Endotoxin and immune activation in chronic heart failure: a prospective cohort study

BACKGROUND

Immune activation in patients with chronic heart failure may be secondary to endotoxin (lipopolysaccharide) action. We investigated the hypothesis that altered gut permeability with bacterial translocation and endotoxaemia would be increased in patients with oedema secondary to congestive heart failure.

METHODS

We compared 20 patients who had chronic heart failure with recent-onset peripheral oedema (mean age 64 years [SD 10], New York Heart Association [NYHA] class 3.3 [0.7]), 20 stable non-oedematous patients with chronic heart failure (mean age 63 years [19], NYHA class 2.6 [0.7]), and 14 healthy volunteers (mean age 55 years [16]). Biochemical markers of endotoxaemia, inflammation, and immune activation were measured. Ten patients were studied within 1 week of complete resolution of oedema. Five patients survived longer than 6 months and were restudied again after remaining free of oedema for more than 3 months.

FINDINGS

Mean endotoxin concentrations were higher in oedematous patients with chronic heart failure than in stable patients with chronic heart failure (0.74 [SD 0.45] vs 0.37 EU/mL [0.23], p=0.0009) and controls (0.46 EU/mL [0.21], p=0.02). Oedematous patients had the highest concentrations of several cytokines. After short-term diuretic treatment, endotoxin concentrations decreased from 0.84 EU/mL [0.49] to 0.45 EU/mL [0.21], p<0.05) but cytokines remained raised. After freedom of oedema for more than 3 months after oedema resolved, endotoxin concentrations remained unchanged from the previous visit (0.49 EU/mL [0.06], p=0.45).

INTERPRETATION

Raised concentrations of endotoxin and cytokines are found in patients with chronic heart failure during acute oedematous exacerbation. Intensified diuretic treatment can normalise endotoxin concentrations. Our preliminary findings suggest that endotoxin may trigger immune activation in patients with chronic heart failure during oedematous episodes.

Cytokines and neurohormones relating to body composition alterations in the wasting syndrome of chronic heart failure

BACKGROUND

Chronic heart failure is one of a number of disorders associated with the development of a wasting syndrome. The precise mechanisms of this remain unknown, but previous studies have suggested a role for immune and neurohormonal factors.

METHODS

We aimed to investigate in detail the differences in body composition (dual X-ray absorptiometry) and the relationship to candidate biochemical factors of the immune, neurohormonal and metabolic systems in 15 healthy controls, 36 stable non-cachectic and 18 cachectic patients with chronic heart failure.

RESULTS

Non-cachectic patients showed reduced leg lean tissue (-9.1%, P<0.01) compared to controls. Cachectic patients had significantly reduced lean (-21.0% vs controls, -19.9% vs non-cachectics), fat (-33.0% vs controls, -37. 0% vs non-cachectics) and bone tissue (-17.5% vs controls, -15.9% vs non-cachectics) (all P<0.0001). Cachectic patients showed a significantly increased cortisol/dehydroepiandrosterone ratio (+203% vs controls, P<0.0001; +89% vs non-cachectics, P=0.0011) and increased cytokine levels (TNF-alpha, soluble TNF-receptor 1, interleukin-6). The levels of catabolic hormones and cytokines correlated significantly with reduced muscle and fat tissue content and reduced bone mass.

CONCLUSION

Peripheral loss of muscle tissue is a general finding in chronic heart failure. The wasting in cardiac cachexia affects all tissue compartments and is significantly related to neurohormonal and immunological abnormalities.

Baseline clinical characteristics of patients recruited into the assessment of treatment with lisinopril and survival study

BACKGROUND

The beneficial effect of ACE inhibitors on mortality has been established in a series of trials. However, in clinical practice, ACE inhibitors are commonly administered in doses much lower than those shown to be effective in the landmark trials.

AIMS

This report describes the baseline characteristics of the patients recruited into the ATLAS study by age and gender sub-groups.

METHODS

The ATLAS study compared the effects of 'low' dose (2.5-5.0 mg/day) to 'high' dose (32.5-35.0 mg/day) lisinopril in a double-blind study of 3164 patients with moderate to severe heart failure and left ventricular ejection fraction < 30% during a mean follow-up period of 46 months. The primary end-point was all cause mortality and the principal secondary end-point a composite of all-cause hospitalisation or all-cause mortality.

RESULTS

Among patients with heart failure selected for the presence of left ventricular systolic function there were few differences among age groups or between genders. Older patients were not so heavy, were more likely to have ischaemic heart disease, hypertension and atrial fibrillation contributing to their heart failure and had a higher blood urea. Women were not so heavy as men. Age and gender had no major influence on mean ejection fraction or baseline treatment in the ATLAS study.

CONCLUSIONS

Weight and renal function may alter the plasma concentration of any given dose of an ACE inhibitor. Potential interactions between dose of lisinopril, weight and renal function will be explored after the study is completed.

Incidence and aetiology of heart failure; a population-based study

AIMS

To determine the incidence and aetiology of heart failure in the general population.

METHODS AND RESULTS

New cases of heart failure were identified from a population of 151 000 served by 82 general practitioners in Hillingdon, West London through surveillance of acute hospital admissions and through a rapid access clinic to which general practitioners referred all new cases of suspected heart failure. On the basis of clinical assessment, electrocardiography, chest radiography and transthoracic echocardiography, a panel of three cardiologists decided that 220 patients met the case definition of new heart failure over a 20 month period (crude incidence rate of 1.3 cases per 1000 population per year for those aged 25 years or over). The incidence rate increased from 0.02 cases per 1000 population per year in those aged 25-34 years to 11.6 in those aged 85 years and over. The incidence was higher in males than females (age-adjusted incidence ratio 1.75 [95% confidence interval 1.34-2.29, P<0.0001]). The median age at presentation was 76 years. The primary aetiologies were coronary heart disease (36%), unknown (34%), hypertension (14%), valve disease (7%), atrial fibrillation alone (5%), and other (5%).

CONCLUSIONS

Within the general population, new cases of heart failure largely occur in the elderly, and the incidence is higher in men than women. The single most common aetiology is coronary heart disease, but in a third of cases the aetiology cannot be determined on the basis of non-invasive investigation alone. To be relevant to clinical practice, future clinical trials in heart failure should not exclude the elderly.

An inhibitor of nitric oxide synthase does not increase contraction or beta-adrenoceptor sensitivity of ventricular myocytes from failing human heart

OBJECTIVE

Nitric oxide (NO) has been implicated in the depression of cardiac function in human heart failure. Some reports have identified iNOS (inducible nitric oxide synthase) within the myocyte component of the failing human heart, and NO is known to decrease the contraction amplitude of isolated ventricular myocytes. We have treated myocytes from failing human ventricle with a NOS inhibitor, NG-monomethyl-L-arginine (L-NMMA), in an attempt to restore contractile function.

METHODS AND RESULTS

Myocytes were isolated from failing and non-failing human ventricles and their contraction amplitude was measured during superfusion (32 degrees C, 1-2 mmol/l Ca2+) and electrical stimulation (0.1-2 Hz). The contraction amplitude of myocytes from failing hearts was depressed in a frequency-dependent manner. At 1 Hz, the contraction amplitude of cells from non-failing heart was 4.70 +/- 0.53% cell shortening (mean +/- SEM, n = 13 subjects), compared with 2.18 +/- 0.27% (P < 0.01, 11 patients) from patients with ischaemic heart disease (IHD) or 2.56 +/- 0.74% (P < 0.02, six patients) with dilated cardiomyopathy (DCM). Superfusion with 0.1 mmol/l L-NMMA did not increase contraction amplitude in myocytes from failing heart at either 0.2 Hz (n = 11) or 1 Hz (n = 7). Responses to beta-adrenoceptor stimulation were reduced in myocytes from failing human heart, with contraction amplitude in maximum isoprenaline 0.47 +/- 0.11 of that in high Ca2+ in the same cell (n = 6), compared to 0.99 +/- 0.07 in non-failing heart (n = 14, P < 0.01). The presence of 0.1 mmol/l L-NMMA did not increase the isoprenaline/Ca2+ ratio in myocytes from failing heart (0.40 +/- 0.09, P = NS).

