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1

Non-invasive assessment of cardiac output in children  

Microsoft Academic Search

BACKGROUND: Stroke distance, the systolic velocity integral of aortic blood flow, is a linear analogue of stroke volume; its product with heart rate is minute distance, analogous to cardiac output. OBJECTIVE: To investigate the feasibility of assessing cardiac output in children with a simple non-invasive Doppler ultrasound technique, and to determine the normal range of values. METHODS: Peak aortic blood

J R Richardson; J Ferguson; J Hiscox; J Rawles

1998-01-01

2

Assessment of cardiac output by the Doppler ultrasound technique alone  

Microsoft Academic Search

The normal range of aortic blood velocity was established in 140 healthy adults, using a non-invasive Doppler ultrasound technique. Integration of the area under the velocity-time curve for each heart beat gave stroke distance, which, when multiplied by heart rate, gave minute distance. Stroke distance and minute distance are an indication of stroke volume and cardiac output respectively and both

N E Haites; F M McLennan; D H Mowat; J M Rawles

1985-01-01

3

Application of bioreactance for cardiac output assessment during exercise in healthy individuals  

Microsoft Academic Search

In patients with cardiac failure, bioreactance-based cardiac output (CO) monitoring provides a valid non-invasive method for\\u000a assessing cardiac performance during exercise. The purpose of this study was to evaluate the efficacy of this technique during\\u000a strenuous exercise in healthy, trained individuals. Fourteen recreational cyclists, mean (SD) age of 34 (8) years and relative\\u000a peak oxygen uptake of (VO2) 56 (6) ml kg?1 min?1,

Adrian Elliott; James H. Hull; David Nunan; Djordje G. Jakovljevic; David Brodie; Lesley Ansley

2010-01-01

4

A comparative evaluation of electrical velocimetry and inert gas rebreathing for the non-invasive assessment of cardiac output  

Microsoft Academic Search

Background  When assessing the function of the cardiovascular system, cardiac output (CO) is a substantial parameter. For its determination,\\u000a numerous non-invasive techniques have been proposed in the recent years including inert gas rebreathing (IGR) and impedance\\u000a cardiography (ICG). The aim of our study was to evaluate whether a novel ICG algorithm (electrical velocimetry) and IGR can\\u000a be used interchangeably in the

Frederik Trinkmann; Manuel Berger; Ursula Hoffmann; Martin Borggrefe; Jens J. Kaden; Joachim Saur

5

The Determinants of Cardiac Output  

NSDL National Science Digital Library

Part of the Gross Physiology of the Cardiovascular System site, this 22-minute video presentation explains fundamental but often misunderstood concepts about the determinants of cardiac output, using Dr. Anderson's hydraulic model of the cardiovascular system. It is a useful summary and overview of the concepts presented in greater detail in the online text. A transcript of the video presentation is available.

Anderson, Robert M.

2012-01-25

6

Non-invasive cardiac output assessment during moderate exercise: pulse contour compared with CO2 rebreathing.  

PubMed

The arterial pulse contour method called Modelflow 2.1 calculates stroke volume continuously, beat to beat, from the non-invasive blood pressure signal measured by Finapres or Portapres. Portapres is the portable version of Finapres. The purpose of this study was to compare cardiac output (CO) calculated using Modelflow 2.1 (COmf) with CO obtained by the CO2 rebreathing method (COre) during steady state at moderate exercise levels. Twelve subjects visited the laboratory twice and performed submaximal exercise on a bicycle ergometer at 20%, 40% and 60% of their individual peak power output (POpeak). The averaged correlation between COmf and COre gives an r-value of 0.69, whereas the slope and intercept of the regression line were 1.06 and 1.65 respectively. The averaged difference between COmf and COre was 2.27 +/- 3.91 min-1 (mean +/- standard deviation). However, the test-retest difference between COmf and COre was 2.5 +/- 3.1 and 0.5 +/- 1.31 min-1 respectively. These results suggest that Modelflow 2.1 is not an accurate method for estimating CO from non-invasive blood pressure data collected by Portapres during exercise at up to 60% of the individual POpeak corresponding with daily life activity. PMID:10361613

Houtman, S; Oeseburg, B; Hopman, M T

1999-05-01

7

Mathematics and the Heart: Understanding Cardiac Output  

ERIC Educational Resources Information Center

This paper illustrates a biological application of the concepts of relative change and area under a curve, from mathematics. We study two biological measures "relative change in cardiac output" and "cardiac output", which are predictors of heart blockages and other related ailments. Cardiac output refers to the quantity of…

Champanerkar, Jyoti

2013-01-01

8

Pulmonary artery thermodilution cardiac output vs. transpulmonary thermodilution cardiac output in two patients with intrathoracic pathology.  

PubMed

In two adult patients, one with a severe hemorrhage and one with a partial anomalous pulmonary vein, cardiac output (CO) measurements were performed simultaneously by means of the bolus transpulmonary thermodilution technique (COao) and continuous pulmonary artery thermodilution method (CCOpa). In both cases, the methods revealed clinically significant different cardiac output values based upon the site of measurement and the underlying pathology. The assessment of cardiac output (CO) is considered an important part of cardiovascular monitoring of the critically ill patient. Cardiac output is most commonly determined intermittently by the bolus thermodilution technique with a pulmonary artery catheter (COpa). As continuous monitoring of CO is preferable to this intermittent technique, two major techniques have been proposed. Firstly, a nearly continuous thermodilution method (CCOpa) using a heating filament mounted on a pulmonary artery catheter (Baxter Edwards Laboratories, Irvine, CA), with a clinically acceptable accuracy compared with the intermittent bolus technique. Based on these results we assumed CCOpa equivalent to real CO during hemodynamically stable conditions, and secondly, a continuous cardiac output system based on pulse contour analysis (PCCO), such as the PiCCO system (Pulsion Medical System, Munchen, Germany). To calibrate this device, which uses a derivation of the algorithm of Wesseling and colleagues, an independently obtained value of CO by the transpulmonary thermodilution method (COao) is used. Clinical validation studies in patients without underlying intrathoracic pathology, comparing transpulmonary COao with the pulmonary technique (COpa), mostly yielded good agreement. PMID:15101866

Breukers, R B G E; Jansen, J R C

2004-05-01

9

Comparing the accuracy of ES-BC, EIS-GS, and ES Oxi on body composition, autonomic nervous system activity, and cardiac output to standardized assessments  

PubMed Central

Background and purpose The Electro Sensor Complex (ESC) is software that combines three devices using bioelectrical impedance, galvanic skin response, and spectrophotometry: (1) ES-BC (Electro Sensor-Body Composition; LD Technology, Miami, FL) to assess body composition, (2) EIS-GS (Electro Interstitial Scan-Galvanic Skin; LD Technology) to predict autonomic nervous system activity, and (3) ES Oxi (Electro Sensor Oxi; LD Technology) to assess cardiac output. The objective of this study was to compare each to a standardized assessment: ES-BC to dual-energy X-ray absorptiometry (DXA), EIS-GS to heart rate variability, and ES Oxi to BioZ Dx Diagnostic System (BioZ Dx; SonoSite Inc, Bothell, WA). Patients and methods The study was conducted in two waves. Fifty subjects were assessed for body composition and autonomic nervous system activity. Fifty-one subjects were assessed for cardiac output. Results We found adequate relative and absolute agreement between ES-BC and DXA for fat mass (r = 0.97, P < 0.001) with ES-BC overestimating fat mass by 0.1 kg and for body fat percentage (r = 0.92, P < 0.001) with overestimation of fat percentage by 0.4%. For autonomic nervous system activity, we found marginal relative agreement between EIS-GS and heart rate variability by using EIS-GS as the predictor in a linear regression equation (adjusted R2 = 0.56, P = 0.03). For cardiac output, adequate relative and absolute agreement was found between ES Oxi and BioZ Dx at baseline (r = 0.60, P < 0.001), after the first exercise stage (r = 0.79, P < 0.001), and after the second exercise stage (r = 0.86, P < 0.001). Absolute agreement was found at baseline and after both bouts of exercise; ES Oxi overestimated baseline and stage 1 exercise cardiac output by 0.3 L/minute and 0.1 L/minute, respectively, but exactly estimated stage 2 exercise cardiac output. Conclusion ES-BC and ES Oxi accurately assessed body composition and cardiac output compared to standardized instruments, whereas EIS-GS showed marginal predictive ability for autonomic nervous system activity. The ESC software managing the three devices would be useful to help detect complications related to metabolic syndrome, diabetes, and cardiovascular disease and to noninvasively and rapidly manage treatment follow-up. PMID:22915943

Lewis, John E; Tannenbaum, Stacey L; Gao, Jinrun; Melillo, Angelica B; Long, Evan G; Alonso, Yaima; Konefal, Janet; Woolger, Judi M; Leonard, Susanna; Singh, Prabjot K; Chen, Lawrence; Tiozzo, Eduard

2011-01-01

10

RETRACTED ARTICLE: Noninvasive assessment of cardiac output using thoracic electrical bioimpedance in hemodynamically stable and unstable patients after cardiac surgery: a comparison with pulmonary artery thermodilution  

Microsoft Academic Search

Objective  To compare noninvasive cardiac output (CO)measurement obtained with a new thoracic electrical bioimpedance (TEB) device, using\\u000a a proprietary modification of the impedance equation, with invasive measurement obtained via pulmonary artery thermodilution.\\u000a \\u000a \\u000a \\u000a \\u000a Design  Prospective, observational study.\\u000a \\u000a \\u000a \\u000a Setting  Surgical intensive care unit (ICU) of a university-affiliated community hospital.\\u000a \\u000a \\u000a \\u000a Patients and participants  Seventy-four adult patients undergoing elective cardiac surgery with routine pulmonary artery catheter placement.\\u000a \\u000a \\u000a \\u000a Interventions  None.\\u000a \\u000a \\u000a \\u000a Measurements and results  Simultaneous

Stefan Suttner; Thilo Schöllhorn; Joachim Boldt; Jochen Mayer; Kerstin D. Röhm; Katrin Lang; Swen N. Piper

2006-01-01

11

Methods and apparatus for determining cardiac output  

NASA Technical Reports Server (NTRS)

The present invention provides methods and apparatus for determining a dynamical property of the systemic or pulmonary arterial tree using long time scale information, i.e., information obtained from measurements over time scales greater than a single cardiac cycle. In one aspect, the invention provides a method and apparatus for monitoring cardiac output (CO) from a single blood pressure signal measurement obtained at any site in the systemic or pulmonary arterial tree or from any related measurement including, for example, fingertip photoplethysmography.According to the method the time constant of the arterial tree, defined to be the product of the total peripheral resistance (TPR) and the nearly constant arterial compliance, is determined by analyzing the long time scale variations (greater than a single cardiac cycle) in any of these blood pressure signals. Then, according to Ohm's law, a value proportional to CO may be determined from the ratio of the blood pressure signal to the estimated time constant. The proportional CO values derived from this method may be calibrated to absolute CO, if desired, with a single, absolute measure of CO (e.g., thermodilution). The present invention may be applied to invasive radial arterial blood pressure or pulmonary arterial blood pressure signals which are routinely measured in intensive care units and surgical suites or to noninvasively measured peripheral arterial blood pressure signals or related noninvasively measured signals in order to facilitate the clinical monitoring of CO as well as TPR.

Cohen, Richard J. (Inventor); Mukkamala, Ramakrishna (Inventor); Sherman, Derin A. (Inventor)

2010-01-01

12

Cardiac output monitoring: basic science and clinical application: Cardiac output monitoring  

Microsoft Academic Search

Summary Derangements in the circulation are a common feature of sepsis, trauma, major surgery and other critical illnesses. Detailed evaluation of the circulation is therefore an essential aspect of the clinical management of such patients. The use of cardiac output monitoring technology is an increasingly important aspect of evaluating patients in the operating theatre, critical care unit and elsewhere. There

S. Jhanji; J. Dawson; R. M. Pearse

2008-01-01

13

Reduced cardiac output in imported Plasmodium falciparum malaria  

PubMed Central

Background Volume substitution remains subject of controversy in the light of effusions and oedema potentially complicating this highly febrile disease. Understanding the role of myocardial and circulatory function appears to be essential for clinical management. In the present study, cardiac function and cardiac proteins have been assessed and correlated with parasitological and immunologic parameters in patients with imported Plasmodium falciparum malaria. Methods In a prospective case-control study, 28 patients with uncomplicated and complicated P. falciparum malaria were included and findings were compared with 26 healthy controls. Cardiac function parameters were assessed by an innovative non-invasive method based on the re-breathing technique. In addition, cardiac enzymes and pro- and anti-inflammatory cytokines were measured and assessed with respect to clinical symptoms and conditions of malaria. Results Cardiac index (CI) as a measurement of cardiac output (CO) was 21% lower in malaria patients than in healthy controls (2.7 l/min/m2 versus 3.4 l/min/m2; P < 0.001). In contrast, systemic vascular resistance index (SVRI) was increased by 29% (32.6 mmHg?m2/(l/min) versus 23.2 mmHg?m2/(l/min); P < 0.001). This correlated with increased cardiac proteins in patients versus controls: pro-BNP 139.3 pg/ml versus 60.4 pg/ml (P = 0.03), myoglobin 43.6 ?g/l versus 27.8 ?g/l (P = < 0.001). All measured cytokines were significantly increased in patients with malaria. CI, SVRI as well as cytokine levels did not correlate with blood parasite density. Conclusions The results support previous reports suggesting impaired cardiac function contributing to clinical manifestations in P. falciparum malaria. Findings may be relevant for fluid management and should be further explored in endemic regions. PMID:21658247

2011-01-01

14

Newer methods of cardiac output monitoring.  

PubMed

Cardiac output (CO) is the volume of blood ejected by each ventricle per minute and is the product of stroke volume and heart rate. CO can thus be manipulated by alteration in heart rate or rhythm, preload, contractility and afterload. Moreover it gives important information about tissue perfusion and oxygen delivery. CO can be measured by various methods and thermodilution method using pulmonary artery catheter (PAC) is till date considered as gold standard method. Complications associated with PAC led to development of newer methods which are minimally or non-invasive. Newer methods fulfil other properties like continuous and reproducible reading, cost effective, reliable during various physiological states and have fast response time. These methods are validated against the gold standard with good level agreement. In this review we have discussed various newer methods of CO monitoring and their effectiveness in clinical use. PMID:25276302

Mehta, Yatin; Arora, Dheeraj

2014-09-26

15

Newer methods of cardiac output monitoring  

PubMed Central

Cardiac output (CO) is the volume of blood ejected by each ventricle per minute and is the product of stroke volume and heart rate. CO can thus be manipulated by alteration in heart rate or rhythm, preload, contractility and afterload. Moreover it gives important information about tissue perfusion and oxygen delivery. CO can be measured by various methods and thermodilution method using pulmonary artery catheter (PAC) is till date considered as gold standard method. Complications associated with PAC led to development of newer methods which are minimally or non-invasive. Newer methods fulfil other properties like continuous and reproducible reading, cost effective, reliable during various physiological states and have fast response time. These methods are validated against the gold standard with good level agreement. In this review we have discussed various newer methods of CO monitoring and their effectiveness in clinical use.

Mehta, Yatin; Arora, Dheeraj

2014-01-01

16

Continuous cardiac output and mixed venous oxygen saturation monitoring.  

PubMed

Continuous assessment of cardiac output and SVO2 in the critically ill may be helpful in both the monitoring variations in the patient's cardiovascular state and in determining the efficacy of therapy. Commercially available continuous cardiac output (CCO) monitoring systems are based on the pulsed warm thermodilution technique. In vitro validation studies have demonstrated that this method provides higher accuracy and greater resistance to thermal noise than standard bolus thermodilution techniques. Numerous clinical studies comparing bolus with continuous thermodilution techniques have shown this technique similarly accurate to track each other and to have negligible bias between them. The comparison between continuous thermal and other cardiac output methods also demonstrates good precision of the continuous thermal technique. Accuracy of continuous oximetry monitoring using reflectance oximetry via fiberoptics has been assessed both in vitro and in vivo. Most of the studies testing agreement between continuous SVO2 measurements and pulmonary arterial blood samples measured by standard oximetry have shown good correlation. Continuous SVO2 monitoring is often used in the management of critically ill patients. The most recently designed pulmonary artery catheters are now able to simultaneously measure either SVO2 and CCO or SVO2 and right ventricular ejection fraction. This ability to view simultaneous trends of SVO2 and right ventricular performance parameters will probably allow the clinician to graphically see the impact of volume loading or inotropic therapy over time, as well as the influence of multiple factors, including right ventricular dysfunction, on SVO2. However, the cost-effectiveness of new pulmonary artery catheters application remains still questionable because no established utility or therapeutic guidelines are available. PMID:9869547

Cariou, A; Monchi, M; Dhainaut, J F

1998-12-01

17

Cardiac output estimation using arterial blood pressure waveforms  

E-print Network

Cardiac output (CO) is a cardinal parameter of cardiovascular state, and a fundamental determinant of global oxygen delivery. Historically, measurement of CO has been limited to critically-ill patients, using invasive ...

Sun, James Xin

2006-01-01

18

Cardiac power output and its response to exercise in athletes and non-athletes.  

PubMed

Cardiac power output (CPO) is an integrative measure of overall cardiac function as it accounts for both, flow- and pressure-generating capacities of the heart. The purpose of the present study was twofold: (i) to assess cardiac power output and its response to exercise in athletes and non-athletes and (ii) to determine the relationship between cardiac power output and reserve and selected measures of cardiac function and structure. Twenty male athletes and 32 age- and gender-matched healthy sedentary controls participated in this study. CPO was calculated as the product of cardiac output and mean arterial pressure, expressed in watts. Measures of hemodynamic status, cardiac structure and pumping capability were assessed by echocardiography. CPO was assessed at rest and after peak bicycle exercise. At rest, the two groups had similar values of cardiac power output (1·08 ± 0·2 W versus 1·1 ± 0·24 W, P>0·05), but the athletes demonstrated lower systolic blood pressure (109·5 ± 6·2 mmHg versus 117·2 ± 8·2 mmHg, P<0·05) and thicker posterior wall of the left ventricle (9·8 ± 1 mm versus 9 ± 1·1 mm, P<0·05). Peak CPO was higher in athletes (5·87 ± 0·75 W versus 5·4 ± 0·69 W, P<0·05) as was cardiac reserve (4·92 ± 0·66 W versus 4·26 ± 0·61 W, P<0·05), respectively. Peak exercise CPO and reserve were only moderately correlated with end-diastolic volume (r = 0·54; r = 0·46, P<0·05) and end-diastolic left ventricular internal diameter (r = 0·48; r = 0·42, P<0·05), respectively. Athletes demonstrated greater maximal cardiac pumping capability and reserve than non-athletes. The study provides new evidence that resting measures of cardiac structure and function need to be considered with caution in interpretation of maximal cardiac performance. PMID:23522013

Klasnja, Aleksandar V; Jakovljevic, Djordje G; Barak, Otto F; Popadic Gacesa, Jelena Z; Lukac, Damir D; Grujic, Nikola G

2013-05-01

19

Are the arms and legs in competition for cardiac output?  

PubMed

Oxygen transport to working skeletal muscles is challenged during whole-body exercise. In general, arm-cranking exercise elicits a maximal oxygen uptake (VO2max) corresponding to approximately 70% of the value reached during leg exercise. However, in arm-trained subjects such as rowers, cross-country skiers, and swimmers, the arm VO2max approaches or surpasses the leg value. Despite this similarity between arm and leg VO2max, when arm exercise is added to leg exercise, VO2max is not markedly elevated, which suggests a central or cardiac limitation. In fact, when intense arm exercise is added to leg exercise, leg blood flow at a given work rate is approximately 10% less than during leg exercise alone. Similarly, when intense leg exercise is added to arm exercise, arm blood flow and muscle oxygenation are reduced by approximately 10%. Such reductions in regional blood flow are mainly attributed to peripheral vasoconstriction induced by the arterial baroreflex to support the prevailing blood pressure. This putative mechanism is also demonstrated when the ability to increase cardiac output is compromised; during exercise, the prevailing blood pressure is established primarily by an increase in cardiac output, but if the contribution of the cardiac output is not sufficient to maintain the preset blood pressure, the arterial baroreflex increases peripheral resistance by augmenting sympathetic activity and restricting blood flow to working skeletal muscles. PMID:17019302

Secher, Niels H; Volianitis, Stefanos

2006-10-01

20

Transthoracic electrical bioimpedance versus thermodilution technique for cardiac output measurement during mechanical ventilation  

Microsoft Academic Search

To study the possible influence of mechanical ventilation on the accurracy of thoracic electrical bioimpedance (TEI) in the measurement of cardiac output, we determined cardiac output concurrently by TEI using Kubicek's equation and by thermodilution in 8 acutely ill patients who were mechanically ventilated (assist\\/control mode) but who had no underlying respiratory failure. Cardiac outputs were lower with TEI than

J. C. Preiser; A. Daper; J.-N. Parquier; B. Contempré; J.-L. Vincent

1989-01-01

21

Noninvasive estimation of cardiac output with nonprescribed breathing  

Microsoft Academic Search

A noninvasive method to estimate cardiac output\\u000a $$\\\\dot Q$$\\u000a without special patient cooperation was developed by modifying a previous acetylene-helium (C2H2?He) rebreathing technique (ART). Estimation of\\u000a $$\\\\dot Q$$\\u000a using ART is based on a single-compartment model that is valid only under prescribed breathing; e.g., fast, deep breathing,\\u000a and emptying of the rebreathing bag on each breath. To make the ART

Marco E. Cabrera; Gerald M. Saidel; Mark H. Cohen

1991-01-01

22

A critical review of the ability of continuous cardiac output monitors to measure trends in cardiac output.  

PubMed

Numerous cardiac output (CO) monitors have been produced that provide continuous rather than intermittent readings. Bland and Altman has become the standard method for validating their performance against older standards. However, the Bland and Altman method only assesses precision and does not assess how well a device detects serial changes in CO (trending ability). Currently, there is no consensus on how trending ability, or trend analysis, should be performed. Therefore, we performed a literature review to identify articles published between 1997 and 2009 that compared methods of continuous CO measurement. Identified articles were grouped according to measurement technique and statistical methodology. Articles that analyzed trending ability were reviewed with the aim of finding an acceptable statistical method. Two hundred two articles were identified. The most popular methods were pulse contour (69 articles), Doppler (54), bioimpedance (38), and transpulmonary or continuous thermodilution (27). Forty-one articles addressed trending, and of these only 23 provided an in-depth analysis. Several common statistical themes were identified: time plots, regression analysis, Bland and Altman using change in CO (?CO), and the 4-quadrant plot, which used direction of change of ?CO to determine the concordance. This plot was further refined by exclusion of data when values were small. Receiver operating characteristic curves were used to define the exclusion zone. In animal studies, a reliable reference standard such as an aortic flowprobe was frequently used, and regression or time plots could be used to show trending. Clinical studies were more problematic because data collection points were fewer (8-10 per subject). The consensus was to use the 4-quadrant plot with exclusion zones and apply concordance analysis. A concordance rate of >92% when using a 15% zone indicated good trending. A new method of presenting trend data (?CO) on a polar plot is proposed. Agreement was shown by the angle with the horizontal axis and ?CO by the distance from the center. Trending can be assessed by the vertical limits of the data, similar to the Bland and Altman method. PMID:20736431

Critchley, Lester A; Lee, Anna; Ho, Anthony M-H

2010-11-01

23

Comparison of cardiac output determined by different rebreathing methods at rest and at peak exercise  

Microsoft Academic Search

Several rebreathing methods are available for cardiac output (Q\\u000a T) measurement. The aims of this study were threefold: first, to compare values for resting Q\\u000a T produced by the equilibrium-CO2, exponential-CO2 and inert gas-N2O rebreathing methods and, second, to evaluate the reproducibility of these three methods at rest. The third aim was to assess\\u000a the agreement between estimates of peak

Djordje G. Jakovljevic; David Nunan; Gay Donovan; Lynette D. Hodges; Gavin R. H. Sandercock; David A. Brodie

2008-01-01

24

A rebreathing method for measuring lung volume, diffusing capacity and cardiac output in conscious small animals  

Microsoft Academic Search

We developed a multiple gas rebreathing technique for measuring lung diffusing capacity (DLCO), lung volume (VL) and cardiac output simultaneously in conscious spontaneously breathing small animals. Lung volume was measured from the dilution of methane (CH4) or sulfur hexafluoride (SF6) and verified independently by a helium washout technique. Cardiac output and DLCO were estimated from the uptake of acetylene and

Cuneyt Yilmaz; Robert L. Johnson; Connie C. W. Hsia

2005-01-01

25

Equipment review: An appraisal of the LiDCO(TM)plus method of measuring cardiac output  

PubMed Central

The LiDCO™plus system is a minimally/non-invasive technique of continuous cardiac output measurement. In common with all cardiac output monitors this technology has both strengths and weaknesses. This review discusses the technological basis of the device and its clinical application. PMID:15153237

2004-01-01

26

Comparison of cardiac output measurement using the CardioQP oesophageal Doppler with cardiac output measurement using thermodilution technique in children during heart catheterisation.  

PubMed

The minimally invasive CardioQP oesophageal Doppler probe estimates cardiac output by measuring blood flow velocity in the descending aorta. Individual variables to enter are patient's age, weight and height. We measured cardiac output simultaneously with CardioQP and pulmonary artery catheter thermodilution techniques during heart catheterisation in 40 paediatric patients with congenital heart defects. Median [range] age was 8.2 years [0.5-16.7 years], cardiac output values measured by thermodilution and CardioQP were 3.6 l.min(-1) [1.2-7.1 l.min(-1)] and 3.0 l.min(-1) [0.7-6.7 l.min(-1)], respectively. These values showed only moderate correlation (r = 0.809; p < 0.0001). Bias and precision were 0.66 l.min(-1) and 1.79 l.min(-1) (95% limits of agreement: -1.13 to +2.45 l.min(-1)). Based on our preliminary experience, cardiac output values measured by CardioQP in children do not reliably represent cardiac output values compared with the thermodilution technique. We suggest measurement of individual aortic diameter to improve performance of the CardioQP. PMID:18557743

Knirsch, W; Kretschmar, O; Tomaske, M; Stutz, K; Nagdyman, N; Balmer, C; Schmitz, A; Berger, F; Bauersfeld, U; Weiss, M

2008-08-01

27

Measurement of cardiac output by carbon dioxide rebreathing methods.  

PubMed

Cardiac output may be measured noninvasively by applying the Fick principle to CO2; CO2 output is measured by expired gas analysis and the veno-arterial CO2 content difference is obtained from estimates of PVCO2 and PaCO2. PVCO2 is determined using the lung as a tonometer for the equilibration of CO2; two main methods are available. In the Defares or exponential method, a low concentration of CO2 is initially rebreathed. Complete equilibration is not reached between the lung and rebreathing bag and the PvCO2 is calculated as the asymptote of the exponential rise in PETCO2 during rebreathing and prior to recirculation. Even though several mathematical methods can be used to calculate PvCO2, the most precise is an iterative statistical analysis to obtain the best-fit curve for PETCO2 with time, from which PvCO2 is obtained from PETCO2 at 20 seconds after the start of rebreathing. In the Collier or equilibrium method, a bag having CO2 concentration higher than PvCO2 is rebreathed. If an appropriate initial bag volume CO2 has been selected, equilibration will occur in the lung-bag system, recognized as a plateau in the PCO2 rebreathing record. If a plateau is not obtained, PvCO2 can be estimated by extrapolating the line joining the points of expired PCO2 during the 8th and 12th seconds of rebreathing to that of the 20th second. With the equilibrium method, the plateau PCO2 is systematically higher than PvCO2 (downstream effect) and a correction is applied to obtain PvCO2. PaCO2 can be estimated from PETCO2 or from the mixed-expired PCO2 and an assumed physiologic dead space, except in patients with abnormal lung function, in whom PaCO2 must be measured directly. The content of CO2 in blood may be calculated from PCO2 by the equation: In(CCO2) = [0.396 X In(PCO2)] + 2.38 More complex algorithms are available to calculate CCO2 if the pH, hemoglobin, and arterial O2 saturation are widely divergent from resting values. The indirect Fick method applied to CO2 during exercise can be used to obtain a valid and reproducible measurement of Q comparable to that obtained by invasive methods. PMID:2500297

Heigenhauser, G J; Jones, N L

1989-06-01

28

Measurement of cardiac output by use of noninvasively measured transient hemodilution curves with photoacoustic technology.  

PubMed

We present the theoretical basis and experimental verification for cardiac output measurements using noninvasively measured hemodilution curves afforded with an indicator dilution technique and the emerging photoacoustic technology. A photoacoustic system noninvasively tracks a transient hemodilution effect induced by a bolus of isotonic saline as an indicator. As a result, a photoacoustic indicator dilution curve is obtained, which allows to estimate cardiac output from the developed algorithm. The experiments with a porcine blood circulatory phantom system demonstrated the feasibility of this technology towards the development of a noninvasive cardiac output measurement system for patient monitoring. PMID:24877007

Kang, Dongyel; Huang, Qiaojian; Li, Youzhi

2014-05-01

29

Use of the single-breath method of estimating cardiac output during exercise-stress testing.  

NASA Technical Reports Server (NTRS)

The single-breath cardiac output measurement technique of Kim et al. (1966) has been modified for use in obtaining cardiac output measurements during exercise-stress tests on Apollo astronauts. The modifications involve the use of a respiratory mass spectrometer for data acquisition and a digital computer program for data analysis. The variation of the modified method for triplicate steady-state cardiac output measurements was plus or minus 1 liter/min. The combined physiological and methodological variation seen during a set of three exercise tests on a series of subjects was 1 to 2.5 liter/min. Comparison of the modified method with the direct Fick technique showed that although the single-breath values were consistently low, the scatter of data was small and the correlation between the two methods was high. Possible reasons for the low single-breath cardiac output values are discussed.

Buderer, M. C.; Rummel, J. A.; Sawin, C. F.; Mauldin, D. G.

1973-01-01

30

Cardiac output estimation from arterial blood pressure waveforms using the MIMIC II database  

E-print Network

The effect of signal quality on the accuracy of cardiac output (CO) estimation from arterial blood pressure (ABP) was evaluated using data from the Multi-Parameter Intelligent Patient Monitoring for Intensive Care (MIMIC) ...

Chen, Tiffany

2009-01-01

31

Cardiac Output and Central Distribution of Blood Flow in the Human Fetus  

Microsoft Academic Search

Background—The objectives of this study were to establish reference ranges for left and right cardiac output and to investigate blood flow distribution through the foramen ovale, ductus arteriosus, and pulmonary bed in human fetuses. Methods and Results—A prospective study was performed in 222 normal fetuses from 13 to 41 weeks of gestation with high-resolution color Doppler ultrasound. Cardiac output and

Gunther Mielke; Norbert Benda

2010-01-01

32

The effect of cardiac denervation and beta-blockade on control of cardiac output in exercising dogs  

Microsoft Academic Search

Summary  Normal and cardiac denervated dogs, with an electromagnetic aortic flowprobe implanted at least 14 days before the experiments,\\u000a ran at different speeds on a 25% graded treadmill. The experiments were carried out before and after blockade of betareceptors\\u000a in the heart by PO administration of 125 mg·kg?1 practolol per day. Changes in stroke volume, heart rate, and cardiac output were

P. G. A. Versteeg; M. I. M. Noble; J. Stubbs; G. Elzinga

1983-01-01

33

Comparison of bioimpedance versus thermodilution cardiac output during cardiac surgery: Evaluation of a second-generation bioimpedance device  

Microsoft Academic Search

Objective: To compare a second-generation thoracic electrical bioimpedance (TEB) hemodynamic monitoring system with the clinically used pulmonary artery catheter thermodilution (TD-PAC) system. Design: Blinded, simultaneous measurements at specified key time points during surgery. Setting: University teaching hospital cardiac surgical operating rooms. Participants: Forty-seven patients undergoing primary elective coronary artery bypass surgery. Interventions: Timed cardiac output measurements by thermodilution and continuous

Bruce D. Spiess; Muhammad A. Patel; Louise O. Soltow; Ian H. Wright

2001-01-01

34

Echocardiographic assessment of cardiac disease  

NASA Technical Reports Server (NTRS)

The physical principles and current applications of echocardiography in assessment of heart diseases are reviewed. Technical considerations and unresolved points relative to the use of echocardiography in various disease states are stressed. The discussion covers normal mitral valve motion, mitral stenosis, aortic regurgitation, atrial masses, mitral valve prolapse, and idiopathic hypertrophic subaortic stenosis. Other topics concern tricuspic valve abnormalities, aortic valve disease, pulmonic valve, pericardial effusion, intraventricular septal motion, and left ventricular function. The application of echocardiography to congenital heart disease diagnosis is discussed along with promising ultrasonic imaging systems. The utility of echocardiography in quantitative evaluation of cardiac disease is demonstrated.

Popp, R. L.

1976-01-01

35

Type D personality and cardiac output in response to stress  

Microsoft Academic Search

Type D personality is predictive of adverse clinical outcome and psychological distress in cardiac patients. However, the mechanisms by which Type D affects health are largely unknown. This study (1) investigated the relationship between Type D and cardiovascular reactivity to experimentally induced stress and (2) tested the influence of Type D on subjective feelings of stress. Eighty four healthy young

Lynn Williams; Ronan E. O’Carroll; Rory C. O’Connor

2009-01-01

36

Non-invasive measurement of cardiac output by a single breath constant expiratory technique.  

PubMed

A new single breath test has been developed that measures pulmonary blood flow (Qc) and pulmonary tissue volume by using the fact that Qc is proportional to the relationship between the absorption rate of acetylene (C2H2) from the alveolar gas and the rate of change of lung volume during constant expiratory flow. To make these measurements a bag in bottle system with a rolling seal spirometer, a mass spectrometer, and a minicomputer with analogue to digital conversion have been used. Qc was compared with cardiac output measured by the thermodilution technique in 20 patients with cardiac disease; some also had mild chronic obstructive pulmonary disease. The mean (SD) resting Qc for the group was 5.27 (1.22) l/min and the cardiac output measured by thermodilution was 5.30 (1.31) l/min. The mean difference between the two estimations of cardiac output was 0.03 l and the standard deviation of this difference was 0.76 l. The Qc technique was not successful in patients with an FEV1/FVC less than 60%, but seemed to be accurate in those with higher FEV1/FVC values. Correction of Qc for the effect of venous admixture in 14 patients resulted in an average 19% overestimation of cardiac output (6.01 (2.52) l/min v 5.05 (1.64) l/min). It is concluded that cardiac output can be accurately measured in patients with cardiac or mild pulmonary disease. No correction for venous admixture due to ventilation-perfusion mismatch was necessary in these patients, presumably because the large breath used by the technique overcomes most mild ventilation-perfusion maldistribution. These findings, in addition to the non-invasive nature of the technique, suggest potential value for the measurement of cardiac output in various clinical conditions. PMID:6701821

Elkayam, U; Wilson, A F; Morrison, J; Meltzer, P; Davis, J; Klosterman, P; Louvier, J; Henry, W L

1984-02-01

37

Validation of a modified one-step rebreathing technique for measuring exercise cardiac output.  

PubMed

A modification of the Farhi one-step rebreathing technique (1) is described for determining submaximal exercise cardiac output (Q). Factors critical in the estimation of Q are initial rebreathing bag volume and constant bag volume during the maneuver. By substituting a high flow rate analyzer (500 ml.min-1) for the recommended low flow rate mass spectrometer (60 ml.min-1), adding a recirculation circuit from the outlet of the analyzer to an inlet at the base of the rebreathing bag, and reducing the length of sample tubing to the analyzer, we were able to recirculate the subject's expired gas and achieve no loss of bag volume. No statistically significant differences in estimate of cardiac output were noted between the mass spectrometer and LB-2 analyzer with recirculation circuit during submaximal cycling. Heart rate and oxygen uptake were highly correlated with cardiac output and agreed well with the literature, irrespective of the CO2 analyzer system used. A unique feature of our method is that the subject's tidal volume is measured prior to the maneuver and then used as the initial rebreathing bag volume. Varying the bag volume by +/- 0.2 L from the tidal volume had no significant effect on the estimate of cardiac output during exercise. Now quick, reliable, and noninvasive measurements of cardiac output are feasible in subjects--not only in the laboratory but also in the field where a mass spectrometer is not readily portable. PMID:3149188

Szlyk, P C; Evans, K C; Sils, I V

1988-12-01

38

Epi-aortic Doppler measurement of cardiac output in univentricular connection  

PubMed Central

Background In the initial postoperative period after a Fontan-type operation for a univentricular circulation, cardiac output information is important, but cannot be provided by conventional methods due to the surgical reconstruction of the heart. In this regard we investigated the feasibility of epi-aortic Doppler measurements in order to calculate cardiac output. Methods : Epi-aortic cardiac output measurement was compared with Fick measurements as the gold standard in eight patients with a univentricular circulation after a Fontan-type operation. Results The mean diameter of the aorta by epi-aortic measurement was 18 mm (range 14 to 25), by angiography 17 mm (range 10 to 24), correlation coefficient 0.88 (p < 0.05). The mean cardiac output by epi-aortic measurement was 2.8 l.min?1 (range 1.2 to 6.3), by the Fick calculations 1.8 l.min?1 (range 0.8 to 5.0). The correlation coefficient for cardiac output data in aortic diameters up to 20 millimeter in diameter was 0.55 (p < 0.05). Conclusions Epi-aortic Doppler measurement of cardiac output after Fontan type reconstructions could be applied in aortas up to 20 millimeter in diameter. A reasonable correlation with Fick calculations was found. This was supported by Bland–Altman plotting. The method is intrinsically invasive, but application and removal of the device were easy and no complications related to the system were observed. An important restriction is the often present abnormal anatomy, either congenitally or after surgery. PMID:22915911

Bogers, Ad J J C; van den Burg, Martin; Schepp, Ronald; Klein, Jan

2009-01-01

39

Stroke volume and cardiac output hypoxemic hypoxia produced by intravenous infusion of carbon dioxide.  

PubMed

Hypoxia produced by intravenous infusion of gaseous carbon dioxide was associated in conscious rabbits with decreases in cardiac output and stroke volume. At the same time the arterial blood pressure, oxygen uptake and blood pH decreased, whereas carbon dioxide pressure and lactate level in the arterial blood increased. Pulmonary ventilation increased too, due to the rise in the respiratory frequency and tidal volume. The fall in cardiac output and stroke volume explains a great fall of oxygen uptake in response to decrease of oxygen pressure in the blood. PMID:6787834

Lyszczarz, J; Boruta, E

1980-01-01

40

A comparison of transoesophageal echocardiographic Doppler across the aortic valve and the thermodilution technique for estimating cardiac output.  

PubMed

This study was undertaken in order to elucidate the differences between various planes of measurement and Doppler techniques (pulsed- vs. continuous-wave Doppler) across the aortic valve to estimate cardiac output. In 45 coronary artery bypass patients, cardiac output was measured each time using four different Doppler techniques (transverse and longitudinal plane, pulsed- and continuous-wave Doppler) and compared with the thermodilution technique. Measurements were performed after induction of anaesthesia and shortly after arrival in the intensive care unit. Optimal imaging was obtained in 91% of the patients, in whom a total of 82 measurements of cardiac output were performed. The respective mean (SD) areas of the aortic valve were 3.77 (0.71) cm2 in the transverse plane and 3.86 (0.89) cm2 in the longitudinal plane. A correlation of 0.87 was found between pulsed-wave Doppler cardiac output and the thermodilution technique in either transverse or longitudinal plane. Correlation coefficients of 0.82 and 0.84 were found between thermodilution cardiac output and transverse and longitudinal continuous-wave Doppler cardiac output, respectively. Although thermodilution cardiac output is a widely accepted clinical standard, transoesophageal Doppler echocardiography across the aortic valve offers adequate estimations of cardiac output. In particular, pulsed-wave Doppler cardiac output in both the transverse and longitudinal plane provides useful data. PMID:10215707

Poelaert, J; Schmidt, C; Van Aken, H; Hinder, F; Mollhoff, T; Loick, H M

1999-02-01

41

Continuous cardiac output measurement - Aspects of Doppler frequency analysis  

NASA Technical Reports Server (NTRS)

From the suprasternal notch blood flow velocity in the aorta can be measured non-invasively by a Doppler probe. Integration over systole after frequency analysis gives a measure of stroke volume if a separate diameter observation is incorporated. Frequency analysis by a zero crossing counter or by a set of parallel phaselock loops was less effective than a set of bandpass filters. Observations on dogs, baboons and humans before and after exercise or surgery suggest the indications to be useful. Application to judging heart failure by the effect of introducing a volume load is indicated. Changes in output also are measured in freely moving subjects.

Mackay, R. S.; Hechtman, H. B.

1975-01-01

42

Doppler Ultrasound Determination of the Distribution of Human Cardiac Output: Effects of Age and Physical Stresses  

Microsoft Academic Search

Due to its high spatial, temporal, and dynamic resolution, noninvasive Doppler ultrasound can be used to determine the distribution of phasic cardiac output in humans. The effects of ageing and various common physical stresses on combined human major central and regional blood flows have not been reported. We tested the hypothesis that there are no significant age-related differences in steady-state

E. R. Greene; R. C. Roach

2004-01-01

43

Serial changes in cardiac output during normal pregnancy: a Doppler ultrasound study  

Microsoft Academic Search

Objectives: To determine the direction and magnitude of change in cardiac output (CO) during pregnancy. Study design: We performed serial measurements of CO on five occasions from 24 weeks gestation to term and once during the puerperium in 26 normal pregnancies (156 measurements) using Doppler ultrasound measurement of flow velocity profiles and aortic root cross sectional area. Result: CO increased

Terence G. Hennessy; Dermot MacDonald; Marie S. Hennessy; Margaret Maguire; Sean Blake; Hugh A. McCann; Declan D. Sugrue

1996-01-01

44

Real-time cardiac output estimation of the circulatory system under left ventricular assistance  

Microsoft Academic Search

A method for indirect and real-time estimation of the cardiac output of the circulatory system supported by the left ventricular assist device (LVAD) is proposed. This method has low invasiveness and is useful for clinical applications of the LVAD since it needs only two measurements: the rate of blood outflow from the LVAD and the aortic pressure. The method is

Makoto Yoshizawa; Hiroshi Takeda; Makoto Miura; Tomoyuki Yambe; Yoshiaki Katahira; Shin-ichi Nitta

1993-01-01

45

Bioimpedance versus thermodilution cardiac output measurement: The bomed NCCOM3 after coronary bypass surgery  

Microsoft Academic Search

Values obtained for cardiac output (CO) were compared using thermodilution (TD) with those obtained using bioimpedance (Bi) as measured using the Bomed NCCOM3 (Revision 6) in 28 consecutive patients in the first 24h after coronary artery bypass surgery (CABS). In 46 paired measurements made in the first 12 h after CABS Bi values for CO were significantly lower than TD

A. N. Thomas; J. Ryan; B. R. H. Doran; B. J. Pollard

1991-01-01

46

CARDIAC OUTPUT AND BLOOD FLOW DISTRIBUTION DURING SWIMMING AND VOLUNTARY DIVING OF THE TUFTED DUCK (AYTHYA FULIGULA)  

Microsoft Academic Search

Summary Cardiac output (Kb) and blood flow distribution were continuously measured in the tufted duck when diving voluntarily. Blood flows through pulmonary, ischiadic, carotid and brachiocephalic arteries were recorded using miniature pulsed Doppler flow probes. By measuring these flows, cardiac output and blood flow to the leg muscles and to the flight muscles could be calculated. Heart rate and Vb

R. M. BEVAN; P. J. BUTLER

47

THE EFFECT OF EXERCISE ON THE CARDIAC OUTPUT AND BLOOD FLOW DISTRIBUTION OF THE LARGESCALE SUCKER CATOSTOMUS MACROCHEILUS  

Microsoft Academic Search

Summary Cardiac output (Q. ) and blood flow distribution were measured in adult largescale suckers at rest and while swimming. Cardiac output was directly measured using an ultrasonic flowprobe in f ish during the summer (16?C), fall (10?C) and winter (5?C). Largescale suckers were adept at holding station against a current without swimming and, when engaged in this behavior, they

ALAN S. KOLOK; R. MICHAEL SPOONER; ANTHONY P. FARRELL

48

Accuracy and Reliability of Non-invasive Cardiac Output: The Future in Cardiology?  

E-print Network

A new generation of non-invasive cardiac output monitors provides an alternative to using conventional invasive methods such as thermodilution and direct Fick. The Bioz.com measures changes in thoracic electrical bioimpedance (TEB) of the descending aorta. The Innocor uses the principle of inert gas rebreathing. Simultaneous TEB and thermodilution cardiac output measurements were taken from 27 patients undergoing right heart catheterisation. Linear regression analysis showed good correlation between thermodilution and TEB about the line y=0.85x + 0.63 (r=0.91, P<0.0001). Preliminary data from the Innocor suggest comparable accuracy, continuous monitoring, portability, ease of use and low cost for a variety of applications in cardiology. 1.

S Faddy; J Bol; Dwm Muller; St. Vincent’s Hospital

49

Evaluation of cardiac output from a tidally ventilated homogeneous lung model  

Microsoft Academic Search

We used the direct Fick measurements to validate a method for estimating cardiac output by iteratively fitting \\u000a at the mouth to lung model values. This model was run using a series of 50, 30 and 10 breaths to test sensitivity to number of breaths used for fitting. The lung was treated as a catenary two-compartment lung model consisting of a

Habib Benallal; Kenneth C. Beck; Bruce D. Johnson; Thierry Busso

2005-01-01

50

Influence of vagal cooling on cardiac output in normal and beta-blocked exercising dogs  

Microsoft Academic Search

Summary  To study the relative influence of parasympathetic and sympathetic innervation on the early adaptation of cardiac output (CO) to exercise, we determined the time constant and amplitude of the CO change in dogs following a stepwise increase in treadmill velocity. The animals were studied during control conditions, beta-blockade, vagal blockade and combined beta-blockade and vagal blockade. To measure CO, an

P. G. A. Versteeg; P. Borgdorff

1986-01-01

51

Continuous intraoperative noninvasive cardiac output monitoring using a new thoracic bioimpedance device  

Microsoft Academic Search

Objectives: To compare a new noninvasive bioimpedance device with the standard thermodilution method during the intraoperative period in high-risk patients undergoing oncological surgery.Design: Prospectively collected data with retrospective analysis.Setting: The study was undertaken at a university hospital, single institution.Participants: Twenty-three selected adults undergoing extensive, ablative oncological surgery.Interventions: Simultaneous measurements of cardiac output by a new bioimpedance method and the standard

Duraiyah Thangathurai; Christopher Charbonnet; Peter Roessler; Charles C. J. Wo; Maged Mikhail; Roland Yoshida; William C. Shoemaker

1997-01-01

52

Cardiac output measurement: Lack of agreement between thermodilution and thoracic electric bioimpedance in two clinical settings  

Microsoft Academic Search

Study objective: To determine the agreement between thermodilution (TD) and thoracic electric bioimpedance (TEB) techniques in cardiac output (CO) measurements in hyperdynamic kidney recipients and normodynamic patients subjected to radical cystectomy. The main objective was to determine the reliability of TEB in CO measurement.Design: Open two-group study.Setting: Unïversity hospital.Patients: 19 kidney recipients and 5 radical cystectomy patients.Interventions: Radial artery cannula

Mohamed M. Atallah; Atef D. Demain

1995-01-01

53

Evaluation of the tracking potential of a noninvasive estimator of cardiac output.  

PubMed

A robust, automatic measurement system for calculating cardiac output noninvasively has recently been developed. The proposed method relies on fast Fourier transform (FFT) analysis of pulses measured externally at the carotid and femoral pressure points. A transfer function of the aorta is computed from these (calibrated) pressure measurements, and a tapered model of the aorta is parametrically adapted so that its transfer function matches that derived experimentally. Incorporated in the system are a custom routine for digitally filtering pressure data and a simplex optimization algorithm for identification of aortic parameters essential to the calculation of impedance and aortic flow. Once flow has been reconstructed in the time domain it is averaged to a stroke volume and multiplied by the heart rate to yield cardiac output. Flow measurements are computed over several pulses and compared against the standard, invasive procedure of thermodilution. Preliminary results for a dynamic investigation of the method indicate a strong potential for tracking changes in cardiac output over time, thus advocating its use in monitoring hemodynamically unstable patients. PMID:8814389

Redling, J; Akay, M

1996-07-01

54

Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners  

PubMed Central

Purpose. Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). Methods. We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maximal laboratory test and then during a real marathon race (mean performance: 3?hr 30?min ± 45?min). Results. Our data revealed that HR, SV and CO were all in a high but submaximal steady state during the marathon (87.0 ± 1.6%, 77.2 ± 2.6%, and 68.7 ± 2.8% of maximal values, respectively). Marathon performance was inversely correlated with an upward drift in the CO/speed ratio (mL of CO × m?1) (r = ?0.65, P < 0.01) and positively correlated with the runner's ability to complete the race at a high percentage of the speed at maximal SV (r = 0.83, P < 0.0002). Conclusion. Our results showed that marathon performance is inversely correlated with cardiac cost and positively correlated with cardiac endurance. The CO response could be a benchmark for race performance in recreational marathon runners. PMID:22645458

Billat, Veronique L.; Petot, Helene; Landrain, Morgan; Meilland, Renaud; Koralsztein, Jean Pierre; Mille-Hamard, Laurence

2012-01-01

55

Serum cortisol concentration with exploratory cut-off values do not predict the effects of hydrocortisone administration in children with low cardiac output after cardiac surgery  

PubMed Central

OBJECTIVES Low cardiac output syndrome is common after paediatric cardiac surgery. Previous studies suggested that hydrocortisone administration may improve haemodynamic stability in case of resistant low cardiac output syndrome in critically ill children. This study was set up to test the hypothesis that the effects of hydrocortisone on haemodynamics in children with low cardiac output syndrome depend on the presence of (relative) adrenal insufficiency. METHODS A retrospective study was done on paediatric patients who received hydrocortisone when diagnosed with resistant low cardiac output syndrome after paediatric cardiac surgery in the period from 1 November 2005 to 31 December 2008. We studied the difference in effects of treatment with hydrocortisone administration between patients with adrenal insufficiency defined as an exploratory cut-off value of total cortisol of <100 nmol/l and patients with a serum total cortisol of ?100 nmol/l. RESULTS A total of 62 of patients were enrolled, meeting the inclusion criteria for low cardiac output syndrome. Thirty-two patients were assigned to Group 1 (<100 nmol/l) and 30 were assigned to Group 2 (?100 nmol/l). Haemodynamics improved after hydrocortisone administration, with an increase in blood pressure, a decrease in administered vasopressors and inotropic drugs, an increase in urine production and a decrease in plasma lactate concentrations. CONCLUSIONS The effects of treatment with hydrocortisone in children with low cardiac output after cardiac surgery was similar in patients with a low baseline serum cortisol concentration and those with normal baseline cortisol levels. A cortisol value using an exploratory cut-off value of 100 nmol/l for adrenal insufficiency should not be used as a criterion to treat these patients with hydrocortisone. PMID:22761126

Verweij, E.J.; Hogenbirk, Karin; Roest, Arno A.W.; van Brempt, Ronald; Hazekamp, Mark G.; de Jonge, Evert

2012-01-01

56

Cardiac imaging and functional assessment in pregnancy.  

PubMed

There are multiple imaging modalities available for the assessment of pregnant women with known or suspected cardiac disease. Because of its safety and general availability, echocardiography is the preferred study of choice for the evaluation of ventricular function, valvular heart disease, congenital heart disease, evaluation of the aorta, and the estimation of cardiac hemodynamics in a pregnant patient. Cardiac MRI can be performed, especially for diseases of the aorta and complex congenital heart disease. Radiation exposure for the fetus and the mother will be discussed in the use of CT angiography, nuclear imaging, and left-heart catheterization including coronary angiography for specific indications in the pregnant woman. The use of exercise testing during pregnancy for functional assessment will be presented. PMID:25037513

Waksmonski, Carol A

2014-08-01

57

The validity of trans-esophageal Doppler ultrasonography as a measure of cardiac output in critically ill adults  

Microsoft Academic Search

ObjectiveTo determine the validity of the esophageal Doppler monitor (EDM) and echo-esophageal Doppler (Echo-ED) in measuring cardiac output in the critically ill.DesignSystematic search of relevant international literature and data synthesis.Search strategyLiterature search (1989–2003) using Ovid interface to Medline, Embase and Cochrane databases aimed at finding studies comparing EDM or Echo-ED cardiac output with that derived from simultaneous pulmonary artery thermodilution

Paul M. Dark; Mervyn Singer

2004-01-01

58

Automated non-invasive measurement of cardiac output: comparison of electrical bioimpedance and carbon dioxide rebreathing techniques  

Microsoft Academic Search

Two commercial automated, non-invasive systems for estimation of cardiac output were evaluated. Values of cardiac output obtained by electrical bioimpedance cardiography (BoMed NCCOM3 machine) were compared with values derived from an indirect Fick technique that uses carbon dioxide rebreathing (Gould 9000 IV system) during 103 simultaneous measurements made at rest in 19 randomly selected subjects and on exercise in 11

S A Smith; A E Russell; M J West; J Chalmers

1988-01-01

59

The comparison of a novel continuous cardiac output monitor based on pulse wave transit time and echo Doppler during exercise.  

