairment, or atrial fibrillation was detailed; however, no reference to disease spectrum or management goals as a focus could be seen in any of the studies. In this sense, enrollment may have limited more severe grades of these comorbidities.

CONCLUSIONS

RCTs provide authoritative information for a spectrum of CHF presentations that support guidelines. RCTs may provide inadequate information for more heterogeneous CHF patient cohorts. Greater Phase IV research may be needed to fill this gap and inform guidelines for a more global patient population.

Exertional dyspnoea in chronic heart failure: the role of the lung and respiratory mechanical factors

Exertional dyspnoea is among the dominant symptoms in patients with chronic heart failure and progresses relentlessly as the disease advances, leading to reduced ability to function and engage in activities of daily living. Effective management of this disabling symptom awaits a better understanding of its underlying physiology.

Cardiovascular factors are believed to play a major role in dyspnoea in heart failure patients. However, despite pharmacological interventions, such as vasodilators or inotropes that improve central haemodynamics, patients with heart failure still complain of exertional dyspnoea. Clearly, dyspnoea is not determined by cardiac factors alone, but likely depends on complex, integrated cardio-pulmonary interactions.

A growing body of evidence suggests that excessively increased ventilatory demand and abnormal “restrictive” constraints on tidal volume expansion with development of critical mechanical limitation of ventilation, contribute to exertional dyspnoea in heart failure. This article will offer new insights into the pathophysiological mechanisms of exertional dyspnoea in patients with chronic heart failure by exploring the potential role of the various constituents of the physiological response to exercise and particularly the role of abnormal ventilatory and respiratory mechanics responses to exercise in the perception of dyspnoea in patients with heart failure.

Endothelial dysfunction and lung capillary injury in cardiovascular diseases

Cardiac dysfunction of both systolic and diastolic origins leads to increased left atrial pressure, lung capillary injury and increased resistance to gas transfer. Acutely, pressure-induced trauma disrupts the endothelial and alveolar anatomical configuration and definitively causes an impairment of cellular pathways involved in fluid-flux regulation and gas exchange efficiency, a process well identified as stress failure of the alveolar-capillary membrane. In chronic heart failure (HF), additional stimuli other than pressure may trigger the true remodeling process of capillaries and small arteries characterized by endothelial dysfunction, proliferation of myofibroblasts, fibrosis and extracellular matrix deposition. In parallel there is a loss of alveolar gas diffusion properties due to the increased path from air to blood (thickening of extracellular matrix) and loss of fine molecular mechanism involved in fluid reabsorption and clearance. Deleterious changes in gas transfer not only reflect the underlying lung tissue damage but also portend independent prognostic information and may play a role in the pathogenesis of exercise limitation and ventilatory abnormalities observed in these patients. Few currently approved treatments for chronic HF have the potential to positively affect structural remodeling of the lung capillary network; angiotensin-converting enzyme inhibitors are one of the few currently established options. Recently, more attention has been paid to novel therapies specifically targeting the nitric oxide pathway as a suitable target to improve endothelial function and permeability as well as alveolar gas exchange properties.

Effect of physical training on ventilatory patterns during exercise in patients with heart disease

BACKGROUND

Exercise training is known to improve the shortness of breath experienced by patients with heart disease when the ventilatory pattern becomes abnormal during exercise. However, the precise relationship between breathing patterns and the effect of exercise training has not been elucidated to date. We evaluated the relationship between the effect of exercise training on exercise tolerance and the amelioration of the ventilatory response during exercise in such patients.

METHODS AND RESULTS

Patients with heart disease (n=170) underwent cardiopulmonary exercise testing twice (pre- and postexercise training for 3-6 months). They were divided into the exercise training group (Group E, n=123) and control group (Group C, n=47). Regression line relating tidal volume to respiratory rate (TV-RR slope) during a ramp protocol below the inflection point was regarded as an indicator of rapid ventilation. Tidal volume after the inflection point was regarded as an indicator of shallow ventilation (TV at plateau). The TV-RR slope and TV at plateau improved after exercise training from 94.8±45.9 to 129.9±69.5 (p<0.001) and from 1473.6±321.9mL to 1673.2±355.1mL (p<0.001), respectively, in Group E. In contrast, no improvement was evident in Group C. In total, %anaerobic threshold (%AT) [AT improving ratio=(post-AT-pre-AT)/pre-AT×100] was positively correlated with both %TV-RR slope [TV-RR slope improving ratio=(post-TV-RR slope-pre-TV-RR slope)/pre-TV-RR slope×100] (r=0.60) and %TV at plateau [TV at plateau improving ratio=(post-TV at plateau-pre-TV at plateau)/pre-TV at plateau×100] (r=0.51).

CONCLUSION

Exercise training improved the rapidness and depth of breathing during exercise. Therefore, improvement of abnormal ventilatory patterns is correlated with exercise tolerance.

Carvedilol: use in chronic heart failure

Carvedilol is a beta-adrenergic antagonist with vasodilatory properties (alpha1-antagonism), which has been extensively evaluated in the treatment of patients with heart failure. In patients with chronic heart failure carvedilol improves left-ventricular (LV) ejection fraction over 6 to 12 months of treatment, and attenuates LV remodelling. Large-scale randomised, placebo controlled trials involving more than 4000 patients with chronic heart failure have demonstrated that carvedilol improves survival and reduces hospitalizations. Comparative studies with metoprolol in patients with heart failure have suggested that carvedilol may be associated with greater survival benefit although differences in the preparation of metoprolol have left uncertainty in this area. Carvedilol has a high safety profile and the clinical benefits appear maintained across a wide range of patients with comorbidities such as diabetes and renal failure. Carvedilol has also been shown to attenuate LV remodeling and improve clinical outcomes in patients with LV dysfunction and/or heart failure following acute myocardial infarction. As a result of these data, carvedilol is recommended for treatment of patients with heart failure in heart-failure guidelines. This evidence-based treatment should be widely implemented to ensure that patients with heart failure receive appropriate medical therapy.

Gas exchange consequences of left heart failure

This review explores the pathophysiology of gas exchange abnormalities arising consequent to either acute or chronic elevation of pulmonary venous pressures. The initial experimental studies of acute pulmonary edema outlined the sequence of events from lymphatic congestion with edema fluid to frank alveolar flooding and its resultant hypoxemia. Clinical studies of acute heart failure (HF) suggested that hypoxemia was associated only with the final stage of alveolar flooding. However, in patients with chronic heart failure and normal oxygenation, hypoxemia could be produced by the administration of potent pulmonary vasodilators, suggesting that hypoxic pulmonary vasoconstriction is an important reflex for these patients. Patients with chronic left HF commonly manifest a reduced diffusing capacity, an abnormality that appears to be a consequence of chronic elevation of left atrial pressure. That reduction in diffusing capacity does not appear to be primarily attributable to increases in lung water but is improved by any sustained treatment that improves overall cardiac function. Patients with heart failure may also manifest an abnormally elevated VE/VCO2 during exercise, and that exercise ventilation abnormality arises as a consequence of both alveolar hyperventilation and elevated physiologic dead space. That elevated exercise VE/VCO2 in an HF patient has proven to be a powerful predictor of an adverse outcome and hence it has received sustained attention in the HF literature. At least three of the classes of drugs used to treat HF will normalize the exercise VE/VCO2, suggesting that the excessive ventilation response may be linked to elevated sympathetic activity.

