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1

Cardiac Output Assessed by Invasive and Minimally Invasive Techniques  

PubMed Central

Cardiac output (CO) measurement has long been considered essential to the assessment and guidance of therapeutic decisions in critically ill patients and for patients undergoing certain high-risk surgeries. Despite controversies, complications and inherent errors in measurement, pulmonary artery catheter (PAC) continuous and intermittent bolus techniques of CO measurement continue to be the gold standard. Newer techniques provide less invasive alternatives; however, currently available monitors are unable to provide central circulation pressures or true mixed venous saturations. Esophageal Doppler and pulse contour monitors can predict fluid responsiveness and have been shown to decrease postoperative morbidity. Many minimally invasive techniques continue to suffer from decreased accuracy and reliability under periods of hemodynamic instability, and so few have reached the level of interchangeability with the PAC.

Lee, Allison J.; Cohn, Jennifer Hochman; Ranasinghe, J. Sudharma

2011-01-01

2

Understanding cardiac output  

PubMed Central

Cardiac output is the amount of blood the heart pumps in 1 minute, and it is dependent on the heart rate, contractility, preload, and afterload. Understanding of the applicability and practical relevance of each of these four components is important when interpreting cardiac output values. In the present article, we use a simple analogy comparing cardiac output with the speed of a bicycle to help appreciate better the effects of various disease processes and interventions on cardiac output and its four components.

Vincent, Jean-Louis

2008-01-01

3

Health Technology Assessment Reports, 1989. Number 3. Cardiac Output by Electrical Bioimpedance.  

National Technical Information Service (NTIS)

Electrical bioimpedance is a method used to determine stroke volume and cardiac output from thoracic tissue resistance to an imposed alternating electric current. The tissue resistance is inversely related to the thoracic blood content. When thoracic bloo...

H. Handelsman

1989-01-01

4

[Noninvasive cardiac output determinations].  

PubMed

The thermodilution determination of cardiac output (CO) by pulmonary arterial catheterization is considered to be the gold standard. However, a diversity of complications associated with the insertion and use of a catheter has made for the design of CO-measuring devices in a mini- or noninvasive mode. This prospective controlled study has been conducted to compare various CO determination techniques by the shape of the arterial curve (ART), as shown by the use of a transesophageal Doppler ultrasonic sensor (TEDUS) determining the blood flow velocity in the descending thoracic aorta by the Fick's backward equation with partial CO2 recirculation, by measuring thoracic bioimpedance (Tbio) by bolus thermodilution as the reference method (CO BT). In all the study examined, the mean CO values are lower than those in the reference method. In addition, there was a wide scatter of the CO values calculated by alternative methods. The mean difference and its standard deviation are 1.27 +/- 2.26 (ART); 0.87 +/- 1.57 (TEDUS); 1.01 +/- 1.46 (Fick); and 1.46 +/- 1.70 (Tbio). The errors of the methods, as compared to CO BT have the following values: APT, 27% (24-31% conference interval (CI)); TEDUS, 19% (17-21% CI); Fick, 20% (19-22%); Tbio, 25% (22-27%). By taking into account the findings, it should be stated that there is not any accurate mini- or noninvasive CO determination method that could completely substitute for the classical thermodilution technique. PMID:18051495

Subbotin, V V; Sitnikov, A V; Il'in, S A; Ovezov, A M; Chernogaeva, N V

2007-01-01

5

In vivo validation of cardiac output assessment in non-standard 3D echocardiographic images  

NASA Astrophysics Data System (ADS)

Automatic segmentation of the endocardial surface in three-dimensional (3D) echocardiographic images is an important tool to assess left ventricular (LV) geometry and cardiac output (CO). The presence of speckle noise as well as the nonisotropic characteristics of the myocardium impose strong demands on the segmentation algorithm. In the analysis of normal heart geometries of standardized (apical) views, it is advantageous to incorporate a priori knowledge about the shape and appearance of the heart. In contrast, when analyzing abnormal heart geometries, for example in children with congenital malformations, this a priori knowledge about the shape and anatomy of the LV might induce erroneous segmentation results. This study describes a fully automated segmentation method for the analysis of non-standard echocardiographic images, without making strong assumptions on the shape and appearance of the heart. The method was validated in vivo in a piglet model. Real-time 3D echocardiographic image sequences of five piglets were acquired in radiofrequency (rf) format. These ECG-gated full volume images were acquired intra-operatively in a non-standard view. Cardiac blood flow was measured simultaneously by an ultrasound transit time flow probe positioned around the common pulmonary artery. Three-dimensional adaptive filtering using the characteristics of speckle was performed on the demodulated rf data to reduce the influence of speckle noise and to optimize the distinction between blood and myocardium. A gradient-based 3D deformable simplex mesh was then used to segment the endocardial surface. A gradient and a speed force were included as external forces of the model. To balance data fitting and mesh regularity, one fixed set of weighting parameters of internal, gradient and speed forces was used for all data sets. End-diastolic and end-systolic volumes were computed from the segmented endocardial surface. The cardiac output derived from this automatic segmentation was validated quantitatively by comparing it with the CO values measured from the volume flow in the pulmonary artery. Relative bias varied between 0 and -17%, where the nominal accuracy of the flow meter is in the order of 10%. Assuming the CO measurements from the flow probe as a gold standard, excellent correlation (r = 0.99) was observed with the CO estimates obtained from image segmentation.

Nillesen, M. M.; Lopata, R. G. P.; de Boode, W. P.; Gerrits, I. H.; Huisman, H. J.; Thijssen, J. M.; Kapusta, L.; de Korte, C. L.

2009-04-01

6

In vivo validation of cardiac output assessment in non-standard 3D echocardiographic images.  

PubMed

Automatic segmentation of the endocardial surface in three-dimensional (3D) echocardiographic images is an important tool to assess left ventricular (LV) geometry and cardiac output (CO). The presence of speckle noise as well as the nonisotropic characteristics of the myocardium impose strong demands on the segmentation algorithm. In the analysis of normal heart geometries of standardized (apical) views, it is advantageous to incorporate a priori knowledge about the shape and appearance of the heart. In contrast, when analyzing abnormal heart geometries, for example in children with congenital malformations, this a priori knowledge about the shape and anatomy of the LV might induce erroneous segmentation results. This study describes a fully automated segmentation method for the analysis of non-standard echocardiographic images, without making strong assumptions on the shape and appearance of the heart. The method was validated in vivo in a piglet model. Real-time 3D echocardiographic image sequences of five piglets were acquired in radiofrequency (rf) format. These ECG-gated full volume images were acquired intra-operatively in a non-standard view. Cardiac blood flow was measured simultaneously by an ultrasound transit time flow probe positioned around the common pulmonary artery. Three-dimensional adaptive filtering using the characteristics of speckle was performed on the demodulated rf data to reduce the influence of speckle noise and to optimize the distinction between blood and myocardium. A gradient-based 3D deformable simplex mesh was then used to segment the endocardial surface. A gradient and a speed force were included as external forces of the model. To balance data fitting and mesh regularity, one fixed set of weighting parameters of internal, gradient and speed forces was used for all data sets. End-diastolic and end-systolic volumes were computed from the segmented endocardial surface. The cardiac output derived from this automatic segmentation was validated quantitatively by comparing it with the CO values measured from the volume flow in the pulmonary artery. Relative bias varied between 0 and -17%, where the nominal accuracy of the flow meter is in the order of 10%. Assuming the CO measurements from the flow probe as a gold standard, excellent correlation (r = 0.99) was observed with the CO estimates obtained from image segmentation. PMID:19265202

Nillesen, M M; Lopata, R G P; de Boode, W P; Gerrits, I H; Huisman, H J; Thijssen, J M; Kapusta, L; de Korte, C L

2009-04-01

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

Cardiac output: a view from Buffalo  

Microsoft Academic Search

Cardiac output ( Q?) is a primary determinant of blood pressure and O 2 delivery and is critical in the maintenance of homeostasis, particularly during environmental stress. Cardiac output can be determined invasively in patients; however, indirect methods are required for other situations. Soluble gas techniques are widely used to determine Q?. Historically, measurements during a breathhold, prolonged expiration and

A. J. Olszowka; B. E. Shykoff; D. R. Pendergast; C. E. G. Lundgren; L. E. Farhi

2003-01-01

10

Non-invasive assessment of cardiac output during exercise in chronic obstructive pulmonary disease: comparison of the -rebreathing method and electrical impedance cardiography  

Microsoft Academic Search

In exercise testing of patients with chronic obstructive pulmonary disease (COPD), non-invasive assessment of stroke volume (SV) and cardiac output (CO) would be valuable. Electrical impedance cardiography (EIC) has proved to be a valid and reliable instrument in healthy subjects. In this study it is investigated whether this also applies to patients with COPD. In 19 COPD patients simultaneous SV

H J Bogaard; W B G J Hamersma; J L M I Horsch; H H Woltjer; P E Postmus; P M J M de Vries

1997-01-01

11

Determination of Cardiac Output by the Fick Method, Thermodilution, and Acetylene Rebreathing in Pulmonary Hypertension  

Microsoft Academic Search

Assessment of cardiac output is an important part of the management of patients with pulmonary hypertension. The accuracy of the thermodilution technique in patients with low cardiac output or severe tricuspid regurgitation has been questioned. To address this issue, we simultaneously com- pared 105 cardiac output measurements by the Fick method and thermodilution in 35 patients with pulmonary hypertension. Moreover,

MARIUS M. HOEPER; ROMAN MAIER; JOERN TONGERS; JOST NIEDERMEYER; JENS M. HOHLFELD; MICHAEL HAMM; HELMUT FABEL

1999-01-01

12

A Review of Intraoperative Goal-Directed Therapy Using Arterial Waveform Analysis for Assessment of Cardiac Output  

PubMed Central

Increasing evidence shows that goal-directed hemodynamic management can improve outcomes in surgical and intensive care settings. Arterial waveform analysis is one of the different techniques used for guiding goal-directed therapy. Multiple proprietary systems have developed algorithms for obtaining cardiac output from an arterial waveform, including the FloTrac, LiDCO, and PiCCO systems. These systems vary in terms of how they analyze the arterial pressure waveform as well as their requirements for invasive line placement and calibration. Although small-scale clinical trials using these monitors show promising data, large-scale multicenter trials are still needed to better determine how intraoperative goal-directed therapy with arterial waveform analysis can improve patient outcomes. This review provides a comparative analysis of the different arterial waveform monitors for intraoperative goal-directed therapy.

Fernandez-Bustamante, Ana

2014-01-01

13

Evaluation of noninvasive cardiac output methods during exercise  

NASA Technical Reports Server (NTRS)

Noninvasive techniques to estimate cardiac output (Qc) will be used during future space flight. This retrospective literature survey compared the Qc techniques of carbon dioxide rebreathing (CO2-R), CO2 single breath (CO2-S), Doppler (DOP), impedance (IM), and inert gas (IG: acetylene or nitrous oxide) to direct (DIR) assessments measured at rest and during exercise.

Moore, Alan D.; Barrows, Linda H.; Rashid, Michael; Siconolfi, Steven F.

1992-01-01

14

Method of assessing the reproducibility of blood flow measurement: factors influencing the performance of thermodilution cardiac output computers.  

PubMed Central

Measurements of blood flow by three different makes of thermodilution cardiac output computer in an artificial circulation were analysed by linear regression against absolute flow measured by timed blood volume collection. For each computer the horizontal distance between the 95% confidence limits for a single prediction was calculated at a standard flow rate of 5 litres per minute. This measurement represents the range of flow rates that could give rise to an identical measurement and provides a summary of the reproducibility of the computer's results and its ability to detect a change of flow rate. This measurement was used to evaluate the effect on each computer's performance of pulsatile or continuous flow, injectate volume, and injectate temperature. With continuous flow the optimum results were 1.8, 0.85, and 0.85 litres per minute and with pulsatile flow they were 1.3, 1.05, and 1.65 litres per minute. There was generally a deterioration in performance when pulsatile flow was evaluated. Under the conditions of the experiment optimum performance in both flow modes was obtained with 5 ml of ice cold injectate, but these findings cannot necessarily be extrapolated to the clinical situation. With pulsatile flow the overall range of blood flows that could give rise to identical measurements were for each computer 2.0, 1.5, and 3.1 litres per minute, corresponding to 40, 30, and 62% changes of the standard flow rate of 5 litres per minute.

Mackenzie, J D; Haites, N E; Rawles, J M

1986-01-01

15

Non-Invasive Measurement of Cardiac Output during Atrial Fibrillation: Comparison between Cardiac Magnetic Resonance Imaging and Inert Gas Rebreathing  

Microsoft Academic Search

Objectives: Atrial fibrillation (AF) is one of the most frequent heart rhythm disorders. It potentially influences cardiac function and its measurement. Cardiac magnetic resonance imaging (CMR) has become the new gold standard for non-invasive assessment of cardiac output (CO). A novel inert gas rebreathing (IGR) device based on the Fick Principle also proved promising in patients in sinus rhythm (SR).

J. Saur; F. Trinkmann; C. Doesch; J. Weissmann; K. Hamm; S. O. Schoenberg; M. Borggrefe; D. Haghi; J. J. Kaden

2010-01-01

16

Cardiac Risk Assessment  

MedlinePLUS

... website will be limited. Search Help? Cardiac Risk Assessment Share this page: Was this page helpful? Formal ... Questions | Related Pages What is a cardiac risk assessment? This is a group of tests and health ...

17

Comparison of cardiac output determined by an ultrasound velocity dilution cardiac output method and by the lithium dilution cardiac output method in juvenile horses with experimentally induced hypovolemia.  

PubMed

Objective-To assess the accuracy of an ultrasound velocity dilution cardiac output (UDCO) method, compared with that of the lithium dilution cardiac output (LiDCO) method, for determination of cardiac output (CO) in juvenile horses with experimentally induced hypovolemia. Animals-12 anesthetized 2- to 6-month-old horses. Procedures-For each anesthetized horse, CO was determined by the LiDCO and UDCO methods prior to any intervention (baseline state), after withdrawal of approximately 40% of the horse's blood volume (low CO state), after maintenance of hypovolemia and infusion of norepinephrine until mean arterial blood pressure was equal to baseline value (high CO state), and after further infusion of norepinephrine and back-transfusion of withdrawn blood (posttransfusion state). For each of the 4 hemodynamic situations, CO and calculated cardiac index (CI) values were obtained by each method in duplicate (8 pairs of measurements/horse); mean values for each horse and overall mean values across all horses were calculated. Agreement between CI determined by each method (96 paired values) was assessed by Bland-Altman analysis. Results-For the UDCO method-derived CI measurements among the 12 horses, mean ± SD bias was -4 ± 11.3 mL/kg/min (95% limits of agreement, -26.1 to 18.2 mL/kg/min) and mean relative bias was -10.4 ± 21.5% (95% limits of agreement, -52.6% to 31.8%). Conclusions and Clinical Relevance-Results indicated that, compared with the LiDCO method, the UDCO method has acceptable clinical usefulness for determination of CO in foals. PMID:24866512

Shih, Andre C; Queiroz, Patricia; Vigani, Alessio; Da Cunha, Anderson; Pariaut, Romain; Ricco, Carolina; Bornkamp, Jennifer; Garcia-Pereira, Fernando; Bandt, Carsten

2014-06-01

18

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

19

Continuous wave doppler cardiac output: Use in pediatric patients receiving inotropic support  

Microsoft Academic Search

Summary Doppler estimates of cardiac output have been shown to correlate closely with invasive measurement of cardiac output in hemodynamically stable adults and children. However, this method has not been validated in hemodynamically unstable pediatric patients. To assess the accuracy of continuous wave Doppler echocardiography in pediatric patients with unstable hemodynamics, we performed 27 simultaneous Doppler and thermodilution comparisons in

William R. Morrow; Daniel J. Murphy; David J. Fisher; James C. Huhta; Larry S. Jefferson; E. O'Brian Smith

1988-01-01

20

A comparative evaluation of thermodilution and partial CO 2 rebreathing techniques for cardiac output assessment in critically ill patients during assisted ventilation  

Microsoft Academic Search

Objective To evaluate the reliability and clinical value of partial noninvasive CO 2 (NICO 2) rebreathing technique for measuring cardiac output compared with standard thermodilution in a group of intensive care nonpostoperative patients. Design and setting Clinical investigation in a university hospital ICU. Patients Twelve mechanically ventilated patients with high ( n=6) and low ( n=6) pulmonary shunt fractions. Measurements

Monica Rocco; Gustavo Spadetta; Andrea Morelli; Donatella Dell’Utri; Patrizia Porzi; Giorgio Conti; Paolo Pietropaoli

2004-01-01

21

Role of cardiac output in mediating arterial blood pressure oscillations.  

PubMed

The objective of this study was to determine the role of cardiac output in mediating spontaneous fluctuations in mean arterial pressure (MAP) conscious dogs. Dogs were chronically instrumented to monitor MAP and cardiac output. Atrioventricular (AV) block was induced, and left ventricular and right atrial electrodes were implanted. After recovery, MAP was observed for 5 min under two conditions: 1) normal variation in heart rate and cardiac output via triggering the ventricular stimulator with each atrial depolarization (effectively reversing the AV block, AV-linked stimulation) and 2) computer control of ventricular rate to maintain cardiac output constant on a by-beat basis at the same level as observed during normal variations in heart rate and cardiac output. When cardiac output was held constant, large-amplitude, low-frequency oscillations in MAP were readily apparent. Spectral analysis by fast Fourier transform revealed that during constant cardiac output the power observed at low frequencies in the MAP spectrum represented 95.0 +/- 2.7% of the total power compared with 75.5 +/- 4.6% during normal variations in heart rate and cardiac output (P < 0.05). In addition, when cardiac output was held constant, the power observed at higher frequencies markedly decreased from 24.5 +/- 4.6% of total power during AV-linked stimulation to only 5.0 +/- 2.7% of total power during constant cardiac output (P < 0.05). We conclude that low-frequency oscillations in MAP are due to changes in peripheral resistance, whereas a significant amount of high-frequency changes in MAP stems from spontaneous changes in cardiac output. PMID:8853386

O'Leary, D S; Woodbury, D J

1996-09-01

22

Predictors of low cardiac output syndrome after coronary artery bypass  

Microsoft Academic Search

The purpose of this study was to identify patients at risk for the development of low cardiac output syndrome after coronary artery bypass. Low cardiac output syndrome was defined as the need for postoperative intraaortic balloon pump or inotropic support for longer than 30 minutes in the intensive care unit to maintain the systolic blood pressure greater than 90 mm

Vivek Rao; Joan Ivanov; Richard D. Weisel; John S. Ikonomidis; George T. Christakis; Tirone E. David

1996-01-01

23

A Computer Learning Technique for Determining Cardiac Output.  

National Technical Information Service (NTIS)

The paper describes an automatic error-correcting algorithm for determining cardiac output from indicator-dilution curves. The importance of this technique, as opposed to existing methods, is that the use of error correction (also referred to as relaxatio...

R. Roy S. R. Powers

1970-01-01

24

Use of Dichromatic Earpiece Densitometry for Determination of Cardiac Output.  

National Technical Information Service (NTIS)

Dye-dilution curves were recorded simultaneously by a monochromatic earpiece densitometer, a dichromatic earpiece densitometer and a cuvette densitometer through which blood was sampled continuously from a radial artery. Comparison of cardiac output value...

J. H. Reed E. H. Wood

1964-01-01

25

Continuous cardiac output monitoring by peripheral blood pressure waveform analysis  

Microsoft Academic Search

We introduce a novel technique for continuously monitoring changes in cardiac output (CO) by mathematical analysis of a single peripheral arterial blood pressure (ABP) waveform. In contrast to all previous techniques, our technique analyzes ABP variations over time scales greater than a cardiac cycle in which wave reflections are attenuated. To validate the technique, we performed six swine experiments in

R. Mukkamala; A. T. Reisner; H. M. Hojman; Roger G. Mark; Richard J. Cohen

2003-01-01

26

Relation of QRS Shortening to Cardiac Output During Temporary Resynchronization Therapy after Cardiac Surgery  

PubMed Central

Cardiac resynchronization therapy (CRT) can improve cardiac function in heart failure without increasing myocardial oxygen consumption. However, CRT optimization based on hemodynamics or echocardiography is difficult. QRS duration (QRSd) is a possible alternative optimization parameter. Accordingly, we assessed QRSd optimization of CRT during cardiac surgery. We hypothesized that QRSd shortening during changes in interventricular pacing delay (VVD) would increase cardiac output (CO). Seven patients undergoing coronary artery bypass, aortic or mitral valve surgery with LV ejection fraction ? 40% and QRSd ? 100 msec were studied. CRT was implemented at epicardial pacing sites in the left and right ventricle and right atrium during VVD variation after cardiopulmonary bypass. QRSd was correlated with CO from an electromagnetic aortic flow probe. Both positive and negative correlations were observed. Correlation coefficients ranged from 0.70 to ?0.74 during VVD testing. Clear minima in QRSd were observed in four patients and were within 40 msec of maximum CO in two. We conclude that QRSd is not useful for routine optimization of VVD after cardiac surgery but may be useful in selected patients. Decreasing QRSd is associated with decreasing CO in some patients, suggesting that CRT can affect determinants of QRSd and ventricular function independently.

Spotnitz, Matthew E.; Richmond, Marc E.; Quinn, T. Alexander; Cabreriza, Santos E.; Wang, Daniel Y.; Albright, Catherine M.; Weinberg, Alan D.; Dizon, Jose M.; Spotnitz, Henry M.

2011-01-01

27

Evaluation of heavy water for indicator dilution cardiac output measurement  

SciTech Connect

We evaluated deuterium oxide (D2O) as a tracer for cardiac output measurements. Cardiac output measurements made by thermodilution were compared with those made by indicator dilution with D2O and indocyanine green as tracers. Five triplicate measurements for each method were made at intervals of 30 minutes in each of 9 anesthetized, mechanically ventilated goats. Cardiac output ranged between 0.68 and 3.79 L/min. The 45 data points yielded a correlation coefficient of 0.948 for the comparison of D2O indicator dilution cardiac output measurements with thermodilution measurements and a linear regression slope of 1.046. D2O indicator dilution measurements were biased by -0.11 +/- 0.22 L/min compared with thermodilution measurements and had a standard deviation of +/- 0.12 L/min for triplicate measurements. Hematocrits ranging between 20 and 50 vol% had no effect on optical density for D2O. D2O is more stable than indocyanine green and approximately one-tenth the price (40 cents per injection compared with $4). The basic instrumentation cost of approximately $9,000 is an additional initial expense, but provides the ability to perform pulmonary extravascular water measurements with a double-indicator dilution technique. D2O has potential as a tracer for the clinical determination of indicator dilution cardiac output measurements and pulmonary extravascular water measurements.

Schreiner, M.S.; Leksell, L.G.; Neufeld, G.R. (Univ. of Pennsylvania School of Medicine, Philadelphia (USA))

1989-10-01

28

Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients.  

PubMed

The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy and other existing measurements, creating a CO measure without further invasiveness.This paper examines combining models of diffusion resistance and lung mechanics, to help predict CO changes due to PEEP. The CO estimator uses an initial measurement of pulmonary shunt, and estimations of shunt changes due to PEEP to predict CO at different levels of PEEP. Inputs to the cardiac model are the PV loops from the ventilator, as well as the oxygen saturation values using known respiratory inspired oxygen content. The outputs are estimates of pulmonary shunt and CO changes due to changes in applied PEEP. Data from two published studies are used to assess and initially validate this model.The model shows the effect on oxygenation due to decreased CO and decreased shunt, resulting from increased PEEP. It concludes that there is a trade off on oxygenation parameters. More clinically importantly, the model also examines how the rate of CO drop with increased PEEP can be used as a method to determine optimal PEEP, which may be used to optimise MV therapy with respect to the gas exchange achieved, as well as accounting for the impact on the cardiovascular system and its management. PMID:21108836

Sundaresan, Ashwath; Chase, J Geoffrey; Hann, Christopher E; Shaw, Geoffrey M

2010-01-01

29

Cardiac Output Derived from Arterial Pressure Waveform Analysis in Patients Undergoing Cardiac Surgery: Validity of a Second Generation Device  

Microsoft Academic Search

BACKGROUND: The performance of a recently introduced, arterial waveform-based device for measuring cardiac output (CO) without the need of invasive calibration (FloTrac\\/Vigileo™) has been controversial. We designed the present study to assess the validity of an improved version of this monitoring technique compared with intermittent thermodilution CO measurement using a pulmonary artery catheter in patients undergoing cardiac surgery. METHODS: Forty

Jochen Mayer; Joachim Boldt; Michael W. Wolf; Johannes Lang; Stefan Suttner

2008-01-01

30

Pulse contour cardiac output derived from non-invasive arterial pressure in cardiovascular disease.  

