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1.
Expert Rev Cardiovasc Ther ; 15(9): 657-665, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28728443

ABSTRACT

INTRODUCTION: Rapid technological advances in computed tomography (CT) have allowed CT coronary angiography (CTCA) to be delivered at low radiation dose and high diagnostic accuracy. Due to its high negative predictive value for coronary artery disease, it has become a gatekeeper for the assessment of patients with chest pain of recent onset. Second line functional assessment of a detected coronary stenosis relies mostly on other imaging modalities. Functional assessment of coronary artery disease by CT is therefore an attractive addition to CTCA. Areas covered: This review will discuss the current evidence base and future development for CT perfusion imaging. Furthermore, this review will discuss CT-derived fractional flow reserve and CT coronary plaque characteristics as alternative approaches for functional evaluation of coronary artery disease. Finally, combining coronary anatomy and functional assessment of coronary flow with myocardial tissue characterization by CT may be attractive allowing triple assessment by CT. Expert commentary: The combined use of CTCA and functional assessment of coronary artery stenosis by CT perfusion or CT-derived fractional flow reserve is an attractive diagnostic pathway that requires further evaluation.


Subject(s)
Computed Tomography Angiography/methods , Coronary Artery Disease/diagnostic imaging , Tomography, X-Ray Computed/methods , Coronary Angiography/methods , Coronary Artery Disease/diagnosis , Coronary Stenosis/diagnostic imaging , Coronary Stenosis/physiopathology , Fractional Flow Reserve, Myocardial , Humans , Plaque, Atherosclerotic/diagnostic imaging , Predictive Value of Tests
2.
Ann Oncol ; 28(8): 1849-1855, 2017 Aug 01.
Article in English | MEDLINE | ID: mdl-28595285

ABSTRACT

BACKGROUND: Women with platinum-resistant ovarian cancer are a heterogeneous group whose median overall survival is 12 months. We hypothesized that their quality of life (QoL) scores would be prognostic. PATIENTS AND METHODS: Data from AURELIA (n = 326), a randomized trial of chemotherapy with or without bevacizumab, were used to identify baseline QoL domains [EORTC (European Organisation for Research and Treatment of Cancer) QLQ-C30 and OV28] that were significantly associated with overall survival in multivariable Cox regression analyses. Patients were classified as having good, medium, or poor risk. Cutpoints were validated in an independent dataset, CARTAXHY (n = 136). Multivariable analyses of significant QoL domains on survival were adjusted for clinicopathological prognostic factors. The additional QoL information was assessed using C statistic. RESULTS: In AURELIA, all domains, except cognitive function, predicted overall survival in univariable analyses. Physical function (P < 0.001) and abdominal/gastrointestinal symptom (P < 0.001) scores remained significant in multivariable models. In high (score <67), medium (67-93), and low (>93) risk categories for physical function, median overall survival was 11.0, 14.7, and 19.3 months, respectively (P < 0.001). In CARTAXHY, median overall survival was 7.9, 16.2, and 23.9 months (P < 0.001), respectively. For high- (>44), medium- (13-44), and low- (<13) risk categories for abdominal/gastrointestinal symptoms, median overall survival was 11.9, 14.3, and 19.7 months in AURELIA (P < 0.001) and 10.5, 19.6, and 24.1 months in CARTAXHY (P = 0.02). Physical function (P = 0.02) and abdominal/gastrointestinal symptoms (P = 0.03) remained independent prognostic factors after adjustment for clinicopathological factors. The C statistic of the full model was 0.71. For QoL factors alone, patient factors alone and disease factors alone, the C statistics were 0.61, 0.61, and 0.67 respectively. CONCLUSIONS: Physical function and abdominal/gastrointestinal symptom scores improved predictions of overall survival over clinicopathological factors alone in platinum-resistant ovarian cancer. This additional prognostic information could improve trial stratification, patient-doctor communication about prognosis, and clinical decision-making. CLINICAL TRIAL REGISTRATION: NCT00976911.