Current perspectives on treatment of hypertensive patients with chronic obstructive pulmonary disease

Systemic hypertension and chronic obstructive pulmonary disease (COPD) frequently coexist in the same patient, especially in the elderly. Today, a wide variety of antihypertensive drugs with different mechanisms of action are available to the prescribing physician. In addition, combination drugs for hypertension are becoming increasingly popular. Certain antihypertensive drugs can affect pulmonary function. Therefore the management of such patients can present therapeutic challenges. We have examined the literature pertaining to the use of antihypertensive drugs in patients with systemic hypertension and coexisting COPD. Although data are often limited or of poor quality, we have attempted to review and then provide recommendations regarding the use of all the specific classes of antihypertensive drug therapies including combination drugs in patients with COPD. The antihypertensive agents reviewed include diuretics, aldosterone receptor blockers, beta blockers, combined alpha and beta blockers, angiotensin-converting enzyme inhibitors, angiotensin II antagonists, calcium channel blockers, alpha-1 blockers, centrally acting drugs, direct vasodilators, and combinations of these drugs. Of these classes, calcium channel blockers and angiotensin II antagonists appear to be the best initial choices if hypertension is the only indication for treatment. However, the limited data available on many of these drugs suggest that additional studies are needed to more precisely determine the best treatment choices in this widely prevalent patient group.

Exhaled nitric oxide (FENO) in non-pulmonary diseases

Exhaled nitric oxide (F(E)NO) represents the only exhaled biomarker that has reached clinical practice even in primary care settings, due to the non-invasiveness of its assessment and ease of repeat measurements, even in patients with severe airflow obstruction. While F(E)NO has been suggested as a readily determined biomarker that can aid in the diagnosis and management of asthma, its potential role in pathophysiology of non-pulmonary diseases is less clear and therefore remains to be established. The purpose of the present review is to highlight the current literature investigating the use of F(E)NO in the diagnosis and management of non-pulmonary diseases.

β-Blockers in heart failure: benefits of β-blockers according to varying male proportions of study patients

BACKGROUND

In patients with heart failure (HF), b-blockers reduce mortality. It's not known whether the beneficial effects of the b-blockers were associated with the differing male proportions of study patients. It also remains to be clarified regarding the true beneficial effects of the 3 b-blockers recommended by the guideline on mortality in the real world.

HYPOTHESIS

The benefits of b-blockers in HF patients were sex-related different.

METHODS

Randomized, placebo controlled clinical trials were included if they evaluated the beneficial effects of the three b-blockers on mortality and on hospital admissions on an intention-to-treat basis, and lasted at least 3 months.

RESULTS

Twenty-eighty trials with 14,829 patients were included. The b-blockers significantly reduced all cause mortality by 29.6%, cardiac death by 29.8%, sudden death by 49.4%, respectively. The magnitude of benefits of b-blockers in HF patients was increased with the increased male proportion. A similar magnitude of reduction in all cause mortality was observed among the three b blockers. A trend toward to reduced cardiac death was observed among the three b blockers, but only in bisoprolol was this statistically different (RR, 0.72; 95%CI, [0.59-0.87]). Metoprolol was significantly superior to carvedilol (P = 0.008) or bisoprolol (P = 0.034) in reduced sudden death.

CONCLUSIONS

In patients with HF, the 3 commonly used b-blockers significantly reduced mortality. Greater benefits of b-blockers were observed in the higher male proportion studies. The metoprolol was significantly superior to carvedilol or bisoprolol in reduced sudden death. Additional trials are required to determine whether the benefits of b-blockers will be observed in female HF patients.

Drug and Device Effects on Peak Oxygen Consumption, 6-Minute Walk Distance, and Natriuretic Peptides as Predictors of Therapeutic Effects on Mortality in Patients With Heart Failure and Reduced Ejection Fraction

Background—

Although peak oxygen consumption (peak V o 2 ), 6-minute walk distance (6MW), and natriuretic peptides (BNP and NT-proBNP) are predictors of mortality in heart failure (HF) patients, it is not known whether therapy-induced changes in these measures can predict therapeutic effect on mortality. The objective of this analysis is to quantitatively assess the relationship between therapeutic effects on commonly proposed short-term markers in HF trials and therapeutic effects on long-term outcome in patients with HF and left ventricular dysfunction.

Methods and Results—

We identified drug or device therapies for which there exists at least 1 randomized, controlled trial (RCT) assessing mortality over at least 6 months in at least 500 patients. For each of these therapies, we identified RCTs assessing the short-term changes in V o 2 , 6MW, BNP, and NT-proBNP (few of the mortality RCTs assessed the short-term changes in markers). For each intervention, we calculated the odds ratio for mortality (using random effect meta-analysis when necessary), as well as the trial level average drug- or device-induced change in the markers. We assessed the correlation between the odds ratio for death with the placebo-corrected change in the functional parameter or biomarker across the interventions. We identified mortality RCTs of 27 distinct therapies (n=73 267 patients) with a median follow-up of 19 months, that directed the search for RCTs of the effect of those interventions on the functional markers and biomarkers. There were 54 peak V o 2 trials (n=4646 patients), 34 6MW trials (n=6995 patients), 15 BNP trials (n=7233), and 6 NT-proBNP trials (n=1946) included in this analysis. There was no significant correlation between the average therapy-induced placebo-corrected change in peak V o 2 and the odds ratio for mortality ( r =0.158, P =0.26). Increased drug or device-induced average change in 6MW was correlated with increased odds ratio for mortality ( r =0.373, P =0.036). There was no significant correlation between the average therapy-induced, placebo-corrected change in the natriuretic peptides and the odds ratio for mortality (BNP: r =−0.065, P =0.82, NT-proBNP: r =−0.667, P =0.15). There was no apparent relation between change in the functional parameter or biomarker and categorical effect on mortality.

Conclusions—

This analysis, limited to trial level data from different therapeutic eras, suggests that drug- or device-induced effects on peak V o 2 , 6MW, and natriuretic peptides found in short-term trials do not predict the corresponding average long-term therapeutic effects on mortality for patients with HF and left ventricular dysfunction.

Excess ventilation during exercise and prognosis in chronic heart failure

Excess ventilation during exercise with accompanying dyspnea is characteristic of chronic heart failure (CHF), and these patients often exhibit increased Ve relative to the Vco(2) compared with normal subjects. This can be measured in several ways, including using such variables as the slope of Ve versus Vco(2), the lowest ratio of Ve/Vco(2), and the ratio of Ve/Vco(2) at the lactic acidosis threshold or peak exercise. There is now considerable evidence that the degree of excess ventilation during exercise in patients with CHF is a robust predictor of outcome and identifies higher-risk patients requiring aggressive treatment, including heart transplantation. The mechanism of excess ventilation in patients with CHF during exercise is not completely understood. It may be related to enhanced output of chemoreceptors or peripheral muscle ergoreceptors, increased dead space/Vt ratio due to increased contribution of high ventilation-perfusion lung regions or rapid shallow breathing caused by earlier onset of lactic acidosis, or likely resulting from a combination of these causes.