PubMed

Pulse contour methods determine cardiac output semi-invasively using standard arterial access. This study assessed whether cardiac output can be determined non-invasively by replacing the intra-arterial pressure input with a non-invasive finger arterial pressure input in two methods, Nexfin CO-trek and Modelflow , in 25 awake patients after coronary artery bypass surgery. Pulmonary artery thermodilution cardiac output served as a reference. In the supine position, the mean (SD) differences between thermodilution cardiac output and Nexfin CO-trek were 0.22 (0.77) and 0.44 (0.81) l.min(-1) , for intra-arterial and non-invasive pressures, respectively. For Modelflow, these differences were 0.70 (1.08) and 1.80 (1.59) l.min(-1) , respectively. Similarly, in the sitting position, differences between thermodilution cardiac output and Nexfin CO-trek were 0.16 (0.78) and 0.34 (0.83), for intra-arterial and non-invasive arterial pressure, respectively. For Modelflow, these differences were 0.58 (1.11) and 1.52 (1.54) l.min(-1) , respectively. Thus, Nexfin CO-trek readings were not different from thermodilution cardiac output, for both invasive and non-invasive inputs. However, Modelflow readings differed greatly from thermodilution when using non-invasive arterial pressure input. PMID:20860647

Bogert, L W J; Wesseling, K H; Schraa, O; Van Lieshout, E J; de Mol, B A J M; van Goudoever, J; Westerhof, B E; van Lieshout, J J

2010-11-01

31

Model for Non-invasive Cardiac Output Measurement  

Microsoft Academic Search

Aim of the presented work has been the development of an algorithm for a non-invasive, portable, easy to use, and affordable device for measuring systemic cardiovascular parameters like cardiac output and peripheral resistance. The data acquisition is based on a common oscillometric measurement using an occlusive blood pressure cuff and no additional calibration is necessary. The introduced novel algorithm combines

Siegfried Wassertheurer; Felix Breitenecker

2007-01-01

32

Continuous negative extrathoracic pressure and cardiac output —a pilot study  

Microsoft Academic Search

Continuous negative extrathoracic pressure (CNEP) has been recently reintroduced as therapy for respiratory failure. To determine its effects on cardiac output a pilot study was performed in ten patients aged 2 months-3 years (meadian 4 months). All had chronic respiratory failure (seven with bronchopulmonary dysplasia). Five were breathing spontaneously and five were intubated and undergoing intermittent positive pressure ventilation. Transcutaneous

J. Raine; A. N. Redington; A. Benatar; M. P. Samuels; D. P. Southall

1993-01-01

33

Continuous cardiac output monitoring by peripheral blood pressure waveform analysis  

Microsoft Academic Search

A clinical method for monitoring cardiac output (CO) should be continuous, minimally invasive, and accurate. However, none of the conventional CO measurement methods possess all of these characteristics. On the other hand, peripheral arterial blood pressure (ABP) may be measured reliably and continuously with little or no invasiveness. We have developed a novel technique for continuously monitoring changes in CO

Ramakrishna Mukkamala; Andrew T. Reisner; Horacio M. Hojman; Roger G. Mark; Richard J. Cohen

2006-01-01

34

Comparison of uncalibrated arterial waveform analysis in cardiac surgery patients with thermodilution cardiac output measurements  

Microsoft Academic Search

INTRODUCTION: Cardiac output (CO) monitoring is indicated only in selected patients. In cardiac surgical patients, perioperative haemodynamic management is often guided by CO measurement by pulmonary artery catheterisation (COPAC). Alternative strategies of CO determination have become increasingly accepted in clinical practice because the benefit of guiding therapy by data derived from the PAC remains to be proven and less invasive

Michael Sander; Claudia D Spies; Herko Grubitzsch; Achim Foer; Marcus Müller; Christian von Heymann

2006-01-01

35

Effect of atrioventricular synchronous pacing on cardiac output determined by CO 2 rebreathing at constant submaximal exercise  

Microsoft Academic Search

This study compared cardiac output assessed by a noninvasive CO2 rebreathing method at identical submaximal exercise and heart rate response in patients undergoing DDD or VVI pacing. Our results did not show any hemodynamic superiority of AV synchronous pacing.

Herve´ Douard; Catherine Blaquiere-Roche; Vincent Tourtoulou; Philippe Bordier; Jean Paul Broustet

1995-01-01

36

Evaluation of a noninvasive method for cardiac output measurement in critical care patients  

Microsoft Academic Search

Objective. Thermodilution (TD) is the gold standard to monitor cardiac output (CO) in critical care. However, there is concern about the safety of right-ventricular catheterization. The CO2 rebreathing technique allows noninvasive CO determination by means of the indirect Fick principle. Our objectives were: (a) to assess the accuracy of a new system of CO measurement using the CO2 partial rebreathing

Gastón E. Murias; Ana Villagrá; Sara Vatua; Maria del Mar Fernandez; Héctor Solar; Ana Ochagavía; Rafael Fernández; Josefina Aguilar; Pablo V. Romero; Lluis Blanch

2002-01-01

37

[Continuous measurement of cardiac output with pulse contour analysis].  

PubMed

Pulse contour cardiac output (PCCO) is an easily applicable method for continuous measurement of cardiac output in critically ill patients. Calculation of stroke volume is possible by analysing the area under the systolic part of the arterial pulse pressure waveform together with an individual calibration factor (Zao) to account for the individually variable vascular impedance. Since vascular impedance is potentially affected by altered vascular tone, it was the aim of the present study to examine the validity of PCCO in ICU patients receiving various dosages of a variety of vasoactive drugs. PATIENTS AND METHODS. Continuous cardiac output was measured in 20 ICU patients for a total of 110 h using the pulse contour method. The precision of PCCO was determined in comparison with its calibration reference, the thermodilution method (TDCO): (1) during administration of vasoactive drugs at a constant rate and (2) during conditions with altered vascular tone and haemodynamics elicited by changes in vasoactive drug dosage. For this purpose, the patients received varying dosages of vasoactive drugs (dopamine, dobutamine, epinephrine, norepinephrine, nitroglycerin, prostacyclin and urapidil). RESULTS. A total of 165 data sets was obtained, each consisting of the average of four capnometrically triggered TDCO measurements and the corresponding PCCO values. The relative difference between methods (+/- 2 SD) was +/- 23.9% (SD 0.85 l.min-1; r = 0.93) if a single calibration at the beginning of measurement series was performed (Fig. 2). The bias of the mean cardiac output values of both methods was -0.09 l.min-1. The precision of PCCO improved to +/- 15.7% by additional calibrations (SD 0.56.min-1; r = 0.96; bias 0.003 l.min-1). Data of two patients showed that recalibration may be necessary after extreme haemodynamic changes due to septic shock or cooling. Alteration of vascular tone by clinically used dosage of vasoactive drugs, however, had no destabilizing effect on the pulse contour method. CONCLUSIONS. It could be demonstrated that PCCO provides a valuable method for continuous cardiac output measurement in the intensive care setting with a precision comparable to that of thermodilution. PMID:7661336

Irlbeck, M; Forst, H; Briegel, J; Haller, M; Peter, K

1995-07-01

38

Noninvasive Determination of Cardiac Output by the Inert-Gas-Rebreathing Method – Comparison with Cardiovascular Magnetic Resonance Imaging  

Microsoft Academic Search

Background: An easy, noninvasive and accurate technique for measuring cardiac output (CO) would be desirable for the diagnosis and therapy of cardiac diseases. Innocor, a novel inert-gas-rebreathing (IGR) system, has shown promising results in smaller studies. An extensive evaluation in a larger, less homogeneous patient collective is lacking. Methods: We prospectively assessed the accuracy and reproducibility of CO measurements obtained

Joachim Saur; Stephan Fluechter; Frederik Trinkmann; Theano Papavassiliu; Stefan Schoenberg; Joerg Weissmann; Dariusch Haghi; Martin Borggrefe; Jens J. Kaden

2009-01-01

39

Arteriovenous fistula-associated high-output cardiac failure: a review of mechanisms  

Microsoft Academic Search

High-output cardiac failure can be a rare complication of high-output arterioveous fistula. The authors present a case in which a hemodialysis patient with a high-flow arteriovenous fistula has cardiac failure that improves with fistula closure. The hemodynamic effects of a fistula are reviewed, and the hemodialysis literature regarding high-output cardiac failure is summarized. To gain insight into the problem of

Jennifer M MacRae; Sanjay Pandeya; Dennis P Humen; Nikolai Krivitski; Robert M Lindsay

2004-01-01

40

Partial CO2 Rebreathing Indirect Fick Technique for Non-Invasive Measurement of Cardiac Output  

Microsoft Academic Search

Objective.Evaluation in animals of a non-invasive and continuous cardiac output monitoring system based on partial carbon-dioxide (CO2) rebreathing indirect Fick technique. Methods.We have developed a non-invasive cardiac output (NICO) monitoring system, based on the partial rebreathing method. The partial\\u000a rebreathing technique employs a differential form of the Fick equation for calculating cardiac output (QT) using non-invasive measurements. Changes in CO2

Dinesh G. Haryadi; Joseph A. Orr; Kai Kuck; Scott McJames; Dwayne R. Westenskow

2000-01-01

41

Comparison of methods to calculate cardiac output using the CO 2 rebreathing method  

Microsoft Academic Search

Summary  A comparison was made of methods used to calculate cardiac output by the indirect (CO2) Fick procedure (equilibrium method). Alternative methods for calculation of arterialPCO2, mixed venousPCO2, and conversion of gas tension to content were tested. Cardiac output values determined with a “corrected” equilibriumPCO2, to approximate mixed venousPCO2, were observed to be closest to cardiac output values determined on similar

Donald H. Paterson; David A. Cunningham

1976-01-01

42

Continuous cardiac output monitoring by peripheral blood pressure waveform analysis.  

PubMed

A clinical method for monitoring cardiac output (CO) should be continuous, minimally invasive, and accurate. However, none of the conventional CO measurement methods possess all of these characteristics. On the other hand, peripheral arterial blood pressure (ABP) may be measured reliably and continuously with little or no invasiveness. We have developed a novel technique for continuously monitoring changes in CO by mathematical analysis of a peripheral ABP waveform. In contrast to the previous techniques, our technique analyzes the ABP waveform over time scales greater than a cardiac cycle in which the confounding effects of complex wave reflections are attenuated. The technique specifically analyzes 6-min intervals of ABP to estimate the pure exponential pressure decay that would eventually result if pulsatile activity abruptly ceased (i.e., after the high frequency wave reflections vanish). The technique then determines the time constant of this exponential decay, which equals the product of the total peripheral resistance and the nearly constant arterial compliance, and computes proportional CO via Ohm's law. To validate the technique, we performed six acute swine experiments in which peripheral ABP waveforms and aortic flow probe CO were simultaneously measured over a wide physiologic range. We report an overall CO error of 14.6%. PMID:16532772

Mukkamala, Ramakrishna; Reisner, Andrew T; Hojman, Horacio M; Mark, Roger G; Cohen, Richard J

2006-03-01

43

Regional blood flow distribution in dog during induced hypotension and low cardiac output. Spontaneous breathing versus artificial ventilation.  

PubMed Central

Respiratory muscle blood flow and organ blood flow was studied in two groups of dogs with radioactively labeled microspheres to assess the influence of the working respiratory muscles on the regional distribution of blood flow when arterial pressure and cardiac output were lowered by pericardial tamponade. In one group (n = 6), the dogs were paralyzed and mechanically ventilated (Mv), while in the other (n = 6), they were left to breathe spontaneously (Sb). Cardiac output fell to 30% of control values during tamponade in both groups and was maintained constant. None of the dogs was hypoxic. Ventilation in the Sb group peaked after 50 min of hypotension, but remained unchanged in the Mv group. Duplicate measurements of blood flow were made during a control period and after 50 min of tamponade (corresponding to the peak ventilation in Sb). Blood flow to the respiratory muscles increased significantly (P less than 0.001) during tamponade in Sb (diaphragmatic flow increased to 361% of control values), while it decreased in Mv. Although the arterial blood pressure and cardiac output were comparable in the two groups, blood flow distribution during tamponade was different. In Sb, the respiratory muscles received 21% of the cardiac output, compared with only 3% in the Mv group. Thus, by muscle paralysis and Mv, a large fraction of the cardiac output used by the working respiratory muscles can be made available for perfusion of other organs during low cardiac output state: blood flows to the liver, brain, and quadriceps muscles were significantly higher during tamponade in the Mv group compared with the Sb group. Similarly, blood lactate at all times after the induction of low cardiac output and hypotension was significantly lower in the Mv animals (P less than 0.005).

Viires, N; Sillye, G; Aubier, M; Rassidakis, A; Roussos, C

1983-01-01

44

Non-invasive cardiac output monitoring during catheter interventions in patients with cavopulmonary circulations.  

PubMed

Introduction: Functionally univentricular hearts palliated with superior or total cavopulmonary connection result in circulations in series. The absence of a pre-pulmonary pump means that cardiac output is more difficult to adjust and control. Continuous monitoring of cardiac output is crucial during cardiac catheter interventions and can provide new insights into the complex physiology of these lesions. Materials and methods: The Icon® cardiac output monitor was used to study the changes in cardiac output during catheter interventions in 15 patients (median age: 6.1 years, range: 4.8-15.3 years; median weight: 18.5 kg, range: 15-63 kg) with cavopulmonary circulations. A total of 19 interventions were undertaken in these patients and the observed changes in cardiac output were recorded and analysed. Results: Cardiac output was increased with creation of stent fenestrations after total cavopulmonary connection (median increase of 22.2, range: 6.7%-28.6%) and also with drainage of significant pleural effusions (16.7% increase). Cardiac output was decreased with complete or partial occlusion of fenestrations (median decrease of 10.6, range: 7.1%-13.4%). There was a consistent increase in cardiac output with stenting of obstructive left pulmonary artery lesions (median increase of 7.7, range: 5%-14.3%, p = 0.007). Conclusions: Icon® provides a novel technique for the continuous, non-invasive monitoring of cardiac output. It provides a further adjunct for monitoring of physiologically complex patients during catheter interventions. These results are consistent with previously reported series involving manipulation of fenestrations. This is the first report identifying an increase in cardiac output with stenting of obstructive pulmonary arterial lesions. PMID:23680531

Noonan, Patrick Michael Emmet; Viswanathan, Sangeetha; Chambers, Amy; Stumper, Oliver

2014-06-01

45

Continuous cardiac output measurement: pulse contour analysis vs thermodilution technique in cardiac surgical patients.  

PubMed

We have analysed the clinical agreement between two methods of continuous cardiac output measurement pulse contour analysis (PCCO) and a continuous thermodilution technique (CCO), were both compared with the intermittent bolus thermodilution technique (BCO). Measurements were performed in 26 cardiac surgical patients (groups 1 and 2, 13 patients each, with an ejection fraction > 45% and < 45%, respectively) at 12 selected times. During operation, mean differences (bias) between PCCO-BCO and CCO-BCO did not differ in either group. However, phenylephrine-induced increases in systemic vascular resistance (SVR) by approximately 60% resulted in significant differences. Significantly higher absolute bias values of PCCO-BCO compared with CCO-BCO were also found early after operation in the ICU. Thus PCCO and CCO provided comparable measurements during coronary bypass surgery. After marked changes in SVR, further calibration of the PCCO device is necessary. PMID:10472216

Rödig, G; Prasser, C; Keyl, C; Liebold, A; Hobbhahn, J

1999-04-01

46

Thermodynamics of the heart: Relation between cardiac output and oxygen consumption  

NASA Astrophysics Data System (ADS)

A thermodynamic approach is used to derive a relation between cardiac output and rate of oxygen consumption. As an example, the relation is used to calculate the cardiac output of a young woman exercising on a treadmill. The results can be understood by undergraduates without any previous knowledge of human physiology.

Uehara, Mituo; Sakane, Kumiko K.; Bertolotti, Simone A.

2008-06-01

47

An experimental, simplified method for intradialytic cardiac output measurement.  

PubMed

Hypotension during hemodialysis (HD) is a frequent and troublesome treatment complication. A decrease in the cardiac output (CO) due to an imbalance in the rates of fluid ultrafiltration vs. tissue reabsorption is a major cause of such episodes; thus, routine repeated measurements of CO during HD sessions could be of use in preventing its occurrence. We tested an experimental method (EXP) for measuring CO during HD using hardware already supplied with current Gambro dialysis machines. In 12 HD patients, CO was measured twice during dialysis by injecting a small (2?mL) bolus of highly concentrated saline into the patient's bloodstream and measuring the subsequent increase in dialysate conductivity using the Diascan technology. CO was calculated with the Stewart-Hamilton method using the area under the conductivity curve, measured dialysate flow rate, and dialyzer clearance. Compared with ultrasound hemodilution measurements, the EXP showed no bias and limits of agreement of ±34.6%. The intradialytic trend correlated well between the two methods (r(2) ?=?0.63, concordance rate 100%). We propose that with further development and refining, reliable measurements of CO could be performed easily during routine HD treatment using this new methodology. PMID:22188038

Cordtz, Joakim; Sternby, Jan

2012-03-01

48

Cardiac output by arterial pulse contour: reliability under hemodynamic derangements.  

PubMed

Pulse contour methods (PCM) for the measurements of cardiac output (CO) are gaining popularity in intensive care settings but their reliability during hemodynamic instability has been questioned. Pressure-recording-analytical-method (PRAM) is a newly developed uncalibrated hemodynamic monitor and its capability in measuring CO during hemodynamic instability is still under investigation. Dobutamine (2.5 and 5 microg/kg/min), vasoconstriction (arginine-vasopressin 4, 8 and 16 IU/h), hemorrhage (-10%, -20%, -35%, and -50% of the theoretical volemia), and volume resuscitation were induced in eight swine. CO by means of thermodilution (CO(ThD)), transesophageal echocardiography (CO(TEE)) and PRAM (CO(PRAM)) were contemporarily registered. R(2), bias, and percentage error were used to compare the methods. Comparison between CO(PRAM) and CO(ThD) resulted in: r(2)=0.87; bias=-0.006 l/min; precision=+/-0.87 l/min; percentage error=22.8%. Comparison between CO(PRAM) and CO(TEE) resulted in: r(2)=0.85; bias=-0.007 l/min; precision=+/-0.86 l/min; percentage error=22%. Sub-group analysis revealed disagreement between methods only during the last two steps of hemorrhage: CO(PRAM) vs. CO(ThD): r(2)=0.67, bias=-0.37 l/min, precision=+/-1.04 l/min, limits of agreement=-1.39+0.66 l/min, and percentage error=45%; CO(PRAM) vs. CO(TEE): r(2)=0.38, bias=0.4 l/min, precision=+/-1.42 l/min, limits of agreement=-0.99+1.79 l/min, and percentage error=62%. PRAM resulted to be accurate in measuring CO during hemodynamic stability, tachycardia, and vasoconstriction. When volemia was reduced by >35%, disagreement between methods was observed. PMID:19299422

Romagnoli, Stefano; Romano, Salvatore Mario; Bevilacqua, Sergio; Ciappi, Francesco; Lazzeri, Chiara; Peris, Adriano; Dini, Daniele; Gelsomino, Sandro

2009-06-01

49

[Measurement of cardiac output by thermodilution with a diode as a temperature sensor].  

PubMed

An area integrator for the thermodilution curve in cardiac output measurement is described. A new temperature sensor is used, a diode with some advantages over the thermistor normally used. The main advantages are: easy calibration and replacement, and broad range of linearity. The cardiac output values obtained in dog with the integrator follow a linear relationship with those of the flowmeter. In simultaneous measurements the correlation is R = 0.96. Using a diode as temperature sensor a modification of the Steward Hamilton equation (used for thermistor) is necessary. With this new equation a monogram is performed to calculate the cardiac output from the area given by the numerical integrator. PMID:550124

Díaz Fernández, A; Benítez, D; Sánchez Tello, G; Márquez, L A

1979-01-01

50

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

PubMed Central

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.

Kang, Dongyel; Huang, Qiaojian; Li, Youzhi

2014-01-01

51

Application of ultrasound dilution technology for cardiac output measurement: Cerebral and systemic hemodynamic consequences in a juvenile animal model  

Microsoft Academic Search

OBJECTIVE: Analysis of cerebral and systemic hemodynamic consequences of ultrasound dilution cardiac output measurements. DESIGN: : Prospective, experimental piglet study. SETTING: Animal laboratory. SUBJECTS: Nine piglets. INTERVENTIONS: Ultrasound dilution cardiac output measurements were performed in ventilated, anesthetized piglets. Interventions that are required for ultrasound dilution cardiac output measurement were evaluated for its effect on cerebral and systemic circulation and oxygenation.

W. P. de Boode; A. F. J. van Heijst; J. C. W. Hopman; R. B. Tanke; J. G. van der Hoeven; K. D. Liem

2010-01-01

52

Comparison of dye dilution method to radionuclide techniques for cardiac output determination in dogs  

SciTech Connect

A study was undertaken to identify the most accurate /sup 99m/Tc-labeled radiopharmaceutical and to determine the accuracy of a noninvasive radionuclide technique or cardiac output determinations. Phase I employed sodium pertechnetate, stannous pyrophosphate with sodium pertechnetate, /sup 99m/Tc red blood cells, and /sup 99m/Tc human serum albumin as radionuclide tracers. Cardiac output was determined by the dye dilution method and then by the invasive radionuclide technique. A pairied t test and regression analysis indicated that /sup 99m/Tc human serum albumin was the most accurate radiopharmaceutical for cardiac output determinations, and the results compared favorably to those obtained by the dye dilution method. In Phase II, /sup 99m/Tc human serum albumin was used as the radionuclide tracer for cardiac output determinations with the noninvasive technique. The results compared favorably to those obtained by the dye dilution method.

Eng, S.S.; Robayo, J.R.; Porter, W.; Smith, R.E.

1980-05-01

53

Cardiac clinical skill assessments for registered nurses.  

PubMed

This article outlines a framework of clinical skill assessments that identify the knowledge and skills required for safe and competent care of cardiac patients. This framework categorizes identified cardiac skills into a logical sequence for assessment, aims to standardize the assessment process, and allows transportability of clinical skills. PMID:22449887

Boyde, Mary; Witt, Jane

2012-01-01

54

The thermal-dye method of lung water measurement is reliable at a low cardiac output.  

PubMed

The measurement of lung water by the thermal-dye double indicator dilution technique was evaluated in dogs with normal and edematous lungs during a state of reduced cardiac output. The technique used cold indocyanine green dye to measure extravascular thermal volume (EVTV) as an estimate of extravascular lung water (EVLW). Anesthesia was maintained with pentobarbital. In 15 of 21 animals, pulmonary edema was first induced with oleic acid (0.75 to 0.18 ml/kg). Cardiac output (CO) was then decreased by a combination of propranolol and slow exsanguination (mean CO reduction to 36% of baseline). Extravascular lung water produced in this model ranged from 1.4 to 30.2 ml/kg. Predetermination measurements of EVTV correlated closely with EVLW as determined by gravimetric analysis (EVTV = 1.1 EVLW + 4.7 ml/kg, n = 21, r = 0.93, P less than 0.001). Thermodilution cardiac output measured in the abdominal aorta (used in the calculation of the EVTV) correlated well with simultaneous measurements of cardiac output by both indocyanine green dye dilution and pulmonary artery thermodilution (r = 0.86 and r = 0.88, respectively, pretermination). The thermal-dye technique appears to provide an accurate reflection of lung water in normal and edematous lungs, even in the presence of a low cardiac output. PMID:3762135

Calcagni, D E; Mihm, F G; Feeley, T W; Halperin, B D; Rosenthal, M H

1986-09-01

55

Expiratory Loading Improves Cardiac Output During Exercise In Heart Failure  

PubMed Central

Purpose To investigate the effect of changes in expiratory intrathoracic pressure (ITP) on stroke volume (SV) at rest and during moderate exercise in patients with heart failure vs. healthy individuals. Methods SV was obtained by echocardiography during spontaneous breathing and during expiratory loads of 5 and 10 cm H2O produced by a ventilator in 11 patients with heart failure (61±9 years, EF: 32±4%, NYHA class I-II) and 11 age-matched healthy individuals at rest and during exercise at 60% of aerobic capacity on a semi-recumbent cycle ergometer. Results At rest, expiratory loading did not change heart rate, SV index (SVI) or cardiac index (CI) in either group. During moderate exercise, expiratory loading increased SVI and CI in patients with heart failure, but decreased SVI and CI in healthy individuals. There was a negative correlation between changes in gastric pressure and SVI (r=?0.51, p<0.05) in healthy individuals, while there was a positive correlation between changes in gastric pressure accompanying expiratory loading and CI (r=0.83, p<0.01) in patients with heart failure. Conclusion Expiratory loading during moderate exercise elicited increases in SVI and CI in patients with heart failure but decreased SVI and CI in healthy individuals. Improvements in cardiac function during submaximal exercise in patients with heart failure may be caused by a beneficial reduction in LV preload.

Lalande, Sophie; Luoma, Charles E.; Miller, Andrew D.; Johnson, Bruce D.

2012-01-01

56

Peak Cardiac Power Output, Measured Noninvasively, Is a Powerful Predictor of Outcome in Chronic Heart Failure  

Microsoft Academic Search

Background—The cardiac output (CO) response to exercise and other invasively derived hemodynamic variables has been variably described to provide better prognostication than peak VO2 in patients with chronic heart failure. Using noninvasive measurements of CO during exercise, we compared the prognostic value of peak CO and cardiac power to peak VO2 in chronic heart failure patients. Method and Results—One hundred

Chim C. Lang; Paula Karlin; Jennifer Haythe; Tiong K. Lim; Donna M. Mancini

2010-01-01

57

Decreased cardiac output, venous congestion and the association with renal impairment in patients with cardiac dysfunction  

Microsoft Academic Search

Background: Renalfailureinheartfailureisrelatedtodecreasedcardiacoutput.However,littleisknownaboutitsassociationwithvenouscongestion. Aims: To investigate the relationship between venous congestion and glomerular filtration rate (GFR) in patients with cardiac dysfunction. Methods and results: Right atrial pressure (RAP) and cardiac index (CI) were determined by right heart catheterisation in 51 patients with cardiac dysfunction, secondary to pulmonary hypertension. GFR and renal blood flow (RBF) were measured as 125I-Iothalamate and 131I- Hippuran

Kevin Damman; Gerjan Navis; Tom D. J. Smilde; Adriaan A. Voors; Wim van der Bij; Dirk J. van Veldhuisen; Hans L. Hillege

2007-01-01

58

Cardiac output and sympathetic vasoconstrictor responses during upright tilt to presyncope in healthy humans.  

PubMed

Syncope is a common clinical condition occurring even in healthy people without manifest cardiovascular disease. The purpose of this study was to determine the role of cardiac output and sympathetic vasoconstriction in neurally mediated (pre)syncope. Twenty-five subjects (age 15–51) with no history of recurrent syncope but who had presyncope during 60 deg upright tilt were studied; 10 matched controls who completed 45 min tilting were analysed retrospectively. Beat-to-beat haemodynamics (Modelflow), muscle sympathetic nerve activity (MSNA) and sympathetic baroreflex sensitivity (MSNA–diastolic pressure relation) were measured. MSNA, haemodynamic responses and baroreflex sensitivity during early tilting were not different between presyncopal subjects and controls. Hypotension was mediated by a drop in cardiac output in all presyncopal subjects, accompanied by a decrease in total peripheral resistance in 16 of them (64%, group A). In the other 9 subjects, total peripheral resistance was well maintained even at presyncope (36%, group B). Cardiac output was smaller (3.26 ± 0.34 (SEM) vs. 5.02 ± 0.40 l min(?1), P = 0.01), while total peripheral resistance was greater (1327 ± 117 vs. 903 ± 80 dyn s cm(?5), P < 0.01) in group B than group A at presyncope. The steeper fall in cardiac output in group B was due to a drop in heart rate. MSNA decreased rapidly at presyncope after the onset of hypotension. Thus, a moderate fall in cardiac output with coincident vasodilatation or a marked fall in cardiac output with no changes in peripheral vascular resistance may contribute to (pre)syncope. However, an intrinsic impairment of vasomotor responsiveness and sympathetic baroreflex function is not the cause of neurally mediated (pre)syncope in this population. PMID:22331415

Fu, Qi; Verheyden, Bart; Wieling, Wouter; Levine, Benjamin D

2012-04-15

59

Cardiac output and sympathetic vasoconstrictor responses during upright tilt to presyncope in healthy humans  

PubMed Central

Syncope is a common clinical condition occurring even in healthy people without manifest cardiovascular disease. The purpose of this study was to determine the role of cardiac output and sympathetic vasoconstriction in neurally mediated (pre)syncope. Twenty-five subjects (age 15–51) with no history of recurrent syncope but who had presyncope during 60 deg upright tilt were studied; 10 matched controls who completed 45 min tilting were analysed retrospectively. Beat-to-beat haemodynamics (Modelflow), muscle sympathetic nerve activity (MSNA) and sympathetic baroreflex sensitivity (MSNA–diastolic pressure relation) were measured. MSNA, haemodynamic responses and baroreflex sensitivity during early tilting were not different between presyncopal subjects and controls. Hypotension was mediated by a drop in cardiac output in all presyncopal subjects, accompanied by a decrease in total peripheral resistance in 16 of them (64%, group A). In the other 9 subjects, total peripheral resistance was well maintained even at presyncope (36%, group B). Cardiac output was smaller (3.26 ± 0.34 (SEM) vs. 5.02 ± 0.40 l min?1, P= 0.01), while total peripheral resistance was greater (1327 ± 117 vs. 903 ± 80 dyn s cm?5, P < 0.01) in group B than group A at presyncope. The steeper fall in cardiac output in group B was due to a drop in heart rate. MSNA decreased rapidly at presyncope after the onset of hypotension. Thus, a moderate fall in cardiac output with coincident vasodilatation or a marked fall in cardiac output with no changes in peripheral vascular resistance may contribute to (pre)syncope. However, an intrinsic impairment of vasomotor responsiveness and sympathetic baroreflex function is not the cause of neurally mediated (pre)syncope in this population.

