Novel endotypes in heart failure: effects on guideline-directed medical therapy.

Aims: We sought to determine subtypes of patients with heart failure (HF) with a distinct clinical profile and treatment response, using a wide range of biomarkers from various pathophysiological domains. Methods and results: We performed unsupervised cluster analysis using 92 established cardiovascular biomarkers to identify mutually exclusive subgroups (endotypes) of 1802 patients with HF and reduced ejection fraction (HFrEF) from the BIOSTAT-CHF project. We validated our findings in an independent cohort of 813 patients. Based on their biomarker profile, six endotypes were identified. Patients with endotype 1 were youngest, less symptomatic, had the lowest N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels and lowest risk for all-cause mortality or hospitalization for HF. Patients with endotype 4 had more severe symptoms and signs of HF, higher NT-proBNP levels and were at highest risk for all-cause mortality or hospitalization for HF [hazard ratio (HR) 1.4; 95% confidence interval (CI) 1.1-1.8]. Patients with endotypes 2, 3, and 5 were better uptitrated to target doses of beta-blockers (P < 0.02 for all). In contrast to other endotypes, patients with endotype 5 derived no potential survival benefit from uptitration of angiotensin-converting enzyme-inhibitor/angiotensin-II receptor blocker and beta-blockers (Pinteraction <0.001). Patients with endotype 2 (HR 1.29; 95% CI 1.10-1.42) experienced possible harm from uptitration of beta-blockers in contrast to patients with endotype 4 and 6 that experienced benefit (Pinteraction for all <0.001). Results were strikingly similar in the independent validation cohort. Conclusion: Using unsupervised cluster analysis, solely based on biomarker profiles, six distinct endotypes were identified with remarkable differences in characteristics, clinical outcome, and response to uptitration of guideline directed medical therapy.

Determinants and clinical outcome of uptitration of ACE-inhibitors and beta-blockers in patients with heart failure: a prospective European study.

INTRODUCTION: Despite clear guidelines recommendations, most patients with heart failure and reduced ejection-fraction (HFrEF) do not attain guideline-recommended target doses. We aimed to investigate characteristics and for treatment-indication-bias corrected clinical outcome of patients with HFrEF that did not reach recommended treatment doses of ACE-inhibitors/Angiotensin receptor blockers (ARBs) and/or beta-blockers. METHODS AND RESULTS: BIOSTAT-CHF was specifically designed to study uptitration of ACE-inhibitors/ARBs and/or beta-blockers in 2516 heart failure patients from 69 centres in 11 European countries who were selected if they were suboptimally treated while initiation or uptitration was anticipated and encouraged. Patients who died during the uptitration period (n = 151) and patients with a LVEF > 40% (n = 242) were excluded. Median follow up was 21 months. We studied 2100 HFrEF patients (76% male; mean age 68 ±12), of which 22% achieved the recommended treatment dose for ACE-inhibitor/ARB and 12% of beta-blocker. There were marked differences between European countries. Reaching <50% of the recommended ACE-inhibitor/ARB and beta-blocker dose was associated with an increased risk of death and/or heart failure hospitalization. Patients reaching 50-99% of the recommended ACE-inhibitor/ARB and/or beta-blocker dose had comparable risk of death and/or heart failure hospitalization to those reaching ≥100%. Patients not reaching recommended dose because of symptoms, side effects and non-cardiac organ dysfunction had the highest mortality rate (for ACE-inhibitor/ARB: HR 1.72; 95% CI 1.43-2.01; for beta-blocker: HR 1.70; 95% CI 1.36-2.05). CONCLUSION: Patients with HFrEF who were treated with less than 50% of recommended dose of ACE-inhibitors/ARBs and beta-blockers seemed to have a greater risk of death and/or heart failure hospitalization compared with patients reaching ≥100%.

Elevated troponin I level assessed by a new high-sensitive assay and the risk of poor outcomes in patients with acute heart failure.