Effects of interval exercise training on respiratory drive in patients with chronic heart failure

BACKGROUND

Patients with chronic heart failure (CHF) suffer from ventilatory abnormalities. This study examined the effects of interval exercise training on the respiratory drive in CHF patients.

METHODS

Forty-six clinically stable CHF patients (38 males/8 women, mean age = 53 +/- 11 years) participated in an exercise rehabilitation program (ERP) 3 times/week, for 12 weeks by interval training modality with or without the addition of resistance training. All patients underwent symptom-limited cardiopulmonary exercise testing (CPET), and measurements of mouth occlusion pressure at 100 ms (P(0.1)) and maximum inspiratory muscle strength (P(Imax)) before and after ERP. Respiratory drive was estimated by mouth occlusion pressure P(0.1) and P(0.1)/P(Imax) ratio at rest, and the ventilatory pattern by resting mean inspiratory flow (V(T)/T(I)) and by V(T)/T(I) at identical CPET workloads, before and after ERP. We also studied a control non exercising group of 11 patients (8 men and 3 women).

RESULTS

P(0.1) at rest decreased from 3.04 +/- 1.52 to 2.62 +/- 0.9 cmH(2)O (p = 0.015), P(0.1)/P(Imax) % at rest from 4.56 +/- 3.73 to 3.69 +/- 2.03 (p = 0.006), resting V(T)/T(I) from 0.44 +/- 0.10 to 0.41 +/- 0.10 l/s (p = 0.014), and V(T)/T(I) at identical work rate from 2.13 +/- 0.59 to 1.93 +/- 0.58 l/s (p = 0.001) after ERP. VO(2) at peak exercise increased from 16.3 +/- 4.8 to 18.5 +/- 5.3 ml/kg/min (p < 0.001) in the exercise group. No improvement was noted in the control group.

CONCLUSIONS

ERP by interval training improves the respiratory drive and ventilatory pattern at rest and during exercise in CHF patients.

Quantitative evaluation of drug or device effects on ventricular remodeling as predictors of therapeutic effects on mortality in patients with heart failure and reduced ejection fraction: a meta-analytic approach

OBJECTIVES

The purpose of this study was to quantitatively assess the relationship between therapy-induced changes in left ventricular (LV) remodeling and longer-term outcomes in patients with left ventricular dysfunction (LVD).

BACKGROUND

Whether therapy-induced changes in left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) are predictors of mortality in patients with LVD is not established.

METHODS

Searches for randomized controlled trials (RCTs) were conducted to identify drug or device therapies for which an effect on mortality in patients with LVD was studied in at least 1 RCT of > or = 500 patients (mortality trials). Then, all RCTs involving those therapies were identified in patients with LVD that described changes in LVEF and/or volumes over time (remodeling trials). We examined whether the magnitude of remodeling effects is associated with the odds ratios for death across all therapies or associated with whether the odds ratio for mortality was favorable, neutral, or adverse (i.e., statistically significantly decreased, nonsignificant, or statistically significantly increased odds for mortality, respectively).

RESULTS

Included were 30 mortality trials of 25 drug/device therapies (n = 69,766 patients; median follow-up 17 months) and 88 remodeling trials of the same therapies (n = 19,921 patients; median follow-up 6 months). The odds ratio for death in the mortality trials was correlated with drug/device effects on LVEF (r = -0.51, p < 0.001), EDV (r = 0.44, p = 0.002), and ESV (r = 0.48, p = 0.002). In (ordinal) logistic regressions, the odds for neutral or favorable effects in the mortality RCTs increased with mean increases in LVEF and with mean decreases in EDV and ESV in the remodeling trials.

CONCLUSIONS

In patients with LVD, short-term trial-level therapeutic effects of a drug or device on LV remodeling are associated with longer-term trial-level effects on mortality.

Is target dose of beta-blocker more important than achieved heart rate or heart rate change in patients with systolic chronic heart failure?

Beta-blockers (BBs) are mandatory therapy for patients with systolic chronic heart failure (CHF). However, it is uncertain whether target dose of these agents is more important than the achievement of target heart rate (HR) in maximizing the benefits of these agents. To test this, we obtained ECG absolute HR from patients with systolic CHF, together with consecutive left ventricular ejection fraction (EF) measures at least 3 months apart. Patients were divided into those who achieved target dose for beta-blocker and/or target absolute HR of < or = 60 beats per minute (bpm) and target change in HR (>10 bpm reduction) with increasing dose. Baseline ejection fraction (EF) was similar across all groups. Patients with absolute or change in HR at target achieved a greater change in EF than those not at target (P= 0.027 and P= 0.012, respectively). In contrast, those who achieved target dose did not achieve a significantly greater improvement in EF than those not at target dose (P= 0.81). Similarly for absolute EF, patients at target HR or target change in HR achieved a greater EF increase than those achieving target dose. Based on these data, target HR or change in HR appears to be more critical to improvement in EF than target dose in CHF patients. Therefore, achieving an absolute HR or change in HR with BBs may be more important than target dose in maximizing benefits of BBs in this setting.

Is there a difference between patients with peak oxygen consumption below 10 ml/kg/min versus between 10 and 14 ml/kg/min? Does the "Grey Zone" really exist?

BACKGROUND

Cardiopulmonary exercise testing is an important component of evaluation when orthotopic heart transplantation (OHT) is considered for chronic heart failure (CHF) patients. However there is a question about the accuracy of interpretations of peak oxygen consumption (VO(2)max) used at present.

MATERIALS AND METHODS

We analyzed 302 CHF patients stratified into 3 groups according to VO(2)max (mL/kg/min): group 1 = <10 (n = 37); group 2 = 10-14 (n = 121) and group 3 = >14 (n = 144). We compared the mortality rate, the OHT rate, time to OHT, time to death and pulmonary function tests (PFT) among the groups using ANOVA Kruskal-Wallis tests for analysis in Statistica 7.1.

RESULTS

No important differences were observed between groups 1 and 2 (P > .05), but first in comparison with group 3 (P < .05) in terms of mortality (48.6% vs 33.1% vs 21.5%), number of OHT (24.3% vs 32.2% vs 14.6%), time to death (15.4 vs 16.6 vs 34.4 months) or PFT results (forced expiratory volume in the first second forced vital capacity and peak expiratory flow, all as direct or as percent of normal values). In contrast, time to OHT (4.6 vs 6.9 vs 10.9 months) and percent of normal vital capacity (72% vs 81% vs 91%) differed significantly among all groups (P < .05).

CONCLUSION

Patients with VO(2)max between 10 and 14 or <10 mL/kg/min are at similar risk of death.