PubMed

A new technology called estimated continuous cardiac output (esCCO) uses pulse wave transit time (PWTT) obtained from an electrocardiogram and pulse oximeter to measure cardiac output (CO) non-invasively and continuously. This study was performed to evaluate the accuracy of esCCO during exercise testing. We compared esCCO with CO measured by the echo Doppler aortic velocity-time integral (VTIao_CO). The correlation coefficient between esCCO and VTIao_CO was r= 0.87 (n= 72). Bias and precision were 0.33 ± 0.95 L/min and percentage error was 31%. The esCCO could detect change in VTIao_CO larger than 1 L/min with a concordance rate of 88%. In polar plot, 83% of data are within 0.5 L/min, and 100% of data are within 1 L/min. Those results show the acceptable accuracy and trend ability of esCCO. Change in pre-ejection period (PEP) measured by using M-mode of Diagnostic Ultrasound System accounted for approximately half of change in PWTT. This indicates that PEP included in PWTT has an impact on the accuracy of esCCO measurement. In this study, the validity of esCCO during exercise testing was assessed and shown to be acceptable. The result of this study suggests that we can expand its application. PMID:23365874

Sugo, Yoshihiro; Sakai, Tomoyuki; Terao, Mami; Ukawa, Teiji; Ochiai, Ryoichi

2012-01-01

60

NOTE: Increasing cardiac output and decreasing oxygenation sequence in pump twins of acardiac twin pregnancies  

NASA Astrophysics Data System (ADS)

An acardiac twin pregnancy is a rare but serious complication of monochorionic twinning and consists of an acardiac twin and a pump twin. The acardiac twin is a severely malformed fetus that lacks most organs, particularly a heart, but grows during pregnancy because it is perfused by the developmentally normal pump twin via a set of arterioarterial and venovenous placental anastomoses. Pump twins die intrauterine or neonatally in about 50% of the cases. Because the effects of an acardiac mass on the pump twin's development are incompletely known, methods for outcome prognosis are currently not available. We sought to derive simple relations for the pump twin's excess cardiac output and decreased oxygenation and to use available clinical cases for a preliminary test of the model. As a method, we used a theoretical flow model to represent the fetoplacental circulation of an acardiac twin pregnancy and estimated blood deoxygenation and reoxygenation following perfusion of the two bodies and placentas, respectively. The results show the pump twin's excess cardiac output and decrease of venous oxygen saturation to depend on the ratio of pump twin to acardiac twin umbilical blood flow, whose ratio can be measured by ultrasonography. The clinical cases show a decreasing umbilical flow ratio with gestation. In conclusion, prospective serial study is necessary to test whether measurement of umbilical flow ratios allows monitoring the pump twin's pathophysiologic development, possibly resulting in a guideline for prognosis of pump twin survival.

van Gemert, Martin J. C.; Umur, Asli; van den Wijngaard, Jeroen P. H. M.; Van Bavel, Ed; Vandenbussche, Frank P. H. A.; Nikkels, Peter G. J.

2005-02-01

61

Training is required to improve the reliability of esophageal doppler to measure cardiac output in critically ill patients  

Microsoft Academic Search

Objectives: Assessment of and effect of training on reliability of esophageal Doppler (ED) versus thermodilution (TD) for cardiac output\\u000a (CO) measurement.\\u000a \\u000a \\u000a Design: Prospective study.\\u000a \\u000a \\u000a \\u000a \\u000a Setting: Intensive care unit of a university hospital.\\u000a \\u000a \\u000a \\u000a \\u000a Patients: 64 consecutive critically ill patients requiring a pulmonary artery catheter, sedation, and mechanical ventilation.\\u000a \\u000a \\u000a \\u000a \\u000a Interventions: Esophageal Doppler CO measurements were performed by the same operator, whereas TD

J. Y. Lefrant; P. Bruelle; A. G. M. Aya; G. Saïssi; M. Dauzat; J. E. de La Coussaye; J. J. Eledjam

1998-01-01

62

Design and assessment of cardiac SPECT systems  

NASA Astrophysics Data System (ADS)

Single-photon emission computed tomography (SPECT) is a modality widely used to detect myocardial ischemia and myocardial infarction. Objectively assessing and comparing different SPECT systems is important so that the best detectability of cardiac defects can be achieved. Whitaker, Clarkson, and Barrett's study on the scanning linear observer (SLO) shows that the SLO can be used to estimate the location and size of signals. One major advantage of the SLO is that it can be used with projection data rather than reconstruction data. Thus, this observer model assesses overall hardware performance independent by any reconstruction algorithm. In addition, we will show that the run time of image-quality studies is significantly reduced. Several systems derived from the GE CZT-based dedicated cardiac SPECT camera Discovery 530c design, which is officially named the Alcyone Technology: Discovery NM 530c, were assessed using the performance of the SLO for the task of detecting cardiac defects and estimating the properties of the defects. Clinically, hearts can be virtually segmented into three coronary artery territories: left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA). One of the most important functions of a cardiac SPECT system is to produce images from which a radiologist can correctly predict in which territory the defect exists. A good estimation of the defect extent from the images is also very helpful for determining the seriousness of the myocardial ischemia. In this dissertation, both locations and extent of defects were estimated by the SLO, and system performance was assessed using localization receiver operating characteristic (LROC) / estimation receiver operating characteristic (EROC) curves. Area under LROC curve (AULC) / area under EROC curve (AUEC) and true positive fraction (TPF) at specific false positive fraction (FPF) can be treated as the gures of merit (FOMs). As the results will show, a combination of the SLO and LROC / EROC curves can determine the configuration that has the most estimation/detection information and thus is a useful method for assessing cardiac SPECT systems.

Lee, Chih-Jie

63

The use of electrical cardiometry for continuous cardiac output monitoring in preterm neonates: a validation study.  

PubMed

Background?Electrical cardiometry (EC) is a continuous noninvasive method for measuring cardiac output (CO), but there are limited data on premature infants. We evaluated the utility of EC monitoring by comparing the results obtained using EC to measurements of CO and systemic blood flow using echocardiography (ECHO). Methods?In this prospective observational study, 40 preterm neonates underwent 108-paired EC and ECHO measurements. Results?There were correlations between EC-CO and left ventricular output (LVO, p?output (RVO, p?

Song, R; Rich, W; Kim, J H; Finer, N N; Katheria, A C

2014-12-01

64

A fMRI Study of Verbal Working Memory, Cardiac Output, and Ejection Fraction in Elderly Patients with Cardiovascular Disease  

Microsoft Academic Search

Cardiovascular disease (CVD) is associated with cognitive deficits even in the absence of stroke. We examined the relationship\\u000a between cardiac performance, as measured by cardiac output (CO) and ejection fraction (EF), and brain activity during a verbal\\u000a working memory (VWM) task in elderly CVD patients who tend to be at increased risk for vascular cognitive impairments. Seventeen\\u000a patients were recruited

Farzin Irani; Lawrence H. Sweet; Andreana P. Haley; John J. Gunstad; Beth A. Jerskey; Richard C. Mulligan; Angela L. Jefferson; Athena Poppas; Ronald A. Cohen

2009-01-01

65

Improved noninvasive method for measurement of cardiac output and evaluation of left-sided cardiac valve incompetence  

SciTech Connect

A time-saving method was developed to label red blood cells in vitro with /sup 99m/Tc while avoiding centrifugation. After tin incubation, extracellular tin was oxidized by sodium hypochlorite, and EDTA was added for stabilizing the complex prior to /sup 99m/Tc incubation. Labeling yields were 95%, and in vivo decay showed a high stability with a mean biologic half-life of eleven hours. The first-passage radionuclide technique for determination of cardiac output using the above-mentioned tracer was evaluated by using the left ventricle as area-of-interest with individual background correction after complete mixing of the tracer. This technique showed a high level of agreement with invasive methods. By combining this method for measurement of the forward stroke volume with the multigated equilibrium principle for determination of the total left ventricular stroke volume using similar background corrections, an exact evaluation of regurgitation fractions was obtained. In patients with aortic and mitral valve disease the noninvasive radionuclide technique gave similar but probably more accurate results as compared with contrast aortography and ventriculography. The radionuclide technique may be suitable for monitoring and selecting patients for surgical treatment.

Kelbaek, H.

1989-05-01

66

Effect of prednisolone treatment on selected respiratory parameters and cardiac output in prematurely delivered neonatal lambs.  

PubMed Central

Lambs were delivered by hysterotomy on days 142 and 143 postcoitum and were assigned to either a control group or a prednisolone-treated group (10 mg/kg daily for four days). On days 1 through 3 of life erythrocyte 2,3-diphosphoglycerate values were significantly increased in the treated group. Prednisolone treatment did not result in significantly increased P50 values. Mean plasma corticoid values in the control group decreased gradually postpartum. The prednisolone-treated lambs compared to the control lambs had depressed corticoid values, differing significantly on day 4. Body weight gains were significantly depressed by treatment and this effect lasted beyond the treatment period. On day 1 of life (24 hours postinitial treatment) oxygen consumption and cardiac output were significantly elevated in the treated group. PMID:647453

Thompson, F N; van Kampen, M; Culver, D H

1978-01-01

67

Low Cardiac Output Secondary to a Malpositioned Umbilical Venous Catheter: Value of Targeted Neonatal Echocardiography  

PubMed Central

Systemic hypotension is common in very low birthweight preterm infants but the nature of the precipitating cause may be unclear. Targeted neonatal echocardiography (TnEcho) is being increasingly used to support hemodynamic decisions in the neonatal intensive care unit (NICU), including identifying impairments in the transitional circulation of preterm infants, providing timely re-evaluation after institution of therapies and evaluating the placement of indwelling catheters. We present a case of a preterm infant with systemic hypotension and low cardiac output secondary to a large transatrial shunt induced by a malpositioned umbilical venous catheter. Repositioning of the line led to resolution of the hemodynamic disturbance and clinical instability, highlighting the utility of TnEcho in the NICU. PMID:25032055

Weisz, Dany E.; Poon, Wei Bing; James, Andrew; McNamara, Patrick J.

2014-01-01

68

Management of perioperative low cardiac output state without extracorporeal life support: What is feasible?  

PubMed Central

A transient and reversible reduction in cardiac output–low cardiac output state (LCOS) often occurs following surgery for congenital heart disease. Inappropriately managed LCOS is a risk factor for increased morbidity and death. LCOS may occasionally be progressive and refractory needing a period of “myocardial rest” with extracorporeal life support (ECLS). ECLS is currently considered a routine tool available for rapid deployment in most industrialized countries. Accumulated experience and refinements in technology have led to improving survivals – discharge survivals of 35%–50%, with almost 100% survival in select groups on elective left ventricular assist device. Thus, there is an increasing trend to initiate ECLS “early or electively in the operating room” in high-risk patients. India has a huge potential need for ECLS given the large number of infants presenting late with preexisting ventricular dysfunction or in circulatory collapse. ECLS is an expensive and resource consuming treatment modality and is not a viable therapeutic option in our country. The purpose of this paper is to reiterate an anticipatory, proactive approach to LCOS: (1) methods for early detection of evolving LCOS and (2) timely initiation of individualized therapy. This paper also explores what is feasible with the refinement of “simple, conventional, inexpensive strategies” for the management of LCOS. Therapy for LCOS should be multimodal based on the type of circulation and physiology. Our approach to LCOS includes: (1) intraoperative strategies, (2) aggressive afterload reduction, (3) lusitropy, (4) exclusion of structural defects, (5) harnessing cardiopulmonary interactions, and (6) addressing metabolic and endocrine abnormalities. We have achieved a discharge survival rate of greater than 97% with these simple methods. PMID:21234194

Kumar, Girish; Iyer, Parvathi U

2010-01-01

69

Age and sex influence the balance between maximal cardiac output and peripheral vascular reserve.  

PubMed

We evaluated the influence of age and sex on the relationship between central and peripheral vasodilatory capacity. Healthy men (19 younger, 12 older) and women (17 younger, 17 older) performed treadmill and knee extensor exercise to fatigue on separate days while maximal cardiac output (Q, acetylene uptake) and peak femoral blood flow (FBF, Doppler ultrasound) were measured, respectively. Maximal Q was reduced with age similarly in men (Y: 23.6 +/- 2.7 vs. O: 17.4 +/- 3.5 l/min; P < 0.05) and women (Y: 17.7 +/- 1.9 vs. O: 12.3 +/- 1.6 l/min; P < 0.05). Peak FBF was similar between younger (Y) and older (O) men (Y: 2.1 +/- 0.5 vs. O: 2.2 +/- 0.7 l/min) but was lower in older women compared with younger women (Y: 1.9 +/- 0.4 vs. O: 1.4 +/- 0.4 l/min; P < 0.05). Maximal Q was positively correlated with peak FBF in men (Y: r = 0.55, O: r = 0.74; P < 0.05) but not in women (Y: r = 0.34, O: r = 0.10). Normalization of cardiac output to appendicular muscle mass and peak FBF to quadriceps mass reduced the correlation between these variables in younger men (r = 0.30), but the significant association remained in older men (r = 0.68; P < 0.05), with no change in women. These data suggest that 1) aerobic capacity is associated with peripheral vascular reserve in men but not women, and 2) aging is accompanied by a more pronounced sex difference in this relationship. PMID:19959767

Ridout, Samuel J; Parker, Beth A; Smithmyer, Sandra L; Gonzales, Joaquin U; Beck, Kenneth C; Proctor, David N

2010-03-01

70

A case series of real-time hemodynamic assessment of high output heart failure as a complication of arteriovenous access in dialysis patients.  

PubMed

Congestive heart failure (CHF) is an important source of morbidity and mortality in end-stage renal disease patients. Although CHF is commonly associated with low cardiac output (CO), it may also occur in high CO states. Multiple conditions are associated with increased CO including congenital or acquired arteriovenous fistulae or arteriovenous grafts. Increased CO resulting from permanent AV access in dialysis patients has been shown to induce structural and functional cardiac changes, including the development of eccentric left ventricle hypertrophy. Often, the diagnosis of high output heart failure requires invasive right heart monitoring in the acute care setting such as a medical or cardiac intensive care unit. The diagnosis of an arteriovenous access causing high output heart failure is usually confirmed after the access is ligated surgically. We present for the first time, a case for real-time hemodynamic assessment of high output heart failure due to AV access by interventional nephrology in the cardiac catheterization suite. PMID:24673654

Singh, Sarguni; Elramah, Mohsen; Allana, Salman S; Babcock, Michael; Keevil, Jon G; Johnson, Maryl R; Yevzlin, Alexander S; Chan, Micah R

2014-11-01

71

Non-invasive beat-to-beat cardiac output monitoring by an improved method of transthoracic bioimpedance measurement  

Microsoft Academic Search

The report describes a method of impedance cardiography using an improved estimate of thoracic volume. The formulas and their implementation in hardware and software are explained and new shortband electrodes are described which generate a good homogeneous thoracic field. Examples of stroke volume and cardiac output curves underline the capabilities of the monitoring system “Task Force® Monitor”. In several experiments,

J. Fortin; W. Habenbacher; A. Heller; A. Hacker; R. Grüllenbergera; J. Innerhofer; H. Passath; Ch. Wagner; G. Haitchi; D. Flotzinger; R. Pacher; P. Wach

2006-01-01

72

Cardiac output and shunt during voluntary activity at different temperatures in the turtle, Trachemys scripta.  

PubMed

Red-eared slider turtles (Trachemys scripta) were chronically instrumented with blood flow probes for a long-term study of voluntary behavior in an enriched laboratory setting. Cardiovascular measures consisting of total cardiac output (Q(tot)), pulmonary blood flow (Q(pul)), systemic blood flow (Q(sys)), net cardiac shunt (Q(shunt)), heart rate (HR), and stroke volume (SV) were obtained during spontaneous activity at a constant body temperature (Tb=2 degrees C) and at unstable (variable) T(b)'s ranging from 19 degrees to 37 degrees C. The effects of temperature and activity differed between the pulmonary and systemic circuits, with increases in Q(sys) due to HR alone, while both HR and SV contributed to gains in Q(pul). At stable 20 degrees C, cardiovascular responses during diving, submerged swimming, and walking were qualitatively similar, and increases in Q(tot) during activity ( approximately 2 x resting levels) were due to greater gains in Q(pul) than Q(sys). At unstable T(b)'s and in general, net Q(shunt) while active depended on the integration of individual physiological influences such as heating, cooling, and initial behavioral state acting on the cardiovascular system. During activity, net left-to-right (L-R) shunts predominated at constant T(b) of 20 degrees C (mean shunt fraction approximately 30%-40%), while both net L-R and right-to-left (R-L) shunts of varying size were found at unstable T(b)'s (19 degrees - 37 degrees C). PMID:14671716

Krosniunas, Egle H; Hicks, James W

2003-01-01

73

Cardiac Output is Not a Significant Source of Low Frequency Mean Arterial Pressure Variability  

PubMed Central

Spontaneous mean arterial pressure (MAP) variability may be mainly due to fluctuations in cardiac output (CO) and total peripheral resistance (TPR). While high frequency (HF ~ 0.25 Hz) oscillations in MAP are ultimately driven by respiration, the source of low frequency (LF ~ 0.1 Hz) fluctuations has not been fully elucidated. It is known that CO buffers these oscillations, but there is no evidence on its potential role in also generating them. The main goal was to determine whether CO is a source of LF variability in MAP. Six dogs were chronically instrumented to obtain beat-to-beat measurements of CO and MAP while the dogs were fully awake and at rest. A causal dynamic model was identified to relate the fluctuations in CO to MAP. The model was then used to predict the MAP fluctuations from the CO fluctuations. The CO fluctuations were able to predict about 70% of the MAP oscillations in the HF band but showed no predictive value in the LF band. Hence, respiration induces CO fluctuations in the HF band that, in turn, cause MAP oscillations, while TPR fluctuations appear to be the dominant mediator of LF fluctuations of MAP. CO is not a significant source of these oscillations, and it may only be responsible for dampening them, likely through the baroreflex. PMID:23969898

Aletti, F; Hammond, RL; Sala-Mercado, JA; Chen, X; O'Leary, DS; Baselli, G; Mukkamala, R

2013-01-01

74

Foetal cardiac function: assessing new technologies.  

PubMed

Assessment of foetal cardiac function is more challenging than in the adult, in whom emerging technologies are tested. The postnatal cardio-respiratory interaction is replaced by the cardio-placental circulation and impedance of the brain, and distal vascular beds play an important role in modulating flow to enable its redistribution in the foetal body. Prenatal specialists, comprising obstetricians and cardiologists, have tested a variety of traditional methodologies, as well as non-Doppler offline ultrasound methods in the foetus. This article reviews the development of techniques, outlines their use, and draws attention to pitfalls in adapting technologies validated in the adult heart to the small, fast beating, remote, and largely ungated foetal heart. PMID:25266927

Gardiner, Helena M

2014-10-01

75

Cardiac output and contractility indices: establishing a standard in response to low-to-moderate level exercise in healthy men.  

PubMed

Measurement by impedance cardiography (ZCG) of cardiac output and contractility indices during exercise is a recent addition to exercise testing of the cardiac patient. To provide a needed standard of normal responses to exercise at integrals of resting oxygen consumption (METS), 10 healthy men were tested. Basal oxygen consumption (1MET) under standardized conditions was measured by mass spectrometry. Over several days the subjects were exercised on a treadmill at 2METS through 6METS with monitoring of heart rate, electrocardiogram, oxygen consumption per minute (VO2) and ZCG. The exercise routine was then repeated to look for test-retest effect. Values closely approximating presently accepted basal oxygen consumptions were achieved under these standardized but practical conditions. Cardiac output during sitting, fully supported rest was slightly higher than that at 2METS on treadmill owing to higher stroke volume. From 2METS through 6METS the curvilinear mean heart rate and stroke volume were mirror images, producing a linear increase in mean cardiac output which at 6METS was 145% of basal and 160% of the 2MET value, while the contractility index increased to 217% of basal. Comparison of the 2 trials revealed no significant test-retest effect. PMID:518263

Mancini, R; Kottke, F J; Patterson, R; Kubicek, W; Olson, M

1979-12-01

76

Health insurance and outcomes: comprehensive assessment of health system outputs.  

PubMed

Outcomes analysis in health care has historically meant the examination of clinical results of inpatient hospitalization. In response to climbing health care and health insurance costs, the organization of health care providers, the location of service delivery and reimbursement mechanisms have changed. As the health care industry changes, so too must the definition of outcomes. This article presents a conceptual framework for the analysis of health outcomes as health industry outputs, with an emphasis on the ways in which such outputs are being assessed and improved. PMID:10116955

Perkins, N A

1991-01-01

77

Arterial pressure-based cardiac output monitoring: a multicenter validation of the third-generation software in septic patients  

Microsoft Academic Search

Purpose  Second-generation FloTrac software has been shown to reliably measure cardiac output (CO) in cardiac surgical patients. However,\\u000a concerns have been raised regarding its accuracy in vasoplegic states. The aim of the present multicenter study was to investigate\\u000a the accuracy of the third-generation software in patients with sepsis, particularly when total systemic vascular resistance\\u000a (TSVR) is low.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Fifty-eight septic patients were

Daniel De Backer; Gernot Marx; Andrew Tan; Christopher Junker; Marc Van Nuffelen; Lars Hüter; Willy Ching; Frédéric Michard; Jean-Louis Vincent

2011-01-01

78

Assessment of cardiac function using multidetector row computed tomography.  

PubMed

In patients with suspected or documented heart disease, a precise quantitative and qualitative assessment of cardiac function is critical for clinical diagnosis, risk stratification, management and prognosis. Cardiac CT is increasingly being used in diagnosis of coronary artery disease. Initially multi-detector row computed tomography (MDCT) was used chiefly for detecting coronary artery stenosis and assessment of cardiac morphology. Electron beam computed tomography has been shown to provide a highly accurate ejection fraction (+/-1%), with 50 ms image acquisition per image. Retrospective electrocardiographic gating allows for image reconstruction in any phase of the cardiac cycle. Thus, end systolic and end diastolic images can be produced to assess ventricular volumes and function. Despite lower temporal resolution than electron beam computed tomography, the ability of MDCT to assess ejection fraction is preserved. In the assessment of cardiac function, MDCT has been shown to be in good agreement with echocardiography, cineventriculography, single photon emission computed tomography and magnetic resonance imaging. The fast technical development of scanner hardware along with multisegmental image reconstruction has led to rapid improvement of spatial and temporal resolution and significantly faster cardiac scans. The same data that is acquired for MDCT angiography can also be used for evaluation of cardiac function. Considering contrast media application, radiation exposure, and limited temporal resolution, MDCT solely for analysis of cardiac function parameters seems not reasonable at the present time. However, because the data is already obtained during coronary evaluation, the combination of noninvasive coronary artery imaging and assessment of cardiac function with MDCT is a suitable approach to a conclusive cardiac workup in patients with suspected coronary artery disease. MDCT seems suitable for assessment of cardiac function by MDCT when results are held in comparison to magnetic resonance imaging as the reference standard. Given the radiation dose and contrast requirement, referring a patient to MDCT only for evaluation of function is not warranted, but rather adds important clinical information to the already acquired data during retrospective triggering for MDCT angiography. PMID:16845283

Orakzai, Sarwar H; Orakzai, Raza H; Nasir, Khurram; Budoff, Matthew J

2006-01-01

79

Increased cardiac output contributes to the development of chronic intermittent hypoxia-induced hypertension.  

PubMed

Chronic intermittent hypoxia (CIH) in animal models has been shown to result in hypertension and elevation of sympathetic nervous system activity. Sympathetically mediated vasoconstriction is believed to be the primary mechanism underpinning CIH-induced hypertension; however, the potential contribution of the heart is largely overlooked. We sought to determine the contribution of cardiac output (CO) and lumbar sympathetic control of the hindlimb circulation to CIH-induced hypertension. Male Wistar rats (n = 64) were exposed to 2 weeks of CIH [cycles of 90 s hypoxia (5% O2 nadir) and 210 s normoxia] or normoxia for 8 h day(-1). Under urethane anaesthesia, CIH-treated animals developed hypertension (81.4 ± 2.2 versus 91.6 ± 2.4 mmHg; P < 0.001), tachycardia (397 ± 8 versus 445 ± 7 beats min(-1); P < 0.001) and an increased haematocrit (42.4 ± 0.4 versus 45.0 ± 0.4%; P < 0.001). Echocardiography revealed that CIH exposure increased the CO [19.3 ± 1.7 versus 25.8 ± 2.6 ml min(-1) (100 g)(-1); P = 0.027] with no change in total peripheral resistance (4.93 ± 0.49 versus 4.17 ± 0.34 mmHg ml(-1) min(-1); P = 0.123). Sympathetic ganglionic blockade revealed that sympathetic control over blood pressure was not different (-27.7 ± 1.6 versus -32.3 ± 2.9 mmHg; P = 0.095), and no chronic vasoconstriction was found in the hindlimb circulation of CIH-treated animals (39.4 ± 2.5 versus 38.0 ± 2.4 ?l min(-1) mmHg(-1); P = 0.336). Lumbar sympathetic control over the hindlimb circulation was unchanged in CIH-treated animals (P = 0.761), although hindlimb arterial sympathetic density was increased (P = 0.012) and vascular sensitivity to phenylephrine was blunted (P = 0.049). We conclude that increased CO is sufficient to explain the development of CIH-induced hypertension, which may be an early adaptive response to raise O2 flow. We propose that sustained elevated cardiac work may ultimately lead to heart failure. PMID:25063839

Lucking, Eric F; O'Halloran, Ken D; Jones, James F X

2014-10-01

80

Environmental risk assessments for transgenic crops producing output trait enzymes  

PubMed Central

The environmental risks from cultivating crops producing output trait enzymes can be rigorously assessed by testing conservative risk hypotheses of no harm to endpoints such as the abundance of wildlife, crop yield and the rate of degradation of crop residues in soil. These hypotheses can be tested with data from many sources, including evaluations of the agronomic performance and nutritional quality of the crop made during product development, and information from the scientific literature on the mode-of-action, taxonomic distribution and environmental fate of the enzyme. Few, if any, specific ecotoxicology or environmental fate studies are needed. The effective use of existing data means that regulatory decision-making, to which an environmental risk assessment provides essential information, is not unnecessarily complicated by evaluation of large amounts of new data that provide negligible improvement in the characterization of risk, and that may delay environmental benefits offered by transgenic crops containing output trait enzymes. PMID:19924556

Tuttle, Ann; Shore, Scott; Stone, Terry

2009-01-01

81

Monitoring non-invasive cardiac output and stroke volume during experimental human hypovolaemia and resuscitation  

PubMed Central

Background Multiple methods for non-invasive measurement of cardiac output (CO) and stroke volume (SV) exist. Their comparative capabilities are not clearly established. Methods Healthy human subjects (n=21) underwent central hypovolaemia through progressive lower body negative pressure (LBNP) until the onset of presyncope, followed by termination of LBNP, to simulate complete resuscitation. Measurement methods were electrical bioimpedance (EBI) of the thorax and three measurements of CO and SV derived from the arterial blood pressure (ABP) waveform: the Modelflow (MF) method, the long-time interval (LTI) method, and pulse pressure (PP). We computed areas under receiver-operating characteristic curves (ROC AUCs) for the investigational metrics, to determine how well they discriminated between every combination of LBNP levels. Results LTI and EBI yielded similar reductions in SV during progressive hypovolaemia and resuscitation (correlation coefficient 0.83) with ROC AUCs for distinguishing major LBNP (?60 mm Hg) vs resuscitation (0 mm Hg) of 0.98 and 0.99, respectively. MF yielded very similar reductions and ROC AUCs during progressive hypovolaemia, but after resuscitation, MF-CO did not return to baseline, yielding lower ROC AUCs (?ROC AUC range, ?0.18 to ?0.26, P<0.01). PP declined during hypovolaemia but tended to be an inferior indicator of specific LBNP levels, and PP did not recover during resuscitation, yielding lower ROC curves (P<0.01). Conclusions LTI, EBI, and MF were able to track progressive hypovolaemia. PP decreased during hypovolaemia but its magnitude of reduction underestimated reductions in SV. PP and MF were inferior for the identification of resuscitation. PMID:21051492

Reisner, A. T.; Xu, D.; Ryan, K. L.; Convertino, V. A.; Rickards, C. A.; Mukkamala, R.

2011-01-01

82

Carotid baroreflex pressor responses at rest and during exercise: cardiac output vs. regional vasoconstriction.  

PubMed

The arterial baroreflex mediates changes in arterial pressure via reflex changes in cardiac output (CO) and regional vascular conductance, and the relative roles may change between rest and exercise and across workloads. Therefore, we quantified the contribution of CO and regional vascular conductances to carotid baroreflex-mediated increases in mean arterial pressure (MAP) at rest and during mild to heavy treadmill exercise (3.2 kph; 6.4 kph, 10% grade; and 8 kph, 15% grade). Dogs (n = 8) were chronically instrumented to measure changes in MAP, CO, hindlimb vascular conductance, and renal vascular conductance in response to bilateral carotid occlusion (BCO). At rest and at each workload, BCO caused similar increases in MAP (average 35 +/- 2 mmHg). In response to BCO, neither at rest nor at any workload were there significant increases in CO; therefore, the pressor response occurred via peripheral vasoconstriction. At rest, 10.7 +/- 1.4% of the rise in MAP was due to vasoconstriction in the hindlimb, whereas 4.0 +/- 0.7% was due to renal vasoconstriction. Linear regression analysis revealed that, with increasing workloads, relative contributions of the hindlimb increased and those of the kidney decreased. At the highest workload, the decrease in hindlimb vascular conductance contributed 24.3 +/- 3.4% to the pressor response, whereas the renal contribution decreased to only 1.6 +/- 0.3%. We conclude that the pressor response during BCO was mediated solely by peripheral vasoconstriction. As workload increases, a progressively larger fraction of the pressor response is mediated via vasoconstriction in active skeletal muscle and the contribution of vasoconstriction in inactive beds (e.g., renal) becomes progressively smaller. PMID:11158962

Collins, H L; Augustyniak, R A; Ansorge, E J; O'Leary, D S

2001-02-01

83

Does left ventricular tissue Doppler peak systolic velocity (Sm) reflect cardiac output in the critically ill?  

PubMed

Cardiac output (CO) is dependent on a number of factors, in particular, the systolic function of the heart. Tissue Doppler (TD) is a modality in echocardiography that measures myocardial velocity and is related to contractility. TD can therefore be used to measure the systolic function of the heart. This study sought to establish whether the systolic component of TD can be used to estimate CO in critically ill patients. Retrospective data was obtained from a total of 80 patients: 29 patients with a normal echocardiogram, and 51 intensive care unit patients; 28 septic and 23 with heart failure. The mean TD peak systolic velocity (Sm) was significantly lower in the heart failure patients (P <0.05) compared to both normal and septic group. The mean CO was significantly higher in septic patients when compared to heart failure patients. A mild to moderate positive correlation was found between Sm and CO in the heart failure group and with all patients combined (r2=0.19, P <0.001). Subsequent analysis of Sm versus stroke volume again showed a mild positive correlation in the heart failure group and combined results (r2=0.18, P <0.001). Sm was weakly correlated to heart rate only in the normal group but not in the combined cohort. Our data confirms a weak to moderate correlation between Sm and CO, probably resulting from a positive correlation of Sm and stroke volume. This correlation is not strong enough to support the use of an individual's Sm to estimate CO in intensive care patients. PMID:23808508

Golowenko, A R; Nalos, M; Huang, S J

2013-07-01

84

Changes in cardiac output during swimming and aquatic hypoxia in the air-breathing Pacific tarpon.  

PubMed

Pacific tarpon (Megalops cyprinoides) use a modified gas bladder as an air-breathing organ (ABO). We examined changes in cardiac output (V(b)) associated with increases in air-breathing that accompany exercise and aquatic hypoxia. Juvenile (0.49 kg) and adult (1.21 kg) tarpon were allowed to recover in a swim flume at 27 degrees C after being instrumented with a Doppler flow probe around the ventral aorta to monitor V(b) and with a fibre-optic oxygen sensor in the ABO to monitor air-breathing frequency. Under normoxic conditions and in both juveniles and adults, routine air-breathing frequency was 0.03 breaths min(-1) and V(b) was about 15 mL min(-1) kg(-1). Normoxic exercise (swimming at about 1.1 body lengths s(-1)) increased air-breathing frequency by 8-fold in both groups (reaching 0.23 breaths min(-1)) and increased V(b) by 3-fold for juveniles and 2-fold for adults. Hypoxic exposure (2 kPa O2) at rest increased air-breathing frequency 19-fold (to around 0.53 breaths min(-1)) in both groups, and while V(b) again increased 3-fold in resting juvenile fish, V(b) was unchanged in resting adult fish. Exercise in hypoxia increased air-breathing frequency 35-fold (to 0.95 breaths min(-1)) in comparison with resting normoxic fish. While juvenile fish increased V(b) nearly 2-fold with exercise in hypoxia, adult fish maintained the same V(b) irrespective of exercise state and became agitated in comparison. These results imply that air-breathing during exercise and hypoxia can benefit oxygen delivery, but to differing degrees in juvenile and adult tarpon. We discuss this difference in the context of myocardial oxygen supply. PMID:17869150

Clark, T D; Seymour, R S; Christian, K; Wells, R M G; Baldwin, J; Farrell, A P

2007-11-01

85

Subject-specific Model Estimation of Cardiac Output and Blood Volume During Hemorrhage  

PubMed Central

We have developed a novel method for estimating subject-specific hemodynamics during hemorrhage. First, a mathematical model representing a closed-loop circulation and baroreceptor feedback system was parameterized to match the baseline physiology of individual experimental subjects by fitting model results to 1 min of pre-injury data. This automated parameterization process matched pre-injury measurements within 1.4 ± 1.3% SD. Tuned parameters were then used in similar open-loop models to simulate dynamics post-injury. Cardiac output (CO) estimates were obtained continuously using post-injury measurements of arterial blood pressure (ABP) and heart rate (HR) as inputs to the first open-loop model. Secondarily, total blood volume (TBV) estimates were obtained by summing the blood volumes in all the circulatory segments of a second open-loop model that used measured CO as an additional input. We validated the estimation method by comparing model CO results to flowprobe measurements in 14 pigs. Overall, CO estimates had a Bland-Altman bias of ?0.30 l/min with upper and lower limits of agreement 0.80 and ?1.40 l/min. The negative bias is likely due to overestimation of the peripheral resistance response to hemorrhage. There was no reference measurement of TBV; however, the estimates appeared reasonable and clearly predicted survival versus death during the post-hemorrhage period. Both open-loop models ran in real time on a computer with a 2.4 GHz processor, and their clinical applicability in emergency care scenarios is discussed. PMID:17846886

Neal, Maxwell Lewis; Bassingthwaighte, James B.

2010-01-01

86

Environmental risk assessments for transgenic crops producing output trait enzymes  

Microsoft Academic Search

The environmental risks from cultivating crops producing output trait enzymes can be rigorously assessed by testing conservative\\u000a risk hypotheses of no harm to endpoints such as the abundance of wildlife, crop yield and the rate of degradation of crop\\u000a residues in soil. These hypotheses can be tested with data from many sources, including evaluations of the agronomic performance\\u000a and nutritional

Alan Raybould; Ann Tuttle; Scott Shore; Terry Stone

2010-01-01

87

Cardiac Assessment in Duchenne and Becker Muscular Dystrophies  

Microsoft Academic Search

Background: Cardiac problems are common and are a major cause of death in both Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). Early diagnosis and proper management are very important for prolonging life expectancy, improving mobility and the quality of life in dystrophinopathic patients. The object of this study was to assess the cardiac dysfunction in dystrophinopathic patients. Methods:

Tae-Jin Song; Young-Chul Choi

88

Pharmacokinetic assessment of sufentanil in cardiac surgery.  

PubMed

Plasma monitoring and pharmacokinetic assessment are important tools used in therapeutic control. Sufentanil is responsible for the hemodynamic stabilization of patients, providing better suppression of the neuroendocrine response compared to its analogue fentanyl. This study aims to use the plasma monitoring of sufentanil in patients undergoing cardiac surgery with extracorporeal circulation (ECC, group 1) or without ECC (group 2) to assess the pharmacokinetics of the compound.The 42 patients in this study received 0.5 ?g/kg of sufentanil through bolus injection followed by a maintenance infusion of 0.5 ?g/kg.h. Serial blood samples were collected during the post induction intraoperative period and during the postoperative period until 36 h after sufentanil administration. The plasma concentrations were determined by a validated method utilizing liquid chromatography coupled to mass spectrometry. The pharmacokinetic modeling was performed using a 3-compartment model fit.The surgical patients included in the protocol were adults of both genders, with 30 patients in the ECC group and 12 in the group without ECC. The plasma concentrations obtained were significantly different between the 2 groups. During the extracorporeal circulation procedure, intense fluctuations were observed in the sufentanil plasma concentrations. Compared with the results of group 2, the ECC procedure reduced the terminal or gamma half-life from 36.35 ± 6.37 h to 23.25 ± 2.75 h in group 1. In addition, the ECC procedure promoted higher fluctuations in the sufentanil plasma concentrations without causing alterations in the area under the curve, distribution volume, clearance or the distributional (alpha) and rapid elimination (beta) half-lives (t1/2? and t1/2?, respectively). PMID:23780500

Manfio, J L; Santos, L M; Carmona, M J C; Dos Santos, M B; Santos, S Rcj

2013-10-01

89

Effect of analyzer on determination of mixed venous PCO2 and cardiac output during exercise.  

PubMed

Cardiac output (CO) during exercise can be determined noninvasively by using the indirect Fick CO2-rebreathing technique. CO2 measurements for this technique are usually performed with an infrared analyzer (IA) or mass spectrometer (MS). However, IA CO2 measurements are susceptible to underreading in the face of high O2 concentrations because of collision broadening. We compared an IA (Ametek model CD-3A) with a MS (Marquette model MGA-1100) to see the effect this would have on mixed venous PCO2 (PVCO2) and CO measurements. After calibration with room air and a gas mixture of 5% CO2-12% O2-83% N2, both devices were tested with three different gas mixtures of CO2 in O2. For each gas mixture, IA gave lower CO2 values than did the MS (4.1% CO2: IA, 3.85 +/- 0.01% and MS, 4.13 +/- 0.01%; 9.2% CO2: IA, 8.44 +/- 0.07% and MS, 9.19 +/- 0.01%; 13.8% CO2: IA, 12.57 +/- 0.15% and MS, 13.82 +/- 0.01%). Warming and humidifying the gases did not alter the results. The IA gave lower values than did the MS for eight other medical gases in lower concentrations of O2 (40-50%). Equilibrium and exponential rebreathing procedures were performed. Values determined by the IA were > 10% higher than those determined by the MS for both rebreathing methods. We conclude that all IAs must be checked for collision broadening if they are to be used in environments where the concentration of O2 is > 21%. If collision broadening is present, then either a special high O2-CO2 calibration curve must be constructed, or the IA should not be used for both arterial PCO2 and PVCO2 estimates because it may produce erroneously low PVCO2 values, with resultant overestimation of CO. PMID:8567499

Hornby, L; Coates, A L; Lands, L C

1995-09-01

90

Scintigraphic assessment of heterotopic cardiac transplants  

SciTech Connect

Patients receiving heterotopic (''piggyback'') cardiac transplants, when the patient's own and transplanted donor hearts are connected in parallel, present special problems in determining their relative contributions to total cardiac function. Three patients who had transplants because of intractable heart failure were studied using first pass and gated equilibrium technetium-99m-labeled blood pool scintigraphy. In one patient, thallium-201 myocardial perfusion scans were obtained. These nuclear cardiology techniques provided anatomic and functional information noninvasively that proved helpful in patient management.

Wilson, M.A.; Kahn, D.R.

1981-01-01

91

Scintigraphic assessment of heterotopic cardiac transplants  

SciTech Connect

Patients receiving heterotopic (piggyback) cardiac transplants, when the patient's own and transplanted donor hearts are connected in parallel, present special problems in determining their relative contributions to total cardiac function. Three patients who had transplants because of intractable heart failure were studied using first pass and gated equilibrium technetium-99m-labeled blood pool scintigraphy. In one patient, thallium-201 myocardial perfusion scans were obtained. These nuclearcardiology techniques provided anatomic and functional information noninvasively that proved helpful in patient management.

Wilson, M.A.; Kahn, D.R.

1981-10-01

92

Preoperative cardiac assessment in patients undergoing major vascular surgery.  

PubMed

The aim of this study was to evaluate the effectiveness of a preoperative standardized cardiac assessment in patients undergoing major vascular surgery. From January 2005 to December 2006, 1446 elective interventions for major vascular diseases (carotid stenosis, CS; abdominal aortic aneurysm, AAA; peripheral arterial obstructive disease, PAOD) were performed; 1090 out of these patients underwent preoperative diagnostic assessment on an outpatient basis. Thirty-day results in terms of cardiac mortality and morbidity rates were recorded. Patients suffered from a CS in 578 cases (53%), an AAA in 303 cases (27.8%) and a PAOD in 209 cases (19.2%). Four hundred thirty-two patients (39.6%) underwent further evaluation of cardiac functional capacity with non-invasive stress testing. Sixteen patients were successfully treated prior to vascular surgery. Thirty-day cardiac mortality and morbidity rates were 0.2% and 3.9%, respectively. A positive preoperative non-invasive stress testing did not affect 30-day cardiac outcomes. In conclusion, the use of an accurate preoperative cardiac assessment allowed us to obtain satisfactory perioperative results in patients undergoing major vascular surgery. Routine preoperative evaluation with non-invasive stress testing did not seem to improve perioperative cardiac results. PMID:21742935

Troisi, Nicola; Pulli, Raffaele; Dorigo, Walter; Lo Sapio, Patrizia; Pratesi, Carlo

2011-08-01

93

Derivation of cardiac output and alveolar ventilation rate based on energy expenditure measurements in healthy males and females.  

PubMed

Physiologically based pharmacokinetic modeling and occupational exposure assessment studies often use minute ventilation rates (VE), alveolar ventilation rates (VA) and cardiac outputs (Q) that are not reflective of the physiological variations encountered during the aggregate daytime activities of individuals from childhood to adulthood. These variations of VE, VA and Q values were determined for healthy normal-weight individuals aged 5-96?years by using two types of published individual data that were measured in the same subjects (n?=?902), namely indirect calorimetry measurements and the disappearance rates of oral doses of deuterium (²H) and heavy-oxygen (¹?O) in urine monitored by gas-isotope-ratio mass spectrometry. Arteriovenous oxygen content differences (0.051-0.082?ml of O? consumed ml?¹ of blood) and ratios of the physiological dead space to the tidal volume (0.232-0.419) were determined for oxygen consumption rates (0.157-0.806?l min?¹) required by minute energy expenditures ranging from 0.76 to 3.91?kcal min?¹. Generally higher values for the 2.5th up to the 99th percentile for VE (0.132-0.774?l kg?¹ min?¹, 4.42-21.69?l m?² min?¹), VA (0.093-0.553?l kg?¹ min?¹, 3.09-15.53?l m?² min?¹), Q (0.065-0.330?l kg?¹ min?¹, 2.17 to 9.46?l m?² min?¹) and ventilation-perfusion ratios (1.12-2.16) were found in children and teenagers aged 5-<16.5?years compared with older individuals. The distributions of cardiopulmonary parameters developed in this study should be useful in facilitating a scientifically sound characterization of the inter-individual differences in the uptake and health risks of lipophilic air pollutants, particularly as they relate to younger children. PMID:21365669

Brochu, Pierre; Brodeur, Jules; Krishnan, Kannan

2012-08-01

94

Femoral Blood Flow and Cardiac Output During Blood Flow Restricted Leg Press Exercise  

NASA Technical Reports Server (NTRS)

Low load blood flow restricted resistance exercise (LBFR) causes muscle hypertrophy that may be stimulated by the local ischemic environment created by the cuff pressure. However, local blood flow (BF) during such exercise is not well understood. PURPOSE: To characterize femoral artery BF and cardiac output (CO) during leg press exercise (LP) performed at a high load (HL) and low load (LL) with different levels of cuff pressure. METHODS: Eleven subjects (men/women 4/7, age 31.4+/-12.8 y, weight 68.9+/-13.2 kg, mean+/-SD) performed 3 sets of supine left LP to fatigue with 90 s of rest in 4 conditions: HL (%1-RM/cuff pressure: 80%/0); LL (20%/0); LBFR(sub DBP) (20%/1.3 x diastolic blood pressure, BP); LBFR(sub SBP) (20%/1.3 x supine systolic BP). The cuff remained inflated throughout the LBFR exercise sessions. Artery diameter, velocity time integral (VTI), and stroke volume (SV) were measured using Doppler ultrasound at rest and immediately after each set of exercise. Heart rate (HR) was monitored using a 3-lead ECG. BF was calculated as VTI x vessel cross-sectional area. CO was calculated as HR x SV. The data obtained after each set of exercise were averaged and used for analyses. Multi-level modeling was used to determine the effect of exercise condition on dependent variables. Statistical significance was set a priori at p< 0.05. RESULTS: Artery diameter did not change from baseline. BF increased (p<0.05) after exercise in each condition except LBFR(sub SBP) in the order of HL (12.73+/-1.42 cm3,mean+/-SE) > LL (9.92+/-0.82 cm3) > LBFR(sub dBP)(6.47+/-0.79 cm3) > LBFR(sub SBP) (3.51+/-0.59 cm3). Blunted exercise induced increases occurred in HR, SV, and CO after LBFR compared to HL and LL. HR increased 45% after HL and LL and 28% after LBFR (p<0.05), but SV increased (p<0.05) only after HL. Consequently, the increase (p<0.05) in CO was greater in HL and LL (approximately 3 L/min) than in LBFR (approximately 1 L/min). CONCLUSION: BF during LBFR(sub SBP) was 1/3 of that observed in LL, which supports the hypothesis that local ischemia stimulates the LBFR hypertrophic response. As the cuff did not compress the artery, the ischemia may have occurred because of the blunted rise in CO or because arterial BP cannot overcome the cuff pressure. As LBFR(sub DBP) effectively reduced BF and CO with cuff pressures less than systolic BP, future studies should investigate the hypertrophic potential of LBFR at even lower cuff pressures.

Everett, M. E.; Hackney, K.; Ploutz-Snyder, L.

2011-01-01

95

Design and testing of an MRI-compatible cycle ergometer for non-invasive cardiac assessments during exercise  

PubMed Central

Background Magnetic resonance imaging (MRI) is an important tool for cardiac research, and it is frequently used for resting cardiac assessments. However, research into non-pharmacological stress cardiac evaluation is limited. Methods We aimed to design a portable and relatively inexpensive MRI cycle ergometer capable of continuously measuring pedalling workload while patients exercise to maintain target heart rates. Results We constructed and tested an MRI-compatible cycle ergometer for a 1.5 T MRI scanner. Resting and sub-maximal exercise images (at 110 beats per minute) were successfully obtained in 8 healthy adults. Conclusions The MRI-compatible cycle ergometer constructed by our research group enabled cardiac assessments at fixed heart rates, while continuously recording power output by directly measuring pedal force and crank rotation. PMID:22423637

2012-01-01

96

Assessment of Cardiac Sarcoidosis with Advanced Imaging Modalities  

PubMed Central

Sarcoidosis is a chronic systemic disease of unknown etiology that is characterized by the presence of noncaseating epithelioid granulomas, usually in multiple organs. Several studies have shown that sarcoidosis might be the result of an exaggerated granulomatous reaction after exposure to unidentified antigens in genetically susceptible individuals. Cardiac involvement may occur and lead to an adverse outcome: the heart mechanics will be affected and that causes ventricular failure, and the cardiac electrical system will be disrupted and lead to third degree atrioventricular block, malignant ventricular tachycardia, and sudden cardiac death. Thus, early diagnosis and treatment of this potentially devastating disease is critically important. However, sensitive and accurate imaging modalities have not been established. Recent studies have demonstrated the promising potential of cardiac magnetic resonance imaging (MRI) and 18F-fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET) in the diagnosis and assessment of cardiac sarcoidosis (CS). In this review, we discuss the epidemiology, etiology, histological findings, and clinical features of sarcoidosis. We also introduce advanced imaging including 18F-FDG PET and cardiac MRI as more reliable diagnostic modalities for CS.

Akasaka, Takashi

2014-01-01

97

Effects of Dobutamine on Left Ventricular Performance, Coronary Dynamics, and Distribution of Cardiac Output in Conscious Dogs  

PubMed Central

The effects of dobutamine ([±]-4-[2-[[3-(p-hydroxyphenyl)-1-methyl propyl] amino] ethyl] pyrocatechol hydrochloride), a new synthetic cardioactive sympathomimetic amine, were examined on direct and continuous measurements of left ventricular (LV) diameter (D), pressures (P), velocity of shortening (V), dP/dt, dP/dt/P, arterial pressure, cardiac output, and regional blood flows in the left circumflex coronary, mesenteric, renal, and iliac beds in healthy, conscious dogs. At the highest dose of dobutamine examined, 40 ?g/kg/min, the drug increased dP/dt/P from 65±3 to 128±4 s-1 and isolength velocity from 72±4 to 120±7 mm/s without affecting LV end diastolic D significantly. Mean arterial P rose from 92±2 to 104±3 mm Hg and heart rate from 78±3 to 111±7 beats/min, while LV end systolic D fell from 24.1±1.4 to 19.9±1.8 mm, reflecting a rise in stroke volume from 30±4 to 42±3 ml. Cardiac output rose from 2.41±0.23 to 4.35±0.28 liter/min, while calculated total peripheral resistance declined from 0.042±0.005 to 0.028±0.003 mm Hg/ml/min. The greatest increases in flow and decreases in calculated resistance occurred in the iliac and coronary beds, and the least occurred in the renal bed. Propranolol blocked the inotropic and beta2 dilator responses while vasoconstricting effects mediated by alpha adrenergic stimulation remained in each of the beds studied. When dobutamine was infused after a combination of practolol and phentolamine, dilatation occurred in each of the beds studied. These observations indicate that dobutamine is a potent positive inotropic agent with relatively slight effects on preload, afterload, or heart rate, and thus may be a potentially useful clinical agent. The one property of this drug which is not ideal is its tendency to cause a redistribution of cardiac output favoring the muscular beds at the expense of the kidney and visceral beds. Images PMID:4825224

Vatner, Stephen F.; McRitchie, Robert J.; Braunwald, Eugene

1974-01-01

98

Efficacy and safety of milrinone in preventing low cardiac output syndrome in infants and children after corrective surgery for congenital heart disease  

Microsoft Academic Search

Background—Low cardiac output syndrome (LCOS), affecting up to 25% of neonates and young children after cardiac surgery, contributes to postoperative morbidity and mortality. This study evaluated the efficacy and safety of prophylactic milrinone in pediatric patients at high risk for developing LCOS. Methods and Results—The study was a double-blind, placebo-controlled trial with 3 parallel groups (low dose, 25-g\\/kg bolus over

Timothy M. Hoffman; Gil Wernovsky; Andrew M. Atz

2003-01-01

99

Analysis of interobserver and intraobserver variation of interpretation of the echocardiographic and Doppler flow determination of cardiac output by the mitral orifice method.  

PubMed Central

The variability of the interpretation by two individuals of a combined echocardiographic and Doppler method of calculating output was studied in 30 normal adults. In each subject three separate cardiac cycles were recorded to calculate maximal mitral valve orifice, the ratio of mean to maximal mitral valve leaflet separation, and the mean flow velocity through the mitral valve. The recordings were digitised twice by two independent observers. Estimates of cardiac output ranged from 3.2 to 8.11 1/min. Analysis of variance showed that interobserver and intraobserver variability for these measurements was 5.8% and 6.1% respectively. It is concluded that the reproducibility for interpreting this non-invasive method is adequate for clinical use in adults with cardiac outputs within the normal range. PMID:3707784

Nicolosi, G L; Pungercic, E; Cervesato, E; Modena, L; Zanuttini, D

1986-01-01

100

AN ASSESSMENT OF DATA ON OUTPUT INDUSTRIAL SUB-SECTORS  

E-print Network

on the determination of an appropriate output measure tested against three criteria: its simplicity, its usefulness, preferably standardized physical measures, as opposed to non-physical or economic measures. Specific to be uniformly measured by some standardized physical unit, that unit should serve as the output measure

101

[Influence of cerebral perfusion pressure and cardiac output on brain oxygenation and metabolism].  

PubMed

The article contains results of examination of correlation between systemic hemodynamic and brain oxygenation and metabolism in patients with intracranial hemorrhage. Cardiac index (CI) and cerebral perfusion pressure (CPP) levels were compared to brain oxygenation and metabolism in 8 patients with intracranial hemorrhage (137 measurements). CI alterations didn't influence on PbrO2, glucose level or lactate/pyruvate ratio in the brain interstitial fluid in patients with traumatic brain injury. CPP elevation led to cerebral metabolism improvement. Optimal metabolic state was mentioned in CPP > 80 mm Hg. CPP elevation led to PbrO2 increasing in patients with subarachnoid hemorrhage due to aneurism rupture. This phenomenon can be explained by damage mechanisms of cerebral blood flow autoregulation. In these cases CI elevation was accompanied by worsening of aerobic metabolism in theoretically intact regions and improving it in injured brain regions. PMID:24341044

Titova, Iu V; Petrikov, S S; Solodov, A A; Krylov, V V

2013-01-01

102

Regulatory efforts to assess and improve the quality of pediatric cardiac surgery in New York State  

Microsoft Academic Search

The New York State Department of Health developed a Pediatric Cardiac Surgery Reporting System in 1991 that contains detailed information on demographics, diagnoses, procedures, comorbidities, complications, and discharge information for every pediatric cardiac surgery patient in the state. The Department and the Congenital Cardiac Services Subcommittee of the Department's Cardiac Advisory Committee have used data from this system to assess,

Edward L. Hannan; Kimberly S. Cozzens; Zaza Samadashvili; John N. Morley; Roberta G. Williams; Thomas J. Kulik; Frederick Z. Bierman; Carlos E. Ruiz; George M. Alfieris; John J. Lamberti; Jeffrey P. Gold

103

Quantitative method to assess economic output of climate change  

NASA Astrophysics Data System (ADS)

In this paper, economic output of climate change is picked from the historical data, and a methodology of quantitative predicted economic output of climate change is provided by an economic-climatic model (C-D-C model). A historical reciprocating examination is engaged, using the data of outputs of various crops and total outputs of grain in 8 agricultural areas of China from 1981 to 2000, as well as the meteorological data of 160 observatory stations in China in the same time interval. The results show the methods are reasonable in certain extent and good in application. Finally, meaningful summery is concluded. The authors try to give a way for studying the effect of the future climatic change on economy. The results in economic research are introduced to the global climatic change study.

jieming, C.

2013-12-01

104

Effect of cardiac output on gas exchange in one-lung atelectasis.  

PubMed

To evaluate the effect of administration of dobutamine on gas exchange in patients with one-lung atelectasis during pneumonectomy, ten patients with normal pulmonary function and localized carcinoma of the lung were studied during pulmonary resection. With each patient in the lateral decubitus position, hemodynamic profiles and oxygen transport data were recorded before and after administration of dobutamine at 5 micrograms/kg/min. Patients were ventilated with one-lung anesthesia and administration of 100 percent oxygen. With infusion of dobutamine, the heart rate, cardiac index, and LVSWI significantly increased. Mean arterial pressure increased while PAP fell. Systemic and pulmonary vascular resistance also declined. Arterial oxygenization and delivery improved, while oxygen uptake was unchanged. Pulmonary shunt fraction was significantly reduced. While the mechanism for shunt reduction in our patients is unclear, operative factors may include pulmonary vasodilation with dobutamine inhibition of HPV. The negative impact of reduced HPV may have been lessened by gravitational distribution of blood flow and dobutamine-mediated reduction in PAP in our patients. PMID:2331907

Mathru, M; Dries, D J; Kanuri, D; Blakeman, B; Rao, T

1990-05-01

105

The "systolic volume balance" method for the noninvasive estimation of cardiac output based on pressure wave analysis.  