CONCLUSION

These results do not suggest a functional role for tonic NO production in the frequency-dependent depression of contraction or beta-adrenoceptor desensitisation in myocytes from failing human ventricle.

Uric acid in chronic heart failure: a marker of chronic inflammation

BACKGROUND

Chronic heart failure is associated with hyperuricaemia and elevations in circulating markers of inflammation. Activation of xanthine oxidase, through free radical release, causes leukocyte and endothelial cell activation. Associations could therefore be expected between serum uric acid level, as a marker of increased xanthine oxidase activity, and markers of inflammation. We have explored these associations in patients with chronic heart failure, taking into account the hyperuricaemic effects of diuretic therapy and insulin resistance.

METHODS AND RESULTS

Circulating uric acid and markers of inflammation were measured in 39 male patients with chronic heart failure and 16 healthy controls. All patients underwent a metabolic assessment, which provided a measure of insulin sensitivity (intravenous glucose tolerance tests and minimal modelling analysis). Compared to controls, patients with chronic heart failure had significantly higher levels of circulating uric acid, interleukin-6, soluble tumour necrosis factor receptor (sTNFR)-1, soluble intercellular adhesion molecule-1 (ICAM-1, all P<0.001), E-selectin and sTNFR2 (both P<0.05). In patients with chronic heart failure, serum uric acid concentrations correlated with circulating levels of sTNFR1 (r=0.74), interleukin-6 (r=0.66), sTNFR2 (r=0.63), TNFa (r=0.60) (all P<0.001), and ICAM-1 (r=0.41, P<0.01). In stepwise regression analyses, serum uric acid emerged as the strongest predictor of ICAM-1, interleukin-6, TNF, sTNFR1 and sTNFR2, independent of diuretic dose, age, body mass index, alcohol intake, serum creatinine, plasma insulin and glucose, and insulin sensitivity.

CONCLUSIONS

Serum uric acid is strongly related to circulating markers of inflammation in patients with chronic heart failure. This is consistent with a role for increased xanthine oxidase activity in the inflammatory response in patients with chronic heart failure.

Mitochondrial DNA in idiopathic cardiomyopathy

AIMS

To investigate the frequency of pathogenic mitochondrial DNA mutations in idiopathic cardiomyopathy.

METHODS AND RESULTS

We investigated the occurrence of seven previously reported pathogenic mitochondrial DNA point mutations in 52 patients with idiopathic dilated cardiomyopathy (blood n=33, myocardium n=19), 10 patients with hypertrophic cardiomyopathy (blood n=7, myocardium n=3), 67 controls with ischaemic heart disease (blood n=53, myocardium n=14) and eight controls with no overt cardiac disease (blood n=4, myocardium n=4). Total DNA or cell lysates were studied by polymerase chain reaction amplification and restriction fragment length polymorphism analysis for the identification of the following mitochondrial DNA point mutations: A3243G, A3252G, A3260G, A4269G, A8344G, T8993G/C and T9997C. None of these point mutations were detected in the blood or myocardium of any of the individuals with dilated or hypertrophic cardiomyopathy or in the controls. In addition we investigated the occurrence of major deletions of mitochondrial DNA in eight patients with dilated cardiomyopathy (myocardium n=7, skeletal muscle n=1), three patients with ischaemic heart disease (myocardium n=3) and one control myocardium by Southern blot analysis. Deletions were not detected in any of the patients.

CONCLUSION

The results suggest that although these mutations are known to be associated with specific cardiomyopathies, they are not a common feature of idiopathic cardiomyopathy.

From overload to failure: what happens inside the myocyte

To determine whether there is a defect in the surviving muscle cells of the failing human heart, studies have been performed on individual myocytes isolated from normal and failing human myocardium. Myocytes from the failing ventricle contract and relax more slowly, and have a reduced contraction amplitude at physiological (but not low) stimulation frequencies. Slow relaxation is seen irrespective of the aetiology of the heart disease studied, and is more pronounced in myocytes from hypertrophied ventricles. Myocytes from hypertrophied ventricles are larger than normal, but the relaxation deficit is independent of cell size. Beta-adrenoceptor desensitization is evident in myocytes and it varies according to the severity of disease and with the age of the patient. Action potentials are longer in myocytes from failing human heart, probably because of an alteration in K+ current density. Many of the functional changes identified in failing human myocardium are seen at the level of the single cardiac myocyte, which implies that pharmacological or genetic manipulation of surviving cells is a logical therapeutic strategy.

Design and current status of ACTION: A Coronary disease Trial Investigating Outcome with Nifedipine GITS. Gastro-Intestinal Therapeutic System

AIMS

To present the design of ACTION (A Coronary disease Trial Investigating Outcome with Nifedipine GITS), an ongoing multicentre clinical outcome trial with nifedipine GITS (Gastro-Intestinal Therapeutic System) in patients with stable angina pectoris.

METHODS

At least 6000 patients with optimally treated stable angina without depressed left ventricular function are randomized in equal proportions to either nifedipine GITS or matching placebo (starting dose 30 mg, maintenance dose 60 mg once daily). Patients are followed for at least four years. The primary end-point, to be analyzed by assigned treatment, includes all-cause mortality, acute myocardial infarction, emergency coronary angiography for refractory angina, overt heart failure, debilitating stroke and peripheral revascularization. For this end-point, the trial has a power of 95% to detect a relative risk reduction of 18% at the 5%, level of significance, and is large enough to exclude an excess mortality caused by nifedipine GITS of 3.1 deaths per 1000 years of treatment or greater. The pre-specified early termination rule is more conservative in the case of a beneficial effect than in the case of an adverse effect of nifedipine GITS. The first patient was randomized on 29 November, 1996. By the end of April 1998, about 5200 patients had been started on study medication.

CONCLUSIONS

Results will be available in the autumn of 2003.

Deficient insulin-like growth factor I in chronic heart failure predicts altered body composition, anabolic deficiency, cytokine and neurohormonal activation

BACKGROUND

Recent studies of growth hormone supplementation in chronic heart failure have been associated with variable results. Acquired abnormalities of biochemical parameters of the growth hormone insulin-like growth factor I axis have been associated with severe chronic heart failure. There are suggestions of an acquired growth hormone resistance with deficient insulin-like growth factor I in some patients.

OBJECTIVES

Therefore, we set out to investigate the clinical and functional status and the degree of cytokine and neurohormonal alteration of chronic heart failure patients with deficient insulin-like growth factor I responses.

METHODS

Patients with chronic heart failure were divided into two groups according to their insulin-like growth factor I levels (classified according to the manufacturer's assay range in normal controls): low insulin-like growth factor I <104 (n = 20; 89 +/- 9.6 ng/ml), and normal/high >104 ng/ml (n = 32; 169 +/- 52 ng/ml). Between groups there was no difference in age (low versus high: 65.3 +/- 12.1 versus 61.6 +/- 9.1 years, p = 0.21), body mass index, aerobic capacity (peak oxygen consumption: low versus high: 15.5 +/- 5.2 versus 17.3 +/- 6.3 mL/kg/min, p = 0.23), left ventricular ejection fraction, New York Heart Association classification.

RESULTS

During quadriceps strength testing, patients with low insulin-like growth factor I had reduced absolute strength (-24%), and strength per unit area muscle (- 14%) than patients with normal/high insulin-like growth factor I. Leg muscle cross-sectional area was lower in the low insulin-like growth factor I group (-12% and -13% for right and left legs, respectively). These alterations were accompanied by increased levels of growth hormone (+145%), tumor necrosis factor-alpha (+46%), cortisol/ dehydroepiandrosterone ratio (+60%), noradrenaline (+49%) and adrenaline (+136%) (all at least p < 0.05).