Effect of biventricular pacing on ventilatory and perceptual responses to exercise in patients with stable chronic heart failure

Despite the growing evidence supporting the use of biventricular cardiac resynchronization therapy (CRT) in patients with chronic heart failure (CHF), the mechanisms whereby acute hemodynamic improvements lead to improved exertional dyspnea are not precisely known. We hypothesized that improved cardiac function and ventilation-perfusion relations following CRT would reduce ventilatory demand, thereby improving dynamic operating lung volumes and enhancing tidal volume expansion during exercise. This, in turn, would be expected to reduce perceived exertional dyspnea and contribute to improved exercise performance. In a randomized, double-blind, crossover study, we compared cardiovascular, metabolic, ventilatory responses (breathing pattern, operating lung volumes, pulmonary gas exchange) and exertional symptoms in seven stable CHF patients who undertook incremental cardiopulmonary cycle exercise test with CRT switched to the “on” (CRTon) or “off” (CRToff) modality. Following CRTon, peak oxygen uptake was significantly increased by 15%, and dyspnea ratings were lower for a given work rate (at work rate of 40 W, dyspnea = 1 ± 0.4 vs. 2.5 ± 0.9 Borg units, P < 0.05) and ventilation (at ventilation of 31 l/min, dyspnea = 2 ± 0.7 vs. 3.3 ± 1.1 Borg units, P < 0.05). CRTon was associated with improvements in ventilatory threshold, oxygen pulse, and oxygen uptake/work rate relationships (10.2 ± 1 vs. 7.9 ± 1.3 ml·min−1·W−1, P < 0.05). CRTon reduced the ventilatory requirement during exercise as well as the steepness of ventilation-CO2 production slope (35 ± 4 vs. 45 ± 7, P < 0.05). Changes in end-expiratory lung volume during exercise were less with CRTon than with CRToff (0.12 vs. 0.37 liter, P < 0.05), and breathing pattern was correspondingly slower and deeper. Biventricular pacing improved all noninvasive indexes of cardiac function and oxygen delivery during exercise. The decreased ventilatory demand, improved dynamic operating lung volumes, and the increased ability to expand tidal volume during exercise are potential factors in the reduction of exertional dyspnea.

Effects of carvedilol on left ventricular function and oxidative stress in infants and children with idiopathic dilated cardiomyopathy: a 12-month, two-center, open-label study

OBJECTIVES

This study was conducted to determine the effects of carvedilol adjunct to standard treatment on left ventricular function (LVF), estimated as ejection fraction (EF) and fractional shortening (FS) on echocardiography, in children with idiopathic dilated cardiomyopathy (DCM). A secondary end point was to characterize the antioxidant potential of carvedilol.

METHODS

Hospitalized children aged <or=16 years with clinically stable DCM and advanced congestive heart failure (HF) with modified New York Heart Association Classification for Children (NYHAC) functional classes II to IV and EF <40% were enrolled in this prospective, 12-month, 2-center, open-label study. Oral carvedilol was added to a standard regimen of an angiotensin-converting enzyme inhibitor, a diuretic, and digoxin in a dose-escalation design. Systolic and diastolic blood pressure (BP), heart rate (HR), and modified NYHAC were assessed before (baseline) and at 1, 3, 6, and 12 months of adjunct carvedilol treatment. EF and FS were analyzed before and at 6 and 12 months of carvedilol treatment. At each study visit, tolerability was assessed in terms of adverse events (AEs), treatment emergent signs and symptoms, physical examination including vital sign measurement (BP, HR, and body temperature), and laboratory analysis. Antioxidative enzyme activity was evaluated by measuring erythrocyte copper/zinc superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GR) activity at baseline and 1, 3, 6, and 12 months of adjunct carvedilol treatment. For assessment of antioxidative enzyme activity, a control group comprised 29 age-matched healthy children.

RESULTS

Twenty-one children (12 boys, 9 girls; age range, 7 months to 16 years; 100% white) completed the study. Four patients discontinued carvedilol at the beginning of the study due to severe arrhythmia which required amiodarone therapy (2 patients), bradycardia and hypotension (1), and bronchospasm (1). Carvedilol (0.4 mg/kg/d in children <or=62.5 kg or 25 mg/d in children >62.5 kg) was associated with significant decreases from baseline in systolic BP (130 [4] vs 123 [3] mm Hg; P<0.05), diastolic BP (85 [4] vs 77 [4] mm Hg; P<0.05), and HR (81 [4] vs 65 [4] bpm; P<0.001) after the first month of addition to standard therapy. At 6 months, there were significant improvements from baseline in EF (37.2% [2.4%] vs 50.2% [2.3%]; P<0.001) and FS (18.37% [2.00%] vs 23.58% [0.90%]; P<0.001). Modified NYHAC class was significantly improved in 80% of children (2.9 vs 2.3; P<0.001) at 12 months. The highest dose of carvedilol (0.8 mg/kg/d in children <or=62.5 kg or 50 mg/d in children >62.5 kg) was well tolerated in all 21 children. No serious AEs that necessitated study drug discontinuation (tiredness, headache, vomiting) were observed. At baseline, mean (SE) erythrocyte SOD activity (2781 [116] vs 2406 [102] U/g Hb; P<0.05) and GR activity (5.3 [0.3] vs 3.0 [0.2] micromol nicotinamide adenine dinucleotide phosphate [NADPH]/min/g Hb; P<0.001) were significantly higher in children with DCM who received standard therapy compared with healthy controls.CAT activity (12.7[0.9] vs 18.5 [1.0]U/g Hb; P<0.001) was significantly lower, while GSH-Px was unchanged. At 6 and 12 months of therapy, carvedilol plus standard treatment was associated with significant decreases from baseline in SOD (2516 [126] and 2550 [118], respectively, vs 2781 [116] U/g Hb; both, P<0.001) and GR (4.7 [0.3] and 4.1 [0.2], respectively, vs 5.3 [0.2] micromol NADPH/min/g Hb; P<0.05 and P<0.001) and increased CAT (16.9 [1.0] and 16.4 [0.7], respectively, vs 12.7 [0.9] U/g Hb; both, P<0.001).

CONCLUSIONS

These pediatric patients with DCM treated for 12 months with carvedilol (up to 0.8 mg/kg/d in children <or=62.5 kg or 50 mg/d in children >62.5 kg) were found to have significant improvements in LVF and symptoms of HF. Twelve months of carvedilol therapy was associated with antioxidant enzyme activities near those observed in healthy children.