BACKGROUND: The interpretation and clinical usefulness of elevated levels of cardiac troponins in acute heart failure (AHF) remain controversial. We aimed to characterize the relationship between changes in cardiac troponin I (measured using a new high-sensitive immunoassay by single-molecule counting technology, Singulex, Alameda, USA; hs-TnI) during first 48h of hospital stay and patients' characteristics and the outcomes. METHODS AND RESULTS: We measured hs-TnI at baseline, after 24 and 48h in 130 AHF patients (mean age: 65±13years, 77% men). The percentage of patients with elevated hs-TnI (i.e., above the upper reference limit [URL]>10.19pg/mL) were: on admission - 59%, after 24h - 61%, and after 48h - 58%. Elevated baseline level of hs-TnI was associated with more severe dyspnoea on admission but neither peak level nor changes in hs-TnI during first 48h were related to the dyspnoea severity or magnitude of dyspnoea relief. During 1-year follow-up there were 32 (25%) cardiovascular deaths. Neither absolute baseline nor peak values of hs-TnI predicted cardiovascular mortality. Only changes in hs-TnI were independently associated with cardiovascular mortality with the strongest relationship seen in peak change in hs-TnI: patients with an increase vs. remaining patients - hazard ratio (95% confidence interval): 3.22 (1.52-6.82)p=0.002. CONCLUSIONS: Using the new assay (proved to be more sensitive that the other available troponin assays) we observed that approximately 60% of patients with AHF presented elevated hs-TnI above URL during first 48h of hospital stay. Only significant increase in hs-TnI predicted cardiovascular mortality.

Prevalence of AAV1 neutralizing antibodies and consequences for a clinical trial of gene transfer for advanced heart failure.

Adeno-associated virus serotype 1 (AAV1) has many advantages as a gene therapy vector, but the presence of pre-existing neutralizing antibodies (NAbs) is an important limitation. This study was designed to determine: (1) characteristics of AAV NAbs in human subjects, (2) prevalence of AAV1 NAbs in heart failure patients and (3) utility of aggressive immunosuppressive therapy in reducing NAb seroconversion in an animal model. NAb titers were assessed in a cohort of heart failure patients and in patients screened for a clinical trial of gene therapy with AAV1 carrying the sarcoplasmic reticulum calcium ATPase gene (AAV1/SERCA2a). AAV1 NAbs were found in 59.5% of 1552 heart failure patients. NAb prevalence increased with age (P=0.001) and varied geographically. The pattern of NAb titers suggested that exposure is against AAV2, with AAV1 NAb seropositivity due to crossreactivity. The effects of immunosuppression on NAb formation were tested in mini-pigs treated with immunosuppressant therapy before, during and after a single AAV1/SERCA2a infusion. Aggressive immunosuppression did not prevent formation of AAV1 NAbs. We conclude that immunosuppression is unlikely to be a viable solution for repeat AAV1 dosing. Strategies to reduce NAbs in heart failure patients are needed to increase eligibility for gene transfer using AAV vectors.

Increased gene expression of catecholamine-synthesizing enzymes in adrenal glands contributes to high circulating catecholamines in pigs with tachycardia-induced cardiomyopathy.

High levels of circulating catecholamines have been established as fundamental pathophysiological elements of heart failure (HF). However, it is unclear whether the increased gene expression of catecholamine-synthesis enzymes in the adrenal glands contributes to these hormone abnormalities in large animal HF models. We analyzed the mRNA levels of catecholamine-synthesizing enzymes: tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AAAD), dopamine-ß-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) in adrenal glands of 18 pigs with chronic systolic non-ischaemic HF (tachycardia-induced cardiomyopathy due to right ventricle pacing) and 6 sham-operated controls. Pigs with severe HF demonstrated an increased expression of TH and DBH (but neither AAAD nor PNMT) as compared to animals with milder HF and controls (P<0.05 in all cases). The increased adrenal mRNA expression of TH and DBH was accompanied by a reduced left ventricle ejection fraction (LVEF) (P<0.001) and an elevated plasma B-type natriuretic peptide (BNP) (P<0.01), the other indices reflecting HF severity. There was a positive relationship between the increased adrenal mRNA expression of TH and DBH, and the high levels of circulating adrenaline and noradrenaline (all P<0.05). The association with noradrenaline remained significant also when adjusted for LVEF and plasma BNP, suggesting a significant contribution of adrenals to the circulating pool of catecholamines in subjects with systolic HF.