CONCLUSIONS

Patients with low insulin-like growth factor I levels show signs of altered body composition, cytokine and neuroendocrine activation, to a greater extent than patients with normal/high levels.

Randomised, double-blind, placebo-controlled trial of human recombinant growth hormone in patients with chronic heart failure due to dilated cardiomyopathy

BACKGROUND

Some studies have suggested that treatment with recombinant human growth hormone (rhGH) increases left-ventricular mass and improves haemodynamic and functional status in patients with heart failure due to dilated cardiomyopathy. We did a double-blind, randomised, placebo-controlled study of rhGH in patients with chronic heart failure due to dilated cardiomyopathy.

METHODS

50 patients (43 men) were randomly allocated treatment with subcutaneous rhGH (2 IU daily) or placebo for a minimum of 12 weeks. The primary endpoints were the effects on left-ventricular mass and systolic wall stress. The secondary endpoints were the effects on left-ventricular size and function. Data were analysed by intention to treat.

FINDINGS

Patients in the rhGH group had an increase in left-ventricular mass compared with those in the placebo group (27%, p=0.0001). There was no significant difference in left-ventricular systolic wall stress, mean blood pressure, or systemic vascular resistance between the two groups. New York Heart Association functional class, left-ventricular ejection fraction, and distance on the 6 min walking test were unchanged. The change in serum insulin-like growth factor (IGF)-I concentrations (rhGH 77 ng/mL; placebo -19 ng/mL, GH vs placebo p=0.0001) was significantly related to the change in left-ventricular mass (r=0.55, p=0.0001). One patient in the rhGH group was withdrawn at 6 weeks because of worsening heart failure.

INTERPRETATION

There is a significant increase in left-ventricular mass in patients with dilated cardiomyopathy given rhGH but this is not accompanied by an improvement in clinical status. Changes in left-ventricular mass are related to changes in serum IGF-I concentrations. Whether a longer treatment period would provide clinical benefits and decrease mortality is unknown.

Regional differences in the characteristics and treatment of patients participating in an international heart failure trial. The Assessment of Treatment with Lisinopril and Survival (ATLAS) Trial Investigators

AIMS

This study was designed to determine regional differences in patient characteristics and medication use among patients entered into an international heart failure trial.

METHODS AND RESULTS

Data for this analysis were derived from the Assessment of Treatment with Lisinopril and Survival Study (ATLAS), a prospective randomized comparison of high- and low-dose therapy with lisinopril in patients with New York Heart Association class II, III, or IV chronic heart failure, which enrolled 3164 patients in 291 centers in 19 countries on 3 continents. Information was collected at baseline concerning patient demographics, etiology of heart failure, accompanying conditions, prior revascularization procedures, and medication use. The primary findings were a lower incidence of ischemic cardiomyopathy in southern and western Europe, more frequent diabetes in North America, and a greater use of coronary revascularization in the United States and Canada. There was substantial variation in medication use, particularly with regard to digoxin, anticoagulants, and amiodarone.

CONCLUSIONS

Although there is considerable overlap in guidelines concerning the treatment of heart failure issued by authorities in Europe and North America, there are significant regional variations in medication use. Some, but not all, of these differences can be explained by differences in patient characteristics.

Tumour necrosis factor alpha as a predictor of impaired peak leg blood flow in patients with chronic heart failure

Tumour necrosis factor alpha (TNF alpha) is increased in patients with cardiac cachexia, a condition associated with reduced peripheral blood flow both at rest and after interventions causing vasodilation. By contrast, in patients with chronic heart failure (CHF), higher TNF levels are associated with a greater capacity for vasodilation in the arm. To clarify the relationship between peripheral blood flow and TNF in CHF, we studied the relation between TNF alpha and blood flow in the leg (plethysmography, post maximal exercise and 5 min ischaemia) in 34 patients (age 63 +/- 2 years, ejection fraction 29 +/- 3%, peak VO2 16.6 +/- 1.1 ml/kg/min, mean +/- SEM). Peak leg blood flow correlated significantly with total TNF alpha (r = 0.68, p < 0.0001, peak VO2 (r = 0.54), and soluble TNF receptors 1 (r = 0.56) and 2 (r = 0.52, all p < 0.002). TNF alpha, soluble TNF receptors 1 and 2 and aldosterone correlated with peak blood flow independently of age, ejection fraction, peak VO2 and functional NYHA class. TNF alpha was the only parameter that showed strong correlations for peak blood flow in all clinically relevant subgroups (severe vs. mild, ischaemic vs. dilated, cachectic vs. non-cachectic patients). This study shows a close and inverse relationship between peak leg blood flow and the plasma concentration of TNF alpha, suggesting a pathophysiological role for TNF alpha in reducing peak peripheral blood flow in CHF.

Downregulation of immunodetectable connexin43 and decreased gap junction size in the pathogenesis of chronic hibernation in the human left ventricle

BACKGROUND

The regional wall motion impairment and predisposition to arrhythmias in human ventricular hibernation may plausibly result from abnormal intercellular propagation of the depolarizing wave front. This study investigated the hypothesis that altered patterns of expression of connexin43, the principal gap junctional protein responsible for passive conduction of the cardiac action potential, contribute to the pathogenesis of hibernation.

METHODS AND RESULTS

Patients with poor ventricular function and severe coronary artery disease underwent thallium scanning and MRI to predict regions of normally perfused, reversibly ischemic, or hibernating myocardium. Twenty-one patients went on to coronary artery bypass graft surgery, during which biopsies representative of each of the above classes were taken. Hibernation was confirmed by improvement in segmental wall motion at reassessment 6 months after surgery. Connexin43 was studied by quantitative immunoconfocal laser scanning microscopy and PC image software. Analysis of en face projection views of intercalated disks revealed a significant reduction in relative connexin43 content per unit area in reversibly ischemic (76.7+/-34.6%, P<.001) and hibernating (67.4+/-24.3%, P<.001) tissue compared with normal (100+/-30.3%); ANOVA P<.001. The hibernating regions were further characterized by loss of the larger gap junctions normally seen at the disk periphery, reflected by a significant reduction in mean junctional plaque size in the hibernating tissues (69.5+/-20.8%) compared with reversibly ischemic (87.4+/-31.2%, P=.012) and normal (100+/-31.5%, P<.001) segments; ANOVA P<.001.

CONCLUSIONS

These results indicate progressive reduction and disruption of connexin43 gap junctions in reversible ischemia and hibernation. Abnormal impulse propagation resulting from such changes may contribute to the electromechanical dysfunction associated with hibernation.

The role of cAMP in the frequency-dependent changes in contraction of guinea-pig cardiomyocytes

OBJECTIVES

beta-Receptor desensitisation, low basal cAMP, and a negative force-frequency relationship are characteristic changes in human heart failure. Isolated cardiomyocytes from noradrenaline-treated guinea pigs also show these features. We tested the hypothesis that low basal cAMP underlies the loss of contractile response to increasing stimulation frequency in this model.

METHODS

Isolated cardiomyocytes were obtained from noradrenaline-treated (NA) and sham-operated (SHAM) guinea pigs. They were stimulated from 0.1-2 Hz and contraction amplitude was monitored with a video edge-detection system.

RESULTS

NA cells had less positive amplitude-frequency responses (AFR) compared to SHAMs at 2 mM (P = 0.002, n = 17), or midrange Ca2+ concentrations (EC40-EC60) (P < 0.001, n = 13). When the cAMP agonist, 8-CPT-cAMP (CPT, 10 microM) or high Ca2+ (above EC75) was added to NA cells the AFR was normalised to that of SHAM myocytes (NA vs. SHAM P = ns). In control experiments the cAMP antagonists, Rp-cAMPS (Rpc) and Rp-8-CPT-cAMPS (Rp8, 100 microM), blocked the positive inotropic effects of CPT at 0.5 Hz (control pD2 = 4.36 +/- 0.06, Rp8 pD2 = 3.68 +/- 0.08, P < 0.0001), n = 6 paired). Rpc (100 microM) completely but reversibly blocked the effect of maximal isoprenaline in control experiments (P < 0.0001). Neither antagonist reduced the AFR compared to time-matched controls (P = ns, n = 6). Blockade of SERCA2a with thapsigargin resulted in a significant reduction in the AFR (ANOVA P < 0.0001).