Subject(s)
Organoplatinum Compounds/therapeutic use , Ovarian Neoplasms/drug therapy , Quality of Life , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bevacizumab/administration & dosage , Bevacizumab/therapeutic use , Drug Resistance, Neoplasm , Female , Humans , Organoplatinum Compounds/administration & dosage , Ovarian Neoplasms/physiopathology , Survival Analysis
3.
Sci Total Environ ; 573: 788-798, 2016 Dec 15.
Article in English | MEDLINE | ID: mdl-27592466

ABSTRACT

Phragmites sp. is present worldwide in treatment wetlands though the mechanisms involved in the phytoremediation remain unclear. In this study a quantitative proteomic approach was used to study the prompt response and adaptation of Phragmites to the textile dyeing pollutant, Acid Orange 7 (AO7). Previously, it was demonstrated that AO7 could be successfully removed from wastewater and mineralized in a constructed wetland planted with Phragmites sp. This azo dye is readily taken up by roots and transported to the plant aerial part by the xylem. Phragmites leaf samples were collected from a pilot scale vertical flow constructed wetland after 0.25, 3.25 and 24.25h exposure to AO7 (400mgL-1) immediately after a watering cycle used as control. Leaf soluble protein extraction yielded an average of 1560 proteins in a broad pI range (pH3-10) by two-dimensional gel electrophoresis. A time course comparative analysis of leaf proteome revealed that 40 proteins had a differential abundance compared to control (p<0.05) within a 3.25h period. After 24.25h in contact with AO7, leaf proteome was similar to control. Adaptation to AO7 involved proteins related with cellular signalling (calreticulin, Ras-related protein Rab11D and 20S proteasome), energy production and conversion (adenosine triphosphate synthase beta subunit) carbohydrate transport and metabolism (phosphoglucose isomerase, fructose-bisphosphate aldolase, monodehydroascorbate reductase, frutockinase-1 and Hypothetical protein POPTR_0003s12000g and the Uncharacterized protein LOC100272772) and photosynthesis (sedoheptulose-1,7-bisphosphatase and ferredoxin-NADP+ reductase). Therefore, the quantitative proteomic approach used in this work indicates that mechanisms associated with stress cell signalling, energy production, carbohydrate transport and metabolism as well as proteins related with photosynthesis are key players in the initial chemical stress response in the phytoremediation process of AO7.


Subject(s)
Azo Compounds/toxicity , Benzenesulfonates/toxicity , Coloring Agents/toxicity , Oxidative Stress , Plant Proteins/metabolism , Poaceae/metabolism , Proteome , Water Pollutants, Chemical/toxicity , Adaptation, Biological , Biodegradation, Environmental , Plant Leaves/drug effects , Plant Leaves/metabolism , Poaceae/drug effects , Wetlands
4.
Expert Rev Cardiovasc Ther ; 12(1): 57-69, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24345094

ABSTRACT

Computed tomography coronary angiography (CTCA) is widely accepted in the evaluation of patients with stable chest pain. Its use in patients with unstable chest pain is more controversial. CTCA can be performed alone or with a computed tomography pulmonary angiogram and aortogram as a 'triple rule-out' scan. Published trial data show that discharging a patient with low-risk acute chest pain after a normal CTCA is a very safe thing to do. Length of stay is generally reduced, but radiation exposure is higher and there is more downstream testing, so it is broadly cost-neutral. Future studies should evaluate this approach in intermediate- to high-risk patients.


Subject(s)
Chest Pain/diagnostic imaging , Coronary Angiography , Emergency Service, Hospital , Radiology Department, Hospital , Tomography, X-Ray Computed , Chest Pain/physiopathology , Coronary Angiography/methods , Humans , Risk Factors , Tomography, X-Ray Computed/methods
5.
Br J Surg ; 99(6): 789-97, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22437496