Matrix metalloproteinase 9/neutrophil gelatinase associated lipocalin/tissue inhibitor of metalloproteinasess type 1 complexes are localized within cardiomyocytes and serve as a reservoir of active metalloproteinase in porcine female myocardium.

Matrix metalloproteinase 9 (MMP-9) is crucial for physiological tissue repair and pathophysiological myocardial remodeling. The regulation of its functioning has been shown to be mediated by formation of complexes with tissue inhibitor of metalloproteinases 1 (TIMP-1) and neutrophil gelatinase associated lipocalin (NGAL). We investigated the mRNA and protein expression of MMP-9, TIMP-1 and NGAL, the formation of complexes, their gelatinolytic activity and cellular localization in left ventricle (LV) from 10 female pigs with induced systolic heart failure (HF), 5 control pigs, and a woman with severe HF. The MMP-9, TIMP-1 and NGAL mRNA in LV did not differ between diseased and healthy pigs. In all pigs MMP-9, TIMP-1 and NGAL proteins were present in LV as high molecular weight (HMW) complexes (115, 130, 170 and 220 kDa), and no monomers were found. A 80 and 115 kDa gelatinolytically active bands were present in all LV homogenates. A 130-kDa active band was seen only in LV from pigs with severe HF. Similar results were found in the explanted heart of a female patient with severe HF. The incubation of the homogenates of porcine LV at 37°C resulted in appearance of 88 kDa active band, which was accompanied by a decreased intensity of HMW bands. The incubation of the homogenates of porcine LV (depleted of active MMP-9) with trypsin generated 80 and 115 kDa active bands. Immunohistochemistry revealed the presence of MMP-9 in the cytoplasm of porcine cardiomyocytes, but not in cardiofibroblasts. Our data suggest that MMP-9 originates from cardiomyocytes, forms the gelatinolytically inactive complexes with TIMP-1 and NGAL, present in normal and failing myocardium, likely serving as a reservoir of active MMP-9. Further studies are needed to elucidate the role of these HMW complexes in the extracellular matrix remodeling during the progression of HF, which presence should be considered when developing efficient strategies inhibiting myocardial matrix metalloproteinases.

Effect of short-term rapid ventricular pacing followed by pacing interruption on arterial blood pressure in healthy pigs and pigs with tachycardiomyopathy.

Ventricular tachycardia may lead to haemodynamic deterioration and, in the case of long term persistence, is associated with the development of tachycardiomyopathy. The effect of ventricular tachycardia on haemodynamics in individuals with tachycardiomyopathy, but being in sinus rhythm has not been studied. Rapid ventricular pacing is a model of ventricular tachycardia. The aim of this study was to determine the effect of rapid ventricular pacing on blood pressure in healthy animals and those with tachycardiomyopathy. A total of 66 animals were studied: 32 in the control group and 34 in the study group. The results of two groups of examinations were compared: the first performed in healthy animals (133 examinations) and the second performed in animals paced for at least one month (77 examinations). Blood pressure measurements were taken during chronic pacing--20 min after onset of general anaesthesia, in baseline conditions (20 min after pacing cessation or 20 min after onset of general anaesthesia in healthy animals) and immediately after short-term rapid pacing. In baseline conditions significantly higher systolic and diastolic blood pressure was found in healthy animals than in those with tachycardiomyopathy. During an event of rapid ventricular pacing, a significant decrease in systolic and diastolic blood pressure was found in both groups of animals. In the group of chronically paced animals the blood pressure was lower just after restarting ventricular pacing than during chronic pacing. Cardiovascular adaptation to ventricular tachycardia develops with the length of its duration. Relapse of ventricular tachycardia leads to a blood pressure decrease more pronounced than during chronic ventricular pacing.

Effect of nesiritide in patients with acute decompensated heart failure.