PubMed

Cardiac output (CO) monitoring is essential for the optimal management of critically ill patients. Several mathematical methods have been proposed for CO estimation based on pressure waveform analysis. Most of them depend on invasive recording of blood pressure and require repeated calibrations, and they suffer from decreased accuracy under specific conditions. A new systolic volume balance (SVB) method, including a simpler empirical form (eSVB), was derived from basic physical principles that govern blood flow and, in particular, a volume balance approach for the conservation of mass ejected into and flowed out of the arterial system during systole. The formulas were validated by a one-dimensional model of the systemic arterial tree. Comparisons of CO estimates between the proposed and previous methods were performed in terms of agreement and accuracy using "real" CO values of the model as a reference. Five hundred and seven different hemodynamic cases were simulated by altering cardiac period, arterial compliance, and resistance. CO could be accurately estimated by the SVB method as follows: CO = C × PP(ao)/(T - P(sm) × T(s)/P(m)) and by the eSVB method as follows: CO = k × C × PP(ao)/T, where C is arterial compliance, PP(ao) is aortic pulse pressure, T is cardiac period, P(sm) is mean systolic pressure, T(s) is systolic duration, P(m) is mean pressure, and k is an empirical coefficient. SVB applied on aortic pressure waves did not require calibration or empirical correction for CO estimation. An empirical coefficient was necessary for brachial pressure wave analysis. The difference of SVB-derived CO from model CO (for brachial waves) was 0.042 ± 0.341 l/min, and the limits of agreement were -0.7 to 0.6 l/min, indicating high accuracy. The intraclass correlation coefficient and root mean square error between estimated and "real" CO were 0.861 and 0.041 l/min, respectively, indicating very good accuracy. eSVB also provided accurate estimation of CO. An in vivo validation study of the proposed methods remains to be conducted. PMID:22427512

Papaioannou, Theodore G; Vardoulis, Orestis; Stergiopulos, Nikos

2012-05-15

106

Non-Invasive Cardiac Output Measurement in Low and Very Low Birth Weight Infants: A Method Comparison  

PubMed Central

Background: Cardiac output (CO) measurement in low (LBW) and very low (VLBW) birth weight infants is difficult. Hitherto, sporadical transthoracic echocardiography (TTE) is the only non-invasive measurement method. Electrical velocimetry (EV) has been evaluated as an alternative in normal weight newborns. Objectives: The study was designed to evaluate if EV could be interchangeable with TTE even in LBW and VLBW infants. Methods: In 28 (17 LBW, 11 VLBW) pre-mature newborns, n?=?228 simultaneous TTE (trans-aortic Doppler), and EV measurements (134 LBW, 94 VLBW) of stroke volume (SV) and heart rate (HR) were performed, thereof calculating body weight indexed SV (=SV*) and CO (=CO*) for all patients and the subgroups. Method comparison was performed by Bland–Altman plot, method precision expressed by calculation of the coefficient of variation (CV). Results: Mean CO* in all patients was 256.4?±?44.8 (TTE) and 265.3?±?48.8 (EV) ml/kg/min. Bias and precision were clinically acceptable, limits of agreement within the 30% criterion for method interchangeability (17). According to their different anatomic dimensions and pathophysiology, there were significant differences of SV(*), HR, and CO* for LBW and VLBW infants as well for inotropic treatment and ventilation mode. Conclusion: Extending recent publications on EV/TTE comparison in newborns, this study suggests that EV is also applicable in LWB/VLBW infants as a safe and easy to handle method for continuous CO monitoring in the NICU and PCICU. PMID:24724074

Grollmuss, Oswin; Gonzalez, Patricia

2014-01-01

107

Arterial pressure, cardiac output and systemic resistance before and after pithing in normotensive and spontaneously hypertensive rats.  

PubMed

After complete cardiovascular denervation mean arterial pressure (MAP) falls to almost equally low levels in spontaneously hypertensive rats (SHR) and normotensive control rats (NCR). This has earlier been suggested to indicate a dominance of neurogenic mechanisms in established SHR hypertension. -- In the present study, total peripheral resistance (TPR) remains, however, some 35 per cent higher in adult SHR than in NCR after pithing while cardiac output (CO), and stroke volume, is 35 per cent lower in SHR. These opposite differences in TPR and CO after denervation, resulting in equal MAP levels in SHR and NCR, seem rather to be a consequence of the rapidly established structural adaptation that affects all SHR high-pressure cardiovascular sections. Thus, the SHR precapillary resistance vessels display thickened walls and luminal narrowing, which keeps TPR higher than in NCR even during maximal vasodilatation. Due to hypertrophy, the SHR left ventricle exhibits a reduced myocardial stretch for a given filling pressure and stroke volume is consequently reduced more than in NCR after complete denervation. -- Paradoxically, therefore, rather than reflecting any dominance of neurogenic mechanisms in established SHR hypertension the MAP equalization in SHR and NCR after cardiovascular denervation emphasizes the hemodynamic importance of cardiovascular structural changes present in hypertension. PMID:1101646

Albrecht, I; Hallbäck, M; Julius, S; Lundgren, Y; Stage, L; Weiss, L; Folkow, B

1975-07-01

108

Cardiac output measured by acetylene rebreathing technique at rest and during exercise. Comparison of results obtained by various calculation procedures.  

PubMed

Cardiac output (Qc) was measured by a rebreathing technique, using acetylene and a mass-spectrometer for analyzing. In addition the rate of pulmonary uptake of O2 (VO2) during the rebreathing period and during a preceding steady-state period were determined. Measurements were made on 8 adult humans at rest and at different levels of exercise up to maximum at two occasions. The ratio (VO2 during steady-state/VO2 during rebreathing) was found to be significantly below 1 when the steady-state VO2 was below about 21 . min-1 and to be about 0.55 for subjects at rest. This indicates that VO2, and hence Qc, is increased by the rebreathing procedure when this involves deeper and more frequent respirations than those of the preceding period. Accordingly, when VO2 was below about 21 . min-1, the Qc value, calculated exclusively from acetylene concentrations recorded during rebreathing, was multiplied by the above-mentioned VO2-ratio. It is shown that this correcting procedure gives more reasonable values than those obtained by acetylene data alone. It is pointed out in what respects this correcting procedure of calculation deviates from that originally used by Grollman, and it is shown that there are only moderate differences between the results obtained by the two procedures. PMID:7195567

Kanstrup, I L; Hallbäck, I

1981-05-01

109

Effect of inspiration of 12% O? (balance N?) on cardiac output, respiration, oxygen saturation, and oxygen delivery.  

PubMed

Low arterial oxygen saturation (SaO(2)) will result in a reduced rate of arterial oxygen delivery to the tissues (DO(2)), unless there is a compensatory increase in cardiac output (CO) or haemoglobin concentration (Hb). An adequate DO(2) can therefore be maintained by increasing ventilation, CO, or both. Sustaining a tissue specific oxygen extraction is thought to play an important part in overall compensation. The present study has examined responses to acute hypoxic exposure in 8 volunteers (breathing 12% oxygen, balance nitrogen) and describes changes in CO, ventilation and the SaO(2). Aims included: examination of the extent of intersubject variations and seeing whether DO(2) was maintained. SaO(2), PCO(2), respiration (via stethograph) and Finapress (non-invasive) arterial blood pressure (BP) were recorded, firstly on air and then on 12% oxygen. CO was derived, off-line, from the BP record. CO was increased in 5 subjects (22%-45%) but was virtually unchanged in 3, and yet comparison for all 8 subjects showed that DO(2) on 12% oxygen was not significantly different from DO(2) on air (mean on air 1017 ml. min(-1); hypoxia 1080 ml. min(-1), p = 0.27). SaO(2) on 12% oxygen ranged between 85% and 93%. In conclusion, exposure to the same hypoxic gas mixture resulted in differing individual ventilatory and CO responses. However, DO(2) was well maintained. PMID:21445805

Bell, M; Thake, C D; Wolff, C B

2011-01-01

110

Quantification of Cardiac Sac Network Effects on a Movement-Related Parameter of Pyloric Network Output in the Lobster  

E-print Network

Quantification of Cardiac Sac Network Effects on a Movement- Related Parameter of Pyloric Network 29 September 2002 Thuma, Jeff B. and Scott L. Hooper. Quantification of cardiac sac network effects.1152/jn.00631.2002. Cardiac sac network activity (cycle period tens of seconds to minutes) has long been

Hooper, Scott

111

Arterial pressure-based cardiac output monitoring: a multicenter validation of the third-generation software in septic patients  

PubMed Central

Purpose Second-generation FloTrac software has been shown to reliably measure cardiac output (CO) in cardiac surgical patients. However, concerns have been raised regarding its accuracy in vasoplegic states. The aim of the present multicenter study was to investigate the accuracy of the third-generation software in patients with sepsis, particularly when total systemic vascular resistance (TSVR) is low. Methods Fifty-eight septic patients were included in this prospective observational study in four university-affiliated ICUs. Reference CO was measured by bolus pulmonary thermodilution (iCO) using 3–5 cold saline boluses. Simultaneously, CO was computed from the arterial pressure curve recorded on a computer using the second-generation (COG2) and third-generation (COG3) FloTrac software. CO was also measured by semi-continuous pulmonary thermodilution (CCO). Results A total of 401 simultaneous measurements of iCO, COG2, COG3, and CCO were recorded. The mean (95%CI) biases between COG2 and iCO, COG3 and iCO, and CCO and iCO were ?10 (?15 to ?5)% [?0.8 (?1.1 to ?0.4) L/min], 0 (?4 to 4)% [0 (?0.3 to 0.3) L/min], and 9 (6–13)% [0.7 (0.5–1.0) L/min], respectively. The percentage errors were 29 (20–37)% for COG2, 30 (24–37)% for COG3, and 28 (22–34)% for CCO. The difference between iCO and COG2 was significantly correlated with TSVR (r2 = 0.37, p < 0.0001). A very weak (r2 = 0.05) relationship was also observed for the difference between iCO and COG3. Conclusions In patients with sepsis, the third-generation FloTrac software is more accurate, as precise, and less influenced by TSVR than the second-generation software. Electronic supplementary material The online version of this article (doi:10.1007/s00134-010-2098-8) contains supplementary material, which is available to authorized users. PMID:21153399

Marx, Gernot; Tan, Andrew; Junker, Christopher; Van Nuffelen, Marc; Huter, Lars; Ching, Willy; Michard, Frederic; Vincent, Jean-Louis

2010-01-01

112

Modifications to the accuracy assessment analysis routine MLTCRP to produce an output file  

NASA Technical Reports Server (NTRS)

Modifications are described that were made to the analysis program MLTCRP in the accuracy assessment software system to produce a disk output file. The output files produced by this modified program are used to aggregate data for regions greater than a single segment.

Carnes, J. G.

1978-01-01

113

Role of frailty assessment in patients undergoing cardiac interventions  

PubMed Central

Average life expectancy is increasing in the western world resulting in a growing number of frail individuals with coronary heart disease, often associated with comorbidities. Decisions to proceed to invasive interventions in elderly frail patients is challenging because they may gain benefit, but are also at risk of procedure-related complications. Current risk scores designed to predict mortality in cardiac procedures are mainly based on clinical and angiographic factors, with limitations in the elderly because they are mainly derived from a middle-aged population, do not account for frailty and do not predict the impact of the procedure on quality of life which often matters more to elderly patients than mortality. Frailty assessment has emerged as a measure of biological age that correlates well with quality of life, hospital admissions and mortality. Potentially, the incorporation of frailty into current risk assessment models will cause a shift towards more appropriate care. The need for a more accurate method of risk stratification incorporating frailty, particularly for elderly patients is pressing. This article reviews the association between frailty and cardiovascular disease, the impact of frailty on outcomes of cardiac interventions and suggests ways in which frailty assessment could be incorporated into cardiology clinical practice.

Rowe, Rebecca; Iqbal, Javaid; Murali-krishnan, Rachel; Sultan, Ayyaz; Orme, Rachel; Briffa, Norman; Denvir, Martin; Gunn, Julian

2014-01-01

114

PKPD modelling of the interrelationship between mean arterial BP, cardiac output and total peripheral resistance in conscious rats  

PubMed Central

Background and Purpose The homeostatic control of arterial BP is well understood with changes in BP resulting from changes in cardiac output (CO) and/or total peripheral resistance (TPR). A mechanism-based and quantitative analysis of drug effects on this interrelationship could provide a basis for the prediction of drug effects on BP. Hence, we aimed to develop a mechanism-based pharmacokinetic-pharmacodynamic (PKPD) model in rats that could be used to characterize the effects of cardiovascular drugs with different mechanisms of action (MoA) on the interrelationship between BP, CO and TPR. Experimental Approach The cardiovascular effects of six drugs with diverse MoA, (amlodipine, fasudil, enalapril, propranolol, hydrochlorothiazide and prazosin) were characterized in spontaneously hypertensive rats. The rats were chronically instrumented with ascending aortic flow probes and/or aortic catheters/radiotransmitters for continuous recording of CO and/or BP. Data were analysed in conjunction with independent information on the time course of drug concentration using a mechanism-based PKPD modelling approach. Key Results By simultaneous analysis of the effects of six different compounds, the dynamics of the interrelationship between BP, CO and TPR were quantified. System-specific parameters could be distinguished from drug-specific parameters indicating that the model developed is drug-independent. Conclusions and Implications A system-specific model characterizing the interrelationship between BP, CO and TPR was obtained, which can be used to quantify and predict the cardiovascular effects of a drug and to elucidate the MoA for novel compounds. Ultimately, the proposed PKPD model could be used to predict the effects of a particular drug on BP in humans based on preclinical data. PMID:23849040

Snelder, N; Ploeger, B A; Luttringer, O; Rigel, D F; Webb, R L; Feldman, D; Fu, F; Beil, M; Jin, L; Stanski, D R; Danhof, M

2013-01-01

115

Tidal volume, cardiac output and functional residual capacity determine end-tidal CO2 transient during standing up in humans  

PubMed Central

In man assuming the upright position, end-tidal PCO2 (PETCO2) decreases. With the rising interest in cerebral autoregulation during posture change, which is known to be affected by PETCO2, we sought to determine the factors leading to hypocapnia during standing up from the supine position. To study the contribution of an increase in tidal volume (VT) and breathing frequency, a decrease in stroke volume (SV), a ventilation–perfusion (V/Q) gradient and an increase in functional residual capacity (FRC) to hypocapnia in the standing position, we developed a mathematical model of the lung to follow breath-to-breath variations in PETCO2. A gravity-induced apical-to-basal V/Q gradient in the lung was modelled using nine lung segments. We tested the model using an eight-subject data set with measurements of VT, pulmonary O2 uptake and breath-to-breath lumped SV. On average, the PETCO2 decreased from 40 mmHg to 36 mmHg after 150 s standing. Results show that the model is able to track breath-to-breath PETCO2 variations (r2= 0.74, P < 0.05). Model parameter sensitivity analysis demonstrates that the decrease in PETCO2 during standing is due primarily to increased VT, and transiently to decreased SV and increased FRC; a slight gravity-induced V/Q mismatch also contributes to the hypocapnia. The influence of cardiac output on hypocapnia in the standing position was verified in experiments on human subjects, where first breathing alone, and then breathing, FRC and V/Q were controlled. PMID:14608002

Gisolf, Janneke; Wilders, Ronald; Immink, Rogier V; van Lieshout, Johannes J; Karemaker, John M

2004-01-01

116

Cardiac output and cardiac index measured with cardiovascular magnetic resonance in healthy subjects, elite athletes and patients with congestive heart failure  

PubMed Central

Background Cardiovascular Magnetic Resonance (CMR) enables non-invasive quantification of cardiac output (CO) and thereby cardiac index (CI, CO indexed to body surface area). The aim of this study was to establish if CI decreases with age and compare the values to CI for athletes and for patients with congestive heart failure (CHF). Methods CI was measured in 144 healthy volunteers (39?±?16?years, range 21–81?years, 68 females), in 60 athletes (29?±?6?years, 30 females) and in 157 CHF patients with ejection fraction (EF) below 40% (60?±?13?years, 33 females). CI was calculated using aortic flow by velocity-encoded CMR and is presented as mean?±?SD. Flow was validated in vitro using a flow phantom and in 25 subjects with aorta and pulmonary flow measurements. Results There was a slight decrease of CI with age in healthy subjects (8?ml/min/m2 per year, r2?=?0.07, p?=?0.001). CI in males (3.2?±?0.5?l/min/m2) and females (3.1?±?0.4?l/min/m2) did not differ (p?=?0.64). The mean?±?SD of CI in healthy subjects in the age range of 20–29 was 3.3?±?0.4?l/min/m2, in 30–39?years 3.3?±?0.5?l/min/m2, in 40–49?years 3.1?±?0.5?l/min/m2, 50–59?years 3.0?±?0.4?l/min/m2 and >60?years 3.0?±?0.4?l/min/m2. There was no difference in CI between athletes and age-controlled healthy subjects but HR was lower and indexed SV higher in athletes. CI in CHF patients (2.3?±?0.6?l/min/m2) was lower compared to the healthy population (p?

2012-01-01

117

Automatic Assessment of Socioeconomic Impact on Cardiac Rehabilitation  

PubMed Central

Disability-Adjusted Life Years (DALYs) and Quality-Adjusted Life Years (QALYs), which capture life expectancy and quality of the remaining life-years, are applied in a new method to measure socioeconomic impacts related to health. A 7-step methodology estimating the impact of health interventions based on DALYs, QALYs and functioning changes is presented. It relates the latter (1) to the EQ-5D-5L questionnaire (2) to automatically calculate the health status before and after the intervention (3). This change of status is represented as a change in quality of life when calculating QALYs gained due to the intervention (4). In order to make an economic assessment, QALYs gained are converted to DALYs averted (5). Then, by inferring the cost/DALY from the cost associated to the disability in terms of DALYs lost (6) and taking into account the cost of the action, cost savings due to the intervention are calculated (7) as an objective measure of socioeconomic impact. The methodology is implemented in Java. Cases within the framework of cardiac rehabilitation processes are analyzed and the calculations are based on 200 patients who underwent different cardiac-rehabilitation processes. Results show that these interventions result, on average, in a gain in QALYs of 0.6 and a cost savings of 8,000 €. PMID:24284349

Calvo, Mireia; Subirats, Laia; Ceccaroni, Luigi; Maroto, Jose Maria; de Pablo, Carmen; Miralles, Felip

2013-01-01

118

Effects of head-up tilt on mean arterial pressure, heart rate, and regional cardiac output distribution in aging rats  

E-print Network

Many senescent individuals demonstrate an inability to regulate mean arterial pressure (MAP) in response to standing or head-up tilt; however, whether this aging effect is the result of depressed cardiac function or an inability to reduce peripheral...

Ramsey, Michael Wiechmann

2006-04-12

119

Determinants of mobile phone output power in a multinational study: implications for exposure assessment  

Microsoft Academic Search

Objectives:The output power of a mobile phone is directly related to its radiofrequency (RF) electromagnetic field strength, and may theoretically vary substantially in different networks and phone use circumstances due to power control technologies. To improve indices of RF exposure for epidemiological studies, we assessed determinants of mobile phone output power in a multinational study.Methods:More than 500 volunteers in 12

M Vrijheid; S Mann; P Vecchia; J Wiart; M Taki; L Ardoino; B K Armstrong; A Auvinen; D Bédard; G Berg-Beckhoff; J Brown; A Chetrit; H Collatz-Christensen; E Combalot; A Cook; I Deltour; M Feychting; G G Giles; S J Hepworth; I Iavarone; C Johansen; D Krewski; P Kurttio; S Lagorio; S Lönn; M McBride; L Montestrucq; R C Parslow; S Sadetzki; J Schüz; T Tynes; A Woodward; E Cardis

2009-01-01

120

In vertebrates, short-term imbalances in blood pressure are regulated by reflex changes in cardiac output and peripheral  

E-print Network

In vertebrates, short-term imbalances in blood pressure are regulated by reflex changes in cardiac identified in many vertebrate species (see review by Bagshaw, 1985). In reptiles, the anatomy, and probably birds, the existence of myelinated baroreceptors (with thresholds well below normal arterial

Altimiras, Jordi

121

Modifications to the accuracy assessment analysis routine SPATL to produce an output file  

NASA Technical Reports Server (NTRS)

The SPATL is an analysis program in the Accuracy Assessment Software System which makes comparisons between ground truth information and dot labeling for an individual segment. In order to facilitate the aggregation cf this information, SPATL was modified to produce a disk output file containing the necessary information about each segment.

Carnes, J. G.

1978-01-01

122

Economic Input-Output Life Cycle Assessment of Water Reuse Strategies in Residential Buildings  

EPA Science Inventory

This paper evaluates the environmental sustainability and economic feasibility of four water reuse designs through economic input-output life cycle assessments (EIO-LCA) and benefit/cost analyses. The water reuse designs include: 1. Simple Greywater Reuse System for Landscape Ir...

123

The output of budesonide from spacer devices assessed under simulated breathing conditions  

Microsoft Academic Search

Background: Spacer devices are increasingly used to aid inhalational therapy, and many different devices are available. Patient and spacer size and spacer static charge may affect drug delivery, but the optimum spacer size and method of reducing static charge is not certain. Objective: We sought to determine the output of budesonide from 3 different spacer devices when assessed by using

Peter W. Barry; Chris O’Callaghan

1999-01-01

124

CO(2)-Dependent vasomotor reactivity of cerebral arteries in patients with severe traumatic brain injury: time course and effect of augmentation of cardiac output with dobutamine.  

PubMed

Failing cerebral blood flow (CBF) autoregulation may contribute to cerebral damage after traumatic brain injury (TBI). The purpose of this study was to describe the time course of CO(2)-dependent vasoreactivity, measured as CBF velocity in response to hyperventilation (vasomotor reactivity [VMR] index). We included 13 patients who had had severe TBI, 8 of whom received norepinephrine (NE) based on clinical indication. In these patients, measurements were also performed after dobutamine administration, with a goal of increasing cardiac output by 30%. Blood flow velocity was measured with transcranial Doppler ultrasound in both hemispheres. All patients except one had an abnormal VMR index in at least one hemisphere within the first 24?h after TBI. In those patients who did not receive catecholamines, mean VMR index recovered within the first 48 to 72?h. In contrast, in patients who received NE within the first 48?h period, VMR index did not recover on the second day. Cardiac output and mean CBF velocity increased significantly during dobutamine administration, but VMR index did not change significantly. In conclusion, CO(2) vasomotor reactivity was abnormal in the first 24?h after TBI in most of the patients, but recovered within 48?h in those patients who did not receive NE, in contrast to those eventually receiving the drug. Addition of dobutamine to NE had variable but overall insignificant effects on CO(2) vasomotor reactivity. PMID:21501044

Haenggi, Matthias; Andermatt, Anna; Anthamatten, Claudia; Galimanis, Aikaterini; Mono, Marie-Luise; Alfieri, Alexander; Fung, Christian; Takala, Jukka; Jakob, Stephan M

2012-06-10

125

Output power levels from mobile phones in different geographical areas; implications for exposure assessment  

PubMed Central

Background: The power level used by the mobile phone is one of the most important factors determining the intensity of the radiofrequency exposure during a call. Mobile phone calls made in areas where base stations are densely situated (normally urban areas) should theoretically on average use lower output power levels than mobile phone calls made in areas with larger distances between base stations (rural areas). Aims: To analyse the distribution of power levels from mobile phones in four geographical areas with different population densities. Methods: The output power for all mobile phone calls managed by the GSM operator Telia Mobile was recorded during one week in four defined areas (rural, small urban, suburban, and city area) in Sweden. The recording included output power for the 900 MHz and the 1800 MHz frequency band. Results: In the rural area, the highest power level was used about 50% of the time, while the lowest power was used only 3% of the time. The corresponding numbers for the city area were approximately 25% and 22%. The output power distribution in all defined urban areas was similar. Conclusion: In rural areas where base stations are sparse, the output power level used by mobile phones are on average considerably higher than in more densely populated areas. A quantitative assessment of individual exposure to radiofrequency fields is important for epidemiological studies of possible health effects for many reasons. Degree of urbanisation may be an important parameter to consider in the assessment of radiofrequency exposure from mobile phone use. PMID:15317918

Lonn, S; Forssen, U; Vecchia, P; Ahlbom, A; Feychting, M

2004-01-01

126

Imminent Cardiac Risk Assessment via Optical Intravascular Biochemical Analysis  

SciTech Connect

Heart disease is by far the biggest killer in the United States, and type II diabetes, which affects 8% of the U.S. population, is on the rise. In many cases, the acute coronary syndrome and/or sudden cardiac death occurs without warning. Atherosclerosis has known behavioral, genetic and dietary risk factors. However, our laboratory studies with animal models and human post-mortem tissue using FT-IR microspectroscopy reveal the chemical microstructure within arteries and in the arterial walls themselves. These include spectra obtained from the aortas of ApoE-/- knockout mice on sucrose and normal diets showing lipid deposition in the former case. Also pre-aneurysm chemical images of knockout mouse aorta walls, and spectra of plaque excised from a living human patient are shown for comparison. In keeping with the theme of the SPEC 2008 conference Spectroscopic Diagnosis of Disease this paper describes the background and potential value of a new catheter-based system to provide in vivo biochemical analysis of plaque in human coronary arteries. We report the following: (1) results of FT-IR microspectroscopy on animal models of vascular disease to illustrate the localized chemical distinctions between pathological and normal tissue, (2) current diagnostic techniques used for risk assessment of patients with potential unstable coronary syndromes, and (3) the advantages and limitations of each of these techniques illustrated with patent care histories, related in the first person, by the physician coauthors. Note that the physician comments clarify the contribution of each diagnostic technique to imminent cardiac risk assessment in a clinical setting, leading to the appreciation of what localized intravascular chemical analysis can contribute as an add-on diagnostic tool. The quality of medical imaging has improved dramatically since the turn of the century. Among clinical non-invasive diagnostic tools, laboratory tests of body fluids, EKG, and physical examination are still the first line of defense. However, with the fidelity of 64-slice CT imaging, this technique has recently become an option when the patient presents with symptoms of reduced arterial flow. Single photon emission computerized tomography (SPECT) treadmill exercise testing is a standard non-invasive test for decreased perfusion of heart muscle, but is time consuming and not suited for emergent evaluation. Once the invasive clinical option of catherization is chosen, this provides the opportunity for intravascular ultrasound (IVUS) imaging. As the probe is pulled through the artery, the diameter at different parts is measurable, and monochrome contrast in the constricted area reveals the presence of tissue with a different ultrasonic response. Also, via an optical catheter with a fiber-optic conductor, the possibly of spectroscopic analysis of arterial walls is now a reality. In this case, the optical transducer is coupled to a near-infrared spectrometer. Revealing the arterial chemical health means that plaque vulnerability and imminent risk could be assessed by the physician. The classical emergency use of catherization involves a contrast agent and dynamic X-ray imaging to locate the constriction, determine its severity, and possibly perform angioplasty, and stent placement.

Wetzel, D.; Wetzel, L; Wetzel, M; Lodder, R

2009-01-01

127

Solving ODEs: Cardiac drug risk assessment The heat equation and finite elements: electrical propagation in the heart Object-oriented scientific computing: Applications  

E-print Network

Solving ODEs: Cardiac drug risk assessment The heat equation and finite elements: electrical;Solving ODEs: Cardiac drug risk assessment The heat equation and finite elements: electrical propagation in the heart Solving ODEs: Cardiac drug risk assessment #12;Solving ODEs: Cardiac drug risk assessment The heat

Martin, Ralph R.

128

Non-invasive in vivo measurement of cardiac output in C57BL/6 mice using high frequency transthoracic ultrasound: evaluation of gender and body weight effects.  

PubMed

Even though mice are being increasingly used as models for human cardiovascular diseases, non-invasive monitoring of cardiovascular parameters such as cardiac output (CO) in this species is challenging. In most cases, the effects of gender and body weight (BW) on these parameters have not been studied. The objective of this study was to provide normal reference values for CO in C57BL/6 mice, and to describe possible gender and/or BW associated differences between them. We used 30-MHz transthoracic Doppler ultrasound to measure hemodynamic parameters in the ascending aorta [heart rate (HR), stroke volume (SV), stroke index (SI), CO, and cardiac index (CI)] in ten anesthetized mice of either sex. No differences were found for HR, SV, and CO. Both SI and CI were statistically lower in males. However, after normalization for BW, these differences disappeared. These results suggest that if comparisons of cardiovascular parameters are to be made between male and female mice, values should be standardized for BW. PMID:24852337

Domínguez, Elisabet; Ruberte, Jesús; Ríos, José; Novellas, Rosa; Del Alamo, Maria Montserrat Rivera; Navarro, Marc; Espada, Yvonne

2014-10-01

129

Task based assessment of cardiac function in Monte Carlo simulated gated Tl201 perfusion SPECT: A human observer study  

Microsoft Academic Search

Different implementations of the receiver operator characteristic (ROC) method in cardiac perfusion SPECT have been described. However, none has attempted to independently assess cardiac function. The aim of this study was, therefore, to design and execute a human observer ROC study that includes the evaluation of cardiac function and perfusion. Due to the lack of a gold standard, our initial

P. Hendrik Pretorius; J. Michael O'Connor; Robert Licho; Jovan G. Brankov

2010-01-01

130

Prospective assessment of intraoperative precursor events during cardiac surgery  

Microsoft Academic Search

Objective: Increasing attention has been afforded to the ubiquity of medical error and associated adverse events in medicine. There remains little data on the frequency and nature of precursor events in cardiac surgery, and we sought to characterize this. Methods: Detailed, anonymous information regarding intraoperative precursor events (which may result in adverse events) was collected prospectively from six key members

Daniel R. Wong; Thomas J. Vander Salm; Imtiaz S. Ali; Arvind K. Agnihotri; Richard M. J. Bohmer; David F. Torchiana

2006-01-01

131

In emergently ventilated trauma patients, low end-tidal CO2 and low cardiac output are associated and correlate with hemodynamic instability, hemorrhage, abnormal pupils, and death  

PubMed Central

Background In a smaller experience, the authors previously demonstrated that end-tidal carbon dioxide (PetCO2) and cardiac output (CO) had a positive association in emergently intubated trauma patients during Emergency Department resuscitation. The aim of this larger study was to reassess the relationship of PetCO2 with CO and identify patient risk-conditions influencing PetCO2 and CO values. Methods The investigation consists of acutely injured trauma patients requiring emergency tracheal intubation. The study focuses on the prospective collection of PetCO2 and noninvasive CO monitor (NICOM®) values in the Emergency Department. Results From the end of March through August 2011, 73 patients had 318 pairs of PetCO2 (mm Hg) and CO (L/min.) values. Mean data included Injury Severity Score (ISS) ?15 in 65.2%, Glasgow Coma Score of 6.4?±?4.6, hypotension in 19.0%, and death in 34.3%. With PetCO2???25 (15.9?±?8.0), systolic blood pressure was 77.0?±?69, CO was 3.2?±?3.0, cardiac arrest was 60.4%, and mortality was 84.9%. During hypotension, CO was lower with major blood loss (1.9), than without major loss (5.0; P?=?0.0008). Low PetCO2 was associated with low CO (P??20, hypotension, bradycardia, major blood loss, abnormal pupils, cardiac arrest, and death. Low CO was associated (P???0.0059) with ISS?>?20, hypotension, bradycardia, major blood loss, abnormal pupils, cardiac arrest, and death. Conclusions During emergency department resuscitation, a decline in PetCO2 correlates with decreases in noninvasive CO in emergently intubated trauma patients. Decreasing PetCO2 and declining NICOM CO are associated with hemodynamic instability, hemorrhage, abnormal pupils, and death. The study indicates that NICOM CO values are clinically discriminate and have physiologic validity. PMID:24020798

2013-01-01

132

Comprehensive assessment of frailty for elderly high-risk patients undergoing cardiac surgery  

Microsoft Academic Search

Objective: Cardiosurgical operative risk can be assessed using the logistic European system for cardiac operative risk evaluation (EuroSCORE) and the Society of Thoracic Surgeons (STS) score. Factors other than medical diagnoses and laboratory values such as the ‘biological age’ are not included in these scores. The aim of the study was to evaluate an additional assessment of frailty in routine

Simon Sündermann; Anika Dademasch; Julian Praetorius; Jörg Kempfert; Todd Dewey; Volkmar Falk; Friedrich-Wilhelm Mohr; Thomas Walther

2011-01-01

133

Cardiac and coronary CT comprehensive imaging approach in the assessment of coronary heart disease  

Microsoft Academic Search

Cardiac CT is a rapidly advancing technology. Non-invasive CT coronary angiography is an established technique for assessing coronary heart disease with accuracy similar to invasive coronary angiography. CT myocardial perfusion imaging can now identify perfusion defects in animal models and humans. MRI is the current ‘gold standard’ for the assessment of myocardial viability, but it is now also possible to

M C Williams; J H Reid; G McKillop; N W Weir; E J R van Beek; N G Uren; D E Newby

2011-01-01

134

The feasibility and applications of non-invasive cardiac output monitoring, thromboelastography and transit-time flow measurement in living-related renal transplantation surgery: results of a prospective pilot observational study  

PubMed Central

Introduction Delayed graft function (DGF) remains a significant and detrimental postoperative phenomenon following living-related renal allograft transplantation, with a published incidence of up to 15%. Early therapeutic vasodilatory interventions have been shown to improve DGF, and modifications to immunosuppressive regimens may subsequently lessen its impact. This pilot study assesses the potential applicability of perioperative non-invasive cardiac output monitoring (NICOM), transit-time flow monitoring (TTFM) of the transplant renal artery and pre-/perioperative thromboelastography (TEG) in the early prediction of DGF and perioperative complications. Methods Ten consecutive living-related renal allograft recipients were studied. Non-invasive cardiac output monitoring commenced immediately following induction of anaesthesia and was maintained throughout the perioperative period. Doppler-based TTFM was performed during natural haemostatic pauses in the transplant surgery: immediately following graft reperfusion and following ureteric implantation. Central venous blood sampling for TEG was performed following induction of anaesthesia and during abdominal closure. Results A single incidence of DGF was seen within the studied cohort and one intra-operative (thrombotic) complication noted. NICOM confirmed a predictable trend of increased cardiac index (CI) following allograft reperfusion (mean CI - clamped: 3.17?±?0.29 L/min/m2, post-reperfusion: 3.50?±?0.35 L/min/m2; P?

2014-01-01

135

Multidetector-Row CT for Assessment of Cardiac Valves  

Microsoft Academic Search

Imaging of the heart with computed tomography (CT) is challenging because the heart is continuously moving during data acquisition.\\u000a As a result of the limited temporal resolution, the use of single-detector helical CT for noninvasive cardiac imaging was\\u000a limited and resulted often in images with a high content of artifacts. The introduction of multidetector-row CT (MDCT) scanners\\u000a by the end

Jürgen K. Willmann; Dominik Weishaupt

136

Assessment of Cardiac Functions in Infants with Cow's Milk Allergy  

PubMed Central

Background Cow’s milk allergy is the most common food allergy in children, with rates estimated at 1.9% to 4.9%. Clinical phenotypes of cow’s milk allergy are varied and involve 1 or more target organs, with the main targets being the skin, respiratory system, and gastrointestinal tract. To date, no studies have investigated detailed cardiac function in children with cow’s milk allergy. The current study aimed to investigate cardiac function in infants with cow’s milk allergy. Material/Methods We studied 42 infants with cow’s milk allergy and 30 age- and sex-matched healthy subjects. Cardiac functions were evaluated by M-mode, pulsed-wave, and tissue Doppler echocardiography. Results There were no significant differences in ejection fraction or mitral and tricuspid annular plane systolic excursion between the 2 groups. Pulsed-wave Doppler-derived E/A ratios in mitral and tricuspid valves were similar in both groups. Ea/Aa ratios in the left ventricle posterior wall and right ventricle free wall were lower in patients with cow’s milk allergy than in the control group. The E/Ea ratio in the left ventricle, isovolumic relaxation time, deceleration time, and right and left ventricular myocardial performance indices were higher in patients in the study group. Conclusions Our study identified reduced early diastolic tissue Doppler velocities in infants with cow’s milk allergy. PMID:25098395

Ece, Ibrahim; Demiroren, Kaan; Demir, Nihat; Uner, Abdurrahman; Balli, Sevket

2014-01-01

137

A model-free method for mass spectrometer response correction. [for oxygen consumption and cardiac output calculation  

NASA Technical Reports Server (NTRS)

A new method for correction of mass spectrometer output signals is described. Response-time distortion is reduced independently of any model of mass spectrometer behavior. The delay of the system is found first from the cross-correlation function of a step change and its response. A two-sided time-domain digital correction filter (deconvolution filter) is generated next from the same step response data using a regression procedure. Other data are corrected using the filter and delay. The mean squared error between a step response and a step is reduced considerably more after the use of a deconvolution filter than after the application of a second-order model correction. O2 consumption and CO2 production values calculated from data corrupted by a simulated dynamic process return to near the uncorrupted values after correction. Although a clean step response or the ensemble average of several responses contaminated with noise is needed for the generation of the filter, random noise of magnitude not above 0.5 percent added to the response to be corrected does not impair the correction severely.

Shykoff, Barbara E.; Swanson, Harvey T.

1987-01-01

138

A Risk-Based Approach to Health Impact Assessment for Input-Output Analysis, Part 1: Methodology (7 pp)  

Microsoft Academic Search

Goal, Scope and Background. Incorporation of exposure and risk concepts into life cycle impact assessment (LCIA) is often impaired by the number of sources and the complexity of site-specific impact assessment, especially when input-output (I-O) analysis is used to evaluate upstream processes. This makes it difficult to interpret LCIA outputs, especially in policy contexts. In this study, we develop an

Yurika Nishioka; Jonathan I. Levy; Gregory A. Norris; Deborah H. Bennett; John D. Spengler

2005-01-01

139

Effects of active chronic cocaine use on cardiac sympathetic neuronal function assessed by carbon-11hydroxyephedrine  

Microsoft Academic Search

Cardiac toxicity of cocaine has been linked to its inhibitory effect on norepinephrine reuptake by sympathetic nerve terminals of the heart. Carbon-11-hydroxyephedrine is a positron-emitting tracer that has been validated as a highly specific marker for norepinephrine transporter activity of the sympathetic nerve terminals and thus makes possible in vivo assessment of the effect of cocaine on norepinephrine reuptake and

P. G. Melon; C. J. Boyd; S. McVey

1997-01-01

140

Heart mass and the maximum cardiac output of birds and mammals: implications for estimating the maximum aerobic power input of flying animals  

PubMed Central

Empirical studies of cardiovascular variables suggest that relative heart muscle mass (relative Mh) is a good indicator of the degree of adaptive specialization for prolonged locomotor activities, for both birds and mammals. Reasonable predictions for the maximum oxygen consumption of birds during flight can be obtained by assuming that avian heart muscle has the same maximum physiological and biomechanical performance as that of terrestrial mammals. Thus, data on Mh can be used to provide quantitative estimates for the maximum aerobic power input (aerobic Pi,max) available to animals during intense levels of locomotor activity. The maximum cardiac output of birds and mammals is calculated to scale with respect to Mh (g) as 213 Mh0.88+-0.04 (ml min-1), while aerobic Pi,max is estimated to scale approximately as 11 Mh0.88+-0.09 (W). In general, estimated inter-species aerobic Pi,max, based on Mh for all bird species (excluding hummingbirds), is calculated to scale with respect to body mass (Mb in kg) as 81 Mb0.82+-0.11 (W). Comparison of family means for Mh indicate that there is considerable diversity in aerobic capacity among birds and mammals, for example, among the medium to large species of birds the Tinamidae have the smallest relative Mh (0.25 per cent) while the Otidae have unusually large relative Mh (1.6 per cent). Hummingbirds have extremely large relative Mh (2.28 per cent), but exhibit significant sexual dimorphism in their scaling of Mh and flight muscle mass, so that when considering hummingbird flight performance it may be useful to control for sexual differences in morphology. The estimated scaling of aerobic Pi,max (based on Mh and Mb in g) for male and female hummingbirds is 0.51 Mb0.83 +/-0.07 and 0.44 Mb0.85+- 0.11 (W), respectively. Locomotory muscles are dynamic structures and it might be anticipated that where additional energetic 'costs' occur seasonally (e.g. due to migratory fattening or the development of large secondary sexual characteristics) then the relevant cardiac and locomotor musculature might also be regulated seasonally. This is an important consideration, both due to the intrinsic interest of studying muscular adaptation to changes in energy demand, but also as a confounding variable in the practical use of heart rate to estimate the energetics of animals. Haemoglobin concentration (or haematocrit) may also be a confounding variable. Thus, it is concluded that data on the cardiovascular and flight muscle morphology of animals provides essential information regarding the behavioural, ecological and physiological significance of the flight performance of animals.

Bishop, C. M.

1997-01-01

141

Assessment of cardiac functions in fetuses of gestational diabetic mothers.  

PubMed

We investigated cardiac function in 67 fetuses of gestational diabetic mothers (FGDMs) and 122 fetuses of healthy mothers between 24 and 36 weeks of gestation. Cardiac functions were evaluated by M-mode, pulsed-wave, and tissue Doppler echocardiography. Fetal echocardiograms were performed at 24, 28, 32, and 36 weeks of gestation. Glycated hemoglobin (HbA1c) levels were obtained from all pregnant women at 24 weeks of gestation. The mean age of diabetic pregnant women was significantly greater than that of controls. Serum HbA1c values of both groups were within normal limits, but they were significantly greater in the diabetic group (p = 0.003). The increase in peak aortic and pulmonary artery velocities were greater in FGDM (p < 0.001). No pathological interventricular septal (IVS) hypertrophy was observed. There was a significant increase in IVS thickness in FGDM compared with controls, which was more prominent at the end of the third trimester (p < 0.001). During the course of pregnancy, mitral E-wave (p < 0.001), A-wave (p = 0.007), tricuspid E-wave (p < 0.001) and A-wave (p = 0.002) velocities were greater in FGDM. The increases in mitral E/A and tricuspid E/A ratios were lower in FGDM with advancing gestation. The E a-wave (p = 0.02), A a-wave (p = 0.04), and S a-wave (p < 0.001) velocities of the right-ventricular (RV) free wall and the E a (p = 0.02) and A a (p = 0.01) velocities of the left-ventricle (LV) posterior wall were greater in FGDM during the course of pregnancy. The E a/A a ratio of the RV posterior wall was greater in FGDM with advancing gestation (p < 0.03). LV and RV E/E a ratios were similar in both groups. The LV myocardial performance index measured by pulsed-wave Doppler was greater in FGDM (p < 0.001). We detected diastolic dysfunction in FGDM. The data suggest that gestational diabetes mellitus may impair ventricular diastolic functions without causing pathological fetal myocardial hypertrophy. We detected subclinical diastolic dysfunction using both pulsed-wave and tissue Doppler imaging in FGDM. PMID:23780554

Balli, Sevket; Pac, Feyza Aysenur; Ece, ?brahim; Oflaz, Mehmet Burhan; Kibar, Ayse Esin; Kandemir, Ömer

2014-01-01

142

Increased cardiac output, not pulmonary artery systolic pressure, increases intrapulmonary shunt in healthy humans breathing room air and 40% O2.  

PubMed

Blood flow through intrapulmonary arteriovenous anastomoses (IPAVAs) has been demonstrated to increase in healthy humans during a variety of conditions; however, whether or not this blood flow represents a source of venous admixture (Q? VA /Q?T) that impairs pulmonary gas exchange efficiency (i.e. increases the alveolar-to-arterial PO2 difference (A-aDO2)) remains controversial and unknown. We hypothesized that blood flow through IPAVAs does provide a source of Q? VA /Q?T. To test this, blood flow through IPAVAs was increased in healthy humans at rest breathing room air and 40% O2: (1) during intravenous adrenaline (epinephrine) infusion at 320 ng kg(-1) min(-1) (320 ADR), and (2) with vagal blockade (2 mg atropine), before and during intravenous adrenaline infusion at 80 ng kg(-1) min(-1) (ATR + 80 ADR). When breathing room air the A-aDO2 increased by 6 ± 2 mmHg during 320 ADR and by 5 ± 2 mmHg during ATR + 80 ADR, and the change in calculated Q? VA /Q?T was +2% in both conditions. When breathing 40% O2, which minimizes contributions from diffusion limitation and alveolar ventilation-to-perfusion inequality, the A-aDO2 increased by 12 ± 7 mmHg during 320 ADR, and by 9 ± 6 mmHg during ATR + 80 ADR, and the change in calculated Q? VA /Q?T was +2% in both conditions. During 320 ADR cardiac output (Q?T) and pulmonary artery systolic pressure (PASP) were significantly increased; however, during ATR + 80 ADR only Q?T was significantly increased, yet blood flow through IPAVAs as detected with saline contrast echocardiography was not different between conditions. Accordingly, we suggest that blood flow through IPAVAs provides a source of intrapulmonary shunt, and is mediated primarily by increases in Q?T rather than PASP. PMID:25085889

Elliott, Jonathan E; Duke, Joseph W; Hawn, Jerold A; Halliwill, John R; Lovering, Andrew T

2014-10-15

143

Effects of active chronic cocaine use on cardiac sympathetic neuronal function assessed by carbon-11-hydroxyephedrine  

SciTech Connect

Cardiac toxicity of cocaine has been linked to its inhibitory effect on norepinephrine reuptake by sympathetic nerve terminals of the heart. Carbon-11-hydroxyephedrine is a positron-emitting tracer that has been validated as a highly specific marker for norepinephrine transporter activity of the sympathetic nerve terminals and thus makes possible in vivo assessment of the effect of cocaine on norepinephrine reuptake and storage in the cardiac sympathetic nerve terminals. The aim of the study was to use the catecholamine analog {sup 11}C-hydroxyephedrine with PET to determine whether active chronic use of cocaine in women modifies the function of sympathetic nerve terminals of the heart. Six normal female volunteers and nine female active chronic cocaine users were studied. Cardiac regional {sup 11}C-hydroxyephedrine uptake and blood flow, as assessed with {sup 13}N-ammonia, were determined using semi-quantitative polar map analysis of myocardial tracer distribution. Carbon-11-hydroxyephedrine cardiac retention was quantified using dynamic data acquisition and kinetic analysis of blood and tissue activity. 27 refs., 4 figs., 3 tabs.

Melon, P.G.; Boyd, C.J.; McVey, S. [Univ. of Michigan Medical Center, Ann Arbor, MI (United States)]|[Univ. of Michigan, Ann Arbor, MI (United States)] [and others

1997-03-01

144

Bayesian Spatial-temporal Model for Cardiac Congenital Anomalies and Ambient Air Pollution Risk Assessment  

PubMed Central

We introduce a Bayesian spatial-temporal hierarchical multivariate probit regression model that identifies weeks during the first trimester of pregnancy which are impactful in terms of cardiac congenital anomaly development. The model is able to consider multiple pollutants and a multivariate cardiac anomaly grouping outcome jointly while allowing the critical windows to vary in a continuous manner across time and space. We utilize a dataset of numerical chemical model output which contains information regarding multiple species of PM2.5. Our introduction of an innovative spatial-temporal semiparametric prior distribution for the pollution risk effects allows for greater flexibility to identify critical weeks during pregnancy which are missed when more standard models are applied. The multivariate kernel stick-breaking prior is extended to include space and time simultaneously in both the locations and the masses in order to accommodate complex data settings. Simulation study results suggest that our prior distribution has the flexibility to outperform competitor models in a number of data settings. When applied to the geo-coded Texas birth data, weeks 3, 7 and 8 of the pregnancy are identified as being impactful in terms of cardiac defect development for multiple pollutants across the spatial domain. PMID:23482298

Warren, Joshua; Fuentes, Montserrat; Herring, Amy; Langlois, Peter

2013-01-01

145

Automatic Assessment of Cardiac Perfusion Hildur Olafsdottir1  

E-print Network

Appearance Mod- els (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion MRI has proven to be a powerful method to assess coronary artery diseases. The ultimate goal of the analysis is to obtain a full quantifica- tion of the perfusion in ml/(g·min), see e.g. [3]. A step towards

146

Dielectric constant of skin and subcutaneous fat to assess fluid changes after cardiac surgery  

Microsoft Academic Search

The ability to objectively determine the degree of tissue edema and to monitor on-line fluid balance in critically ill patients would be a clinical benefit. In this prospective descriptive trial, we evaluated a new noninvasive method—dielectric constant of skin and subcutaneous fat (SSF)—in assessing fluid balance during cardiac surgery. The dielectric constant at the applied high radiofrequency is a direct

Liisa Petäjä; Jouni Nuutinen; Ari Uusaro; Tapani Lahtinen; Esko Ruokonen

2003-01-01

147

Assessing the impact of cerebral injury after cardiac surgery: will determining the mechanism reduce this injury?  

Microsoft Academic Search

Background. Central nervous system dysfunction continues to produce significant morbidity and associated mortality in patients undergoing cardiac surgery. Using a closed-chest canine cardiopulmonary bypass model, dogs underwent 2 h of hypothermic circulatory arrest (HCA) at 18°C, followed by resuscitation and recovery for 3 days. Animals were assessed functionally by a species-specific behavioral scale, histologically for patterns of selective neuronal necrosis,

William A Baumgartner; Peter L Walinsky; Jorge D Salazar; Elaine E Tseng; Malcolm V Brock; John R Doty; J. Mark Redmond; Mary E Blue; Maura A Goldsborough; Juan C Troncoso; Michael V Johnston

1999-01-01

148

Evaluation of optical imaging and spectroscopy approaches for cardiac tissue depth assessment  

SciTech Connect

NIR light scattering from ex vivo porcine cardiac tissue was investigated to understand how imaging or point measurement approaches may assist development of methods for tissue depth assessment. Our results indicate an increase of average image intensity as thickness increases up to approximately 2 mm. In a dual fiber spectroscopy configuration, sensitivity up to approximately 3 mm with an increase to 6 mm when spectral ratio between selected wavelengths was obtained. Preliminary Monte Carlo results provided reasonable fit to the experimental data.

Lin, B; Matthews, D; Chernomordik, V; Gandjbakhche, A; Lane, S; Demos, S G

2008-02-13

149

Pulmonary hypertension in systemic sclerosis determines cardiac autonomic dysfunction assessed by heart rate turbulence  

Microsoft Academic Search

There is limited data on heart rate turbulence (HRT) in systemic sclerosis (SSc) patients, potentially threatened with cardiac autonomic dysfunction. We performed 24-hour Holter monitoring for HRT assessment in 45 patients with SSc and 30 healthy controls. Abnormal HRT defined as turbulence onset (TO) ?0.0% and\\/or turbulence slope (TS)?2.5 ms\\/RR was found in 19 (42%) of SSc patients while not in

Piotr Bienias; Micha? Ciurzy?ski; Dariusz Korczak; Krzysztof Jankowski; Maria Gli?ska-Wielochowska; Danuta Liszewska-Pfejfer; Wies?aw Gli?ski; Piotr Pruszczyk

2010-01-01

150

Economic input\\/output analysis to aid life cycle assessment of electronics products  

Microsoft Academic Search

Economic input\\/output (EIO) analysis is a well established modelling framework for tracing the flows of inputs and outputs throughout an economy. It can aid life cycle analysis by providing a comprehensive framework for analyzing environmental costs, thereby eliminating the ad hoc boundary assumptions required in conventional life cycle analysis. We illustrate use of the EIO method with applications to electronics

E. Cobas; C. Hendrickson; L. Lave; F. McMichael

1995-01-01

151

Assessing satellite AOD based and WRF/CMAQ output PM2.5 estimators  

NASA Astrophysics Data System (ADS)

Fine particulate matter measurements (PM2.5) are essential for air quality monitoring and related public health; however, the shortage of reliable measurmennts constrains researchers to use other means for obtaining reliable estimates over large scales. In particular, model forecasters and satellite community use their respective products to develop ground particulate matter estimations but few experiments have explored how the remote sensing approaches compare to the high resolution models. . In this paper we focus on studying the performance of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Geostationary Operational Environmental Satellites (GOES) regression based estimates in comparison to more direct bias corrected outputs from the Community Multiscale Air Quality (CMAQ) model, We use a two-year dataset (2005-2006) and apply urban, season and hour filters to illustrate the agreement between estimated and in-situ measured fine particulate matter from the New York State Department of Environmental Conservation (NYSDEC). We first begin by analyzing the correspondence between ground aerosol optical depth (AOD) measurements from an AERONET (AErosol RObotic NETwork) Cimel sun/sky radiometer with both satellite and model products in one urban location; we show that satellite readings perform better than model outputs, especially during the summer (RMODIS>=0.65, RCMAQ>=0.37). This is a clear symptom of the difficulty in the models to properly model realistic optical properties. We then turn to a direct assessment of PM2.5 presenting individual comparisons between ground PM2.5 measurements with satellite/model predictions and demonstrate the higher accuracy from model estimations (RurbanMODIS >= 0.74, RurbanCMAQ >= 0.77; Rnon-urbanMODIS >= 0.48, Rnon-urbanCMAQ >= 0.78). In general, we find that the bias corrected CMAQ estimates are superior to satellite based estimators except at very high resolution. Finally, we show that when using both model and satellite approximations as separate estimators merged optimally, our product (PM2.5 average) becomes closer to real measurements with improved correlations (RAVE ~ 0.86) in urban areas during the summer.