CONCLUSIONS

The results are consistent with sarcoplasmic reticulum (SR) function being a more important determinant of the amplitude-frequency relationship than tonic levels of cAMP under basal conditions. Reversal of AFR depression by CPT may result from stimulation of SR Ca2+ uptake.

Skeletal muscle function and its relation to exercise tolerance in chronic heart failure

OBJECTIVES

This study sought to define the relation between muscle function and bulk in chronic heart failure (HF) and to explore the association between muscle function and bulk and exercise capacity.

BACKGROUND

Skeletal muscle abnormalities have been postulated as determinants of exercise capacity in chronic HF. Previously, muscle function in chronic HF has been evaluated in relatively small numbers of patients and with variable results, with little account being taken of the effects of muscle wasting.

METHODS

One hundred male patients with chronic HF and 31 healthy male control subjects were studied. They were matched for age (59.0 +/- 1.0 vs. 58.7 +/- 1.7 years [mean +/- SEM]) and body mass index (26.6 +/- 0.4 vs. 26.3 +/- 0.7 kg/m2). We assessed maximal treadmill oxygen consumption (VO2), quadriceps maximal isometric strength, fatigue (20-min protocol, expressed in baseline maximal strength) and computed tomographic cross-sectional area (CSA) at midthigh.

RESULTS

Peak VO2 was lower in patients (18.0 +/- 0.6 vs. 33.3 +/- 1.4 ml/min per kg, p < 0.0001), although both groups achieved a similar respiratory exchange ratio at peak exercise (1.15 +/- 0.01 vs. 1.19 +/- 0.03, p = 0.13). Quadriceps (582 vs. 652 cm2, p < 0.05) and total leg muscle CSA (1,153 vs. 1,304 cm2, p < 0.005) were lower in patients with chronic HF. Patients were weaker than control subjects (357 +/- 12 vs. 434 +/- 18 N, p < 0.005) and also exhibited greater fatigue at 20 min (79.1% vs. 92.1% of baseline value, p < 0.0001). After correcting strength for quadriceps CSA, significant differences persisted (5.9 +/- 0.2 vs. 7.0 +/- 0.3 N/cm2, p < 0.005), indicating reduced strength per unit muscle. In patients, but not control subjects, muscle CSA significantly correlated with peak absolute VO2 (R = 0.66, p < 0.0001) and is an independent predictor of peak absolute VO2.

CONCLUSIONS

Patients with chronic HF have reduced quadriceps maximal isometric strength. This weakness occurs as a result of both quantitative and qualitative abnormalities of the muscle. With increasing exercise limitation there is increasing muscle weakness. This progressive weakness occurs predominantly as a result of loss of quadriceps bulk. In patients, this muscular atrophy becomes a major determinant of exercise capacity.

Value of natriuretic peptides in assessment of patients with possible new heart failure in primary care

BACKGROUND

The reliability of a clinical diagnosis of heart failure in primary care is poor. Concentrations of natriuretic peptides are high in heart failure. This population-based study examined the predictive value of natriuretic peptides in patients with a new primary-care diagnosis of heart failure.

METHODS

Concentrations of plasma atrial (ANP and N-terminal ANP) and B-type (BNP) natriuretic peptides were measured by radioimmunoassay in 122 consecutive patients referred to a rapid-access heart-failure clinic with a new primary-care diagnosis of heart failure. On the basis of clinical assessment, chest radiography, and transthoracic echocardiography, a panel of three cardiologists decided that 35 (29%) patients met the case definition for new heart failure. ANP and NT-ANP results were available for 117 patients (34 with heart failure) and BNP results for 106 (29 with heart failure).

FINDINGS

Geometric mean concentrations of natriuretic peptides were much higher in patients with heart failure than in those with other diagnoses (29.2 vs 12.4 pmol/L for ANP; 63.9 vs 13.9 pmol/L for BNP; 1187 vs 410.6 pmol/L for NT-ANP; all p < 0.001). At cut-off values chosen to give negative predictive values for heart failure of 98% (ANP > or = 18.1 pmol/L, NT-ANP > or = 537.6 pmol/L, BNP > or = 22.2 pmol/L), the sensitivity, specificity, and positive predictive value for ANP were 97%, 72%, and 55%; for NT-ANP 97%, 66%, and 54%; and for BNP 97%, 84%, and 70%. Addition of ANP or NT-ANP concentration or both did not improve the predictive power of a logistic regression model containing BNP concentration alone.

INTERPRETATION

In patients with symptoms suspected by a general practitioner to be due to heart failure, plasma BNP concentration seems to be a useful indicator of which patients are likely to have heart failure and require further clinical assessment.

Comparison of captopril and ibopamine in mild to moderate heart failure

OBJECTIVE

To determine the effects of ibopamine 100 mg three times daily compared with captopril 25 mg three times daily on exercise capacity in patients with chronic heart failure.

DESIGN

A randomised, double blind, parallel group comparison of the addition of ibopamine versus captopril during a period of 24 weeks.

SETTING

26 outpatient cardiology clinics in seven European countries.

PATIENTS

266 patients, with mild to moderate chronic heart failure (New York Heart Association (NYHA) functional class II, 81% and III, 19%) and evidence of an enlarged left ventricle. Patients received concomitant treatment with diuretics and/or digitalis.

MAIN OUTCOME MEASURE

Exercise duration after 24 weeks of treatment, compared with baseline.

RESULTS

Mean (SD) ejection fraction was 29 (8)% and the baseline exercise duration in the captopril and ibopamine groups 665 (160) and 675 (174) seconds, respectively. At the end of the study, exercise duration had improved in both groups, by 29 seconds in the ibopamine group (P < 0.01), and by 24 seconds in the captopril group (P < 0.05). There was no difference between groups (P = 0.69, 95% confidence interval -22 to 33). NYHA class, signs and symptoms score, and dyspnoea and fatigue index improved equally in both groups. The total number of adverse events was the same in both treatment groups, but gastrointestinal complaints occurred more often in the ibopamine group. The number of patients with premature withdrawals was no different.

CONCLUSIONS

No difference was detected between the effect of captopril and ibopamine on exercise time in patients with mild to moderate heart failure during a treatment period of 24 weeks.

Angiotensin II receptor type 1 mRNA is upregulated in atria of patients with end-stage heart failure

There is increasing evidence that pathological changes in the myocardium during chronic heart failure (CHF) are partly regulated through the activation of the renin-angiotensin system (RAS), an effect mediated by the angiotensin II type 1 receptor (AT1R). We examined the expression of cardiac AT1R mRNA in normal (atria, n=7; ventricle, n=3) and end-stage CHF human hearts (atria, n=8; ventricle, n=14). Tissue was snap-frozen immediately after explantation during orthotopic cardiac transplantation; control specimens were obtained from healthy donor hearts rejected for technical reasons. Northern blots of purified total mRNA from each tissue were hybridized with a random primed radiolabeled probe for the coding sequence of AT1R. Stringent conditions were used for both hybridization (5X SSC, 65 degrees C) and washing (0.5X SSC, 0.1% SDS, 65 degrees C) of the membrane. Left and right atrial tissue showed low levels of AT1R mRNA expression in the controls, with statistically significant upregulation of expression in tissue from pathological hearts; CHF atria 1.28+/-0.86 optical density (OD) units, control atria 0.56+/-0.31 OD units, P=0.05 (mean+/-s.d.). There were undetectable levels in ventricles from either control (2/2) or dilated hearts (7/7). The results were independent of the etiology of the heart failure and suggest that increased levels of atrial AT1R mRNA may occur in response to elevated atrial pressures in heart failure.