BACKGROUND: Nesiritide is approved in the United States for early relief of dyspnea in patients with acute heart failure. Previous meta-analyses have raised questions regarding renal toxicity and the mortality associated with this agent. METHODS: We randomly assigned 7141 patients who were hospitalized with acute heart failure to receive either nesiritide or placebo for 24 to 168 hours in addition to standard care. Coprimary end points were the change in dyspnea at 6 and 24 hours, as measured on a 7-point Likert scale, and the composite end point of rehospitalization for heart failure or death within 30 days. RESULTS: Patients randomly assigned to nesiritide, as compared with those assigned to placebo, more frequently reported markedly or moderately improved dyspnea at 6 hours (44.5% vs. 42.1%, P=0.03) and 24 hours (68.2% vs. 66.1%, P=0.007), but the prespecified level for significance (P≤0.005 for both assessments or P≤0.0025 for either) was not met. The rate of rehospitalization for heart failure or death from any cause within 30 days was 9.4% in the nesiritide group versus 10.1% in the placebo group (absolute difference, -0.7 percentage points; 95% confidence interval [CI], -2.1 to 0.7; P=0.31). There were no significant differences in rates of death from any cause at 30 days (3.6% with nesiritide vs. 4.0% with placebo; absolute difference, -0.4 percentage points; 95% CI, -1.3 to 0.5) or rates of worsening renal function, defined by more than a 25% decrease in the estimated glomerular filtration rate (31.4% vs. 29.5%; odds ratio, 1.09; 95% CI, 0.98 to 1.21; P=0.11). CONCLUSIONS: Nesiritide was not associated with an increase or a decrease in the rate of death and rehospitalization and had a small, nonsignificant effect on dyspnea when used in combination with other therapies. It was not associated with a worsening of renal function, but it was associated with an increase in rates of hypotension. On the basis of these results, nesiritide cannot be recommended for routine use in the broad population of patients with acute heart failure. (Funded by Scios; ClinicalTrials.gov number, NCT00475852.).

ADQI 7: the clinical management of the Cardio-Renal syndromes: work group statements from the 7th ADQI consensus conference.

Many patients with heart failure have underlying renal dysfunction, and similarly, patients with kidney failure are prone to cardiac failure. This has led to the concept of cardio-renal syndromes, which can be an acute or chronic cardio-renal syndrome, when cardiac failure causes deterioration in renal function, or acute and/or chronic Reno-Cardiac syndrome, when renal dysfunction leads to cardiac failure. Patients who develop these syndromes have increased risk of hospital admission and mortality. Although there are clinical guidelines for managing both heart failure and chronic kidney disease, there are no agreed guidelines for managing patients with cardio-renal and/or Reno-Cardiac syndromes, as these patients have typically been excluded from clinical trials. We have therefore reviewed the currently available published literature to outline a consensus of current best clinical practice for these patients.

Long-term time-course of nocturnal breathing disorders in heart failure patients.

Some important aspects of clinical manifestations of nocturnal breathing disorders in heart failure (HF) patients are still unknown. We questioned whether the severity of these disorders, first, is stable over time; secondly, shows any systematic trend; and, thirdly, can be predicted over time by a single baseline measurement. We studied 79 stable, optimally treated, moderate-to-severe HF patients who performed a monthly cardiorespiratory recording during 1-yr follow-up. According to their behaviour over time, nocturnal breathing disorders were classified as persistent, absent or occasional. During follow-up, clinically relevant breathing disorders were persistent in approximately 50% of the patients, absent in <20% and occasional in approximately 30%. Increasing/decreasing trends were rarely observed. The positive and negative predictive value of baseline measurement for persistent behaviour over time ranged, respectively, from 71% to 91% and from 91% to 95%, depending on different levels of severity of breathing disorders. A large portion of HF patients experience persistent clinically significant nocturnal breathing disorders over long periods of time. Breathing disorders occur irregularly in about one-third of the patients and are negligible in a minority of them. Rarely do they show a steady increase or decrease over time. A single baseline recording predicts a persistent behaviour with moderate-to-high accuracy.

ESPEN Guidelines on Parenteral Nutrition: on cardiology and pneumology.