Cordero, Lina; Wu, Yonghua; Gross, Barry M.; Moshary, Fred

2013-05-01

152

Physiologic Assessment of Coronary Artery Disease by Cardiac Computed Tomography  

PubMed Central

Coronary artery disease (CAD) remains the leading cause of death and morbidity worldwide. To date, diagnostic evaluation of patients with suspected CAD has relied upon the use of physiologic non-invasive testing by stress electrocardiography, echocardiography, myocardial perfusion imaging (MPI) and magnetic resonance imaging. Indeed, the importance of physiologic evaluation of CAD has been highlighted by large-scale randomized trials that demonstrate the propitious benefit of an integrated anatomic-physiologic evaluation method by performing lesion-specific ischemia assessment by fractional flow reserve (FFR)-widely considered the "gold" standard for ischemia assessment-at the time of invasive angiography. Coronary CT angiography (CCTA) has emerged as an attractive non-invasive test for anatomic illustration of the coronary arteries and atherosclerotic plaque. In a series of prospective multicenter trials, CCTA has been proven as having high diagnostic performance for stenosis detection as compared to invasive angiography. Nevertheless, CCTA evaluation of obstructive stenoses is prone to overestimation of severity and further, detection of stenoses by CCTA does not reliably determine the hemodynamic significance of the visualized lesions. Recently, a series of technological innovations have advanced the possibility of CCTA to enable physiologic evaluation of CAD, thereby creating the potential of this test to provide an integrated anatomic-physiologic assessment of CAD. These advances include rest-stress MPI by CCTA as well as the use of computational fluid dynamics to non-invasively calculate FFR from a typically acquired CCTA. The purpose of this review is to summarize the most recent data addressing these 2 physiologic methods of CAD evaluation by CCTA. PMID:23964289

Kochar, Minisha

2013-01-01

153

Effects of levosimendan/furosemide infusion on Plasma Brain Natriuretic Peptide, echocardiographic parameters and cardiac output in end-stage heart failure patients  

PubMed Central

Summary Background Acute decompensation heart failure (ADHF) remains a cause of hospitalization in patients with end-stage congestive HF. The administration of levosimendan in comparison with a standard therapy in CHF patients admitted for ADHF was analysed. Material/Methods Consecutive patients admitted for ADHF (NYHA class III–IV) were treated with levosimendan infusion 0.1 ?g/kg/min or with furosemide infusion 100–160 mg per day for 48 hours (control group). All subjects underwent determination of brain natriuretic peptide (BNP), non-invasive cardiac output (CO), and echocardiogram at baseline, at the end of therapy and 1 week after therapy. Results Seven patients admitted for 20 treatments in 16 months (age 66 years; mean admission/year 5.4) were treated with levosimendan and compared with 7 patients admitted for 15 treatments (age 69.1 years; mean admission/year 6.1). At the end of levosimendan therapy, BNP decreased (from 679.7±512.1 pg/ml to 554.2±407.6 pg/ml p=0.03), and 6MWT and LVEF improved (from 217.6±97.7 m to 372.2±90.4 m p=0.0001; from 22.8±9.1% to 25.4±9.8% p=0.05). Deceleration time, E/A, E/E’, TAPSE, pulmonary pressure and CO did not change significantly after levosimendan therapy and after 1 week. At follow-up, only 6-min WT and NYHA class showed a significant improvement (p=0.0001, p=0.001 respectively). The furosemide infusion reduced NYHA class and body weight (from 3.4±0.6 to 2.3±0.5 p=0.001; from 77.5±8.6 kg to 76±6.6 kg p=0.04), but impaired renal function (clearances from 56.3±21.9 ml/min to 41.2±10.1 ml/min p=0.04). Conclusions Treating end-stage CHF patients with levosimendan improved BNP and LVEF, but this effect disappeared after 1 week. The amelioration of 6MWT and NYHA class lasted longer after levosimendan infusion. PMID:21358614

Feola, Mauro; Lombardo, Enrico; Taglieri, Camillo; Vallauri, Paola; Piccolo, Salvatore; Valle, Roberto

2011-01-01

154

Cardiac activity in marine invertebrates in response to pollutants: Automated interpulse duration assessment  

SciTech Connect

The updated method of the Computer-Aided Physiological Monitoring (CAPMON) system was used to study the effects of copper exposure on cardiac activity in the shore crab (Carcinus maenas) and the common mussel (Mytilus edulis). This new Automated Interpulse Duration Assessment (AIDA) system measures the time interval between heart beats, and was found to be a more sensitive tool for evaluating cardiac responses to pollutant exposure than other techniques. In addition to information regarding heart rate, also obtained by the CAPMON system (as beats per minute), the new system enables frequency distribution analysis of interpulse duration. An experiment involving C. maenas examined the effects of short term (24 h) and chronic exposure (4 weeks) to copper concentrations 0, 0.2, 0.4, 0.6 and 0.8 mgl{sup {minus}1} Cu. Subsequent recovery (6 weeks) of cardiac activity was also examined. In a second experiment mussels were exposed to one of five copper concentrations (in the range of 0--0.1 mgl{sup {minus}1} Cu) and `normal` cardiac activity was compared with activity after copper exposure. A dose-response relationship was established between copper concentration and heart rate in crabs. The control group had the longest mean inter-pulse duration, and mean interpulse duration decreased in a concentration-dependent manner for the copper treatments, reflecting an increase in heart rate. Distribution of interpulse duration changed from a variable, rather wide distribution in control crabs, to a sharp-peaked normal distribution in exposed crabs. Results after 4 weeks exposure were not significantly different from those found after 24 h. Return to normal cardiac activity was evident after a 6 week `recovery` period. Results from the mussel experiment showed burst activity followed by a decline in heart rate in response to copper exposure.

Lundebye, A.K.; Curtis, T.; Depledge, M.H. [Univ. of Plymouth (United Kingdom)

1995-12-31

155

An optimized and simplified system of mouse embryonic stem cell cardiac differentiation for the assessment of differentiation modifiers.  

PubMed

Generating cardiomyocytes from embryonic stem cells is an important technique for understanding cardiovascular development, the origins of cardiovascular diseases and also for providing potential reagents for cardiac repair. Numerous methods have been published but often are technically challenging, complex, and are not easily adapted to assessment of specific gene contributions to cardiac myocyte differentiation. Here we report the development of an optimized protocol to induce the differentiation of mouse embryonic stem cells to cardiac myocytes that is simplified and easily adapted for genetic studies. Specifically, we made four critical findings that distinguish our protocol: 1) mouse embryonic stem cells cultured in media containing CHIR99021 and PD0325901 to maintain pluripotency will efficiently form embryoid bodies containing precardiac mesoderm when cultured in these factors at a reduced dosage, 2) low serum conditions promote cardiomyocyte differentiation and can be used in place of commercially prepared StemPro nutrient supplement, 3) the Wnt inhibitor Dkk-1 is dispensable for efficient cardiac differentiation and 4) tracking differentiation efficiency may be done with surface expression of PDGFR? alone. In addition, cardiac mesodermal precursors generated by this system can undergo lentiviral infection to manipulate the expression of specific target molecules to assess effects on cardiac myocyte differentiation and maturation. Using this approach, we assessed the effects of CHF1/Hey2 on cardiac myocyte differentiation, using both gain and loss of function. Overexpression of CHF1/Hey2 at the cardiac mesoderm stage had no apparent effect on cardiac differentiation, while knockdown of CHF1/Hey2 resulted in increased expression of atrial natriuretic factor and connexin 43, suggesting an alteration in the phenotype of the cardiomyocytes. In summary we have generated a detailed and simplified protocol for generating cardiomyocytes from mES cells that is optimized for investigating factors that affect cardiac differentiation. PMID:24667642

Hartman, Matthew E; Librande, Jason R; Medvedev, Ivan O; Ahmad, Rabiah N; Moussavi-Harami, Farid; Gupta, Pritha P; Chien, Wei-Ming; Chin, Michael T

2014-01-01

156

Computerized assessment of motion-contaminated calcified plaques in cardiac multidetector CT  

SciTech Connect

An automated method for evaluating the image quality of calcified plaques with respect to motion artifacts in noncontrast-enhanced cardiac computed tomography (CT) images is introduced. This method involves using linear regression (LR) and artificial neural network (ANN) regression models for predicting two patient-specific, region-of-interest-specific, reconstruction-specific and temporal phase-specific image quality indices. The first is a plaque motion index, which is derived from the actual trajectory of the calcified plaque and is represented on a continuous scale. The second is an assessability index, which reflects the degree to which a calcified plaque is affected by motion artifacts, and is represented on an ordinal five-point scale. Two sets of assessability indices were provided independently by two radiologists experienced in evaluating cardiac CT images. Inputs for the regression models were selected from 12 features characterizing the dynamic, morphological, and intensity-based properties of the calcified plaques. Whereas LR-velocity (LR-V) used only a single feature (three-dimensional velocity), the LR-multiple (LR-M) and ANN regression models used the same subset of these 12 features selected through stepwise regression. The regression models were parameterized and evaluated using a database of simulated calcified plaque images from the dynamic NCAT phantom involving nine heart rate/multi-sector gating combinations and 40 cardiac phases covering two cardiac cycles. Six calcified plaques were used for the plaque motion indices and three calcified plaques were used for both sets of assessability indices. In one configuration, images from the second cardiac cycle were used for feature selection and regression model parameterization, whereas images from the first cardiac cycle were used for testing. With this configuration, repeated measures concordance correlation coefficients (CCCs) and associated 95% confidence intervals for the LR-V, LR-M, and ANN were 0.817 [0.785, 0.848], 0.894 [0.869, 0.916], and 0.917 [0.892, 0.936] for the plaque motion indices. For the two sets of assessability indices, CCC values for the ANN model were 0.843 [0.791, 0.877] and 0.793 [0.747, 0.828]. These two CCC values were statistically greater than the CCC value of 0.689 [0.648, 0.727], which was obtained by comparing the two sets of assessability indices with each other. These preliminary results suggest that the variabilities of assessability indices provided by regression models can lie within the variabilities of the indices assigned by independent observers. Thus, the potential exists for using regression models and assessability indices for determining optimal phases for cardiac CT image interpretation.

King, Martin; Giger, Maryellen L.; Suzuki, Kenji; Bardo, Dianna M. E.; Greenberg, Brent; Lan Li; Pan Xiaochuan [Department of Radiology, Committee on Medical Physics, University of Chicago, Chicago, Illinois 60637 (United States)

2007-12-15

157

Indium-111 antimyosin scintigraphy to assess myocardial damage in patients with suspected myocarditis and cardiac rejection  

SciTech Connect

Indium-111 antimyosin scans were used to assess myocardial damage in patients with suspected myocarditis and cardiac transplant rejection. The calculation of a myocardium to lung ratio (AM index) to quantify antimyosin uptake was performed. AM index in normal subjects (n = 8) at 48 hr postinjection was 1.46 +/- 0.04. In patients with suspected myocarditis (16 studies in 13 patients), AM index was 2.0 +/- 0.5 (p less than 0.001); suggesting a considerable incidence of ongoing cell damage in this group, despite the small proportion of positive right ventricular endomyocardial biopsy (RVbx) (4/13). In patients studied after cardiac transplantation (37 studies in 17 patients), AM indexes correlated with RVbx. In patients with RVbx proven rejection (n = 14), AM index was 1.87 +/- 0.19 (p less than 0.001). In patients with RVbx showing infiltrates but not myocyte damage (n = 13), AM index was 1.80 +/- 0.27 (p = 0.02). In patients with normal RVbx (n = 10), AM index was 1.56 +/- 0.17 (p = NS versus controls; p = 0.001 versus those with positive RVbx). Calculated AM indexes correlated with graded visual analysis of the scans (r = 0.823; p = 0.001). Antimyosin scans are an appropriate method to assess myocardial damage in patients with suspected myocarditis and cardiac rejection.

Carrio, I.; Berna, L.; Ballester, M.; Estorch, M.; Obrador, D.; Cladellas, M.; Abadal, L.; Ginjaume, M.

1988-12-01

158

[A basis for application of cardiac contractility variability in the Evaluation and assessment of exercise and fitness].  

PubMed

Cardiac contractility variability (CCV) is a new concept which is introduced in the research field of cardiac contractility in recent years, that is to say, there are some disparities between cardiac contractilities when heart contracts. The changing signals of cardiac contractility contain a plenty of information on the cardiovascular function and disorder. In order to collect and analyze the message, we could quantitatively evaluate the tonicity and equilibrium of cardiac sympathetic nerve and parasympathetic nerve, and the effects of bio-molecular mechanism on the cardiovascular activities. By analyzing CCV, we could further understand the background of human being's heritage characteristics, nerve types, the adjusting mechanism, the molecular biology, and the adjustment of cardiac automatic nerve. With the development of the computing techniques, the digital signal processing method and its application in medical field, this analysis has been progressing greatly. By now, the assessment of CCV, just like the analysis of heart rate variability, is mainly via time domain and frequency domain analysis. CCV is one of the latest research fields in human cardiac signals being scarcely reported in the field of sports medicine; however, its research progresses are of important value for cardiac physiology and pathology in sports medicine and rehabilitation medicine. PMID:20649051

Bu, Bin; Wang, Aihua; Han, Haijun; Xiao, Shouzhong

2010-06-01

159

173 A generic method to assess the adequacy of individual maternal cardiac reserve to tolerate the demands of pregnancy and labour  

Microsoft Academic Search

IntroductionClinicians often feel apprehensive when managing pregnant patients with heart disease. To complement current evaluation, we have developed a new method of directly assessing the individual patient's cardiac functional reserve through stress testing. Pregnant mothers with and without heart disease were studied to test the hypothesis that pregnant cardiac patients who possess cardiac reserve equivalent to that of controls can

D Barker; N Lewis; G Mason; L B Tan

2011-01-01

160

A novel cardiac MR chamber volume model for mechanical dyssynchrony assessment  

NASA Astrophysics Data System (ADS)

A novel cardiac chamber volume model is proposed for the assessment of left ventricular mechanical dyssynchrony. The tool is potentially useful for assessment of regional cardiac function and identification of mechanical dyssynchrony on MRI. Dyssynchrony results typically from a contraction delay between one or more individual left ventricular segments, which in turn leads to inefficient ventricular function and ultimately heart failure. Cardiac resynchronization therapy has emerged as an electrical treatment of choice for heart failure patients with dyssynchrony. Prior MRI techniques have relied on assessments of actual cardiac wall changes either using standard cine MR images or specialized pulse sequences. In this abstract, we detail a semi-automated method that evaluates dyssynchrony based on segmental volumetric analysis of the left ventricular (LV) chamber as illustrated on standard cine MR images. Twelve sectors each were chosen for the basal and mid-ventricular slices and 8 sectors were chosen for apical slices for a total of 32 sectors. For each slice (i.e. basal, mid and apical), a systolic dyssynchrony index (SDI) was measured. SDI, a parameter used for 3D echocardiographic analysis of dyssynchrony, was defined as the corrected standard deviation of the time at which minimal volume is reached in each sector. The SDI measurement of a healthy volunteer was 3.54%. In a patient with acute myocardial infarction, the SDI measurements 10.98%, 16.57% and 1.41% for basal, mid-ventricular and apical LV slices, respectively. Based on published 3D echocardiogram reference threshold values, the patient's SDI corresponds to moderate basal dysfunction, severe mid-ventricular dysfunction, and normal apical LV function, which were confirmed on echocardiography. The LV chamber segmental volume analysis model and SDI is feasible using standard cine MR data and may provide more reliable assessment of patients with dyssynchrony especially if the LV myocardium is thin or if the MR images have spatial resolution insufficient for proper resolution of wall thickness-features problematic for dyssynchrony assessment using existing MR techniques.

Song, Ting; Fung, Maggie; Stainsby, Jeffrey A.; Hood, Maureen N.; Ho, Vincent B.

2009-02-01

161

A novel approach for assessing cardiac fibrosis using label-free second harmonic generation.  

PubMed

To determine whether second harmonic generation (SHG) can be used as a novel and improved label-free technique for detection of collagen deposition in the heart. To verify whether SHG will allow accurate quantification of altered collagen deposition in diseased hearts following hypertrophic remodelling. Minimally invasive transverse aortic banding (MTAB) of mouse hearts was used to generate a reproducible model of cardiac hypertrophy. Physiological and functional assessment of hypertrophic development was performed using echocardiography and post-mortem analysis of remodelled hearts. Cardiac fibroblasts were isolated from sham-operated and hypertrophied hearts and proliferation rates compared. Multi-photon laser scanning microscopy was used to capture both two-photon excited autofluorescence (TPEF) and SHG images simultaneously in two channels. TPEF images were subtracted from SHG images and the resulting signal intensities from ventricular tissue sections were calculated. Traditional picrosirius red staining was used to verify the suitability of the SHG application. MTAB surgery induced significant hypertrophic remodelling and increased cardiac fibroblast proliferation. A significant increase in the density of collagen fibres between hypertrophic and control tissues (p < 0.05) was evident using SHG. Similar increases and patterns of staining were observed using parallel traditional picrosirius red staining of collagen. Label-free SHG microscopy provides a new alternative method for quantifying collagen deposition in fibrotic hearts. PMID:23921804

Martin, Tamara P; Norris, Greg; McConnell, Gail; Currie, Susan

2013-12-01

162

Detection of multiple cardiac markers with an integrated acoustic platform for cardiovascular risk assessment.  

PubMed

This work describes the application of a newly emerged biosensing configuration incorporating a Surface Acoustic Wave device integrated with a multi-channel microfluidic module for the rapid and efficient analysis of cardiac markers. The examined cardiac markers of creatine kinase MB (CK-MB), cardiac reactive protein (CRP), D-dimer and pregnancy-associated plasma protein A (PAPP-A), comprise a group of both established and emerging heart disease proteins, that has never been probed before with any kind of biochip-related platform. The four markers were successfully detected; kinetics and affinity studies on their interactions with the surface immobilized antibodies are also presented. A concentration detection limit of less than 1 nM was achieved, with a dynamic range of more than two orders of magnitude, covering some of the pathological and healthy areas of interest. Mixtures of biomarkers applied to the device surface were used to prove the specificity of each binding event and investigate the microsystem's performance in the presence of complex fluids, towards future utilization with real samples. The simplicity and multiplexing ability of the integrated platform render the system ideal as a potential diagnostic tool for cardiovascular risk assessment, where simultaneous analysis of various protein markers is required. PMID:21704750

Mitsakakis, Konstantinos; Gizeli, Electra

2011-08-01

163

Radionuclide assessment of left ventricular diastolic filling in diabetes mellitus with and without cardiac autonomic neuropathy.  

PubMed

Indexes of left ventricular diastolic filling were measured by radionuclide ventriculography in 28 patients with insulin-dependent diabetes mellitus without evidence of ischemic heart disease. Six patients (21%) had abnormal diastolic filling and differed from diabetic patients with normal filling in their greater severity of cardiac autonomic neuropathy, assessed by noninvasive means, and their lower plasma norepinephrine levels in the supine (131.1 +/- 24.7 versus 356.2 +/- 58.4 pg/ml, p less than 0.01) and upright (224.9 +/- 47.8 versus 673.3 +/- 122.3 pg/ml, p less than 0.005) positions. The diabetic patients determined as having cardiac autonomic neuropathy (n = 15) had depressed left ventricular diastolic filling compared with subjects free of autonomic neuropathy, whether measured as the time to peak filling rate (154.2 +/- 12.0 versus 119.1 +/- 10.6 ms, p less than 0.05) or the time to peak filling rate normalized to the cardiac cycle length (24.3 +/- 2.2 versus 16.2 +/- 1.5%, p less than 0.01). Of the various tests of autonomic nervous system function, the strongest correlate of impaired diastolic filling was orthostasis, measured as the decrease in systolic blood pressure with standing (r = 0.584, p less than 0.001). Thus, in patients with diabetes mellitus, alterations in sympathetic nervous system activity are associated with abnormalities of left ventricular diastolic filling. PMID:3011872

Kahn, J K; Zola, B; Juni, J E; Vinik, A I

1986-06-01

164

On site assessment of cardiac function and neural regulation in amateur half marathon runners  

PubMed Central

Objective Strenuous exercise variably modifies cardiovascular function. Only few data are available on intermediate levels of effort. We therefore planned a study in order to address the hypothesis that a half marathon distance would result in transient changes of cardiac mechanics, neural regulation and biochemical profile suggestive of a complex, integrated adaptation. Methods We enrolled 35 amateur athletes (42±7?years). Supine and standing heart rate variability and a complete echocardiographic evaluation were assessed on site after the completion of a half marathon (postrace) and about 1?month after (baseline). Biochemical tests were also measured postrace. Results Compared to baseline, the postrace left ventricular end-diastolic volume was smaller, peak velocity of E wave was lower, peak velocity of A wave higher, and accordingly the E/A ratio lower. The postrace heart and respiratory rate were higher and variance of RR interval lower, together with a clear shift towards a sympathetic predominance in supine position and a preserved response to orthostasis. At baseline, athletes were characterised by a lower, although still predominant, sympathetic drive with a preserved physiological response to standing. Conclusions Immediately after a half marathon there are clear marks that an elevated sympathetic cardiac drive outlasts the performance, together with decreased left ventricular diastolic volumes and slight modifications of the left ventricular filling pattern without additional signs of diastolic dysfunction or indices of transient left or right ventricular systolic abnormalities. Furthermore, no biochemical indices of any permanent cardiac damage were found. PMID:25332775

Dalla Vecchia, Laura; Traversi, Egidio; Porta, Alberto; Lucini, Daniela; Pagani, Massimo

2014-01-01

165

A mobile phone-based care model for outpatient cardiac rehabilitation: the care assessment platform (CAP)  

PubMed Central

Background Cardiac rehabilitation programs offer effective means to prevent recurrence of a cardiac event, but poor uptake of current programs have been reported globally. Home based models are considered as a feasible alternative to avoid various barriers related to care centre based programs. This paper sets out the study design for a clinical trial seeking to test the hypothesis that these programs can be better and more efficiently supported with novel Information and Communication Technologies (ICT). Methods/Design We have integrated mobile phones and web services into a comprehensive home- based care model for outpatient cardiac rehabilitation. Mobile phones with a built-in accelerometer sensor are used to measure physical exercise and WellnessDiary software is used to collect information on patients' physiological risk factors and other health information. Video and teleconferencing are used for mentoring sessions aiming at behavioural modifications through goal setting. The mentors use web-portal to facilitate personal goal setting and to assess the progress of each patient in the program. Educational multimedia content are stored or transferred via messaging systems to the patients phone to be viewed on demand. We have designed a randomised controlled trial to compare the health outcomes and cost efficiency of the proposed model with a traditional community based rehabilitation program. The main outcome measure is adherence to physical exercise guidelines. Discussion The study will provide evidence on using mobile phones and web services for mentoring and self management in a home-based care model targeting sustainable behavioural modifications in cardiac rehabilitation patients. Trial registration The trial has been registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) with number ACTRN12609000251224. PMID:20109196

2010-01-01

166

ICT Expenditures and Education Outputs/Outcomes in Selected Developed Countries: An Assessment of Relative Efficiency  

ERIC Educational Resources Information Center

Purpose: The aim of the paper is to review some previous researches examining ICT efficiency and the impact of ICT on educational output/outcome as well as different conceptual and methodological issues related to performance measurement. Design/methodology/approach: This paper adopts a non-parametric methodology, i.e. data envelopment analysis…

Aristovnik, Aleksander

2013-01-01

167

Developing a genetic fuzzy system for risk assessment of mortality after cardiac surgery.  

PubMed

Cardiac events could be taken into account as the leading causes of death throughout the globe. Such events also trigger an undesirable increase in what treatment procedures cost. Despite the giant leaps in technological development in heart surgery, coronary surgery still carries the high risk of the mortality. Besides, there is still a long way ahead to accurately predict and assess the mortality risk. This study is an attempt to develop an expert system for the risk assessment of mortality following the cardiac surgery. The developed system involves three main steps. In the first step, a filtering feature selection method is applied to select the best features. In the second step, an ad hoc data-driven method is utilized to generate the preliminary fuzzy inference system. Finally, a hybrid optimization method is presented to select the optimum subset of the rules. The study relies on 1,811 samples to evaluate the diagnosis performance of the proposed system. The obtained classification accuracy is very promising with regard to other benchmark classification methods including binary logistic regression (LR) and multilayer perceptron neural network (MLP) with the same attributes. The developed system leads to 100% sensitivity and 84.7% specificity, while LR and MLP methods statistically come up with lower figures (65, 78.6 and 65%, 75.8%), respectively. Now, a fuzzy supportive tool can be potentially taken as an alternative for the current mortality risk assessment system that are applied in coronary surgeries, and are chiefly based on crisp database. PMID:25119238

Nouei, Mahyar Taghizadeh; Kamyad, Ali Vahidian; Sarzaeem, MahmoodReza; Ghazalbash, Somayeh

2014-10-01

168

Clinical Application of Cine-MRI in the Visual Assessment of Mitral Regurgitation Compared to Echocardiography and Cardiac Catheterization  

PubMed Central

Background Detecting and quantifying the severity of mitral regurgitation is essential for risk stratification and clinical decision-making regarding timing of surgery. Our objective was to assess specific visual parameters by cine-magnetic resonance imaging (MRI) in the determination of the severity of mitral regurgitation and to compare it to previously validated imaging modalities: echocardiography and cardiac ventriculography. Methods The study population consisted of 68 patients who underwent a cardiac MRI followed by an echocardiogram within a median time of 2.0 days and 49 of these patients who had a cardiac catheterization, median time of 2.0 days. The inter-rater agreement statistic (Kappa) was used to evaluate the agreement. Results There was moderate agreement between cine MRI and Doppler echocardiography in assessing mitral regurgitation severity, with a kappa value of 0.47, confidence interval (CI) 0.29–0.65. There was also fair agreement between cine MRI and cardiac catheterization with a kappa value of 0.36, CI of 0.17–0.55. Conclusion Cine MRI offers a reasonable alternative to both Doppler echocardiography and, to a lesser extent, cardiac catheterization for visually assessing the severity of mitral regurgitation with specific visual parameters during routine clinical cardiac MRI. PMID:22815751

Heitner, John; Bhumireddy, Geetha P.; Crowley, Anna Lisa; Weinsaft, Jonathan; Haq, Salman A.; Klem, Igor; Kim, Raymond J.; Jollis, James G.

2012-01-01

169

Construct, concurrent and discriminant validity of Type D personality in the general population: Associations with anxiety, depression, stress and cardiac output  

Microsoft Academic Search

The Type D personality, identified by high negative affectivity paired with high social inhibition, has been associated with a number of health-related outcomes in (mainly) cardiac populations. However, despite its prevalence in the health-related literature, how this personality construct fits within existing personality theory has not been directly tested. Using a sample of 134 healthy university students, this study examined

Siobhán Howard; Brian M. Hughes

2012-01-01

170

Construct, concurrent and discriminant validity of Type D personality in the general population: Associations with anxiety, depression, stress and cardiac output  

Microsoft Academic Search

The Type D personality, identified by high negative affectivity paired with high social inhibition, has been associated with a number of health-related outcomes in (mainly) cardiac populations. However, despite its prevalence in the health-related literature, how this personality construct fits within existing personality theory has not been directly tested. Using a sample of 134 healthy university students, this study examined

Siobhán Howard; Brian M. Hughes

2011-01-01

171

Quantitative assessment of myocardial blush grade in patients with coronary artery disease and in cardiac transplant recipients  

PubMed Central

Quantitative assessment of myocardial perfusion by myocardial blush grade (MBG) is an angiographic computer-assisted method to assess myocardial tissue-level reperfusion in patients with acute coronary syndromes and microvascular integrity in heart transplant recipients with suspected cardiac allograft vasculopathy. This review describes the ability of quantitative MBG as a simple, fast and cost effective modality for the prompt diagnosis of impaired microvascular integrity during routine cardiac catheterization. Herein, we summarize the existing evidence, its usefulness in the clinical routine, and compare this method to other techniques which can be used for the assessment of myocardial perfusion.

Hofmann, Nina Patricia; Dickhaus, Hartmut; Katus, Hugo A; Korosoglou, Grigorios

2014-01-01

172

Quantitative assessment of myocardial blush grade in patients with coronary artery disease and in cardiac transplant recipients.  

PubMed

Quantitative assessment of myocardial perfusion by myocardial blush grade (MBG) is an angiographic computer-assisted method to assess myocardial tissue-level reperfusion in patients with acute coronary syndromes and microvascular integrity in heart transplant recipients with suspected cardiac allograft vasculopathy. This review describes the ability of quantitative MBG as a simple, fast and cost effective modality for the prompt diagnosis of impaired microvascular integrity during routine cardiac catheterization. Herein, we summarize the existing evidence, its usefulness in the clinical routine, and compare this method to other techniques which can be used for the assessment of myocardial perfusion. PMID:25349655

Hofmann, Nina Patricia; Dickhaus, Hartmut; Katus, Hugo A; Korosoglou, Grigorios

2014-10-26

173

Assessing contributory risk using economic input-output life-cycle analysis.  

PubMed

The contribution of consumer purchases of non-essential products to environmental pollution is characterized. Purchase decisions by consumers induce a complex sequence of economy-wide production interactions that influence the production and consumption of chemicals and subsequent exposure and possible public health risks. An economic input-output life-cycle analysis (EIO-LCA) was used to link resource consumption and production by manufacturers to corresponding environmental impacts. Using the US Department of Commerce's input-output tables together with the US Environmental Protection Agency's Toxics Release Inventory and AIRData databases, the economy-wide air discharges resulting from purchases of household appliances, motor homes, and games and toys were quantified. The economic and environmental impacts generated from a hypothetical 10,000 US dollar purchase for selected consumer items were estimated. The analysis shows how purchases of seemingly benign consumer products increase the output of air pollutants along the supply chain and contribute to the potential risks associated with environmental chemical exposures to both consumers and non-consumers alike. PMID:16026022

Miller, Ian; Shelly, Michael; Jonmaire, Paul; Lee, Richard V; Harbison, Raymond D

2005-04-01

174

Abstract--Heart rate variability (HRV) measures have been used to assess autonomic cardiac regulation. The standard  

E-print Network

Abstract--Heart rate variability (HRV) measures have been used to assess autonomic cardiac. The HF peak, while promising, would require further studies. Keywords--Heart rate variability (HRV), electrocardiogram (ECG) I. INTRODUCTION Heart rate variability (HRV) has been used to assess the level of autonomic

175

Statistical Downscaling and Bias Correction of Climate Model Outputs for Climate Change Impact Assessment in the U.S. Northeast  

NASA Technical Reports Server (NTRS)

Statistical downscaling can be used to efficiently downscale a large number of General Circulation Model (GCM) outputs to a fine temporal and spatial scale. To facilitate regional impact assessments, this study statistically downscales (to 1/8deg spatial resolution) and corrects the bias of daily maximum and minimum temperature and daily precipitation data from six GCMs and four Regional Climate Models (RCMs) for the northeast United States (US) using the Statistical Downscaling and Bias Correction (SDBC) approach. Based on these downscaled data from multiple models, five extreme indices were analyzed for the future climate to quantify future changes of climate extremes. For a subset of models and indices, results based on raw and bias corrected model outputs for the present-day climate were compared with observations, which demonstrated that bias correction is important not only for GCM outputs, but also for RCM outputs. For future climate, bias correction led to a higher level of agreements among the models in predicting the magnitude and capturing the spatial pattern of the extreme climate indices. We found that the incorporation of dynamical downscaling as an intermediate step does not lead to considerable differences in the results of statistical downscaling for the study domain.

Ahmed, Kazi Farzan; Wang, Guiling; Silander, John; Wilson, Adam M.; Allen, Jenica M.; Horton, Radley; Anyah, Richard

2013-01-01

176

Assessment of catchment scale connectivity in different catchments using measured suspended sediment output  

NASA Astrophysics Data System (ADS)

Recent developments in hydrology and geomorphology include the connectivity principle, which describes how different elements in a landscape are connected and how water and matter moves between these elements. So far, studies on connectivity have been mainly of a conceptual nature and have been done on a small scale, while studies that map, quantitatively establish relations, and model water and sediment transport in connectivity are rare. In this study we established a relation between change in connectivity within four catchments and the time of year by using suspended sediment data. The data were collected for four catchments in Navarra, Spain of which two catchments are dominated by forest and pasture, while the other two catchments are dominated by agriculture and have no forest. Data were collected during a 13 year period; 4 samples were taken a day at 6 hour intervals which were mixed to obtain a daily average suspended sediment concentration. This was then converted into daily suspended sediment output using the measured total daily discharge. The effect of precipitation on the sediment output data was minimized by using an antecedent precipitation index (API), which consists of the precipitation of the current day added by the precipitation of the previous 14 days, where the influence of the previous days decays exponentially with time. The daily total suspended sediment output was divided by the API, to obtain a measure for sediment output independent of precipitation. This sediment output then serves as a measure for the connectivity within the catchment. The connectivity of the four catchments throughout the years will be compared to each other and we hypothesise that the two catchments dominated by forests and pastures will change only slightly throughout the year, whereas we expect to see large differences in connectivity in the two agricultural catchments. The agricultural catchments are likely to display a highly varying connectivity throughout the seasons due to changes in vegetation cover of the fields throughout the year, whereas daily variations will likely be small due to a slowly changing connectivity.

Masselink, Rens; Keesstra, Saskia; Seeger, Manuel

2014-05-01

177

Cardiac gated ventilation  

SciTech Connect

There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart.

Hanson, C.W. III [Hospital of the Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. Anesthesia; Hoffman, E.A. [Univ. of Iowa College of Medicine, Iowa City, IA (United States). Div. of Physiologic Imaging

1995-12-31

178

Cardiac gated ventilation  

NASA Astrophysics Data System (ADS)

There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. We evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50msec scan aperture. Multislice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. We observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a nonfailing model of the heart.

Hanson, C. William, III; Hoffman, Eric A.

1995-05-01

179

Approach to assessing fitness to drive in patients with cardiac and cognitive conditions  

PubMed Central

OBJECTIVE To help physicians become more comfortable assessing the fitness to drive of patients with complex cardiac and cognitive conditions. QUALITY OF EVIDENCE The approach described is based on the authors’ clinical practices, recommendations from the Third Canadian Consensus Conference on Diagnosis and Treatment of Dementia, and guidelines from the 2003 Canadian Cardiovascular Society Consensus Conference. MAIN MESSAGE When assessing fitness to drive in patients with multiple, complex health problems, physicians should divide conditions that might affect driving into acute intermittent (ie, not usually present on examination) and chronic persistent (ie, always present on examination) medical conditions. Physicians should address acute intermittent conditions first, to allow time for recovery from chronic persistent features that might be reversible. Decisions regarding fitness to drive in acute intermittent disorders are based on probability of recurrence; decisions in chronic persistent disorders are based on functional assessment. CONCLUSION Assessing fitness to drive is challenging at the best of times. When patients have multiple comorbidities, assessment becomes even more difficult. This article provides clinicians with systematic approaches to work through such complex cases. PMID:21075991

Molnar, Frank J.; Simpson, Christopher S.

2010-01-01

180

LVM Assessed by Echocardiography and Cardiac Magnetic Resonance, Cardiovascular Outcomes, and Medical Practice  

PubMed Central

We investigate three important areas related to the clinical use of LVM (LVM): accuracy of assessments by echocardiography and cardiac magnetic resonance (CMR), the ability to predict cardiovascular outcomes, and the comparative value of different indexing methods. The recommended formula for echocardiographic estimation of LVM uses linear measurements and is based on the assumption of the left ventricle as a prolate ellipsoid of revolution. CMR permits a modeling of the left ventricle free of cardiac geometric assumptions or acoustic window dependency, showing better accuracy and reproducibility. However, echocardiography has lower cost, easier availability, and better tolerability. From the Medline database, 26 longitudinal echocardiographic studies and 5 CMR studies, investigating LVM or LV hypertrophy as predictors of death or major cardiovascular outcomes, were identified. LVM and LV hypertrophy were reliable cardiovascular risk predictors using both modalities. However, no study directly compared the methods for the ability to predict events, agreement in hypertrophy classification, or performance in cardiovascular risk reclassification. Indexing LVM to BSA was the earliest normalization process used, but it seems to underestimate the prevalence of hypertrophy in obese and overweight subjects. Dividing LVM by height to 1.7 or 2.7 as allometric powers are the most promising normalization methods in terms of practicality and usefulness from a clinical ans scientific standpoints for scaling myocardial mass to body size. The measurement of LVM, calculation of LVMi, and classification for LVH should be standardized by scientific societies across measurement techniques and adopted by clinicians in risk stratification and therapeutic decision. PMID:22897998

Armstrong, Anderson C.; Gidding, Samuel; Gjesdal, Ola; Wu, Colin; Bluemke, David A; Lima, Joao A.

2012-01-01

181

Calcium antagonistic properties of nicardipine, a dihydropyridine derivative assessed in isolated cerebral arteries and cardiac muscle.  

PubMed

Calcium antagonistic properties of nicardipine (YC-93), a 1,4-dihydropyridine derivative, were studied in isolated cerebral artery and cardiac tissues of rabbits and dogs. Calcium antagonism was assessed in electrically stimulated rabbit basilar artery. Nicardipine at 10(-7) mol/l shifted to the right the dose-response curve for Ca of the phasic contraction evoked by electrical stimulation with an alternating current, and at higher concentration it reduced the maximum tension and slope of the dose-response curve. Nicardipine inhibited the augmented contraction produced by high K, k-strophanthin and 5-hydroxytryptamine. It also caused dose-dependent inhibition of 45Ca uptake enhanced by 80 mmol/l K in dog basilar artery, and had a slight effect on the resting 45Ca uptake. In rabbit basilar artery treated with saponin, nicardipine in a dose of 10(-5) mol/l had no apparent effect on the increase in tension induced by excess Ca. Nicardipine had negative inotropic and chronotropic actions. These results suggest that nicardipine, like nifedipine, has a relative high vascular selectivity, and primarily acts by inhibiting Ca influx through the plasma membrane of vascular and cardiac tissues. PMID:4015735

Nakayama, K; Kurihara, J; Miyajima, Y; Ishii, K; Kato, H

1985-01-01

182

A history of the role of the hERG channel in cardiac risk assessment.  

PubMed

The human ether-a-go-go-related gene (hERG, Kv11.1) K(+) channel plays an important role in cardiac repolarization. Following its cloning and expression it was established that inhibition of this channel was the molecular mechanism for many non-antiarrhythmic drugs that produce torsades de pointes associated with QT prolongation. Therefore the study of in vitro drug-hERG interactions has become an important part of modern safety pharmacology. Manual and automated patch clamp electrophysiology, in silico modeling, and hERG trafficking assays have been developed to aid in this study. The correlation between in vitro hERG IC50, drug exposure, QT prolongation in the thorough QT clinical trial and risk of TdP has greatly reduced drug withdrawals due to TdP. However a significant association with Type 1 errors in particular remains and may have a negative impact on drug development. Combining hERG data with other non-clinical and clinical markers of proarrhythmia will increase the specificity and sensitivity of cardiac risk assessment. hERG will continue to play an important role in drug development and safety pharmacology in the future. PMID:23538024

Rampe, David; Brown, Arthur M

2013-01-01

183

What is the utility of preoperative frailty assessment for risk stratification in cardiac surgery?  

PubMed Central

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether frailty scoring can be used either separately or combined with conventional risk scores to predict survival and complications. Five hundred and thirty-five papers were found using the reported search, of which nine cohort studies represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. There is a paucity of evidence, as advanced age is a criterion for exclusion in most randomized controlled trials. Conventional models of risk following cardiac surgery are not calibrated to accurately predict the outcomes in the elderly and do not currently include frailty parameters. There is no universally accepted definition for frailty, but it is described as a physiological decline in multiple organ systems, decreasing a patient's capacity to withstand the stresses of surgery and disease. Frailty is manifest clinically as deficits in functional capacity, such as slow ambulation and impairments in the activities of daily living (ADL). Analysis of predictive models using area under receiver operating curves (AUC) suggested only a modest benefit by adding gait speed to a Society of Thoracic Surgeons (STS score)-Predicted Risk of Mortality or Major Morbidity (PROM) risk score (AUC 0.04 mean difference). However, a specialist frailty assessment tool named FORECAST was found to be superior at predicting adverse outcomes at 1 year compared with either EuroSCORE or STS score (AUC 0.09 mean difference). However, risk models incorporating frailty parameters require further validation and have not been widely adopted. Routine collection of objective frailty measures such as 5-metre walk time and ADL assessment will help to provide data to develop new risk-assessment models to facilitate risk stratification and clinical decision-making in elderly patients. Based on the best evidence currently available, we conclude that frailty is an independent predictor of adverse outcome following cardiac surgery or transcatheter aortic valve implantation, increasing the risk of mortality 2- to 4-fold compared with non-frail patients. PMID:23667068

Bagnall, Nigel Mark; Faiz, Omar; Darzi, Ara; Athanasiou, Thanos

2013-01-01

184

3D left ventricular extracellular volume fraction by low-radiation dose cardiac CT: Assessment of interstitial myocardial fibrosis  

PubMed Central

Background Myocardial fibrosis leads to impaired cardiac function and events. Extracellular volume fraction (ECV) assessed with an iodinated contrast agent and measured by cardiac CT may be a useful noninvasive marker of fibrosis. Objective The purpose of this study was to develop and evaluate a 3-dimensional (3D) ECV calculation toolkit (ECVTK) for ECV determination by cardiac CT. Methods Twenty-four subjects (10 systolic heart failure, age, 60 ± 17 years; 5 diastolic failure, age 56 ± 20 years; 9 matched healthy subjects, age 59 ± 7 years) were evaluated. Cardiac CT examinations were done on a 320-multidetector CT scanner before and after 130 mL of iopamidol (Isovue-370; Bracco Diagnostics, Plainsboro, NJ, USA) was administered. A calcium score type sequence was performed before and 7 minutes after contrast with single gantry rotation during 1 breath hold and single cardiac phase acquisition. ECV was calculated as (?HUmyocardium/?HUblood) × (1 ? Hct) where Hct is the hematocrit, and ?HU is the change in Hounsfield unit attenuation = HUafter iodine ? HUbefore iodine. Cardiac magnetic resonance imaging was performed to assess myocardial structure and function. Results Mean 3D ECV values were significantly higher in the subjects with systolic heart failure than in healthy subjects and subjects with diastolic heart failure (mean, 41% ± 6%, 33% ± 2%, and 35% ± 5%, respectively; P = 0.02). Interobserver and intraobserver agreements were excellent for myocardial, blood pool, and ECV (intraclass correlation coefficient, >0.90 for all). Higher 3D ECV by cardiac CT was associated with reduced systolic circumferential strain, greater end-diastolic and -systolic volumes, and lower ejection fraction (r = 0.70, r = 0.60, r = 0.73, and r = ?0.68, respectively; all P < 0.001). Conclusion 3D ECV by cardiac CT can be performed with ECVTK. We demonstrated increased ECV in subjects with systolic heart failure compared with healthy subjects. Cardiac CT results also showed good correlation with important functional heart biomarkers, suggesting the potential for myocardial tissue characterization with the use of 3D ECV by cardiac CT. This trial is registered at www.ClinicalTrials.gov as NCT01160471. PMID:23333188

Nacif, Marcelo Souto; Liu, Yixun; Yao, Jianhua; Liu, Songtao; Sibley, Christopher T.; Summers, Ronald M.; Bluemke, David A.

2014-01-01

185

Image Processing Techniques for Assessing Contractility in Isolated Adult Cardiac Myocytes  

PubMed Central

We describe a computational framework for the comprehensive assessment of contractile responses of enzymatically dissociated adult cardiac myocytes. The proposed methodology comprises the following stages: digital video recording of the contracting cell, edge preserving total variation-based image smoothing, segmentation of the smoothed images, contour extraction from the segmented images, shape representation by Fourier descriptors, and contractility assessment. The different stages are variants of mathematically sound and computationally robust algorithms very well established in the image processing community. The physiologic application of the methodology is evaluated by assessing overall contraction in enzymatically dissociated adult rat cardiocytes. Our results demonstrate the effectiveness of the proposed approach in characterizing the true, two-dimensional, “shortening” in the contraction process of adult cardiocytes. We compare the performance of the proposed method to that of a popular edge detection system in the literature. The proposed method not only provides a more comprehensive assessment of the myocyte contraction process but also can potentially eliminate historical concerns and sources of errors caused by myocyte rotation or translation during contraction. Furthermore, the versatility of the image processing techniques makes the method suitable for determining myocyte shortening in cells that usually bend or move during contraction. The proposed method can be utilized to evaluate changes in contractile behavior resulting from drug intervention, disease modeling, transgeneity, or other common applications to mammalian cardiocytes. PMID:20224633

Bazan, Carlos; Barba, David Torres; Blomgren, Peter; Paolini, Paul

2009-01-01

186

Optical assessment of the cardiac rhythm of contracting cardiomyocytes in vitro and a pulsating heart in vivo for pharmacological screening  

PubMed Central

Our quest in the pathogenesis and therapies targeting human heart diseases requires assessment of the contractile dynamics of cardiac models of varied complexity, such as isolated cardiomyocytes and the heart of a model animal. It is hence beneficial to have an integral means that can interrogate both cardiomyocytes in vitro and a heart in vivo. Herein we report an application of dual-beam optical reflectometry to determine noninvasively the rhythm of two representative cardiac models–chick embryonic cardiomyocytes and the heart of zebrafish. We probed self-beating cardiomyocytes and revealed the temporally varying contractile frequency with a short-time Fourier transform. Our unique dual-beam setup uniquely records the atrial and ventricular pulsations of zebrafish simultaneously. To minimize the cross talk between signals associated with atrial and ventricular chambers, we particularly modulated the two probe beams at distinct frequencies and extracted the signals specific to individual cardiac chambers with phase-sensitive detection. With this setup, we determined the atrio-ventricular interval, a parameter that is manifested by the electrical conduction from the atrium to the ventricle. To demonstrate pharmacological applications, we characterized zebrafish treated with various cardioactive and cardiotoxic drugs, and identified abnormal cardiac rhythms and atrioventricular (AV) blocks of varied degree. In light of its potential capability to assess cardiac models both in vitro and in vivo and to screen drugs with cardioactivity or toxicity, we expect this approach to have broad applications ranging from cardiopharmacology to developmental biology. PMID:24877019

Lai, Yu-Cheng; Chang, Wei-Tien; Lin, Kuen-You; Liau, Ian

2014-01-01

187

Cardiac CT for the assessment of chest pain: imaging techniques and clinical results.  

PubMed

Immediate and efficient risk stratification and management of patients with acute chest pain in the emergency department is challenging. Traditional management of these patients includes serial ECG, laboratory tests and further on radionuclide perfusion imaging or ECG treadmill testing. Due to the advances of multi-detector CT technology, dedicated coronary CT angiography provides the potential to rapidly and reliably diagnose or exclude acute coronary artery disease. Life-threatening causes of chest pain, such as aortic dissection and pulmonary embolism can simultaneously be assessed with a single scan, sometimes referred to as "triple rule out" scan. With appropriate patient selection, cardiac CT can accurately diagnose heart disease or other sources of chest pain, markedly decrease health care costs, and reliably predict clinical outcomes. This article reviews imaging techniques and clinical results for CT been used to evaluate patients with chest pain entering the emergency department. PMID:21798681

Becker, Hans-Christoph; Johnson, Thorsten

2012-12-01

188

Scintigraphic assessment of cardiac adrenergic innervation in patients with essential hypertension  

SciTech Connect

To assess the regional cardiac adrenergic innervation in patients with essential hypertension (EHT), simultaneous iodine-123 metaiodobenzylguanidine ((123I)MIBG) and thallium-201 (201Tl) myocardial imagings were performed in five patients with EHT, seven patients with hypertrophic cardiomyopathy (HCM), and seven normal subjects. Short axial images at rest were divided into five segments: anterior, septal, posterior, lateral, and apical segments. Percent regional uptake (%RU) of 201Tl except the septal segment in patients with EHT showed no significant difference. However, the %RU of (123I)MIBG at posterior, lateral, and apical segments was significantly lower than that at anterior and septal segments in EHT. This intraimage heterogeneity of (123I)MIBG was also observed in HCM. These results suggest that there is a difference in regional adrenergic innervation of the left ventricle with myocardial hypertrophy.

Fujiwara, Y.; Hamada, M.; Shigematsu, Y.; Sumimoto, T.; Hamamoto, K.; Hiwada, K. (2nd Department of Internal Medicine, Ehime University School of Medicine (Japan))

1991-01-01

189

Global assessment of agreement among streamflow projections using CMIP5 model outputs  

NASA Astrophysics Data System (ADS)

Runoff outputs from 11 atmosphere-ocean general circulation models (AOGCMs) participating in the fifth phase of Coupled Model Intercomparison Project were used to evaluate the changes in streamflow and agreement among AOGCMs at the end of 21st century. Under the highest emission scenario (Representative Concentration Pathways (RCP) 8.5), high flow is projected to increase in northern high latitudes of Eurasia and North America, Asia, and eastern Africa, while mean and low flows are both projected to decrease in Europe, Middle East, southwestern United States, and Central America. Projected changes under RCP4.5 show similar spatial distribution but with lower magnitude. The model spread of projected changes, however, is found to be large under both scenarios. Bootstrapped Mann-Whitney-Wilcoxon U test revealed that projected changes of streamflow regimes are statistically not significant in 8-32% (19-59%) of the world under RCP8.5 (RCP4.5). The model agreement on projected increase or decrease in mean and high flows is stronger under RCP8.5 than that under RCP4.5. On the other hand, the projected changes in low flow are robust in both scenarios with strong model agreement. In ˜7% (4%) of the world, high flow is projected to increase and low flow is projected to decrease, whereas in ˜29% (13%) all mean, high, and low flows are projected to increase under RCP8.5 (RCP4.5).

Koirala, Sujan; Hirabayashi, Yukiko; Mahendran, Roobavannan; Kanae, Shinjiro

2014-05-01

190

Interaction between resting pulmonary ventilation function and cardiac autonomic function assessed by heart rate variability in young adults  

Microsoft Academic Search

An association between ambient air pollution and reduced cardiac autonomic function assessed by heart rate variability (HRV) mainly in elderly persons has been suggested by a number of epide- miological studies, but the link between the HRV and pulmonary function in humans remains un- known although such air pollution should primarily affect pulmonary function. To clarify this link, pulmonary ventilation

Tomoko KUROSAWA; Toyoto IWATA; Miwako DAKEISHI; Tomoko OHNO; Mikako TSUKADA; Katsuyuki MURATA

2007-01-01

191

Relative indicators and relational charts for comparative assessment of publication output and citation impact  

Microsoft Academic Search

Cross-field comparison ofscientometric indicators\\u000a1 is severely hindered by the differences in publication and citation habits of science fields. However, relating publication and citation indicators to proper field-specific reference standards,relative indicators can be built, which may prove rather useful in the comparative assessment of scientists, groups, institutions or countries. The use ofrelational charts in displaying the indicators broadens the scope

A. Schubert; T. Braun

1986-01-01

192

Assessment of Cardiac Involvement in Myotonic Muscular Dystrophy by T1 Mapping on Magnetic Resonance Imaging  

PubMed Central

Background Patients with DM are at risk for atrioventricular block and left ventricular (LV) dysfunction. Non-invasive detection of diffuse myocardial fibrosis may improve disease management in this population. Objective Our aim was to define functional and post-contrast myocardial T1 time cardiac magnetic resonance (CMR) characteristics in myotonic muscular dystrophy (DM) patients. Methods Thirty-three DM patients (24 with type 1 and 9 with type 2) and 13 healthy volunteers underwent CMR for assessment of LV indices and evaluation of diffuse myocardial fibrosis by T1 mapping. The association of myocardial T1 time to ECG abnormalities and LV indices were examined among DM patients. Results DM patients had lower end-diastolic volume index (68.9 vs. 60.3 ml/m2, p=0.045), cardiac index (2.7 vs. 2.33 L/min/m2, p=0.005) and shorter myocardial T1time (394.5 vs. 441.4 ms, p<0.0001), compared to control subjects. Among DM patients, there was a positive association between higher T1 time and LV mass index (2.2 ms longer per gm/m2, p=0.006), LV end-diastolic volume index (1.3 ms longer per ml/m2, p=0.026), filtered QRS duration (1.2 ms longer per unit, p=0.005) and low-amplitude (<40mcV) late-potential duration (0.9 ms longer per unit, p=0.01). Using multivariate random effects regression, each 10 ms increase in myocardial T1 time of type 1 DM patients was independently associated with 1.3 ms increase in longitudinal PR and QRS intervals during follow-up. Conclusion DM is associated with structural alterations on CMR. Post-contrast myocardial T1 time was shorter in DM patients than controls likely reflecting the presence of diffuse myocardial fibrosis. PMID:22710483

Turkbey, Evrim B.; Gai, Neville; Lima, Joao A. C.; van der Geest, Rob J.; Wagner, Kathryn R.; Tomaselli, Gordon F.; Bluemke, David A.; Nazarian, Saman

2012-01-01

193

Evaluation of heart fatty acid–binding protein as a rapid indicator for assessment of myocardial damage in pediatric cardiac surgery  

Microsoft Academic Search

ObjectivesPerioperative myocardial damage is a major determinant of postoperative cardiac dysfunction for congenital heart disease. Heart fatty acid–binding protein is reported to be a rapid marker of perioperative myocardial damage that peaks earlier than creatine kinase isoenzyme MB or cardiac troponin T in adults. The objective of this study was to assess the suitability of using serum concentrations of heart

Tomomi Hasegawa; Naoki Yoshimura; Shigeteru Oka; Yoshio Ootaki; Yoshiya Toyoda; Masahiro Yamaguchi

2004-01-01

194

Assessment of Global Cardiac Function in MSCT Imaging Using Fuzzy Connectedness Segmentation  

E-print Network

and with a high spatial resolution, 3D dynamic images of cardiac walls and cavities and of coronary ves- sels global 3D quantitative parameters are extracted to describe the left cardiac func- tion. Several MRI [10]. Multi-agent approaches have also been considered for the analysis of brain images [11

Paris-Sud XI, Université de

195

CT measurement of coronary calcium mass: impact on global cardiac risk assessment  

Microsoft Academic Search

Coronary calcium mass percentiles can be derived from electron beam CT as well as from multidetector-row CT of all manufacturers. Coronary calcium mass may serve as a more individualized substitute for age for cardiac risk stratification. The aim was to investigate the potential impact of CT coronary calcium mass quantification on cardiac risk stratification using an adjusted Framingham score. Standardized

Christoph R. Becker; Amal Majeed; Alexander Crispin; Andreas Knez; U. Joseph Schoepf; Peter Boekstegers; Gerhard Steinbeck; Maximilian F. Reiser

2005-01-01

196

Contractile reserve assessed by dobutamine test identifies super-responders to cardiac resynchronization therapy  

PubMed Central

Introduction In this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker. Material and methods The study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (?WMSI) and ?LVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation. Results A total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ?WMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ?EF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ?WMSI ? 0.7 and ? 14% for ?EF are the best discriminators for a super-response. Patients with ?WMSI ? 0.7 and ?EF ? 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up. Conclusions Contractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT.

Milasinovic, Goran; Angelkov, Lazar; Ristic, Velibor; Tomovic, Milosav; Jurcevic, Ruzica; Otasevic, Petar

2014-01-01

197

Wearable seismocardiography: towards a beat-by-beat assessment of cardiac mechanics in ambulant subjects.  