ABSTRACT

BACKGROUND: Secondary cardiac injury has been demonstrated in critical illness and is associated with worse outcomes. The aim of this study was to establish the existence of trauma-induced secondary cardiac injury, and investigate its impact on outcomes in injured patients. METHODS: Injured adult patients eligible for enrolment in the Activation of Coagulation and Inflammation in Trauma 2 study, and admitted to the intensive care unit between January 2008 and January 2010, were selected retrospectively for the study. Markers of cardiac injury (brain natriuretic peptide (BNP), heart-type fatty acid binding protein (H-FABP) and troponin I) were measured on admission, and after 24 and 72 h in blood samples from injured patients. Individual records were reviewed for adverse cardiac events and death. RESULTS: During the study period, 135 patients were enrolled (106 male, 78·5 per cent) with a median age of 40 (range 16-89) years. Eighteen patients (13·3 per cent) had an adverse cardiac event during admission and these events were not associated with direct thoracic injury. The in-hospital mortality rate was higher among the adverse cardiac event cohort: 44 per cent (8 of 18) versus 17·1 per cent (20 of 117) (P = 0·008). Raised levels of H-FABP and BNP at 0, 24 and 72 h, and troponin I at 24 and 72 h, were associated with increased adverse cardiac events. BNP levels were higher in non-survivors on admission (median 550 versus 403 fmol/ml; P = 0·022), after 24 h (794 versus 567 fmol/ml; P = 0·033) and after 72 h (1043 versus 753 fmol/ml; P = 0·036), as were admission troponin I levels. CONCLUSION: Clinical and cardiac biomarker characteristics support the existence of trauma-induced secondary cardiac injury, which is associated with death, and unrelated to direct thoracic injury.


Subject(s)
Fatty Acid-Binding Proteins/metabolism , Heart Diseases/etiology , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Troponin I/blood , Wounds and Injuries/complications , Adolescent , Adult , Aged , Aged, 80 and over , Biomarkers/blood , Fatty Acid Binding Protein 3 , Female , Heart Diseases/blood , Hospital Mortality , Humans , Male , Middle Aged , Prospective Studies , Young Adult
6.
Water Sci Technol ; 58(10): 2017-23, 2008.
Article in English | MEDLINE | ID: mdl-19039183

ABSTRACT

This study focuses on the evaluation of the adequacy and sustainability of a constructed wetland (CW), with vertical flow (VF) design to treat a strongly coloured textile wastewater.Secondly an accidental AO7 overloaded discharge (700 mg l(-1)) was studied. A set of three similar VFCW beds (3x1 m2), operating in series, allowed also the efficient treatment of the AO7 heavy loaded wastewaters. The treated effluent quality enables water reuse for irrigation purposes or within the process.


Subject(s)
Conservation of Natural Resources/methods , Industrial Waste , Textile Industry , Water Purification/methods , Wetlands , Azo Compounds/isolation & purification , Benzenesulfonates/isolation & purification , Biodegradation, Environmental , Pilot Projects , Spectrophotometry, Ultraviolet , Waste Disposal, Fluid
7.
Heart ; 94(6): 781-92, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18480352

ABSTRACT

Multislice computed tomography (MSCT) is an additional potential tool for the assessment of coronary artery disease. It can provide information about stenoses in coronary arteries and coronary artery bypass grafts, ventricular size and function, cardiac structure and masses, pulmonary vein anatomy, myocardial perfusion and coronary artery plaque. In this review the recent developments in CT technology that have made cardiac imaging possible are examined and the benefits of the latest 64-slice and dual-source CT scanners explained. Information on how to perform cardiac CT and evidence for its various clinical applications are given. Problems and limitations of cardiac CT and the radiation dose are discussed. Future developments and the likely impact of this rapidly evolving technique on clinical cardiology are considered.


Subject(s)
Coronary Artery Disease/diagnostic imaging , Coronary Vessels/physiology , Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Coronary Angiography , Coronary Artery Disease/physiopathology , Humans , Practice Guidelines as Topic
8.
Osteoarthritis Cartilage ; 16(8): 855-64, 2008 Aug.
Article in English | MEDLINE | ID: mdl-18222711

ABSTRACT

OBJECTIVE: To determine whether chondroitin sulphate (CS) impedes the migration of primary articular chondrocytes. DESIGN: Articular chondrocytes were isolated from young and skeletally mature bovine animals. Boyden chambers were used to quantify chondrocyte migration on aggrecan in the presence and absence of CS chains. A novel in vitro model of cell migration into articular cartilage explants was designed to visualise and quantify the migration of labelled chondrocytes into cartilage matrix which had been treated with chondroitinase ABC to remove CS chains present. RESULTS: A consistent trend of increased migration with both age groups of a sub-population of chondrocytes was demonstrated on aggrecan in the absence of CS. These data were supported by results from the in vitro model of chondrocyte migration which demonstrated increasing numbers of a chondrocyte sub-population from both age groups of cartilage migrating into the chondroitinase ABC digested cartilage explants with time in culture. Minimal migration of these chondrocytes was demonstrated into phosphate buffered saline (PBS) treated control explants. CONCLUSIONS: We confirm that a sub-population of chondrocytes isolated from both young and skeletally mature articular cartilages have the ability to migrate. We also demonstrate that CS chains inhibit the migration of these articular chondrocytes and that their removal by chondroitinase ABC digestion enhances the migration of these chondrocytes. Such findings may provide a clinical application for improving cell-based cartilage repair strategies by enhancing integration between endogenous and repair tissue.