Nutritional support is becoming a mainstay of the comprehensive therapeutic approach to patients with chronic diseases. Chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD) are frequently associated with the progressive development of malnutrition, due to reduced energy intake, increased energy expenditure and impaired anabolism. Malnutrition and eventually cachexia have been shown to have a negative influence on the clinical course of CHF and COPD, and to impinge on patients' quality of life. Nutritional support in these patients should be therefore considered, particularly to prevent progressive weight loss, since restoration of lean and fat body mass may not be achievable. In CHF and COPD patients, the gastrointestinal tract is normally accessible and functioning. Although recent reports suggest that heart failure is associated with modifications of intestinal morphology, permeability and absorption, the clinical relevance of these are still not clear. Oral supplementation and enteral nutrition should represent the first choices when cardiopulmonary patients need nutritional support, particularly given the potential complications and economic burden of parenteral nutrition. This appropriately preferential enteral approach partly explains the lack of robust clinical trials of the role of parenteral nutrition in CHF and COPD patients. Based on the available evidence collected via PubMed, Medline, and SCOPUS searches, it is recommended that parenteral nutrition is reserved for those patients in whom malabsorption has been documented and in those in whom enteral nutrition has failed.

ESPEN Guidelines on Enteral Nutrition: Cardiology and pulmonology.

These guidelines are intended to give evidence-based recommendations for the use of enteral nutrition (EN) in patients with chronic heart failure (CHF) and chronic obstructive pulmonary disease (COPD). They were developed by an interdisciplinary expert group in accordance with officially accepted standards and are based on all relevant publications since 1985. They have been discussed and accepted in a consensus conference. EN by means of oral nutritional supplements (ONS) or tube feeding (TF) enables nutritional intake to be maintained or increased when normal oral intake is inadequate. No data are yet available concerning the effects of EN on cachexia in CHF patients. However, EN is recommended to stop or reverse weight loss on the basis of physiological plausibility. In COPD patients, EN in combination with exercise and anabolic pharmacotherapy has the potential to improve nutritional status and function. Frequent small amounts of ONS are preferred in order to avoid postprandial dyspnoea and satiety as well as to improve compliance.

Clinical characteristics and methods of treatment of patients with stable coronary heart disease in the primary care settings--the results of the Polish, Multicentre Angina Treatment Pattern (ATP) study.

For further improvement of coronary heart disease (CHD) management large epidemiological studies are required to characterise the real population of patients with CHD, treated in the primary care settings, and to evaluate how the guidelines are implemented in the everyday clinical practice. The aim of the Angina Treatment Pattern (ATP) survey was to characterise (i) the population of patients, treated by the primary care physicians for stable CHD, (ii) the methods applied by the primary care physicians to establish diagnosis of CHD and (iii) the pharmacological therapies for CHD. Across Poland, 397 primary care physicians were randomly selected. They recruited 7420 patients (49% men; mean age, 62 +/- 10 years; range: 25-93 years), treated for stable CHD. The duration of CHD was 7.4 +/- 6.6 years (range: 6 months-50 years), 2750 (37%) patients had myocardial infarction. The following risk factors of CHD were present: arterial hypertension in 58%, dyslipidaemia in 52%, smoking in 40%, family history of CHD in 56% and obesity or overweight in 73% of patients. Primary care physicians based a diagnosis of CHD predominantly on a history of anginal pain (in 33% patients), accompanied either by abnormal resting ECG or positive exercise test (in additional 31% patients). Only in 5% of patients, coronary angiography was applied to diagnose CAD. The following groups of drugs have been used: long-acting nitrates in 90%, anti-platelet drugs or anti-coagulants in 71% (aspirin in 65%), angiotensin-converting enzyme inhibitors in 51%, beta-blockers in 48%, calcium antagonists 31%, hypolipaemic drugs in 23% (statins in 10%) and metabolic agents in 16% of patients. Despite an extensive use of classical anti-anginal drugs (including at least one of the following: long-acting nitrates, beta-blockers, calcium antagonists in 95% of patients), 85% of patients still complained of anginal symptoms. Neither prevalence of angina among patients nor nitroglycerin intake depended on the number of anti-anginal drugs taken (monotherapy vs. combination therapy: 82% vs. 86% and 4.9 vs. 5.3 doses weekly, respectively). Among the primary care physicians, the methods used to establish a CHD diagnosis and the mode of CHD management are far from optimal. The results of the ATP study confirm the need for further intensification of activities to improve the process of diagnosis and management among patients with CHD, treated by the family doctors.