Fu, Qi; Verheyden, Bart; Wieling, Wouter; Levine, Benjamin D

2012-01-01

60

Noninvasive cardiac output and blood pressure monitoring cannot replace an invasive monitoring system in critically ill patients  

PubMed Central

Background Monitoring of cardiac output and blood pressure are standard procedures in critical care medicine. Traditionally, invasive techniques like pulmonary artery catheter (PAC) and arterial catheters are widely used. Invasiveness bears many risks of deleterious complications. Therefore, a noninvasive reliable cardiac output (CO) and blood pressure monitoring system could improve the safety of cardiac monitoring. The aim of the present study was to compare a noninvasive versus a standard invasive cardiovascular monitoring system. Methods Nexfin HD is a continuous noninvasive blood pressure and cardiac output monitor system and is based on the development of the pulsatile unloading of the finger arterial walls using an inflatable finger cuff. During continuous BP measurement CO is calculated. We included 10 patients with standard invasive cardiac monitoring system (pulmonary artery catheter and arterial catheter) comparing invasively obtained data to the data collected noninvasively using the Nexfin HD. Results Correlation between mean arterial pressure measured with the standard arterial monitoring system and the Nexfin HD was r2 = 0.67 with a bias of -2 mmHg and two standard deviations of ± 16 mmHg. Correlation between CO derived from PAC and the Nexfin HD was r2 = 0.83 with a bias of 0.23 l/min and two standard deviations of ± 2.1 l/min; the percentage error was 29%. Conclusion Although the noninvasive CO measurement appears promising, the noninvasive blood pressure assessment is clearly less reliable than the invasively measured blood pressure. Therefore, according to the present data application of the Nexfin HD monitoring system in the ICU cannot be recommended generally. Whether such a tool might be reliable in certain critically ill patients remains to be determined.

Stover, John F; Stocker, Reto; Lenherr, Renato; Neff, Thomas A; Cottini, Silvia R; Zoller, Bernhard; Bechir, Markus

2009-01-01

61

Reproducibility of noninvasive cardiac output during arm exercise in spinal cord injury  

Microsoft Academic Search

The carbon dioxide (CO 2 ) rebreathing method is a noninvasive technique to estimate cardiac output during exer- cise, but few data are available on the validity and reliability of this measure in individuals with spinal cord injury (SCI). Six- teen male subjects with SCI (mean age 45 +\\/? 9, seven paraple- gic and nine tetraplegic) underwent three submaximal steady

Jonathan Myers; Heather Brown; Susan Smith; Inder Perkash; B. Jenny Kiratli

2007-01-01

62

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

63

Circulation Time in Man from Lung to Periphery as an Indirect Index of Cardiac Output  

Microsoft Academic Search

Circulation time (Ct) between lung and periphery may be a surrogate for cardiac output, estimated here, for the most part, as the time between taking a breath of nitrogen and peripheral detection of a desaturation pulse. Use of pulse oximetry involves an internal, instrument delay; however, using the ear, we found shortening with exercise (12.1 ± 0.37 sec, at rest;

Chris B. Wolff; Sophie K. Checkley; Georgina Bhageerutty; Himanshu Bhatt; Atholl Johnston; David Collier; Ilias Tachtsidis; N. Garvie; M. Rosenberg; Nigel Benjamin

64

Effect of Hemorrhage on Cardiac Output, PVP, Alodosterone and Diuresis during Immersion in Men  

NASA Technical Reports Server (NTRS)

The purpose of this study was to test the hypothesis that a reduction in blood volume would attenuate or eliminate immersion-induced increases in cardiac output (Q (sup dot) sub co)) and urine excretion, and to investigate accompanying vasoactive and fluid-electrolyte hormonal responses.

Simanonok, K.; Greenleaf, John E.; Bernauer, E. M.; Wade, C. E.; Keil, L. C.

1990-01-01

65

Exercise cardiac output following Skylab missions - The second manned Skylab mission  

NASA Technical Reports Server (NTRS)

Cardiac output was measured during preflight and postflight exercise-stress tests on the Skylab astronauts. In the postflight tests immediately following the 28-, 59-, and 84-d earth orbital missions, the astronauts exhibited an approximate 30% decrease in cardiac output coupled with an approximate 50% decrease in cardiac stroke volume during exercise. These changes were accompanied by elevated heart rates and significant increases in total systemic peripheral vascular resistance. Mean arterial pressure was unchanged. All parameters returned to normal preflight values within 30 d of the end of the orbital period. Duration of the zero-G exposure did not appear to influence either the magnitude of the hemodynamic changes or the time-course of their return to normal. These results are discussed in relation to other cardiovascular findings and possible mechanisms responsible for the observations are outlined.

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

1976-01-01

66

Assessing and improving teamwork in cardiac surgery  

Microsoft Academic Search

ObjectiveCardiac surgery (PCS) has a low error tolerance, is dependent upon sophisticated organisational structures and demands high levels of cognitive and technical performance. The aim of the study was to assess the role of intraoperative non-routine events (NREs) and team performance on paediatric cardiac surgery outcomes. The current paper focuses on improving methods for studying teamwork; a companion paper will

Jan Maarten Schraagen; Ton Schouten; Meike Smit; Felix Haas; Dolf van der Beek; Josine van de Ven; Paul Barach

2010-01-01

67

Investigations concerning the application of the cross-correlation method in cardiac output measurements  

PubMed Central

Background In spite of numerous non-invasive examinations the “gold clinical standard” of cardiac output measurements is the invasive pulmonary artery catheterization by means of the Swan-Ganz catheter and the application of the thermodilution method to estimate the blood flow. The results obtained by means of thermodilution are sensitive to many physical and biological disturbances. The unreliability of this method amounts to 20-45% and depends on the given variant of the method. Therefore some other method, more accurate and resistant to disturbances, was looked for. This paper presents a new approach to cardiac output measurements, based on cross-correlation signal analysis. The goal of investigations was to verify experimentally the application of the cross-correlation method of cardiac output measurements. Results In 99.2% of the examined cases the extreme of the cross-correlation function was easy to be estimated by numerical algorithms. In 0,8% of the remaining cases (with a plateau region adjacent to the maximum point) numerical detection of the extreme was inaccurate. The typical unreliability of the investigated method amounted o 5.1% (9.8% in the worst case). Investigations performed on a physical model revealed that the unreliability of cardiac output measurements by means of the cross-correlation method is 3–5 times better than in the case of thermodilution. Conclusions The performed investigations and theoretical analysis have shown, that the cross-correlation method may be applied in cardiac output measurements. This kind of measurements seems to be more accurate and disturbance-resistant than clinically applied thermodilution.

2012-01-01

68

Drug detection in breath: effects of pulmonary blood flow and cardiac output on propofol exhalation.  

PubMed

Breath analysis could offer a non-invasive means of intravenous drug monitoring if robust correlations between drug concentrations in breath and blood can be established. In this study, propofol blood and breath concentrations were determined in an animal model under varying physiological conditions. Propofol concentrations in breath were determined by means of two independently calibrated analytical methods: continuous, real-time proton transfer reaction mass spectrometry (PTR-MS) and discontinuous solid-phase micro-extraction coupled with gas chromatography mass spectrometry (SPME-GC-MS). Blood concentrations were determined by means of SPME-GC-MS. Effects of changes in pulmonary blood flow resulting in a decreased cardiac output (CO) and effects of dobutamine administration resulting in an increased CO on propofol breath concentrations and on the correlation between propofol blood and breath concentrations were investigated in seven acutely instrumented pigs. Discontinuous propofol determination in breath by means of alveolar sampling and SPME-GC-MS showed good agreement (R(2)=0.959) with continuous alveolar real-time measurement by means of PTR-MS. In all investigated animals, increasing cardiac output led to a deterioration of the relationship between breath and blood propofol concentrations (R(2)=0.783 for gas chromatography-mass spectrometry and R(2)=0.795 for PTR-MS). Decreasing pulmonary blood flow and cardiac output through banding of the pulmonary artery did not significantly affect the relationship between propofol breath and blood concentrations (R(2)>0.90). Estimation of propofol blood concentrations from exhaled alveolar concentrations seems possible by means of different analytical methods even when cardiac output is decreased. Increases in cardiac output preclude prediction of blood propofol concentration from exhaled concentrations. PMID:21643859

Kamysek, Svend; Fuchs, Patricia; Schwoebel, Henny; Roesner, Jan P; Kischkel, Sabine; Wolter, Kathi; Loeseken, Christian; Schubert, Jochen K; Miekisch, Wolfram

2011-10-01

69

Prediction of the Changes in Cardiac Output in Association with Preload Reduction Therapy in Patients with Hypertensive Heart Failure  

Microsoft Academic Search

In treating patients with acute hypertensive heart failure we often try preload-reduction therapy using diuretics or vasodilators, but this may frequently produce a considerable decrease in cardiac output, particularly in hypertensive patients with diastolic dysfunction. Therefore, it is important from the clinical standpoint to predict the change in cardiac output following preload-reduction therapy. The objective of this study was to

Reiko Nagano; Tohru Masuyama; Jung-Myung Lee; Kazuhiro Yamamoto; Johji Naito; Toshiaki Mano; Hiroya Kondo; Masatsugu Hori; Michitoshi Inoue; Takenobu Kamada

1997-01-01

70

Cardiac output, coronary blood flow, and blood gases during open-chest standard and compression-active-decompression cardiopulmonary resuscitation  

Microsoft Academic Search

Objective: To determine whether open-chest compression-active-decompression (CAD) could improve cardiac output, coronary blood flow, blood gases, and resuscitation compared to open-chest manual compression in a porcine model of cardiac arrest. Design: Prospective, randomized laboratory investigation for measurement of cardiac output, coronary blood flow, arterial and mixed venous blood gases and potassium levels, and return of spontaneous circulation. Subjects: Ten pigs

Milo Engoren; Fred Severyn; Nancy Fenn-Buderer; Michael DeFrank

2002-01-01

71

Comparison of dynamic measurements of pulse contour with pulsed heat continuous cardiac output in postoperative cardiac surgical patients.  

PubMed

Cardiac output (CO) can be measured using bolus thermodilution via a pulmonary artery catheter (PAC) and as continuous cardiac output (CCO), using pulsed heat thermoditution. Pulse contour cardiac output (PCCO) measures continuous CO by analysis of the arterial waveform after calibration with thermodilution CO. The Pulsion Medical Systems (PiCCO system) achieves this by transpulmonary aortic thermodilution (TDtpa). There is uncertainty regarding the agreement between TDtpa, CCO, and PCCO CO measurements in situations of rapid haemodynamic changes. We studied the agreement of the measures by comparing digital recordings of cardiac index (CI) determined by PCCO and CCO (PCCI and CCI, respectively) made during periods of haemodynamic instability. After ethics committee approval we studied four post-coronary artery bypass graft patients, in the immediate postoperative period. Each patient had a 7.5F CCO catheter (Edwards Lifesciences) and a 5F, 20cm PCCO femoral artery catheter. Digital recordings were obtained for the first 12-18 postoperative hours. Six epochs of instability were identified in the first two to three postoperative hours, and at the commencement of inotropic or vasoactive drugs. Notable features, despite frequent PCCO calibrations, were the marked difference of PCCI compared to CCI. In contradistinction, they tracked very closely during a period of stability. Limitations of both methods were noted. Whilst PCCO responded to rapid change, it developed significant error during haemodynmamic instability and requires frequent recalibration. CCO on the other hand has a considerable time lag in responding to changes in CO. The way a monitor measures CO must be taken into account when using the data in clinical management. PMID:17424793

Boyle, Martin; Lawrence, John; Belessis, Andrew; Murgo, Margherita; Shehabi, Yahya

2007-02-01

72

Estimation of cardiac output in patients with congestive heart failure by analysis of right ventricular pressure waveforms  

PubMed Central

Background Cardiac output (CO) is an important determinant of the hemodynamic state in patients with congestive heart failure (CHF). We tested the hypothesis that CO can be estimated from the right ventricular (RV) pressure waveform in CHF patients using a pulse contour cardiac output algorithm that considers constant but patient specific RV outflow tract characteristic impedance. Method In 12 patients with CHF, breath-by-breath Fick CO and RV pressure waveforms were recorded utilizing an implantable hemodynamic monitor during a bicycle exercise protocol. These data were analyzed retrospectively to assess changes in characteristic impedance of the RV outflow tract during exercise. Four patients that were implanted with an implantable cardiac defibrillator (ICD) implementing the algorithm were studied prospectively. During a two staged sub-maximal bicycle exercise test conducted at 4 and 16 weeks of implant, COs measured by direct Fick technique and estimated by the ICD were recorded and compared. Results At rest the total pulmonary arterial resistance and the characteristic impedance were 675 ± 345 and 48 ± 18 dyn.s.cm-5, respectively. During sub-maximal exercise, the total pulmonary arterial resistance decreased (? 91 ± 159 dyn.s.cm-5, p < 0.05) but the characteristic impedance was unaffected (? 3 ± 9 dyn.s.cm-5, NS). The algorithm derived cardiac output estimates correlated with Fick CO (7.6 ± 2.5 L/min, R2 = 0.92) with a limit of agreement of 1.7 L/min and tracked changes in Fick CO (R2 = 0.73). Conclusions The analysis of right ventricular pressure waveforms continuously recorded by an implantable hemodynamic monitor provides an estimate of CO and may prove useful in guiding treatment in patients with CHF.

2011-01-01

73

Quantification of mitral regurgitation by automated cardiac output measurement: experimental and clinical validation  

NASA Technical Reports Server (NTRS)

OBJECTIVES: To develop and validate an automated noninvasive method to quantify mitral regurgitation. BACKGROUND: Automated cardiac output measurement (ACM), which integrates digital color Doppler velocities in space and in time, has been validated for the left ventricular (LV) outflow tract but has not been tested for the LV inflow tract or to assess mitral regurgitation (MR). METHODS: First, to validate ACM against a gold standard (ultrasonic flow meter), 8 dogs were studied at 40 different stages of cardiac output (CO). Second, to compare ACM to the LV outflow (ACMa) and inflow (ACMm) tracts, 50 normal volunteers without MR or aortic regurgitation (44+/-5 years, 31 male) were studied. Third, to compare ACM with the standard pulsed Doppler-two-dimensional echocardiographic (PD-2D) method for quantification of MR, 51 patients (61+/-14 years, 30 male) with MR were studied. RESULTS: In the canine studies, CO by ACM (1.32+/-0.3 liter/min, y) and flow meter (1.35+/-0.3 liter/min, x) showed good correlation (r=0.95, y=0.89x+0.11) and agreement (deltaCO(y-x)=0.03+/-0.08 [mean+/-SD] liter/min). In the normal subjects, CO measured by ACMm agreed with CO by ACMa (r=0.90, p < 0.0001, deltaCO=-0.09+/-0.42 liter/min), PD (r=0.87, p < 0.0001, deltaCO=0.12+/-0.49 liter/min) and 2D (r=0.84, p < 0.0001, deltaCO=-0.16+/-0.48 liter/min). In the patients, mitral regurgitant volume (MRV) by ACMm-ACMa agreed with PD-2D (r= 0.88, y=0.88x+6.6, p < 0.0001, deltaMRV=2.68+/-9.7 ml). CONCLUSIONS: We determined that ACM is a feasible new method for quantifying LV outflow and inflow volume to measure MRV and that ACM automatically performs calculations that are equivalent to more time-consuming Doppler and 2D measurements. Additionally, ACM should improve MR quantification in routine clinical practice.

Sun, J. P.; Yang, X. S.; Qin, J. X.; Greenberg, N. L.; Zhou, J.; Vazquez, C. J.; Griffin, B. P.; Stewart, W. J.; Thomas, J. D.

1998-01-01

74

Extracorporeal life support with an integrated left ventricular vent in children with a low cardiac output.  

PubMed

Background: The aim of this study was to evaluate our experience in central extracorporeal life support with an integrated left ventricular vent in children with cardiac failure. Methods: Eight children acquired extracorporeal life support with a left ventricular vent, either after cardiac surgery (n = 4) or during an acute cardiac illness (n = 4). The ascending aorta and right atrium were cannulated. The left ventricular vent was inserted through the right superior pulmonary vein and connected to the venous line on the extracorporeal life support such that active left heart decompression was achieved. Results: No patient died while on support, seven patients were successfully weaned from it and one patient was transitioned to a biventricular assist device. The median length of support was 6 days (range 5-10 days). One patient died while in the hospital, despite successful weaning from extracorporeal life support. No intra-cardiac thrombus or embolic stroke was observed. No patient developed relevant intracranial bleeding resulting in neurological dysfunction during and after extracorporeal life support. Conclusions: In case of a low cardiac output and an insufficient inter-atrial shunt, additional left ventricular decompression via a vent could help avoid left heart distension and might promote myocardial recovery. In pulmonary dysfunction, separate blood gas analyses from the venous cannula and the left ventricular vent help detect possible coronary hypoxia when the left ventricle begins to recover. We recommend the use of central extracorporeal life support with an integrated left ventricular vent in children with intractable cardiac failure. PMID:23919969

Sandrio, Stany; Springer, Wolfgang; Karck, Matthias; Gorenflo, Matthias; Weymann, Alexander; Ruhparwar, Arjang; Loukanov, Tsvetomir

2014-08-01

75

Automated non-invasive measurement of cardiac output by the carbon dioxide rebreathing method: comparisons with dye dilution and thermodilution.  

PubMed Central

The accuracy and reproducibility of indirect measurement of cardiac output at rest by the carbon dioxide rebreathing (indirect Fick) method with an automated respiratory analysis system (Gould 9000IV) were compared with simultaneous measurements made in duplicate by dye dilution and thermodilution in 25 patients having cardiac catheterisation studies. Measurements of cardiac output by the carbon dioxide rebreathing method were not significantly different from those obtained with dye dilution (mean difference -0.3 l/min, SD 0.76, 95% confidence interval -0.7 to 0.1). Thermodilution significantly over-estimated cardiac output by a mean of 2.2 l/min or 39% (SD 1.5, 95% confidence interval 1.6 to 2.8) compared with the carbon dioxide rebreathing method and significantly overestimated cardiac output by 1.9 l/min or 31% (SD 1.2, 95% confidence interval 1.2 to 2.5) compared with dye dilution. The reproducibility of measurements of cardiac output in individual patients was satisfactory with the dye dilution method but was poor with carbon dioxide rebreathing and thermodilution. Indirect measurement of resting cardiac output by the Gould 9000IV automated carbon dioxide rebreathing method is more accurate but the variability inherent with this method requires that multiple measurements be taken for each determination. Measurement of cardiac output by the thermodilution method by a commercially available cardiac output computer was not satisfactory because not only was there considerable variability between repeat measurements but the method also consistently overestimated cardiac output compared with the dye dilution method.

Russell, A E; Smith, S A; West, M J; Aylward, P E; McRitchie, R J; Hassam, R M; Minson, R B; Wing, L M; Chalmers, J P

1990-01-01

76

A comparison of pulse contour wave analysis and ultrasonic cardiac output monitoring in the critically ill.  

PubMed

Cardiac output (CO) is a key determinant of major organ blood flow and solute delivery to drug eliminating organs. As such, CO assessment is a key covariate in understanding altered drug handling in the critically ill. Newer minimally-invasive devices are providing unique platforms for such an application, although comparison data are currently lacking. In this study we evaluated the Vigileo (Edwards Lifesciences, Irvine, CA, USA) and USCOM (USCOM Ltd, Sydney, NSW) devices in 62 critically ill patients requiring antibacterial therapy. The mean COVigileo and COUSCOM for the first paired measurements were 8.20±2.65 l/minute and 6.84±2.57 l/minute respectively (P <0.001). A significant correlation was evident in all patients (r=0.537, P <0.001) although the recorded bias was large (1.36±2.51 l/minute, limits of agreement -3.6 to±6.3 l/minute). The overall percentage error was 65%. There was an improved correlation in those admitted with sepsis (r=0.639, P <0.001), compared to trauma (r=0.373, P=0.066), although bias, precision and percentage error were similar in both subgroups. In 54 patients a second paired assessment was obtained at three hours. A weak, although significant correlation (r=0.377, P=0.005) was observed suggesting that gross trends over time were similar. In conclusion, our findings demonstrate poor agreement between these techniques suggesting that these devices are not simply interchangeable when assessing CO in a research or clinical setting. PMID:22813490

Udy, A A; Altukroni, M; Jarrett, P; Roberts, J A; Lipman, J

2012-07-01

77

[Non-invasive cardiac output measurement with USCOM in air rescue operation].  

PubMed

In cardiac emergency events (NACA score = 3.4), a non-invasive cardiac output test involving transaortalic blood flow velocity measurement was used in the air rescue of 30 patients. An average velocity integral (Vti) of 21.9 +/- 9.9 cm was determined in the short examination time (t = 120 +/- 30 sec). Related to the middle body surface (BSA = 2.0 +/- 0.3 m (2)), the calculated cardiac index (CI) was 2.6 +/- 1.1 l/min/m (2). The CI was under 2.2 l/min/m (2) in 12 examinations (40 %). 5 patients in this group subsequently received catecholamine therapy. Thrombolysis therapy increased by 17 % in the myocardial infarction group with CI

Schedler, O; Handschak, H; Hensel, M

2008-12-01

78

Cardiac output in single-lead VDD pacing versus rate-matched VVIR pacing.  

PubMed

The importance of atrioventricular synchronous pacing compared with single-chamber rate-responsive pacing is still under discussion, especially for low-intensity workload representing daily life activities. We evaluated hemodynamics in single-lead VDD pacing versus VVIR pacing in 11 patients (8 men and 3 women, aged 58.6 +/- 13.8 years) with normal left ventricular function and a previously implanted single-lead VDDR pacemaker. A low-intensity steady-state treadmill test at 1 to 2.5 mph with a gradient of 2% to 4% was performed. Cardiac output was determined using a standard carbon dioxide rebreathing technique. Initially, the VDD mode was programmed, and after 5 minutes of exercise, cardiac output was measured in steady-state conditions. The pacemaker was then reprogrammed to the VVI mode at a rate 5 to 10 beats above the maximal atrial tracking rate to simulate rate-matched VVIR pacing (VVIRm). After 5 additional minutes of steady-state exercise, cardiac output was measured again. The maximal atrial rate in the VDD mode was 119 +/- 19 beats/min versus a programmed rate of 129 +/- 18 beats/min in the VVIRm mode. VDD pacing resulted in a significantly higher cardiac output than VVIRm pacing (10.6 +/- 1.9 vs 9.2 +/- 1.4 L/min; p < 0.002), with a mean difference of 1.6 +/- 1.2 L/min between the 2 modes. In the VDD mode, stroke volume (90.7 +/- 20.1 vs 71.6 +/- 13.0 ml; p < 0.001) and maximal oxygen uptake (1,183 +/- 264 vs 1,076 +/- 289 ml/min, p < 0.01) were also higher than in VVIRm.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7732998

Nowak, B; Voigtländer, T; Himmrich, E; Liebrich, A; Poschmann, G; Epperlein, S; Treese, N; Meyer, J

1995-05-01

79

Noninvasive Cardiac Output Determination for Children by the Inert Gas-Rebreathing Method  

Microsoft Academic Search

Standard methods for determination of cardiac output (CO) are either invasive or technically demanding. Measurement of CO\\u000a by the inert gas–rebreathing (IGR) method, applied successfully in adults, uses a low-concentration mixture of an inert and\\u000a a blood-soluble gas, respectively. This study tested the feasibility of this method for determining CO during exercise for\\u000a pediatric patients with complete congenital atrioventricular block

Gesa Wiegand; Gunter Kerst; Winfried Baden; Michael Hofbeck

2010-01-01

80

Dynamic vs. fixed bag filling: Impact on cardiac output rebreathing protocol  

Microsoft Academic Search

A main purpose of this study was to compare the repeatability (2.77 multiplied by the within-subject SD) between two different rebreathing protocols on cardiac output (Q?), pulmonary diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO), and pulmonary capillary blood volume (Vc). This study compared two bag volume conditions [Fixed Bag Volume (FBV)=BV fixed at 60% of forced vital

Gerald S. Zavorsky; Kenneth C. Beck; Lauren M. Cass; Raul Artal; Peter D. Wagner

2010-01-01

81

A comparison of the Nexfin® and transcardiopulmonary thermodilution to estimate cardiac output during coronary artery surgery.  