PubMed

Seismocardiogram (SCG) is the measure of the micro-vibrations produced by the heart contraction and blood ejection into the vascular tree. Over time, a large body of evidence has been collected on the ability of SCG to reflect cardiac mechanical events such as opening and closure of mitral and aortic valves, atrial filling and point of maximal aortic blood ejection. We recently developed a smart garment, named MagIC-SCG, that allows the monitoring of SCG, electrocardiogram (ECG) and respiration out of the laboratory setting in ambulant subjects. The present pilot study illustrates the results of two different experiments performed to obtain a first evaluation on whether a dynamical assessment of indexes of cardiac mechanics can be obtained from SCG recordings obtained by MagIC-SCG. In the first experiment, we evaluated the consistency of the estimates of two indexes of cardiac contractility, the pre-ejection period, PEP, and the left ventricular ejection time, LVET. This was done in the lab, by reproducing an experimental protocol well known in literature, so that our measures derived from SCG could have been compared with PEP and LVET reference values obtained by traditional techniques. Six healthy subjects worn MagIC-SCG while assuming two different postures (supine and standing); PEP was estimated as the time interval between the Q wave in ECG and the SCG wave corresponding to the opening of aortic valve; LVET was the time interval between the SCG waves corresponding to the opening and closure of the aortic valve. The shift from supine to standing posture produced a significant increase in PEP and PEP/LVET ratio, a reduction in LVET and a concomitant rise in the LF/HF ratio in the RR interval (RRI) power spectrum. These results are in line with data available in literature thus providing a first support to the validity of our estimates. In the second experiment, we evaluated in one subject the feasibility of the beat-by-beat assessment of LVET during spontaneous behavior. The subject was continuously monitored by the smart garment from 8 am to 8 pm during a workday. From the whole recording, three data segments were selected: while the subject was traveling to work (M1), during work in the office (O) and while traveling back home (M2). LVET was estimated on a beat-by-beat basis from SCG and the RRI influence was removed by regression analysis. The LVET series displayed marked beat-by-beat fluctuations at the respiratory frequency. The amplitude of these fluctuations changed in the three periods and was lower when the LF/HF RRI power ratio was higher, at O, thus suggesting a possible influence of the autonomic nervous system on LVET short-term variability. To the best of our knowledge this case report provides for the first time a representation of the beat-by-beat dynamics of a systolic time interval during daily activity. The statistical characterization of these findings remains to be explored on a larger population. PMID:23664242

Di Rienzo, M; Vaini, E; Castiglioni, P; Merati, G; Meriggi, P; Parati, G; Faini, A; Rizzo, F

2013-11-01

198

Cardiac risk assessment before the use of stimulant medications in children and youth.  

PubMed

Regulatory decisions and scientific statements regarding the management of attention-deficit hyperactivity disorder (ADHD) raise questions about the safety of medications and the appropriate pretreatment evaluation to determine suitability for treatment with medication. This is particularly true in the setting of known structural or functional heart disease. The present paper reviews the available data, including peer-reviewed literature, data from the United States Food and Drug Administration Web site on reported adverse reactions in children using stimulant medication, and Health Canada data on the same problem. A consensus-based guideline on appropriate assessment is provided, based on input from members of the Canadian Paediatric Society, the Canadian Cardiovascular Society and the Canadian Academy of Child and Adolescent Psychiatry, with specific expertise and knowledge in the areas of both ADHD and paediatric cardiology. The present statement advocates a thorough history and physical examination before starting stimulant medications, with an emphasis on the identification of risk factors for sudden death, but does not routinely recommend electrocardiographic screening or cardiac sub-specialist consultation unless indicated by history or physical examination findings. A checklist for identifying children who are potentially at risk of sudden death (independent of ADHD or medications used to treat it) is provided. Although recommendations are based on the best evidence currently available, the committee further agrees that more research on this subject is necessary to optimize the approach to this common clinical scenario. PMID:21037835

Bélanger, S A; Warren, A E; Hamilton, R M; Gray, C; Gow, R M; Sanatani, S; Côté, J M; Frcpc, J Lougheed; Leblanc, J; Martin, S; Miles, B; Mitchell, C; Gorman, D A; Weiss, M; Schachar, R

2009-11-01

199

Preoperative levosimendan decreases mortality and the development of low cardiac output in high-risk patients with severe left ventricular dysfunction undergoing coronary artery bypass grafting with cardiopulmonary bypass  

PubMed Central

BACKGROUND: The calcium sensitizer levosimendan has been used in cardiac surgery for the treatment of postoperative low cardiac output syndrome (LCOS) and difficult weaning from cardiopulmonary bypass (CPB). OBJECTIVES: To evaluate the effects of preoperative treatment with levosimendan on 30-day mortality, the risk of developing LCOS and the requirement for inotropes, vasopressors and intra-aortic balloon pumps in patients with severe left ventricular dysfunction. METHODS: Patient with severe left ventricular dysfunction and an ejection fraction <25% undergoing coronary artery bypass grafting with CPB were admitted 24 h before surgery and were randomly assigned to receive levosimendan (loading dose 10 ?g/kg followed by a 23 h continuous infusion of 0.1?g/kg/min) or a placebo. RESULTS: From December 1, 2002 to June 1, 2008, a total of 252 patients were enrolled (127 in the levosimendan group and 125 in the control group). Individuals treated with levosimendan exhibited a lower incidence of complicated weaning from CPB (2.4% versus 9.6%; P<0.05), decreased mortality (3.9% versus 12.8%; P<0.05) and a lower incidence of LCOS (7.1% versus 20.8%; P<0.05) compared with the control group. The levosimendan group also had a lower requirement for inotropes (7.9% versus 58.4%; P<0.05), vasopressors (14.2% versus 45.6%; P<0.05) and intra-aortic balloon pumps (6.3% versus 30.4%; P<0.05). CONCLUSION: Patients with severe left ventricle dysfunction (ejection fraction <25%) undergoing coronary artery bypass grafting with CPB who were pretreated with levosimendan exhibited lower mortality, a decreased risk for developing LCOS and a reduced requirement for inotropes, vasopressors and intra-aortic balloon pumps. Studies with a larger number of patients are required to confirm whether these findings represent a new strategy to reduce the operative risk in this high-risk patient population. PMID:23620700

Levin, Ricardo; Degrange, Marcela; Del Mazo, Carlos; Tanus, Eduardo; Porcile, Rafael

2012-01-01

200

Implementation of the ACC\\/AHA Guidelines for Preoperative Cardiac Risk Assessment in a General Medicine Preoperative Clinic: Improving Efficiency and Preserving Outcomes  

Microsoft Academic Search

Background: The American College of Cardiology\\/American Heart Association (ACC\\/AHA) publishes recommendations for cardiac assessment of patients undergoing noncardiac surgery with the intent of promoting evidence-based, efficient preoperative screening and management. We sought to study the impact of guideline implementation for cardiac risk assessment in a general internal medicine preoperative clinic. Methods: The study was an observational cohort study of consecutive

Yassar Almanaseer; Debabrata Mukherjee; Eva M. Kline-Rogers; Sean K. Kesterson; Seema S. Sonnad; Bruce Rogers; Dean Smith; Scott Furney; Robert Ernst; Jane McCort; Kim A. Eagle

2005-01-01

201

Assessment of cardiac and pulmonary function in children with juvenile idiopathic arthritis  

Microsoft Academic Search

Juvenile idiopathic arthritis (JIA) is the most common rheumatologic disorder of childhood. It is a group of diseases characterized\\u000a by chronic synovitis and associated with many extra-articular manifestations including cardiac and pulmonary involvement.\\u000a Cardiac involvement as pericarditis, myocarditis and valvular disease is common in JIA. There are, however, few descriptions\\u000a concerning systolic and diastolic functions of the left ventricle (LV)

Eman A. M. Alkady; Hatem A. R. Helmy; Aliaë A. R. Mohamed-Hussein

202

A novel quantitative method for diabetic cardiac autonomic neuropathy assessment in type 1 diabetic mice.  

PubMed

In this work, we used a sensitive and noninvasive computational method to assess diabetic cardiovascular autonomic neuropathy (DCAN) from pulse oximeter (photoplethysmographic; PPG) recordings from mice. The method, which could be easily applied to humans, is based on principal dynamic mode (PDM) analysis of heart rate variability (HRV). Unlike the power spectral density, PDM has been shown to be able to separately identify the activities of the parasympathetic and sympathetic nervous systems without pharmacological intervention. HRV parameters were measured by processing PPG signals from conscious 1.5- to 5-month-old C57/BL6 control mice and in Akita mice, a model of insulin-dependent type 1 diabetes, and compared with the gold-standard Western blot and immunohistochemical analyses. The PDM results indicate significant cardiac autonomic impairment in the diabetic mice in comparison to the controls. When tail-cuff PPG recordings were collected and analyzed starting from 1.5 months of age in both C57/Bl6 controls and Akita mice, onset of DCAN was seen at 3 months in the Akita mice, which persisted up to the termination of the recording at 5 months. Western blot and immunohistochemical analyses also showed a reduction in nerve density in Akita mice at 3 and 4 months as compared to the control mice, thus, corroborating our PDM data analysis of HRV records. Western blot analysis of autonomic nerve proteins corroborated the PPG-based HRV analysis via the PDM approach. In contrast, traditional HRV analysis (based on either the power spectral density or time-domain measures) failed to detect the nerve rarefaction. PMID:25097056

Chon, Ki H; Yang, Bufan; Posada-Quintero, Hugo F; Siu, Kin L; Rolle, Marsha; Brink, Peter; Birzgalis, Aija; Moore, Leon C

2014-11-01

203

Continuous assessment and improvement in quality of care. A model from the Department of Veterans Affairs Cardiac Surgery.  

PubMed Central

OBJECTIVE: The authors organized the Department of Veterans Affairs (VA) Continuous Improvement in Cardiac Surgery Study (CICSS) to provide risk-adjusted outcome data for the continuous assessment and improvement of quality of care for all patients undergoing cardiac surgery in the VA. BACKGROUND: The use of risk-adjusted outcomes to monitor quality of health care has the potential advantage over consensus-derived standards of being free of preconceived biases about how health care should be provided. Monitoring outcomes of all health care episodes, as opposed to review of selected cases (e.g., adverse outcomes), has the advantages of greater statistical power, the opportunity to compare processes of care between good and bad outcomes, and the positive psychology of treating all providers equally. These two concepts, together with a pre-existing peer committee (the VA Cardiac Surgery Consultants Committee) to review, interpret, and act on the risk-adjusted outcome data, form the primary design considerations for CICSS. METHODS: Patient-level risk and outcome (operative mortality and morbidity) data are collected prospectively on each of the approximately 7000 patients undergoing cardiac surgery in the VA each year. These outcomes, adjusted for patient risk using logistic regression, are provided every 6 months to each cardiac surgery program and to a national peer review committee for internal and external quality assessment and improvement. RESULTS: For the most recent 12-month period with complete data collection, observed-to-expected (O/E) ratios ranged from 0.2 to 2.2, with eight centers falling outside of the 90% confidence limits for an O/E ratio equaling 1.0. The O/E ratio for all centers has fallen by 14% over the 4.5-year period of this program (p = 0.06). CONCLUSIONS: A large-scale, low-cost program of continuous quality improvement using risk-adjusted outcome is feasible. This program has been associated with a decrease in risk-adjusted operative mortality. PMID:8147609

Hammermeister, K E; Johnson, R; Marshall, G; Grover, F L

1994-01-01

204

A microchip-based multianalyte assay system for the assessment of cardiac risk.  

PubMed

The development of a novel chip-based multianalyte detection system with a cardiac theme is reported. This work follows the initial reports of "electronic taste chips" whereby multiple solution-phase analytes such as acids, bases, metal cations, and biological cofactors were detected and quantitated. The newly fashioned "cardiac chip" exploits a geometry that allows for isolation and entrapment of single polymeric spheres in micromachined pits while providing to each bead the rapid introduction of a series of reagents/washes through microfluidic structures. The combination of these miniaturized components fosters the completion of complex assays with short analysis times using small sample volumes. Optical signals derived from single beads are used to complete immunological tests that yield outstanding assay characteristics. The power and utility of this new methodology is demonstrated here for the simultaneous detection of the cardiac risk factors, C-reactive protein and interleukin-6, in human serum samples. This demonstration represents the first important step toward the development of a useful cardiac chip that targets numerous risk factors concurrently and one that can be customized readily for specific clinical settings. PMID:12141661

Christodoulides, Nick; Tran, Maiyen; Floriano, Pierre N; Rodriguez, Marc; Goodey, Adrian; Ali, Mehnaaz; Neikirk, Dean; McDevitt, John T

2002-07-01

205

Cardiac Autonomic Regulation under Hypnosis Assessed by Heart Rate Variability: Spectral Analysis and Fractal Complexity  

Microsoft Academic Search

Objective: This study examined the effects of hypnosis on autonomic cardiac control. We hypothesized a modification of autonomic modulation of the heart rate with an enhanced vagal tone during hypnosis compared to baseline. Methods: In 12 healthy subjects (6 men and 6 women, 22.2 ± 1.0 years of age) ECG was recorded at baseline and during hypnosis. Heart rate variability

André E. Aubert; Bart Verheyden; Frank Beckers; Jan Tack; Joris Vandenberghe

2009-01-01

206

Sympathetic restraint of respiratory sinus arrhythmia: implications for vagal-cardiac tone assessment in humans  

NASA Technical Reports Server (NTRS)

Clinicians and experimentalists routinely estimate vagal-cardiac nerve traffic from respiratory sinus arrhythmia. However, evidence suggests that sympathetic mechanisms may also modulate respiratory sinus arrhythmia. Our study examined modulation of respiratory sinus arrhythmia by sympathetic outflow. We measured R-R interval spectral power in 10 volunteers that breathed sequentially at 13 frequencies, from 15 to 3 breaths/min, before and after beta-adrenergic blockade. We fitted changes of respiratory frequency R-R interval spectral power with a damped oscillator model: frequency-dependent oscillations with a resonant frequency, generated by driving forces and modified by damping influences. beta-Adrenergic blockade enhanced respiratory sinus arrhythmia at all frequencies (at some, fourfold). The damped oscillator model fit experimental data well (39 of 40 ramps; r = 0.86 +/- 0.02). beta-Adrenergic blockade increased respiratory sinus arrhythmia by amplifying respiration-related driving forces (P < 0.05), without altering resonant frequency or damping influences. Both spectral power data and the damped oscillator model indicate that cardiac sympathetic outflow markedly reduces heart period oscillations at all frequencies. This challenges the notion that respiratory sinus arrhythmia is mediated simply by vagal-cardiac nerve activity. These results have important implications for clinical and experimental estimation of human vagal cardiac tone.

Taylor, J. A.; Myers, C. W.; Halliwill, J. R.; Seidel, H.; Eckberg, D. L.

2001-01-01

207

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings.  

PubMed

Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 +/- 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 +/- 41.9 ml and 54.9 +/- 29.6 ml, respectively, compared with 132.1 +/- 40.8 ml EDV and 57.6 +/- 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement -46.1/+53.6), while ESV was underestimated by 2.6 ml (-36.6/+31.4). Mean EF was 61.6 +/- 12.4% in DSCT and 57.9 +/- 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at -14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were amounted to 0.85 for EDV, ESV and EF. DSCT offers the possibility to quantify left ventricular function from coronary CT angiography datasets with sufficient diagnostic accuracy, adding to the value of the modality in a comprehensive cardiac assessment. The observed differences in the measured values may be due to different post-processing methods and physiological reactions to contrast material injection without beta-blocker medication. PMID:17909817

Busch, S; Johnson, T R C; Wintersperger, B J; Minaifar, N; Bhargava, A; Rist, C; Reiser, M F; Becker, C; Nikolaou, K

2008-03-01

208

Limitations of Early Serum Creatinine Variations for the Assessment of Kidney Injury in Neonates and Infants with Cardiac Surgery  

PubMed Central

Background Changes in kidney function, as assessed by early and even small variations in serum creatinine (?sCr), affect survival in adults following cardiac surgery but such associations have not been reported in infants. This raises the question of the adequate assessment of kidney function by early ?sCr in infants undergoing cardiac surgery. Methodology The ability of ?sCr within 2 days of surgery to assess the severity of kidney injury, accounted for by the risk of 30-day mortality, was explored retrospectively in 1019 consecutive neonates and infants. Patients aged ? 10 days were analyzed separately because of the physiological improvement in glomerular filtration early after birth. The Kml algorithm, an implementation of k-means for longitudinal data, was used to describe creatinine kinetics, and the receiver operating characteristic and the reclassification methodology to assess discrimination and the predictive ability of the risk of death. Results Three clusters of ?sCr were identified: in 50% of all patients creatinine decreased, in 41.4% it increased slightly, and in 8.6% it rose abruptly. Mortality rates were not significantly different between the first and second clusters, 1.6% [0.0–4.1] vs 5.9% [1.9–10.9], respectively, in patients aged ? 10 days, and 1.6% [0.5–3.0] vs 3.8% [1.9–6.0] in older ones. Mortality rates were significantly higher when creatinine rose abruptly, 30.3% [15.1–46.2] in patients aged ? 10 days, and 15.1% [5.9–25.5] in older ones. However, only 41.3% of all patients who died had an abrupt increase in creatinine. ?sCr improved prediction in survivors, but not in patients who died, and did not improve discrimination over a clinical mortality model. Conclusions The present results suggest that a postoperative decrease in creatinine represents the normal course in neonates and infants with cardiac surgery, and that early creatinine variations lack sensitivity for the assessment of the severity of kidney injury. PMID:24244476

Bojan, Mirela; Lopez-Lopez, Vanessa; Pouard, Philippe; Falissard, Bruno; Journois, Didier

2013-01-01

209

Assessment of cardiac proteome dynamics with heavy water: slower protein synthesis rates in interfibrillar than subsarcolemmal mitochondria.  

PubMed

Traditional proteomics provides static assessment of protein content, but not synthetic rates. Recently, proteome dynamics with heavy water ((2)H2O) was introduced, where (2)H labels amino acids that are incorporated into proteins, and the synthesis rate of individual proteins is calculated using mass isotopomer distribution analysis. We refine this approach with a novel algorithm and rigorous selection criteria that improve the accuracy and precision of the calculation of synthesis rates and use it to measure protein kinetics in spatially distinct cardiac mitochondrial subpopulations. Subsarcolemmal mitochondria (SSM) and interfibrillar mitochondria (IFM) were isolated from adult rats, which were given (2)H2O in the drinking water for up to 60 days. Plasma (2)H2O and myocardial (2)H-enrichment of amino acids were stable throughout the experimental protocol. Multiple tryptic peptides were identified from 28 proteins in both SSM and IFM and showed a time-dependent increase in heavy mass isotopomers that was consistent within a given protein. Mitochondrial protein synthesis was relatively slow (average half-life of 30 days, 2.4% per day). Although the synthesis rates for individual proteins were correlated between IFM and SSM (R(2) = 0.84; P < 0.0001), values in IFM were 15% less than SSM (P < 0.001). In conclusion, administration of (2)H2O results in stable enrichment of the cardiac precursor amino acid pool, with the use of refined analytical and computational methods coupled with cell fractionation one can measure synthesis rates for cardiac proteins in subcellular compartments in vivo, and protein synthesis is slower in mitochondria located among the myofibrils than in the subsarcolemmal region. PMID:23457012

Kasumov, Takhar; Dabkowski, Erinne R; Shekar, Kadambari Chandra; Li, Ling; Ribeiro, Rogerio F; Walsh, Kenneth; Previs, Stephen F; Sadygov, Rovshan G; Willard, Belinda; Stanley, William C

2013-05-01

210

ASSESSING UNCERTAINTIES OF USING DAILY DATA OUTPUTS FROM REGIONAL NUMERICAL CLIMATE MODELS AS INPUTS INTO CROP SIMULATION MODELS  

Microsoft Academic Search

Regional numerical climate models may be able to produce climate forecasts that would provide useful predictions of crop yields several months in advance. In this study, we linked outputs from the Florida State University\\/Center for Ocean-Atmospheric Prediction Studies (FSU\\/COAPS) regional spectral model to a dynamic crop model (CERES-Maize) for evaluating uncertainties in yield prediction for three sites in the southeastern

Guillermo A. Baigorria; James W. Jones; D. W. Shin; Ashok Mishra; James J. O'Brien

211

High-throughput phenotypic assessment of cardiac physiology in four commonly used inbred mouse strains.  

PubMed

Mice with genetic alterations are used in heart research as model systems of human diseases. In the last decade there was a marked increase in the recognition of genetic diversity within inbred mouse strains. Increasing numbers of inbred mouse strains and substrains and analytical variation of cardiac phenotyping methods require reproducible, high-throughput methods to standardize murine cardiovascular physiology. We describe methods for non-invasive, reliable, easy and fast to perform echocardiography and electrocardiography on awake mice. This method can be used for primary screening of the murine cardiovascular system in large-scale analysis. We provide insights into the physiological divergence of C57BL/6N, C57BL/6J, C3HeB/FeJ and 129P2/OlaHsd mouse hearts and define the expected normal values. Our report highlights that compared to the other three strains tested C57BL/6N hearts reveal features of heart failure such as hypertrophy and reduced contractile function. We found several features of the mouse ECG to be under genetic control and obtained several strain-specific differences in cardiac structure and function. PMID:24788387

Moreth, Kristin; Fischer, Ralf; Fuchs, Helmut; Gailus-Durner, Valérie; Wurst, Wolfgang; Katus, Hugo A; Bekeredjian, Raffi; Hrab? de Angelis, Martin

2014-08-01

212

Noninvasive assessment of treatment of cardiac allograft rejection with indium-111-labeled lymphocytes  

SciTech Connect

We have shown previously that cardiac allograft rejection can be detected noninvasively with gamma scintigraphy after administration of indium-111 (111In)-labeled lymphocytes. To determine whether this technique could be used to monitor salvage immunosuppressive therapy in reversing rejection, 5 dogs were studied after thoracic heterotopic cardiac transplantation. Initial postoperative immunosuppression was maintained with cyclosporine (10-20 mg/kg/day) and prednisone (1 mg/kg/day) for 7 days after transplantation and then discontinued. Scintigraphy after administration of labeled lymphocytes was performed during initial immunosuppression and every 3 days after its termination. Endomyocardial biopsies were obtained on each day scintigraphy was performed. Once scintigraphic criteria for rejection were met (111In-lymphocyte uptake greater than mean +/- 2SD of normal myocardium), animals were treated with high dose methylprednisolone and cyclosporine. Myocardial 111In-lymphocyte activity compared with that in blood was 0.7 +/- 0.8 during initial immunosuppression, increased to 5.7 +/- 3.5 after termination of therapy (P less than 0.01), and diminished with salvage immunosuppressive therapy to 0.5 +/- 0.8 (P = NS compared with native hearts or allografts during initial immunosuppression). Scintigraphy accurately predicted all but one episode of biopsy-documented rejection and accurately detected reversal of rejection during salvage. Thus, scintigraphy with 111In-labeled lymphocytes should facilitate noninvasive monitoring of antirejection therapy in patients.

Rosenbloom, M.; Eisen, H.J.; Laschinger, J.; Saffitz, J.E.; Sobel, B.E.; Bergmann, S.R.; Bolman, R.M. III

1988-09-01

213

Cardiac thin filament regulation  

PubMed Central

Myocardial contraction is initiated upon the release of calcium into the cytosol from the sarcoplasmic reticulum following membrane depolarization. The fundamental physiological role of the heart is to pump an amount blood that is determined by the prevailing requirements of the body. The physiological control systems employed to accomplish this task include regulation of heart rate, the amount of calcium release, and the response of the cardiac myofilaments to activator calcium ions. Thin filament activation and relaxation dynamics has emerged as a pivotal regulatory system tuning myofilament function to the beat-to-beat regulation of cardiac output. Maladaptation of thin filament dynamics, in addition to dysfunctional calcium cycling, is now recognized as an important cellular mechanism causing reduced cardiac pump function in a variety of cardiac diseases. Here, we review current knowledge regarding protein–protein interactions involved in the dynamics of thin filament activation and relaxation and the regulation of these processes by protein kinase-mediated phosphorylation. PMID:18421471

Kobayashi, Tomoyoshi; Jin, Lei; de Tombe, Pieter P.

2010-01-01

214

Cardiac lipofibromatosis.  

PubMed

We present a case of cardiac lipofibromatosis associated with atrial fibrillation and complete heart block requiring permanent pacemaker implantation. Multimodality cardiac imaging including transthoracic echocardiography and cardiac magnetic resonance were useful for tissue characterization of this rare cardiac diagnosis. PMID:23146562

Shen, Seeger; Rizkallah, Jacques; Kirkpatrick, Iain D C; Khadem, Ali; Jassal, Davinder S

2013-04-01

215

The Value of Pulmonary Function Studies in the Assessment of Patients for Cardiac Surgery  

PubMed Central

Preoperative pulmonary function, intracardiac pressures and degree of dyspnea were related to the incidence of postoperative respiratory insufficiency in 102 adult patients who underwent cardiac surgery. The purpose was to seek a reliable method of prognosticating the risk of postoperative respiratory insufficiency, especially after the use of cardiopulmonary bypass. When the heart-lung pump was used, 24 of 30 patients with a vital capacity less than 80% of the predicted normal developed respiratory insufficiency, whereas only eight of 41 patients with a normal vital capacity had this complication. In 26 patients where the vital capacity and gas diffusion were both normal, only three developed postoperative respiratory insufficiency. Other single or combined pulmonary function abnormalities, including tests of the mechanics of breathing, were of no greater value in predicting the postoperative course. The degree of dyspnea and the level of intracardiac pressures, although sometimes helpful, were often misleading. PMID:14226102

Ariza-Mendoza, F.; Woolf, C. R.

1964-01-01

216

Evaluation of Hemoglobin A1c Criteria to Assess Preoperative Diabetes Risk in Cardiac Surgery Patients  

PubMed Central

Abstract Objective Hemoglobin A1c (A1C) has recently been recommended for diagnosing diabetes mellitus and diabetes risk (prediabetes). Its performance compared with fasting plasma glucose (FPG) and 2-h post-glucose load (2HPG) is not well delineated. We compared the performance of A1C with that of FPG and 2HPG in preoperative cardiac surgery patients. Methods Data from 92 patients without a history of diabetes were analyzed. Patients were classified with diabetes or prediabetes using established cutoffs for FPG, 2HPG, and A1C. Sensitivity and specificity of the new A1C criteria were evaluated. Results All patients diagnosed with diabetes by A1C also had impaired fasting glucose, impaired glucose tolerance, or diabetes by other criteria. Using FPG as the reference, sensitivity and specificity of A1C for diagnosing diabetes were 50% and 96%, and using 2HPG as the reference they were 25% and 95%. Sensitivity and specificity for identifying prediabetes with FPG as the reference were 51% and 51%, respectively, and with 2HPG were 53% and 51%, respectively. One-third each of patients with prediabetes was identified using FPG, A1C, or both. When testing A1C and FPG concurrently, the sensitivity of diagnosing dysglycemia increased to 93% stipulating one or both tests are abnormal; specificity increased to 100% if both tests were required to be abnormal. Conclusions In patients before cardiac surgery, A1C criteria identified the largest number of patients with diabetes and prediabetes. For diagnosing prediabetes, A1C and FPG were discordant and characterized different groups of patients, therefore altering the distribution of diabetes risk. Simultaneous measurement of FGP and A1C may be a more sensitive and specific tool for identifying high-risk individuals with diabetes and prediabetes. PMID:21854260

Saberi, Sima; Zrull, Christina A.; Patil, Preethi V.; Jha, Leena; Kling-Colson, Susan C.; Gandia, Kenia G.; DuBois, Elizabeth C.; Plunkett, Cynthia D.; Bodnar, Tim W.; Pop-Busui, Rodica

2011-01-01

217

Morphological and Volumetric Analysis of Left Atrial Appendage and Left Atrium: Cardiac Computed Tomography-Based Reproducibility Assessment  

PubMed Central

Objectives Left atrial appendage (LAA) dilatation and morphology may influence an individual's risk for intracardiac thrombi and ischemic stroke. LAA size and morphology can be evaluated using cardiac computed tomography (cCT). The present study evaluated the reproducibility of LAA volume and morphology assessments. Methods A total of 149 patients (47 females; mean age 60.9±10.6 years) with suspected cardioembolic stroke/transient ischemic attack underwent cCT. Image quality was rated based on four categories. Ten patients were selected from each image quality category (N?=?40) for volumetric reproducibility analysis by two individual readers. LAA and left atrium (LA) volume were measured in both two-chamber (2CV) and transversal view (TV) orientation. Intertechnique reproducibility was assessed between 2CV and TV (200 measurement pairs). LAA morphology (A?=?Cactus, B?=?ChickenWing, C?=?WindSock, D?=?CauliFlower), LAA opening height, number of LAA lobes, trabeculation, and orientation of the LAA tip was analysed in all study subjects by three individual readers (447 interobserver measurement pairs). The reproducibility of volume measurements was assessed by intra-class correlation (ICC) and the reproducibility of LAA morphology assessments by Cohen's kappa. Results The intra-observer and interobserver reproducibility of LAA and LA volume measurements was excellent (ICCs>0.9). The LAA (ICC?=?0.954) and LA (ICC?=?0.945) volume measurements were comparable between 2CV and TV. Morphological classification (??=?0.24) and assessments of LAA opening height (??=?0.1), number of LAA lobes (??=?0.16), trabeculation (??=?0.15), and orientation of the LAA tip (??=?0.37) was only slightly to fairly reproducible. Conclusions LA and LAA volume measurements on cCT provide excellent reproducibility, whereas visual assessment of LAA morphological features is challenging and results in unsatisfactory agreement between readers. PMID:24988467

Taina, Mikko; Korhonen, Miika; Haataja, Mika; Muuronen, Antti; Arponen, Otso; Hedman, Marja; Jakala, Pekka; Sipola, Petri; Mustonen, Pirjo; Vanninen, Ritva

2014-01-01

218

Variability in high-throughput ion-channel screening data and consequences for cardiac safety assessment  

PubMed Central

Introduction Unwanted drug interactions with ionic currents in the heart can lead to an increased proarrhythmic risk to patients in the clinic. It is therefore a priority for safety pharmacology teams to detect block of cardiac ion channels, and new technologies have enabled the development of automated and high-throughput screening assays using cell lines. As a result of screening multiple ion-channels there is a need to integrate information, particularly for compounds affecting more than one current, and mathematical electrophysiology in-silico action potential models are beginning to be used for this. Methods We quantified the variability associated with concentration-effect curves fitted to recordings from high-throughput Molecular Devices IonWorks® Quattro™ screens when detecting block of IKr (hERG), INa (NaV1.5), ICaL (CaV1.2), IKs (KCNQ1/minK) and Ito (Kv4.3/KChIP2.2), and the Molecular Devices FLIPR® Tetra fluorescence screen for ICaL (CaV1.2), for control compounds used at AstraZeneca and GlaxoSmithKline. We examined how screening variability propagates through in-silico action potential models for whole cell electrical behaviour, and how confidence intervals on model predictions can be estimated with repeated simulations. Results There are significant levels of variability associated with high-throughput ion channel electrophysiology screens. This variability is of a similar magnitude for different cardiac ion currents and different compounds. Uncertainty in the Hill coefficients of reported concentration-effect curves is particularly high. Depending on a compound’s ion channel blocking profile, the uncertainty introduced into whole-cell predictions can become significant. Discussion Our technique allows confidence intervals to be placed on computational model predictions that are based on high-throughput ion channel screens. This allows us to suggest when repeated screens should be performed to reduce uncertainty in a compound’s action to acceptable levels, to allow a meaningful interpretation of the data. PMID:23651875

Elkins, Ryan C.; Davies, Mark R.; Brough, Stephen J.; Gavaghan, David J.; Cui, Yi; Abi-Gerges, Najah; Mirams, Gary R.

2014-01-01

219

Late cardiac sodium current can be assessed using automated patch-clamp  

PubMed Central

The cardiac late Na + current is generated by a small fraction of voltage-dependent Na + channels that undergo a conformational change to a burst-gating mode, with repeated openings and closures during the action potential (AP) plateau. Its magnitude can be augmented by inactivation-defective mutations, myocardial ischemia, or prolonged exposure to chemical compounds leading to drug-induced (di)-long QT syndrome, and results in an increased susceptibility to cardiac arrhythmias. Using CytoPatch™ 2 automated patch-clamp equipment, we performed whole-cell recordings in HEK293 cells stably expressing human Nav1.5, and measured the late Na + component as average current over the last 100 ms of 300 ms depolarizing pulses to -10 mV from a holding potential of -100 mV, with a repetition frequency of 0.33 Hz. Averaged values in different steady-state experimental conditions were further corrected by the subtraction of current average during the application of tetrodotoxin (TTX) 30 ?M. We show that ranolazine at 10 and 30 ?M in 3 min applications reduced the late Na + current to 75.0 ± 2.7% (mean ± SEM, n = 17) and 58.4 ± 3.5% ( n = 18) of initial levels, respectively, while a 5 min application of veratridine 1 ?M resulted in a reversible current increase to 269.1 ± 16.1% ( n = 28) of initial values. Using fluctuation analysis, we observed that ranolazine 30 ?M decreased mean open probability p from 0.6 to 0.38 without modifying the number of active channels n, while veratridine 1 ?M increased n 2.5-fold without changing p. In human iPSC-derived cardiomyocytes, veratridine 1 ?M reversibly increased APD90 2.12 ± 0.41-fold (mean ± SEM, n = 6). This effect is attributable to inactivation removal in Nav1.5 channels, since significant inhibitory effects on hERG current were detected at higher concentrations in hERG-expressing HEK293 cells, with a 28.9 ± 6.0% inhibition (mean ± SD, n = 10) with 50 ?M veratridine.        PMID:25383189

Gawali, Vaibhavkumar; Todt, Hannes; Knott, Thomas; Scheel, Olaf; Abriel, Hugues

2014-01-01

220

Ischemic injury of the liver in a porcine model of cardiac death assessed by in vivo microdialysis.  

PubMed

This study aims to evaluate the ischemic injury of the liver in a porcine model of cardiac death assessed by in vivo microdialysis. A porcine model of cardiac death was established by the suffocation method. Metabolic indicators were monitored using the microdialysis technique during warm ischemia time (WIT) and cold ischemia time (CIT). Pathological changes in ischemic-injured livers were observed by haematoxylin-eosin staining. The predictive values of biochemical parameters regarding the liver donor were evaluated by receiver operating characteristic curve analysis. All statistical analyses were conducted using the SPSS 18.0 software (SPSS Inc, Chicago, Illinois, USA). The degree of warm ischemic injury of the livers increased with prolonged WIT. Serum glucose, glycerol, pyruvate, lactic acid levels and lactate-to-pyruvate (L/P) ratio increased gradually during WIT. Results from Pearson correlation analyses indicated that serum lactate level and L/P ratio were positively associated with the degree of warm ischemic injury of the livers. The degree of cold ischemic injury of the livers gradually increased after 12 h CIT. Serum glucose, lactic acid and L/P ratio achieved a peak after 6-8 h of CIT, but gradually decreased with prolonged CIT. The peak of glycerol occurred after 8 h of CIT, while no changes were found with prolonged CIT. Serum pyruvate level exhibited an increasing trend after 12 h CIT. Our results confirmed that serum glucose and lactate levels were negatively correlated with cold ischemic injury of the liver. However, serum glycerol and pyruvate levels showed positive correlations with cold ischemic injury of the liver. The liver donor was unavailable after 30 min WIT and 24 h CIT. The cut-off value of serum lactate level for warm ischemic injury of the livers was 2.374 with a sensitivity (Sen) of 90 % and specificity (Spe) of 95 %; while the L/P radio was 0.026 (Sen = 80 %, Spe = 83 %). In addition, the cut-off values of serum glucose, lactate, glycerol and pyruvate levels for cold ischemic injury of the livers were 0.339 (Sen = 100 %, Spe = 77 %), 1.172 (Sen = 100 %, Spe = 61 %), 56.359 (Sen = 100 %, Spe = 65 %) and 0.020 (Sen = 100 %, Spe = 67 %), respectively. Our findings provide empirical evidences that serum glucose, lactate levels and L/P ratio may be good indicators for the degree of warm ischemic injury of the livers after cardiac death; while serum glucose, lactate, glycerol and pyruvate levels may be important in predicting cold ischemic injury. PMID:25167853

Yi, De-Hui; Liu, Hao; Chen, Ying; Li, Hong; Xu, Tie; Liu, Yong-Feng

2014-10-01

221

Atherosclerosis and cardiac function assessment in low-density lipoprotein receptor-deficient mice undergoing body weight cycling  

PubMed Central

Background: Obesity has become an epidemic in many countries and is supporting a billion dollar industry involved in promoting weight loss through diet, exercise and surgical procedures. Because of difficulties in maintaining body weight reduction, a pattern of weight cycling often occurs (so called ‘yo-yo' dieting) that may result in deleterious outcomes to health. There is controversy about cardiovascular benefits of yo-yo dieting, and an animal model is needed to better understand the contributions of major diet and body weight changes on heart and vascular functions. Our purpose is to determine the effects of weight cycling on cardiac function and atherosclerosis development in a mouse model. Methods: We used low-density lipoprotein receptor-deficient mice due to their sensitivity to metabolic syndrome and cardiovascular diseases when fed high-fat diets. Alternating ad libitum feeding of high-fat and low-fat (rodent chow) diets was used to instigate weight cycling during a 29-week period. Glucose tolerance and insulin sensitivity tests were done at 22 and 24 weeks, echocardiograms at 25 weeks and atherosclerosis and plasma lipoproteins assessed at 29 weeks. Results: Mice subjected to weight cycling showed improvements in glucose homeostasis during the weight loss cycle. Weight-cycled mice showed a reduction in the severity of atherosclerosis as compared with high-fat diet-fed mice. However, atherosclerosis still persisted in weight-cycled mice as compared with mice fed rodent chow. Cardiac function was impaired in weight-cycled mice and matched with that of mice fed only the high-fat diet. Conclusion: This model provides an initial structure in which to begin detailed studies of diet, calorie restriction and surgical modifications on energy balance and metabolic diseases. This model also shows differential effects of yo-yo dieting on metabolic syndrome and cardiovascular diseases. PMID:23797386

McMillen, T S; Minami, E; LeBoeuf, R C

2013-01-01

222

Thoracic aorta cardiac-cycle related dynamic changes assessed with a 256-slice CT scanner  

PubMed Central

Objective The aim of our study was to demonstrate whether the dynamic changes previously documented at the ascending and abdominal aorta are replicated at the thoracic aorta. Methods and results A consecutive series of thirty patients referred to our institution to undergo CT angiography of the thoracic aorta (CTA) constituted the study population. Patients with diffuse aortic atherosclerosis were excluded from the analysis. All studies were acquired with a 256-MDCT scanner and ECG-gating was performed in all cases. Two orthogonal imaging planes (maximal and minimal diameters) were obtained at three different levels of the descending thoracic aorta, using the distance from the left subclavian artery as proximal landmark: 10, 40, and 80 mm distance. The mean age was 58.9±15.7 years and 16 (53%) patients were male. Descending aorta measurements at 10, 40, and 80 mm distance from the left subclavian artery were all significantly larger within the systolic window (P<0.01 for all comparisons). Measurements of the maximal diameter were systematically larger than the minimal diameters among all aortic positions including ungated, systolic, and diastolic measurements (P<0.05 for all comparisons). Conclusions The main finding of our pilot investigation was that the thoracic descending aorta undergoes significant conformational changes during the cardiac cycle, irrespective from the distance from the left subclavian artery. PMID:24282760

Carrascosa, Patricia; Capunay, Carlos; Deviggiano, Alejandro; Rodriguez-Granillo, Gaston A.; Sagarduy, Maria Ines; Cortines, Patricio; Carrascosa, Jorge; Parodi, Juan C.

2013-01-01

223

Application of Lidar Data in the Assessment of Observed and Model Output Temperature Soundings During the Pacific 2001 Field Study.  

NASA Astrophysics Data System (ADS)

Surface and airborne lidar, along with upper air soundings and model derived soundings were examined over the course of the Pacific 2001 Air Quality Field Study. The general region of interest in this report is the Georgia Basin with a focus on the Lower Fraser Valley of British Columbia. Data included the following: RASCAL (Rapid Acquisition SCanning Aerosol Lidar), a surface-based scanning lidar facility at the Langley Lochiel site, operating close to 16 hours each day; AERIAL (AERosol Imaging Airborne Lidar), a simultaneous upward/downward airborne lidar system providing 9 flights during the field study; radiosondes, released 4 times daily from the Langley Poppy site; and once-daily 3.3 km resolution MC2 (Mesoscale Compressible Community weather prediction) model output. Methods of diagnosing mixing heights amongst the various datasets are outlined. The higher resolution lidar data provides a means of calibrating mixing heights from radiosondes and also allows a means of evaluating model derived soundings. Results show that in most cases there is good agreement amongst the various sources of data. This data is then used to demonstrate the variation of mixing height with sea breeze activity over the Lower Fraser Valley.

Strawbridge, K. B.; Snyder, B. J.

2002-12-01

224

ASSESSMENT OF MATHEMATICAL MODELS FOR STORM AND COMBINED SEWER MANAGEMENT. APPENDIX F: SELECTED COMPUTER INPUT AND OUTPUT  

EPA Science Inventory

Mathematical models for the nonsteady simulation of urban runoff were evaluated to determine their suitability for the engineering assessment, planning, design and control of storm and combined sewerage systems. The models were evaluated on the basis of information published by t...

225

Assessment of cardiovascular volume status by transoesophageal echocardiography and dye dilution during cardiac surgery.  

PubMed

Conventional evaluation of cardiovascular volume status by filling pressures is unreliable in critically ill patients. Measurements of left ventricular end diastolic area index by transoesophageal echocardiography and of intrathoracic blood volume index by dye indicator dilution are new approaches to this problem. In this study, different indices of cardiovascular volume status were analysed to define their relation during the pronounced haemodynamic changes associated with systemic inflammation after cardiopulmonary bypass. Correlations were performed with left ventricular end diastolic area index, intrathoracic blood volume index, central venous pressure (CVP) and pulmonary capillary wedge pressure (PCWP). Data from 15 patients receiving coronary artery bypass grafts were compared after induction of anaesthesia and in the intensive care unit. Spearman's correlation coefficient for perioperative absolute changes in left ventricular end diastolic area index and intrathoracic blood volume index was 0.87 (P < 0.05). However, an increase in intrathoracic blood volume index by 125 mL m-2 was necessary to maintain a baseline left ventricular end diastolic area index. Absolute values of all variables varied widely, with the only significant correlation found between CVP and PCWP. Changes in CVP and PCWP did not correlate with changes in left ventricular end diastolic area index or intrathoracic blood volume index. Provided simultaneous baseline measurements are available and a supranormal intrathoracic blood volume index compensates for the haemodynamic changes in systemic inflammation, left ventricular end diastolic area index and intrathoracic blood volume index may substitute for each other during the evaluation of cardiovascular volume status in patients with stable cardiac function. PMID:9884847

Hinder, F; Poelaert, J I; Schmidt, C; Hoeft, A; Möllhoff, T; Loick, H M; Van Aken, H

1998-11-01

226

Apparent racial disparity in the utilization of invasive testing for risk assessment of cardiac patients undergoing noncardiac surgery  

Microsoft Academic Search

BackgroundStudies on racial disparity in the use of cardiac diagnostic procedures are limited because they were conducted in the acute clinical setting without control for patient knowledge and emotional state or used models not controlling for racism. Using the setting (model) of elective evaluation of known, stable, cardiac patients undergoing noncardiac surgery, where the surgeon\\/anesthesiologist's personal interest precludes expression of

Constantine A. Hassapoyannes; Dan-Victor Giurgiutiu; Gregory Eaves; Mohammad-Reza Movahed

2006-01-01

227

Undersampled Cine 3D tagging for rapid assessment of cardiac motion  

PubMed Central

Background CMR allows investigating cardiac contraction, rotation and torsion non-invasively by the use of tagging sequences. Three-dimensional tagging has been proposed to cover the whole-heart but data acquisition requires three consecutive breath holds and hence demands considerable patient cooperation. In this study we have implemented and studied k-t undersampled cine 3D tagging in conjunction with k-t PCA reconstruction to potentially permit for single breath-hold acquisitions. Methods The performance of undersampled cine 3D tagging was investigated using computer simulations and in-vivo measurements in 8 healthy subjects and 5 patients with myocardial infarction. Fully sampled data was obtained and compared to retrospectively and prospectively undersampled acquisitions. Fully sampled data was acquired in three consecutive breath holds. Prospectively undersampled data was obtained within a single breath hold. Based on harmonic phase (HARP) analysis, circumferential shortening, rotation and torsion were compared between fully sampled and undersampled data using Bland-Altman and linear regression analysis. Results In computer simulations, the error for circumferential shortening was 2.8?±?2.3% and 2.7?±?2.1% for undersampling rates of R?=?3 and 4 respectively. Errors in ventricular rotation were 2.5?±?1.9% and 3.0?±?2.2% for R?=?3 and 4. Comparison of results from fully sampled in-vivo data acquired with prospectively undersampled acquisitions showed a mean difference in circumferential shortening of ?0.14?±?5.18% and 0.71?±?6.16% for R?=?3 and 4. The mean differences in rotation were 0.44?±?1.8° and 0.73?±?1.67° for R?=?3 and 4, respectively. In patients peak, circumferential shortening was significantly reduced (p?

2012-01-01

228

Maternal hyperglycemia leads to fetal cardiac hyperplasia and dysfunction in a rat model.  

PubMed

Accelerated fetal myocardial growth with altered cardiac function is a well-documented complication of human diabetic pregnancy, but its pathophysiology is still largely unknown. Our aim was to explore the mechanisms of fetal cardiac remodeling and cardiovascular hemodynamics in a rat model of maternal pregestational streptozotocin-induced hyperglycemia. The hyperglycemic group comprised 107 fetuses (10 dams) and the control group 219 fetuses (20 dams). Fetal cardiac function was assessed serially by Doppler ultrasonography. Fetal cardiac to thoracic area ratio, newborn heart weight, myocardial cell proliferative and apoptotic activities, and cardiac gene expression patterns were determined. Maternal hyperglycemia was associated with increased cardiac size, proliferative, apoptotic and mitotic activities, upregulation of genes encoding A- and B-type natriuretic peptides, myosin heavy chain types 2 and 3, uncoupling proteins 2 and 3, and the angiogenetic tumor necrosis factor receptor superfamily member 12A. The genes encoding Kv channel-interacting protein 2, a regulator of electrical cardiac phenotype, and the insulin-regulated glucose transporter 4 were downregulated. The heart rate was lower in fetuses of hyperglycemic dams. At 13-14 gestational days, 98% of fetuses of hyperglycemic dams had holosystolic atrioventricular valve regurgitation and decreased outflow mean velocity, indicating diminished cardiac output. Maternal hyperglycemia may lead to accelerated fetal myocardial growth by cardiomyocyte hyperplasia. In fetuses of hyperglycemic dams, expression of key genes that control and regulate cardiomyocyte electrophysiological properties, contractility, and metabolism are altered and may lead to major functional and clinical implications on the fetal heart. PMID:23839525

Lehtoranta, Lara; Vuolteenaho, Olli; Laine, V Jukka; Koskinen, Anna; Soukka, Hanna; Kytö, Ville; Määttä, Jorma; Haapsamo, Mervi; Ekholm, Eeva; Räsänen, Juha

2013-09-01

229

Introduction--databases and the assessment of complications associated with the treatment of patients with congenital cardiac disease.  

PubMed

The Multi-Societal Database Committee for Pediatric and Congenital Heart Disease was established in 2005 with the goal of providing the infrastructure, spanning geographical and subspecialty boundaries, for collaboration between health care professionals interested in the analysis of outcomes of treatments provided to patients with congenital cardiac disease, with the ultimate aim of improvement in the quality of care provided to these patients. The purpose of these collaborative efforts is to promote the highest quality comprehensive cardiac care to all patients with congenital heart disease, from the fetus to the adult, regardless of the patient's economic means, with an emphasis on excellence in teaching, research and community service. This manuscript provides the Introduction to the 2008 Supplement to Cardiology in the Young titled: "Databases and The Assessment of Complications associated with the Treatment of Patients with Congenital Cardiac Disease". This Supplement was prepared by The Multi-Societal Database Committee for Pediatric and Congenital Heart Disease. The Multi-Societal Database Committee for Pediatric and Congenital Heart Disease offers the following definition of the term "Complication": "A complication is an event or occurrence that is associated with a disease or a healthcare intervention, is a departure from the desired course of events, and may cause, or be associated with, suboptimal outcome. A complication does not necessarily represent a breech in the standard of care that constitutes medical negligence or medical malpractice. An operative or procedural complication is any complication, regardless of cause, occurring (1) within 30 days after surgery or intervention in or out of the hospital, or (2) after 30 days during the same hospitalization subsequent to the operation or intervention. Operative and procedural complications include both intraoperative/intraprocedural complications and postoperative/postprocedural complications in this time interval." The Multi-Societal Database Committee for Pediatric and Congenital Heart Disease offers the following definition of the term "Adverse Event": "An adverse event is a complication that is associated with a healthcare intervention and is associated with suboptimal outcome. Adverse events represent a subset of complications. Not all medical errors result in an adverse event; the administration of an incorrect dose of a medication is a medical error, but it does not always result in an adverse event. Similarly, not all adverse events are the result of medical error. A child may develop pneumonia after an atrial septal defect repair despite intra- and peri-operative management that is free of error. Complications of the underlying disease state, which are not related to a medical intervention, are not adverse events. For example, a patient who presents for medical care with metastatic lung cancer has already developed a complication (Metastatic spread) of the primary lung cancer without any healthcare intervention. Furthermore, complications not associated with suboptimal outcome or harm are not adverse events and are known as no harm events. The patient who receives an incorrect dose of a medication without harm has experienced a no harm event, but not an adverse event." Based on the above definitions, it is apparent that The Multi-Societal Database Committee for Pediatric and Congenital Heart Disease has taken an inclusive approach to defining the universe of complications. Complications may or may not be associated with healthcare intervention and may or may not be associated with suboptimal outcome. Meanwhile, adverse events must be associated with healthcare intervention and must be associated with suboptimal outcome. PMID:19063774

Jacobs, Jeffrey P

2008-12-01

230

Dynamic cardiac mapping on patient-specific cardiac models.  

PubMed

Minimally invasive techniques for electrophysiological cardiac data mapping and catheter ablation therapy have been driven through advancements in computer-aided technologies, including magnetic tracking systems, and virtual and augmented-reality environments. The objective of this work is to extend current cardiac mapping techniques to collect and display data in the temporal domain, while mapping on patient-specific cardiac models. This paper details novel approaches to collecting spatially tracked cardiac electrograms, registering the data with a patient-specific cardiac model, and interpreting the data directly on the model surface, with the goal of giving a more comprehensive cardiac mapping system in comparison to current systems. To validate the system, laboratory studies were conducted to assess the accuracy of navigating to both physical and virtual landmarks. Subsequent to the laboratory studies, an in-vivo porcine experiment was conducted to assess the systems overall ability to collect spatial tracked electrophysiological data, and map directly onto a cardiac model. The results from these experiments show the new dynamic cardiac mapping system was able to maintain high accuracy of locating physical and virtual landmarks, while creating a dynamic cardiac map displayed on a dynamic cardiac surface model. PMID:18979839

Wilson, Kevin; Guiraudon, Gerard; Jones, Doug; Linte, Cristian A; Wedlake, Chris; Moore, John; Peters, Terry M

2008-01-01

231

Renal function assessment in child and adolescent heart transplant recipients during routine cardiac catheterization.  

PubMed

CKD identification after pediatric heart transplantation (PHT) is limited by inaccuracies in estimates of GFR. We hypothesized that GFR can be measured by a modified iohexol clearance protocol in PHT recipients and that the CKiD formula provides a better estimate of GFR than other estimating equations. A cross-sectional study of PHT recipients, ages 2-18 yr, undergoing coronary angiography was undertaken. The angiography dose of iohexol was divided by the area under the curve from three iohexol levels post-infusion to calculate GFR. Agreement between iGFR and multiple estimating equations (eGFR) was assessed. In 31 subjects, median age was 15.0 yr (IQR 7.6, 16.6). Mean iGFR was 93.8 (s.d. 22.5) mL/min/1.73 m(2) ; 16 (52%) had an iGFR <90 mL/min/1.73 m(2) . The full CKiD formula (mean eGFR 88.9, s.d. 14.9) had low bias (-5.0), narrowest 95% limits of agreement (-42.0, 32.1), highest 30% (94%) and 10% (52%) accuracy, and highest correlation coefficient (0.576) relative to iGFR. We describe a novel modified iohexol clearance method to assess GFR after PHT. Over half of the cohort had an iGFR <90, suggesting CKD. The full CKiD formula performs best with respect to bias, accuracy, and correlation. PMID:25112413

Lin, Kimberly Y; Furth, Susan L; Schwartz, George J; Shaddy, Robert E; Ruebner, Rebecca L

2014-11-01

232

Assessment of cardiac contractility during a cold pressor test by using (d P \\/d t )\\/ P of carotid artery pulses  

Microsoft Academic Search

The ratio of the first derivative (dP\\/dt) of a carotid artery pulse to the developed pressure (P), (dP\\/dt)\\/P, is an easily measurable, noninvasive index of cardiac contractility even in moderate exercise. We examined the effects of\\u000a transient cold exposure on cardiac contractility in normal reactors (n = 12) and hyperreactors (an increase in systolic or diastolic pressure >15 mm Hg; n = 6) by using this

Kayo Moriyama; Hirotoshi Ifuku

2007-01-01

233

Cardiac image segmentation for contrast agent videodensitometry  

Microsoft Academic Search

Indicator dilution techniques are widely used in the intensive care unit and operating room for cardiac parameter measurements. However, the invasiveness of current techniques represents a limitation for their clinical use. The development of stable ultrasound contrast agents allows new applications of the indicator dilution method. Ultrasound contrast agent dilutions permit an echographic noninvasive measurement of cardiac output, ejection fraction,

Massimo Mischi; Antonius A. C. M. Kalker; Henricus H. M. Korsten

2005-01-01

234

Update on intravenous dipyridamole cardiac imaging in the assessment of ischemic heart disease  

SciTech Connect

Intravenous dipyridamole is a relative selective coronary vasodilator which, when combined with thallium-201, provides a useful technique to assess myocardial perfusion. The intravenous dipyridamole is administered as an infusion at a rate of 0.14 mg/kg/min for 4 minutes. In the presence of significant coronary artery disease the increase of coronary blood flow is disproportionate between vessels with and without significant coronary lesions, providing the basis for detecting regional differences in flow using thallium-201. The test can be used alone or combined with low level exercise to increase test sensitivity. The test is safe when performed under medical supervision and when patient selection is done appropriately. Most of the side effects induced by dipyridamole infusion are well tolerated by patients and readily reversed with intravenous aminophylline and sublingual nitroglycerin. The average sensitivity and specificity of the dipyridamole thallium scintigraphy test from the major studies are 76% and 70%, respectively. The test is very useful in providing prognostic information in patients who are unable to exercise. A reversible thallium defect after dipyridamole infusion has been shown to be associated with significant mortality and morbidity in patients with documented or suspected coronary artery disease. The use of intravenous dipyridamole has been extended into other modalities of imaging, including 2-dimensional and Doppler echocardiography, to study functional changes in the left ventricular induced by the infusion of intravenous dipyridamole. 52 references.