Subject(s)
Cartilage, Articular/drug effects , Chondrocytes/drug effects , Chondroitin Sulfates/pharmacology , Animals , Cartilage, Articular/cytology , Cattle , Cell Movement/drug effects , Chondrocytes/cytology , Disease Models, Animal , Microscopy, Fluorescence , Wound Healing/drug effects
9.
Water Sci Technol ; 55(7): 127-34, 2007.
Article in English | MEDLINE | ID: mdl-17506429

ABSTRACT

A pulse feed vertical flow constructed wetland (VFCW) proved to be efficient in the treatment of a textile effluent being able to buffer, dilute and treat an Acid Orange (AO7) accidental discharge. The influence of the flooding level (FL) and pulse feed (PF) duration on the removal efficiencies of a VFCW was examined. Average AO7 removal efficiencies of 70% were achieved for an AO7 Inlet concentration of 700 mgl(-1) applied during 15 min cycle(-1) (every three hours) at a hydraulic load of 13 lm(-2) cycle(-1) and an FL of 21%. The VFCW was modelled by analogy with a combination of ideal reactors. The simplest combination that best reproduced the experimental results was an association of 2 reactors in series plus 1 reactor accounting the dead volumes. The model parameters helped to understand the hydrological and kinetic processes occurring in VFCW. Through the model simulation it was shown that 3 VFCW in series were enough to efficiently treat an organic mass load of 76 gAO7 m(-2) day(-1) in 9 hours and fulfil the discharge legislation. In this work it was possible to establish that the overall degradation kinetics was of first order.


Subject(s)
Industrial Waste , Textile Industry , Water Movements , Wetlands , Air , Oxygen , Pilot Projects , Temperature
10.
Water Res ; 40(10): 2055-63, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16635503

ABSTRACT

Biological, aerobic degradation of an azo dye and of the resultant, recalcitrant, aromatic amines in a constructed wetland (CW) was demonstrated for the first time. A vertical-flow CW, planted with Phragmites sp. was fed with 127 mgl(-1) of acid orange 7 (AO7) at hydraulic loads of 28, 40, 53 and 108 l m(-2) day(-1). Color removal efficiencies of up to 99% clearly demonstrate cleavage of the azo bond, also confirmed by the similar AO7 removal and SO(4)(2-) release rates revealing that adsorption onto the matrix was constant. The positive redox potential at the outlet demonstrates that aerobic conditions were present. Chemical oxygen demand and total organic carbon removal efficiencies of up to 93% were also indicative of AO7mineralization. The degradation of sulfanilic acid was confirmed by the presence of NO(3)(-), SO(4)(2-) and secondary metabolites, which suggest at least two degradation pathways leading to a common compound, 3-oxoadipate.


Subject(s)
Azo Compounds/analysis , Poaceae/growth & development , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/analysis , Aerobiosis , Benzenesulfonates , Biodegradation, Environmental , Pilot Projects , Portugal
11.
J Clin Endocrinol Metab ; 90(5): 2675-80, 2005 May.
Article in English | MEDLINE | ID: mdl-15671110

ABSTRACT

Glycogen storage disease type I (GSD-I) is an inherited disorder of carbohydrate metabolism. Hepatic glucose-6-phosphatase is deficient, leading to impaired gluconeogenesis and glycogenolysis. Patients prevent fasting hypoglycemia by frequent feeds of low glycemic index foods. Normal muscle does not contain glucose-6-phosphatase, and GSD-I is usually classified as a hepatic glycogenosis. However, clinical experience has suggested that patients have decreased cardiovascular fitness, but this had not been formally investigated. This paper reports the results of maximal treadmill cardiopulmonary exercise testing in adult patients with GSD-I. It documents a major reduction in exercise capacity in these patients and demonstrates biochemical aspects of exercise that are different from those of normal controls. All patients showed a reduction in exercise capacity, but there was a wide range of exercise tolerance. Additional work needs to address whether improved adherence to or intensification of therapy in adulthood will ameliorate exercise intolerance.