Anaemia is an independent predictor of poor outcome in patients with chronic heart failure.

BACKGROUND: Mild anaemia frequently occurs in patients with chronic heart failure (CHF), particularly in the advanced stages of the disease. The correction of anaemia with erythropoietin is a therapeutic possibility. The aim of this study was to assess prospectively the relationship between the prevalence of anaemia (haemoglobin level18 months in all survivors), and the end-point of the study was all-cause mortality. RESULTS: A total of 176 patients were enrolled (mean age: 63 years, New York Heart Association (NYHA) classification I/II/III/IV: 15/81/51/29; left ventricular ejection fraction (LVEF): 42%, ischaemic aetiology in 62%). In the whole population the mean haemoglobin level was 140+/-15 g/l. Anaemia was found in 18 (10%) patients, and was significantly more common in women than in men (18 vs. 7%, respectively, P=0.02) and in those with most severe CHF symptoms (frequency in NYHA I/II/III/IV: 0/9/10/21%, respectively; NYHA IV vs. I-III, P=0.03), but not related to the other clinical indices. Univariate analysis revealed NYHA class III-IV (hazard ratio 3.8, 95% CI: 1.6-8.9, P=0.003), low LVEF <35% (hazard ratio 2.3, 95% CI: 1.0-4.9, P=0.04) and anaemia (hazard ratio 2.9, 95% CI: 1.2-7.2, P=0.02) as predictors of 18-month mortality. In multivariate analysis, anaemia remained an independent predictor of death when adjusted for NYHA class and LVEF (hazard ratio: 2.6, 95% CI: 1.0-6.5, P=0.04). In anaemic patients, 18-month survival was 67% (95% CI: 45-89%) compared to 87% (81-92%) in patients with a normal haemoglobin level (P=0.016). CONCLUSIONS: Mild anaemia is a significant and independent predictor of poor outcome in unselected patients with CHF. Correction of low haemoglobin level may become an interesting therapeutic option for CHF patients.

Muscle ergoreceptor overactivity reflects deterioration in clinical status and cardiorespiratory reflex control in chronic heart failure.

BACKGROUND: In chronic heart failure (CHF), overactivation of ergoreceptors (afferents sensitive to the metabolic effects of muscular work) may be a link between peripheral changes, sympathetic overactivation, and increased hemodynamic and ventilatory responses to exercise. The relationship between ergoreceptors, autonomic changes, and the progression of the syndrome has not yet been studied. METHODS AND RESULTS: Thirty-eight stable CHF patients (age, 57+/-1 years; ejection fraction, 26+/-2%) were compared with 12 age-matched normal control subjects. The ergoreflex contribution to the ventilatory and hemodynamic responses to exercise, together with peripheral and central chemoreceptor sensitivity, arterial baroreflex sensitivity, plasma norepinephrine, epinephrine, and heart rate variability, were measured. Enhanced ergoreflex effects on ventilation (78+/-2% versus 50+/-8%), peripheral chemosensitivity (0.6+/-0.4 versus 0.2+/-0.1 L/min per percent SaO(2)), and central chemosensitivity (2.9+/-0.2 versus 2.0+/-0.2 L. min(-1). mm Hg(-1)) and an impaired baroreflex function (4.1+/-0.6 versus 9.1+/-5.6 ms/mm Hg) were confirmed in CHF compared with control subjects (P<0.01 in all comparisons). Ergoreceptor overactivity was associated with a worse symptomatic state (NYHA class, P<0.05), lower exercise tolerance (peak VO(2), P<0.05), and pronounced exercise hyperventilation (VE/VCO(2), P<0.01). It was also a strong predictor of increased central chemosensitivity (independently of clinical parameters), baroreflex impairment, and sympathetic activation (plasma catecholamines and heart rate variability indexes; all P<0.05). In multivariate analysis, among all reflexes studied, the ventilatory component of the ergoreflex was the only independent predictor of peak VO(2) and VE/VCO(2). CONCLUSIONS: In CHF, overactivation of the ergoreflex is associated with abnormal cardiorespiratory reflex control, independently of clinical severity. Among impaired reflexes, overactivation of the ergoreflex is an important determinant of exercise hyperventilation and reduced exercise tolerance.