PubMed

The newly introduced Nexfin(®) device allows analysis of the blood pressure trace produced by a non-invasive finger cuff. We compared the cardiac output derived from the Nexfin and PiCCO, using transcardiopulmonary thermodilution, during cardiac surgery. Forty patients with preserved left ventricular function undergoing elective coronary artery bypass graft surgery were studied after induction of general anaesthesia and until discharge to the intensive care unit. There was a significant correlation between Nexfin and PiCCO before (r(2) = 0.81, p < 0.001) and after (r(2) = 0.56, p < 0.001) cardiopulmonary bypass. Bland-Altman analysis demonstrated the mean bias of Nexfin to be -0.1 (95% limits of agreement -0.6 to +0.5, percentage error 23%) and -0.1 (-0.8 to +0.6, 26%) l.min(-1).m(-2), before and after cardiopulmonary bypass, respectively. After a passive leg-raise was performed, there was also good correlation between the two methods, both before (r(2) = 0.72, p < 0.001) and after (r(2) = 0.76, p < 0.001) cardiopulmonary bypass. We conclude that the Nexfin is a reliable method of measuring cardiac output during and after cardiac surgery. PMID:22324797

Broch, O; Renner, J; Gruenewald, M; Meybohm, P; Schöttler, J; Caliebe, A; Steinfath, M; Malbrain, M; Bein, B

2012-04-01

82

Validation and application of single breath cardiac output determinations in man  

NASA Technical Reports Server (NTRS)

The results of a procedure for estimating cardiac output by a single-breath technique (Qsb), obtained in healthy males during supine rest and during exercise on a bicycle ergometer, were compared with the results on cardiac output obtained by the direct Fick method (QF). The single breath maneuver consisted of a slow exhalation to near residual volume following an inspiration somewhat deeper than normal. The Qsb calculations incorporated an equation of the CO2 dissociation curve and a 'moving spline' sequential curve-fitting technique to calculate the instantaneous R from points on the original expirogram. The resulting linear regression equation indicated a 24-percent underestimation of QF by the Qsb technique. After applying a correction, the Qsb-QF relationship was improved. A subsequent study during upright rest and exercise to 80 percent of VO2(max) in 6 subjects indicated a close linear relationship between Qsb and VO2 for all 95 values obtained, with slope and intercept close to those in published studies in which invasive cardiac output measurements were used.

Loeppky, J. A.; Fletcher, E. R.; Myhre, L. G.; Luft, U. C.

1986-01-01

83

Monitoring cardiac output trends with end-tidal carbon dioxide pressures in off-pump coronary bypass.  

PubMed

The optimum method of intraoperative monitoring in patients undergoing off-pump coronary bypass remains debatable. Using capnography and end-tidal carbon dioxide pressure may be a helpful method of monitoring cardiac output trends, especially when grafting posterior and lateral vessels. After repositioning the heart, End-tidal carbon dioxide pressures that continue to trend down usually indicate decreased cardiac output and precede hemodynamic and electrical instability. The advantages of this method include simplicity, universal availability, and a short response time to changes in cardiac output. PMID:21524440

Saleh, Hesham Z; Pullan, D Mark

2011-05-01

84

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.

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

2012-01-01

85

Recurrent gastrointestinal bleeding and high output cardiac failure caused by hereditary hemorrhagic telangiectasia.  

PubMed

Hereditary hemorrhagic telangiectasia, commonly known as Osler-Weber-Rendu disease, is a systemic autosomal dominant inherited disorder, that occurs in Caucasian populations. We report the case of a 56-year-old housewife who was admitted to the gastrointestinal and cardiovascular ward because she had suffered from recurrent gastrointestinal bleeding and heart failure from 1994 to 1997. Panendoscopy showed vascular ectasia scattered over the tongue, larynx, esophagus, and posterior wall of the gastric body. Colonoscopy showed clusters of telangiectasia over the cecum and ascending colon. Arteriovenous malformations (AVMs) were found in the liver and lungs on computerized tomography. Recurrent gastrointestinal bleeding was controlled by estrogen treatment during the follow-up period. In July 1997, the patient was readmitted to our cardiovascular section due to aggravated dyspnea, orthopnea and bilateral lower leg edema. Cardiac catheterization showed a large fistula from the left pulmonary artery to the left atrium and left ventricle, pulmonary arterial pressure of 37/13 mmHg and cardiac output of 9.61/minute. Other studies excluded the possibility of sepsis, and high-output cardiac failure was suspected. The patient was discharged in a stable condition and scheduled for AVM embolization management. Unfortunately, she died of a suspected heart attack at home two weeks following discharge. PMID:10820915

Lin, C P; Cheng, J S; Lai, K H; Lo, G H; Pan, H B

2000-04-01

86

Cardiac output measurement in critically ill patients: comparison of continuous and conventional thermodilution techniques.  

PubMed

The purpose of the study was to compare cardiac output (CO) measurement by continuous (CTD) with that by conventional thermodilution (TD) in critically ill patients. In 19 of 20 critically ill patients requiring a pulmonary artery catheterism, 105 paired CO measurements were performed by both CTD and TD. Regression analysis showed that: CTD CO = 1.18 TD CO - 0.47. Correlation coefficient was 0.96. Bias and limit of agreement were -0.8 and 2.4 L.min-1, respectively. When a Bland and Altman diagram was constructed according to cardiac index ranges, biases were -0.2 and -0.3 and -0.8 L.min-1.m-2 and limits of agreement were 0.3, 0.7 and 1.6 L.min-1.m-2 for low (< 2.5 L.min-1.m-2), normal (between 2.5 and 4.5 L.min-1.m-2) and high (> 4.5 L.min-1.m-2) cardiac indexes, respectively. It is concluded that CTD, compared with TD, is a reliable method of measuring CO, especially when cardiac index is < or = 4.5 L.min-1.m-2. PMID:8590506

Lefrant, J Y; Bruelle, P; Ripart, J; Ibanez, F; Aya, G; Peray, P; Saïssi, G; de La Coussaye, J E; Eledjam, J J

1995-11-01

87

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

88

The clinical application of pulse contour cardiac output and intrathoracic volume measurements in critically ill patients.  

PubMed

Cardiac output (CO) determination by pulmonary artery (PA) catheter has increasingly been criticised within the literature due to its invasive nature and poor correlation between the pressure measurements and intravascular volume status in mechanically ventilated patients. Consequently, alternative less invasive technologies to PA catheterisation are emerging within intensive care. One such novel technology are pulse contour CO (PCCO) systems. They establish comprehensive and continuous haemodynamic monitoring utilising a central venous catheter (CVC) and an arterial line. Furthermore, a key feature of this technology is its ability to produce intrathoracic volume measurements which may provide a better estimation of cardiac preload as well as indicate the presence and severity of pulmonary oedema. This article aims to discuss the theoretical basis and clinical application of PCCO systems, how PCCO systems differ from PA catheters and how the intrathoracic volume measurements are derived. Understanding these advanced concepts will ensure that clinicians are able to employ this innovative monitoring technology more effectively. PMID:16933635

Hewitt, Nicky A; Braaf, Sandra C

2006-08-01

89

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

90

Sensitivity of Outcome Assessment in Cardiac Rehabilitation.  

ERIC Educational Resources Information Center

Differential sensitivity to change of three measures of men who participated in cardiac rehabilitation was measured to evaluate the hypothesis that measures that enhance subjective health and well-being are more appropriate to assess change than are measures of psychopathology. Rehabilitation subjects, but not control subjects, reported a decrease…

Denollet, Johan

1993-01-01

91

The consistency of cardiac output measurement (CO 2 rebreathe) in children during exercise  

Microsoft Academic Search

Summary  Exercise cardiac output (\\u000a$$\\\\dot Q$$\\u000a) was determined using the CO2 rebreathing equilibrium method. Five repeat tests in 12 boys and two tests over a 4 month interval in 47 boys were performed. Regression equations to predict \\u000a$$\\\\dot Q$$\\u000a from \\u000a$$\\\\dot V$$\\u000aO2 were in close agreement with dye dilution studies in boys (Eriksson and Koch 1973). Group mean

D. H. Paterson; D. A. Cunningham; M. J. Plyley; C. J. R. Blimkie; A. P. Donner

1982-01-01

92

Improved Accuracy Of Cardiac Output Estimation By The Partial CO 2 Rebreathing Method  

Microsoft Academic Search

Objective  This study investigated the accuracy of the NICO monitor equipped with the newer software. Additionally, the effects of the\\u000a increased dead space produced by the NICO monitor on ventilatory settings were investi-\\u0009gated.\\u000a \\u000a \\u000a \\u000a Methods  Forty-two patients undergoing elective aortic reconstruction participated in this prospective, obser-\\u0009vational study at a\\u000a university hospital. Cardiac output was continuously monitored using both the NICO monitor

Yoshifumi Kotake; Takashige Yamada; Hiromasa Nagata; Takeshi Suzuki; Ryohei Serita; Nobuyuki Katori; Junzo Takeda; Hideyuki Shimizu

2009-01-01

93

Cardiac Output Derived From Left Ventricular Pressure During Conductance Catheter Evaluations: An Extended Modelflow Method  

Microsoft Academic Search

Objective  The Modelflow method computes cardiac output (CO) from arterial pressure (CO-MFao) by simulating a non-linear three-element\\u000a Windkessel model of aortic input impedance. We present a novel technique to apply the Modelflow method to the left ventricular\\u000a pressure (Plv) signal, to obtain an estimation of CO (CO-MFlv).\\u000a \\u000a \\u000a \\u000a Methods  We extended the model by simulating the aortic valve as a resistance placed in

Sergio Valsecchi; Giovanni B. Perego; Jan J. Schreuder; Federica Censi; Jos R. C. Jansen

2007-01-01

94

Effect of aging on power output properties in rat skinned cardiac myocytes.  

PubMed

Aging is generally associated with a decline in several indices of cardiac function. The cellular mechanisms for this decline are not completely understood. The ability of the myocardium to perform external work (power output) is a critical aspect of ventricular function. The purpose of this study was to determine the effect of aging on loaded shortening and power output properties. We measured force-velocity properties in permeabilized (skinned) myocytes from the hearts of 9-, 24-, and 33-month-old male Fisher 344 × Brown Norway F1 hybrid rats (F344BN) during loaded contractions using a force-clamp technique. Power output was calculated by multiplying force and shortening velocity values. We found that peak power output normalized to maximal force was significantly decreased by 18% and 31% in myocytes from 24- and 33-month-old group, respectively, compared with 9-month group (p < .05). These results suggest that aging is associated with a significant decrease in the ability of the myocardium to do work. PMID:21896503

Chung, Eunhee; Diffee, Gary M

2011-12-01

95

Measurement of cardiac output by the thermodilution method in rats. II. Simultaneous measurement of cardiac output and blood pressure in conscious rats.  

PubMed

A method is described for the simultaneous measurement of cardiac output (CO), using the thermodilution method, and arterial blood pressure in conscious unrestrained rats. For the injection of the indicator solution (ice-cold, 0.9% saline) and for the measurement of systolic and diastolic blood pressure, chronically-implanted polyethylene cathethers were used, while CO was measured transpulmonarily with a commercially available CO computer and an acutely-implanted (via caudal artery) arterial thermistor catheter. The following were observed in 10 rats at rest: a CO of 40.2 +/- 1.9 ml/min/100 g, a mean arterial blood pressure of 106 +/- 5 mmHg, a heart rate of 417 +/- 20 beats/min and a peripheral vascular resistance of 2.68 +/- 0.13 mmHG/(ml/min/100 g). After injection of the beta-adrenergic agonist isoprenaline, there was a rise in CO and heart rate, while peripheral resistance and blood pressure were lowered. Injection of the beta-receptor-blocked propranolol caused decreases in CO and heart rate, while peripheral resistance and blood pressure rose. It is concluded, that the method described here for the simultaneous measurement of CO and arterial blood pressure is suitable for the investigation of drug-induced cardiovascular effects in conscious rats. PMID:7265984

Müller, B; Mannesmann, G

1981-01-01

96

Comparison of cardiac output measurements in critically ill patients: FloTrac/Vigileo vs transthoracic Doppler echocardiography.  

PubMed

Measurement of cardiac output is an integral part of patient management in the intensive care unit. FloTrac/Vigileo is a continuous cardiac output monitoring device that does not need re-calibration. However its reliability has been questioned in some studies, especially involving surgical patients. In this study, we evaluated the comparability of FloTrac/Vigileo and transthoracic Doppler echocardiography in 53 critically ill patients requiring continuous cardiac output monitoring. Most of these patients had septic or cardiogenic shock. Cardiac output was measured by both FloTrac/Vigileo and transthoracic Doppler echocardiography. The bias and precision (mean and SD) between the two devices was 0.35 +/- 1.35 l/minute. The limits of agreement were -2.3 to 3.0 l/minute (%error = 49.3%). When patients with irregular heart rhythms and aortic stenosis were excluded, the bias and precision was 0.02 +/- 0.80 l/minute (n = 42). The limits of agreement were -1.55 to 1.59 l/minute (%error = 29.5%). Patient demographics (body surface area, gender and age) did not affect the bias, but there was a mild tendency for FloTrac/ Vigileo to register a higher cardiac output at high heart rates. Changes in cardiac output for two consecutive days correlated well between the two methods (r = 0.86; P < 0.001). In summary, with the exceptions of patients with irregular heart rhythms and significant aortic stenosis, FloTrac/Vigileo is clinically comparable to transthoracic Doppler echocardiography in cardiac output measurements in critically ill patients. PMID:21823375

McLean, A S; Huang, S J; Kot, M; Rajamani, A; Hoyling, L

2011-07-01

97

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

98

Effect of norepinephrine dosage and calibration frequency on accuracy of pulse contour-derived cardiac output  

PubMed Central

Introduction Continuous cardiac output monitoring is used for early detection of hemodynamic instability and guidance of therapy in critically ill patients. Recently, the accuracy of pulse contour-derived cardiac output (PCCO) has been questioned in different clinical situations. In this study, we examined agreement between PCCO and transcardiopulmonary thermodilution cardiac output (COTCP) in critically ill patients, with special emphasis on norepinephrine (NE) administration and the time interval between calibrations. Methods This prospective, observational study was performed with a sample of 73 patients (mean age, 63 ± 13 years) requiring invasive hemodynamic monitoring on a non-cardiac surgery intensive care unit. PCCO was recorded immediately before calibration by COTCP. Bland-Altman analysis was performed on data subsets comparing agreement between PCCO and COTCP according to NE dosage and the time interval between calibrations up to 24 hours. Further, central artery stiffness was calculated on the basis of the pulse pressure to stroke volume relationship. Results A total of 330 data pairs were analyzed. For all data pairs, the mean COTCP (±SD) was 8.2 ± 2.0 L/min. PCCO had a mean bias of 0.16 L/min with limits of agreement of -2.81 to 3.15 L/min (percentage error, 38%) when compared to COTCP. Whereas the bias between PCCO and COTCP was not significantly different between NE dosage categories or categories of time elapsed between calibrations, interchangeability (percentage error <30%) between methods was present only in the high NE dosage subgroup (?0.1 ?g/kg/min), as the percentage errors were 40%, 47% and 28% in the no NE, NE < 0.1 and NE ? 0.1 ?g/kg/min subgroups, respectively. PCCO was not interchangeable with COTCP in subgroups of different calibration intervals. The high NE dosage group showed significantly increased central artery stiffness. Conclusions This study shows that NE dosage, but not the time interval between calibrations, has an impact on the agreement between PCCO and COTCP. Only in the measurements with high NE dosage (representing the minority of measurements) was PCCO interchangeable with COTCP.

2011-01-01

99

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

PubMed Central

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 subjects. Cardiac output values obtained with impedance cardiography were significantly correlated with those measured by the indirect Fick method, although there was a wide scatter with over 73% of the readings lying outside the limits defined by the line of identity +/- 20%. This correlation was greatly reduced when stroke volume index was used instead of cardiac output. Indirect Fick results were linearly related to oxygen uptake both at rest and on exercise, while impedance cardiography results did not correlate with oxygen uptake. Impedance cardiography gave consistently lower results for cardiac output than indirect Fick at all levels of exercise. Both machines were easy to use and produced acceptable mean (SE) coefficients of variation (BoMed NCCOM3 7.7 (1.0)%, Gould 9000 IV 10.6 (1.4)%). Further validation is required before either of these machines can be recommended as an alternative to invasive monitoring in clinical practice.

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

1988-01-01

100

The Neuromuscular Transform of the Lobster Cardiac System Explains the Opposing Effects of a Neuromodulator on Muscle Output  

PubMed Central

Motor neuron activity is transformed into muscle movement through a cascade of complex molecular and biomechanical events. This nonlinear mapping of neural inputs to motor behaviors is called the neuromuscular transform (NMT). We examined the NMT in the cardiac system of the lobster Homarus americanus by stimulating a cardiac motor nerve with rhythmic bursts of action potentials and measuring muscle movements in response to different stimulation patterns. The NMT was similar across preparations, which suggested that it could be used to predict muscle movement from spontaneous neural activity in the intact heart. We assessed this possibility across semi-intact heart preparations in two separate analyses. First, we performed a linear regression analysis across 122 preparations in physiological saline to predict muscle movements from neural activity. Under these conditions, the NMT was predictive of contraction duty cycle but was unable to predict contraction amplitude, likely as a result of uncontrolled interanimal variability. Second, we assessed the ability of the NMT to predict changes in motor output induced by the neuropeptide C-type allatostatin. Wiwatpanit et al. (2012) showed that bath application of C-type allatostatin produced either increases or decreases in the amplitude of the lobster heart contractions. We show that an important component of these preparation-dependent effects can arise from quantifiable differences in the basal state of each preparation and the nonlinear form of the NMT. These results illustrate how properly characterizing the relationships between neural activity and measurable physiological outputs can provide insight into seemingly idiosyncratic effects of neuromodulators across individuals.

Williams, Alex H.; Calkins, Andrew; O'Leary, Timothy; Symonds, Renee; Marder, Eve

2013-01-01

101

Simulation evaluation of quantitative myocardial perfusion assessment from cardiac CT  

NASA Astrophysics Data System (ADS)

Contrast enhancement on cardiac CT provides valuable information about myocardial perfusion and methods have been proposed to assess perfusion with static and dynamic acquisitions. There is a lack of knowledge and consensus on the appropriate approach to ensure 1) sufficient diagnostic accuracy for clinical decisions and 2) low radiation doses for patient safety. This work developed a thorough dynamic CT simulation and several accepted blood flow estimation techniques to evaluate the performance of perfusion assessment across a range of acquisition and estimation scenarios. Cardiac CT acquisitions were simulated for a range of flow states (Flow = 0.5, 1, 2, 3 ml/g/min, cardiac output = 3,5,8 L/min). CT acquisitions were simulated with a validated CT simulator incorporating polyenergetic data acquisition and realistic x-ray flux levels for dynamic acquisitions with a range of scenarios including 1, 2, 3 sec sampling for 30 sec with 25, 70, 140 mAs. Images were generated using conventional image reconstruction with additional image-based beam hardening correction to account for iodine content. Time attenuation curves were extracted for multiple regions around the myocardium and used to estimate flow. In total, 2,700 independent realizations of dynamic sequences were generated and multiple MBF estimation methods were applied to each of these. Evaluation of quantitative kinetic modeling yielded blood flow estimates with an root mean square error (RMSE) of ~0.6 ml/g/min averaged across multiple scenarios. Semi-quantitative modeling and qualitative static imaging resulted in significantly more error (RMSE = ~1.2 and ~1.2 ml/min/g respectively). For quantitative methods, dose reduction through reduced temporal sampling or reduced tube current had comparable impact on the MBF estimate fidelity. On average, half dose acquisitions increased the RMSE of estimates by only 18% suggesting that substantial dose reductions can be employed in the context of quantitative myocardial blood flow estimation. In conclusion, quantitative model-based dynamic cardiac CT perfusion assessment is capable of accurately estimating MBF across a range of cardiac outputs and tissue perfusion states, outperforms comparable static perfusion estimates, and is relatively robust to noise and temporal subsampling.

Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

2014-03-01

102

Validation of the use of foreign gas rebreathing method for non-invasive determination of cardiac output in heart disease patients  

Microsoft Academic Search

Objective: To compare a new device (Innocor) for non-invasive measurement of cardiac output (CO) by foreign gas rebreathing\\u000a method with conventional techniques used in the measurements of cardiac function. Methods: Cardiac outputs measured by Innocor\\u000a (CORB) were compared with CO obtained by echocardiography (COEC), Swan-Ganz thermodilution (COTD), and left ventricle radiography (COLVR) in 34 patients subjected to cardiac catheterization. Values

Liang Dong; Jian-an Wang; Chen-yang Jiang

2005-01-01

103

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

104

Reference values for total blood volume and cardiac output in humans  

SciTech Connect

Much research has been devoted to measurement of total blood volume (TBV) and cardiac output (CO) in humans but not enough effort has been devoted to collection and reduction of results for the purpose of deriving typical or {open_quotes}reference{close_quotes} values. Identification of normal values for TBV and CO is needed not only for clinical evaluations but also for the development of biokinetic models for ultra-short-lived radionuclides used in nuclear medicine (Leggett and Williams 1989). The purpose of this report is to offer reference values for TBV and CO, along with estimates of the associated uncertainties that arise from intra- and inter-subject variation, errors in measurement techniques, and other sources. Reference values are derived for basal supine CO and TBV in reference adult humans, and differences associated with age, sex, body size, body position, exercise, and other circumstances are discussed.

Williams, L.R. [Indiana Univ., South Bend, IN (United States). Division of Liberal Arts and Sciences] [Indiana Univ., South Bend, IN (United States). Division of Liberal Arts and Sciences

1994-09-01

105

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.

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

2014-01-01

106

Cardiac output distribution in response to hypoxia in the chick embryo in the second half of the incubation time.  

PubMed

1. The fetus develops cardiovascular adaptations to protect vital organs in situations such as hypoxia and asphyxia. These include bradycardia, increased systemic blood pressure and redistribution of the cardiac output. The extent to which they involve maternal or placenta influences is not known. The objective of the present work was to study the cardiac output distribution in response to hypoxia in the chick embryo, which is independent of the mother. 2. Fertilized eggs were studied at three incubation times (10-13 days, 14-16 days and 17-19 days of a normal incubation time of 21 days). Eggs were placed in a Plexiglass box in which the oxygen concentration could be changed. Eggs were opened at the air cell and a chorioallantoic vein was catheterized. Cardiac output distribution was measured with 15 micron fluorescent microspheres injected during normoxia, during the last minute of a 5 min period of hypoxia and after 5 min of subsequent reoxygenation. 3. Hypoxia caused a redistribution of the cardiac output in favour of heart (+17 to +160 % of baseline) and brain (+21 to +57 % of baseline) at the expense of liver (-3 to -65 % of baseline), yolk-sac (-46 to -77 % of baseline) and carcass (-6 to -33 % of baseline). 4. The magnitude of the changes in cardiac output distribution to the heart, brain, liver and carcass in response to hypoxia increased with advancing incubation time. 5. The data demonstrate the development of a protective redistribution of the cardiac output in response to hypoxia in the chick embryo from day 10 of incubation. PMID:9490852

Mulder, A L; van Golde, J C; Prinzen, F W; Blanco, C E

1998-04-01

107

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

108

Pulse contour cardiac output system use in pediatric orthotopic liver transplantation: preliminary report of nine patients.  

PubMed

Anesthetic management of orthotopic liver transplantation (OLT) in pediatric patients is challenging in terms of intraoperative bleeding, fluid management, and hemodynamic monitoring. The pulse contour cardiac output (PiCCO) system, a relatively new device based on the single-indicator transaortic thermodilution technique, may be useful for intraoperative hemodynamic monitoring in pediatric patients. This is a preliminary report of PiCCO use in nine children (aged 9.8 +/- 4.7 years) undergoing OLT. Hemodynamic volumetric parameters monitored by the PiCCO system were mean arterial pressure (MAP), cardiac index (CI), intrathoracic blood volume index (ITBVI), extravascular lung water index (EVLWI), systemic vascular resistance index (SVRI), and stroke volume variability (SVV). All parameters were recorded at anesthesia induction (T0), at the end of the anhepatic phase (Tanhepatic), and at the end of operation (Tend). The PiCCO system revealed similar MAP, CI, EVLWI, SVV, and SVRI values at all measurement intervals. Despite similar central venous pressure measurements, ITBVI values indicated significantly lower values at Tanhepatic than at T0 (627 +/- 160 mL/m2 and 751 +/- 151 mL/m2, respectively, P = .013). There were no PiCCO catheter-related complications in any patient. These findings demonstrate that the PiCCO system is a safe, continuous, multiparameter invasive monitoring device for use in pediatric patients undergoing OLT. This system may provide valuable data during pediatric OLT and appears to be a promising monitoring tool in these patients. PMID:16213339

Torgay, A; Pirat, A; Akpek, E; Zeyneloglu, P; Arslan, G; Haberal, M

2005-09-01

109

Estimation of cardiac output in patients with congestive heart failure by analysis of right ventricular pressure waveforms  

Microsoft Academic Search

Background  Cardiac output (CO) is an important determinant of the hemodynamic state in patients with congestive heart failure (CHF).\\u000a We tested the hypothesis that CO can be estimated from the right ventricular (RV) pressure waveform in CHF patients using\\u000a a pulse contour cardiac output algorithm that considers constant but patient specific RV outflow tract characteristic impedance.\\u000a \\u000a \\u000a \\u000a \\u000a Method  In 12 patients with CHF,

Mustafa Karamanoglu; Tom Bennett; Marcus Ståhlberg; Vincent Splett; Barbro Kjellström; Cecilia Linde; Frieder Braunschweig

2011-01-01

110

Comparison of Doppler flow Tei-indexes with pulmonary artery thermodilution measurement of cardiac output in an experimental porcine model.  