Subject(s)
Exercise , Glycogen Storage Disease Type I/metabolism , Adolescent , Adult , Blood Glucose/analysis , Exercise Test , Fatty Acids, Nonesterified/blood , Female , Humans , Lactic Acid/blood , Male , Oxygen Consumption
12.
Bioresour Technol ; 95(3): 259-68, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15288268

ABSTRACT

For a selection of nine commercially available superabsorbent polymers, the absorption capacity was evaluated for the principal absorption-inhibition constituent of OMW, mineral salts and for phytotoxic-components, the phenolic compounds. A double exponential model was established for electrical conductivities ranging 4.2-25,000 microS cm(-1). For solutions of phenolic compounds ranging 0-0.5 g l(-1), a distribution coefficient near unit was achieved, while for OMW, the phenolic compounds were concentrated inside the gel as the distribution coefficient was 1.4. Correction of OMW pH towards neutrality was found to increase the absorption capacity by up to 35%. The phytotoxicity was assessed by the germination of Lepidium sativum. Inhibition in plant growth occurred for all OMW dilutions without superabsorbent polymers application. For 5% of OMW (COD 5 gl(-1) and 200 ppm of phenolic compounds) immobilised in PNa2 (1 gl(-1)), plant growth was promoted being observed a 120% growth germination, thus indicating that olive mill wastewater detoxification occurred.


Subject(s)
Phenols/chemistry , Salts/chemistry , Waste Disposal, Fluid/methods , Water Pollutants/toxicity , Absorption , Germination , Lepidium/growth & development , Olea , Polymers , Seeds/growth & development , Toxicity Tests
13.
Environ Technol ; 25(1): 89-100, 2004 Jan.
Article in English | MEDLINE | ID: mdl-15027653

ABSTRACT

The detoxification of agro-industrial effluents using superabsorbent polymers is a new and innovative process. Olive mill wastewater constitutes a major environmental problem in Mediterranean countries due to the large volumes generated, the seasonality of the industry, and the high content of polyphenols and organic matter. The application of superabsorbent polymers allows olive mill wastewater to be used as a fertilizer, as it is immobilized, increasing the biological activity that decreases its phytotoxicity, thus making its water, organic matter and mineral content usable for plant nutrition. Various parameters that characterise olive mill wastewater were evaluated after absorption in 2 different superabsorbent polymers (SAP1 and SAP2). The organic matter was equally distributed in both phases, while there was a concentration of protein and sodium in solution. The K:Na ratio decreased from 70:1 to 2:1. The polyphenol desorption from the gel into solution was found to follow Fick's law. The mass transfer coefficients were 0.147 min(-1) and 0.0085 min(-1) for SAP1 and SAP2, respectively. Phytotoxicity tests were carried out with SAP2. Olive mill wastewater in SAP2 with polyphenol concentrations up to 200 mg l(-1) revealed no phytotoxicity, and even stimulated Lepidium sativum growth, while olive mill wastewater without superabsorbent polymer revealed growth inhibition for all concentrations tested. Caffeic acid degradation by the immobilised biomass followed zero order kinetics. Degradation constants of 0.087 mg l(-1) min(-1) gSAP2(-1) and 1.156 mg l(-1) min(-1) gSAP2(-1) were found. Fungi that developed in the plant growth medium were identified as Aspergillus sp. and Penicillium sp.


Subject(s)
Models, Theoretical , Plant Oils , Waste Disposal, Fluid/methods , Water Pollutants/isolation & purification , Water Purification/methods , Adsorption , Agriculture , Aspergillus/growth & development , Aspergillus/isolation & purification , Industrial Waste , Lepidium/growth & development , Olive Oil , Polymers/chemistry , Toxicity Tests , Water Pollutants/toxicity
14.
J Hypertens ; 19(7): 1279-87, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11446718

ABSTRACT

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.