Peripheral chemoreceptor hypersensitivity: an ominous sign in patients with chronic heart failure.

BACKGROUND: Peripheral chemoreceptor hypersensitivity is a feature of abnormal cardiorespiratory reflex control in chronic heart failure (CHF) and may contribute to sympathetic overactivity, attenuated baroreflex sensitivity (BRS), and excessive ventilation during exercise. We studied whether augmented peripheral chemosensitivity carries independent prognostic significance. METHODS AND RESULTS: We assessed peripheral chemosensitivity (ventilatory response to hypoxia using transient inhalation of pure nitrogen) and BRS (phenylephrine and spectral methods) in 80 consecutive CHF patients (age 58+/-9 years; left ventricular ejection fraction [LVEF] 24+/-12%; peak oxygen consumption [peak VO(2)] 18+/-7 mL(-1). min(-1)). CHF patients demonstrated augmented peripheral chemosensitivity and decreased BRS (all P<0.01 versus reference values). During follow-up (median 41 months, >3 years in all survivors), 37 patients died. High peripheral chemosensitivity (>0.72 L. min(-1). %SaO(2)(-1)) predicted impaired survival (hazard ratio 3.2, 95% CI 1.6 to 6.0, P=0.0006). In the 27 patients (34%) with high peripheral chemosensitivity, 3-year survival was 41% (95% CI 22% to 60%) compared with 77% (66% to 89%) in 53 patients with normal chemosensitivity (P=0.0002). In multivariate analyses, augmented chemosensitivity independently predicted death (hazard ratio 2.8, 95% CI 1.5 to 5.5, adjusted for age, peak VO(2), and VE/VCO(2) [P=0.002]; hazard ratio 2.6, 95% CI 1.3 to 5.1, adjusted for age, LVEF, and peak VO(2) [P=0.008]). Depressed BRS was related to unfavorable prognosis in univariate analysis (P=0.05) but not in multivariate analyses. CONCLUSIONS: Hypersensitivity of the peripheral chemoreceptors independently predicts adverse prognosis in ambulatory patients with CHF. This hyperactive excitatory reflex, through its inhibitory effect on the baroreflex, may be the reason for the previously observed prognostic association of the latter.

Effect of altering conditions of the sequence method on baroreflex sensitivity.

BACKGROUND: The sequence method is widely used as a simple, non-invasive measure of baroreflex sensitivity (BRS). This technique, originally described in anaesthetized cats, has been transferred virtually unchanged to humans, without evidence that the optimal values in cats are the same as those in patients with cardiovascular disease. OBJECTIVE: To study the effect of altering the components of the sequence method on the measured BRS in patients with chronic heart failure (CHF) and in normal individuals. METHODS: Eighty patients with CHF [aged 62 +/- 12 years (mean +/- SD)] and 40 normal control individuals [aged 38 +/- 15 years (mean +/- SD)] underwent measurement of heart rate and non-invasive blood pressure. Altering only the shift between blood pressure and R-R interval and the required correlation coefficient of the regression line had no effect on the value of BRS, but had a significant effect on the number of valid sequences. Alteration of the blood pressure or R-R interval thresholds, however, affected not only the number of valid sequences, but also the value of BRS in both groups. In normal controls, agreement with the bolus phenylephrine method was improved by increasing the blood pressure threshold, although this led to a reduction in the number of valid sequences. In patients with CHF, agreement was optimized by decreasing both the blood pressure and R-R interval thresholds. This also had the effect of increasing the number of valid sequences. CONCLUSION: Changes should be made to this technique, to optimize its validity in conscious humans, particularly when applied to patients with attenuated BRS.