PubMed

The objective of our study was to compare Doppler echocardiography imaging with pulmonary artery thermodilution measurement during mechanical ventilation. Total 78 piglets (6 weeks old, average weight 24 kg, under general anesthesia) were divided into 4 groups under different cardiac loading conditions (at rest, with increased left ventricular afterload, with increased right ventricular preload, and with increased afterload of both heart ventricles). At 60 and 120 min the animals were examined by echocardiography and simultaneously pulmonary artery thermodilution was used to measure cardiac output. Tei-indexes data were compared with invasively monitored hemodynamic data and cardiac output values together with calculated vascular resistance indices. A total of 224 parallel measurements were obtained. Correlation was found between values of right Tei-index of myocardial performance and changes in right ventricular preload (p<0.05) and afterload (p<0.01). Significant correlation was also found between left index values and changes of left ventricular preload (p<0.001), afterload (p<0.001), stroke volume (p<0.01), and cardiac output (p<0.01). In conclusion, echocardiographic examination and determination of the global performance selectively for the right and left ventricle can be recommended as a suitable non-invasive supplement to the whole set of methods used for monitoring of circulation and cardiac performance. PMID:21401299

Kobr, J; T?eška, V; Molá?ek, J; Kuntscher, V; Liška, V; Slavík, Z

2011-01-01

111

Clinical evaluation of the flotrac/vigileo(TM) system for continuous cardiac output monitoring in patients undergoing regional anesthesia for elective cesarean section: a pilot study  

PubMed Central

BACKGROUND: Spinal anesthesia for cesarean delivery may cause severe maternal hypotension and a decrease in cardiac output. Compared to assessment of cardiac output via a pulmonary artery catheter, the FloTrac/Vigileo™ system may offer a less invasive technique. The aim of this study was to evaluate cardiac output and other hemodynamic measurements made using the FloTrac/Vigileo™ system in patients undergoing spinal anesthesia for elective cesarean section. METHODS: A prospective study enrolling 10 healthy pregnant women was performed. Hemodynamic parameters were continuously obtained at 15 main points: admission to surgery (two baseline measurements), after preload, after spinal anesthesia administration and 4 time points thereafter (4, 6, 8 and 10 min after anesthesia), at skin and uterine incision, newborn and placental delivery, oxytocin administration, end of surgery, and recovery from anesthesia. Hemodynamic therapy was guided by mean arterial pressure, and vasopressors were used as appropriate to maintain baseline values. A repeated measures ANOVA was used for data analysis. RESULTS: There was a significant increase in heart rate and a decrease of stroke volume and stroke volume index up to 10 min after spinal anesthesia (P < 0.01). Importantly, stroke volume variation increased immediately after newborn delivery (P < 0.001) and returned to basal values at the end of surgery. Further hemodynamic parameters showed no significant changes over time. DISCUSSION AND CONCLUSIONS: No significant hemodynamic effects, except for heart rate and stroke volume changes, were observed in pregnant women managed with preload and vasopressors when undergoing elective cesarean section and spinal anesthesia.

Auler, Jose Otavio C.; Torres, Marcelo L. A.; Cardoso, Monica M.; Tebaldi, Thais C.; Schmidt, Andre P.; Kondo, Mario M.; Zugaib, Marcelo

2010-01-01

112

Reduced peripheral arterial blood flow with preserved cardiac output during submaximal bicycle exercise in elderly heart failure  

Microsoft Academic Search

BACKGROUND: Older heart failure (HF) patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF) due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. METHODS AND RESULTS: Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF) (aged 68 ± 10 years)

Chirapa Puntawangkoon; Dalane W Kitzman; Stephen B Kritchevsky; Craig A Hamilton; Barbara Nicklas; Xiaoyan Leng; Peter H Brubaker; W Gregory Hundley

2009-01-01

113

The decreased oxygen uptake during progressive exercise in ischemia-induced heart failure is due to reduced cardiac output rate  

Microsoft Academic Search

We tested the hypothesis that the inability to increase cardiac output during exercise would explain the decreased rate of oxygen uptake (VO2) in recent onset, ischemia-induced heart failure rats. Nine nor- mal control rats and 6 rats with ischemic heart failure were studied. Myocardial infarction was induced by coronary ligation. VO2 was measured during a ramp protocol test on a

N. P. L. Rolim; K. C. Mattos; P. C. Brum; M. V. C. Baldo; H. R. Middlekauff; C. E. Negrão

2006-01-01

114

Cardiac Output Measurement in Patients Undergoing Liver Transplantation: Pulmonary Artery Catheter Versus Uncalibrated Arterial Pressure Waveform Analysis  

Microsoft Academic Search

BACKGROUND: Cardiac output (CO) and invasive hemodynamic measurements are useful during liver transplantation. The pulmonary artery catheter (PAC) is commonly used for these patients, despite the potential complications. Recently, a less invasive device (Vigileo®\\/FloTrac™) became available, which estimates CO using arterial pressure waveform analysis without external calibration. In this study, we compared CO obtained with a PAC using automatic thermodilution,

Biais Matthieu; Nouette-Gaulain Karine; Cottenceau Vincent; Vallet Alain; Cochard Jean François; Revel Philippe; Sztark François

2008-01-01

115

Pulmonary diffusing capacity, capillary blood volume, and cardiac output during sustained microgravity  

NASA Technical Reports Server (NTRS)

We measured pulmonary diffusing capacity (DL), diffusing capacity per unit lung volume, pulmonary capillary blood volume (Vc), membrane diffusing capacity (Dm), pulmonary capillary blood flow or cardiac output (Qc), and cardiac stroke volume (SV) in four subjects exposed to nine days of microgravity. DL in microgravity was elevated compared with preflight standing values and was higher than preflight supine because of the elevation of both Vc and Dm. The elevation in Vc was comparable to that measured supine in 1 G, but the increase in Dm was in sharp contrast to the supine value. We postulate that, in 0 G, pulmonary capillary blood is evenly distributed throughout the lung, providing for uniform capillary filling, leading to an increase in the surface area available for diffusion. By contrast, in the supine 1-G state, the capillaries are less evenly filled, and although a similar increase in blood volume is observed, the corresponding increase in surface area does not occur. DL and its subdivisions showed no adaptive changes from the first measurement 24 h after the start of 0 G to eight days later. Similarly, there were no trends in the postflight data, suggesting that the principal mechanism of these changes was gravitational. The increase in Dm suggests that subclinical pulmonary edema did not result from exposure to 0 G. Qc was modestly increased inflight and decreased postflight compared with preflight standing. Compared with preflight standing, SV was increased 46 percent inflight and decreased 14 percent in the 1st week postflight. There were temporal changes in Qc and SV during 0 G, with the highest values recorded at the first measurement, 24 h into the flight. The lowest values of Qc and SV occurred on the day of return.

Prisk, G. K.; Guy, Harold J. B.; Elliott, Ann R.; Deutschman, Robert A., III; West, John B.

1993-01-01

116

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.

Tuttle, Ann; Shore, Scott; Stone, Terry

2009-01-01

117

Downscaling NARCCAP Model Output for Local Level Impact Assessment  

NASA Astrophysics Data System (ADS)

There is a great societal interest in assessing the impacts of projected climate change on infrastructure design, such as of dams, bridges and coastal roads. Such impact assessment typically requires future projections of high-resolution time series of temperature, precipitation, solar radiation and related variables. We propose a methodology to downscale projected series from the NARCCAP regional climate model output to daily or hourly inputs at the local point scale. We focus on precipitation and extend the XCDF-T method of Kallache et al. to include estimation of precipitation return levels. We apply the method to locations of the NCDC monitoring network in the U.S. North Atlantic region using all available NARCCAP models. Different schemes for utilizing NARCCAP model output are tested and compared in terms of estimation precision, which is based on Bootstrap resampling.

Linder, E.

2012-12-01

118

Assessing industry linkages using regional input–output tables  

Microsoft Academic Search

Midmore P., Munday M. and Roberts A. (2006) Assessing industry linkages using regional Input–Output tables, Regional Studies40, 329–343. The regional policy literature has shown renewed interest in the promotion of industries with the potential to embed themselves into regional economies. Unfortunately, analysis of sectors within strategy-led documents often fails to tie the identification of key industries to any specific methodology.

Peter Midmore; Max Munday; Annette Roberts

2006-01-01

119

Cardiac output, at rest and during exercise, before and during myocardial ischemia, reperfusion, and infarction in conscious mice.  

PubMed

Multiple systems and regulatory strategies interact to control cardiac homeostasis. In fact, regulated systems, feedback controls, and redundant control mechanisms dominate in whole animals. Accordingly, molecular and cellular tools and techniques must be utilized in complex models with multiple systems and regulatory strategies to fully appreciate the physiological context. Currently, these techniques are mainly performed under conditions remote from the normal in vivo condition; thus, the extrapolation of molecular changes to the in vivo situation and the facilitation of translational aspect of the findings are limited. A major obstacle has been the reliance on preparations that do not mimic the clinical or physiological situation. This is particularly true regarding measurements of cardiac function in mice. To address these concerns, we used a permanently implanted Doppler ultrasonic flow probe on the ascending aorta and coronary artery occluder for repeated measurements of ascending aortic blood flow (cardiac output) in conscious mice, at rest and during exercise, before and during coronary artery occlusion/reperfusion and infarction. The conscious mouse model permits detailed monitoring of within-animal changes in cardiac function during myocardial ischemia, reperfusion, and infarction in an intact, complex model free of the confounding influences of anesthetics, surgical trauma, and restraint stress. Results from this study suggest that previous protocols may have overestimated resting baseline values and underestimated cardiac output reserve. Using these procedures in currently available spontaneous or engineered mouse mutants has the potential to be of major importance for advancing the concepts and methods that drive cardiovascular research. PMID:23302959

Lujan, Heidi L; DiCarlo, Stephen E

2013-02-15

120

Combined first pass and gated blood pool radionuclide studies in the hemodynamic-cardiac evaluation of patients with low cardiac output  

SciTech Connect

Cardiac output (CO) is frequently used in the evaluation of cardiac function but low CO does not necessarily reflect heart failure. Similarly, low ejection fraction (EF) can be present in compensated heart diseases. In order to evaluate cardiac performance in relation to systematic hemodynamics, the authors used a multifactorial approach for the determination of CO, EF, pulmonary mean transit time (MTT), ratio of cardiopulmonary volume over total blood volume (CPV/TBV as an index of venous tone) all obtained from a single injection of 99m Tc-HSA. Four different conditions associated with low CO (less than or equal to 2.1 L/min/m/sup 2/) were evaluated. The combined use of CO, EF, MTT and CPV/TBV allowed a better understanding of the myocardial and peripheral circulatory factors associated with low CO states. This is helpful in the selection and follow-up of appropriate therapeutic intervention.

Abi-Mansour, P.; Fouad, F.M.; Sheeler, L.R.; Bravo, E.L.; MacIntyre, W.J.; Tarazi, R.C.

1984-01-01

121

Semi-invasive monitoring of cardiac output by a new device using arterial pressure waveform analysis: a comparison with intermittent pulmonary artery thermodilution in patients undergoing cardiac surgery  

Microsoft Academic Search

Background. Thermodilution technique using a pulmonary artery catheter (PAC) is a widely used method to determine cardiac output (CO). It is increasingly criticized because of its inva- siveness and its unclear risk-benefit ratio. Thus, less invasive techniques for measuring CO are highly desirable. We compared a new, semi-invasive device (FloTrac\\/VigileoTM) using arterial pressure waveform analysis for CO measurement in patients

J. Mayer; J. Boldt; T. Schollhorn; K. D. Rohm; A. M. Mengistu; S. Suttner

2007-01-01

122

Use of cardiac output to improve measurement of input function in quantitative dynamic contrast-enhanced MRI  

PubMed Central

Purpose: To validate a new method for converting MR arterial signal intensity versus time curves to arterial input functions (AIF). Materials and Methods: The method constrains AIF with patient's cardiac output (Q). Monte Carlo simulations of MR renography and tumor perfusion protocols were carried out for comparison with two alternative methods: direct measurement and population-averaged input function. MR renography was performed to assess the method's inter- and intra-day reproducibility for renal parameters. Results: In simulations of tumor perfusion, the precision of the parameters (Ktrans and ve) computed using the proposed method was improved by at least a factor of three compared to direct measurement. Similar improvements were obtained in simulations of MR renography. Volunteer study for testing inter-day reproducibility confirmed the improvement of precision in renal parameters when using the proposed method, compared to conventional methods. In another patient study (two injections within one session), the proposed method significantly increased the correlation coefficient (R) between GFR of the two exams (0.92 vs. 0.83), compared to direct measurement. Conclusion: A new method significantly improves the precision of DCE parameters. The method may be especially useful for analyzing repeated DCE examinations, such as monitoring tumor therapy or ACE-inhibitor renography.

Zhang, Jeff L.; Rusinek, Henry; Bokacheva, Louisa; Chen, Qun; Storey, Pippa; Lee, Vivian S.

2009-01-01

123

Phlebotomy eliminates the maximal cardiac output response to six weeks of exercise training.  

PubMed

With this study we tested the hypothesis that 6 wk of endurance training increases maximal cardiac output (Q?max) relatively more by elevating blood volume (BV) than by inducing structural and functional changes within the heart. Nine healthy but untrained volunteers (V?o2max 47 ± 5 ml·min(-1)·kg(-1)) underwent supervised training (60 min; 4 times weekly at 65% V?o2max for 6 wk), and Q?max was determined by inert gas rebreathing during cycle ergometer exercise before and after the training period. After the training period, blood volume (determined in duplicates by CO rebreathing) was reestablished to pretraining values by phlebotomy and Q?max was quantified again. Resting echography revealed no structural heart adaptations as a consequence of the training intervention. After the training period, plasma volume (PV), red blood cell volume (RBCV), and BV increased (P < 0.05) by 147 ± 168 (5 ± 5%), 235 ± 64 (10 ± 3%), and 382 ± 204 ml (7 ± 4%), respectively. V?o2max was augmented (P < 0.05) by 10 ± 7% after the training period and decreased (P < 0.05) by 8 ± 7% with phlebotomy. Concomitantly, Q?max was increased (P < 0.05) from 18.9 ± 2.1 to 20.4 ± 2.3 l/min (9 ± 6%) as a consequence of the training intervention, and after normalization of BV by phlebotomy Q?max returned to pretraining values (18.1 ± 2.5 l/min; 12 ± 5% reversal). Thus the exercise training-induced increase in BV is the main mechanism increasing Q?max after 6 wk of endurance training in previously untrained subjects. PMID:24622974

Bonne, Thomas C; Doucende, Gregory; Flück, Daniela; Jacobs, Robert A; Nordsborg, Nikolai B; Robach, Paul; Walther, Guillaume; Lundby, Carsten

2014-05-15

124

The role of histamine in the increased cardiac output in hyperdynamic endotoxemia.  

PubMed

The role of histamine in the hyperdynamic circulatory response to endotoxin (ETX) was investigated in 32 anesthetized dogs by means of histamine H1- and H2-receptor blockade. A hyperdynamic circulation was elicited with a prolonged, slow infusion of a low dose of ETX, and hemodynamic parameters were examined in control and histamine receptor-blocked groups. The following groups were studied: Group ETX received a 2 h infusion of Escherichia coli 055:B5 endotoxin in a total dose of 13.75 micrograms/kg at a rate of 10 micrograms/kg for 45 min and then 5 micrograms/kg for 75 min. In addition to the same dose of ETX, Groups ETX+TPA and ETX+RAN received 0.5 mg/kg of the H1-blocker tripelennamine (TPA) or 2 mg/kg of the H2-blocker ranitidine (RAN), respectively. Infusion of ETX caused a moderate decrease in arterial pressure in Group ETX, whereas TPA but not RAN inhibited this pressure fall. The cardiac output (CO) increased by 41% above the baseline level in Group ETX. Both TPA and RAN prevented this rise in CO. The total peripheral resistance was considerably lowered by ETX, but this decrease was significantly attenuated in the TPA or RAN-treated groups. The heart rate rose significantly after ETX infusion and was unaffected by TPA or RAN. The stroke volume remained unchanged following ETX but was decreased both by TPA and by RAN. TPA or RAN, when given alone, did not affect any of the measured hemodynamic parameters. These experiments provide evidence of the participation of histamine in the hyperdynamic circulatory response in endotoxemia. PMID:7749934

Tárnoky, K; Tutsek, L; Nagy, S

1994-02-01

125

Mechanisms of increase in cardiac output during acute weightlessness in humans.  

PubMed

Based on previous water immersion results, we tested the hypothesis that the acute 0-G-induced increase in cardiac output (CO) is primarily caused by redistribution of blood from the vasculature above the legs to the cardiopulmonary circulation. In seated subjects (n = 8), 20 s of 0 G induced by parabolic flight increased CO by 1.7 ± 0.4 l/min (P < 0.001). This increase was diminished to 0.8 ± 0.4 l/min (P = 0.028), when venous return from the legs was prevented by bilateral venous thigh-cuff inflation (CI) of 60 mmHg. Because the increase in stroke volume during 0 G was unaffected by CI, the lesser increase in CO during 0 G + CI was entirely caused by a lower heart rate (HR). Thus blood from vascular beds above the legs in seated subjects can alone account for some 50% of the increase in CO during acute 0 G. The remaining increase in CO is caused by a higher HR, of which the origin of blood is unresolved. In supine subjects, CO increased from 7.1 ± 0.7 to 7.9 ± 0.8 l/min (P = 0.037) when entering 0 G, which was solely caused by an increase in HR, because stroke volume was unaffected. In conclusion, blood originating from vascular beds above the legs can alone account for one-half of the increase in CO during acute 0 G in seated humans. A Bainbridge-like reflex could be the mechanism for the HR-induced increase in CO during 0 G in particular in supine subjects. PMID:21636570

Petersen, Lonnie G; Damgaard, Morten; Petersen, Johan C G; Norsk, Peter

2011-08-01

126

Effects of ventilation on cardiac output determined by inert gas rebreathing.  

PubMed

One of the most important methodological problems of the foreign gas rebreathing technique is that outcome of the measurements depends on procedural variables such as rebreathing frequency (RF), rebreathing bag volume (V(reb)), lung volume at start of rebreathing and intervals between measurements. Therefore, in 10 healthy males we investigated the effects of changes in ventilation pattern on cardiac output (CO) estimated by an N(2)O-rebreathing technique. Reducing the rebreathing volume (V(reb)) from 1.5 to 1.0 l diminished CO by 0.5 +/- 0.2 l min(-1), whereas an increase in V(reb) from 1.5 to 2.5 l had no effects. CO was 1.0 +/- 0.2 l min(-1) higher when, rebreathing was performed after a forced expiration than following a normal tidal expiration. Serial determinations of CO required a 3-min interval between the measurements to avoid effects of recirculation of N(2)O. Changing RF from 15 to 30 breaths min(-1) or adding serial dead space by up to 600 ml did not affect the determination of CO. In conclusion, the rebreathing procedure for determination of CO at rest should be performed following a normal tidal expiration with a rebreathing bag volume of between 1.5 and 2.5 l and with manoeuvres separated by at least 3-5 min. Variations in RF within the physiological range from 15 to 30 breaths min(-1) do not affect outcome of the measurements. PMID:15888093

Damgaard, Morten; Norsk, Peter

2005-05-01

127

The Influence of Left Lateral Position on Cardiac Output Changes after Head Up Tilt Measured by Impedance Cardiography  

Microsoft Academic Search

Background.The value of the impedance cardiography (IC) method formeasuring cardiac output (CO) with the subject in the left lateral positionhas not yet been established. We compared the CO after a 30° head-up tiltwith the subjects in the supine and left lateral position. Methods.Thirty healthy young volunteers were placed in the supine horizontalposition. CO, stroke volume (SV) and heart rate (HR)

Mirt Kamenik

1999-01-01

128

High-output cardiac failure in a fetus with thanatophoric dysplasia associated with large placental chorioangioma: case report.  

PubMed

Placental chorioangioma is an angioma arising from chorionic tissue. Fetal thanatophoric dysplasia is a lethal skeletal dysplasia due to mutation of fibroblast growth factor receptor 3 gene. These two conditions are rare and their coexistence in a given fetus is even rarer. We present a case of a fetus with thanatophoric dysplasia having high-output cardiac failure due to a large placental chorioangioma. PMID:22508320

Akercan, Fuat; Oncul Seyfettinoglu, Sevtap; Zeybek, Burak; Cirpan, Teksin

2012-05-01

129

Non-invasive measurement of cardiac output in heart failure patients using a new foreign gas rebreathing technique.  

PubMed

Values of effective pulmonary blood flow (Q(EP)) and cardiac output, determined by a non-invasive foreign gas rebreathing method (CO(RB)) using a new infrared photoacoustic gas analysing system, were compared with measurements of cardiac output obtained by the direct Fick (CO(FICK)) and thermodilution (CO(TD)) methods in patients with heart failure or pulmonary hypertension. In 11 patients, of which three had shunt flow through areas without significant gas exchange, the mean difference (bias) and limits of agreement (+/- 2 S.D.) were 0.6 +/- 1.2 litre x min(-1) when comparing CO(FICK) and Q(EP), and -0.8 +/- 1.3 litre x min(-1) when comparing CO(FICK) and CO(TD). When correction for intrapulmonary shunt flow was applied (i.e. calculation of CO(RB)) in all 11 patients, the bias between CO(FICK) and CO(RB) was 0.1 +/- 0.9 litre x min(-1), primarily because agreement improved in the three patients with significant shunt flow. In the eight patients without significant shunt flow, the agreement between Q(EP) and CO(FICK) was 0.3 +/- 0.9 litre x min(-1). In conclusion, a foreign gas rebreathing method with a new infrared photoacoustic gas analyser provided at least as reliable a measure of cardiac output as did thermodilution. In the absence of significant shunt flow, measurement of Q(EP) itself provides a reliable estimate of cardiac output in heart failure patients. The infrared photoacoustic gas analyser markedly facilitates clinical use of the rebreathing method in general, which makes the method available to a larger group of clinicians working with patients with cardiovascular diseases. PMID:11834145

Gabrielsen, Anders; Videbaek, Regitze; Schou, Morten; Damgaard, Morten; Kastrup, Jens; Norsk, Peter

2002-02-01

130

Venoarterial PCO2 difference: a marker of postoperative cardiac output in children with congenital heart disease  

Microsoft Academic Search

OBJECTIVE: To determine the relationship between venoarterial carbon dioxide gradient (DeltapCO2) and central venous oxygen saturation (ScvO2) in children after cardiac surgery.STUDY DESIGN: A cohort study.PLACE AND DURATION OF STUDY: The Paediatric cardiac intensive care unit of the Aga Khan University Hospital, Karachi, from June 2006 to May 2007.METHODOLOGY: All children admitted in the paediatric cardiac intensive care after complete

Muhammad Furqan; Fahad Hashmat; Munir Amanullah; Mansoor Khan; Hina K Durani; Anwar-ul-Haque

2009-01-01

131

Evaluation of cardiac output in intensive care using a non-invasive arterial pulse contour technique (Nexfin(®)) compared with echocardiography.  

PubMed

In this prospective study, cardiac output was measured in 38 intensive care unit patients before and after a fluid challenge, using both pulse contour analysis (Nexfin(®); BMEYE, Amsterdam, the Netherlands) and transthoracic echocardiography. The ability of the Nexfin device to detect significant changes in the velocity-time integral was evaluated. The pulse wave could not be detected by the Nexfin device in five patients (13%), leaving 33 patients for analysis. The Nexfin device adequately tracked changes in the velocity-time integral in 20 (61%) patients. Using a cut-off of a 10% increase in cardiac output estimated by the Nexfin or by echocardiography, the sensitivity of the Nexfin device to detect a response to fluid challenge was 47%, with specificity 81% and accuracy 64%. The percentage error between the Nexfin and echocardiography was 448%; lower limit of agreement -48% (95% CI -62 to -36%) and upper limit of agreement, 32% (95% CI 20-45%). We conclude that the Nexfin device does not adequately track changes in cardiac output in critically ill patients. PMID:23837860

Taton, O; Fagnoul, D; De Backer, D; Vincent, J-L

2013-09-01

132

The effect of bundle branch block on heart function and cardiac output in premature infant.  

PubMed

It is well known that hyperkalemia may cause arrhythmia, right bundle branch block, and cardiac conduction block. These dysrhythmias have the potential to affect cardiac function. We present a premature newborn with hyperkalemia and right bundle branch block causing left ventricular dyssynchrony with mitral regurgitation, which led to decreased pump function. PMID:23604222

Jawa, Gaurav; Yuen, Doris; Norozi, Kambiz

2013-12-01

133

Diesel Exhaust Inhalation Increases Cardiac Output, Bradyarrhythmias, and Parasympathetic Tone in Aged Heart Failure-Prone Rats  

PubMed Central

Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel engine exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance of normal cardiac function. To explore this putative mechanism, we examined cardiophysiologic responses to DE inhalation in a model of aged heart failure–prone rats without signs or symptoms of overt heart failure. We hypothesized that acute DE exposure would alter heart rhythm, cardiac electrophysiology, and ventricular performance and dimensions consistent with autonomic imbalance while increasing biochemical markers of toxicity. Spontaneously hypertensive heart failure rats (16 months) were exposed once to whole DE (4h, target PM2.5 concentration: 500 µg/m3) or filtered air. DE increased multiple heart rate variability (HRV) parameters during exposure. In the 4h after exposure, DE increased cardiac output, left ventricular volume (end diastolic and systolic), stroke volume, HRV, and atrioventricular block arrhythmias while increasing electrocardiographic measures of ventricular repolarization (i.e., ST and T amplitudes, ST area, T-peak to T-end duration). DE did not affect heart rate relative to air. Changes in HRV positively correlated with postexposure changes in bradyarrhythmia frequency, repolarization, and echocardiographic parameters. At 24h postexposure, DE-exposed rats had increased serum C-reactive protein and pulmonary eosinophils. This study demonstrates that cardiac effects of DE inhalation are likely to occur through changes in autonomic balance associated with modulation of cardiac electrophysiology and mechanical function and may offer insights into the adverse health effects of traffic-related air pollutants.

Farraj, Aimen K.

2013-01-01

134

Diesel exhaust inhalation increases cardiac output, bradyarrhythmias, and parasympathetic tone in aged heart failure-prone rats.  