Subject(s)
Baroreflex/physiology , Cardiac Output, Low/physiopathology , Cardiology/methods , Adult , Aged , Aged, 80 and over , Blood Pressure , Chronic Disease , Differential Threshold , Female , Heart Rate , Humans , Male , Middle Aged , Reference Values
15.
J Fam Psychol ; 15(2): 272-87, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11458633

ABSTRACT

Children's reports on their experiences in different family settings (stepfamilies, single-parent families, and intact families), their contact with friends, and the quality of their friendships were studied with data from 238 children drawn from a community sample. A particular focus was on children's confiding and communication: children's recall of communication about family transitions and their current communication about stepfamily issues with family and friends. Friends were found to be key confidants. The relations between children's family lives (confiding, parent-child relationships, family activities, involvement in parental conflict, and communication about stepfamily issues) and their friendships were investigated and found to be linked to biological relatedness and family setting.


Subject(s)
Family/psychology , Interpersonal Relations , Parents , Single-Parent Family/psychology , Adolescent , Child , Female , Humans , Male
18.
Am J Cardiol ; 87(6): 737-42, 2001 Mar 15.
Article in English | MEDLINE | ID: mdl-11249893

ABSTRACT

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.


Subject(s)
Baroreflex/physiology , Blood Pressure , Heart Failure/physiopathology , Heart Rate , Ventricular Premature Complexes/physiopathology , Autonomic Nervous System/physiopathology , Electrocardiography , Female , Heart Failure/complications , Humans , Male , Middle Aged , Prognosis , Signal Processing, Computer-Assisted , Ventricular Premature Complexes/complications
19.
Circulation ; 103(7): 967-72, 2001 Feb 20.
Article in English | MEDLINE | ID: mdl-11181471

ABSTRACT

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.


Subject(s)
Exercise Tolerance , Heart Failure/physiopathology , Respiratory Function Tests/statistics & numerical data , Ventilation/statistics & numerical data , Chronic Disease , Exercise Test/statistics & numerical data , Follow-Up Studies , Heart Failure/diagnosis , Heart Function Tests/statistics & numerical data , Humans , Middle Aged , Multivariate Analysis , Oxygen Consumption , Predictive Value of Tests , Prognosis , Proportional Hazards Models , Risk Assessment , Survival Rate
20.
J Physiol ; 529 Pt 3: 863-70, 2000 Dec 15.
Article in English | MEDLINE | ID: mdl-11118512

ABSTRACT

The role of skeletal muscle ergoreceptors (afferents sensitive to muscle contraction, differentiated into metaboreceptors, sensitive to metabolic changes, and mechanoreceptors, sensitive to mechanical changes) in the genesis of the increased ventilatory drive in chronic heart failure is controversial. We have aimed to clarify the contribution of muscle metaboreceptors in the leg to ventilation and to compare this with the contribution of mechanoreceptors. Eighteen heart failure patients and 12 controls were studied. Metaboreceptor and mechanoreceptor responses were measured in the leg by bicycle exercise with and without regional circulatory occlusion during recovery, and by active and equivalent passive limb movement, respectively.Patients, in comparison with controls, had a lower peak VO2 (Oxygen uptake) (18.1+/-1.6 vs. 24.5+/-2.5 ml min(-1) kg(-1), P< 0.05), and an evident metaboreceptor contribution to the ventilatory response (3.5+/-1.6 vs. -4.0+/-1.3 l min(-1), P<0.001). Passive limb movement increased ventilation in both patients and controls (+3.7+/-0.4 and +2.9+/-0.5 l min(-1) from baseline, P<0.003), but this was associated with an increase in VO2 (+0.1+/-0.01 and +0.1+/-0.02 l min(-1) from baseline, P<0.001). The ratio of the increase in ventilation to the increase in VO2 during passive movement was not significantly higher than that during active exercise for either patients or controls, suggesting a limited contribution from the mechanoreceptors. In chronic heart failure the presence of a muscle metaboreceptor reflex is also demonstrated in the leg, while mechanoreceptors exhibited a non-significant contribution in both patients and controls. The hypothesis of a peripheral origin of symptoms of exertional intolerance in this syndrome is confirmed as being mainly due to metabolic stimulation of the muscle metaboreceptors.


Subject(s)
Cardiac Output, Low/physiopathology , Muscle Contraction/physiology , Muscle, Skeletal/innervation , Muscle, Skeletal/physiopathology , Neurons, Afferent/physiology , Respiratory System/physiopathology , Bicycling , Chronic Disease , Female , Humans , Leg , Male , Mechanoreceptors/physiology , Middle Aged , Motion , Muscle, Skeletal/metabolism , Oxygen Consumption , Reference Values , Reflex/physiology , Respiration
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