Relation of heart rate and blood pressure turbulence following premature ventricular complexes to baroreflex sensitivity in chronic congestive heart failure.

Reduced heart rate variability (HRV) and attenuated baroreflex sensitivity (BS) after myocardial infarction and in patients with chronic congestive heart failure (CHF) are associated with poor prognosis. Recent studies have shown that a large proportion of the prognostic power from HRV measurements is localized in heart rate turbulence immediately after ventricular premature complexes. The mechanism of heart rate turbulence remains unknown. In the present study, we explore its relation to BS. In 45 patients with CHF and > or =3 ectopic beats in a 30-minute period, measurements of RR interval and continuous, noninvasive blood pressure (BP) were studied at rest. In response to an ectopic beat, average heart rate turbulence was 9.4 ms/beat (SD 6.1). Mean BP turbulence was 0.72 mm Hg/beat (SD 0.56). Using the ratio of heart rate and BP turbulence slopes to estimate BS showed good agreement (r = 0.67, p < 0.0001) with the alpha-index method (BSalpha). This relation was attributable to a marked correlation between heart rate turbulence and BSalpha (r = 0.70, p <0.0001); there was no correlation between BP turbulence and the BSalpha (r = 0.1, p = NS). Twenty-nine percent of patients had postectopic pulsus alternans, with a mean decay time of 1.4 beats (SD 0.5). The presence of pulsus alternans was associated with a significantly lower heart rate turbulence slope (6.3 [SEM 1.0] vs 10.7 [SEM 1.2] ms/beat, p = 0.03). Thus, heart rate turbulence is an effective measure of the baroreflex, correlating strongly with a standard measure. This is because it is the heart rate, rather than the BP, response to an ectopic beat that conveys the information relevant to BS measurement.

Enhanced ventilatory response to exercise in patients with chronic heart failure and preserved exercise tolerance: marker of abnormal cardiorespiratory reflex control and predictor of poor prognosis.

BACKGROUND: In patients with chronic heart failure (CHF) and preserved exercise tolerance, the value of cardiopulmonary exercise testing for risk stratification is not known. Elevated slope of ventilatory response to exercise (VE/VCO(2)) predicts poor prognosis in advanced CHF. Derangement of cardiopulmonary reflexes may trigger exercise hyperpnea. We assessed the relationship between cardiopulmonary reflexes and VE/VCO(2)and investigated the prognostic value of (VE/VCO(2)) in CHF patients with preserved exercise tolerance. METHODS AND RESULTS: Among 344 consecutive CHF patients, we identified 123 with preserved exercise capacity, defined as a peak oxygen consumption (PEAK VO(2)) >/=18 mL. kg(-1). min(-1) (age 56 years; left ventricular ejection fraction 28%; peak VO(2) 23.5 mL. kg(-1). min(-1)). Hypoxic and hypercapnic chemosensitivity (n=38), heart rate variability (n=34), baroreflex sensitivity (n=20), and ergoreflex activity (n=20) were also assessed. We identified 40 patients (33%) with high VE/VCO(2) (ie, >34.0). During follow-up (49+/-22 months, >3 years in all survivors), 34 patients died (3-year survival 81%). High VE/VCO(2) (hazard ratio 4.3, P<0.0001) but not peak f1.gif" BORDER="0">O(2) (P=0.7) predicted mortality. In patients with high VE/VCO(2), 3-year survival was 57%, compared with 93% in patients with normal VE/VCO(2) P<0.0001). Patients with high VE/VCO(2) demonstrated impaired reflex control, as evidenced by augmented peripheral (P=0.01) and central (P=0.0006) chemosensitivity, depressed low-frequency component of heart rate variability (P<0.0001) and baroreflex sensitivity (P=0.03), and overactive ergoreceptors (P=0.003) compared with patients with normal VE/VCO(2). CONCLUSIONS: In CHF patients with preserved exercise capacity, enhanced ventilatory response to exercise is a simple marker of a widespread derangement of cardiovascular reflex control; it predicts poor prognosis, which VO(2) does not.