Alveolar gas diffusion abnormalities in heart failure

In heart failure (HF), development of pressure or volume overload of the lung microcirculation elicits a series of structural adaptations, whose functional correlate is an increased resistance to gas transfer across the alveolar-capillary membrane. Acutely, hydrostatic mechanical injury causes endothelial and alveolar cell breaks, impairment of the cellular pathways involved in fluid filtration and reabsorption, and resistance to gas transfer. This process, which is reminiscent of the so-called alveolar-capillary stress failure, is generally reversible. When the alveolar membrane is chronically challenged, tissue alterations are sustained and a typical remodeling process may take place that is characterized by fixed extracellular matrix collagen proliferation and reexpression of fetal genes. Remodeling leads to a persistent reduction in alveolar-capillary membrane conductance and lung diffusion capacity. Changes in gas transfer not only reflect the underlying lung tissue damage but also bring independent prognostic information and may play a role in the pathogenesis of exercise limitation and ventilatory abnormalities. They are not responsive to fluid withdrawal by ultrafiltration and tend to be refractory even to heart transplantation. Some drugs can be effective that modulate lung remodeling (eg, angiotensin-converting enzyme inhibitors, whose impact on the natural course of cardiac remodeling is well known) or that increase nitric oxide availability and nitric oxide-mediated pulmonary vasodilation (eg, type 5 phosphodiesterase inhibitors). This review focuses on the current knowledge of these topics.

Analysis of randomized controlled trials on the effect of magnitude of heart rate reduction on clinical outcomes in patients with systolic chronic heart failure receiving beta-blockers

Beta blockers improve cardiac function and prolong survival in patients with systolic chronic heart failure (CHF). However, the exact mechanisms underlying these benefits are uncertain. Specifically, it is unclear whether a close relation exists between heart rate (HR) reduction and clinical outcomes with these agents. This hypothesis was therefore tested within randomized controlled trials of beta blockers in systolic CHF. Left ventricular ejection fraction (LVEF) and HR values at baseline and study end were obtained from available beta-blocker randomized clinical trials. The relation between change in HR and all-cause mortality as well as the LVEF was determined using regression analysis. Thirty-five trials, which included 22,926 patients with a mean follow-up duration of 9.6 months, were analyzed for all-cause mortality, the LVEF, and HR. There was a close relation between all-cause annualized mortality rate and HR (adjusted R2 = 0.51, p = 0.004). A strong correlation between change in HR and change in LVEF (adjusted R2 = 0.48, p = 0.000) was also observed. When only trials with >100 patients were included, an even tighter correlation was seen (adjusted R2 = 0.60, p = 0.0004). In conclusion, these analyses indicate that a major contributor to the clinical benefits of beta-blocker therapy in systolic CHF may be the HR-lowering effect of these agents. Therefore, the magnitude of HR reduction may be more important than the achievement of target dose in beta-blocker treatment of systolic CHF.

Pulmonary function at peak exercise in patients with chronic heart failure

BACKGROUND

Various respiratory abnormalities are associated with chronic heart failure (CHF). However, changes in inspiratory capacity (IC) and breathing pattern from rest to exercise in patients with CHF have not been thoroughly investigated in these patients.

MATERIALS AND METHODS

Seventy seven (66 male/11 female) patients with clinical stable CHF (age: 52+/-11 years) were studied. All the patients underwent pulmonary function tests, including measurements of IC and maximal inspiratory pressure (Pimax) at rest and then a maximal cardiopulmonary exercise testing (CPET) on a treadmill. During the CPET, IC was measured every 2 min. Pimax was measured again after the end of CPET.

RESULTS

Percent predicted forced expiratory volume in 1 s (FEV1) was 91+/-12, %predicted forced vital capacity (FVC) was 92+/-13, %FEV1/FVC was 81+/-4, and %predicted IC was 85+/-18. Peak exercise IC was lower than resting (2.4+/-0.6 vs. 2.6+/-0.6 l, p<0.001). Analysis of variance between Weber's groups revealed statistically significant differences in peak exercise IC (p<0.001), VE/VCO2slope (p<0.001), resting Pimax (p=0.005) and post-exercise Pimax (p<0.001). At rest, there was a statistically significant difference in end-tidal CO2 (P(ETCO2)) (p=0.002), in breathing frequency (p=0.004), in inspiratory time (Ti) (p=0.04) and in total respiratory time (T(Tot)) (p=0.004) among Weber's groups. At peak exercise there was a statistically significant decrease in minute ventilation (VE) (p<0.001), tidal volume (VT) (p<0.001), respiratory cycle (VT/TI) (p<0.001) and P(ETCO2) (p<0.001). Peak IC was correlated with peak VO2 (r=0.72, p<0.001), anaerobic threshold (r=0.71, p<0.001), VO2/t slope (r=0.54, p<0.0001), and post-exercise Pimax (r=0.62, p<0.001).

CONCLUSIONS

In patients with CHF, peak exercise IC is reduced in parallel with disease severity, which is probably due to respiratory muscle dysfunction.

Theoretical rationale and practical recommendations for cardiopulmonary exercise testing in patients with chronic heart failure

The syndrome of chronic heart failure (CHF) becomes increasingly prevalent in older patients, and while mortality rates are declining in most cardiovascular diseases, both prevalence and mortality in CHF remain high. The heart is unable to meet the demands of the skeletal musculature, and symptoms manifest as dyspnoea and signs of fatigue during exercise. The cardiopulmonary exercise test (CPET) can provoke symptoms which may be useful in improving the accuracy of diagnosis in CHF in a non-invasive setting. CPET also provides important information on the pathophysiology of exercise limitation, risk stratification and can establish exercise-training protocols. The information provided by the CPET allows suitable pharmacological or device-based adjustments to be considered in the management of CHF, which can be crucial in maintaining a patient's quality of life. This manuscript provides a useful insight into the theoretical rationale and practical recommendations for CPET in patients with CHF. Prior to CPET, it is important to consider the mode of exercise, as cycle ergometry or treadmill protocols will yield different outcomes in patients with CHF. We discuss how pre-CPET set-up procedures should be conducted and also the significance of electrocardiographic abnormalities found in CHF patients, and how these should be interpreted. The assessment of lung function is integral to the underlying pathophysiological basis of exercise limitation and we explain how this should be performed. CHF patients display the following abnormal exercise responses which can be identified by CPET: peak oxygen uptake ( [Formula: see text] peak), anaerobic threshold (AT), DeltaVO(2)/Delta work rate (WR), peak oxygen pulse, estimated peak stroke volume and predicted peak heart rate are reduced. The [Formula: see text] slope is abnormally high and the breathing reserve is normal or high. An immediate post-exercise increase in O(2) pulse is evident, and/or a regular oscillatory breathing pattern has been observed at lower exercise intensities in some CHF patients. Symptoms of breathlessness, fatigue, and/or leg pain occur earlier during CPET and may cause the CPET to be aborted early. We explain the significance of the 9-panelled array, and how it can help to determine the underlying pathophysiology of exercise intolerance in these patients.

Carvedilol reduces exercise-induced hyperventilation: A benefit in normoxia and a problem with hypoxia

AIMS

To evaluate whether carvedilol influences exercise hyperventilation and the ventilatory response to hypoxia in heart failure (HF).