Hormonal changes and catabolic/anabolic imbalance in chronic heart failure and their importance for cardiac cachexia

BACKGROUND

The role of hormonal and cytokine abnormalities in the development of cardiac cachexia remains obscure.

METHODS AND RESULTS

Healthy control subjects (n=16) and patients with chronic heart failure (CHF), classified clinically as cachectic (8% to 35% weight loss over > or = 6 months before study, n=16) or noncachectic (n=37), were assessed for markers of disease severity (maximal oxygen consumption, left ventricular ejection fraction, NYHA functional class). These markers were compared with plasma concentrations of potentially important anabolic and catabolic factors. The degree of neurohormonal activation and catabolic/anabolic imbalance was closely related to wasting but not to conventional measures of the severity of heart failure. Compared with control subjects and noncachectic patients, cachectic patients had reduced plasma sodium and increased norepinephrine, epinephrine (all P<.0001), cortisol, tumor necrosis factor (TNF)-alpha (both P<.002), and human growth hormone (P<.05). Insulin-like growth factor-1, testosterone, and estrogen were similar in all groups. Insulin was increased only in the noncachectic patients (P<.005 versus control subjects). Dehydroepiandrosterone was reduced in the cachectic patients (P<.02 versus control subjects). Insulin, cortisol, TNF-alpha, and norepinephrine correlated independently with wasting in CHF (P<.05; multiple regression of these four factors versus percent ideal weight, R2=.50, P<.0001).

CONCLUSIONS

Cachexia is more closely associated with hormonal changes in CHF than conventional measures of the severity of CHF. This study suggests that the syndrome of heart failure progresses to cardiac cachexia if the normal metabolic balance between catabolism and anabolism is altered.

Relation between serum uric acid and lower limb blood flow in patients with chronic heart failure

OBJECTIVE

To determine whether lower limb blood flow is related to serum uric acid concentrations in patients with chronic heart failure, taking into account the hyperuricaemic effects of diuretic treatment and insulin resistance.

DESIGN

Lower limb blood flow was measured at rest and after maximum exercise followed by a five minute period of ischaemia (maximum blood flow) using strain gauge venous occlusion plethysmography. All patients underwent a metabolic assessment, which included an intravenous glucose tolerance test (IVGTT)-to obtain an index of insulin sensitivity- and measurement of serum uric acid.

SETTING

University and hospital departments specialising in cardiology and metabolic medicine.

SUBJECTS

22 patients with chronic heart failure.

RESULTS

Mean (SEM) resting and maximum blood flow values were 2.87 (0.23) and 24.00 (1.83) ml/100 ml/min, respectively. Patients in the upper tertile of serum uric acid had lower maximum blood flow than those in the lowest tertile (15.6 (2.2) v 31.0 (2.1) ml/100 ml/min, P = 0.003). Serum uric acid correlated with maximum blood flow (r = -0.86, P < 0.001), but not with resting blood flow. In stepwise regression analysis, uric acid emerged as the only predictor of maximum blood flow (standardised coefficient = -0.83 (P < 0.001), R2 = 0.68 (P < 0.001)), independently of diuretic dose, age, body mass index, plasma creatinine, fasting and IVGTT glucose and insulin, insulin sensitivity, maximum oxygen uptake and exercise time during the treadmill exercise test, and alcohol intake.

CONCLUSIONS

There is a strong inverse relation between serum uric acid concentrations and maximum leg blood flow in patients with chronic heart failure. Further studies are needed to determine whether serum uric acid can be used as an index of vascular function in cardiovascular diseases.

Effect of reduced muscle bulk on the ventilatory response to exercise in chronic congestive heart failure secondary to idiopathic dilated and ischemic cardiomyopathy

Changing the exercising muscle group alters the ventilatory response to exercise in chronic heart failure. The recognized muscle abnormalities in congestive heart failure may thus contribute to the ventilatory abnormalities of this condition.

Clinical correlates and prognostic significance of the ventilatory response to exercise in chronic heart failure

OBJECTIVES

This study sought to investigate the clinical characteristics of patients with chronic heart failure and an increased ventilatory response to exercise and to examine the prognostic usefulness of this response.

BACKGROUND

The ventilatory response to exercise is increased in many patients with chronic heart failure and may be characterized by the regression slope relating minute ventilation to carbon dioxide output (VE-VCO2 slope) during exercise.

METHODS

One hundred seventy-three consecutive patients (155 men; mean [+/-SD] age 59.8 +/- 11.5 years; radionuclide left ventricular ejection fraction [LVEF] 28.4 +/- 14.6%) underwent cardiopulmonary exercise testing (peak oxygen consumption 18.5 +/- 7.3 ml/kg per min; VE-CO2 slope 34.8 +/- 10.6) over a 2-year period. Using 1.96 standard deviations above the mean VE-VCO2 slope of 68 healthy age-matched subjects (mean slope 26.3 +/- 4.1), we defined a high ventilatory response to exercise as a slope >34.

RESULTS

Eighty-three patients (48%) had an increased VE-VCO2 slope (mean 43.1 +/- 8.9). There was a difference in age (62.2 vs. 57.3 years, p = 0.005), New York Heart Association functional class (2.9 vs. 2.1, p < 0.001), LVEF (24.7 vs. 31.9%, p = 0.0016), peak oxygen consumption (14.9 vs. 21.7 ml/kg per min, p < 0.0001) and radiographic cardiothoracic ratio (0.58 vs. 0.55, p = 0.002) between these patients and those with a normal slope. In the univariate Cox proportional hazards model, the E-VCO2 slope was an important prognostic factor (p < 0.0001). In the multivariate Cox analyses using several variables (age, peak oxygen consumption, VE-VCO2 slope and LVEF), the VE-VCO2 slope gave additional prognostic information (p = 0.018) beyond peak oxygen consumption (p = 0.022). Kaplan-Meier survival curves at 18 months demonstrated a survival rate of 95% in patients with a normal VE-VCO2 slope compared with 69% in those with a high slope (p < 0.0001).

CONCLUSIONS

A high VE-VCO2 slope selects patients with more severe heart failure and is an independent prognostic marker. The VE-VCO2 slope may be used as a supplementary index in the assessment of patients with chronic heart failure.

Elevated soluble CD14 receptors and altered cytokines in chronic heart failure

We hypothesized that in patients with chronic heart failure mesenteric venous congestion leads to increased bowel permeability, bacterial translocation, and thereby endotoxin release; the increased endotoxin challenge then causes immune activation with increased soluble CD14 levels and tumor necrosis factor (TNF)-alpha production. Patients with high soluble CD14 levels (indicative of endotoxin-cell interaction) have markedly increased plasma levels of TNF-alpha, soluble TNF receptors 1 and 2, and intracellular adhesion molecule-1, supporting this hypothesis.

Wasting as independent risk factor for mortality in chronic heart failure

BACKGROUND

Wasting in chronic heart failure (CHF) has long been known but is little investigated. We sought to find out whether the cachectic state in CHF provides additional prognostic information about all-cause mortality.

METHODS

Between June, 1993, and May, 1995, we studied 171 consecutive patients with CHF (mean age 60 years [SD 11; range 27-86]; 17 female). We assessed exercise capacity (peak oxygen consumption; mean 17.5 mL kg-1 min-1 [6.7]), functional status (New York Heart Association [NYHA] class: 21 class I, 63 class II, 68 class III, 19 class IV), and left-ventricular ejection fraction (mean 30% [SD 15]; n = 115). The cachectic status was defined prospectively as a non-intentional documented weight loss of at least 7.5% of previous normal weight (28 patients; range 9-36% or 6-30 kg) during at least 6 months. The Cox proportional-hazards model was used to assess the association of variables with survival, and Kaplan-Meier cumulative survival plots were constructed to estimate the influence of risk factors.