Younis, L.T.; Chaitman, B.R. (St. Louis Univ. School of Medicine, MO (USA))

1990-01-01

235

Radiation dose assessment in a 320-detector-row CT scanner used in cardiac imaging  

SciTech Connect

Purpose: In the present era of cone-beam CT scanners, the use of the standardized CTDI{sub 100} as a surrogate of the idealized CTDI is strongly discouraged and, consequently, so should be the use of the dose-length product (DLP) as an estimate of the total energy imparted to the patient. However, the DLP is still widely used as a reference quantity to normalize the effective dose for a given scan protocol mainly because the CTDI{sub 100} is an easy-to-measure quantity. The aim of this article is therefore to describe a method for radiation dose assessment in large cone-beam single axial scans, which leads to a straightforward estimation of the total energy imparted to the patient. The authors developed a method accessible to all medical physicists and easy to implement in clinical practice in an attempt to update the bridge between CT dosimetry and the estimation of the effective dose. Methods: The authors used commercially available material and a simple mathematical model. The method described herein is based on the dosimetry paradigm introduced by the AAPM Task Group 111. It consists of measuring the dose profiles at the center and the periphery of a long body phantom with a commercial solid-state detector. A weighted dose profile is then calculated from these measurements. To calculate the CT dosimetric quantities analytically, a Gaussian function was fitted to the dose profile data. Furthermore, the Gaussian model has the power to condense the z-axis information of the dose profile in two parameters: The single-scan central dose, f(0), and the width of the profile, {sigma}. To check the energy dependence of the solid-state detector, the authors compared the dose profiles to measurements made with a small volume ion chamber. To validate the overall method, the authors compared the CTDI{sub 100} calculated analytically to the measurement made with a 100 mm pencil ion chamber. Results: For the central and weighted dose profiles, the authors found a good agreement between the measured dose profile data and the fitted Gaussian functions. The solid-state detector had no energy dependence--within the energy range of interest--and the analytical model succeeded in reproducing the absolute dose values obtained with the pencil ion chamber. For the case of large cone-beam single axial scans, the quantity that better characterizes the total energy imparted to the patient is the weighted dose profile integral (DPI{sub w}). The DPI{sub w} can be easily determined from the two parameters that define the Gaussian functions: f(0) and {sigma}. The authors found that the DLP underestimated the total energy imparted to the patient by more than 20%. The authors also found that the calculated CT dosimetric quantities were higher than those displayed on the scanner console. Conclusions: The authors described and validated a method to assess radiation dose in large cone-beam single axial scans. This method offers a simple and more accurate estimation of the total energy imparted to the patient, thus offering the possibility to update the bridge between CT dosimetry and the estimation of the effective dose for cone-beam CT examinations in radiology, nuclear medicine, and radiation therapy.

Goma, Carles; Ruiz, Agustin; Jornet, Nuria; Latorre, Artur; Pallerol, Rosa M.; Carrasco, Pablo; Eudaldo, Teresa; Ribas, Montserrat [Servei de Radiofisica i Radioproteccio, Hospital de la Santa Creu i Sant Pau, Sant Antoni Maria Claret 167, 08025 Barcelona (Spain)

2011-03-15

236

A Novel Methodology for Assessing the Bounded-Input Bounded-Output Instability in QT Interval Dynamics: Application to Clinical ECG With Ventricular Tachycardia  

PubMed Central

The goal of this paper is to present a new methodology for assessing the bounded-input bounded-output (BIBO) stability in QT interval (QTI) dynamics from clinical ECG. The ECG recordings were collected from 15 patients who experienced ventricular tachycardia (VT). Ten-minute-long ECG recordings extracted immediately before the onset of a chosen VT, one per patient, were assembled into a VT group, while the control group comprised 10-min-long ECGs extracted 1 h before VT onset and at least 1 h after any prior arrhythmic event. Each 10-min recording was subdivided into 1-min ECG recordings (minECGs). The QTI dynamics of each minECG was defined as a function of several prior QTIs and RR intervals; the BIBO stability of this function was then assessed in the z-domain. The number of minECGs with unstable QTI dynamics (Nus) and the frequency of premature activations (PA), fPA, were counted for each ECG recording and were compared between the VT and control groups. The results show that the present methodology successfully captured the instability in QTI dynamics leading to VT onset in the studied population. Significantly larger Nus was found in the VT group compared against the control and a positive correlation between Nus and fPA was identified in both groups. PMID:21984490

Chen, Xiaozhong; Trayanova, Natalia A.

2012-01-01

237

Exceptional CO? tolerance in white sturgeon (Acipenser transmontanus) is associated with protection of maximum cardiac performance during hypercapnia in situ.  

PubMed

White sturgeon rank among the most CO?-tolerant fish species examined to date. We investigated whether this exceptional CO? tolerance extended to the heart, an organ generally viewed as acidosis intolerant. Maximum cardiac output (Q(max)) and maximum cardiac power output (PO(max)) were assessed using a working, perfused, in situ heart preparation. Exposure to a Pco? of 3 kPa for 20 min had no significant effect on maximum cardiac performance, while exposure to 6-kPa Pco? reduced heart rate, Q(max), PO(max), and rate of ventricular force generation (F(O)) by 23%, 28%, 26%, and 18%, respectively; however, full recovery was observed in all these parameters upon return to control conditions. These modest impairments during exposure to 6-kPa Pco? were associated with partially compensated intracellular ventricular acidosis. Maximum adrenergic stimulation (500 nmol L?¹ adrenaline) during 6-kPa Pco? protected maximum cardiac performance via increased inotropy (force of contraction) without affecting heart rate. Exposure to higher CO? levels associated with morbidity in vivo (i.e., 8-kPa Pco?) induced arrhythmia and a reduction in stroke volume during power assessment. Clearly, white sturgeon hearts are able to increase cardiac performance during severe hypercapnia that is lethal to other fishes. Future work focusing on atypical aspects of sturgeon cardiac function, including the lack of chronotropic response to adrenergic stimulation during hypercapnia, is warranted. PMID:21527814

Baker, Daniel W; Hanson, Linda M; Farrell, Anthony P; Brauner, Colin J

2011-01-01

238

Assessment of phase based dose modulation for improved dose efficiency in cardiac CT on an anthropomorphic motion phantom  

NASA Astrophysics Data System (ADS)

State of the art automatic exposure control modulates the tube current across view angle and Z based on patient anatomy for use in axial full scan reconstructions. Cardiac CT, however, uses a fundamentally different image reconstruction that applies a temporal weighting to reduce motion artifacts. This paper describes a phase based mA modulation that goes beyond axial and ECG modulation; it uses knowledge of the temporal view weighting applied within the reconstruction algorithm to improve dose efficiency in cardiac CT scanning. Using physical phantoms and synthetic noise emulation, we measure how knowledge of sinogram temporal weighting and the prescribed cardiac phase can be used to improve dose efficiency. First, we validated that a synthetic CT noise emulation method produced realistic image noise. Next, we used the CT noise emulation method to simulate mA modulation on scans of a physical anthropomorphic phantom where a motion profile corresponding to a heart rate of 60 beats per minute was used. The CT noise emulation method matched noise to lower dose scans across the image within 1.5% relative error. Using this noise emulation method to simulate modulating the mA while keeping the total dose constant, the image variance was reduced by an average of 11.9% on a scan with 50 msec padding, demonstrating improved dose efficiency. Radiation dose reduction in cardiac CT can be achieved while maintaining the same level of image noise through phase based dose modulation that incorporates knowledge of the cardiac reconstruction algorithm.

Budde, Adam; Nilsen, Roy; Nett, Brian

2014-03-01

239

Cardiac metastases  

Microsoft Academic Search

Tumours metastatic to the heart (cardiac metastases) are among the least known and highly debated issues in oncology, and few systematic studies are devoted to this topic. Although primary cardiac tumours are extremely uncommon (various postmortem studies report rates between 0.001% and 0.28%), secondary tumours are not, and at least in theory, the heart can be metastasised by any malignant

R Bussani; F De-Giorgio; A Abbate; F Silvestri

2007-01-01

240

Cardiac asthma.  

PubMed

Cardiac dyspnea, especially if present only with exercise, is often confused with asthma and exercise-induced bronchospasm. Cardiac dyspnea or asthma is the consequence of pulmonary edema due to pulmonary venous hypertension and not due to asthmatic bronchoconstriction. In overt, acute congestive heart failure, the diagnosis may be readily made by history and physical examination and pertinent laboratory and imaging data. PMID:23337063

Buckner, Kern

2013-02-01

241

Necessity of angiotensin-converting enzyme-related gene for cardiac functions and longevity of Drosophila melanogaster assessed by optical coherence tomography  

NASA Astrophysics Data System (ADS)

Prior studies have established the necessity of an angiotensin-converting enzyme-related (ACER) gene for heart morphogenesis of Drosophila. Nevertheless, the physiology of ACER has yet to be comprehensively understood. Herein, we employed RNA interference to down-regulate the expression of ACER in Drosophila's heart and swept source optical coherence tomography to assess whether ACER is required for cardiac functions in living adult flies. Several contractile parameters of Drosophila heart, including the heart rate (HR), end-diastolic diameter (EDD), end-systolic diameter (ESD), percent fractional shortening (%FS), and stress-induced cardiac performance, are shown, which are age dependent. These age-dependent cardiac functions declined significantly when ACER was down-regulated. Moreover, the lifespans of ACER knock-down flies were significantly shorter than those of wild-type control flies. Thus, we posit that ACER, the Drosophila ortholog of mammalian angiotensin-converting enzyme 2 (ACE2), is essential for both heart physiology and longevity of animals. Since mammalian ACE2 controls many cardiovascular physiological features and is implicated in cardiomyopathies, our findings that ACER plays conserved roles in genetically tractable animals will pave the way for uncovering the genetic pathway that controls the renin-angiotensin system.

Liao, Fang-Tsu; Chang, Cheng-Yi; Su, Ming-Tsan; Kuo, Wen-Chuan

2014-01-01

242

Comparisons of four categories of waste recycling in China's paper industry based on physical input-output life-cycle assessment model  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Using crop straws and wood wastes for paper production should be promoted. Black-Right-Pointing-Pointer Bagasse and textile waste recycling should be properly limited. Black-Right-Pointing-Pointer Imports of scrap paper should be encouraged. Black-Right-Pointing-Pointer Sensitivity analysis, uncertainties and policy implications are discussed. - Abstract: Waste recycling for paper production is an important component of waste management. This study constructs a physical input-output life-cycle assessment (PIO-LCA) model. The PIO-LCA model is used to investigate environmental impacts of four categories of waste recycling in China's paper industry: crop straws, bagasse, textile wastes and scrap paper. Crop straw recycling and wood utilization for paper production have small total intensity of environmental impacts. Moreover, environmental impacts reduction of crop straw recycling and wood utilization benefits the most from technology development. Thus, using crop straws and wood (including wood wastes) for paper production should be promoted. Technology development has small effects on environmental impacts reduction of bagasse recycling, textile waste recycling and scrap paper recycling. In addition, bagasse recycling and textile waste recycling have big total intensity of environmental impacts. Thus, the development of bagasse recycling and textile waste recycling should be properly limited. Other pathways for reusing bagasse and textile wastes should be explored and evaluated. Moreover, imports of scrap paper should be encouraged to reduce large indirect impacts of scrap paper recycling on domestic environment.

Liang Sai [School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084 (China); Zhang, Tianzhu, E-mail: zhangtz@mail.tsinghua.edu.cn [School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084 (China); Xu Yijian [School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084 (China); China Academy of Urban Planning and Design, Beijing 100037 (China)

2012-03-15

243

Databases for assessing the outcomes of the treatment of patients with congenital and paediatric cardiac disease--the perspective of cardiology.  

PubMed

This review includes a brief discussion, from the perspective of the pediatric cardiologist, of the rationale for creation and maintenance of multi-institutional databases of outcomes of the treatment of patients with congenital and paediatric cardiac disease, together with a history of the evolution of such databases, and a description of the current state of the art. A number of projects designed to have broad-based impact are currently in the design phase, or have already been implemented. Not surprisingly, most of the efforts thus far have focused on catheterization procedures and interventions, although some work examining other aspects of paediatric cardiology practice is also beginning. This review briefly describes several European and North American initiatives related to databases for pediatric and congenital cardiology including the Central Cardiac Audit Database of the United Kingdom, national database initiatives for pediatric cardiology in Switzerland and Germany, various database initiatives under the leadership of the Working Groups of The Association for European Paediatric Cardiology, the IMPACT Registry (IMproving Pediatric and Adult Congenital Treatment) of the National Cardiovascular Data Registry of The American College of Cardiology Foundation and The Society for Cardiovascular Angiography and Interventions (SCAI), the Mid-Atlantic Group of Interventional Cardiology (MAGIC) Catheterization Outcomes Project, the Congenital Cardiac Catheterization Project on Outcomes (C3PO), the Congenital Cardiovascular Interventional Study Consortium (CCISC), and the Joint Council on Congenital Heart Disease (JCCHD) National Quality Improvement Initiative. These projects, each leveraging multicentre data and collaboration, demonstrate the enormous progress that has occurred over the last several years to improve the quality and consistency of information about nonsurgical treatment for congenital cardiac disease. The paediatric cardiology field is well-poised to move quickly beyond outcome assessment and benchmarking, to collaborative quality improvement. PMID:19063781

Jenkins, Kathy J; Beekman Iii, Robert H; Bergersen, Lisa J; Everett, Allen D; Forbes, Thomas J; Franklin, Rodney C G; Klitzner, Thomas S; Krogman, Otto N; Martin, Gerard R; Webb, Catherine L

2008-12-01

244

A dual propagation contours technique for semi-automated assessment of systolic and diastolic cardiac function by CMR  

PubMed Central

Background Although cardiovascular magnetic resonance (CMR) is frequently performed to measure accurate LV volumes and ejection fractions, LV volume-time curves (VTC) derived ejection and filling rates are not routinely calculated due to lack of robust LV segmentation techniques. VTC derived peak filling rates can be used to accurately assess LV diastolic function, an important clinical parameter. We developed a novel geometry-independent dual-contour propagation technique, making use of LV endocardial contours manually drawn at end systole and end diastole, to compute VTC and measured LV ejection and filling rates in hypertensive patients and normal volunteers. Methods 39 normal volunteers and 49 hypertensive patients underwent CMR. LV contours were manually drawn on all time frames in 18 normal volunteers. The dual-contour propagation algorithm was used to propagate contours throughout the cardiac cycle. The results were compared to those obtained with single-contour propagation (using either end-diastolic or end-systolic contours) and commercially available software. We then used the dual-contour propagation technique to measure peak ejection rate (PER) and peak early diastolic and late diastolic filling rates (ePFR and aPFR) in all normal volunteers and hypertensive patients. Results Compared to single-contour propagation methods and the commercial method, VTC by dual-contour propagation showed significantly better agreement with manually-derived VTC. Ejection and filling rates by dual-contour propagation agreed with manual (dual-contour – manual PER: -0.12 ± 0.08; ePFR: -0.07 ± 0.07; aPFR: 0.06 ± 0.03 EDV/s, all P = NS). However, the time for the manual method was ~4 hours per study versus ~7 minutes for dual-contour propagation. LV systolic function measured by LVEF and PER did not differ between normal volunteers and hypertensive patients. However, ePFR was lower in hypertensive patients vs. normal volunteers, while aPFR was higher, indicative of altered diastolic filling rates in hypertensive patients. Conclusion Dual-propagated contours can accurately measure both systolic and diastolic volumetric indices that can be applied in a routine clinical CMR environment. With dual-contour propagation, the user interaction that is routinely performed to measure LVEF is leveraged to obtain additional clinically relevant parameters. PMID:19674481

Feng, Wei; Nagaraj, Hosakote; Gupta, Himanshu; Lloyd, Steven G; Aban, Inmaculada; Perry, Gilbert J; Calhoun, David A; Dell'Italia, Louis J; Denney, Thomas S

2009-01-01

245

Assessment of cardiac pathology by point-of-care ultrasonography performed by a novice examiner is comparable to the gold standard  

PubMed Central

Background The aim of the study was to compare the diagnostic accuracy of point-of-care cardiac ultrasonography performed by a novice examiner against results from a specialist in cardiology with expert skills in echocardiography, with regard to the assessment of six clinically relevant cardiac conditions in a population of ward patients from the Department of Cardiology or the Department of Cardiothoracic Surgery. Methods Cardiac ultrasonography was performed by a novice examiner at the bedside and images were interpreted in a point-of-care context with dichotomous outcomes (yes/no). Six outcome categories were defined: 1) pericardial effusion (?10 mm), 2) left ventricular dilatation (?62 mm), 3) right ventricular dilatation (?42 mm or???left ventricular diameter), 4) left ventricular hypertrophy (?13 mm), 5) left ventricular failure (EF???40%), 6) aortic stenosis (maximum flow velocity ?3 m/s). The examiner was blinded to the patients’ medical history and results from previous echocardiographic examinations. Results from the interpreted point-of-care ultrasonography examination were compared with echocardiographic diagnosis made by a specialist in cardiology. Results A total of 102 medical and surgical patients were included. Assessments were made in six categories totalling 612 assessments. There was agreement between the novice examiner and the specialist in 95.6% of the cases; overall sensitivity was 0.91 and specificity was 0.97. Positive predictive value was 0.92 and negative predictive value was 0.97. Kappa statistics showed good agreement between observers (?=0.88). Conclusions This study showed that a novice examiner was able to detect common and significant heart pathology in six different categories with good accuracy using POC ultrasonography. PMID:24330752

2013-01-01

246

Multiscale Entropy Analysis of EEG for Assessment of Post-Cardiac Arrest Neurological Recovery Under Hypothermia in Rats  

Microsoft Academic Search

Neurological complications after cardiac arrest (CA) can be fatal. Although hypothermia has been shown to be beneficial, understanding the mechanism and establishing neurological outcomes remains challenging because effects of CA and hypothermia are not well characterized. This paper aims to analyze EEG (and the alpha-rhythms) using multiscale entropy (MSE) to demonstrate the ability of MSE in tracking changes due to

Xiaoxu Kang; Xiaofeng Jia; Romergryko G. Geocadin; Nitish V. Thakor; Anil Maybhate

2009-01-01

247

Nonexercise cardiac stress testing  

SciTech Connect

Many patients who require evaluation for coronary artery disease are unable to undergo exercise stress testing because of physiologic or psychological limitations. Drs Vacek and Baldwin describe three alternative methods for assessment of cardiac function in these patients, all of which have high levels of diagnostic sensitivity and specificity. 23 references.

Vacek, J.L.; Baldwin, T. (Univ. of Kansas Medical Center, Kansas City (USA))

1989-09-15

248

Cardiac rhabdomyosarcoma.  

PubMed

Cardiac sarcoma is a very rare neoplasm and is difficult to diagnose. The case of a 51-year-old man with a left atrial tumour, locally recurrent three months after its surgical removal, is presented. Computed tomography showed metastatic spread to the lung parenchyma. On revised histology, the mass extirpated was a sarcoma. Because of the metastatic spread, further therapy was symptomatic only; the patient died 15 months after the first manifestation of his problems. Immunohistochemical staining confirmed cardiac rhabdomyosarcoma with metastatic spread to the lungs. Difficulty in diagnosing and treating cardiac tumours is discussed. PMID:20428274

Chlumský, J; Holá, D; Hlavácek, K; Michal, M; Svec, A; Spatenka, J; Dusek, J

2001-01-01

249

Current trends in cardiac CT in children.  

PubMed

Cardiac CT is increasingly utilized in children thanks to advanced scan techniques reducing cardiac and respiratory motion artifacts. Consequently, clinical indications of cardiac CT are not confined to the extracardiac evaluation and extended further to the assessment of intracardiac structures, coronary arteries, ventricular volumetry, and ventricular function. In addition, dual-energy CT allows the assessment of regional lung perfusion and ventilation. Four-dimensional airway evaluation is also useful and may be added to cardiac CT protocols. At the same time, a favorable risk-benefit ratio of cardiac CT can be achieved by means of various dose-saving techniques. Therefore, flexible scan techniques with minimal motion artifacts, low dose techniques without compromising excellent image quality, and extended clinical applications towards truly cardiac assessments constitute current trends in cardiac CT in children. PMID:23104372

Goo, Hyun Woo

2013-11-01

250

[Cardiac angiosarcoma].  

PubMed

The paper outlines the authors'case of cardiac angiosarcoma. It provides the gross and microscopic characteristics of this tumor and procedures for its clinical and immunomorphological diagnosis. PMID:21695990

Kir'ianov, N A; Terekhov, M V; Sukhanov, S A; Lozhkin, E A; Nikolaeva, N B

2011-01-01

251

Cardiac Cephalalgia  

Microsoft Academic Search

We report a patient with cardiac cephalalgia and review reported cases from the English-language literature based on the new diagnostic criteria published in the International Classification of Headache Disorders, ed 2. Twenty-two patients, including ours, with headaches of cardiac origin were reviewed. The cases fit three of the four new criteria well: Criteria B (acute myocardial ischemia has occurred, 100%),

Shih-Pin Chen; Jong-Ling Fuh; Wen-Chung Yu; Shuu-Jiun Wang

2004-01-01

252

Cardiac factors in orthostatic hypotension  

NASA Astrophysics Data System (ADS)

Cardiac function is determined by preload, afterload, heart rate and contractility. During orthostatic stress, the footward blood shift is compensated for by an increase of afterload. LBNP is widely used to analyze effects of volume displacement during orthostatic stress. Comparisons of invasive ( right heart catheterization) and non-invasive approach (echocardiography) yielded similar changes. Preload and afterload change with graded LBNP, heart rate increases, and stroke volume and cardiac output decrease. Thus, the working point on the left ventricular function curve is shifted to the left and downward, similar to hypovolemia. However, position on the Frank-Starling curve, the unchanged ejection fraction, and the constant Vcf indicate a normal contractile state during LBNP. A decrease of arterial oxygen partial pressure during LBNP shwos impaired ventilation/perfusion ratio. Finally, LBNP induced cardiac and hemodynamic changes can be effectively countermeasured by dihydroergotamine, a potent venoconstrictor. Comparison of floating catheter data with that of echocardiography resulted in close correlation for cardiac output and stroke volume. In addition, cardiac dimensions changed in a similar way during LBNP. From our findings, echocardiography as a non-invasive procedure can reliably used in LBNP and orthostatic stress tests. Some informations can be obtained on borderline values indicating collaps or orthostatic syncope. Early fainters can be differentiated from late fainters by stroke volume changes.

Löllgen, H.; Dirschedl, P.; Koppenhagen, K.; Klein, K. E.

253

Elevated miR-499 Levels Blunt the Cardiac Stress Response  

PubMed Central

Background The heart responds to myriad stresses by well-described transcriptional responses that involve long-term changes in gene expression as well as more immediate, transient adaptations. MicroRNAs quantitatively regulate mRNAs and thus may affect the cardiac transcriptional output and cardiac function. Here we investigate miR-499, a microRNA embedded within a ventricular-specific myosin heavy chain gene, which is expressed in heart and skeletal muscle. Methodology/Principal Findings We assessed miR-499 expression in human tissue to confirm its potential relevance to human cardiac gene regulation. Using a transgenic mouse model, we found that elevated miR-499 levels caused cellular hypertrophy and cardiac dysfunction in a dose-dependent manner. Global gene expression profiling revealed altered levels of the immediate early stress response genes (Egr1, Egr2 and Fos), ß-myosin heavy chain (Myh7), and skeletal muscle actin (Acta1). We verified the effect of miR-499 on the immediate early response genes by miR-499 gain- and loss-of-function in vitro. Consistent with a role for miR-499 in blunting the response to cardiac stress, asymptomatic miR-499-expressing mice had an impaired response to pressure overload and accentuated cardiac dysfunction. Conclusions Elevated miR-499 levels affect cardiac gene expression and predispose to cardiac stress-induced dysfunction. miR-499 may titrate the cardiac response to stress in part by regulating the immediate early gene response. PMID:21573063

Shieh, Joseph T. C.; Huang, Yu; Gilmore, Jacqueline; Srivastava, Deepak

2011-01-01

254

Prehospital randomised assessment of a mechanical compression device in cardiac arrest (PaRAMeDIC) trial protocol  

Microsoft Academic Search

BACKGROUND: Survival after out-of-hospital cardiac arrest is closely linked to the quality of CPR, but in real life, resuscitation during prehospital care and ambulance transport is often suboptimal. Mechanical chest compression devices deliver consistent chest compressions, are not prone to fatigue and could potentially overcome some of the limitations of manual chest compression. However, there is no high-quality evidence that

Gavin D Perkins; Malcolm Woollard; Matthew W Cooke; Charles Deakin; Jessica Horton; Ranjit Lall; Sarah E Lamb; Chris McCabe; Tom Quinn; Anne Slowther; Simon Gates

2010-01-01

255

About Cardiac Arrest  

MedlinePLUS

... High Blood Pressure Tools & Resources Stroke More About Cardiac Arrest Updated:Sep 10,2014 What is cardiac arrest? ... to heart disease and stroke. Start exploring today ! Cardiac Arrest • Home • About Cardiac Arrest • Understand Your Risk for ...

256

Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: a study to assess the drug's cardiac ion channel profile.  

PubMed

The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licensed as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Nav1.5 sodium and Cav1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (? 10 ?M) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. PMID:23707769

Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K; Lukacs, Peter; Gawali, Vaibhavkumar S; Todt, Hannes; Hilber, Karlheinz; Sandtner, Walter

2013-12-01

257

Anti-addiction drug ibogaine inhibits voltage-gated ionic currents: A study to assess the drug's cardiac ion channel profile?  

PubMed Central

The plant alkaloid ibogaine has promising anti-addictive properties. Albeit not licenced as a therapeutic drug, and despite hints that ibogaine may perturb the heart rhythm, this alkaloid is used to treat drug addicts. We have recently reported that ibogaine inhibits human ERG (hERG) potassium channels at concentrations similar to the drugs affinity for several of its known brain targets. Thereby the drug may disturb the heart's electrophysiology. Here, to assess the drug's cardiac ion channel profile in more detail, we studied the effects of ibogaine and its congener 18-Methoxycoronaridine (18-MC) on various cardiac voltage-gated ion channels. We confirmed that heterologously expressed hERG currents are reduced by ibogaine in low micromolar concentrations. Moreover, at higher concentrations, the drug also reduced human Nav1.5 sodium and Cav1.2 calcium currents. Ion currents were as well reduced by 18-MC, yet with diminished potency. Unexpectedly, although blocking hERG channels, ibogaine did not prolong the action potential (AP) in guinea pig cardiomyocytes at low micromolar concentrations. Higher concentrations (? 10 ?M) even shortened the AP. These findings can be explained by the drug's calcium channel inhibition, which counteracts the AP-prolonging effect generated by hERG blockade. Implementation of ibogaine's inhibitory effects on human ion channels in a computer model of a ventricular cardiomyocyte, on the other hand, suggested that ibogaine does prolong the AP in the human heart. We conclude that therapeutic concentrations of ibogaine have the propensity to prolong the QT interval of the electrocardiogram in humans. In some cases this may lead to cardiac arrhythmias. PMID:23707769

Koenig, Xaver; Kovar, Michael; Rubi, Lena; Mike, Agnes K.; Lukacs, Peter; Gawali, Vaibhavkumar S.; Todt, Hannes; Hilber, Karlheinz; Sandtner, Walter

2013-01-01

258

Assessment of the dose distribution inside a cardiac cath lab using TLD measurements and Monte Carlo simulations  

NASA Astrophysics Data System (ADS)

Over the last decade, there was a substantial increase in the number of interventional cardiology procedures worldwide, and the corresponding ionizing radiation doses for both the medical staff and patients became a subject of concern. Interventional procedures in cardiology are normally very complex, resulting in long exposure times. Also, these interventions require the operator to work near the patient and, consequently, close to the primary X-ray beam. Moreover, due to the scattered radiation from the patient and the equipment, the medical staff is also exposed to a non-uniform radiation field that can lead to a significant exposure of sensitive body organs and tissues, such as the eye lens, the thyroid and the extremities. In order to better understand the spatial variation of the dose and dose rate distributions during an interventional cardiology procedure, the dose distribution around a C-arm fluoroscopic system, in operation in a cardiac cath lab at Portuguese Hospital, was estimated using both Monte Carlo (MC) simulations and dosimetric measurements. To model and simulate the cardiac cath lab, including the fluoroscopic equipment used to execute interventional procedures, the state-of-the-art MC radiation transport code MCNPX 2.7.0 was used. Subsequently, Thermo-Luminescent Detector (TLD) measurements were performed, in order to validate and support the simulation results obtained for the cath lab model. The preliminary results presented in this study reveal that the cardiac cath lab model was successfully validated, taking into account the good agreement between MC calculations and TLD measurements. The simulated results for the isodose curves related to the C-arm fluoroscopic system are also consistent with the dosimetric information provided by the equipment manufacturer (Siemens). The adequacy of the implemented computational model used to simulate complex procedures and map dose distributions around the operator and the medical staff is discussed, in view of the optimization principle (and the associated ALARA objective), one of the pillars of the international system of radiological protection.

Baptista, M.; Teles, P.; Cardoso, G.; Vaz, P.

2014-11-01

259

Cardiac Regeneration  

PubMed Central

The heart is a pump that is comprised of cardiac myocytes and other cell types and whose proper function is critical to quality of life. The ability to trigger regeneration of heart muscle following injury eludes adult mammals, a deficiency of great clinical impact. Major research efforts are attempting to change this through advances in cell therapy or activating endogenous regenerative mechanisms that exist only early in life. By contrast with mammals, lower vertebrates like zebrafish demonstrate an impressive natural capacity for cardiac regeneration throughout life. This review will cover recent progress in the field of heart regeneration with a focus on endogenous regenerative capacity and its potential manipulation. PMID:22449849

Choi, Wen-Yee; Poss, Kenneth D.

2012-01-01

260

The Role of Cardiac Computed Tomography in Cardiac Surgery  

Microsoft Academic Search

Electrocardiogram-synchronized multidetector computed tomography (MDCT) allows for a comprehensive assessment of the heart\\u000a that facilitates planning and performing surgical procedures. MDCT permits for a high-resolution three-dimensional visualization\\u000a of cardiac structures along with a simultaneous evaluation of cardiac function. Used for the preoperative work-up MDCT enables\\u000a the non-invasive evaluation of the coronary arteries. With its high negative predictive value MDCT can

Alexander Lembcke

261

Predicting cardiac complications in patients undergoing non-cardiac surgery  

Microsoft Academic Search

The authors prospectively studied 455 consecutive patients referred to the general medical consultation service for cardiac\\u000a risk assessment prior to non-cardiac surgery, in order to validate a previously derived multifactorial index in their clinical\\u000a setting. They also tested a version of the index that they had modified to reflect factors they believed to be important.\\u000a For patients undergoing major surgery,

Allan S. Detsky; Howard B. Abrams; John R. McLaughlin; Daniel J. Drucker; Zion Sasson; Nancy Johnston; J. Gerald Scott; Nicholas Forbath; Joseph R. Hilliard

1986-01-01

262

Cardiac function after acute support with direct mechanical ventricular actuation in chronic heart failure.  

PubMed

Direct mechanical ventricular actuation (DMVA) exerts direct cardiac compression/decompression and does not require blood contact. The safety and effects of DMVA support in chronically dysfunctional beating hearts in vivo have not been established. This study evaluated hemodynamics and load-independent systolic/diastolic cardiac function before/after acute support (2 hours) using DMVA in small hearts with induced chronic failure. Chronic heart failure was created in seven small dogs (15 ± 2 kg) via either serial coronary microembolizations or right-ventricular overdrive pacing. Dogs were instrumented to measure cardiac output, hemodynamic pressures, left ventricular volumes for pressure-volume analysis via preload reduction. Temporary cardiac support using a DMVA device was instituted for 2 hours. Hemodynamic and mechanical assessments, including dobutamine dose-responses, were compared both before and after support. Hemodynamic indices were preserved with support. Both left-ventricular systolic and diastolic function were improved postsupport, as the slopes of the preload-recruitable stroke work (+29 ± 7%, p < 0.05) and the end-diastolic pressure-volume relationship (EDPVR: -28 ± 9%, p < 0.05) improved post-DMVA support. Diastolic/systolic myocardial reserve, as assessed by responsiveness to dobutamine challenges, was preserved after DMVA support. Short-term DMVA support can safely and effectively sustain hemodynamics, whereas triggering favorable effects on cardiac function in the setting of chronic heart failure. In particular, DMVA support preserved load-independent diastolic function and reserve. PMID:25238499

McConnell, Patrick I; Anstadt, Mark P; Del Rio, Carlos L; Preston, Thomas J; Ueyama, Yukie; Youngblood, Brad L

2014-01-01

263

The role of echocardiography in the assessment of cardiac function in weightlessness-Our experience during parabolic flights.  

PubMed

Parabolic flight (PF) elicits changes in hydrostatic pressure gradients, resulting in increase (at 0Gz) or decrease (at 1.8Gz) in cardiac preload. The magnitude of these changes on left ventricular (LV) and atrial (LA) volumes, as well as on myocardial velocities, strain and strain rates, is largely unknown. Using real-time 3D (RT3DE) and Doppler tissue echocardiographic imaging (DTI) during PF in normal subjects in standing position, we showed that both LV and LA volumes were decreased at 1.8Gz and increased at 0Gz by about 20% and 40%, respectively. Previous 2D or M-mode studies underestimated such changes. Also, preload dependence was confirmed for systolic and diastolic velocities, and peak systolic strain, while strain rates were preload independent, probably reflecting intrinsic myocardial properties. Low body negative pressure at -50mmHg applied during 0Gz was effective in restoring 1Gz levels. RT3DE and DTI during PF are feasible, allowing the evaluation of the cardiac function under different loading conditions. PMID:19616134

Caiani, E G; Weinert, L; Lang, R M; Vaïda, P

2009-10-01

264

Cardiac Rehabilitation  

MedlinePLUS

Cardiac rehabilitation (rehab) is a medically supervised program to help people who have A heart attack Angioplasty or coronary artery bypass grafting for coronary heart disease A heart valve repair or replacement A heart transplant or a lung transplant Angina Heart failure The ...

265

d-Propranolol protects against oxidative stress and progressive cardiac dysfunction in iron overloaded rats.  

PubMed

d-Propranolol (d-Pro: 2-8 mg·(kg body mass)(-1)·day(-1)) protected against cardiac dysfunction and oxidative stress during 3-5 weeks of iron overload (2 mg Fe-dextran·(g body mass)(-1)·week(-1)) in Sprague-Dawley rats. At 3 weeks, hearts were perfused in working mode to obtain baseline function; red blood cell glutathione, plasma 8-isoprostane, neutrophil basal superoxide production, lysosomal-derived plasma N-acetyl-?-galactosaminidase (NAGA) activity, ventricular iron content, and cardiac iron deposition were assessed. Hearts from the Fe-treated group of rats exhibited lower cardiac work (26%) and output (CO, 24%); end-diastolic pressure rose 1.8-fold. Further, glutathione levels increased 2-fold, isoprostane levels increased 2.5-fold, neutrophil superoxide increased 3-fold, NAGA increased 4-fold, ventricular Fe increased 4.9-fold; and substantial atrial and ventricular Fe-deposition occurred. d-Pro (8 mg) restored heart function to the control levels, protected against oxidative stress, and decreased cardiac Fe levels. After 5 weeks of Fe treatment, echocardiography revealed that the following were depressed: percent fractional shortening (%FS, 31% lower); left ventricular (LV) ejection fraction (LVEF, 17%), CO (25%); and aortic pressure maximum (P(max), 24%). Mitral valve E/A declined by 18%, indicating diastolic dysfunction. Cardiac CD11b+ infiltrates were elevated. Low d-Pro (2 mg) provided modest protection, whereas 4-8 mg greatly improved LVEF (54%-75%), %FS (51%-81%), CO (43%-78%), P(max) (56%-100%), and E/A >100%; 8 mg decreased cardiac inflammation. Since d-Pro is an antioxidant and reduces cardiac Fe uptake as well as inflammation, these properties may preserve cardiac function during Fe overload. PMID:22913465

Kramer, Jay H; Spurney, Christopher F; Iantorno, Micaela; Tziros, Constantine; Chmielinska, Joanna J; Mak, I Tong; Weglicki, William B

2012-09-01

266

Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly.  

PubMed

Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with acromegaly. PMID:23553172

Dural, Muhammet; Kabakc?, Giray; C?nar, Ne?e; Erba?, Tomris; Canpolat, U?ur; Gürses, Kadri Murat; Tokgözo?lu, Lale; Oto, Ali; Kaya, Ergün Bar??; Yorgun, Hikmet; Sahiner, Levent; Da?delen, Selçuk; Aytemir, Kudret

2014-04-01

267

A cortical potential reflecting cardiac function  

PubMed Central

Emotional trauma and psychological stress can precipitate cardiac arrhythmia and sudden death through arrhythmogenic effects of efferent sympathetic drive. Patients with preexisting heart disease are particularly at risk. Moreover, generation of proarrhythmic activity patterns within cerebral autonomic centers may be amplified by afferent feedback from a dysfunctional myocardium. An electrocortical potential reflecting afferent cardiac information has been described, reflecting individual differences in interoceptive sensitivity (awareness of one's own heartbeats). To inform our understanding of mechanisms underlying arrhythmogenesis, we extended this approach, identifying electrocortical potentials corresponding to the cortical expression of afferent information about the integrity of myocardial function during stress. We measured changes in cardiac response simultaneously with electroencephalography in patients with established ventricular dysfunction. Experimentally induced mental stress enhanced cardiovascular indices of sympathetic activity (systolic blood pressure, heart rate, ventricular ejection fraction, and skin conductance) across all patients. However, the functional response of the myocardium varied; some patients increased, whereas others decreased, cardiac output during stress. Across patients, heartbeat-evoked potential amplitude at left temporal and lateral frontal electrode locations correlated with stress-induced changes in cardiac output, consistent with an afferent cortical representation of myocardial function during stress. Moreover, the amplitude of the heartbeat-evoked potential in the left temporal region reflected the proarrhythmic status of the heart (inhomogeneity of left ventricular repolarization). These observations delineate a cortical representation of cardiac function predictive of proarrhythmic abnormalities in cardiac repolarization. Our findings highlight the dynamic interaction of heart and brain in stress-induced cardiovascular morbidity. PMID:17420478

Gray, Marcus A.; Taggart, Peter; Sutton, Peter M.; Groves, David; Holdright, Diana R.; Bradbury, David; Brull, David; Critchley, Hugo D.

2007-01-01

268

Adaptive detection of missed text areas in OCR outputs: application to the automatic assessment of OCR quality in mass digitization projects  

NASA Astrophysics Data System (ADS)

The French National Library (BnF*) has launched many mass digitization projects in order to give access to its collection. The indexation of digital documents on Gallica (digital library of the BnF) is done through their textual content obtained thanks to service providers that use Optical Character Recognition softwares (OCR). OCR softwares have become increasingly complex systems composed of several subsystems dedicated to the analysis and the recognition of the elements in a page. However, the reliability of these systems is always an issue at stake. Indeed, in some cases, we can find errors in OCR outputs that occur because of an accumulation of several errors at different levels in the OCR process. One of the frequent errors in OCR outputs is the missed text components. The presence of such errors may lead to severe defects in digital libraries. In this paper, we investigate the detection of missed text components to control the OCR results from the collections of the French National Library. Our verification approach uses local information inside the pages based on Radon transform descriptors and Local Binary Patterns descriptors (LBP) coupled with OCR results to control their consistency. The experimental results show that our method detects 84.15% of the missed textual components, by comparing the OCR ALTO files outputs (produced by the service providers) to the images of the document.

Ben Salah, Ahmed; Ragot, Nicolas; Paquet, Thierry

2013-01-01

269

Estimates of Embodied Global Energy and Air-Emission Intensities of Japanese Products for Building a Japanese Input-Output Life Cycle Assessment Database with a Global System Boundary  

PubMed Central

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input–output LCA method with a global link input–output model that defines a global system boundary grounded in a simplified multiregional input–output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input–output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains. PMID:22881452

2012-01-01

270

Estimates of embodied global energy and air-emission intensities of Japanese products for building a Japanese input-output life cycle assessment database with a global system boundary.  

PubMed

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input-output LCA method with a global link input-output model that defines a global system boundary grounded in a simplified multiregional input-output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input-output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains. PMID:22881452

Nansai, Keisuke; Kondo, Yasushi; Kagawa, Shigemi; Suh, Sangwon; Nakajima, Kenichi; Inaba, Rokuta; Tohno, Susumu

2012-08-21

271

Cardiac mechanics: Physiological, clinical, and mathematical considerations  

NASA Technical Reports Server (NTRS)

Recent studies concerning the basic physiological and biochemical principles underlying cardiac muscle contraction, methods for the assessment of cardiac function in the clinical situation, and mathematical approaches to cardiac mechanics are presented. Some of the topics covered include: cardiac ultrastructure and function in the normal and failing heart, myocardial energetics, clinical applications of angiocardiography, use of echocardiography for evaluating cardiac performance, systolic time intervals in the noninvasive assessment of left ventricular performance in man, evaluation of passive elastic stiffness for the left ventricle and isolated heart muscle, a conceptual model of myocardial infarction and cardiogenic shock, application of Huxley's sliding-filament theory to the mechanics of normal and hypertrophied cardiac muscle, and a rheological modeling of the intact left ventricle. Individual items are announced in this issue.

Mirsky, I. (editor); Ghista, D. N.; Sandler, H.

1974-01-01

272

Cardiac surgery outcomes.  

PubMed

Accrediting organizations and payers are demanding valid and reliable data that demonstrate the value of services. Federal agencies, healthcare industry groups, and healthcare watchdog groups are increasing the demand for public access to outcomes data. A new and growing outcomes dynamic is the information requested by prospective patients in an increasingly consumer-oriented business. Patients demand outcomes, and resources are developing to meet these demands. Physicians are increasingly confronted with requests for information about their mortality and morbidity rates, malpractice suits, and disciplinary actions received. For example, in Virginia, prospective patients have access to data provided by the nonprofit group Virginia Health Information. After numerous resolutions by the Virginia Senate since 1999, the prospective Virginia medical consumer now has access to several annual publications: Virginia Hospitals: A Consumer's Guide, 1999 Annual Report and Strategic Plan Update, and the 1999 Industry Report: Virginia Hospitals and Nursing Facilities. Consumers have access to cardiac outcomes data stratified by hospital, gender, and cardiac service line (cardiac surgery, noninvasive cardiology, and invasive cardiology). This is particularly relevant to IHI because Virginia Health Information specifically targets cardiac care. IHI has a sizable investment in cardiovascular outcomes and has found outcomes measurement and research are key to providing quality care. IHI's goal is to move from an outcomes management model to a disease management model. The hope is to incorporate all aspects of the patient's continuum of care, from preoperative and diagnostic services through cardiac interventions to postoperative rehabilitation. Furthermore, every step along the way will be supported with functional status and quality of life assessments. Although these goals are ambitious and expensive, the return on investment is high. PMID:14618772

Halpin, Linda S; Barnett, Scott D; Beachy, Jim

2003-01-01

273

Cardiac optogenetics  

PubMed Central

Optogenetics is an emerging technology for optical interrogation and control of biological function with high specificity and high spatiotemporal resolution. Mammalian cells and tissues can be sensitized to respond to light by a relatively simple and well-tolerated genetic modification using microbial opsins (light-gated ion channels and pumps). These can achieve fast and specific excitatory or inhibitory response, offering distinct advantages over traditional pharmacological or electrical means of perturbation. Since the first demonstrations of utility in mammalian cells (neurons) in 2005, optogenetics has spurred immense research activity and has inspired numerous applications for dissection of neural circuitry and understanding of brain function in health and disease, applications ranging from in vitro to work in behaving animals. Only recently (since 2010), the field has extended to cardiac applications with less than a dozen publications to date. In consideration of the early phase of work on cardiac optogenetics and the impact of the technique in understanding another excitable tissue, the brain, this review is largely a perspective of possibilities in the heart. It covers the basic principles of operation of light-sensitive ion channels and pumps, the available tools and ongoing efforts in optimizing them, overview of neuroscience use, as well as cardiac-specific questions of implementation and ideas for best use of this emerging technology in the heart. PMID:23457014

2013-01-01

274

Cardiac Surgery  

PubMed Central

Well into the first decades of the 20th century, medical opinion held that any surgical attempts to treat heart disease were not only misguided, but unethical. Despite such reservations, innovative surgeons showed that heart wounds could be successfully repaired. Then, extracardiac procedures were performed to correct patent ductus arteriosus, coarctation of the aorta, and tetralogy of Fallot. Direct surgery on the heart was accomplished with closed commissurotomy for mitral stenosis. The introduction of the heart-lung machine and cardiopulmonary bypass enabled the surgical treatment of other congenital and acquired heart diseases. Advances in aortic surgery paralleled these successes. The development of coronary artery bypass grafting greatly aided the treatment of coronary heart disease. Cardiac transplantation, attempts to use the total artificial heart, and the application of ventricular assist devices have brought us to the present day. Although progress in the field of cardiovascular surgery appears to have slowed when compared with the halcyon times of the past, substantial challenges still face cardiac surgeons. It can only be hoped that sufficient resources and incentive can carry the triumphs of the 20th century into the 21st. This review covers past developments and future opportunities in cardiac surgery. PMID:22163121

Weisse, Allen B.

2011-01-01

275

Cardiac cone-beam CT  

SciTech Connect

This doctoral thesis addresses imaging of the heart with retrospectively gated helical cone-beam computed tomography (CT). A thorough review of the CT reconstruction literature is presented in combination with a historic overview of cardiac CT imaging and a brief introduction to other cardiac imaging modalities. The thesis includes a comprehensive chapter about the theory of CT reconstruction, familiarizing the reader with the problem of cone-beam reconstruction. The anatomic and dynamic properties of the heart are outlined and techniques to derive the gating information are reviewed. With the extended cardiac reconstruction (ECR) framework, a new approach is presented for the heart-rate-adaptive gated helical cardiac cone-beam CT reconstruction. Reconstruction assessment criteria such as the temporal resolution, the homogeneity in terms of the cardiac phase, and the smoothness at cycle-to-cycle transitions are developed. Several reconstruction optimization approaches are described: An approach for the heart-rate-adaptive optimization of the temporal resolution is presented. Streak artifacts at cycle-to-cycle transitions can be minimized by using an improved cardiac weighting scheme. The optimal quiescent cardiac phase for the reconstruction can be determined automatically with the motion map technique. Results for all optimization procedures applied to ECR are presented and discussed based on patient and phantom data. The ECR algorithm is analyzed for larger detector arrays of future cone-beam systems throughout an extensive simulation study based on a four-dimensional cardiac CT phantom. The results of the scientific work are summarized and an outlook proposing future directions is given. The presented thesis is available for public download at www.cardiac-ct.net.

Manzke, Robert [University of London (King's College) (United Kingdom)]. E-mail: robert.manzke@philips.com

2005-10-15

276

Visualization of Model Output  

NSDL National Science Digital Library

Visualization of output from mathematical or statistical models is one of the best ways to introduce introductory geoscience students to the results and behavior of sophisticated models. Example of good sites ...

277

What Is an Output?  

Microsoft Academic Search

A recurrent idea in the history of psychology is that one is conscious of outputs but not of the complex processes underlying the generation of outputs, which is evident in the out-of-the-blue, “eureka-like” experiences associated with intuition. We examine how this idea may suffer from a logical fallacy and may thus have inadvertently hindered progress on the study of the

Ezequiel Morsella; John A. Bargh

2010-01-01

278

An assessment of desflurane for use during cardiac electrophysiological study and radiofrequency ablation of supraventricular dysrhythmias in children.  

PubMed

Desflurane has several properties making it a desirable agent for use in electrophysiological studies (EPS) for diagnosis and treatment of cardiac dysrhythmias. We studied 47 children, mean age 12.8+/-4.6 years, mean weight 52.9+/-24.0 kg, with clinical history of supra- ventricular tachycardia (SVT) during EPS using desflurane in a crossover comparison with fentanyl. The patients served as their own controls. All received oral premedication with lorazepam, and intravenous induction with thiopentone, rocuronium, and oxygen. Group 1 (n=24) were administered fentanyl 10 microg.kg-1 bolus i.v. with an infusion of 3 microg.kg-1.h-1 during initial EPS. Fentanyl was discontinued and desflurane, 6% endtidal, was administered and the EPS repeated. Group 2 (n=23) were initially administered 6% desflurane after induction, and following EPS the desflurane was discontinued and the patients administered fentanyl 3 microg.kg-1 bolus and EPS repeated (explanations of EPS abbreviations are provided). Desflurane reduced the mean arterial pressure (MAP) in all patients. In Group 1, desflurane shortened the sinus cycle length (SCL), i.e. increasing the heart rate, and atrial effective refractory period (AERP) while Group 2 demonstrated no such effect on AERP. There were no other significant differences between fentanyl or desflurane techniques in terms of EPS measurements. SVT was inducible with both agents in both groups. Desflurane seems an acceptable agent for use during EPS procedures. PMID:10736078

Schaffer, M S; Snyder, A M; Morrison, J E

2000-01-01

279

The central axis prosthetic cardiac valve: an in vitro study of pressure drop assessment under steady-state flow conditions.  

PubMed

In this work, a new mechanical prosthetic heart valve, the central axis valve, is presented. This new prosthesis has been tested in vitro, and compared with four other common prosthetic cardiac valves (Starr-Edwards 6120, Bjork-Shiley monostrut, Medtronic-Hall, and St Jude Medical valves). All valves studied have the same orifice diameter of 22 mm. The prostheses were installed inside a transparent mitral test chamber, which enables pressure drop measurement to be made under steady-state flow conditions using a blood analogue fluid. Pressure drop loss is one important factor affecting the overall performance of a prosthetic heart valve. Steady-state flow tests are essential to predict certain flow characteristics and pressure gradient loss before more complicated, expensive, and difficult-to-interpret pulsatile flow tests are conducted. All experiments were performed in vitro and at steady volumetric flow rates of 10 to 30 l/min. The Starr-Edwards SE 6120 showed the highest values for pressure drop. The St Jude Medical valve offers the minimum resistance to flow. The central axis valve comes second to the Starr Edwards valve for this type of measurement. The new valve is promising. A complete valve evaluation programme, covering initial conceptional design through to clinical use, is in progress. Materials for the fabrication of the new valve are also under consideration. PMID:2296172

Haggag, Y A

1990-01-01

280

Reproducibility of linear cardiac output measurement by Doppler ultrasound alone  

Microsoft Academic Search

Inclusion of a pig aorta in an artificial circulation with pulsed blood flow allowed correlation of minute distance, measured in the aorta by Doppler ultrasound, and absolute blood flow, measured by timed blood-volume collection. The correlation coefficient was 0.99 with a standard error of prediction that was 5.4% of the minute distance predicted at a standard flow rate of 5

F M McLennan; N E Haites; J D Mackenzie; M K Daniel; J M Rawles

1986-01-01

281

The New York State cardiac registries: history, contributions, limitations, and lessons for future efforts to assess and publicly report healthcare outcomes.  

PubMed

In 1988, the New York State Health Commissioner was confronted with hospital-level data demonstrating very large, multiple-year, interhospital variations in short-term mortality and complications for cardiac surgery. The concern with the extent to which these differences were due to variations in patients' pre-surgical severity of illness versus hospitals' quality of care led to the development of clinical registries for cardiac surgery in 1989 and for percutaneous coronary interventions in 1992 in New York. In 1990, the Department of Health released hospitals' risk-adjusted cardiac surgery mortality rates for the first time, and shortly thereafter, similar data were released for hospitals and physicians for percutaneous coronary interventions, cardiac valve surgery, and pediatric cardiac surgery (only hospital data). This practice is still ongoing. The purpose of this communication is to relate the history of this initiative, including changes or purported changes that have occurred since the public release of cardiac data. These changes include decreases in risk-adjusted mortality, cessation of cardiac surgery in New York by low-volume and high-mortality surgeons, out-of-state referral or avoidance of cardiac surgery/angioplasty for high-risk patients, alteration of contracting choices by insurance companies, and modifications in market share of cardiac hospitals. Evidence related to these impacts is reviewed and critiqued. This communication also includes a summary of numerous studies that used New York's cardiac registries to examine a variety of policy issues regarding the choice and use of cardiac procedures, the comparative effectiveness of competing treatment options, and the examination of the relationship among processes, structures, and outcomes of cardiac care. PMID:22698487

Hannan, Edward L; Cozzens, Kimberly; King, Spencer B; Walford, Gary; Shah, Nirav R

2012-06-19

282

Linear accelerator output variability.  

PubMed

The Wellington Cancer Centre is equipped with two matched linear accelerators (Varian 2100CD) linear accelerators (identified as SN1027 and SN42). Each morning, before treatments commence, a radiation therapist carries out an output constancy check of the radiation output and every fortnight a physicist measures, in a phantom, the delivered radiation dose to check on the machine calibration. The daily output checks have been recorded into a database (Argus QA for Radiation Oncology) since August 1997 and in June 1998 the fortnightly calibration measurements were added. The information in the database, up to April 2003, has been analysed to consider the quality of the daily constancy checks as compared with the fortnightly calibration measurements and whether the data contains useful information on machine performance. After allowance for the effects of machine recalibration the fortnightly calibration measurements had an average standard deviation of 0.4% and the daily constancy checks 0.8%. The daily constancy checks had a greater number of large deviations than would be expected assuming a normal distribution and were not a good predictor of the need for a recalibration. The fortnightly calibration measurements with a much lower spread give a reliable indication of the need for a recalibration allowing the adoption of a +/- 1% tolerance. Over the period analysed one accelerator (SN42) was relatively stable with the output generally drifting between +/- 1% while the other (SN1027) had a consistent increase in the average output of about 2.5% per year. PMID:15580846

Luketina, I A; Greig, L

2004-09-01

283

Linear output nitinol engine  

SciTech Connect

This patent describes a linear output nitinol engine consisting of a number of integrated communicating parts. The engine has an external support framework which is described in detail. The patent further describes a wire transport mechanism, a pair of linkage levers with a loom secured to them, a number of nitinol wires strung between the looms, and a power takeoff block secured to the linkage levers. A pulley positioned in a flip-flop supporting bracket and a power takeoff modality including a tension member connected to a power output cable in order to provide linear power output transmission is described. A method for biasing the timing and the mechanism for timing the synchronization of the throw over arms and the flip-flop of the pulley are also described.

Banks, R.M.

1986-01-14

284

Cardiac hybrid imaging.  