PubMed

Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel engine exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance of normal cardiac function. To explore this putative mechanism, we examined cardiophysiologic responses to DE inhalation in a model of aged heart failure-prone rats without signs or symptoms of overt heart failure. We hypothesized that acute DE exposure would alter heart rhythm, cardiac electrophysiology, and ventricular performance and dimensions consistent with autonomic imbalance while increasing biochemical markers of toxicity. Spontaneously hypertensive heart failure rats (16 months) were exposed once to whole DE (4h, target PM(2.5) concentration: 500 µg/m(3)) or filtered air. DE increased multiple heart rate variability (HRV) parameters during exposure. In the 4h after exposure, DE increased cardiac output, left ventricular volume (end diastolic and systolic), stroke volume, HRV, and atrioventricular block arrhythmias while increasing electrocardiographic measures of ventricular repolarization (i.e., ST and T amplitudes, ST area, T-peak to T-end duration). DE did not affect heart rate relative to air. Changes in HRV positively correlated with postexposure changes in bradyarrhythmia frequency, repolarization, and echocardiographic parameters. At 24h postexposure, DE-exposed rats had increased serum C-reactive protein and pulmonary eosinophils. This study demonstrates that cardiac effects of DE inhalation are likely to occur through changes in autonomic balance associated with modulation of cardiac electrophysiology and mechanical function and may offer insights into the adverse health effects of traffic-related air pollutants. PMID:23047911

Carll, Alex P; Lust, Robert M; Hazari, Mehdi S; Perez, Christina M; Krantz, Quentin Todd; King, Charly J; Winsett, Darrell W; Cascio, Wayne E; Costa, Daniel L; Farraj, Aimen K

2013-02-01

135

Early non-invasive cardiac output monitoring in hemodynamically unstable intensive care patients: A multi-center randomized controlled trial  

PubMed Central

Introduction Acute hemodynamic instability increases morbidity and mortality. We investigated whether early non-invasive cardiac output monitoring enhances hemodynamic stabilization and improves outcome. Methods A multicenter, randomized controlled trial was conducted in three European university hospital intensive care units in 2006 and 2007. A total of 388 hemodynamically unstable patients identified during their first six hours in the intensive care unit (ICU) were randomized to receive either non-invasive cardiac output monitoring for 24 hrs (minimally invasive cardiac output/MICO group; n = 201) or usual care (control group; n = 187). The main outcome measure was the proportion of patients achieving hemodynamic stability within six hours of starting the study. Results The number of hemodynamic instability criteria at baseline (MICO group mean 2.0 (SD 1.0), control group 1.8 (1.0); P = .06) and severity of illness (SAPS II score; MICO group 48 (18), control group 48 (15); P = .86)) were similar. At 6 hrs, 45 patients (22%) in the MICO group and 52 patients (28%) in the control group were hemodynamically stable (mean difference 5%; 95% confidence interval of the difference -3 to 14%; P = .24). Hemodynamic support with fluids and vasoactive drugs, and pulmonary artery catheter use (MICO group: 19%, control group: 26%; P = .11) were similar in the two groups. The median length of ICU stay was 2.0 (interquartile range 1.2 to 4.6) days in the MICO group and 2.5 (1.1 to 5.0) days in the control group (P = .38). The hospital mortality was 26% in the MICO group and 21% in the control group (P = .34). Conclusions Minimally-invasive cardiac output monitoring added to usual care does not facilitate early hemodynamic stabilization in the ICU, nor does it alter the hemodynamic support or outcome. Our results emphasize the need to evaluate technologies used to measure stroke volume and cardiac output--especially their impact on the process of care--before any large-scale outcome studies are attempted. Trial Registration The study was registered at ClinicalTrials.gov (Clinical Trials identifier NCT00354211)

2011-01-01

136

Pulmonary Artery Catheter (PAC) Accuracy and Efficacy Compared with Flow Probe and Transcutaneous Doppler (USCOM): An Ovine Cardiac Output Validation  

PubMed Central

Background. The pulmonary artery catheter (PAC) is an accepted clinical method of measuring cardiac output (CO) despite no prior validation. The ultrasonic cardiac output monitor (USCOM) is a noninvasive alternative to PAC using Doppler ultrasound (CW). We compared PAC and USCOM CO measurements against a gold standard, the aortic flow probe (FP), in sheep at varying outputs. Methods. Ten conscious sheep, with implanted FPs, had measurements of CO by FP, USCOM, and PAC, at rest and during intervention with inotropes and vasopressors. Results. CO measurements by FP, PAC, and USCOM were 4.0 ± 1.2?L/min, 4.8 ± 1.5?L/min, and 4.0 ± 1.4?L/min, respectively, (n = 280, range 1.9?L/min to 11.7?L/min). Percentage bias and precision between FP and PAC, and FP and USCOM was ?17 and 47%, and 1 and 36%, respectively. PAC under-measured Dobutamine-induced CO changes by 20% (relative 66%) compared with FP, while USCOM measures varied from FP by 3% (relative 10%). PAC reliably detected ?30% but not +40% CO changes, as measured by receiver operating characteristic area under the curve (AUC), while USCOM reliably detected ±5% changes in CO (AUC > 0.70). Conclusions. PAC demonstrated poor accuracy and sensitivity as a measure of CO. USCOM provided equivalent measurements to FP across a sixfold range of outputs, reliably detecting ±5% changes.

Phillips, Robert A.; Hood, Sally G.; Jacobson, Beverley M.; West, Malcolm J.; Wan, Li; May, Clive N.

2012-01-01

137

Glucagon-like peptide-1 (7-36) but not (9-36) augments cardiac output during myocardial ischemia via a Frank-Starling mechanism.  

PubMed

This study examined the cardiovascular effects of GLP-1 (7-36) or (9-36) on myocardial oxygen consumption, function and systemic hemodynamics in vivo during normal perfusion and during acute, regional myocardial ischemia. Lean Ossabaw swine received systemic infusions of saline vehicle or GLP-1 (7-36 or 9-36) at 1.5, 3.0, and 10.0 pmol/kg/min in sequence for 30 min at each dose, followed by ligation of the left circumflex artery during continued infusion at 10.0 pmol/kg/min. Systemic GLP-1 (9-36) had no effect on coronary flow, blood pressure, heart rate or indices of cardiac function before or during regional myocardial ischemia. Systemic GLP-1 (7-36) exerted no cardiometabolic or hemodynamic effects prior to ischemia. During ischemia, GLP-1 (7-36) increased cardiac output by approximately 2 L/min relative to vehicle-controls (p = 0.003). This response was not diminished by treatment with the non-depolarizing ganglionic blocker hexamethonium. Left ventricular pressure-volume loops measured during steady-state conditions with graded occlusion of the inferior vena cava to assess load-independent contractility revealed that GLP-1 (7-36) produced marked increases in end-diastolic volume (74 ± 1 to 92 ± 5 ml; p = 0.03) and volume axis intercept (8 ± 2 to 26 ± 8; p = 0.05), without any change in the slope of the end-systolic pressure-volume relationship vs. vehicle during regional ischemia. GLP-1 (9-36) produced no changes in any of these parameters compared to vehicle. These findings indicate that short-term systemic treatment with GLP-1 (7-36) but not GLP-1 (9-36) significantly augments cardiac output during regional myocardial ischemia, via increases in ventricular preload without changes in cardiac inotropy. PMID:25005062

Goodwill, Adam G; Tune, Johnathan D; Noblet, Jillian N; Conteh, Abass M; Sassoon, Daniel; Casalini, Eli D; Mather, Kieren J

2014-09-01

138

Effect of hemorrhage on cardiac output, vasopressin, aldosterone, and diuresis during immersion in men  

NASA Technical Reports Server (NTRS)

The purpose of this research was to test the hypotesis that a reduction in blood volume would attenuate or eliminate immersion-induced increases in cardiac output (Q(sub co)) and urine excretion, and to investigate accompanying vasoactive and fluid-electrolyte hormonal responses. Eight men (19-23 yr) were supine during a 2-hr control period in air, and then sat for 5-hr test periods in air at 20 C (dry control, DC); water at 34.5 C (wet control, WC); and water (34.5 C) after hemorrhage (WH) of 14.8 plus or minus 0.3 percent of their blood volume. Blood volume was -11.6 plus or minus 0.6 percent at immersion (time 0). Mean (bar-X hrs 1-5) Q(sub co) was unchanged in WC (5.3 plus or minus 0.01 l/min) and in WH (4.5 plus or minus 0.1 l/min), but decreased (P less than 0.05) in DC to 3.6 plus or minus 0.1 l/min. Mean urine excretion rates were 1.0 plus or minus 0.2 ml/min for DC and 1.1 plus or minus 0.2 ml/min for WH; both were lower (P less than 0.05) than that for WC of 2.0 plus or minus 0.4 ml/min. Plasma (Na+) and (Osm) were unchanged in all experiments. Mean plasma vasopressin (PVP) (bar-X hrs 1-5) was 1.1 plus or minus 0.1 pg/ml in WC, and higher (P less than 0.05) in DC (2.1 plus or minus 0.2 pg/ml)and WH (2.1 plus or minus 0.1 pg/ml); it was unchanged during air and water test periods. Thus, hemorrhage attenuated the immersion-induced increase in Q(sub co), eliminated the WC diuresis, maintained plasma renin activity and PVP at DC levels and did not change immersion-induced aldosterone suppression; the osmotic diuresis during control immersion is apparently not due to either aldosterone suppression or vasopressin suppression.

Greenleaf, J. E.; Simanonok, K.; Bernauer, E. M.; Wade, C. E.; Keil, L. C.

1992-01-01

139

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

140

Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement  

NASA Astrophysics Data System (ADS)

The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

Soukup, Ladislav; Vondra, Vlastimil; Viš?or, Ivo; Jurák, Pavel; Halámek, Josef

2013-04-01

141

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

142

Cardiac assessment of African hedgehogs (Atelerix albiventris).  

PubMed

Cardiomyopathy is a common finding in captive African hedgehogs (Atelerix albiventris) at postmortem exam. To date, treatment attempts have been mostly empirical and unrewarding. The objective of this study was to determine reference cardiac values for captive African hedgehogs based on echocardiogram, electrocardiogram (ECG), and radiographs. Adult African hedgehogs with no clinical signs of cardiac disease (n = 13) were selected. Each animal was anesthetized with isoflurane via facemask and an echocardiogram, ECG, and radiographs were performed. Standard measurements were taken and the descriptive statistics performed. Values were comparable to limited data available in other hedgehog species and other similar-sized exotic species. Two animals were removed from consideration of reference values due to valvular defects that were considered significant. These data are the first establishing cardiac parameters in normal African hedgehogs using radiographic cardiac measurement, echocardiogram, and ECG. Evaluating animals with possible cardiomyopathy may allow for earlier diagnosis and more successful treatment. PMID:22946370

Black, Peter A; Marshall, Cecilia; Seyfried, Alice W; Bartin, Anne M

2011-03-01

143

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

144

Reliability of continuous cardiac output measurement during intra-abdominal hypertension relies on repeated calibrations: an experimental animal study  

PubMed Central

Introduction Monitoring cardiac output (CO) may allow early detection of haemodynamic instability, aiming to reduce morbidity and mortality in critically ill patients. Continuous cardiac output (CCO) monitoring is recommended in septic or postoperative patients with high incidences of intra-abdominal hypertension (IAH). The aim of the present study was to compare the agreement between three CCO methods and a bolus thermodilution CO technique during acute IAH and volume loading. Methods Ten pigs were anaesthetised and instrumented for haemodynamic measurements. Cardiac output was obtained using CCO by pulse power analysis (PulseCO; LiDCO monitor), using CCO by pulse contour analysis (PCCO; PiCCO monitor) and using CCO by pulmonary artery catheter thermodilution (CCOPAC), and was compared with bolus transcardiopulmonary thermodilution CO (COTCP) at baseline, after fluid loading, at IAH and after an additional fluid loading at IAH. Whereas PulseCO was only calibrated at baseline, PCCO was calibrated at each experimental step. Results PulseCO and PCCO underestimated CO, as the overall bias ± standard deviation was 1.0 ± 1.5 l/min and 1.0 ± 1.1 l/min compared with COTCP. A clinically accepted agreement between all of the CCO methods and COTCP was observed only at baseline. Whereas IAH did not influence the CO, increased CO following fluid loading at IAH was only reflected by CCOPAC and COTCP, not by uncalibrated PulseCO and PCCO. After recalibration, PCCO was comparable with COTCP. Conclusions The CO obtained by uncalibrated PulseCO and PCCO failed to agree with COTCP during IAH and fluid loading. In the critically ill patient, recalibration of continuous arterial waveform CO methods should be performed after fluid loading or before a major change in therapy is initiated.

Gruenewald, Matthias; Renner, Jochen; Meybohm, Patrick; Hocker, Jan; Scholz, Jens; Bein, Berthold

2008-01-01

145

Numerical observer for cardiac motion assessment using machine learning  

NASA Astrophysics Data System (ADS)

In medical imaging, image quality is commonly assessed by measuring the performance of a human observer performing a specific diagnostic task. However, in practice studies involving human observers are time consuming and difficult to implement. Therefore, numerical observers have been developed, aiming to predict human diagnostic performance to facilitate image quality assessment. In this paper, we present a numerical observer for assessment of cardiac motion in cardiac-gated SPECT images. Cardiac-gated SPECT is a nuclear medicine modality used routinely in the evaluation of coronary artery disease. Numerical observers have been developed for image quality assessment via analysis of detectability of myocardial perfusion defects (e.g., the channelized Hotelling observer), but no numerical observer for cardiac motion assessment has been reported. In this work, we present a method to design a numerical observer aiming to predict human performance in detection of cardiac motion defects. Cardiac motion is estimated from reconstructed gated images using a deformable mesh model. Motion features are then extracted from the estimated motion field and used to train a support vector machine regression model predicting human scores (human observers' confidence in the presence of the defect). Results show that the proposed method could accurately predict human detection performance and achieve good generalization properties when tested on data with different levels of post-reconstruction filtering.

Marin, Thibault; Kalayeh, Mahdi M.; Pretorius, P. H.; Wernick, Miles N.; Yang, Yongyi; Brankov, Jovan G.

2011-03-01

146

Prevalence of nursing diagnosis of decreased cardiac output and the predictive value of defining characteristics in patients under evaluation for heart transplant.  

PubMed

The purposes of the study were to identify the prevalence of defining characteristics (DC) of decreased cardiac output (DCO) in patients with cardiac insufficiency under evaluation for heart transplantation, and to ascertain the likelihood of defining characteristics being predictive factors for the existence of reduction in cardiac output. Data was obtained by retrospective documental analysis of the clinical records of right-sided heart catheterizations in 38 patients between 2004 and 2009. The results showed that 71.1% of the patients had decreased cardiac output (measured by cardiac index). The majority of the NANDA-International defining characteristics for DCO were more frequent in individuals with reduced cardiac index levels. The study emphasizes the odds ratio (OR) for increased Systemic Vascular Resistance of OR=4.533, of the third heart sound with OR=3.429 and the reduced ejection fraction with OR=2.850. By obtaining the predictive values for the defining characteristics the study identifies them as diagnostic indicators of decreased cardiac output. PMID:22699731

Matos, Lígia Neres; Guimarães, Tereza Cristina Felippe; Brandão, Marcos Antônio Gomes; Santoro, Deyse Conceição

2012-01-01

147

[Effects of cardiac output on PETCO2 and PaCO2 during combined inhalational-epidural anesthesia].  

PubMed

We investigated the effects of cardiac output on PETCO2 in anesthetized patients. We studied 8 adult patients undergoing long-lasting lower abdominal surgery. Anesthesia was maintained with epidural combined with inhalational anesthesia. The minute ventilation volume was kept constant at 10 ml.kg-1 x 10 cycles.min-1. PETCO2, PaCO2, and cardiac index, (CI) by thermodilution method were measured simultaneously. PaCO2 was corrected for body temperature for comparison with PETCO2. Approximate value of alveolar dead space to tidal volume ratio was calculated as VD/ VTalv = (PaCO2-PETCO2)/PaCO2. The measurements were repeated every 10 to 20 minutes under the steady body temperature. One hundred and six sets of data were obtained from these patients. PETCO2 as well as PaCO2 correlated positively with CI, while VD/VTalv did not correlate with CI. PETCO2 correlated positively with PaCO2, while it did not correlate with VD/VTa1v. When examined in individual patients, PETCO2 correlated positively with CI in 7 patients. PaCO2 correlated positively with CI in 6 patients, while VD/VTa1v correlated negatively with CI only in 2 patients, in whom CI showed a large fluctuation. PaCO2 correlated positively with PETCO2 in 8 patient, while VD/VTa1v correlated negatively with PETCO2 only in 1 patient. By multiple regression analysis, VD/VTa1v change accounted for only 20.0 +/- 15.3% of PETCO2 change, while PACO2 or PaCO2 change accounted for 79.3 +/- 16.7%. Decreased CI was associated with a decrease in oxygen uptake (VO2), and PaCO2 correlated positively with VO2. Decreased CI was also associated with an increase in VA/Q, and PaCO2 correlated negatively with VA/Q. Thus, PETCO2 decreased with decreasing cardiac output. A decrease in PACO2 explained the decrease in PETCO2 better than an increase in VD/VT did. Decreased cardiac output caused hypocapnia through decreased CO2 production and/or increased ventilation to perfusion ratio i.e. relative hyperventilation. PMID:9369041

Hayashida, M; Orii, R; Komatsu, K; Chinzei, M; Nakagawa, Y; Nishiyama, T; Suwa, K; Hanaoka, K

1997-10-01

148

Protein kinase C depresses cardiac myocyte power output and attenuates myofilament responses induced by protein kinase A  

PubMed Central

Following activation by G-protein-coupled receptor agonists, protein kinase C (PKC) modulates cardiac myocyte function by phosphorylation of intracellular targets including myofilament proteins cardiac troponin I (cTnI) and cardiac myosin binding protein C (cMyBP-C). Since PKC phosphorylation has been shown to decrease myofibril ATPase activity, we hypothesized that PKC phosphorylation of cTnI and cMyBP-C will lower myocyte power output and, in addition, attenuate the elevation in power in response to protein kinase A (PKA)-mediated phosphorylation. We compared isometric force and power generating capacity of rat skinned cardiac myocytes before and after treatment with the catalytic subunit of PKC. PKC increased phosphorylation levels of cMyBP-C and cTnI and decreased both maximal Ca2+ activated force and Ca2+ sensitivity of force. Moreover, during submaximal Ca2+ activations PKC decreased power output by 62 %, which arose from both the fall in force and slower loaded shortening velocities since depressed power persisted even when force levels were matched before and after PKC. In addition, PKC blunted the phosphorylation of cTnI by PKA, reduced PKA-induced spontaneous oscillatory contractions, and diminished PKA-mediated elevations in myocyte power. To test whether altered thin filament function plays an essential role in these contractile changes we investigated the effects of chronic cTnI pseudo-phosphorylation on myofilament function using myocyte preparations from transgenic animals in which either only PKA phosphorylation sites (Ser-23/Ser-24) (PP) or both PKA and PKC phosphorylation sites (Ser-23/Ser-24/Ser-43/Ser-45/T-144) (All-P) were replaced with aspartic acid. Cardiac myocytes from All-P transgenic mice exhibited reductions in maximal force, Ca2+ sensitivity of force, and power. Similarly diminished power generating capacity was observed in hearts from All-P mice as determined by in situ pressure–volume measurements. These results imply that PKC-mediated phosphorylation of cTnI plays a dominant role in depressing contractility, and, thus, increased PKC isozyme activity may contribute to maladaptive behavior exhibited during the progression to heart failure.

Hinken, Aaron C.; Hanft, Laurin M.; Scruggs, Sarah B.; Sadayappan, Sakthivel; Robbins, Jeffery; Solaro, R. John

2013-01-01

149

Comparing two life cycle assessment approaches: a process model vs. economic input-output-based assessment  

Microsoft Academic Search

We compare two tools for Life Cycle Assessment (LCA). The software GaBi (Ganzheitliche Bilanzierung Integrated Assessment) from Germany is based on a process model approach, as recommended by the Society of Environmental Toxicology and Chemistry (SETAC). These results are contrasted to those from the method developed by Carnegie Mellon University's Green Design Initiative, Economic Input-Output Life Cycle Analysis (EIO-LCA). The

Chris T. Hendrickson; Arpad Horvath; Satish Joshi; M. Klausner; L. B. Lave; F. C. McMichael

1997-01-01

150

Short term correction of anaemia with recombinant human erythropoietin and reduction of cardiac output in end stage renal failure.  

PubMed Central

Children with end stage renal failure and anaemia have an increased cardiac index and often gross ventricular hypertrophy. The contribution of anaemia to these abnormalities is uncertain. Eleven children with end stage renal failure and anaemia (haemoglobin concentration < 90 g/l) were enrolled into a single blind, placebo controlled, crossover study to assess the cardiovascular effects of reversing anaemia using subcutaneous human recombinant erythropoietin (r-HuEpo). Each limb lasted 24 weeks; seven children completed both limbs of the study. Haemoglobin increased with r-HuEpo, remaining above 100 g/l for a mean of 11 weeks. Cardiac index fell as a result of a reduction in both left ventricular stroke volume and heart rate. Left ventricular end diastolic diameter also decreased. In five children left ventricular wall thickness and left ventricular mass decreased with r-HuEpo, but this failed to reach significance for the whole group. Blood pressure did not change in six normotensive children completing an r-HuEpo limb; the decrease in cardiac index was therefore balanced by an increase in peripheral vascular resistance. Three children were taking anti-hypertensive treatment at the start of the study; one required an increase, and one a decrease, in treatment during the r-HuEpo limb. Short term treatment with r-HuEpo reduces cardiac index. A longer study is needed to determine whether this will, in time, result in a significant reduction in left ventricular hypertrophy.

Morris, K P; Skinner, J R; Hunter, S; Coulthard, M G

1993-01-01

151

Assessing the Cardiac Toxicity of Chemotherapeutic Agents: Role of Echocardiography  

PubMed Central

Advancements in cancer treatment have resulted in sufficient survival length for patients to experience treatment-related cardiac complications. In particular, chemotherapy-induced cardiac dysfunction significantly impacts morbidity and mortality rates in cancer patients. The presence of cardiotoxicity from chemotherapy has been traditionally assessed using clinical symptoms and decreases in left ventricular ejection fraction (LVEF). However, in this indication, LVEF lacks accuracy as a measure of subclinical cardiotoxicity and its prognostic value is controversial. There is an emphasis to identify subclinical and left ventricular dysfunction early, in order to allow cancer patients and their physicians to make informed decisions about therapeutic options. Echocardiography is a readily available noninvasive tool to measure cardiac function and plays a major role in the diagnosis of cardiotoxicity. This review focuses on the role of echocardiography in detecting cardiotoxicity, and will discuss conventional and more recent echocardiographic approaches for assessing subclinical cardiotoxicity.

Tan, Timothy C.

2012-01-01

152

[Heart size and left ventricular function in coronary artery disease: I. Heart size, exercise tolerance, cardiac output and filling pressures (author's transl)].  

PubMed

The possible relationship between the cardiac volume, as determined radiologically in the supine position in 119 patients with angiographically proven coronary artery disease, and the results of ergometry and balloon catheterization was investigated. There was no relationship between the heart size on the one side and the maximum exercise tolerance and the maximum cardiac output on the other, except for the fact, that these parameters tended to decrease with increasing heart size. This was especially true in patients with angina. The maximum cardiac output of patients with angina was always below the value of patients without angina but comparable heart size. Reduced cardiac output under exercise (exertional cardiac insufficiency) was present in 50% of patients with enlarged hearts but already in 22% of patients with heart volumes in the lower range of normal. The diastolic pulmonary artery pressure, determined under exercise, was the only parameter with a significant relationship to the heart size: The larger the heart size, the higher the diastolic pulmonary artery pressure. On the other hand: the diastolic pulmonary artery pressure at rest was abnormal with significant frequency only, when the heart was enlarged. Our data suggest, that the hemodynamics are determined by 2 factors: Myocardial scarring secondary to infarction and coronary insufficiency (ischemia). Of these two factors only the former influences cardiac size. Therefore, determination of the heart volume helps evaluating the respective role of these two factors in individual cases. PMID:927289

Meuret, G; Jaedicke, W; Barmeyer, J; Wink, K; König, K; Reindell, H

1977-11-01

153

The contribution of alterations in cardiac output to changes in arterial pressure reflexly evoked from the carotid sinus in the rabbit.  

PubMed Central

1. The reflex cardiovascular effects of changes in pressure within the vascularly isolated carotid sinus were examined in seventeen anaesthetized rabbits. The opposite sinus was denervated and both aortic nerves were divided, 2. Comparison of the mean values at sinus pressures of 40 and 200 mmHg showed a large reduction in systemic arterial pressure from 126 to 58 mmHg and a moderate reduction in heart rate, from 287 to 253 beats min-1. Cardiac output, measured by thermal dilution, showed only a small change, a fall from 160 to 148 ml. min-1 kg-1. 3. By contrast with this reduction in cardiac output of just over 7%, total peripheral resistance, derived by dividing mean arterial pressure by cardiac output, was halved, falling from 0-48 to 0-41 mmHg ml.-1 min kg. 4. Thus in the anaesthetized rabbit changes in cardiac output make only a small contribution to the changes in systemic pressure evoked by alterations in carotid sinus pressure. Changes in total peripheral resistance are principally responsible for the effect on systemic pressure. 5. Though the changes in output of the heart were small, there were considerable changes in the work done by the left ventricle which was approximately halved when carotid sinus pressure was raised from 40 to 200 mmHg.

Humphreys, P W; Joels, N

1977-01-01

154

GH dependence and GH withdrawal syndrome in GH treatment of short normal children: evidence from growth and cardiac output.  

PubMed

The child's age is a significant determinant of the outcome of GH therapy; prepubertal children respond better on both short term and long term growth, whereas adolescents tend to accelerate their bone maturation more than growth. The present study was designed to evaluate the efficacy of an interrupted GH therapy protocol of young, short normal children. GH was given for a period of 3 years, or until they reached the 25th percentile, then discontinued at a young age (not more than 9 years), and then the children's growth followed until final height. Yet, after discontinuation of GH therapy, growth came close to a complete stand-still. The present report focuses on describing the period beyond GH withdrawal and its impact on growth and cardiac performance. Twenty-two children received daily s.c. injections of 0.9 mg/m2 hGH and 12 children were the control, untreated group. Growth and echocardiography were followed during therapy and 2 years thereafter. During GH treatment growth velocity accelerated markedly over the first year; it slowed down over the second and third years, and decelerated after GH withdrawal to a velocity that was significantly lower than pretreatment values. Growth rate remained low for the next year, and recovered to pretreatment velocity by the fourth semiannual measurement. To evaluate the role of the GH-IGF-I axis during the growth deceleration, serum IGF-I, insulin-like growth factor-binding protein-3 (IGFBP-3), and an arginine stimulation test were performed at 1, 3 or 6 months after GH withdrawal, and compared with pretreatment response. GH response was 70% of pretreatment values by 1 month and recovered completely by 3 months post treatment. Serum IGF-I and IGFBP-3 levels were normal throughout. End-systolic and end-diastolic left ventricular dimensions as well as cardiac output did not change during the 2 year course of GH therapy, but fell significantly during the initial 6 months of GH withdrawal. Thus, daily injections of GH to prepubertal short normal children is associated with development of drug dependence, followed during the abstinence period by deceleration of growth and reduction of cardiac output to levels that are lower than pretreatment values. After GH therapy for 30-36 months the withdrawal syndrome persists for 18 months, and is not induced by alterations of serum levels of GH or IGF-I. PMID:9578507

Lampit, M; Lorber, A; Vilkas, D L; Nave, T; Hochberg, Z

1998-04-01

155

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

PubMed Central

Cardiovascular disease (CVD) is associated with cognitive deficits even in the absence of stroke. We examined the relationship between cardiac performance, as measured by cardiac output (CO) and ejection fraction (EF), and brain activity during a verbal working memory (VWM) task in elderly CVD patients who tend to be at increased risk for vascular cognitive impairments. Seventeen patients were recruited from a cohort participating in an ongoing prospective study examining the effects of CVD on cognitive function in the elderly. Participants were diagnosed with CVD (age 68±8) and completed a 2-back VWM task in a 1.5T fMRI paradigm. CO and EF were calculated from echocardiogram measures. Task-related activation was averaged in a priori regions of interest. The relationship between CO, EF, and 2-back-related activity was modeled using partial correlations (two-tailed p<.05) controlling for age and 2-back accuracy. All participants were globally cognitively intact as indicated by Mini-Mental Status Exam and Dementia Rating Scale scores. Mean accuracy on the 2-back was 78±9% while reaction time averaged 1,027±192 ms. Mean CO and EF values showed a large range (CO: 3.55 to 6.31; EF: 0.36 to 0.76) but average values were within the normal range. After controlling for age and 2-back accuracy, lower EF was related to decrease in left insula activity (r=0.61, p=0.03). There were trends for EF to be related to accuracy (r=0.47, p=0.09) and reaction time (r=?0.48, p=0.09). CO was also related to insula activity (r=0.60, p=0.04) and activity in the supplementary motor area activity (r=0.66, p=0.01). Cardiac performance was related to decreased efficiency in task related brain areas and tended to be related to performance on a VWM task in elderly patients with CVD. Results have implications for a line of investigation indicating that cardiac and systemic vascular indices could be used as proxy measures to examine mechanisms of cerebrovascular dysfunction in the elderly.