FINDINGS

At the end of follow-up in November, 1996, 49 patients had died (after a mean 324 days [SD 283]). The mean follow-up of the survivors was 834 days (SD 186; range 549-1269). The cachectic state was predictive of 18-month mortality independent of age, NYHA class, left-ventricular ejection fraction, and peak oxygen consumption. Mortality in the cachectic patients (n = 28) was 18% at 3 months, 29% at 6 months, 39% at 12 months, and 50% at 18 months. Patients who had a peak oxygen consumption below 14 mL kg-1 min-1 (n = 53) had mortality at 3, 6, 12, and 18 months of 19%, 30%, 40%, and 51%. 18-month survival was 23% (95% CI 0-46) for the 13 patients with both of these risk factors (cachexia and low peak oxygen consumption) compared with 93% (88-98) in those (n = 103) with neither risk factor (p < 0.0001).

INTERPRETATION

The cachectic state is a strong independent risk factor for mortality in patients with CHF. Combined with a low peak oxygen consumption, it identifies a subset of patients at extremely high risk of death. Assessment of cachexia should be included in transplant programmes and studies that investigate the effect of interventions by survival analyses.

Action: a 30,000 patient-years double-blind, placebo-controlled trial of nifedipine GITS in stable angina. ACTION Research Group

To assess the overall balance between efficacy and safety of the long-action calcium antagonist nifedipine gastrointestinal therapeutic system (GITS) in patients with stable symptomatic coronary artery disease (CAD), a large multicentre placebo-controlled double-blind trial called ACTION has been mounted (A Coronary Disease Trial Investigating Outcome with Nifedipine GITS). Patients are eligible if they have proven CAD on antianginal treatment in stable clinical condition for at least 3 months without heart failure. The left ventricular ejection fraction must be above 40%. Patients not already on lipid-lowering therapy will be evaluated and such treatment will be started based on current guidelines before randomisation. After washout of an already given calcium antagonist, more than 6000 patients in total will be randomised in equal proportions to either nifedipine GITS 60 mg once daily or placebo. The mean clinical follow-up will be 5 years, with no restrictions on concomitant medication (with the exception of digitalis, calcium antagonists and class III antiarrhythmics). The primary end-point will be survival free of major cardiovascular events (i.e. survival free of acute myocardial infarction, emergency coronary angiography, overt heart failure, stroke and peripheral revascularisation). The study has 95% power to detect a significant (p < 0.05) 18% improvement of this end-point and is of sufficient size to exclude an excess mortality of 3.1 per 1000 patient-years. In this first stable angina trial of this size and scope, 185 centres in Canada, Europe, Israel, Australia and New Zealand will participate. Recruitment will start in November 1996 and is planned to be completed in 2 years.

The influence of muscle mass, strength, fatigability and blood flow on exercise capacity in cachectic and non-cachectic patients with chronic heart failure

BACKGROUND

The influence of age, skeletal muscle function and peripheral blood flow on exercise capacity in chronic heart failure patients is controversial, possibly due to variations in skeletal muscle atrophy.

METHODS AND RESULTS

To assess predictors of exercise capacity in patients with clinical cardiac cachexia, we studied 16 cachectic and 39 non-cachectic male chronic heart failure patients of similar age and ejection fraction. All cachectic patients were wasted (% ideal body weight: 81.2 +/- 1.9 vs 105.2 +/- 2.1, P < 0.0001, mean +/- SEM) and had documented weight loss (5-30 kg). Peak oxygen consumption (14.9 +/- 1.4 vs 16.3 +/- 0.6 ml.kg-1, min-1, resting and peak blood flow (plethysmography) and 20 min fatigability (% baseline strength) were all similar between the two groups. Quadriceps strength, muscle size (all P < 0.0001), strength per unit muscle (right: P < 0.05: left: P < 0.001) and 5 min fatigability (P < 0.05) were all lower in cachectic patients. In non-cachectic patients, age (R = 0.48) and quadriceps strength (R = 0.43, all P < 0.01) predicted peak oxygen consumption. Only in cachectic patients did peak blood flow predict peak oxygen consumption significantly (R = 0.72, P = 0.005), whereas age and strength did not. Similar findings were confirmed using other previously published definitions of cardiac cachexia.

CONCLUSIONS

The predictors of exercise capacity change with the development of cardiac cachexia from age and strength to peak blood flow. This shift may be caused by additional endocrine or catabolic, abnormalities active in end stage heart failure.

Effects of dihydrocodeine on chemosensitivity and exercise tolerance in patients with chronic heart failure

OBJECTIVES

We sought to test the hypothesis that suppression of chemosensitivity (respiratory response to arterial blood gases) with dihydrocodeine may improve dyspnea and exercise tolerance in patients with chronic heart failure.

BACKGROUND

Exertional dyspnea is a common limiting symptom in patients with chronic heart failure. The mechanisms underlying this symptom are not fully understood but may be related to increased ventilation caused, in part, by the augmentation of chemosensitivity. Suppression of chemosensitivity with mild opiates may thus improve this symptom as well as exercise tolerance.

METHODS

Twelve men with chronic heart failure (mean [+/-SE] age 65.5 +/- 1.5 years, range 58 to 75; left ventricular ejection fraction 21.3 +/- 3.0%, range 8 to 39) received placebo or dihydrocodeine (1 mg/kg body weight) on two separate days in a randomized, double-blind design. One hour later, hypoxic and hypercapnic chemosensitivities were assessed using the transient inhalations of pure nitrogen and the rebreathing of 7% carbon dioxide in 93% oxygen, followed by treadmill cardiopulmonary exercise testing. The symptoms of dyspnea and fatigue during the exercise test were assessed using a modified Borg scale from 0 to 10.

RESULTS

There was a significant fall in hypoxic and hypercapnic chemosensitivities with dihydrocodeine administration compared with placebo (0.447 +/- 0.096 vs. 0.746 +/- 0.104 liter/min per percent arterial oxygen saturation, p = 0.005; 2,480 +/- 0.234 vs. 2.966 +/- 0.283 liter/min per mm Hg, p = 0.01, respectively). Exercise duration was prolonged from 455 +/- 27 s on placebo to 512 +/- 27 s (p = 0.001) with dihydrocodeine, and peak oxygen consumption increased from 18.0 +/- 0.6 to 19.7 +/- 0.6 ml/kg per min (p = 0.002). The ventilatory response to exercise, characterized by the regression slope relating minute ventilation to carbon dioxide output, decreased from 34.19 +/- 2.35 to 30.85 +/- 1.91 (p = 0.01). With dihydrocodeine administration, the change in the modified Borg score for dyspnea was -0.80 (p = 0.003) at 6 min and -0.33 (p = 0.52) at peak exercise, whereas that for fatigue did not change significantly. Arterial oxygen saturation was maintained during exercise despite dihydrocodeine administration (99.3% at rest vs. 98.9% at peak exercise, p = 0.21).

CONCLUSIONS

Augmented chemosensitivity is important in the pathophysiology of chronic heart failure. Its suppression with dihydrocodeine was associated with a reduction of exercise ventilation, an improvement in exercise tolerance and a decrease in breathlessness. Pharmacologic modulation of chemosensitivity may benefit patients with chronic heart failure and merits further investigation.

17-beta-Estradiol therapy lessens angina in postmenopausal women with syndrome X

OBJECTIVES

We sought to investigate the hypothesis that estrogen replacement therapy ameliorates symptoms in postmenopausal women with syndrome X.

BACKGROUND

Syndrome X (angina pectoris, positive findings on exercise electrocardiography and normal results on coronary angiography) frequently occurs in menopausal women. This observation, in conjunction with the known vasoactive properties of estrogens, suggests that estrogen depletion may contribute to the pathogenesis of syndrome X in some women.