METHODS AND RESULTS

Fifteen HF patients participated to this double blind, randomised, placebo controlled, cross-over study. Patients were evaluated by quality of life questionnaire, echocardiography, pulmonary function and cardiopulmonary exercise tests (ramp and constant workload) both in normoxia (FiO2 = 21%) and hypoxia (FiO2 = 16%, equivalent to a simulated altitude of 2000 m). Carvedilol improved clinical condition and reduced left ventricle size, but had no effect on lung mechanics. In normoxia during exercise, ventilation was lower, V(CO2) unchanged and PaCO2 (constant workload) or PetCO2 (ramp) higher with carvedilol, exercise capacity was unchanged (peak workload 92+/-22 and 90+/-22W for placebo and carvedilol, respectively). Abnormal V(E)/V(CO2) slope was reduced by carvedilol. Hypoxia increased ventilation but less with carvedilol; exercise capacity decreased to 87+/-21W (placebo) and to 80+/-11 W (carvedilol, p < 0.01). With hypoxia, carvedilol decreased V(E)/V(CO2) slope. At constant workload exercise with hypoxia, PaO2 decreased to 69+/-6 mm Hg (placebo) and to 64+/-5 (carvedilol, p < 0.01).

CONCLUSION

Carvedilol reduced hyperventilation possibly by reducing peripheral chemoreflex sensitivity as suggested by PaCO2 increase with normoxia and PaO2 decrease with hypoxia without V(CO2) and V(D)/V(T) changes. Lessening hyperventilation is beneficial when breathing normally, but detrimental when hyperventilation is needed for exercise at high altitude.

Effects of continuous positive airway pressure on pulmonary function and exercise tolerance in patients with congestive heart failure

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP) has been used to improve cardiopulmonary function and reduce pulmonary edema symptoms in patients with congestive heart failure (CHF). The objective of this study was to evaluate the efficacy of CPAP therapy on pulmonary function and exercise tolerance in patients with CHF.

DESIGN

Prospective blind randomized clinical study.

PARTICIPANTS

Twenty-four patients with class II or III CHF and dilated cardiomyopathy were randomly assigned to 30 min of CPAP therapy and respiratory exercises (CPAP group) or respiratory exercise only (control group) once a day for 14 days.

MEASUREMENTS AND RESULTS

Evaluation of pulmonary function was performed measuring FEV1 and FVC. Exercise tolerance was assessed measuring the distance walked during the 6-min walking test (6MWT). These parameters were measured before treatment and 4 days, 9 days, and 14 days later. CPAP therapy caused a progressive increase (p < 0.05) in both FVC (maximum of 16% after 9 days) and FEV1 (maximum of 14% after 14 days) compared to basal values, without significant changes in the control group. The 6MWT showed a progressive improvement in the distance walked in the CPAP group, reaching approximately 28% above the basal values in the CPAP group and without significant changes in the control group.

CONCLUSIONS

These data show that the use of CPAP therapy for 2 weeks on a daily basis is able to enhance pulmonary function and consequently improve the tolerance to physical activities in patients with CHF. The clinical implication of this finding is that CPAP therapy could potentially be used as an adjunct to the treatment of CHF patients.

VE/VCO2 slope is associated with abnormal resting haemodynamics and is a predictor of long-term survival in chronic heart failure

BACKGROUND

Patients with chronic heart failure (CHF) present with exercise-induced hyperpnea, but its pathophysiological mechanism has not been thoroughly investigated. We aimed to determine the relationship between exercise-induced hyperpnea, resting haemodynamic measurements and the validity of ventilatory response (V(E)/V(CO(2)) slope) as a mortality predictor in CHF patients.

METHODS

Ninety-eight CHF patients (90M/8F) underwent a symptom-limited treadmill cardiopulmonary exercise test (CPET). Right heart catheterization and radionuclide ventriculography were performed within 72 h of CPET.

RESULTS

Twenty-seven patients died from cardiac causes during 20+/-6 months follow-up. Non-survivors had a lower peak oxygen consumption (V(O(2)p)), (16.5+/-4.9 vs. 20.2+/-6.1, ml/kg/min, p=0.003), a steeper V(E)/V(CO(2)) slope (34.8+/-8.3 vs. 28.9+/-4.8, p<0.001) and a higher pulmonary capillary wedge pressure (PCWP) (19.5+/-8.6 vs. 11.7+/-6.5 mm Hg, p=0.008) than survivors. By multivariate survival analysis, the V(E)/V(CO(2)) slope as a continuous variable was an independent prognostic factor (chi(2): 8.5, relative risk: 1.1, 95% CI: 1.03-1.18, p=0.004). Overall mortality was 52% in patients with V(E)/V(CO(2)) slope > or =34 and 18% in those with V(E)/V(CO(2)) slope <34 (log rank: 18.5, p<0.001). In a subgroup of patients (V(O(2)p): 10-18 ml/kg/min), V(E)/V(CO(2)) slope was a significant predictor of mortality (relative risk: 6.2, 95% CI: 1.7-22.2, p=0.002). Patients with high V(E)/V(CO(2)) slope had higher resting PCWP (19.9+/-9.1 vs. 11.3+/-5.7 mmHg, p<0.001) and V(E)/V(CO(2)) slope correlated significantly with PCWP (r: 0.57, p<0.001).

CONCLUSIONS

The V(E)/V(CO(2)) slope, as an index of ventilatory response to exercise, improves the risk stratification of CHF patients. Interstitial pulmonary oedema may be a pathophysiological mechanism of inefficient ventilation during exercise in these patients.

Effects of beta-blocker therapy on ventilatory responses to exercise in patients with heart failure

BACKGROUND

Ventilatory efficiency is the increase in ventilation relative to carbon dioxide production during exercise. Congestive heart failure (CHF) is associated with decreased ventilatory efficiency. beta-blockers improve hemodynamics, prolong survival, and improve functional class in patients with CHF, though peak exercise performance may not improve. We hypothesized beta-blockers increase ventilatory efficiency in patients with CHF.

METHODS AND RESULTS

The study group comprised 614 subjects with left ventricular ejection fraction < or = 40% referred for cardiopulmonary exercise testing. Clinical and exercise data were reviewed and recorded. For comparison, subjects were divided into those treated with beta-blockers (n = 195) and those not treated (n = 419). Subjects on beta-blockers had lower minute ventilation (12 +/- 4 versus 14 +/- 4 L/min, P < .001) at rest, which remained lower during submaximal and maximal exercise, by 4 and 6 L/min, respectively (P = .001). Ventilatory efficiency was increased in subjects treated with beta-blockers at submaximal (32 +/- 6 versus 34 +/- 7, P = .002) and maximal (34 +/- 7 versus 37 +/- 10, P = .005) exercise. Differences between treatment subgroups remained significant by covariate analysis; beta-blockers were also independently associated with decreased minute ventilation by multiple regression.

CONCLUSION

Beta-blockers may be associated with increased ventilatory efficiency in CHF patients, which may contribute to improved functional class and quality of life.

The effects of long-term beta-blockade on the ventilatory responses to exercise in chronic heart failure

AIMS

Chronic heart failure (CHF) patients complain of breathlessness and fatigue. Beta-blockers improve symptoms, echocardiograpahic variables and prognosis in CHF, but their effect on exercise capacity remains unclear. The aim of this study was to describe the effects of long-term beta-blocker therapy on metabolic gas exchange variables and ventilation during exercise in CHF patients.