PubMed

Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. PMID:24658682

Gaemperli, Oliver; Kaufmann, Philipp A; Alkadhi, Hatem

2014-05-01

285

Cardiac Signatures of Personality  

PubMed Central

Background There are well-established relations between personality and the heart, as evidenced by associations between negative emotions on the one hand, and coronary heart disease or chronic heart failure on the other. However, there are substantial gaps in our knowledge about relations between the heart and personality in healthy individuals. Here, we investigated whether amplitude patterns of the electrocardiogram (ECG) correlate with neurotisicm, extraversion, agreeableness, warmth, positive emotion, and tender-mindedness as measured with the Neuroticism-Extraversion-Openness (NEO) personality inventory. Specifically, we investigated (a) whether a cardiac amplitude measure that was previously reported to be related to flattened affectivity (referred to as values) would explain variance of NEO scores, and (b) whether correlations can be found between NEO scores and amplitudes of the ECG. Methodology/Principal Findings NEO scores and rest ECGs were obtained from 425 healthy individuals. Neuroticism and positive emotion significantly differed between individuals with high and low values. In addition, stepwise cross-validated regressions indicated correlations between ECG amplitudes and (a) agreeableness, as well as (b) positive emotion. Conclusions/Significance These results are the first to demonstrate that ECG amplitude patterns provide information about the personality of an individual as measured with NEO personality scales and facets. These findings open new perspectives for a more efficient personality assessment using cardiac measures, as well as for more efficient risk-stratification and pre-clinical diagnosis of individuals at risk for cardiac, affective and psychosomatic disorders. PMID:22363649

Koelsch, Stefan; Enge, Juliane; Jentschke, Sebastian

2012-01-01

286

RESEARCH Open Access Plasma thioredoxin levels during post-cardiac  

E-print Network

RESEARCH Open Access Plasma thioredoxin levels during post-cardiac arrest syndrome: relationship, clinical demonstration of acute state of oxidative stress and inflammation during post-cardiac arrest TRX concentrations after cardiac arrest and assessed relationships with severity and outcome. Methods

Paris-Sud XI, Université de

287

In-hospital cardiac arrest leads to chronic memory impairment  

Microsoft Academic Search

Objective: To assess the prevalence and severity of memory deficits in a group of patients who survived an in-hospital cardiac arrest (IHCA) in comparison with patients resuscitated after cardiac arrest outside hospital (OHCA) and patients with acute myocardial infarction (MI). Subjects: Thirty-five IHCA survivors, 35 OHCA survivors, and 35 patients who had suffered MI uncomplicated by cardiac arrest. Procedure: Participants

Samantha M O'Reilly; Neil R Grubb; Ronan E O'Carroll

2003-01-01

288

In-hospital cardiac arrest leads to chronic memory impairment  

Microsoft Academic Search

Objective : To assess the prevalence and severity of memory deficits in a group of patients who survived an in-hospital cardiac arrest (IHCA) in comparison with patients resuscitated after cardiac arrest outside hospital (OHCA) and patients with acute myocardial infarction (MI). Subjects : Thirty-five IHCA survivors, 35 OHCA survivors, and 35 patients who had suffered MI uncomplicated by cardiac arrest.

Samantha M. O'Reilly; Neil R. Grubb; Ronan E. O'Carroll

2003-01-01

289

AN INTEGRATEDMICROELECTROMECHANICALRESONANT OUTPUT GYROSCOPE -  

E-print Network

AN INTEGRATEDMICROELECTROMECHANICALRESONANT OUTPUT GYROSCOPE - Ashwin A. Seshia*,Roger T. Howe vibratory rate gyroscope based on resonant sensing of the Coriolis force. The new design has several advantages over rate gyroscopes that utilize open-loop displacement sensing for rotation rate measurement

Tang, William C

290

Challenges in Predicting Power Output from Offshore Wind Farms  

E-print Network

Challenges in Predicting Power Output from Offshore Wind Farms R. J. Barthelmie1 and S. C. Pryor2 an offshore wind farm, accurate assessment of the wind resource/power output from the wind farm is a necessity. Accurately predicting the power output requires an estimate of the wind resource over the lifetime

Pryor, Sara C.

291

Off-patient assessment of pre-cordial impact mechanics among medical professionals in North-East Italy involved in emergency cardiac resuscitation.  

PubMed

Pre-cordial thump (PT) relies on cardiac mechano-electric transduction to transform mechanically-delivered energy into an electrophysiologically relevant stimulus. Its use for emergency resuscitation has declined recent years, amidst concerns about effectiveness and side-effects. In addition, there is insufficient knowledge about bio-mechanical properties and mechanisms of PT. Using a PT-mechanics recorder, we measured PT off-patient among healthcare professionals (n = 58) in North-East Italy, and related this to retrospective information on self-reported PT outcomes. Impact-speed and peak-force were 4.7 ± 1.3 m s?¹ (2.2-7.8 m s?¹) and 394 ± 110 N (202-648 N), respectively. Average self-reported cardioversion rate by PT was 35%. No adverse events were stated. All but 3 of PT providers with self-reported cardioversion rates ?50% had pre-impact fist-speeds of ?3.7 m s?¹. In comparison with previously-reported data from UK and US (n = 22 each), self-reported success-rates and pre-impact fist-speeds were more similar to US (PT-induced cardioversion rate 27.7%; fist-speed 4.17 ± 1.68 m s?¹) than to UK participants (PT-induced cardioversion rate 13.3%; fist-speed 1.55 ± 0.68 m s?¹). Small cohort-size, retrospective nature of data-gathering, and 'self-selection bias' (participants who have used PT on patients) limits the extent to which firm conclusions can be drawn. Observations are compatible, though, with the possibility that pre-impact fist-speed may affect success-rate of PT. Thus, where PT is used for acute resuscitation, it is delivered because it is immediately 'at hand'. Negative side effects are rare or absent in witnessed cardiac arrest cases. Pre-impact fist-speed may be a determinant of outcome, and this could be trained using devices suitable for self-assessment. PMID:22910435

Pellis, Tommaso; Pausler, Daniele; Gaiarin, Martina; Franceschino, Eliana; Epstein, Avi; Boulin, Christian; Kohl, Peter

2012-01-01

292

Origins of Cardiac Fibroblasts  

PubMed Central

Cardiac fibroblasts play a critical role in maintenance of normal cardiac function. They are indispensable for damage control and tissue remodeling on myocardial injury and principal mediators of pathological cardiac remodeling and fibrosis. Despite their manyfold functions, cardiac fibroblasts remain poorly characterized in molecular terms. Evidence is evolving that cardiac fibroblasts are a heterogeneous population and likely derive from various distinct tissue niches in health and disease. Here, we review our emerging understanding of where cardiac fibroblasts come from, as well as how we can possibly use this knowledge to develop novel therapies for cardiac fibrosis. PMID:21106947

Zeisberg, Elisabeth M.; Kalluri, Raghu

2011-01-01

293

An electricity-focused economic input-output model: Life-cycle assessment and policy implications of future electricity generation scenarios  

NASA Astrophysics Data System (ADS)

The electricity industry is extremely important to both our economy and our environment. We would like to be able to examine the economic, environmental and policy implications of both future electricity scenarios which include advanced generation technologies such as gasified coal, and of the products and processes which will use them, along with the interaction of this industry with the rest of the economy. This work builds upon an existing economic input-output framework, by adding detail about the electricity industry, specifically by differentiating among the various functions of the sector, and the different means of generating power. The mix of electricity consumed at any stage in the life-cycle of a product, process or industrial sector has a significant effect on the associated inventory of emissions. Fossil fuel or nuclear generators, large-scale hydroelectric, and renewable options such as geothermal, wind and solar each have a unique set of issues---both in the production of electricity at the plant and throughout the supply chain. Decision makers need better information regarding the environmental and economic impact of the electricity industry, including full supply chain details---the interaction of the electricity industry with the other 500 sectors of the economy. A systematic method for creating updated state level and sector generation mixes is developed. The results show that most sector mixes are very close to the U.S. average due to geographic dispersion of industries, but that some sectors are different, and they tend to be important raw material extraction or primary manufacturing industries. We then build a flexible framework for creating new sectors, supply chains and emission factors for the generation, transmission and distribution portions of the electricity industry. We look at scenarios of the present and future, for electricity and for particular products, and develop results which show environmental impacts split up by generation type, and with full supply chain detail. For analyses of the current electricity system and products, economic and environmental results match well with external verification sources, but for analyses of the future, there is significant uncertainty.

Marriott, Joe

294

The endogenous peptide apelin potently improves cardiac contractility and reduces cardiac loading in vivo  

Microsoft Academic Search

Objective: The endogenous peptide apelin is differentially regulated in cardiovascular disease but the nature of its role in cardiac function remains unclear. Methods: We investigated the functional relevance of this peptide using ECG and respiration gated magnetic resonance imaging, conductance catheter pressure-volume hemodynamic measurements, and echocardiography in vivo. In addition, we carried out histology and immunohistochemistry to assess cardiac hypertrophy

Euan A. Ashley; Jennifer Powers; Mary Chen; Ramendra Kundu; Tom Finsterbach; Anthony Caffarelli; Alicia Deng; Jens Eichhorn; Raina Mahajan; Rani Agrawal; Joan Greve; Robert Robbins; Andrew J. Patterson; Daniel Bernstein; Thomas Quertermous

295

The effect of garden designs on mood and heart output in older adults residing in an assisted living facility.  

PubMed

Objective: The objective of this study is to trace short-term changes in mood and heart function in elderly individuals in response to exposure to different landscaped spaces.Background: Nineteen elderly but cognitively intact residents of an assisted living facility participated in the study. They were exposed to three landscaped spaces: a Japanese style garden, an herb garden, and a simple landscaped area planted with a single tree.Methods: To assess the effect of different landscaped spaces on older adults, individuals were monitored for mood and cardiac function in response to short exposures to spaces. Mood state was assessed using Profile of Mood States (POMS) before and after viewing the spaces. Cardiac output was assessed using a portable electrocardiograph monitor before and during the viewing.Results: We found that the structured gardens evoked greater responses in all outcome measures. Scores on the POMS improved after observation of the two organized gardens compared to responses to the simple landscaped space with a single tree. During the observation period, heart rate was significantly lower in the Japanese garden than in the other environments, and sympathetic function was significantly lower as well.Conclusions: We conclude that exposure to organized gardens can affect both the mood and cardiac physiology of elderly individuals. Our data further suggest that these effects can differ depending on the types of landscape to which an individual is exposed.Keywords: Elderly, Japanese garden, herb garden, heart rate, mood, healing environmentPreferred Citation: Goto, S., Park, B-J., Tsunetsugu, Y., Herrup, K., & Miyazaki, Y. (2013). The effect of garden designs on mood and heart output in older adults residing in an assisted living facility. Health Environments Research & Design Journal 6(2), pp 27-42. PMID:23532694

Goto, Seiko; Park, Bum-Jin; Tsunetsugu, Yuko; Herrup, Karl; Miyazaki, Yoshifumi

2013-01-01

296

CARDIAC MUSCLE  

PubMed Central

With light and electron microscopy a comparison has been made of the morphology of ventricular (V) and Purkinje (P) fibers of the hearts of guinea pig, rabbit, cat, dog, goat, and sheep. The criteria, previously established for the rabbit heart, that V fibers are distinguished from P fibers by the respective presence and absence of transverse tubules is shown to be true for all animals studied. No evidence was found of a permanent connection between the sarcoplasmic reticulum and the extracellular space. The sarcoplasmic reticulum (SR) of V fibers formed couplings with the sarcolemma of a transverse tubule (interior coupling) and with the peripheral sarcolemma (peripheral coupling), whereas in P fibers the SR formed only peripheral couplings. The forms of the couplings were identical. The significance, with respect to excitation-contraction coupling, of the difference in the form of the couplings in cardiac versus skeletal muscle is discussed together with the electrophysiological implications of the differing geometries of bundles of P fibers from different animals. PMID:5645545

Sommer, Joachim R.; Johnson, Edward A.

1968-01-01

297

The China PEACE (Patient-centered Evaluative Assessment of Cardiac Events) Retrospective Study of Acute Myocardial Infarction: Study Design China PEACE-Retrospective AMI Study Design  

PubMed Central

Background Cardiovascular diseases are rising as a cause of death and disability in China. To improve outcomes for patients with these conditions, the Chinese government, academic researchers, clinicians, and more than 200 hospitals have created China Patient-centered Evaluative Assessment of Cardiac Events (China-PEACE), a national network for research and performance improvement. The first study from China PEACE, the Retrospective Study of Acute Myocardial Infarction (China PEACE-Retrospective AMI Study), is designed to promote improvements in AMI quality of care by generating knowledge about the characteristics, treatments, and outcomes of patients hospitalized with acute myocardial infarction (AMI) across a representative sample of Chinese hospitals over the last decade. Methods and Results The China PEACE-Retrospective AMI Study will examine more than 18,000 patient records from 162 hospitals identified using a 2-stage cluster sampling design within economic-geographic regions. Records were chosen from 2001, 2006, and 2011 to identify temporal trends. Data quality will be monitored by a central coordinating center and will, in particular, address case ascertainment, data abstraction, and data management. Analyses will examine patient characteristics, diagnostic testing patterns, in-hospital treatments, in-hospital outcomes, and variation in results by time and site of care. In addition to publications, data will be shared with participating hospitals and the Chinese government to develop strategies to promote quality improvement. Conclusions The China PEACE-Retrospective AMI Study is the first to leverage the China PEACE platform to better understand AMI across representative sites of care and over the last decade in China. The China PEACE collaboration between government, academicians, clinicians and hospitals is poised to translate research about trends and patterns of AMI practices and outcomes into improved care for patients. PMID:24221838

Dharmarajan, Kumar; Li, Jing; Li, Xi; Lin, Zhenqiu; Krumholz, Harlan; Jiang, Lixin

2014-01-01

298

Cardiac Mechanics Evaluated by Speckle Tracking Echocardiography  

PubMed Central

Natural myocardial markers, or speckles, originated from constructive and destructive interference of ultrasound in the tissues may provide early diagnosis of myocardial changes and be used in the prediction of some cardiac events. Due to its relatively temporal stability, speckles can be tracked by dedicated software along the cardiac cycle, enabling the analysis of the systolic and diastolic function. They are identified by either conventional 2D grey scale and by 3D echo, conferring independence of the insonation angle, thus allowing assessment of cardiac mechanics in the three spatial planes: longitudinal, circumferential, and radial. The purposes of the present paper are: to discuss the role and the meaning of cardiac strain obtained by speckle tracking during the evaluation of cardiac physiology and to discuss clinical applications of this novel echocardiographic technology. PMID:24844877

Abduch, Maria Cristina Donadio; Alencar, Adriano Mesquita; Mathias, Wilson; Vieira, Marcelo Luiz de Campos

2014-01-01

299

A methodology for fast assessments to the electrical activity of barrel fields in vivo: from population inputs to single unit outputs  

PubMed Central

Here we propose a methodology to analyze volumetric electrical activity of neuronal masses in the somatosensory barrel field of Wistar rats. The key elements of the proposed methodology are a three-dimensional microelectrode array, which was customized by our group to observe extracellular recordings from an extended area of the barrel field, and a novel method for the current source density analysis. By means of this methodology, we were able to localize single barrels from their event-related responses to single whisker deflection. It was also possible to assess the spatiotemporal dynamics of neuronal aggregates in several barrels at the same time with the resolution of single neurons. We used simulations to study the robustness of our methodology to unavoidable physiological noise and electrode configuration. We compared the accuracy to reconstruct neocortical current sources with that obtained with a previous method. This constitutes a type of electrophysiological microscopy with high spatial and temporal resolution, which could change the way we analyze the activity of cortical neurons in the future. PMID:24550785

Riera, Jorge J.; Goto, Takakuni; Kawashima, Ryuta

2014-01-01

300

Cardiac MRI and Iron Overload Cardiomyopathy in Thalassemia Major: A Case Report  

PubMed Central

Introduction: Heart failure is the leading cause of death in patients with Thalassemia major and primarily results from transfusional iron overload. It is essential to assess myocardial iron load. Previous studies have shown that neither serum ferritin nor liver iron concentration gives a reliable measure of cardiac iron accumulation. Cardiac T2* MRI technique offers noninvasive measurement of myocardial iron load. Case Report: A 39-year-old man with a past medical history significant for beta thalassemia major requiring blood transfusions every three-weeks and on iron chelation, presented with a cough, high fevers, and chills. He was subsequently found to have community acquired pneumonia and was treated with ceftriaxone and doxycycline. His hospital course was significant for episodes of atrial fibrillation and non-sustained ventricular tachycardia. An echocardiogram showed normal left ventricular function with an ejection fraction of 70%, which hadn't changed from 2011. Although, the patient didn't have symptoms of heart failure, he likely had ventricular dysfunction that could be masked by the basal high cardiac output which can be seen in patients with chronic anemia and we decided to start the patient on sotalol 80 mg twice a day. The MRI software for multiecho T2* measurement was installed at Queens Medical Center in September 2011 and we were able to obtain images for our patient at that time. His myocardial T2* value was estimated to be 9 milliseconds which suggests an increased risk for the development of future cardiac arrhythmias and heart failure. The repeat cardiac MRI images after discharge showed 8 milliseconds which suggested an interval worsening of the iron deposition within the myocardium. Discussion: We were able to keep track of the progression of his iron cardiomyopathy, and start additional treatment. The patient continues to be followed by a hematologist for management of his hemochromatosis and a cardiologist for his infiltrative heart disease both resulting from his need for chronic blood transfusions. In patients with iron overload cardiomyopathy, their systolic function is preserved until a very late stage as iron deposition begins within the epicardium and extends to the myocardium. This case illustrates the importance of assessing cardiac iron content utilizing cardiac MRI as it is less invasive than cardiac biopsy and may show earlier involvement than echocardiogram.

Azuma, Steven

2014-01-01

301

Assessment of diastolic function with Doppler tissue imaging after cardiac surgery: effect of the "postoperative septum" in on-pump and off-pump procedures.  

PubMed

Doppler tissue imaging (DTI) of mitral annular velocity is useful in assessing diastolic function. Most centers record at the septal or lateral segments of the annulus. Cardiopulmonary bypass produces changes in the motion of the interventricular septum. We evaluated the use of DTI after operation with and without cardiopulmonary bypass. 18 patients scheduled for cardiac surgery were prospectively examined. Nine underwent cardiopulmonary bypass. Nine had operation without bypass. DTI was performed 4 +/- 3 days before operation and again 31+/- 7 days afterwards. Early diastolic velocities of the lateral and septal segments of the mitral annulus were measured. Ejection fraction and transmitral diastolic early-to-late filling (E/A) ratios were also assessed. Early diastolic septal mitral annular velocity decreased (7.9 +/- 1.2 to 5.9 +/- 1.1 cm/s [P= .001]) after on-pump operation whereas lateral segment velocity remained unchanged (8.5 +/- 2.9 to 8.2 +/- 3.7 cm/s [P = .30]). E/A ratio did not change after operation (1.28 +/- 0.25 to 1.21 +/- 0.47 [P = .45]). In contrast, septal segment velocity in the off-pump group trended higher after operation (5.3 +/- 1.9 to 6.0 +/- 1.5 cm/s [P = .20]). Lateral segment velocity and E/A ratio also increased somewhat, but changes were not significant (6.2 +/- 1.7 to 6.7 +/- 2.9 cm/s [P = .15] and 1.1 +/- 0.5 to 1.2 +/- 0.4 [P = .13], respectively). Ejection fraction increased in both groups. Early diastolic velocity of the septal mitral annulus decreases after operation with cardiopulmonary bypass, but does not change after off-pump operation. In contrast, early diastolic velocity of the lateral segment is not affected by either on-pump or off-pump operation. Measuring lateral segment velocity is recommended for diastolic DTI after cardiopulmonary bypass, as septal DTI may incorrectly suggest diastolic dysfunction. PMID:16581488

Malouf, Philip J; Madani, Michael; Gurudevan, Swaminatha; Waltman, Thomas J; Raisinghani, Ajit B; DeMaria, Anthony N; Blanchard, Daniel G

2006-04-01

302

Nitric Oxide Synthase Inhibition Attenuates Cardiac Response to Hemodilution with Viscogenic Plasma Expander  

PubMed Central

Background and Objectives Increased vascular wall shear stress by elevated plasma viscosity significantly enhances the endothelial nitric oxide synthase (eNOS) activity during an acute isovolemic hemodilution. Also the modulation of plasma viscosity has effects on the cardiac function that were revealed if a left ventricular (LV) pressure-volume (PV) measurement was used. The aim of this study was to assess cardiac function responses to nitric oxide synthase (NOS) inhibitors with the presence of an elevated plasma viscosity but a low hematocrit level. Furthermore, systemic parameters were monitored in a murine model. Materials and Methods As test group five anesthetized hamsters were administered with N(G)-nitro-L-arginine methyl ester (L-NAME), NOS inhibitor, whereas five other hamsters were used as control group without L-NAME infusion. The dosage of L-NAME was 10 mg/kg. An isovolemic hemodilution was performed by 40% of estimated blood volume with 6% w/v dextran 2000 kDa, high viscosity plasma expanders (PEs) with viscosity 6.34 cP. LV function was measured and assessed using a 1.4 Fr PV conductance catheter. Results The study results demonstrated that NOS inhibition prevented the normal cardiac adaptive response after hemodilution. The endsystolic pressure increased 14% after L-NAME infusion and maintained higher than at the baseline after hemodilution, whereas it gradually decreased in the animals without L-NAME infusion. The admission of L-NAME significantly decreased the maximum rate of ventricular pressure rise (+dP/dtmax), stroke volume and cardiac output after hemodilution if compared to the control group (p<0.05). Conclusion This finding supports the presumption that nitric oxide induced by an increased plasma viscosity with the use of a high viscosity PE plays a major role in the cardiac function during an acute isovolemic hemodilution. PMID:24653740

Cabrales, Pedro

2014-01-01

303

Cardiac Syndrome X  

MedlinePLUS

Related terms: angina, microvascular angina Cardiac syndrome X patients have the pain of angina , but they do not have coronary artery disease ( CAD ). So even though patients with cardiac syndrome X ...

304

Effects of Prior Intensive Versus Conventional Therapy and History of Glycemia on Cardiac Function in Type 1 Diabetes in the DCCT/EDIC  

PubMed Central

Intensive diabetes therapy reduces the prevalence of coronary calcification and progression of atherosclerosis and the risk of cardiovascular disease (CVD) events in the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study. The effects of intensive therapy on measures of cardiac function and structure and their association with glycemia have not been explored in type 1 diabetes (T1DM). We assess whether intensive treatment compared with conventional treatment during the DCCT led to differences in these parameters during EDIC. After 6.5 years of intensive versus conventional therapy in the DCCT, and 15 years of additional follow-up in EDIC, left ventricular (LV) indices were measured by cardiac magnetic resonance (CMR) imaging in 1,017 of the 1,371 members of the DCCT cohort. There were no differences between the DCCT intensive versus conventional treatment in end diastolic volume (EDV), end systolic volume, stroke volume (SV), cardiac output (CO), LV mass, ejection fraction, LV mass/EDV, or aortic distensibility (AD). Mean DCCT/EDIC HbA1c over time was associated with EDV, SV, CO, LV mass, LV mass/EDV, and AD. These associations persisted after adjustment for CVD risk factors. Cardiac function and remodeling in T1DM assessed by CMR in the EDIC cohort was associated with prior glycemic exposure, but there was no effect of intensive versus conventional treatment during the DCCT on cardiac parameters. PMID:23520132

Genuth, Saul M.; Backlund, Jye-Yu C.; Bayless, Margaret; Bluemke, David A.; Cleary, Patricia A.; Crandall, Jill; Lachin, John M.; Lima, Joao A.C.; Miao, Culian; Turkbey, Evrim B.

2013-01-01

305

An integrated bioimpedance—ECG gating technique for respiratory and cardiac motion compensation in cardiac PET  

NASA Astrophysics Data System (ADS)

Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6? ± ?3.3?mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4?ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3? ± ?1.3?mm) compared to cardiac-gated images (11.3? ± ?1.3?mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes.

Koivumäki, Tuomas; Nekolla, Stephan G.; Fürst, Sebastian; Loher, Simone; Vauhkonen, Marko; Schwaiger, Markus; Hakulinen, Mikko A.

2014-10-01

306

An integrated bioimpedance-ECG gating technique for respiratory and cardiac motion compensation in cardiac PET.  

PubMed

Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6? ± ?3.3?mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4?ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3? ± ?1.3?mm) compared to cardiac-gated images (11.3? ± ?1.3?mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes. PMID:25295531

Koivumäki, Tuomas; Nekolla, Stephan G; Fürst, Sebastian; Loher, Simone; Vauhkonen, Marko; Schwaiger, Markus; Hakulinen, Mikko A

2014-10-01

307

Relationship between cardiac function and resting cerebral blood flow: MRI measurements in healthy elderly subjects.  

PubMed

Although both impaired cardiac function and reduced cerebral blood flow are associated with ageing, current knowledge of the influence of cardiac function on resting cerebral blood flow (CBF) is limited. The aim of this study was to investigate the potential effects of cardiac function on CBF. CBF and cardiac output were measured in 31 healthy subjects 50-75 years old using magnetic resonance imaging techniques. Mean values of CBF, cardiac output and cardiac index were 43·6 ml per 100 g min(-1) , 5·5 l min(-1) and 2·7 l min(-1)  m(-2) , respectively, in males, and 53·4 ml per 100 g min(-1) , 4·3 l min(-1) and 2·4 l min(-1) m(-2) , respectively, in females. No effects of cardiac output or cardiac index on CBF or structural signs of brain ageing were observed. However, fractional brain flow defined as the ratio of total brain flow to cardiac output was inversely correlated with cardiac index (r(2)  = 0·22, P = 0·008) and furthermore lower in males than in females (8·6% versus 12·5%, P = 0·003). Fractional brain flow was also inversely correlated with cerebral white matter lesion grade, although this effect was not significant when adjusted for age. Frequency analysis of heart rate variability showed a gender-related inverse association of increased low-to-high-frequency power ratio with CBF and fractional brain flow. The findings do not support a direct effect of cardiac function on CBF, but demonstrates gender-related differences in cardiac output distribution. We propose fractional brain flow as a novel index that may be a useful marker of adequate brain perfusion in the context of ageing as well as cardiovascular disease. PMID:24314236

Henriksen, Otto M; Jensen, Lars T; Krabbe, Katja; Larsson, Henrik B W; Rostrup, Egill

2014-11-01

308

The relationships between self-assessed habitual physical activity and non-invasive measures of cardiac autonomic modulation in young healthy volunteers  

Microsoft Academic Search

Heart rate variability estimates cardiac autonomic modulation, but the relationship between habitual physical activity and heart rate variability remains unclear. The aims of this study were to compare RR-interval and heart rate variability indices in individuals of different habitual physical activity levels, and examine the relationship between habitual physical activity and heart rate variability. Ninety-two healthy volunteers (47 men, 45

Gavin R. H. Sandercock; Darren Hardy-Shepherd; David Nunan; David Brodie

2008-01-01

309

Cardiac Disease in Pregnancy: Value of Echocardiography  

Microsoft Academic Search

Cardiovascular disease in women during pregnancy poses particular challenges. It continues to be a leading cause of maternal\\u000a mortality and contributes to significant morbidity. Echocardiography is essential in characterizing the extent and effects\\u000a of heart disease prior to, during, and after pregnancy. By understanding the physiologic adaptation in pregnancy with increases\\u000a in heart rate, blood volume, and cardiac output, and

Sarah Tsiaras; Athena Poppas

2010-01-01

310

Cardiomyocyte-restricted inhibition of G protein-coupled receptor kinase-3 attenuates cardiac dysfunction after chronic pressure overload.  

PubMed

Transgenic mice with cardiac-specific expression of a peptide inhibitor of G protein-coupled receptor kinase (GRK)3 [transgenic COOH-terminal GRK3 (GRK3ct) mice] display myocardial hypercontractility without hypertrophy and enhanced ?(1)-adrenergic receptor signaling. A role for GRK3 in the pathogenesis of heart failure (HF) has not been investigated, but inhibition of its isozyme, GRK2, has been beneficial in several HF models. Here, we tested whether inhibition of GRK3 modulated evolving cardiac hypertrophy and dysfunction after pressure overload. Weight-matched male GRK3ct transgenic and nontransgenic littermate control (NLC) mice subjected to chronic pressure overload by abdominal aortic banding (AB) were compared with sham-operated (SH) mice. At 6 wk after AB, a significant increase of cardiac mass consistent with induction of hypertrophy was found, but no differences between GRK3ct-AB and NLC-AB mice were discerned. Simultaneous left ventricular (LV) pressure-volume analysis of electrically paced, ex vivo perfused working hearts revealed substantially reduced systolic and diastolic function in NLC-AB mice (n = 7), which was completely preserved in GRK3ct-AB mice (n = 7). An additional cohort was subjected to in vivo cardiac catheterization and LV pressure-volume analysis at 12 wk after AB. NLC-AB mice (n = 11) displayed elevated end-diastolic pressure (8.5 ± 3.1 vs. 2.9 ± 1.2 mmHg, P < 0.05), reduced cardiac output (3,448 ± 323 vs. 4,488 ± 342 ?l/min, P < 0.05), and reduced dP/dt(max) and dP/dt(min) (both P < 0.05) compared with GRK3ct-AB mice (n = 16), corroborating the preserved cardiac structure and function observed in GRK3ct-AB hearts assessed ex vivo. Increased cardiac mass and myocardial mRNA expression of ?-myosin heavy chain confirmed the similar induction of cardiac hypertrophy in both AB groups, but only NLC-AB hearts displayed significantly elevated mRNA levels of brain natriuretic peptide and myocardial collagen contents as well as reduced ?(1)-adrenergic receptor responsiveness to isoproterenol, indicating increased LV wall stress and the transition to HF. Inhibition of cardiac GRK3 in mice does not alter the hypertrophic response but attenuates cardiac dysfunction and HF after chronic pressure overload. PMID:22542621

von Lueder, Thomas G; Gravning, Jørgen; How, Ole-Jakob; Vinge, Leif E; Ahmed, Mohammed Shakil; Krobert, Kurt A; Levy, Finn Olav; Larsen, Terje S; Smiseth, Otto A; Aasum, Ellen; Attramadal, Håvard

2012-07-01

311

Cardiac electrophysiology in mice: a matter of size  

PubMed Central

Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias. PMID:22973235

Kaese, Sven; Verheule, Sander

2012-01-01

312

[Malignant cardiac tumors].  

PubMed

Cardiac neoplasms are a rare occurrence in clinical practice. The various frequencies of primary and secondary malignant tumors vary from report to report, approximately 1% in most autopsy series and 4% in cancer patient's autopsies. Cardiac malignancies account for less 1% of cardiac surgery and about for 0.1% of cardiac echographic studies. The presence of metastatic tumor to the heart usually indicates widespread metastases. Lung carcinomas are the most commonly encountered tumor followed by breast and pancreas cancer and melanoma. Apart from primary pericardial mesothelioma, primary cardiac tumors are high-grade sarcomas with a high metastatic potency that often becomes evident early after surgery. Symptoms are non specific, occur late in the disease and affect few patients; especially secondary neoplasms of the heart take their course so fast that they cannot become symptomatic. The signs of cardiac neoplasms are divided into systemic symptoms (fever, arthralgias and myalgias), cardiac symptoms (congestive heart failure, arrhythmia, chest pain) and uncommon embolisms. Diagnosis is actually made easier with cardiac echography. Cardiac RMI is helpful to estimate vessels and pericardium involvement. Due to its poor prognosis, treatment of cardiac metastases is restricted to best supportive care. For primary cardiac neoplasms, surgery must be carefully discussed because operative intervention is often followed by rapid widespread metastases that adjuvant chemotherapy cannot avoid in most cases. PMID:15899620

Debourdeau, Philippe; Gligorov, Joseph; Teixeira, Luis; Aletti, Marc; Zammit, Christine

2004-11-01

313

Assessment of the early stage of cardiac remodeling of spontaneously hypertensive heart failure rats using the quantitative 3-dimensional analysis provided by acipimox-enhanced FDG-PET.  

PubMed

Spontaneously hypertensive heart failure rats (SHHF) appear to constitute an original model for analyzing the evolution of the metabolic syndrome towards heart failure. This study aimed to characterize early cardiac dysfunction and remodeling in SHHF rats: (1) as compared with spontaneously hypertensive rats (SHR) and with a control group of Kyoto rats (WKY), and (2) by using the 3-dimensional quantitative analysis provided by acipimox-enhanced positron emission tomography (PET) with (18)F-fluorodesoxyglucose (FDG). Left ventricular (LV) ejection fraction (EF) and volume were quantified by automatic software on the FDG-PET images recorded in SHR (n = 20), SHHF (n = 18) and WKY-rats (n = 19) at ages 3 or 10 months old. Arterial blood pressure was determined by cardiac catheterization and cardiac fibrosis was quantified after sacrifice. Blood pressure was similarly elevated in SHR and SHHF rats (respective systolic blood pressures at 10-months: 199 ± 39 vs. 205 ± 2 mmHg), but SHHF rats had higher body mass than SHR rats (at 10-months, 630 ± 36 vs. 413 ± 27 g, p < 0.05) and higher blood levels of cholesterol and of triglycerides. At 3 months, cardiac parameters did not show significant differences between groups but at 10-months, SHHF and SHR rats exhibited an enhancement in myocardial mass and fibrosis associated with a clear decline in LV-EF (SHHF: 46 ± 6 %; SHR: 47 ± 5 %) as compared with WKY (56 ± 6 %, p < 0.01 for both comparisons). Cardiac remodeling of SHHF rats was clearly observable by FDG-PET from the age of 10-months, but in a similar way to that observed for SHR rats, suggesting a predominant role of hypertension. PMID:24384858

Maskali, Fatiha; Poussier, Sylvain; Louis, Huguette; Boutley, Henri; Lhuillier, Mickael; Thornton, Simon N; Karcher, Gilles; Lacolley, Patrick; Marie, Pierre Y

2014-02-01

314

Antioxidant treatment improves neonatal survival and prevents impaired cardiac function at adulthood following neonatal glucocorticoid therapy  

PubMed Central

Glucocorticoids are widely used to treat chronic lung disease in premature infants but their longer-term adverse effects on the cardiovascular system raise concerns. We reported that neonatal dexamethasone treatment in rats induced in the short term molecular indices of cardiac oxidative stress and cardiovascular tissue remodelling at weaning, and that neonatal combined antioxidant and dexamethasone treatment was protective at this time. In this study, we investigated whether such effects of neonatal dexamethasone have adverse consequences for NO bioavailability and cardiovascular function at adulthood, and whether neonatal combined antioxidant and dexamethasone treatment is protective in the adult. Newborn rat pups received daily i.p. injections of a human-relevant tapering dose of dexamethasone (D; n= 8; 0.5, 0.3, 0.1 ?g g?1) or D with vitamins C and E (DCE; n= 8; 200 and 100 mg kg?1, respectively) on postnatal days 1–3 (P1–3); vitamins were continued from P4 to P6. Controls received equal volumes of vehicle from P1 to P6 (C; n= 8). A fourth group received vitamins alone (CCE; n= 8). At P100, plasma NO metabolites (NOx) was measured and isolated hearts were assessed under both Working and Langendorff preparations. Relative to controls, neonatal dexamethasone therapy increased mortality by 18% (P < 0.05). Surviving D pups at adulthood had lower plasma NOx concentrations (10.6 ± 0.8 vs. 28.0 ± 1.5 ?m), an increased relative left ventricular (LV) mass (70 ± 2 vs. 63 ± 1%), enhanced LV end-diastolic pressure (14 ± 2 vs. 8 ± 1 mmHg) and these hearts failed to adapt output with increased preload (?cardiac output: 2.9 ± 2.0 vs. 10.6 ± 1.2 ml min?1) or afterload (?cardiac output: ?5.3 ± 2.0 vs.1.4 ± 1.2 ml min?1); all P < 0.05. Combined neonatal dexamethasone with antioxidant vitamins improved postnatal survival, restored plasma NOx and protected against cardiac dysfunction at adulthood. In conclusion, neonatal dexamethasone therapy promotes cardiac dysfunction at adulthood. Combined neonatal treatment with antioxidant vitamins is an effective intervention. PMID:23940378

Niu, Youguo; Herrera, Emilio A; Evans, Rhys D; Giussani, Dino A

2013-01-01

315

Body size and work output.  

PubMed

The relationship between work output and anthropometric, biochemical, and socioeconomic varables was studied in 57 male industrial workers engaged in the production of detonator fuses. These workers were studied for 3 months and their daily work output was carefully measured. Work output was measured in terms of the number of fuses produced per day. Clinical and biochemical examination indicated that their current nutritional status was adequate. Among the parameters studied only body weight, height, and lean body weight were significantly correlated with work output. Body weight and lean body weight were significantly correlated (P less than 0.001) with work output even after removing the influence of height by partial correlation. Total daily work output was significantly higher (P less than 0.01) in those with higher body weight and lean body weight. The rate of work was also higher in the higher body weight group PMID:842484

Satyanarayana, K; Naidu, A N; Chatterjee, B; Rao, N

1977-03-01

316

Serial Input Output  

SciTech Connect

Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each stream, record or block name must be unique in its category (i.e. all streams must have different names, but a stream can have the same name as a record). Each category is an arbitrary length list which is handled by a 'manager' and there is one manager for each category.

Waite, Anthony; /SLAC

2011-09-07

317

Central Venous Saturation: A Prognostic Tool in Cardiac Surgery patients  

Microsoft Academic Search

Background: Central venous oxygen saturation (ScvO2) is a valuable prognostic marker in sepsis. However, its value in cardiac surgery has not been assessed yet. This study aimed at evaluating ScvO2 as a tool for predicting short-term organ dysfunction (OD) after cardiac surgery. Methods: A prospective cohort including cardiac surgery patients submitted to a goal-oriented therapy to maintain ScvO2 above 70%

Pedro M. Nogueira; Hugo T. Mendonça-Filho; Luiz Antonio Campos; Renato V. Gomes; Alexandre R. Felipe; Marco A. Fernandes; Cristiane A. Villela-Nogueira; José R. Rocco

2010-01-01

318

Utility of Cardiac Magnetic Resonance to assess association between admission hyperglycemia and myocardial damage in patients with reperfused ST-Segment Elevation Myocardial Infarction  

Microsoft Academic Search

AIMS: to investigate the association between admission hyperglycemia and myocardial damage in patients with ST-segment elevation myocardial infarction (STEMI) using Cardiac Magnetic Resonance (CMR). METHODS: We analyzed 113 patients with STEMI treated with successful primary percutaneous coronary intervention. Admission hyperglycemia was defined as a glucose level ? 7.8 mmol\\/l. Contrast-enhanced CMR was performed between 3 and 7 days after reperfusion

Alexandre Cochet; Marianne Zeller; Alain Lalande; Isabelle L'Huillier; Paul M Walker; Claude Touzery; Bruno Verges; Jean-Eric Wolf; François Brunotte; Yves Cottin

2008-01-01

319

Assessment of acute myocardial infarction: current status and recommendations from the North American society for cardiovascular imaging and the European society of cardiac radiology  

Microsoft Academic Search

There are a number of imaging tests that are used in the setting of acute myocardial infarction and acute coronary syndrome.\\u000a Each has their strengths and limitations. Experts from the European Society of Cardiac Radiology and the North American Society\\u000a for Cardiovascular Imaging together with other prominent imagers reviewed the literature. It is clear that there is a definite\\u000a role

Arthur E. Stillman; Matthijs Oudkerk; David Bluemke; Jens Bremerich; Fabio P. Esteves; Ernest V. Garcia; Matthias Gutberlet; W. Gregory Hundley; Michael Jerosch-Herold; Dirkjan Kuijpers; Raymond K. Kwong; Eike Nagel; Stamatios Lerakis; John Oshinski; Jean-François Paul; Richard Underwood; Bernd J. Wintersperger; Michael R. Rees

2011-01-01

320

Veterinary and toxicological applications for the detection of cardiac injury using cardiac troponin.  

PubMed

The use of cardiac troponin (cTn), the 'gold-standard' biomarker of myocardial injury in humans, is growing in veterinary medicine and in animal safety studies, although there are differences in its application in animals. In this study six new assays for the marker were assessed in 619 animals of six different species (dog, cat, horse, cattle, rat and rabbit), in clinical and drug-safety studies. Healthy animals and clinical cases without cardiac disease served as controls. Several of the tested assays had poor analytic or diagnostic sensitivity and only one test was effective in all species and in all models of cardiac injury. This assay had the highest sensitivity and widest dynamic range, and identified cardiac injury due to anaemia, pancreatitis, uncontrolled Addison's and Cushing's disease, old age, renal disease, severe colic, lymphoma and neoplasia. Detection of the cTnI and cTnT forms correlated with loss of cardiac function in toxicity studies in rodents and rabbit. Increased serum cTnI was not found to correlate with disease aetiology or pathogenesis, but was effective in detecting, monitoring and quantifying ongoing cardiac injury. Cardiac injury, as demonstrated by elevated cTnI in blood, appears to be a common sequel to a wide variety of both primarily cardiac disease and of other diseases that do not primarily involve the cardiovascular system. PMID:20621713

Serra, Mariana; Papakonstantinou, Stratos; Adamcova, Michaela; O'Brien, Peter James

2010-07-01

321

Emergency cardiac support with extracorporeal membrane oxygenation for cardiac arrest.  

PubMed

A 46-year-old woman with no major medical history presented to the emergency department with chest pain and evidence of anterior, anterolateral, and inferior ST-elevation myocardial infarction. Her condition quickly deteriorated into cardiogenic shock with ventricular arrhythmia. Despite revascularization of the left anterior descending artery and intravenous inotrope and antiarrhythmic therapy, her unstable hemodynamics and arrhythmias persisted. Early emergency initiation of venoarterial extracorporeal membrane oxygenation (ECMO) led to prompt hemodynamic and rhythm stability; however, adequate endogenous cardiac output did not ensue, and she was not able to be weaned from ECMO until hospital day 8. She subsequently recovered and continues to do well in the outpatient setting. This case demonstrates the remarkable hemodynamic and rhythm stability that early initiation of ECMO can provide in the setting of unstable myocardial infarction. PMID:23809321

Tweet, Marysia S; Schears, Gregory J; Cassar, Andrew; Sheldon, Seth H; McGlinch, Brian P; Sandhu, Gurpreet S

2013-07-01

322

New output improvements for CLASSY  

NASA Technical Reports Server (NTRS)

Additional output data and formats for the CLASSY clustering algorithm were developed. Four such aids to the CLASSY user are described. These are: (1) statistical measures; (2) special map types; (3) formats for standard output; and (4) special cluster display method.

Rassbach, M. E. (principal investigator)

1981-01-01

323

Psychological adjustment after cardiac transplantation.  

PubMed

Cardiac transplantation is viable therapeutic alternative for patients with end-stage heart disease, which offers a favourable short- and medium-term prognosis. The survival has improved from 20% of patients who survived at one year after transplantation in the 1960s to the present figures of 80%-85% of patients who are alive at one year, and 50%-70% of patients who are alive at five years, after transplantation. Therefore, it seems timely to focus attention on the psychological well-being of cardiac-transplant recipients. The medical literature is scant in regard to the psychiatric and the psychosocial impact of cardiac transplantation on recipients, and a systematic and prospective study of the psychosocial adaptation of recipients is lacking. Since 1984, we have been studying the emotional impact of cardiac transplantation on recipients and their families. This article presents the results for a group of recipients who have been assessed before transplantation, then followed-up at discharge from hospital and at four, eight and 12 months after transplantation. The study attempted to quantitate the recipients' anxiety, depression, body image and subjective quality of life by way of standardized self-assessment questionnaires. The recipients' satisfaction with relationships or their marital situation also was reported, as were their degree of rehabilitation at 12 months and their attitudes to various aspects of treatment after the transplantation. Before the transplantation, 53% of patients reported an increase in anxiety and 34% of patients recorded scores that indicated mild-to-moderate levels of depression. Thirty-seven per cent of patients showed a deterioration in the quality of their lives and 34% of patients had a negative body image. After the transplantation, significant improvements occurred in all parameters, which were maintained at follow-up. PMID:3041251

Jones, B M; Chang, V P; Esmore, D; Spratt, P; Shanahan, M X; Farnsworth, A E; Keogh, A; Downs, K

1988-08-01

324

Motor vehicle output and GDP, 1968-2007.  

SciTech Connect

In this paper, we assess the performance of the BEA series 'value of motor vehicle output' as an indicator of the business cycle over the period 1968-2007. We statistically assess the causal relationship between real motor vehicle output (RMVO) and real gross domestic product (RGDP). This is accomplished by standard estimation and statistical methods used to assess vector autoregressive models. This assessment represents the initial results of a more encompassing research project, the intent of which is to determine the dynamic interaction of the transport sector with the overall economy. It's a start to a more comprehensive assessment of how transport and economic activity interrelate.

Santini, D. J.; Poyer, D. A. (Energy Systems); (Morehouse Coll.)

2008-01-01

325

Prophylactic respiratory physiotherapy after cardiac surgery: systematic review  

Microsoft Academic Search

Objective To assess whether respiratory physiotherapy prevents pulmonary complications after cardiac surgery. Data sources Searches through Medline, Embase, Cinahl, the Cochrane library, and bibliographies, for randomised trials comparing any type of prophylactic respiratory physiotherapy with another type or no intervention after cardiac surgery, with a follow up of at least two days, and reporting on respiratory outcomes. Review methods Investigators

Patrick Pasquina; Martin R Tramèr; Bernhard Walder

2003-01-01

326

Robotic-assisted cardiac surgery: Anesthetic and postoperative considerations  

Microsoft Academic Search

Objective: To assess the feasibility of endoscopic telemanipulated cardiac surgery and describe the anesthetic, postoperative, and surgical implications of minimally invasive robotic-assisted cardiac surgery. Design: Prospective study. Setting: Cardiovascular and transplant center, university hospital. Participants: Twenty patients (13 men, 7 women) scheduled for either coronary artery bypass graft surgery or valve surgery. Mean age was 53 ± 5 years (range,

Nicola D'Attellis; Didier Loulmet; Alain Carpentier; Alain Berrebi; Cyril Cardon; Renaud Severac-Bastide; Jean-Noel Fabiani; Denis Safran

2002-01-01

327

Cardiac Function in Patients with Early Cirrhosis during Maximal Beta-Adrenergic Drive: A Dobutamine Stress Study  

PubMed Central

Background and aim Cardiac dysfunction in patients with early cirrhosis is debated. We investigated potential cardiac dysfunction by assessing left ventricular systolic performance during a dobutamine stress test in patients with early cirrhosis. Patients and methods Nineteen patients with Child A and B cirrhosis (9 with non-alcoholic cirrhosis) and 7 matched controls were included. We used cardiac magnetic resonance imaging to assess left ventricular volumes and cardiac output (CO) at rest and during maximal heart rate induced by increasing dosages of dobutamine and atropine. Results Patients with cirrhosis and controls had an equal stress response, the heart rate and ejection fraction increased similarly and maximal heart rate was reached in all. At rest CO was higher in Child B patients than controls. During maximal stress, Child B patients had higher CO (10.6±2.7 vs. 8.0±1.8 L/min), left ventricle end diastolic volume (90±25 vs. 67±16 mL), left ventricular end diastolic volume (10±4 vs. 6±2 mL) and stroke volume (80±23 vs. 61±15 mL) than Child A patients. The systemic vascular resistance was lower in Child B than Child A patients (670±279 vs. 911±274 dyne*s*cm?5). The left ventricle mass increased by 5.6 gram per model for end stage liver disease (MELD) point. MELD score correlated with the end diastolic and systolic volume, CO, and stroke volume at rest and at stress (all p<0.05). Conclusion In patients with early cirrhosis the chronotropoic and inotropic response to pharmacological stress induced by dobutamine is normal. With progression of the disease, the mass of the heart increases along with increase in cardiac volumes. PMID:25279659

Krag, Aleksander; Bendtsen, Flemming; Dahl, Emilie Kristine; Kjaer, Andreas; Petersen, Claus Leth; M?ller, S?ren

2014-01-01

328

Sudden cardiac death  

Microsoft Academic Search

The rate of cardiac deaths that are sudden is approximately 50%, and decreases with age. The causes of sudden cardiac death are diverse, and are a function of age. In children and adolescents, coronary anomalies, hypertrophic cardiomyopathy and myocarditis are frequent substrates for lethal arrhythmias; in adults, coronary atherosclerosis and acquired forms of cardiomyopathy are the most common findings at

Renu Virmani; Allen P Burke; Andrew Farb

2001-01-01

329

Hybrid Pediatric Cardiac Surgery  

Microsoft Academic Search

Minimally invasive strategies can be expanded by combining standard surgical and interventional techniques. We performed a longitudinal prospective study of all pediatric patients who have undergone hybrid cardiac surgery at the University of Chicago Children's Hospital. Hybrid cardiac surgery was defined as combined catheter-based and surgical interventions in either one setting or in a planned sequential fashion within 24 hours.

E. A. Bacha; Z. M. Hijazi; Q. L. Cao; R. Abdulla; J. P. Starr; J. Quinones; P. Koenig; B. Agarwala

2005-01-01

330

Micromolded gelatin hydrogels for extended culture of engineered cardiac tissues  

E-print Network

Ltd. All rights reserved. 1. Introduction Cardiotoxicity is a leading cause of market withdrawal- diotoxicity is usually identified in animal models, such as mice [5,6] or dogs [7], that are exposed of cardiac output. Furthermore, studies with animals and animal cells are not always relevant to humans due

331

Functional cardiac tissue engineering  

PubMed Central

Heart attack remains the leading cause of death in both men and women worldwide. Stem cell-based therapies, including the use of engineered cardiac tissues, have the potential to treat the massive cell loss and pathological remodeling resulting from heart attack. Specifically, embryonic and induced pluripotent stem cells are a promising source for generation of therapeutically relevant numbers of functional cardiomyocytes and engineering of cardiac tissues in vitro. This review will describe methodologies for successful differentiation of pluripotent stem cells towards the cardiovascular cell lineages as they pertain to the field of cardiac tissue engineering. The emphasis will be placed on comparing the functional maturation in engineered cardiac tissues and developing heart and on methods to quantify cardiac electrical and mechanical function at different spatial scales. PMID:22397609

Liau, Brian; Zhang, Donghui; Bursac, Nenad

2013-01-01

332

Cardiac Risks and Complications of Noncardiac Surgery  

PubMed Central

When internists are consulted to assess risks and to aid in the perioperative management of surgical patients, they often can rely on substantial clinical data to guide the consultation. Perioperative cardiac risk can be estimated based on the severity of underlying heart failure, the occurrence of a recent myocardial infarction or various arrhythmias, the presence of aortic stenosis, the patient's age, the type of planned surgery (including whether it is an emergency or elective procedure), and the patient's general medical condition. Preoperative exercise testing or cardiac catheterization to assess risk are not routinely indicated, but perioperative hemodynamic monitoring to improve management is recommended in patients at high risk. Postoperative hypertension, arrhythmias, and heart failure commonly occur in the first 2 days after surgery, but the risk of myocardial infarction persists for at least 5 or 6 days after surgery. Effective perioperative consultation must include careful postoperative observation to detect cardiac complications at an early stage and to assist in their management.

Goldman, Lee

1983-01-01

333

Usefulness of the severity and extent of reversible perfusion defects during thallium-dipyridamole imaging for cardiac risk assessment before noncardiac surgery  

SciTech Connect

Thallium-dipyridamole imaging is a very sensitive test for predicting cardiac events after noncardiac surgery, but it lacks specificity. To improve specificity, a semiquantitative scoring system was developed that combined dipyridamole-induced reversible left ventricular dilatation with scintigraphic indexes for severity and extent of reversible perfusion defects. Using this scoring system, patients were classified into low, intermediate and high risk subgroups. Thallium-dipyridamole imaging was performed in 66 patients before major general and vascular surgery. Thirty-nine patients classified as low risk (30 with normal scans and 9 with fixed defects) underwent surgery uneventfully. Surgery was cancelled in 6 patients with extensive thallium redistribution and coronary angiography was performed because of severe coronary artery disease in 5 and idiopathic dilated cardiomyopathy in 1. In the remaining 21 patients with thallium redistribution, a positive statistical correlation (p = 0.001) between scintigraphic indexes of severity and extent, and cardiac events was noted. Using cutoff values for the scintigraphic indexes, patients with reversible defects could be classified into intermediate and high risk subgroups. Only 1 of 11 patients at intermediate risk developed a complication, whereas 8 of 10 patients at high risk had a postoperative event (7 deaths and 1 myocardial infarction). Thus, using scintigraphic indexes for severity and extent, patients with reversible defects can be stratified into an intermediate risk subgroup that can safely undergo surgery and a high risk subgroup that requires coronary angiography.

Lette, J.; Waters, D.; Lapointe, J.; Gagnon, A.; Picard, M.; Cerino, M.; Kerouac, M. (Maisonneuve-Rosemont Hospital, Montreal, Quebec (Canada))

1989-08-01

334

Quantitative assessment of brain tissue oxygenation in porcine models of cardiac arrest and cardiopulmonary resuscitation using hyperspectral near-infrared spectroscopy  

NASA Astrophysics Data System (ADS)

Near-infrared spectroscopy (NIRS) is a non-invasive tool to measure real-time tissue oxygenation in the brain. In an invasive animal experiment we were able to directly compare non-invasive NIRS measurements on the skull with invasive measurements directly on the brain dura matter. We used a broad-band, continuous-wave hyper-spectral approach to measure tissue oxygenation in the brain of pigs under the conditions of cardiac arrest, cardiopulmonary resuscitation (CPR), and defibrillation. An additional purpose of this research was to find a correlation between mortality due to cardiac arrest and inadequacy of the tissue perfusion during attempts at resuscitation. Using this technique we measured the changes in concentrations of oxy-hemoglobin [HbO2] and deoxy-hemoglobin [HHb] to quantify the tissue oxygenation in the brain. We also extracted cytochrome c oxidase changes ?[Cyt-Ox] under the same conditions to determine increase or decrease in cerebral oxygen delivery. In this paper we proved that applying CPR, [HbO2] concentration and tissue oxygenation in the brain increase while [HHb] concentration decreases which was not possible using other measurement techniques. We also discovered a similar trend in changes of both [Cyt-Ox] concentration and tissue oxygen saturation (StO2). Both invasive and non-invasive measurements showed similar results.

Lotfabadi, Shahin S.; Toronov, Vladislav; Ramadeen, Andrew; Hu, Xudong; Kim, Siwook; Dorian, Paul; Hare, Gregory M. T.