METHODS

Twenty-five postmenopausal patients with syndrome X completed a double-blind, placebo-controlled study of the effect of 17-beta-estradiol cutaneous patches (100 micrograms/24 h) on the frequency of chest pain and on exercise tolerance. Patients were randomly assigned to receive either placebo or 17-beta-estradiol patches for 8 weeks and were then crossed over to the other treatment.

RESULTS

During the placebo phase, patients had a mean of 7.3 episodes of chest pain/10 days. A reduction to 3.7 episodes/10 days was observed during the 17-beta-estradiol phase (p < 0.05). No significant differences were observed between the effects of 17-beta-estradiol and placebo on exercise duration or the results of other cardiologic investigations.

CONCLUSIONS

Estrogen replacement reduces the frequency of chest pain and may be a useful new therapeutic option for treating postmenopausal women with syndrome X.

Exercise limitation in chronic heart failure: central role of the periphery

The symptoms of chronic heart failure (CHF) are predominantly shortness of breath and fatigue during exercise and reduced exercise capacity. Disturbances of central hemodynamic function are no longer considered to be the major determinants of exercise capacity. The two symptoms of fatigue and breathlessness are often considered in isolation. A pulmonary abnormality is usually considered to be the cause of abnormal ventilation, and increased dead space ventilation has come to be accepted as a major cause of the increased ventilation relative to carbon dioxide production seen in CHF. Rather than decreased skeletal muscle perfusion, an intrinsic muscle abnormality is considered to be responsible for fatigue. Another abnormality seen in CHF is persistent sympathetic nervous system activation, which is difficult to explain on the basis of baroreflex activation. There is increasing evidence for the importance of skeletal muscle ergoreceptors or metaboreceptors in CHF. These receptors are sensitive to work performed, and activation results in increased ventilation and sympathetic activation. The ergoreflex appears to be greatly enhanced in CHF. We put forward the "muscle hypothesis" as an explanation for many of the pathophysiologic events in CHF. Impaired skeletal muscle function results in ergoreflex activation. In turn, this causes increased ventilation, thus linking the symptoms of breathlessness and fatigue. Furthermore, ergoreflex stimulation may be responsible for persistent sympathetic activation.

Mode of death in chronic heart failure. A request and proposition for more accurate classification

The proportion of patients reported to die suddenly or from progressive circulatory failure is not consistent among studies of heart failure. Lack of an adequate or consistent classification of how patients die contributes to the current confusion over the mode of death in heart failure. Defining how patients with heart failure die could be important in developing strategies to reduce the continuing high mortality associated with this condition. We identified 27 studies that reported 50 or more deaths among patients with heart failure to ascertain how death was classified. Definitions of sudden death appeared heterogeneous and the majority of studies failed to publish or make reference to how circulatory failure was defined. A framework for the classification of the mode of death has been developed in which clear separation of the activity and place at the time of death, cause of death, mode of death, and events prior to death is made (ACME: Activity, Cause, Mode and Event). This mode of classifying death has been successfully piloted in two mortality studies; AIRE and NETWORK. Classifying mortality in this way will help identify pathways leading to death and hence suggest therapies and strategies to reduce mortality in patients with heart failure, a group of patients whose prognosis remains poor.

Failure to demonstrate myocardial ischaemia in patients with angina and normal coronary arteries. Evaluation by continuous coronary sinus pH monitoring and lactate metabolism

BACKGROUND

Whether myocardial ischaemia is the mechanism underlying chest pain in patients with angina and normal coronary arteriograms is controversial. We sought to detect the presence of transient myocardial ischaemia using continuous monitoring of coronary sinus blood pH during atrial pacing.

METHODS AND RESULTS

We studied 14 patients (eight women, six men, mean age 51 +/- 3 years) with typical exertional angina and normal coronary arteriograms and nine patients with coronary artery disease (two men, seven women, mean age 61 +/- 7 years). Of the 14 patients with normal coronary arteries, eight had a reduced coronary blood flow reserve (< 2.5-fold increase), 11 had an ischaemic-appearing response to exercise testing, six had reversible perfusion detects on exercise thallium scans and one had resting left bundle branch block. All patients underwent continuous pH monitoring of coronary sinus blood at rest and during incremental atrial pacing (up to 160 bpm). Coronary sinus oxygen saturation and myocardial lactate extraction ratio were also evaluated at rest and at peak pacing. Eleven patients with angina and normal coronary arteries and eight with coronary artery disease had angina during pacing. Both patients with angina and normal coronary arteries (n = 13) and patients with coronary artery disease (n = 9) showed a fall in coronary sinus pH (-0.02 +/- 0.02 vs -0.11 +/- 0.03 pH units, respectively, P < 0.01). Coronary sinus oxygen saturation expressed as a percentage dropped by 19 +/- 6% in patients with coronary artery disease and by 6 +/- 2% in patients with angina and normal coronary arteriograms (P < 0.05). Myocardial lactate extraction ratio decreased from 33 +/- 6% to -1.4 +/- 4% in patients with coronary artery disease and from 23 +/- 8% to 20 +/- 8% in those with angina and normal coronary arteriograms. Three patients with angina and normal coronary arteries had a drop in coronary sinus pH > 0.02 pH units (-0.043 +/- 0.006 pH units) and in coronary sinus oxygen saturation > 8% (16 +/- 3%) consistent with myocardial ischaemia.

CONCLUSION

Despite severe chest pain and reduced coronary flow reserve after pacing, most patients with angina and normal coronary arteriograms do not show metabolic evidence of myocardial ischaemia.

Histological abnormalities of muscle from limb, thorax and diaphragm in chronic heart failure

The aim of the study was to compare histological findings in limb and respiratory muscles from control subjects and patients with heart failure of two different aetiologies. Biopsies of the quadriceps femoris, strap, diaphragm and pectoralis major muscles were taken from each group. The control subjects all had normal left ventricular function, and comprised seven undergoing surgical ablation of electrical pathways and 10 undergoing coronary artery surgery. The heart failure group had severely impaired left ventricular function, and were undergoing cardiac transplantation in all except one case. Ten patients with idiopathic dilated cardiomyopathy and seven with heart failure of ischaemic origin were studied. Conventional histochemical techniques and specific anti-myosin immunofluorescent stains were used. There were no consistent differences in fibre type prevalence or diameter between the groups. There were no important histological abnormalities in the two control groups. There were minor/major changes in four of seven patients with ischaemic heart failure but no major abnormality, whilst in the dilated cardiomyopathy group there were five of 10 patients with minor/major changes and three of 10 with major abnormalities (P < 0.001 vs controls). A variety of changes were seen in both groups of heart failure subjects. These were more marked in the dilated cardiomyopathy than ischaemic group, and suggest the presence of fibre type regeneration and/or transformation. Amongst the findings were tubular aggregates, internalization of nuclei, bizzare staining of myosin and staining of neonatal myosin (seven of 14) and the presence of cores (five of 14). Such changes were more prominent in the diaphragm than in the other muscles. In conclusion, histological abnormalities are present in the limb and respiratory muscles from subjects with heart failure. The changes are most marked in subjects with idiopathic dilated cardiomyopathy, suggesting that there may be a generalized cardiac and skeletal myopathy in these subjects. The presence of histological abnormalities in the respiratory muscles may contribute to the pathogenesis of dyspnoea in heart failure.

Neuroendocrine response to standing and mild exercise in patients with untreated severe congestive heart failure and chronic constrictive pericarditis

OBJECTIVES

Plasma hormones at rest in patients with untreated severe congestive cardiac failure are similar to those occurring during heavy exercise in healthy people. This study examines the hypothesis that the neuroendocrine effects of exercise are modified in untreated congestive cardiac failure.

DESIGN

The effect of lying, standing, upright exercise, and recovery on several plasma hormones was measured in healthy controls and 2 groups of patients with severe untreated heart failure. The level of exercise was the same in all groups and low enough to be within the capacity of patients with severe failure.