METHODS

42 patients with symptomatic heart failure due to left ventricular systolic dysfunction (ejection fraction 33.2 (8.2)) on loop diuretics and angiotensin-converting enzyme inhibitors or angiotensin II antagonists, underwent exercise testing with metabolic gas exchange. They were then initiated onto and uptitrated to the maximum tolerated dose of beta-blockers. After 1 year of follow-up, patients were invited back for repeat testing.

RESULTS

35 patients attended for repeat exercise testing. Four patients had died, and three had not tolerated beta-blockade. After 1 year, exercise time was increased (487 (221) vs. 500 (217), p<0.05), and peak oxygen consumption and V(E)/V(CO(2)) slope were unchanged (20.9 (5.0) vs. 20.0 (5.4), p=0.15 and 36.7 (8.3) vs. 37.3 (7.8), p=0.70). Peak ventilation, (61.5 (12.9) vs. 57.1 (13.4), p<0.05), peak carbon dioxide production (1629 (404) vs. 1496 (375), p<0.02) and hence respiratory exchange ratio (1.02 (0.08) vs. 0.98 (0.06) p<0.02) and p<0.05) were reduced. Submaximal oxygen consumption and carbon dioxide production were lower at matched workloads. The slope relating symptoms to ventilation (Borg/V(E) slope) was less steep following beta-blockade (0.18 (0.09) vs. 0.15 (0.06), p<0.05).

CONCLUSION

Long term beta-blocker therapy increases exercise time but not peak oxygen consumption, and reduces peak carbon dioxide production. CHF patients are less symptomatic for a given ventilation during exercise following beta-blocker treatment.

Impact of medical treatment on lung diffusion capacity in elderly patients with heart failure. Baseline characteristics and 1-year follow up after medical treatment

AIM

The aim of this investigation was (1) to study the effect of untreated chronic heart failure (CHF) on alveolar membrane diffusion capacity (transfer coefficient, K(CO)) in elderly patients and (2) to study the impact of the standard regime of medical treatment with diuretics and ACE-inhibitor/angiotensin-II receptor antagonists on K(CO) in these patients.

METHODS

Non-medicated patients (except for diuretics) with symptoms of heart failure (NYHA II-III) and echocardiographically estimated left ventricular ejection fraction (LVEF) <0.40 were recruited. All were characterized according to the results of multiple ECG-gated radionuclide ventriculography (MUGA). LVEF<0.50 when measured by MUGA was considered as heart failure (HF). A total of 20 patients fulfilled the criteria. All patients had a lung function test including measurement of K(CO) and a MUGA for LVEF measurement performed prior to medical treatment (baseline) and after 1 year of treatment with diuretics and ACE-inhibitors/angiotensin-II receptor antagonists. Age- and gender-matched healthy volunteers were included as control group.

RESULTS

(mean+/-S.E.M.): K(CO) at baseline was 0.95+/-0.06 and 1.25+/-0.04 mmol/min x kPa/l in HF patients and controls, respectively (p<0.05). After 1 year of treatment, K(CO) was normalized in the HF group (1.23+/-0.13 mmol/s x kPa, p<0.05). LVEF increased in the HF group from 0.28+/-0.03 at baseline to 0.34+/-0.03 after 1 year of treatment (p<0.05).

CONCLUSION

Elderly patients with symptomatic HF (NYHA II-III) and reduced systolic function have respiratory dysfunction in the form of reduced K(CO). One year of medical treatment had a significant beneficial effect on K(CO) and LVEF.

Exercise-induced changes in exhaled nitric oxide in heart failure

BACKGROUND

In heart failure abnormalities of pulmonary function are frequently observed as shown by hyperpnea, reduced lung compliance, reduced alveolar-capillary gas diffusion, positive methacholine challenge and, during exercise, early expiratory flow limitation. Nitric oxide (NO) might be related to all the above abnormalities.

AIMS

We evaluated whether a correlation between exhaled NO (eNO) and lung function exists at rest and during exercise in heart failure.

METHODS

We studied 33 chronic heart failure patients and 11 healthy subjects with: (a) standard pulmonary function, (b) lung diffusion for carbon monoxide (DLco) including its subcomponents, capillary volume and membrane resistance and eNO both at rest and during light exercise, (c) maximal cycloergometer cardiopulmonary exercise test.

RESULTS

Forced expiratory volume in 1 s (FEV(1)) was reduced in heart failure patients (83+/-17% of predicted), as was DLco (75+/-18% of predicted) due to reduced membrane resistance (32.6+/-10.3 ml mmHg(-1) min(-1) vs. 39.9+/-6.9 in patients vs. controls, P<0.02). Exhaled NO was lower in patients vs. controls (9.7+/-5.4 ppm vs. 14.4+/-6.4, P<0.05) and was, during exercise, constant in patients and reduced in controls. No significant correlation was found between eNO and lung function. Vice-versa eNO changes during exercise were correlated with peak exercise oxygen consumption (r=0.560, P<0.001).

CONCLUSIONS

The hypothesis of a link between eNO and lung function in heart failure was not proved. The correlation between eNO changes during exercise and peak V(O(2)) might be due to hemoglobin oxygenation, which binds NO to hemoglobin.

Therapeutic Update: Non-Selective Beta- and Alpha-Adrenergic Blockade in Patients With Coexistent Chronic Obstructive Pulmonary Disease and Chronic Heart Failure

Patients with chronic heart failure (CHF) have a resting restrictive ventilatory defect. Any type of exercise requires patients with CHF to markedly increase their minute ventilation. Patients with chronic obstructive pulmonary disease (COPD) have airflow obstruction that leads to dynamic lung hyperinflation and reduced ventilatory response to exercise. Because exercise is associated with abnormally high minute ventilation in patients with CHF and with a limited minute ventilation increase in patients with COPD, functional capacity is severely impaired in patients with coexistent CHF and COPD. Optimal treatment of both conditions is a prerequisite to maximally improve functional capacity in patients with CHF and COPD. Unfortunately, beta-adrenergic blockade, the current cornerstone of CHF therapy, is frequently omitted in patients with CHF and COPD for fear of inducing bronchoconstriction. Furthermore, when prescribed, beta-adrenergic blockade is often attempted with a moderate dose of metoprolol tartrate, a beta-1-blocker that results in lesser clinical benefits than combined non-selective beta-blockade with carvedilol at the maximally recommended dose. Recent experience indicates that combined non-selective beta- and alpha-blockade with carvedilol is well tolerated in patients with COPD who do not have reversible airway obstruction. Alpha-adrenergic blockade may promote mild bronchodilation that offsets non-selective beta blockade-induced bronchoconstriction in patients with obstructive airway disease.

Effects of carvedilol on left ventricular remodelling in chronic stable heart failure: a cardiovascular magnetic resonance study

BACKGROUND

The ability of beta blockers to improve left ventricular function has been demonstrated, but data on the effects on cardiac remodelling are limited.