2014-03-01

335

Decreased heart rate variability in survivors of sudden cardiac death not associated with coronary artery disease  

Microsoft Academic Search

BACKGROUND--Although heart rate variability has already been studied in survivors of sudden cardiac death secondary to coronary artery disease, an assessment of heart rate variability in survivors of sudden cardiac death not associated with coronary artery disease has not been made. METHODS--10 patients with aborted sudden cardiac death not associated with coronary artery disease (seven patients with primary ventricular fibrillation

J Singh; M. H. Anderson; D. Katritsis; J. Sneddon; D. J. Statters; M. Malik; A. J. Camm

1994-01-01

336

Prognostic determinants of long-term survival in Japanese patients with cardiac sarcoidosis treated with prednisone  

Microsoft Academic Search

Cardiac involvement is an important prognostic factor in sarcoidosis, but reliable indicators of mortality risk in cardiac sarcoidosis are unstudied in a large number of patients. To determine the significant predictors of mortality and to assess the efficacy of corticosteroids, we analyzed clinical findings, treatment, and prognosis in 95 Japanese patients with cardiac sarcoidosis. Twenty of these 95 patients had

Yoshikazu Yazaki; Mitsuaki Isobe; Michiaki Hiroe; Shin-ichiro Morimoto; Shinya Hiramitsu; Takeshi Nakano; Tohru Izumi; Morie Sekiguchi

2001-01-01

337

Output optics for laser velocimeters  

NASA Technical Reports Server (NTRS)

Space savings are effected in the optical output system of a laser velocimeter. The output system is comprised of pairs of optical fibers having output ends from which a beam of laser light emerges, a transfer lens for each light beam, and at least one final (LV) lens for receiving the light passing through the transfer lenses and for focussing that light at a common crossing point or area. In order to closely couple the transfer lenses to the final lens, each transfer lens is positioned relative to the final lens receiving light therefrom such that the output waist of the corresponding beam received by the final lens from the transfer lens is a virtual waist located before the transfer lens.

Lynch, Dana H. (inventor); Gunter, William D. (inventor); Mcalister, Kenneth W. (inventor)

1993-01-01

338

World Input-Output Network  

E-print Network

Economic systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the multi-regional input-output (MRIO) tables at the global level. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we study the network properties of the so-called world input-output network (WION) and document its evolution over time. We are able to quantify not only some global network properties such as assortativity, clustering coefficient, and degree and strength distributions, but also its subgraph structure and dynamics by using community detection techniques. Over time, we detect a marked increase in cross-country connectivity of the production system, only temporarily interrupted by the 2008-2009 crisis. Moreover...

Cerina, Federica; Chessa, Alessandro; Riccaboni, Massimo

2014-01-01

339

Maximum output at minimum cost  

E-print Network

at generator output terminals, on low voltage side before transformer input terminals. Rotor Blades Tubular converters and PWM (Pulse Width Modulation) electronic control. Benefits: ®® Active and reactive power

Firestone, Jeremy

340

Output collapses and productivity destruction  

Microsoft Academic Search

In this paper we analyze the long-run relationship between output collapses—defined as GDP falling substantially below trend—and\\u000a total factor productivity (TFP). We use a panel of 76 developed and developing countries during the period 1960–2004 to identify\\u000a episodes of output collapse and estimate counterfactual post-collapse TFP trends. Collapses are concentrated in developing\\u000a countries, especially Africa and Latin America, and were

Juan S. Blyde; Christian Daude; Eduardo Fernández-Arias

2010-01-01

341

Chronic fatigue syndrome: comments on deconditioning, blood volume and resulting cardiac function  

PubMed Central

Cardiovascular and autonomic dysfunction have been suggested to underlie the symptoms accompanying CFS (chronic fatigue syndrome). In the present issue of Clinical Science, Hurwitz and co-workers have investigated whether deficits were present in cardiac output and blood volume in a cohort of patients with CFS and if these were linked to illness severity and sedentary lifestyle. The results clearly demonstrate reduced cardiac stroke volume and cardiac output in more severely afflicted patients with CFS, which is primarily attributable to a measurable reduction in blood volume. Similar findings are observed in microgravity and bed rest deconditioning, in forms of orthostatic intolerance and, to a lesser extent, in sedentary people. The circulatory consequences of reduced cardiac output may help to account for many of the findings of the syndrome. PMID:19534728

STEWART, Julian M.

2014-01-01

342

Impact of epoetin alfa on left ventricular structure, function, and pressure volume relations as assessed by cardiac magnetic resonance: the heart failure preserved ejection fraction (HFPEF) anemia trial.  

PubMed

Anemia, a common comorbidity in older adults with heart failure and a preserved ejection fraction (HFPEF), is associated with worse outcomes. The authors quantified the effect of anemia treatment on left ventricular (LV) structure and function as measured by cardiac magnetic resonance (CMR) imaging. A prospective, randomized single-blind clinical trial (NCT NCT00286182) comparing the safety and efficacy of epoetin alfa vs placebo for 24 weeks in which a subgroup (n=22) had cardiac magnetic resonance imaging (MRI) at baseline and after 3 and 6 months to evaluate changes in cardiac structure and function. Pressure volume (PV) indices were derived from MRI measures of ventricular volume coupled with sphygmomanometer-measured pressure and Doppler estimates of filling pressure. The end-systolic and end-diastolic PV relations and the area between them as a function of end-diastolic pressure, the isovolumic PV area (PVAiso), were calculated. Patients (75±10 years, 64% women) with HFPEF (EF=63%±15%) with an average hemoglobin of 10.3±1.1 gm/dL were treated with epoetin alfa using a dose-adjusted algorithm that increased hemoglobin compared with placebo (P<.0001). As compared with baseline, there were no significant changes in end-diastolic (-7±8 mL vs -3±8 mL, P=.81) or end-systolic (-0.4±2 mL vs -0.7±5 mL, P=.96) volumes at 6-month follow-up between epoetin alfa compared with placebo. LV function as measured based on EF (-1.5%±1.6% vs -2.6%±3.3%, P=.91) and pressure volume indices (PVAiso-EDP at 30 mm Hg, -5071±4308 vs -1662±4140, P=.58) did not differ between epoetin alfa and placebo. Administration of epoetin alfa to older adult patients with HFPEF resulted in a significant increase in hemoglobin, without evident change in LV structure, function, or pressure volume relationships as measured quantitatively using CMR imaging. PMID:23517485

Green, Philip; Babu, Benson A; Teruya, Sergio; Helmke, Stephen; Prince, Martin; Maurer, Mathew S

2013-01-01

343

Antithrombotic Therapy in Cardiac Embolism  

PubMed Central

Anticoagulation is indicated in most cardioembolic ischemic strokes for secondary prevention. In many cardiac conditions, anticoagulation is also indication for primary stroke prevention, mainly when associated to vascular risk factors. Anticoagulation should be started as soon as possible, as it is safe even in moderate acute strokes. The efficacy of early anticoagulation after cardioembolic stroke in relation to outcome has not been assessed adequately, but there is evidence from animal models and clinical studies that anticoagulation with unfractionated heparin is associated with a better outcome mediated in part by its anti-inflammatory properties. PMID:21804782

Cervera, Alvaro; Chamorro, Angel

2010-01-01

344

Modeling inherited cardiac disorders.  

PubMed

Advances in the understanding and treatment of cardiac disorders have been thwarted by the inability to study beating human cardiac cells in vitro. Induced pluripotent stem cells (iPSCs) bypass this hurdle by enabling the creation of patient-specific iPSC-derived cardiomyocytes (iPSC-CMs). These cells provide a unique platform to study cardiac diseases in vitro, especially hereditary cardiac conditions. To date, iPSC-CMs have been used to successfully model arrhythmic disorders, showing excellent recapitulation of cardiac channel function and electrophysiologic features of long QT syndrome types 1, 2, 3, and 8, and catecholaminergic polymorphic ventricular tachycardia (CPVT). Similarly, iPSC-CM models of dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM) have shown robust correlation of predicted morphologic, contractile, and electrical phenotypes. In addition, iPSC-CMs have shown some features of the respective phenotypes for arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), LEOPARD syndrome, Pompe's disease, and Friedriech's ataxia. In this review, we examine the progress of utilizing iPSC-CMs as a model for cardiac conditions and analyze the potential for the platform in furthering the biology and treatment of cardiac disorders.?? PMID:24632794

Sallam, Karim; Kodo, Kazuki; Wu, Joseph C

2014-01-01

345

Cardiac involvement in leptospirosis.  

PubMed

Leptospirosis is a neglected global disease with significant morbidity and mortality. Cardiac complications such as chest pain, arrhythmias, pulmonary oedema and refractory shock have been reported in patients with severe disease. However, the frequency and extent of cardiac involvement in leptospirosis, are under-reported and poorly understood. Multiple factors may contribute to clinical manifestations that suggest cardiac involvement, causing diagnostic confusion. A variety of electrocardiographic changes occur in leptospirosis, with atrial fibrillation, atrioventricular conduction blocks and non-specific ventricular repolarization abnormalities being the most common. Electrolyte abnormalities are likely to contribute to electrocardiographic changes; direct effects on Na(+)-K(+)-Cl(-) transporters in the renal tubules have been postulated. Echocardiographic evidence of myocardial dysfunction has not been adequately demonstrated. The diagnostic value of cardiac biomarkers is unknown. Histopathological changes in the myocardium have been clearly shown, with myocardial inflammation and vasculitis present in postmortem studies. Nonetheless, the pathophysiology of cardiac involvement in leptospirosis is poorly understood. Cardiac involvement, demonstrated electrocardiographically or clinically, tends to predict poor outcome. No specific therapies are available to prevent or treat cardiac involvement in leptospirosis; current management is based on correction of deranged homeostasis and supportive therapy. Evidence suggests that direct myocardial damage occurs in patients with severe leptospirosis, and further studies are recommended to elucidate its pathophysiology, clinical features and contribution to overall prognosis, and to identify appropriate diagnostic investigations and specific therapies. PMID:22818758

Navinan, Mitrakrishnan Rayno; Rajapakse, Senaka

2012-09-01

346

Cardiac Vagal Denervation in Hemodialysis Patients’  

Microsoft Academic Search

Heart rate variation is dependent upon an intact vagus nerve. Inherent beat-to-beat variability is expressed statistically as the mean square successive difference. Sinus arrhythmia is expressed as the standard deviation of the RR intervals. 19 normal volunteers and 19 nondiabetic hemodialysis patients were assessed for cardiac vagal innervation by monitoring heart rate variation on resting electrocardiograms. Comparison of the dialysis

Ellen D. Burgess

1982-01-01

347

Aspirin resistance following pediatric cardiac surgery  

Microsoft Academic Search

IntroductionAspirin is often used to prevent thrombosis in pediatric cardiac surgery. The primary study aim was to assess aspirin resistance in this context. Secondary aims were to evaluate (1) the relationship between elevated inflammatory markers and thrombosis and (2) aspirin's effect on these levels.

Jill M. Cholette; Lara Mamikonian; George M. Alfieris; Neil Blumberg; Norma B. Lerner

2010-01-01

348

Assessment of Hydraulic Performance and Biocompatibility of a MagLev Centrifugal Pump System Designed for Pediatric Cardiac or Cardiopulmonary Support  

PubMed Central

The treatment of children with life-threatening cardiac and cardiopulmonary failure is a large and underappreciated public health concern. We have previously shown that the CentriMag is a magnetically levitated centrifugal pump system, having the utility for treating adults and large children (1,500 utilized worldwide). We present here the Pedi-VAS, a pump system whose design was modified from the CentriMag to meet the physiological requirements of young pediatric and neonatal patients. The PediVAS is comprised of a single-use centrifugal blood pump, reusable motor, and console, and is suitable for right ventricular assist device (RVAD), left ventricular assist device (LVAD), biventricular assist device (BVAD), or extracorporeal membrane oxygenator (ECMO) applications. It is designed to operate without bearings, seals and valves, and without regions of blood stasis, friction, or wear. The PediVAS pump is compatible with the CentriMag hardware, although the priming volume was reduced from 31 to 14 ml, and the port size reduced from 3/8 to ¼ in. For the expected range of pediatric flow (0.3–3.0 L/min), the PediVAS exhibited superior hydraulic efficiency compared with the CentriMag. The PediVAS was evaluated in 14 pediatric animals for up to 30 days, demonstrating acceptable hydraulic function and hemocompatibility. The current results substantiate the performance and biocompatibility of the PediVAS cardiac assist system and are likely to support initiation of a US clinical trial in the future. PMID:18043164

Dasse, Kurt A.; Gellman, Barry; Kameneva, Marina V.; Woolley, Joshua R.; Johnson, Carl A.; Gempp, Thomas; Marks, John D.; Kent, Stella; Koert, Andrew; Richardson, J. Scott; Franklin, Steve; Snyder, Trevor A.; Wearden, Peter; Wagner, William R.; Gilbert, Richard J.; Borovetz, Harvey S.

2011-01-01

349

Assessment of hydraulic performance and biocompatibility of a MagLev centrifugal pump system designed for pediatric cardiac or cardiopulmonary support.  

PubMed

The treatment of children with life-threatening cardiac and cardiopulmonary failure is a large and underappreciated public health concern. We have previously shown that the CentriMag is a magnetically levitated centrifugal pump system, having the utility for treating adults and large children (1,500 utilized worldwide). We present here the PediVAS, a pump system whose design was modified from the CentriMag to meet the physiological requirements of young pediatric and neonatal patients. The PediVAS is comprised of a single-use centrifugal blood pump, reusable motor, and console, and is suitable for right ventricular assist device (RVAD), left ventricular assist device (LVAD), biventricular assist device (BVAD), or extracorporeal membrane oxygenator (ECMO) applications. It is designed to operate without bearings, seals and valves, and without regions of blood stasis, friction, or wear. The PediVAS pump is compatible with the CentriMag hardware, although the priming volume was reduced from 31 to 14 ml, and the port size reduced from 3/8 to (1/4) in. For the expected range of pediatric flow (0.3-3.0 L/min), the PediVAS exhibited superior hydraulic efficiency compared with the CentriMag. The PediVAS was evaluated in 14 pediatric animals for up to 30 days, demonstrating acceptable hydraulic function and hemocompatibility. The current results substantiate the performance and biocompatibility of the PediVAS cardiac assist system and are likely to support initiation of a US clinical trial in the future. PMID:18043164

Dasse, Kurt A; Gellman, Barry; Kameneva, Marina V; Woolley, Joshua R; Johnson, Carl A; Gempp, Thomas; Marks, John D; Kent, Stella; Koert, Andrew; Richardson, J Scott; Franklin, Steve; Snyder, Trevor A; Wearden, Peter; Wagner, William R; Gilbert, Richard J; Borovetz, Harvey S

2007-01-01

350

Complex Assessment of the Incidence and Risk Factors of Delirium in a Large Cohort of Cardiac Surgery Patients: A Single-Center 6-Year Experience  

PubMed Central

Background. Previous reports provided inconsistent data on the occurrence of postoperative delirium and emphasized its considerable impact on outcome. This study sought to evaluate the incidence and predictors of delirium, together with its relation to cerebral ischemia in a large cohort of cardiac surgery patients in a tertiary high-volume center. Methods and Results. Consecutive patients (n = 8792) were prospectively enrolled from 2003 to 2008. Exclusion criteria were history of psychiatric disorders, use of psychoactive drugs, alcohol abuse, and data incompleteness. Finally, 5781 patients were analyzed in terms of 100 perioperative patient-specific and treatment variables. The incidence of postoperative delirium (DSM IV criteria) was 4.1% and it coexisted with cerebral ischemia in 1.1% of patients. In bivariate analysis, 49 variables were significantly linked to postoperative delirium. Multivariate analysis confirmed that delirium was independently associated with postoperative stroke (logistic odds ratio (logOR) = 2.862, P = 0.004), any blood transfusions (logOR = 4.178, P < 0.0001), age > 65 years (logOR = 2.417, P = 0.002), carotid artery stenosis (logOR = 2.15, P = 0.01), urgent/emergent surgery (logOR = 1.982, P = 0.02), fasting glucose level, intraoperative oxygen partial pressure fluctuations, and hematocrit. Area under ROC curve for the model was 0.8933. Conclusions. Early identification of nonpsychiatric perioperative determinants of delirium facilitates its diagnosis and might help develop preventive strategies to improve long-term outcome after cardiac surgery procedures. PMID:24455731

Krzych, Lukasz J.; Wybraniec, Maciej T.; Krupka-Matuszczyk, Irena; Skrzypek, Michal; Bolkowska, Anna; Wilczynski, Miroslaw; Bochenek, Andrzej A.

2013-01-01

351

Cardiac muscle cells  

NSDL National Science Digital Library

Cardiac muscles are found only in the heart. They work together to bring deoxygenated blood in and push oxygenated blood out into the body. Essentially, they keep your heart pumping and your body alive.

Nathanael Reveal (None;)

2007-07-02

352

Cardiac ablation procedures  

MedlinePLUS

... 4(6):816-61. Miller JM, Zipes DP. Therapy for cardiac arrhythmias. In: Libby P, Bonow RO, Mann DL, Zipes DP, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine . 8th ed. Philadelphia, ...

353

Integrative Cardiac Health Project.  

National Technical Information Service (NTIS)

The Integrative Cardiac Health Project (ICHP) aims to lead the way in Cardiovascular Disease (CVD) Prevention by conducting novel research utilizing a Systems Biology / personalized medicine design to discover and develop practical, effective and preempti...

A. H. Nixon, M. N. Vernalis

2013-01-01

354

Integrative Cardiac Health Project.  

National Technical Information Service (NTIS)

The Integrative Cardiac Health Project (ICHP) aims to lead the way in Cardiovascular Disease (CVD) Prevention by conducting novel research utilizing a Systems Biology / personalized medicine design to discover and develop practical, effective and preempti...

A. H. NIxon, M. N. Vernalis

2011-01-01

355

Integrative Cardiac Health Project.  

National Technical Information Service (NTIS)

The Integrative Cardiac Health Project (ICHP) aims to lead the way in Cardiovascular Disease (CVD) Prevention by conducting novel research utilizing a Systems Biology / personalized medicine design to discover and develop practical, effective and preempti...

A. H. Nixon, M. N. Vernalis

2012-01-01

356

Functional cardiac MR imaging  

NASA Astrophysics Data System (ADS)

Undersampled projection reconstruction acquisitions are investigated for use in functional cardiac MR imaging. 256×256 resolution is obtainable using only 64 projections, with acceptable artifact level. Reduced FOV techniques decrease artifact. Variable angular sampling using projection reconstruction is investigated.

Peters, Dana C.; Epstein, Frederick H.; McVeigh, Elliot R.

2000-10-01

357

Defining cardiac adaptations and safety of endurance training in patients with m.3243A>G-related mitochondrial disease??????  

PubMed Central

Background Cardiac hypertrophic remodelling and systolic dysfunction are common in patients with mitochondrial disease and independent predictors of morbidity and early mortality. Endurance exercise training improves symptoms and skeletal muscle function, yet cardiac adaptations are unknown. Methods and results Before and after 16-weeks of training, exercise capacity, cardiac magnetic resonance imaging and phosphorus-31 spectroscopy, disease burden, fatigue, quality of life, heart rate variability (HRV) and blood pressure variability (BPV) were assessed in 10 adult patients with m.3243A>G-related mitochondrial disease, and compared to age- and gender-matched sedentary control subjects. At baseline, patients had increased left ventricular mass index (LVMI, p < 0.05) and LV mass to end-diastolic volume ratio, and decreased longitudinal shortening and myocardial phosphocreatine/adenosine triphosphate ratio (all p < 0.01). Peak arterial–venous oxygen difference (p < 0.05), oxygen uptake (VO2) and power were decreased in patients (both p < 0.01) with no significant difference in cardiac power output. All patients remained stable and completed ? 80% sessions. With training, there were similar proportional increases in peak VO2, anaerobic threshold and work capacity in patients and controls. LVMI increased in both groups (p < 0.01), with no significant effect on myocardial function or bioenergetics. Pre- and post-exercise training, HRV and BPV demonstrated increased low frequency and decreased high frequency components in patients compared to controls (all p < 0.05). Conclusion Patients with mitochondrial disease and controls achieved similar proportional benefits of exercise training, without evidence of disease progression, or deleterious effects on cardiac function. Reduced exercise capacity is largely mediated through skeletal muscle dysfunction at baseline and sympathetic over-activation may be important in pathogenesis. PMID:23742928

Bates, Matthew G.D.; Newman, Jane H.; Jakovljevic, Djordje G.; Hollingsworth, Kieren G.; Alston, Charlotte L.; Zalewski, Pawel; Klawe, Jacek J.; Blamire, Andrew M.; MacGowan, Guy A.; Keavney, Bernard D.; Bourke, John P.; Schaefer, Andrew; McFarland, Robert; Newton, Julia L.; Turnbull, Douglass M.; Taylor, Robert W.; Trenell, Michael I.; Gorman, Grainne S.

2013-01-01

358

Cardiac arrest during pregnancy.  

PubMed

Cardiac arrest is a rare event during pregnancy. The pregnant population represents a unique subset of cardiac arrest victims. Not only are there unique causes of circulatory collapse during the pregnant state, but the physiological modifications to the maternal physiology during pregnancy require specific modifications to the standard management of the arrest. Lastly, the pregnant victim presents herself with the challenges of a second patient who needs to be considered in the decision-making process. PMID:25314090

Montufar-Rueda, Carlos; Gei, Alfredo

2014-12-01

359

Impairment of cardiac function and energetics in experimental renal failure.  

PubMed Central

Cardiac function and energetics in experimental renal failure in the rat (5/6 nephrectomy) have been investigated by means of an isolated perfused working heart preparation and an isometric Langendorff preparation using 31P nuclear magnetic resonance (31P NMR). 4 wk after nephrectomy cardiac output of isolated hearts perfused with Krebs-Henseleit buffer was significantly lower (P < 0.0001) at all levels of preload and afterload in the renal failure groups than in the pair-fed sham operated control group. In control hearts, cardiac output increased with increases in perfusate calcium from 0.73 to 5.61 mmol/liter whereas uremic hearts failed in high calcium perfusate. Collection of 31P NMR spectra from hearts of renal failure and control animals during 30 min normoxic Langendorff perfusion showed that basal phosphocreatine was reduced by 32% to 4.7 mumol/g wet wt (P < 0.01) and the phosphocreatine to ATP ratio was reduced by 32% (P < 0.01) in uremic hearts. During low flow ischemia, there was a substantial decrease in phosphocreatine in the uremic hearts and an accompanying marked increase in release of inosine into the coronary effluent (14.9 vs 6.1 microM, P < 0.01). We conclude that cardiac function is impaired in experimental renal failure, in association with abnormal cardiac energetics and increased susceptibility to ischemic damage. Disordered myocardial calcium utilization may contribute to these derangements. PMID:8254048

Raine, A E; Seymour, A M; Roberts, A F; Radda, G K; Ledingham, J G

1993-01-01

360

Update on cardiac imaging techniques 2013.  

PubMed

Cardiac imaging is a cornerstone of diagnosis in heart conditions, and an essential tool for assessing prognosis and establishing treatment decisions. This year, echocardiography stands out as a guide in interventional procedures and in choosing the size of the prosthesis. It is also proving to be a valuable technique in low-flow, low-gradient aortic stenosis. Three-dimensional echocardiography is advancing our knowledge of cardiac anatomy and valvular measurements. The parameters indicating tissue deformation have predictive power in valve disease and in the follow-up of drug-induced cardiotoxicity. Single-photon emission computed tomography and positron emission tomography are proving useful in ischemic heart disease and in the diagnosis of cardiac inflammation and infections. The role of computed tomography has been strengthened in noninvasive coronary angiography, the emergency room management of chest pain, assessment of chronic occlusions, and morphologic study of coronary plaque. Cardiac magnetic resonance imaging remains the gold standard for tissue characterization in ischemic heart disease and cardiomyopathies, and is assuming a greater role in stress studies and in the assessment of myocardial viability. PMID:24795120

García-Orta, Rocío; Mahía-Casado, Patricia; Gómez de Diego, José J; Barba-Cosials, Joaquín; Rodriguez-Palomares, José F; Aguadé-Bruix, Santiago; Candell-Riera, Jaume

2014-02-01

361

Cardiac tissue engineering using perfusion bioreactor systems  

PubMed Central

This protocol describes tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cell populations on porous scaffolds (in some cases with an array of channels) and bioreactors with perfusion of culture medium (in some cases supplemented with an oxygen carrier). The overall approach is ‘biomimetic’ in nature as it tends to provide in vivo-like oxygen supply to cultured cells and thereby overcome inherent limitations of diffusional transport in conventional culture systems. In order to mimic the capillary network, cells are cultured on channeled elastomer scaffolds that are perfused with culture medium that can contain oxygen carriers. The overall protocol takes 2–4 weeks, including assembly of the perfusion systems, preparation of scaffolds, cell seeding and cultivation, and on-line and end-point assessment methods. This model is well suited for a wide range of cardiac tissue engineering applications, including the use of human stem cells, and high-fidelity models for biological research. PMID:18388955

Radisic, Milica; Marsano, Anna; Maidhof, Robert; Wang, Yadong; Vunjak-Novakovic, Gordana

2009-01-01

362

Electrical stimulation systems for cardiac tissue engineering.  

PubMed

We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

2009-01-01

363

Electrical stimulation systems for cardiac tissue engineering  

PubMed Central

We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures. PMID:19180087

Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

2009-01-01

364

Atherosclerotic renal artery stenosis is prevalent in cardiorenal patients but not associated with left ventricular function and myocardial fibrosis as assessed by cardiac magnetic resonance imaging  

PubMed Central

Background Atherosclerotic renal artery stenosis (ARAS) is common in cardiovascular diseases and associated with hypertension, renal dysfunction and/or heart failure. There is a paucity of data about the prevalence and the role of ARAS in the pathophysiology of combined chronic heart failure (CHF) and chronic kidney disease (CKD). We investigated the prevalence in patients with combined CHF/CKD and its association with renal function, cardiac dysfunction and the presence and extent of myocardial fibrosis. Methods The EPOCARES study (ClinTrialsNCT00356733) investigates the role of erythropoietin in anaemic patients with combined CHF/CKD. Eligible subjects underwent combined cardiac magnetic resonance imaging (cMRI), including late gadolinium enhancement, with magnetic resonance angiography of the renal arteries (MRA). Results MR study was performed in 37 patients (median age 74?years, eGFR 37.4?±?15.6?ml/min, left ventricular ejection fraction (LVEF) 43.3?±?11.2%), of which 21 (56.8%) had ARAS (defined as stenosis >50%). Of these 21 subjects, 8 (21.6%) had more severe ARAS >70% and 8 (21.6%) had a bilateral ARAS >50% (or previous bilateral PTA). There were no differences in age, NT-proBNP levels and medication profile between patients with ARAS versus those without. Renal function declined with the severity of ARAS (p?=?0.03), although this was not significantly different between patients with ARAS versus those without. Diabetes mellitus was more prevalent in patients without ARAS (56.3%) against those with ARAS (23.8%) (p?=?0.04). The presence and extent of late gadolinium enhancement, depicting myocardial fibrosis, did not differ (p?=?0.80), nor did end diastolic volume (p?=?0.60), left ventricular mass index (p?=?0.11) or LVEF (p?=?0.15). Neither was there a difference in the presence of an ischemic pattern of late enhancement in patients with ARAS versus those without. Conclusions ARAS is prevalent in combined CHF/CKD and its severity is associated with a decline in renal function. However, its presence does not correlate with a worse LVEF, a higher left ventricular mass or with the presence and extent of myocardial fibrosis. Further research is required for the role of ARAS in the pathophysiology of combined chronic heart and renal failure. PMID:22989293

2012-01-01

365

Cardiac Origins of the Postural Orthostatic Tachycardia Syndrome  

PubMed Central

Objectives To test the hypothesis that a small heart coupled with reduced blood volume contributes to the Postural Tachycardia Syndrome (POTS), while exercise training improves this syndrome. Background Patients with POTS have marked increases in heart rate during orthostasis. However, the underlying mechanisms are unknown and the effective therapy is uncertain. Methods Twenty-seven POTS patients underwent autonomic function tests, cardiac MRI, and blood volume measurements. Twenty-five of them participated in a 3-mo specially designed exercise training program with 19 completing the program; these patients were reevaluated after training. Results were compared with those of 16 healthy controls. Results Upright heart rate and total peripheral resistance were greater, while stroke volume and cardiac output were smaller in patients than controls. Baroreflex function was similar between groups. Left ventricular mass (median [25%, 75%], 1.26 [1.12, 1.37] vs 1.45 [1.34, 1.57] g/kg; P<0.01) and blood volume (60 [54, 64] vs 71 [65, 78] ml/kg; P<0.01) were smaller in patients than controls. Exercise training increased left ventricular mass and blood volume by ~12% and ~7%, and decreased upright heart rate by 9 [1, 17] bpm. Ten out of 19 patients no longer met POTS criteria after training, while patients’ Quality of Life assessed by Short-Form 36 was improved in all patients after training. Conclusions Autonomic function was intact in POTS patients. The marked tachycardia during orthostasis was attributable to a small heart coupled with reduced blood volume. Exercise training improved or even cured this syndrome in the majority of patients. It seems reasonable to offer POTS a new name based on its underlying pathophysiology – “The Grinch Syndrome”, because in this famous children’s book by Dr. Seuss, the main character had a heart that was “two sizes too small.” PMID:20579544

Fu, Qi; VanGundy, Tiffany B.; Galbreath, M. Melyn; Shibata, Shigeki; Jain, Manish; Hastings, Jeffrey L.; Bhella, Paul S.; Levine, Benjamin D.

2010-01-01

366

Cardiac norepinephrine kinetics in hypertrophic cardiomyopathy  

SciTech Connect

We examined the uptake and release of norepinephrine in the cardiac circulation and other regional vascular beds in 11 patients with hypertrophic cardiomyopathy (HCM) and in 10 control subjects during simultaneous infusion of tracer-labeled norepinephrine and isoproterenol. Cardiac neuronal uptake of norepinephrine was assessed by comparing regional removal of tracer-labeled norepinephrine with that of tracer-labeled isoproterenol (which is not a substrate for neuronal uptake) and by the relation between production of dihydroxyphenylglycol (DHPG), an exclusively intraneuronal metabolite of norepinephrine, and regional spillover of norepinephrine. Cardiac extraction of norepinephrine averaged 59 +/- 17% in the patients with HCM, significantly less than in the control subjects (79 +/- 13%, p less than 0.05), whereas cardiac extraction of isoproterenol was similar in the two groups (13 +/- 23% versus 13 +/- 14%), indicating that neuronal uptake of norepinephrine was decreased in the patients with HCM. The cardiac arteriovenous difference in norepinephrine was significantly larger in the patients with HCM than in the control subjects (73 +/- 77 versus 13 +/- 50 pg/ml, p less than 0.05), as was the product of the arteriovenous difference in norepinephrine and coronary blood flow (7.3 +/- 7.3 versus 0.8 +/- 3.0 ng/min, p less than 0.05).

Brush, J.E. Jr.; Eisenhofer, G.; Garty, M.; Stull, R.; Maron, B.J.; Cannon, R.O. III; Panza, J.A.; Epstein, S.E.; Goldstein, D.S.

1989-04-01

367

Influence of Cardiac Decentralization on Cardioprotection  

PubMed Central

The role of cardiac nerves on development of myocardial tissue injury after acute coronary occlusion remains controversial. We investigated whether acute cardiac decentralization (surgical) modulates coronary flow reserve and myocardial protection in preconditioned dogs subject to ischemia-reperfusion. Experiments were conducted on four groups of anesthetised, open-chest dogs (n?=?32): 1- controls (CTR, intact cardiac nerves), 2- ischemic preconditioning (PC; 4 cycles of 5-min IR), 3- cardiac decentralization (CD) and 4- CD+PC; all dogs underwent 60-min coronary occlusion and 180-min reperfusion. Coronary blood flow and reactive hyperemic responses were assessed using a blood volume flow probe. Infarct size (tetrazolium staining) was related to anatomic area at risk and coronary collateral blood flow (microspheres) in the anatomic area at risk. Post-ischemic reactive hyperemia and repayment-to-debt ratio responses were significantly reduced for all experimental groups; however, arterial perfusion pressure was not affected. Infarct size was reduced in CD dogs (18.6±4.3; p?=?0.001, data are mean±1SD) compared to 25.2±5.5% in CTR dogs and was less in PC dogs as expected (13.5±3.2 vs. 25.2±5.5%; p?=?0.001); after acute CD, PC protection was conserved (11.6±3.4 vs. 18.6±4.3%; p?=?0.02). In conclusion, our findings provide strong evidence that myocardial protection against ischemic injury can be preserved independent of extrinsic cardiac nerve inputs. PMID:24236106

Kingma, John G.; Simard, Denys; Voisine, Pierre; Rouleau, Jacques R.

2013-01-01

368

Abnormal cardiac enzymes in systemic sclerosis: a report of four patients and review of the literature.  

PubMed

Cardiac involvement in systemic sclerosis (SSc) is heterogeneous and can include primary involvement of the myocardium, pericardium and coronary arteries or be secondary to cardiac complications of pulmonary and renal disease. Primary cardiac involvement in SSc is uncommon but can result in ventricular dysfunction, organ failure, arrhythmias and death. It can remain clinically silent and the prevalence is likely to be under-reported. We report four cases of SSc associated with a raised serum troponin T (TnT), in a proportion of whom cardiac MRI myocardial abnormalities were detected. These cases highlight the heterogeneity of cardiac involvement in SSc, the role of cardiac MRI and promising biochemical responses to immunosuppression. Cardiac biomarkers such as TnT may be useful screening tools to identify subclinical cardiac disease and assess response to therapeutic intervention. PMID:24091585

Vasta, B; Flower, V; Bucciarelli-Ducci, C; Brown, S; Korendowych, E; McHugh, N J; Pauling, J D

2014-03-01

369

Multi-Output Battery Cells  

E-print Network

+ + + _ _ _ Fig.2 Multi-output SC (MoSC) based power management system. Intermediate bus Battery cells LDO loads power management system. A LOW-VOLUME POWER MANAGEMENT MODULE FOR PORTABLE APPLICATIONS BASED ON A MULTI,prodic}@ele.utoronto.ca Abstract-- This paper introduces a 2-stage power management architecture for battery powered portable

Prodiæ, Aleksandar

370

Viewing Output With IRIS Explorer  

E-print Network

combination of components may be displayed together. The user may view the output from any angle or distance pages or help files for use on other machines. After reading this overview, you may wish to run through via anonymous ftp from: bishop.stanford.edu in the directory /pub/p3dexplorer These tools may

Cooke, Michele

371

Output prediction of cone crushers  

Microsoft Academic Search

The output prediction of cone crushers has been focused on both by the aggregate producing industry and the mining industry as the demands for higher quality and lower costs increase. In this paper a method for prediction of cone crusher performance is presented By using the method both product size distributions and total capacity can be predicted. By combining these

C. M. Evertsson

1998-01-01

372

Transcriptional assessment by microarray analysis and large-scale meta-analysis of the metabolic capacity of cardiac and skeletal muscle tissues to cope with reduced nutrient availability in Gilthead Sea Bream (Sparus aurata L.).  

PubMed

The effects of nutrient availability on the transcriptome of cardiac and skeletal muscle tissues were assessed in juvenile gilthead sea bream fed with a standard diet at two feeding levels: (1) full ration size and (2) 70 % satiation followed by a finishing phase at the maintenance ration. Microarray analysis evidenced a characteristic transcriptomic profile for each muscle tissue following changes in oxidative capacity (heart?>?red skeletal muscle?>?white skeletal muscle). The transcriptome of heart and secondly that of red skeletal muscle were highly responsive to nutritional changes, whereas that of glycolytic white skeletal muscle showed less ability to respond. The highly expressed and nutritionally regulated genes of heart were mainly related to signal transduction and transcriptional regulation. In contrast, those of white muscle were enriched in gene ontology (GO) terms related to proteolysis and protein ubiquitination. Microarray meta-analysis using the bioinformatic tool Fish and Chips ( http://fishandchips.genouest.org/index.php ) showed the close association of a representative cluster of white skeletal muscle with some of cardiac and red skeletal muscle, and many GO terms related to mitochondrial function appeared to be common links between them. A second round of cluster comparisons revealed that mitochondria-related GOs also linked differentially expressed genes of heart with those of liver from cortisol-treated gilthead sea bream. These results show that mitochondria are among the first responders to environmental and nutritional stress stimuli in gilthead sea bream, and functional phenotyping of this cellular organelle is highly promising to obtain reliable markers of growth performance and well-being in this fish species. PMID:24626932

Calduch-Giner, Josep A; Echasseriau, Yann; Crespo, Diego; Baron, Daniel; Planas, Josep V; Prunet, Patrick; Pérez-Sánchez, Jaume

2014-08-01

373

The prognostic value of cardiac dysfunction assessed by bedside echocardiography in critically ill patients with COPD requiring mechanical ventilation: a study protocol  

PubMed Central

Introduction Chronic obstructive lung disease is not only a major cause of morbidity and mortality, but is also the major reason for intensive care unit (ICU) admission. Cardiac function is often impaired in this disease, but its association with clinical outcome has not been fully established. Methods and analysis This is a prospective observational study conducted in a 47-bed mixed ICU of a tertiary academic teaching hospital. The study will be performed from January 2014 to December 2015. All patients meeting the diagnostic criteria of acute exacerbation of chronic obstructive pulmonary disease and admitted to the ICU are potentially eligible for the present study. The relevant demographics and laboratory measurements have been obtained. Transthoracic echocardiography was performed immediately after ICU admission by experienced intensivists. The Cox proportional hazard regression model has been fitted by using a stepwise forward selection and backward elimination technique. If linear assumption is not satisfied, the linear spline function will be used. Ethics and dissemination The study protocol was approved by the ethics committee of Jinhua municipal central hospital. The results will be published in a peer-reviewed journal and shared with the worldwide medical community. Trial registration number The study protocol is registered at ClinicalTrials.gov (NCT02099279). PMID:25256186

Zhang, Zhongheng; Chen, Lin; Chen, Kun; Ni, Hongying

2014-01-01

374

Microfabricated perfusable cardiac biowire: a platform that mimics native cardiac bundle.  

PubMed

Tissue engineering enables the generation of three-dimensional (3D) functional cardiac tissue for pre-clinical testing in vitro, which is critical for new drug development. However, current tissue engineering methods poorly recapitulate the architecture of oriented cardiac bundles with supporting capillaries. In this study, we designed a microfabricated bioreactor to generate 3D micro-tissues, termed biowires, using both primary neonatal rat cardiomyocytes and human embryonic stem cell (hESC) derived cardiomyocytes. Perfusable cardiac biowires were generated with polytetrafluoroethylene (PTFE) tubing template, and were integrated with electrical field stimulation using carbon rod electrodes. To demonstrate the feasibility of this platform for pharmaceutical testing, nitric oxide (NO) was released from perfused sodium nitroprusside (SNP) solution and diffused through the tubing. The NO treatment slowed down the spontaneous beating of cardiac biowires based on hESC derived cardiomyocytes and degraded the myofibrillar cytoskeleton of the cardiomyocytes within the biowires. The biowires were also integrated with electrical stimulation using carbon rod electrodes to further improve phenotype of cardiomyocytes, as indicated by organized contractile apparatus, higher Young's modulus, and improved electrical properties. This microfabricated platform provides a unique opportunity to assess pharmacological effects on cardiac tissue in vitro by perfusion in a cardiac bundle model, which could provide improved physiological relevance. PMID:24352498

Xiao, Yun; Zhang, Boyang; Liu, Haijiao; Miklas, Jason W; Gagliardi, Mark; Pahnke, Aric; Thavandiran, Nimalan; Sun, Yu; Simmons, Craig; Keller, Gordon; Radisic, Milica

2014-03-01

375

Vasoplegia during cardiac surgery: current concepts and management.  

PubMed

Vasoplegic syndrome (VS) is a recognized and relatively common complication of cardiopulmonary bypass (CPB), appearing with an incidence ranging between 5% and 25%. It is characterized by significant hypotension, high or normal cardiac outputs and low systemic vascular resistance (SVR), and increased requirements for fluids and vasopressors during or after CPB. Patients developing VS are at increased risk for death and other major complications following cardiac surgery. This review will focus on the pathophysiology and contemporary strategies of treating VS encountered after CPB. PMID:21092891

Fischer, Gregory W; Levin, Mathew A

2010-01-01

376

Berberine attenuates cardiac dysfunction in hyperglycemic and hypercholesterolemic rats.  

PubMed

The positive effects of berberine (30 mg/kg/day, i.g. for 6 weeks) on cardiac dysfunction were evaluated in the rat model of hyperglycemia and hypercholesterolemia. Hyperglycemia and hypercholesterolemia were induced by feeding high-sucrose/fat diet (HSFD) consisting of 20% sucrose, 10% lard, 2.5% cholesterol, 1% bile salt for 12 weeks and streptozotocin (30 mg/kg, i.p.). The plasma sugar, total cholesterol, and triglyceride levels were significantly increased (422, 194 and 82%, respectively) in the HSFD/streptozotocin-treated rats, when compared with control animals receiving normal diet and vehicle. Berberine treatment reduced the plasma sugar and lipid levels by 24-69% in the rat model of hyperglycemia and hypercholesterolemia. Cardiac functions signed as values of cardiac output, left ventricular systolic pressure, the maximum rate of myocardial contraction (+dp/dtmax), left ventricular end diastolic pressure and the maximum rate of myocardial diastole (-dp/dtmax) were injured by 16-55% in the hyperglycemic/hypercholesterolemic rats. Berberine increased cardiac output, left ventricular systolic pressure and +dp/dtmax by 64, 16 and 79%, but decreased left ventricular end diastolic pressure and -dp/dtmax by 121 and 61% in the rats receiving HSFD/streptozotocin, respectively, when compared with the drug-untreated rats of hyperglycemia and hypercholesterolemia. Berberine caused significant increase in cardiac fatty acid transport protein-1 (159%), fatty acid transport proteins (56%), fatty acid beta-oxidase (52%), as well as glucose transporter-4 and peroxisome proliferator-activated receptor-? (PPAR?), but decrease in PPAR? mRNA and protein expression in hyperglycemic/hypercholesterolemic rats. These results indicated that berberine exerted protective effects on cardiac dysfunction induced by hyperglycemia/hypercholesterolemia through alleviating cardiac lipid accumulation and promoting glucose transport. PMID:21458442

Dong, Shi-Fen; Hong, Ying; Liu, Ming; Hao, Ying-Zhi; Yu, Hai-Shi; Liu, Yang; Sun, Jian-Ning

2011-06-25

377

Ventricular hemodynamics using cardiac computed tomography and optical flow method.  

PubMed

Ventricular hemodynamics plays an important role in assessing cardiac function in clinical practice. The aim of this study was to determine the ventricular hemodynamics based on contrast movement in the left ventricle (LV) between the phases in a cardiac cycle recorded using an electrocardiography (ECG) with cardiac computed tomography (CT) and optical flow method. Cardiac CT data were acquired at 120 kV and 280 mA with a 350 ms gantry rotation, which covered one cardiac cycle, on the 640-slice CT scanner with ECG for a selected patient without heart disease. Ventricular hemodynamics (mm/phase) were calculated using the optical flow method based on contrast changes with ECG phases in anterior-posterior, lateral and superior-inferior directions. Local hemodynamic information of the LV with color coating was presented. The visualization of the functional information made the hemodynamic observation easy. PMID:24463391

Lin, Yang-Hsien; Huang, Yung-Hui; Lin, Kang-Ping; Liu, Juhn-Cherng; Huang, Tzung-Chi

2014-01-01

378

Health Risk Assessment for Air Pollutants: Alterations in Lung and Cardiac Gene Expression in Mice Exposed to Milano Winter Fine Particulate Matter (PM2.5)  

PubMed Central

Oxidative stress, pulmonary and systemic inflammation, endothelial cell dysfunction, atherosclerosis and cardiac autonomic dysfunction have been linked to urban particulate matter exposure. The chemical composition of airborne pollutants in Milano is similar to those of other European cities though with a higher PM2.5 fraction. Milano winter fine particles (PM2.5win) are characterized by the presence of nitrate, organic carbon fraction, with high amount of polycyclic aromatic hydrocarbons and elements such as Pb, Al, Zn, V, Fe, Cr and others, with a negligible endotoxin presence. In BALB/c mice, we examined, at biochemical and transcriptomic levels, the adverse effects of repeated Milano PM2.5win exposure in lung and heart. We found that ET-1, Hsp70, Cyp1A1, Cyp1B1 and Hsp-70, HO-1, MPO respectively increased within lung and heart of PM2.5win-treated mice. The PM2.5win exposure had a strong impact on global gene expression of heart tissue (181 up-regulated and 178 down-regulated genes) but a lesser impact on lung tissue (14 up-regulated genes and 43 down-regulated genes). Focusing on modulated genes, in lung we found two- to three-fold changes of those genes related to polycyclic aromatic hydrocarbons exposure and calcium signalling. Within heart the most striking aspect is the twofold to threefold increase in collagen and laminin related genes as well as in genes involved in calcium signaling. The current study extends our previous findings, showing that repeated instillations of PM2.5win trigger systemic adverse effects. PM2.5win thus likely poses an acute threat primarily to susceptible people, such as the elderly and those with unrecognized coronary artery or structural heart disease. The study of genomic responses will improve understanding of disease mechanisms and enable future clinical testing of interventions against the toxic effects of air pollutant. PMID:25296036

Battaglia, Cristina; Cifola, Ingrid; Mangano, Eleonora; Mantecca, Paride; Camatini, Marina; Palestini, Paola

2014-01-01

379

Standardized multiple output power supply  

NASA Technical Reports Server (NTRS)

A comprehensive program to develop a prototype model of a standardized multiple output power supply for use in space flight applications is described. The prototype unit was tested and evaluated to assure that the design would provide near optimum performance for the planned application. The prototype design used a dc-to-dc converter incorporating reqenerative current feedback with a time-ratio controlled duty cycle to achieve high efficiency over a wide variation of input voltage and output loads. The packaging concept uses a mainframe capable of accommodating up to four inverter/regulator modules with one common input filter and housekeeping module. Each inverter/regulator module provides a maximum of 100 watts or 10 amperes. Each module is adaptable to operate at any voltage between 4.0 volts and 108 volts. The prototype unit contains +5, + or - 15 and +28 volt modules.

Ragusa, E. V.

1975-01-01

380

Microgyroscope with closed loop output  

NASA Technical Reports Server (NTRS)

A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.

Challoner, A. Dorian (Inventor); Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor); Cargille, Donald R. (Inventor)

2002-01-01

381

Thymic output, ageing and zinc  

Microsoft Academic Search

The role of the thymus is vital for orchestration of T-cell development and maturation. With increasing age the thymus undergoes a process of involution which results in a reduction in thymic size, function and output. Until relatively recent it was not feasible to accurately measure the magnitude of age-related loss of thymic function. With the discovery of T-cell receptor excision

Wayne A Mitchell; Irene Meng; Stuart A Nicholson; Richard Aspinall

2006-01-01

382

Minimal output sets for identifiability.  

PubMed

Ordinary differential equation models in biology often contain a large number of parameters that must be determined from measurements by parameter estimation. For a parameter estimation procedure to be successful, there must be a unique set of parameters that can have produced the measured data. This is not the case if a model is not uniquely structurally identifiable with the given set of outputs selected as measurements. In designing an experiment for the purpose of parameter estimation, given a set of feasible but resource-consuming measurements, it is useful to know which ones must be included in order to obtain an identifiable system, or whether the system is unidentifiable from the feasible measurement set. We have developed an algorithm that, from a user-provided set of variables and parameters or functions of them assumed to be measurable or known, determines all subsets that when used as outputs give a locally structurally identifiable system and are such that any output set for which the system is structurally identifiable must contain at least one of the calculated subsets. The algorithm has been implemented in Mathematica and shown to be feasible and efficient. We have successfully applied it in the analysis of large signalling pathway models from the literature. PMID:22609467

Anguelova, Milena; Karlsson, Johan; Jirstrand, Mats

2012-09-01

383

Pediatric sudden cardiac arrest.  

PubMed

Pediatric sudden cardiac arrest (SCA), which can cause sudden cardiac death if not treated within minutes, has a profound effect on everyone: children, parents, family members, communities, and health care providers. Preventing the tragedy of pediatric SCA, defined as the abrupt and unexpected loss of heart function, remains a concern to all. The goal of this statement is to increase the knowledge of pediatricians (including primary care providers and specialists) of the incidence of pediatric SCA, the spectrum of causes of pediatric SCA, disease-specific presentations, the role of patient and family screening, the rapidly evolving role of genetic testing, and finally, important aspects of secondary SCA prevention. This statement is not intended to address sudden infant death syndrome or sudden unexplained death syndrome, nor will specific treatment of individual cardiac conditions be discussed. This statement has been endorsed by the American College of Cardiology, the American Heart Association, and the Heart Rhythm Society. PMID:22451713

2012-04-01

384

Overload protection circuit for output driver  

Microsoft Academic Search

A protection circuit for preventing excessive power dissipation in an output transistor whose conduction path is connected between a power terminal and an output terminal. The protection circuit includes means for sensing the application of a turn on signal to the output transistor and the voltage at the output terminal. When the turn on signal is maintained for a period

Roger G

1982-01-01

385

Constraints for Input\\/Output Logics  

Microsoft Academic Search

In a previous paper we developed a general theory of input\\/output logics. These are operations resembling inference, but where inputs need not be included among outputs, and outputs need not be reusable as inputs. In the present paper we study what happens when they are constrained to render output consistent with input. This is of interest for deontic logic, where

David Makinson; Leendert van der Torre

2001-01-01

386

Dynamic Control of Cardiac Alternans  

NASA Astrophysics Data System (ADS)

A dynamic control technique was used to suppress a cardiac arrhythmia called an alternans rhythm in a piece of dissected rabbit heart. Our control algorithm adapted to drifting system parameters, making it well suited for the control of physiological rhythms. Control of cardiac alternans rhythms may have important clinical implications since they often precede serious cardiac arrhythmias and are a harbinger of sudden cardiac death.

Hall, Kevin; Christini, David J.; Tremblay, Maurice; Collins, James J.; Glass, Leon; Billette, Jacques

1997-06-01

387

Penetrating Cardiac Injury: A Review  

PubMed Central

Cardiac injury presents a great challenge to the emergency resident because these injuries require urgent intervention to prevent death. Sometimes serious cardiac injury may manifest only subtle or occult symptoms or signs. As there is an epidemic of cardiac injuries in Kashmir valley due to problems of law and order, we herein present a review on management of such injuries. PMID:24829887

Lateef Wani, Mohd; Ahangar, Ab Gani; Wani, Shadab Nabi; Irshad, Ifat; Ul-Hassan, Nayeem

2012-01-01

388

Cardiac Response and Personality Organization  

ERIC Educational Resources Information Center

This study examines the level and variability of cardiac response during complex problem-solving and interposed rest periods and their differing relationships to estimates of personality integration on the Rorschach. Findings suggest cardiac variability may be a more differentiated measure than level of cardiac response. (Author)

Blatt, Sidney J.; Feirstein, Alan

1977-01-01

389

Cardiac Response of Elderly Adults to Normal Activities and Aerobic Walking  

Microsoft Academic Search

To assess the cardiac response of elderly adults, three sedentary men and six women (M = 68 years) with no known cardiovascular disease had their cardiac responses to activities done in a laboratory setting (walking, climbing stairs, carrying bags, shuffleboard); normal daily activities and aerobic walking (pace at 60% of the age-adjusted heart rate) were assessed by a 24-hour holter

Beverly L. Roberts; Robert Palmer

1996-01-01

390

A Decade of Short-Term Outcomes in Post-Cardiac Surgery Ventricular Assist Device Implantation Data From the Society of Thoracic Surgeons' National Cardiac Database  

Microsoft Academic Search

Background—Previous studies showed 75% mortality before hospital discharge in patients with a ventricular assist device (VAD) placed for post-cardiac surgery shock. We examined a large national clinical database to assess trends in the incidence of post-cardiac surgery shock requiring VAD implantation, survival rates, and risk factors for mortality. Methods and Results—We identified patients undergoing a VAD procedure after cardiac surgery

Adrian F. Hernandez; Joshua D. Grab; James S. Gammie; Sean M. O'Brien; Bradley G. Hammill; Joseph G. Rogers; Margarita T. Camacho; Mercedes K. Dullum; T. Bruce Ferguson; Eric D. Peterson

2010-01-01

391

Management of the pediatric patient after cardiac surgery.  

PubMed Central

The medical management of the child with congenital cardiac disease prior to and following cardiac surgery has made a substantial contribution to the improved morbidity and mortality attributed to surgical advances. This paper provides a framework for understanding the problems that arise in the perioperative period and a systematic approach, by organ system, to monitoring and management of these problems. The discussion is intended to be of general application, focusing on initial stabilization following surgery and the cardiorespiratory, renal, metabolic, hematologic, and neurologic alterations that result from surgery with cardiopulmonary bypass. An approach for the management of the low output state is also provided. Little attempt has been made to focus on problems unique to a specific type of cardiac disease or certain operative approaches. Rather, it is the contention that an understanding of general principles and an appreciation of the common problems will provide adequate preparation for those responsible for the care of the child. PMID:6375165

Lister, G.

1984-01-01

392

Cardiac troponin I as a marker for severity and prognosis of cardiac disease in dogs  

Microsoft Academic Search

The use of cardiac troponin I (cTnI) to assess the severity of disease and prognosis in 120 dogs presented for cardiac evaluation was analysed. cTnI concentrations were measured using a commercially available assay. Dogs were placed into three groups: group 1, cTnI?0.15ng\\/mL; group 2, cTnI 0.151–1.0ng\\/mL; group 3, cTnI>1.01ng\\/mL. Dogs in group 1 were significantly younger (P<0.0001) and had no

S. Fonfara; J. Loureiro; S. Swift; R. James; P. Cripps; J. Dukes-McEwan

2010-01-01

393

Impact of obesity and weight loss on cardiac performance and morphology in adults.  

PubMed

Obesity, particularly severe obesity is capable of producing hemodynamic alterations that predispose to changes in cardiac morphology and ventricular function. These include increased cardiac output, left ventricular hypertrophy and diastolic and systolic dysfunction of both ventricles. Facilitated by co-morbidities such as hypertension, the sleep apnea/obesity hypoventilation syndrome, and possibly certain neurohormonal and metabolic alterations, these abnormalities may predispose to left and right heart failure, a disorder known as obesity cardiomyopathy. PMID:24438730

Alpert, Martin A; Omran, Jad; Mehra, Ankit; Ardhanari, Sivakumar

2014-01-01

394