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

2011-01-01

156

Optimized Temporary Biventricular Pacing Acutely Improves Intraoperative Cardiac Output After Weaning From Cardiopulmonary Bypass - A Sub-study of a Randomized Clinical Trial  

PubMed Central

Objective Permanent biventricular pacing benefits patients with heart failure and interventricular conduction delay, but the importance of pacing with and without optimization in patients at risk of low cardiac output after heart surgery is unknown. We hypothesized that pacing parameters independently affect cardiac output. Accordingly, we analyzed aortic flow measured with an electromagnetic flowmeter in patients at risk of low cardiac output, during an ongoing randomized clinical trial of biventricular pacing (n=11) vs. standard of care (n=9). Methods A sub-study was conducted in all 20 patients, in both groups, with stable pacing after coronary artery bypass grafting and/or valve surgery. Ejection fraction averaged 33±15%, QRS duration 116±19 msec. Effects were measured within one hour of the conclusion of cardiopulmonary bypass. Atrioventricular delay (7 settings) and interventricular delay (9 settings) were optimized in random sequence. Results Optimization of atrioventricular delay (171±8 msec), at an interventricular delay of 0 msec, increased flow 14% vs. the worst setting (111±11 msec, p < 0.001) and 7% vs. nominal atrioventricular delay (120 msec, p < 0.001). Interventricular delay optimization increased flow 10% vs. the worst setting (p < 0.001) and 5% vs. nominal interventricular delay (0 msec, p < 0.001). Optimized pacing increased cardiac output 13% vs. atrial pacing at matched heart rate (5.5±0.5 vs. 4.9±0.6 L/min; p = 0.003) and 10% vs. sinus rhythm (5.0±0.6 L/min; p = 0.019). Conclusions Temporary biventricular pacing increases intraoperative cardiac output in patients with left ventricular dysfunction undergoing cardiac surgery. Atrioventricular and interventricular delay optimization maximizes this benefit.

Wang, Daniel Y.; Richmond, Marc E.; Quinn, T. Alexander; Mirani, Ajay J.; Rusanov, Alexander; Yalamanchi, Vinay; Weinberg, Alan D.; Cabreriza, Santos E.; Spotnitz, Henry M.

2010-01-01

157

ECG patch monitors for assessment of cardiac rhythm abnormalities.  

PubMed

The primary goal of long-term monitoring is the improvement of diagnostic yield. Despite the clear utility of Holter monitoring in clinical cardiology, issues of relatively low diagnostic yield, cost and inconvenience have motivated the development of ultra-portable devices referred to as ECG patch monitors. Although the "gold standard" for assessing cardiac rhythm abnormalities remains a 12-lead Holter, there is an increasing interest in portable monitoring devices that provide the opportunity for evaluating cardiac rhythm in real-world environments such as the workplace or home. To facilitate patient acceptance these monitors underwent a radical miniaturization and redesign to include wireless communication, water proofing and a patch carrier for attaching devices directly to the skin. We review recent developments in the field of "patch" devices primarily designed for very long-term monitoring of cardiac arrhythmic events. As the body of supporting clinical validation data grows, these devices hold promise for a variety of cardiac monitoring applications. From a clinical and research standpoint, the capacity to obtain longitudinal cardiac activity data by patch devices may have significant implications for device selection, monitoring duration, and care pathways for arrhythmia evaluation and atrial fibrillation surveillance. From a research standpoint, the new devices may allow for the development of novel diagnostic algorithms with the goal of finding patterns and correlations with exercise and drug regimens. PMID:24215754

Lobodzinski, S Suave

2013-01-01

158

Outcomes Assessment: Not Synonymous with Inputs and Outputs.  

ERIC Educational Resources Information Center

Presents a rationale for the use of outcomes assessment and identifies three competing assessment perspectives that examine quality: looking at users from the perspective of the academic library; looking at libraries from the users' perspectives; and libraries in the life of the institution. Discusses information literacy, and differentiating…

Dugan, Robert E.; Hernon, Peter

2002-01-01

159

Measurement of cardiac output before and after cardiopulmonary bypass: Comparison among aortic transit-time ultrasound, thermodilution, and noninvasive partial CO 2 rebreathing  

Microsoft Academic Search

Objectives: A noninvasive continuous cardiac output system (NICO) has been developed recently. NICO uses a ratio of the change in the end-tidal carbon dioxide partial pressure and carbon dioxide elimination in response to a brief period of partial rebreathing to measure CO. The aim of this study was to compare the agreement among NICO, bolus (TDCO), and continuous thermodilution (CCO),

Monica Botero; David Kirby; Emilio B. Lobato; Edward D. Staples; Nikolaus Gravenstein

2004-01-01

160

Beat-by-beat analysis of cardiac output and blood pressure responses to short-term barostimulation in different body positions  

NASA Astrophysics Data System (ADS)

Rapid quantification of the human baro-reflex control of heart rate has been achieved on a beat-by-beat basis using a neck-chamber with quick ECG-triggered pressure changes. Referring to recent findings on heart rate and stroke volume, the present study uses this technique to compare cardiac output as well as blood pressure changes in supine and upright position to investigate feedback effects and to confirm postural reflex modifications not revealed by RR-interval changes. A suction profile starting at +40 mmHg and running 7 steps of pressure decrease down to -65 mmHg was examined in 0° and 90° tilting position while beat-by-beat recordings were done of heart rate, stroke volume (impedance-cardiography) and blood pressure (Finapres tm) (n=16). The percentual heart rate decrease failed to be significantly different between positions. A suction-induced stroke volume increase led to a cardiac output almost maintained when supine and significantly increased when upright. A decrease in all blood pressure values was found during suction, except for systolic values in upright position which increased. Conclusively, (a) it is confirmed that different inotropy accounts for the seen gravitational effect on the cardiac output not represented by heart rate; (b) identical suction levels in different positions lead to different stimuli at the carotid receptor. This interference has to be considered in microgravity studies by beat-by-beat measurement of cardiac output and blood pressure.

Hildebrandt, Wulf; Schütze, Harald; Stegemann, J.

161

No difference in the hemodynamic response to Nordic pole walking vs. conventional brisk walking — A randomized exercise field test using the ultrasonic cardiac output monitor (USCOM)  

Microsoft Academic Search

IntroductionNordic pole walking (NW) has gained significant attention to increase caloric expenditure vs. conventional walking without poles. However data are pending regarding the hemodynamic response of Nordic pole walking vs. walking. We hypothesized that NW increases cardiac output stronger than conventional walking at a given perceived level of physical exertion in a field test.

Karsten Knobloch

2009-01-01

162

Mitral Doppler Indices Are Superior to Two-Dimensional Echocardiographic and Hemodynamic Variables in Predicting Responsiveness of Cardiac Output to a Rapid Intravenous Infusion of Colloid  

Microsoft Academic Search

We hypothesized that mitral flow (MF) Doppler meas- urements could be used to predict cardiac output (CO) responsiveness to fluid challenge. Fourteen patients with normal systolic and diastolic function, scheduled for coronary artery bypass graft surgery, were evalu- ated as part of a pilot study in which preload was varied immediately before the beginning of cardiopulmonary bypass. A Validation group

Robert Lattik; Pierre Couture; Michel Carrier; Jean Taillefer; Jean-Claude Tardif

2002-01-01

163

An Evaluation of a Noninvasive Cardiac Output Measurement Using Partial Carbon Dioxide Rebreathing in Children  

Microsoft Academic Search

Cardiacoutput(CO)isanimportanthemodynamicmeas- urethathelpstoguidethetherapyofcriticallyillpatients. Invasive CO assessment in infants and children is often avoided because of the inherent risks. A noninvasive CO monitor that uses partial rebreathing has been recently developed to determine CO via the Fick principle for car- bon dioxide. There have been no clinical studies confirm- ing its accuracy in pediatric patients. This is a prospective observational study of

Richard J. Levy; Rosetta M. Chiavacci; Susan C. Nicolson; Jonathan J. Rome; Richard J. Lin; Mark A. Helfaer; Vinay M. Nadkarni

2004-01-01

164

Uncalibrated pulse power analysis fails to reliably measure cardiac output in patients undergoing coronary artery bypass surgery  

PubMed Central

Introduction Uncalibrated arterial pulse power analysis has been recently introduced for continuous monitoring of cardiac index (CI). The aim of the present study was to compare the accuracy of arterial pulse power analysis with intermittent transpulmonary thermodilution (TPTD) before and after cardiopulmonary bypass (CPB). Methods Forty-two patients scheduled for elective coronary surgery were studied after induction of anaesthesia, before and after CPB respectively. Each patient was monitored with the pulse contour cardiac output (PiCCO) system, a central venous line and the recently introduced LiDCO monitoring system. Haemodynamic variables included measurement of CI derived by transpulmonary thermodilution (CITPTD) or CI derived by pulse power analysis (CIPP), before and after calibration (CIPPnon-cal., CIPPcal.). Percentage changes of CI (?CITPTD, ?CIPPnon-cal./PPcal.) were calculated to analyse directional changes. Results Before CPB there was no significant correlation between CIPPnon-cal. and CITPTD (r2 = 0.04, P = 0.08) with a percentage error (PE) of 86%. Higher mean arterial pressure (MAP) values were significantly correlated with higher CIPPnon-cal. (r2 = 0.26, P < 0.0001). After CPB, CIPPcal. revealed a significant correlation compared with CITPTD (r2 = 0.77, P < 0.0001) with PE of 28%. Changes in CIPPcal. (?CIPPcal.) showed a correlation with changes in CITPTD (?CITPTD) only after CPB (r2 = 0.52, P = 0.005). Conclusions Uncalibrated pulse power analysis was significantly influenced by MAP and was not able to reliably measure CI compared with TPTD. Calibration improved accuracy, but pulse power analysis was still not consistently interchangeable with TPTD. Only calibrated pulse power analysis was able to reliably track haemodynamic changes and trends.

2011-01-01

165

Intraoperative cardiac assessment with transesophageal echocardiography for decision-making in cardiac anesthesia.  

PubMed

Transesophageal echocardiography is an invaluable hemodynamic monitoring modality. Extended and anatomically based evaluation of cardiac function with transesophageal echocardiography is essential to prompt and accurate decision-making in anesthetic management during cardiac surgery. Fractional shortening and fractional area changes are indices widely used to assess the global systolic performance of the left ventricle. Monitoring regional function using semi-quantitative scoring has been demonstrated to be a more sensitive indicator of myocardial ischemia. Assessment of left ventricular diastolic function should be performed in a systematic way, measuring transmitral flow, pulmonary venous flow, transmitral color M-mode flow propagation velocity, and mitral annulus tissue Doppler imaging. The unique anatomical features of the right ventricle make echocardiographic evaluation complicated and therefore less frequently employed. Right ventricular fractional area change, tricuspid annular plane systolic excursion, maximal systolic tricuspid annular velocity with tissue Doppler imaging, and myocardial performance index are indices successfully incorporated into intraoperative right ventricular assessment. Left ventricular outflow tract obstruction with systolic anterior motion of the mitral valve may develop after cardiac procedures. Transesophageal echocardiography plays a central role in prevention as well as diagnosis of systolic anterior motion. Transesophageal echocardiography is extremely useful not only for detecting and locating intracardiac air, but also for guiding and evaluating the procedures to remove air. Air is likely to persist in the right and left superior pulmonary vein, left ventricular apex, left atrium, right coronary sinus of Valsalva, and ascending aorta. Accurate evaluation of cardiac function depends on performing TEE examination properly and obtaining optimal images. PMID:23404310

Akiyama, Koichi; Arisawa, Shoji; Ide, Masahiro; Iwaya, Masaaki; Naito, Yoshiyuki

2013-06-01

166

Mixed venous blood gases are superior to arterial blood gases in assessing acid-base status and oxygenation during acute cardiac tamponade in dogs.  

PubMed Central

Recent reports using anesthetized ventilator-dependent animal models, have suggested that in certain shock states, a disparity exists between arterial and mixed venous blood gases with regard to acid-base status and oxygenation. In a chronically instrumented unanesthetized canine model of acute cardiac tamponade breathing room air, we studied the effect of a graded decline in cardiac output on arterial and mixed venous pH, PCO2, and PO2. Cardiac tamponade resulted in a profound arterial respiratory alkalosis, whereas mixed venous pH, PCO2, and calculated serum bicarbonate levels remained relatively unchanged. As intrapericardial pressure increased and cardiac output declined, the difference between arterial and mixed venous PCO2 progressively increased. Further, whereas arterial oxygenation improved as cardiac output declined, mixed venous oxygenation steadily worsened. This disparity began early in cardiac tamponade (reductions in cardiac output of 20-40%) long before arterial blood pressure began to fall and progressively worsened as hemodynamic deterioration and lactic acidosis developed. Our findings are consistent with the hypothesis that a reduction in blood flow, resulting in decreased CO2 delivery to the lungs, is the primary mechanism responsible for the difference in pH and PCO2 observed between arterial and mixed venous blood. In this conscious, spontaneously breathing animal model, mixed venous blood gases thus are superior to arterial blood gases in assessing acid-base status and oxygenation, even early in acute cardiac tamponade when the decline in cardiac output is in the range of 20 to 40% and arterial blood pressure has not changed significantly.

Mathias, D W; Clifford, P S; Klopfenstein, H S

1988-01-01

167

Micro-CT imaging assessment of dobutamine-induced cardiac stress in rats  

PubMed Central

Introduction Dobutamine (DOB) stress in animal models of heart disease has been imaged so far using echocardiography and magnetic resonance imaging. The purpose of this study was to assess normal response to DOB stress in rats using anatomical and functional data using microcomputed tomography (CT). Methods Ten normal adult male rats were first injected with a liposomal-based blood pool contrast agent and next infused with DOB via a tail vein catheter. Using prospective gating, 5 pairs of systole/diastole micro-CT images were acquired (a) pre-infusion baseline; (b) at heart rate plateau during infusion of 10 µg/kg/min DOB; (c) at post-DOB infusion baseline; (d) at heart rate plateau during infusion of 30 µg/kg/min DOB; and (e) after post-infusion return to baseline. Heart rate, peripheral and breathing distensions were monitored by oximetry. Micro-CT images with 88-micron isotropic voxels were segmented to obtain cardiac function based on volumetric measurements of the left ventricle. Results DOB stress increased heart rate and cardiac output with both doses. Ejection fraction increased above baseline by an average of 35.9% with the first DOB dose and 18.4% with the second dose. No change was observed in relative peripheral arterial pressures associated with the significant increases in cardiac output. Discussion Micro-CT proved to be a robust imaging method able to provide isotropic data on cardiac morphology and function. Micro-CT has the advantage of being faster and more cost- effective than MR and is able to provide higher accuracy than echocardiography. The impact of such an enabling technology can be enormous in evaluating cardiotoxic effects of various test drugs.

Badea, Cristian T.; Hedlund, Laurence W.; Cook, James; Berridge, Brian R.; Johnson, G. Allan

2010-01-01

168

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

169

Role of cardiac output versus peripheral vasoconstriction in mediating muscle metaboreflex pressor responses: dynamic exercise versus postexercise muscle ischemia  

PubMed Central

Muscle metaboreflex activation (MMA) during submaximal dynamic exercise in normal individuals increases mean arterial pressure (MAP) via increases in cardiac output (CO) with little peripheral vasoconstriction. The rise in CO occurs primarily via increases in heart rate (HR) with maintained or slightly increased stroke volume. When the reflex is sustained during recovery (postexercise muscle ischemia, PEMI), HR declines yet MAP remains elevated. The role of CO in mediating the pressor response during PEMI is controversial. In seven chronically instrumented canines, steady-state values with MMA during mild exercise (3.2 km/h) were observed by reducing hindlimb blood flow by ?60% for 3–5 min. MMA during exercise was followed by 60 s of PEMI. Control experiments consisted of normal exercise and recovery. MMA during exercise increased MAP, HR, and CO by 55.3 ± 4.9 mmHg, 42.5 ± 6.9 beats/min, and 2.5 ± 0.4 l/min, respectively. During sustained MMA via PEMI, MAP remained elevated and CO remained well above the normal recovery levels. Neither MMA during dynamic exercise nor during PEMI significantly affected peripheral vascular conductance. We conclude that the sustained increase in MAP during PEMI is driven by a sustained increase in CO not peripheral vasoconstriction.

Spranger, Marty D.; Sala-Mercado, Javier A.; Coutsos, Matthew; Kaur, Jasdeep; Stayer, Doug; Augustyniak, Robert A.

2013-01-01

170

Exercise-related change in airway blood flow in humans: Relationship to changes in cardiac output and ventilation  

PubMed Central

This study examined the relationship between airway blood flow (Q?aw), ventilation (V?E) and cardiac output (Q?tot) during exercise in healthy humans (n = 12, mean age 34 ± 11 yr). Q?aw was estimated from the uptake of the soluble gas dimethyl ether while V?E and Q?tot were measured using open circuit spirometry. Measurements were made prior to and during exercise at 34 ± 5W (Load 1) and 68 ± 10 W (Load 2) and following the cessation of exercise (recovery). Q?aw increased in a stepwise fashion (P < 0.05) from rest (52.8 ± 19.5 µl min?1 ml?1) to exercise at Load 1 (67.0 ± 20.3 µl min?1 ml?1) and Load 2 (84.0 ± 22.9 µl min?1 ml?1) before returning to pre-exercise levels in recovery (51.7 ± 13.2 µl min?1 ml?1). Q?aw was positively correlated with both Q?tot (r = 0.58, P < 0.01) and V?E (r = 0.50, P < 0.01). These results demonstrate that the increase in Q?aw is linked to an exercise related increase in both Q?tot and V?E and may be necessary to prevent excessive airway cooling and drying.

Morris, Norman R.; Ceridon, Maile L.; Beck, Kenneth C.; Strom, Nicholas A.; Schneider, Donald A.; Mendes, Eliana S.; Wanner, Adam; Johnson, Bruce D.

2009-01-01

171

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.

Grollmuss, Oswin; Gonzalez, Patricia

2014-01-01

172

Diesel Exhaust Inhalation Increases Cardiac Output, Bradyarrhythmias, and Parasympathetic Tone in Aged Heart Failure-Prone Rats  

EPA Science Inventory

Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance...

173

Clinical validation of a real-time data processing system for cardiac output and arterial pressure measurement during intraoperative biventricular pacing optimization.  

PubMed

Biventricular pacing (BiVP) improves cardiac output (CO) and mean arterial pressure (MAP) after cardiopulmonary bypass (CPB) in selected patients at risk for acute left heart failure after cardiac surgery. Optimization of atrioventricular delay (AVD) and interventricular delay (VVD) to maximize the hemodynamic effect of pacing requires rapid and accurate data processing. Conventional post hoc data processing (PP) is accurate but time-consuming, and infeasible in the intraoperative setting. We created a customized, real-time data processing (RTP) system to improve data processing efficiency, while maintaining accuracy. Biventricular pacing optimization was performed within 1 hour of the conclusion of CPB in 10 patients enrolled in the Biventricular Pacing After Cardiac Surgery trial. Cardiac output, measured by an electromagnetic flow meter, and arterial pressure were recorded as AVD was randomly varied across seven settings and VVD across nine settings. Post hoc data processing values calculated by two observers were compared to RTP-generated outputs for CO and MAP. Interexaminer reliability coefficients were generated to access the dependability of RTP. Interexaminer reliability coefficient values ranged from 0.997 to 0.999, indicating RTP is as reliable as PP for optimization. Real-time data processing is instantaneous and therefore is more practical in a clinical setting than the PP method. Real-time data processing is useful for guiding intraoperative BiVP optimization and merits further development. PMID:22395120

Johnson, Christopher K; Cabreriza, Santos E; Sahar, Rana L; Rusanov, Alexander; Wang, Daniel Y; Cheng, Bin; Gendy, Mira S; Quinn, T Alexander; Spotnitz, Henry Michael

2012-01-01

174

Prospective Assessment After Pediatric Cardiac Ablation  

PubMed Central

A multicenter prospective study was designed and implemented as an activity of the Pediatric Electrophysiology Society to assess the risks associated with radiofrequency ablation in children. Patients (age 0–15 years) with supraventricular tachycardia due to accessory path-ways or atrioventricular nodal reentry were enrolled and studied prior to ablation and periodically by clinical evaluation, electrocardiogram (ECG), Holter monitor, and echocardiogram. In addition, a national registry was established, to which the contributing centers report all pediatric patients undergoing ablation at their center. Initial electrophysiological study tracings and all noninvasive studies undergo blinded outside review for quality control. Clinical endpoints were death, recurrence, proarrhythmia, and echocardiographic abnormality. A pilot study demonstrated excellent agreement concerning diagnoses of previously reported ablation patients between the reporting center and the blinded reviewer (kappa = 0.938 ± 0.062). A total of 317 patients were enrolled in the ongoing study from April 1, 1999 to December 31, 2000. The success rate of ablations was 96% with a complication rate of 4.3% for electrophysiological study and 2.9% for the ablation procedure. Comparison of the registry group versus the study group shows that the groups are comparable in terms of patient characteristics, diagnoses, and the results of ablation making it less likely that the sample of prospectively enrolled patients is biased.

Van Hare, George F.; Carmelli, Dorit; Smith, W. Mcfate; Kugler, John; Silka, Michael; Friedman, Richard; Atkins, Dianne; Saul, J. Philip; Schaffer, Michael; Byrum, Craig; Dunnigan, Ann; Colan, Steven; Serwer, Gerald

2007-01-01

175

Lung diffusion capacity, oxygen uptake, cardiac output and oxygen transport during exercise before and after an himalayan expedition.  

PubMed

Studies were made of pulmonary diffusion capacity and oxygen transport before and after an expedition to altitudes at and above 4900 m. Maximum power (Pmax) and maximal oxygen uptake (VO2max) were measured in 11 mountaineers in an incremental cycle ergometer test (25W.min-1) before and after return from basecamp (30 days at 4900 m or higher). In a second test, cardiac output (Qc) and lung diffusion capacity of carbon monoxide (DL,cg) were measured by acetylene and CO rebreathing at rest and during exercise at low, medium and submaximal intensities. After acclimatization, VO2max and Pmax decreased by 5.1% [from 61.0 (SD 6.2) to 57.9 (SD 10.2) ml.kg-1, n.s.] and 9.9% [from 5.13 (SD 0.66) to 4.62 (SD 0.42) W.kg-1, n.s.], respectively. The maximal cardiac index and DL,cg decreased significantly by 15.6% [14.1 (SD 1.41) 1.min-1.m-2 to 11.9 (SD 1.44)1.min-1.m-2, P < 0.05] and 14.3% [85.9 (SD 4.36) ml.mmHg-1. min-1 to 73.6 (SD 15.2) ml.mmHg-1.min-1, P < 0.05], respectively. The expedition to high altitude led to a decrease in maximal Qc, oxygen uptake and DL,cg. A decrease in muscle mass and capillarity may have been responsible for the decrease in maximal Qc which may have resulted in a decrease of DL,cg and an increase in alveolar-arterial oxygen difference. The decrease in DL,cg especially at lower exercise intensities after the expedition may have been due to a ventilation-perfusion mismatch and changes in blood capacitance. At higher exercise intensities diffusion limitation due to reduced pulmonary capillary contact time may also have occurred. PMID:8891518

Steinacker, J M; Liu, Y; Böning, D; Halder, A; Maassen, N; Thomas, A; Stauch, M

1996-01-01

176

Use of a capillary input function with cardiac output for the estimation of lesion pharmacokinetic parameters: preliminary results on a breast cancer patient  

NASA Astrophysics Data System (ADS)

The objective of this work was to propose and demonstrate a novel technique for the assessment of tumour pharmacokinetic parameters together with a regionally estimated vascular input function. A breast cancer patient T2*-weighted dynamic contrast enhanced MRI (DCE-MRI) dataset acquired at high temporal resolution during the first-pass bolus perfusion was used for testing the technique. Extraction of the lesion volume transfer constant Ktrans together with the intravascular plasma volume fraction vp was achieved by optimizing a capillary input function with a measure of cardiac output using the principle of intravascular indicator dilution theory. For a region of interest drawn within the breast lesion a vp of 0.16 and a Ktrans of 0.70 min-1 were estimated. Despite the value of vp being higher than expected, estimated Ktrans was in accordance with the literature values. In conclusion, the technique proposed here, has the main advantage of allowing the estimation of breast tumour pharmacokinetic parameters from first-pass perfusion T2*-weighted DCE-MRI data without the need of measuring an arterial input function. The technique may also have applicability to T1-weighted DCE-MRI data.

Di Giovanni, P.; Ahearn, T. S.; Semple, S. I.; Azlan, C. A.; Lloyd, W. K. C.; Gilbert, F. J.; Redpath, T. W.

2011-03-01

177

Cardiac Rehabilitation Programs. Number 3. Health Technology Assessment Reports, 1991.  

National Technical Information Service (NTIS)

Cardiac rehabilitation is a continuing process whereby patients with cardiac disease are encouraged to achieve their maximal functional capacity and attain acceptable psychological, social, emotional, vocational, and economic status. Cardiac rehabilitatio...