OBJECTIVE

To investigate, using cardiovascular magnetic resonance (CMR), the effects of carvedilol on left ventricular remodelling in patients with chronic stable heart failure and left ventricular systolic dysfunction caused by coronary artery disease.

DESIGN

Randomised, double blind, placebo controlled study.

SETTING

Chronic stable heart failure.

PATIENTS AND INTERVENTION

34 patients with chronic stable heart failure and left ventricular systolic function taking part in the CHRISTMAS trial (double blind carvedilol v placebo) underwent CMR before randomisation and after six months of treatment.

MAIN OUTCOME MEASURE

Left ventricular remodelling at six months.

RESULTS

The carvedilol and placebo groups were well balanced at baseline, with no significant intergroup differences. Over the study period, there was a significant reduction in end systolic volume index (ESV(I)) and end diastolic volume index (EDV(I)) between the carvedilol and the placebo group (carvedilol -9 v placebo +3 ml/m2, p = 0.0004; carvedilol -8 v placebo 0 ml/m2, p = 0.05). The ejection fraction increased significantly between the groups (carvedilol +3% v placebo -2%, p = 0.003).

CONCLUSIONS

Treatment of chronic stable heart failure with carvedilol results in significant improvement in left ventricular volumes and function. These effects might contribute to the benefits of carvedilol on mortality and morbidity in patients with chronic heart failure.

Carvedilol: a review of its use in chronic heart failure

Carvedilol (Dilatrend) blocks beta(1)-, beta(2)- and alpha(1)-adrenoceptors, and has antioxidant and antiproliferative effects. Carvedilol improved left ventricular ejection fraction (LVEF) in patients with chronic heart failure (CHF) in numerous studies. Moreover, significantly greater increases from baseline in LVEF were seen with carvedilol than with metoprolol in a double-blind, randomised study and in a meta-analysis. Carvedilol also reversed or attenuated left ventricular remodelling in patients with CHF and in those with left ventricular dysfunction after acute myocardial infarction (MI). Combined analysis of studies in the US Carvedilol Heart Failure Trials Program (patients had varying severities of CHF; n = 1094) revealed that mortality was significantly lower in carvedilol than in placebo recipients. In addition, the risk of hospitalisation for any cardiovascular cause was significantly lower with carvedilol than with placebo. Mortality was significantly lower with carvedilol than with metoprolol in patients with mild to severe CHF in the Carvedilol Or Metoprolol European Trial (COMET) [n = 3029]. The Carvedilol Prospective Randomised Cumulative Survival (COPERNICUS) trial (n = 2289) demonstrated that compared with placebo, carvedilol was associated with significant reductions in all-cause mortality and the combined endpoint of death or hospitalisation for any reason in severe CHF. All-cause mortality was reduced in patients who received carvedilol in addition to conventional therapy compared with those who received placebo plus conventional therapy in the Carvedilol Post-Infarct Survival Control in LV Dysfunction (CAPRICORN) trial (enrolling 1959 patients with left ventricular dysfunction following acute MI). Carvedilol was generally well tolerated in patients with CHF. Adverse events associated with the alpha- and beta-blocking effects of the drug occurred more commonly with carvedilol than with placebo, whereas placebo recipients were more likely to experience worsening heart failure. In conclusion, carvedilol blocks beta(1)-, beta(2)- and alpha(1)-adrenoceptors and has a unique pharmacological profile. It is thought that additional properties of carvedilol (e.g. antioxidant and antiproliferative effects) contribute to its beneficial effects in CHF. Carvedilol improves ventricular function and reduces mortality and morbidity in patients with mild to severe CHF, and should be considered a standard treatment option in this setting. Administering carvedilol in addition to conventional therapy reduces mortality and attenuates myocardial remodelling in patients with left ventricular dysfunction following acute MI. Moreover, mortality was significantly lower with carvedilol than with metoprolol in patients with mild to severe CHF, suggesting that carvedilol may be the preferred beta-blocker.

Alveolar-capillary membrane dysfunction in heart failure: evidence of a pathophysiologic role

Chronic heart failure (CHF) increases the resistance to gas transfer across the alveolar-capillary interface. Recent reports highlight the pathophysiologic relevance of changes in the lung leading to impaired fluid and gas exchange in the distal airway spaces. Under experimental conditions, an acute pressure or volume overload can injure the alveolar blood-gas barrier. This may disrupt its anatomic configuration, cause the loss of regulation of fluid-flux, and thereby affect alveolar gas conductance properties. These ultrastructural changes have been identified under the term of stress failure of the alveolar-capillary membrane. In the short term, these alterations are reversible due to the reparative properties of the alveolar surface. However, when the alveolar-capillary membrane is chronically challenged, for instance in patients with CHF, by noxious stimuli, such as humoral, cytotoxic, and genetic factors other than by mechanical trauma, remodeling of pathophysiologic and clinical importance may take place. These changes in some respects resemble the remodeling process in the heart. Emerging findings support the view that, in patients with CHF, alveolar-capillary membrane dysfunction may contribute to symptom exacerbation and exercise intolerance, and may be an independent prognosticator of clinical course. Angiotensin-converting enzyme inhibitors ameliorate the alveolar membrane gas conductance abnormality, reflecting improvement in the remodeling process. This article reviews the putative mechanisms involved in the impairment in gas diffusion in CHF patients and provides a link between physiologic changes and clinical findings.

Resting lung function and hemodynamic parameters as predictors of exercise capacity in patients with chronic heart failure

STUDY OBJECTIVES

The aim of this study was to examine the role of resting pulmonary function and hemodynamic parameters as predictors of exercise capacity in patients with chronic heart failure.

MEASUREMENTS AND RESULTS

Fifty-one patients with chronic heart failure underwent resting pulmonary function testing, including inspiratory capacity (IC) and symptom-limited, treadmill cardiopulmonary exercise testing (CPET). Right-heart catheterization and radionuclide ventriculography were performed within 2 days of CPET. Mean (+/- SD) left ventricular ejection fraction was 31 +/- 12% and cardiac index was 2.34 +/- 0.77 L/min/m(2). Percentage of predicted FEV(1) was 92 +/- 14%, percentage of predicted FVC was 94 +/- 15%, FEV(1)/FVC was 81 +/- 4%, and percentage of predicted IC was 84 +/- 18%. Mean peak oxygen uptake (peak O(2)) was 17.9 +/- 5.4 mL/kg/min. Analysis of variance among the three functional Weber classes showed statistically significant differences for pulmonary capillary wedge pressure (PCWP) and IC. Specifically, the more severe the exercise intolerance, the lower was IC and the higher was PCWP. In a multivariate stepwise regression analysis, using peak O(2) (liters per minute) as the dependent variable and the pulmonary function test measurements as independent variables, the only significant predictor selected was IC (r = 0.71, p < 0.0001). In a final stepwise regression analysis including all the independent variables of the resting pulmonary function tests and hemodynamic measurements, the two predictors selected were IC and PCWP (r(2) = 0.58).

CONCLUSIONS

In patients with chronic heart failure, IC is inversely related to PCWP and is a strong independent predictor of functional capacity.