PATIENTS

There were 12 healthy controls, 9 patients with untreated severe congestive cardiac failure caused by myocardial disease, and 12 patients with untreated constrictive pericarditis.

SETTING

A tertiary referral centre in North India.

RESULTS

Heart rate, noradrenaline, renin activity, aldosterone, cortisol, growth hormone and atrial natriuretic peptide (ANP) were higher in the 2 groups of patients than in the healthy controls during both rest and exercise (P < 0.01 for both comparisons). In general, the effects of this mild degree of exercise were no greater than those of standing. The increase in heart rate during exercise was greater in the group with constrictive pericarditis than in the controls (P = 0.04) and (non-significantly) in congestive heart failure. Apart from these differences the pattern of responses to standing and exercise was similar in the three groups.

CONCLUSIONS

While there was evidence of a broad neuroendocrine activation in patients with congestive cardiac failure, the only abnormal increase during exercise (of marginal significance) was found for renin activity in those with myocardial disease. In patients with untreated congestive failure, a substantially normal endocrine response to exercise was superimposed on abnormal resting concentrations.

Objective assessment of the response to treatment of severe heart failure using a 9-minute walk test on a patient-powered treadmill

BACKGROUND

No previous studies have demonstrated the changes in exercise capacity that occur during treatment of decompensated severe heart failure. The authors assessed the efficacy and safety of using a patient-powered treadmill to objectively measure exercise capacity and its relationships, if any, to symptom scores and body weight.

METHODS AND RESULTS

Changes in time-limited exercise capacity on a patient-powered treadmill were assessed during inpatient treatment of 12 patients with decompensated chronic heart failure (New York Heart Association classes III and IV). Patients performed a 9-minute walk test daily for 7 days and again at the 6-week follow-up examination. They also completed a 24-item symptom score questionnaire. After treatment, there was a rapid, significant increase in total distance walked, with the increase beginning as early as the second day after admission (mean distance walked +/- SEM, 54 +/- 27 m and 174 +/- 54 m on admission and on day 2, respectively, P < .05). Improvement was maintained throughout the period in the hospital and at 6 weeks (P < .001). Patients reported symptomatic improvement, but this did not reach significance until 4 days after admission (P < .05). Weight loss was not significant. Improved exercise capacity correlated with reduced symptoms and weight loss, but preceded these by several days.

CONCLUSIONS

In patients with decompensated chronic heart failure, this exercise test provides a safe, practical, inexpensive, and objective assessment of functional capacity, providing certain advantages over other indices of response to therapy, such as symptom scores and weight loss. Improvement of exercise capacity does not occur concurrently with relief of symptoms and weight loss.

Angiotensin II and contraction of isolated myocytes from human, guinea pig, and infarcted rat hearts

The effects of angiotensin II on myocardial contractility were assessed in isolated cardiac myocyte preparations, using video microscopy with a computerized edge-detection system. Angiotensin II (1 nM-10 microM) did not affect the contraction of rat (n = 10), guinea pig (n = 11), or human ventricular myocytes (n = 8) or of human atrial myocytes (n = 12). Isoproterenol or raised extracellular calcium increased the contraction amplitude of the cardiac myocytes to a maximum of between 150 and 560% above basal, and there were corresponding increases in the velocities of contraction and relaxation. In rat and guinea pig ventricular myocytes 1 microM angiotensin II did not affect the inotropic response to isoproterenol. Seven days after left coronary artery ligation in seven rats, the basal contraction amplitude was reduced in myocytes from the infarcted region (4.0 +/- 1.9%) compared with the noninfarcted region (5.0 +/- 2.8%, P = 0.03) and with myocytes from six sham-operated hearts (5.0 +/- 2.8%, P = 0.03). There was a switch in myosin isoform expression from the V1 to the V3 isoform in myocytes from both the infarcted and noninfarcted regions. Angiotensin II (1 nM-10 microM) had no significant effect on the contraction characteristics of myocytes from the infarcted rat hearts. In conclusion, angiotensin II had no significant inotropic effect on isolated cardiac myocyte preparations from guinea pig ventricle, normal and infarcted rat ventricle, human ventricle, and human atrium.

Endothelin-1 is involved in norepinephrine-induced ventricular hypertrophy in vivo. Acute effects of bosentan, an orally active, mixed endothelin ETA and ETB receptor antagonist

BACKGROUND

Endothelin-1 (ET-1) has potent effects on cell growth and induces hypertrophy of cultured ventricular myocytes. Catecholamines increase expression of ET-1 mRNA by cultured myocytes. We investigated the role of endogenous ET-1 in catecholamine-induced hypertrophy in vivo by studying the effects of continuous norepinephrine infusion on physical and molecular markers of ventricular hypertrophy, ventricular and noncardiac expression of ET-1 mRNA, and the acute effects of bosentan, an orally active ETA and ETB receptor antagonist.

METHODS AND RESULTS

Seventy male Sprague-Dawley rats (175 to 200 g) were divided into four groups: (1) sham-operated rats, (2) norepinephrine-infused rats (600 micrograms.kg-1.h-1 by subcutaneous osmotic pump, up to 7 days), (3) sham-operated rats given bosentan, and (4) norepinephrine-infused rats given bosentan. Bosentan (100 mg/kg once daily) was administered by gavage for 6 days starting 1 day before operation. Norepinephrine caused increases in absolute ventricular weight and ratios of ventricular weight to body weight and ventricular RNA to protein. Ventricular expression of mRNAs for atrial natriuretic factor, skeletal alpha-actin, and beta-myosin heavy chain, which in adult rat ventricle are indicators of hypertrophy, also increased. Ventricular expression of ET-1 mRNA was elevated in the norepinephrine group at 1, 2, and 3 days. By 5 days, this had fallen to control levels. In lung, kidney, and skeletal muscle, norepinephrine did not significantly increase expression of ET-1 mRNA. Bosentan attenuated norepinephrine-induced increases in ventricular weight, ratio of RNA to protein, and expression of skeletal alpha-actin mRNA and beta-myosin heavy chain mRNA at 5 days, but it did not attenuate increased ventricular expression of atrial natriuretic factor mRNA.

CONCLUSIONS

These data suggest that endogenous ET-1 plays a direct role in mediating norepinephrine-induced ventricular hypertrophy in vivo.

Transient autonomic dysfunction precedes ST-segment depression in patients with syndrome X

Increased sympathetic drive has been suggested to play a role in the pathogenesis of syndrome X (angina pectoris, positive exercise testing, and angiographically normal coronary arteries). Heart rate variability (HRV) studies have shown that patients with syndrome X have an imbalance in autonomic nervous system activity (sympathetic predominance). However, it is not known if transient ST-segment depression which occurs in syndrome X during daily activities is related to this autonomic nervous system dysfunction. This study investigates the relation between the response of the autonomic nervous system, as assessed by HRV analysis, and the occurrence of transient ST-segment depression during 24-hour ambulatory electrocardiographic monitoring in 23 patients (4 men and 19 women, mean age 55 +/- 6 years) with syndrome X. The frequency-domain variables of HRV low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.40 Hz) power were measured at 6-minute intervals during the 30 minutes preceding the onset of transient ST-segment depression. Fourteen patients (61%) had > or = 1 episode of ST-segment depression in the 24 hours, whereas the remaining 9 patients (39%) had no significant ST-segment change. HRV measures differed according to whether or not ST-segment depression was associated with increased heart rate. Episodes of ST-segment depression associated with increased heart rate were preceded by a reduction of high-frequency power and an increase in the low-frequency--high-frequency ratio, whereas episodes of ST-segment depression not associated with increased heart rate showed no significant HRV changes. Low-frequency power remained unchanged irrespective of heart rate. Thus, in patients with syndrome X, a sympathovagal imbalance (sympathetic predominance due to vagal tone withdrawal) precedes episodes of ST-segment depression that are associated with an increased heart rate.