S. S. Hotta

1991-01-01

178

Cardiac-respiratory self-gated cine ultra-short echo time (UTE) cardiovascular magnetic resonance for assessment of functional cardiac parameters at high magnetic fields  

PubMed Central

Background To overcome flow and electrocardiogram-trigger artifacts in cardiovascular magnetic resonance (CMR), we have implemented a cardiac and respiratory self-gated cine ultra-short echo time (UTE) sequence. We have assessed its performance in healthy mice by comparing the results with those obtained with a self-gated cine fast low angle shot (FLASH) sequence and with echocardiography. Methods 2D self-gated cine UTE (TE/TR?=?314 ?s/6.2 ms, resolution: 129?×?129 ?m, scan time per slice: 5 min 5 sec) and self-gated cine FLASH (TE/TR?=?3 ms/6.2 ms, resolution: 129?×?129 ?m, scan time per slice: 4 min 49 sec) images were acquired at 9.4 T. Volume of the left and right ventricular (LV, RV) myocardium as well as the end-diastolic and -systolic volume was segmented manually in MR images and myocardial mass, stroke volume (SV), ejection fraction (EF) and cardiac output (CO) were determined. Statistical differences were analyzed by using Student t test and Bland-Altman analyses. Results Self-gated cine UTE provided high quality images with high contrast-to-noise ratio (CNR) also for the RV myocardium (CNRblood-myocardium?=?25.5?±?7.8). Compared to cine FLASH, susceptibility, motion, and flow artifacts were considerably reduced due to the short TE of 314 ?s. The aortic valve was clearly discernible over the entire cardiac cycle. Myocardial mass, SV, EF and CO determined by self-gated UTE were identical to the values measured with self-gated FLASH and showed good agreement to the results obtained by echocardiography. Conclusions Self-gated UTE allows for robust measurement of cardiac parameters of diagnostic interest. Image quality is superior to self-gated FLASH, rendering the method a powerful alternative for the assessment of cardiac function at high magnetic fields.

2013-01-01

179

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.

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

2004-01-01

180

Pharmacokinetics, hemodynamic and metabolic effects of epinephrine to prevent post-operative low cardiac output syndrome in children  

PubMed Central

Introduction The response to exogenous epinephrine (Ep) is difficult to predict given the multitude of factors involved such as broad pharmacokinetic and pharmacodynamic between-subject variabilities, which may be more pronounced in children. We investigated the pharmacokinetics and pharmacodynamics of Ep, co-administered with milrinone, in children who underwent open heart surgical repair for congenital defects following cardiopulmonary bypass, including associated variability factors. Methods Thirty-nine children with a high risk of low cardiac output syndrome were prospectively enrolled. Ep pharmacokinetics, hemodynamic and metabolic effects were analyzed using the non-linear mixed effects modeling software MONOLIX. According to the final model, an Ep dosing simulation was suggested. Results Ep dosing infusions ranged from 0.01 to 0.23 ?g.kg-1.min-1 in children whose weight ranged from 2.5 to 58 kg. A one-compartment open model with linear elimination adequately described the Ep concentration-time courses. Bodyweight (BW) was the main covariate influencing clearance (CL) and endogenous Ep production rate (q0) via an allometric relationship: CL(BWi)?=??CL x (BWi)3/4 and q0(BWi)?=??q0 x (BWi )3/4. The increase in heart rate (HR) and mean arterial pressure (MAP) as a function of Ep concentration were well described using an Emax model. The effect of age was significant on HR and MAP basal level parameters. Assuming that Ep stimulated the production rate of plasma glucose, the increases in plasma glucose and lactate levels were well described by turnover models without any significant effect of age, BW or exogenous glucose supply. Conclusions According to this population analysis, the developmental effects of BW and age explained a part of the pharmacokinetic and pharmacodynamics between-subject variabilities of Ep administration in critically ill children. This approach ultimately leads to a valuable Ep dosing simulation which should help clinicians to determine an appropriate a priori dosing regimen.

2014-01-01

181

System and method for measuring cardiac output via thermal dilution using an implantable medical device with an external ultrasound power delivery system  

US Patent & Trademark Office Database

The implantable device is capable of performing thermal dilution analysis of the cardiac output of a patient using power delivered from an external source. By using power from an external source, the implantable device conserves its power resources for other purposes, such as for pacing or defibrillation therapy. In one example, an external programmer or bedside monitor provides power through a hand-held power delivery wand via electromagnetic induction, with the power routed from a subcutaneous coil to a heating element implanted in the right atrium, which heats blood as it passes through the right atrium. In another example, the heating element is formed of a material that generates heat in response to a beam of ultrasound provided by the wand. In either case, a downstream blood temperature profile is detected using a thermistor implanted in the pulmonary artery and cardiac output is then estimated by analyzing the temperature profile.

2009-12-15

182

An On-line Data Acquisition And Analysis System To Determine Cardiac Output: A One-step C02 Rebreathing Technique  

Microsoft Academic Search

This paper presents a computer-based automated data acquisition and analysis system to help determine cardiac output using a one-step CO, rebreathing technique. The one-step technique generates all the data required to solve the Fick equation for CQ by continuously monitoring expired CQ concentrations at the mouth during a 20-25 second rebreathing maneuver. Through use of digital signal processing techniques, the

D. F. Sittig; J. A. Pawelczyk

1991-01-01

183

Differences of cardiac output measurements by open-circuit acetylene uptake in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: a cohort study  

PubMed Central

Background As differences in gas exchange between pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) have been demonstrated, we asked if cardiac output measurements determined by acetylene (C2H2) uptake significantly differed in these diseases when compared to the thermodilution technique. Method Single-breath open-circuit C2H2 uptake, thermodilution, and cardiopulmonary exercise testing were performed in 72 PAH and 32 CTEPH patients. Results In PAH patients the results for cardiac output obtained by the two methods showed an acceptable agreement with a mean difference of -0.16 L/min (95% CI -2.64 to 2.32 L/min). In contrast, the agreement was poorer in the CTEPH group with the difference being -0.56 L/min (95% CI -4.96 to 3.84 L/min). Functional dead space ventilation (44.5 ± 1.6 vs. 32.2 ± 1.4%, p < 0.001) and the mean arterial to end-tidal CO2 gradient (9.9 ± 0.8 vs. 4.1 ± 0.5 mmHg, p < 0.001) were significantly elevated among CTEPH patients. Conclusion Cardiac output evaluation by the C2H2 technique should be interpreted with caution in CTEPH, as ventilation to perfusion mismatching might be more relevant than in PAH.

2012-01-01

184

NONINVASIVE CARDIAC OUTPUT MONITORING DURING EXERCISE TESTING: NEXFIN PULSE CONTOUR ANALYSIS COMPARED TO AN INERT GAS REBREATHING METHOD AND RESPIRED GAS ANALYSIS  

Microsoft Academic Search

Purpose. Exercise testing is often used to assess cardiac function during physical exertion to obtain diagnostic information. However, this procedure is limited to measuring the electrical activity of the heart using electrocardiography and intermittent blood pressure (BP) measurements and does not involve the continuous assessment of heart functioning. In this study, we compared continuous beat-to-beat pulse contour analysis to monitor

S. A. Bartels; W. J. Stok; R. Bezemer; R. J. Boksem; J Goudoever; T. G. V. Cherpanath; Lieshout van J. J; B. E. Westerhof; J. M. Karemaker; C. Ince

2011-01-01

185

The cardiac magnetic resonance (CMR) approach to assessing myocardial viability.  

PubMed

Cardiac magnetic resonance (CMR) is a noninvasive imaging method that can determine myocardial anatomy, function, perfusion, and viability in a relative short examination. In terms of viability assessment, CMR can determine viability in a non-contrast enhanced scan using dobutamine stress following protocols comparable to those developed for dobutamine echocardiography. CMR can also determine viability with late gadolinium enhancement (LGE) methods. The gadolinium-based contrast agents used for LGE differentiate viable myocardium from scar on the basis of differences in cell membrane integrity for acute myocardial infarction. In chronic myocardial infarction, the scarred tissue enhances much more than normal myocardium due to increases in extracellular volume. LGE is well validated in pre-clinical and clinical studies that now span from almost a cellular level in animals to human validations in a large international multicenter clinical trial. Beyond infarct size or infarct detection, LGE is a strong predictor of mortality and adverse cardiac events. CMR can also image microvascular obstruction and intracardiac thrombus. When combined with a measure of area at risk like T2-weighted images, CMR can determine infarct size, area at risk, and thus estimate myocardial salvage 1-7 days after acute myocardial infarction. Thus, CMR is a well validated technique that can assess viability by gadolinium-free dobutamine stress testing or late gadolinium enhancement. PMID:21882082

Arai, Andrew E

2011-12-01

186

Economic Assessment on Smoothing PV System's Output by Adjusting MPPT Control  

NASA Astrophysics Data System (ADS)

We have proposed a method which can smooth a short-term change in PV system's output by suppressing a response of MPPT against a rapid insolation change. Because our proposed method does not convert insolation to electricity when insolation changes rapidly, it might increase energy conversion loss and decrease economy of a PV system. Comparative assessment on economics was made for two PV systems equipped with an output smoothing function, i.e. our proposed system adjusting MPPT and a battery system. By using the data on insolation for a year, we evaluated the energy conversion loss of PV system, which utilizes the proposed MPPT for smoothing the output. Then, taking into account the required capacity of battery, we compared the annual cost for smoothing PV system's output. The result suggests that the proposed method could be more economical relative to the smoothing method using a battery with future target cost.

Kato, Takeyoshi; Ina, Nobuhiko; Suzuoki, Yasuo

187

Quantitative automated assessment of myocardial perfusion at cardiac catheterization.  

PubMed

Perfusion assessed in the cardiac catheterization laboratory predicts outcomes after myocardial infarction. The aim of this study was to investigate a novel method of assessing perfusion using digital subtraction angiography to generate a time-density curve (TDC) of myocardial blush, incorporating epicardial and myocardial perfusion. Seven pigs underwent temporary occlusion of the left anterior descending coronary artery for 60 minutes. Angiography was performed in the same projections before, during, and after occlusion. Perfusion parameters were obtained from the TDC and compared with Thrombolysis In Myocardial Infarction (TIMI) frame count and myocardial perfusion grade. In addition, safety and feasibility were tested in 8 patients after primary percutaneous coronary intervention. The contrast density differential between the proximal artery and the myocardium derived from the TDC correlated well with TIMI myocardial perfusion grade (R = 0.54, p <0.001). The arterial transit time derived from the TDC correlated with TIMI frame count (R = 0.435, p = 0.011). Using a cutoff of 2.4, the density/time ratio, a ratio of density differential to transit time, had sensitivity and specificity of 100% for coronary arterial occlusion. The positive and negative predictive values were 100%. The generation of a TDC was safe and feasible in 7 patients after acute myocardial infarctions, but the correlation between TDC-derived parameters and TIMI parameters did not reach statistical significance. In conclusion, this novel method of digital subtraction angiography with rapid, automated, quantitative assessment of myocardial perfusion in the cardiac catheterization laboratory correlates well with established angiographic measures of perfusion. Further studies to assess the prognostic value of this technique are warranted. PMID:18929697

Boyle, Andrew J; Schuleri, Karl H; Lienard, Jean; Vaillant, Regis; Chan, Michael Y; Zimmet, Jeffrey M; Mazhari, Ramesh; Centola, Marco; Feigenbaum, Gary; Dib, Joud; Kapur, Navin K; Hare, Joshua M; Resar, Jon R

2008-10-15

188

STATISTICAL AND DYNAMICAL DOWNSCALING OF GLOBAL MODEL OUTPUT FOR U.S. NATIONAL ASSESSMENT HYDROLOGICAL ANALYSES  

Microsoft Academic Search

1. NTRODUCTION Analyses performed for the US National Assessment require accurate projections of climate at scales below those resolved by global General Circulation Models (GCMs). Two techniques have been developed that counter this deficiency: semi- empirical (statistical) downscaling (SDS) of GCM outputs, and regional climate models (RCMs) nested within a GCM. To date, few studies have compared SDS and RCM

W. J. Gutowski; R. Wilby; L. E. Hay; C. J. Anderson; R. W. Arritt; M. P. Clark; G. H. Leavesley; Z. Pan; R. Silva; E. S. Takle

189

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 €.

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

2013-01-01

190

Health Technology Assessment Reports, 1987. Number 6. Cardiac Rehabilitation Services.  

National Technical Information Service (NTIS)

Cardiac rehabilitation services are comprehensive, long-term programs involving medical evaluation, prescribed exercise, cardiac risk factor modification, education, and counseling. The programs are designed to limit the physiologic and psychological effe...

E. Feigenbaum E. Carter

1988-01-01

191

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.

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

2004-01-01

192

A case of external iliac arteriovenous fistula and high-output cardiac failure after endovenous laser treatment of great saphenous vein.  

PubMed

Valvular incompetence in the great saphenous vein (GSV) is the most common cause of superficial venous insufficiency and symptomatic varicose vein development. Recently, less invasive modalities such as foam sclerotherapy, radiofrequency ablation (RFA), and endovenous laser treatment (EVLT) have gained popularity in the treatment of saphenofemoral junction and saphenous truncal incompetence over the traditional approach of surgical ligation and stripping. Here, we present the case of a 32-year-old woman who underwent EVLT and was diagnosed subsequently with ipsilateral external iliac arteriovenous (AV) fistula and high-output cardiac failure. She was stabilized medically and treated surgically with a covered stent placed in the external iliac artery with complete resolution of the fistula and cardiac failure. We reviewed the literature and discuss the complications of AV fistulae after EVLT. PMID:20100645

Ziporin, Scott J; Ifune, Catherine K; MacConmara, Malcolm P; Geraghty, Patrick J; Choi, Eric T

2010-03-01

193

Substrate stiffness-regulated matrix metalloproteinase output in myocardial cells and cardiac fibroblasts: Implications for myocardial fibrosis.  

PubMed

Cardiac fibrosis, an important pathological feature of structural remodeling, contributes to ventricular stiffness, diastolic dysfunction, arrhythmia and may even lead to sudden death. Matrix stiffness, one of the many mechanical factors acting on cells, is increasingly appreciated as an important mediator of myocardial cell behavior. Polydimethylsiloxane (PDMS) substrates were fabricated with different stiffnesses to mimic physiological and pathological heart tissues, and the way in which the elastic modulus of the substrate regulated matrix-degrading gelatinases in myocardial cells and cardiac fibroblasts was explored. Initially, an increase in cell spreading area was observed, concomitant with the increase in PDMS stiffness in both cells. Later, it was demonstrated that the MMP-2 gene expression and protein activity in myocardial cells and cardiac fibroblasts can be enhanced with an increase in PDMS substrate stiffness and, moreover, such gene- and protein-related increases had a significant linear correlation with the elastic modulus. In comparison, the MMP-9 gene and protein expressions were up-regulated in cardiac fibroblasts only, not in myocardial cells. These results implied that myocardial cells and cardiac fibroblasts in the myocardium could sense the stiffness in pathological fibrosis and showed a differential but positive response in the expression of matrix-degrading gelatinases when exposed to an increased stiffening of the matrix in the microenvironment. The phenomenon of cells sensing pathological matrix stiffness can help to increase understanding of the mechanism underlying myocardial fibrosis and may ultimately lead to planning cure strategies. PMID:24508540

Xie, Jing; Zhang, Quanyou; Zhu, Ting; Zhang, Yanyan; Liu, Bailin; Xu, Jianwen; Zhao, Hucheng

2014-06-01

194

Cardiac assessment of patients with late stage Duchenne muscular dystrophy  

PubMed Central

Background. Duchenne muscular dystrophy (DMD) patients used to die mainly from pulmonary problems. However, as advances in respiratory care increase life expectancy, mortality due to cardiomyopathy rises. Echocardiography remains the standard diagnostic modality for cardiomyopathy in DMD patients, but is hampered by scoliosis and poor echocardiographic acoustic windows in adult DMD patients. Multigated cardiac radionuclide ventriculography (MUGA) does not suffer from these limitations. N-terminal proBNP (NTproBNP) has shown to be a diagnostic factor for heart failure. We present our initial experience with plasma NT-proBNP measurement in the routine screening and diagnosis of cardiomyopathy in adult mechanically ventilated DMD patients. Methods. Retrospective study, 13 patients. Echocardiography classified left ventricular (LV) function as preserved or depressed. NT-proBNP was determined using immunoassay. LV ejection fraction (LVEF) was determined using MUGA. Results. Median (range) NT-proBNP was 73 (25 to 463) ng/l. Six patients had an NT-proBNP >125 ng/l. Seven patients showed an LVEF <45% on MUGA. DMD patients with depressed LV function (n=4) as assessed by echocardiography had significantly higher median NT-proBNP than those (n=9) with preserved LV function: 346 (266 to 463) ng/l versus 69 (25 to 257) ng/l (p=0.003). NT-proBNP significantly correlated with depressed LV function on echocardiogram and with LVEF determined by MUGA. Conclusion. Although image quality of MUGA is superior to echocardiography, the combination of echocardiography and NT-proBNP achieves similar results in the evaluation of left ventricular function and is less time consuming and burdensome for our patients. We advise to add NT-proBNP to echocardiography in the routine cardiac assessment of DMD patients. (Neth Heart J 2009;17:232-7.19789685) PMID:19789685

van Bockel, E.A.P.; Lind, J.S.; Zijlstra, J.G.; Wijkstra, P.J.; Meijer, P.M.; van den Berg, M.P.; Slart, R.H.J.A.; Aarts, L.P.H.J.; Tulleken, J.E.

2009-01-01

195

Cardiac biomarkers and risk assessment in patients undergoing major non-cardiac surgery: time to revise the guidelines?  

PubMed

Although the perioperative event rate has declined over the past 30 years, as a consequence of the developments in anesthesiology and surgical techniques, perioperative cardiovascular complications are still a significant clinical problem. At the end of the last century, a pooled analysis of several large studies found a 30-day incidence of cardiac events of 2.5% in unselected patients aged >40 years. The identification of myocardial injury after non-cardiac surgery is a problematic and tough challenge, since up to 50% of cardiac deaths actually occur in patients with no history of overt heart disease. Recently, among novel sensitive and specific cardiovascular risk markers, the European Society of Cardiology and European Society of Anesthesiology guidelines for preoperative cardiac risk assessment have recommended that preoperative brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) measurement should be considered in high-risk patients undergoing non-cardiac surgery. However, several recent studies and meta-analyses, published in the last 5 years, strongly support the use of both assays of cardiac B-type natriuretic peptides and troponins, for risk stratification in patients undergoing non-cardiac surgery, in order to improve operative and postoperative outcome. Indeed, an increase in specific cardiac biomarkers, as it is the case for natriuretic peptides and troponins, always indicates that the heart is under a stress condition or even actually injured, respectively. In conclusion, the authors suggest that future guidelines on cardiovascular risk evaluation in patients undergoing major surgical procedures should take into account the following evidence. PMID:24501160

Clerico, Aldo; Emdin, Michele; Passino, Claudio

2014-07-01

196

Assessment of cardiac iron by MRI susceptometry and R2* in patients with thalassemia  

Microsoft Academic Search

A magnetic resonance imaging cardiac magnetic susceptometry (MRI-CS) technique for assessing cardiac tissue iron concentration based on phase mapping was developed. Normal control subjects (n=9) and thalassemia patients (n=13) receiving long-term blood transfusion therapy underwent MRI-CS and MRI measurements of the cardiac relaxation rate R2*. Using MRI-CS, subepicardium and subendocardium iron concentrations were quantified exploiting the hemosiderin\\/ferritin iron specific magnetic

Zhiyue J. Wang; Roland Fischer; Zili Chu; Donald H. Mahoney Jr.; Brigitta U. Mueller; Raja Muthupillai; Ellen B. James; Rajesh Krishnamurthy; Taylor Chung; Eric Padua; Elliott Vichinsky; Paul Harmatz

2010-01-01

197

Computerized assessment and tracking of cardiac angiographic image quality  

NASA Astrophysics Data System (ADS)

With the rising prominence of filmless and quantitative imaging technologies in modern cardiac catheterization laboratories, new approaches to assessing angiographic image quality (AIQ) are required. This paper describes a system of radiographic phantom modules and associated digital image analysis software for assessing and tracking the inherent low contrast AIQ of a particular image chain as well as its suitability for quantitative coronary arteriography (QCA) analysis. The system uses two phantom modules in conjunction with a patient simulation apparatus. Computer software operates on digital radiographic images of the phantoms and extracts a number of parameters characterizing the imaging performance of the particular image chain. An arterial phantom module is used to evaluate angiographic imaging performance relating to QCA and an orthogonal array of small bronze ball bearings is used to derive AIQ parameters that complement standard manual measurements. In addition to passively monitoring AIQ, this new approach has the benefit of enabling active compensation for variability in AIQ and its effect on QCA results from one image chain to the next.

Lefree, Michelle T.; Krus, Daniel L.; Sitomer, Joseph

1998-07-01

198

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

199

Assessment of right ventricular function with 320-slice volume cardiac CT: comparison with cardiac magnetic resonance imaging.  

PubMed

To evaluate the accuracy and feasibility of right ventricular function parameters measurement using 320-slice volume cardiac CT. Retrospective analysis of 50 consecutive patients (23 men, 27 women) with suspected pulmonary diseases was performed in electrocardiogram (ECG)-gated cardiac CT and cardiac magnetic resonance (CMR). Parameters including right ventricular end-diastolic volume (RVEDV), right ventricular end- systolic volume (RVESV), right ventricular stroke volume (RVSV), right ventricular cardiac output (RVCO), and right ventricular ejection fraction (RVEF) were semi-automatically and separately calculated from both CT and CMR data. Significant difference between measurements was measured by paired t test and two-variable linear regression analysis with Pearson's correlation coefficient. Bland-Altman analysis was performed in each pair of parameters. There was little variability between the measurements by the two observers (kappa = 0.895-0.980, P < 0.05). There was good correlation between all parameters obtained by CT and CMR (P < 0.001): RVEDV (108.5 ± 21.9 ml, 113.5 ± 24.8 ml, r = 0.944), RVESV (69.8 ± 33.4 ml, 73.2 ± 35.4 ml, r = 0.972), RVSV (39.0 ± 13.2 ml, 40.2 ± 13.3 ml, r = 0.977), RVCO (2.6 ± 0.7 l, 2.6 ± 0.7 l. r = 0.958), RVEF (38.8 ± 19.1 %, 39.1 ± 19.3 %, r = 0.990), and there was no significant difference between CT and CMR measurements in RVEF (n = 50, t = -0.677, P > 0.05). 320-slice volume cardiac CT is an accurate non-invasive technique to evaluate RV function. PMID:23179750

Huang, Xiaoyong; Pu, Xin; Dou, Ruiyu; Guo, Xi; Yan, Zixu; Zhang, Zhaoqi; Li, Meng; Jiang, Hong; Lu, Biao

2012-12-01

200

Comparison of echocardiographic assessment of cardiac hemodynamics in the intensive care unit with right-sided cardiac catheterization.  

PubMed

Estimation of left ventricular filling pressure and cardiac index is important in the management of patients requiring right heart catheterization. Doppler echocardiography can provide a noninvasive measure of these parameters, but its accuracy in individual measurements, predicting hemodynamic subgroups, and in tracking serial changes in critically ill patients remains to be elucidated. Left ventricular filling pressure and cardiac index were assessed in 49 critically ill patients requiring right heart catheterization and Doppler echocardiographic studies. Two or more serial studies were performed in 18 of these subjects. Patients were placed into 1 of 4 hemodynamic subgroups for each technique based on the acquired hemodynamic parameters. Left ventricular filling pressure and cardiac index by Doppler echocardiography and right heart catheterization were similar (21 +/- 8 vs 20 +/- 8 mm Hg; 3.0 +/- 1.2 vs 2.9 +/- 1.2 L/min/m2, respectively) and correlated well with each other (left ventricular filling pressure, r = 0.88; cardiac index, r = 0.92). The Doppler technique accurately placed 73 of 76 studies into the correct hemodynamic subgroup. The noninvasive technique also reliably tracked serial hemodynamic measurements. We conclude that Doppler echocardiography accurately assesses left heart hemodynamics in critically ill patients. Since this technique can be readily acquired, it can be ideal for the rapid assessment of hemodynamic parameters in critically ill patients, especially when right heart catheterization is delayed or is problematic. PMID:7639166

Dabaghi, S F; Rokey, R; Rivera, J M; Saliba, W I; Majid, P A

1995-08-15

201

Assessment of Patient Knowledge of Cardiac Rehabilitation: Brazil vs Canada  

PubMed Central

Background Much of the relationship between health status and knowledge about health and disease can be attributed to the combined effects of disparate health-related behavior, environmental conditions, and socioeconomic structures as well as contact with and delivery of health care. Objective The aim of this study was to describe and compare knowledge of patients with coronary artery disease (CAD) enrolled in cardiac rehabilitation (CR) programs in Brazil and Canada about CAD-related factors. Methods Two samples of 300 Brazilian and 300 Canadian patients enrolled in CR were compared cross-sectionally. Brazilian patients were recruited from 2 CR centers in Southern Brazil, whereas Canadian patients were recruited from 1 CR center in Ontario. Knowledge was assessed using the Coronary Artery Disease Education Questionnaire (CADE-Q), psychometrically validated in Portuguese and English. The data were processed through descriptive statistics, post-hoc and the Student's t-tests. Results The mean total knowledge score for the whole sample was 41.42 ± 9.3. Canadian respondents had significantly greater mean total knowledge scores than Brazilian respondents. The most highly knowledgeably domain in both samples was physical exercise. In 13 of 19 questions, Canadian respondents reported significantly greater knowledge scores than Brazilian respondents. Conclusions Canadian outpatients reported significantly greater knowledge than their Brazilian counterparts. The results also suggest that having a structured educational curriculum in CR programs may contribute to increased patient knowledge, which may ultimately facilitate behavioral changes.

Ghisi, Gabriela Lima de Melo; Oh, Paul; Thomas, Scott; Benetti, Magnus

2013-01-01

202

[The influence of LAP and cardiac output on the pulmonary gas exchange. Intraoperative studies in cardio-surgical patients (author's transl)].  

PubMed

In 21 patients haemodynamic parameters and pulmonary gas exchange were investigated after open heart surgery with cardio-pulmonary bypass (aortic valve replacement, AVR (n = 8); mitral valve replacement, MVR (n = 6); aorto coronary bypass; ACB (n = 7). For describing gas exchange function of the lung the O2-CO2 diagram was used. Stepwise increase of left atrial pressure (LAP) was followed by increasing cardiac output (CO) only in the AVR and ACB groups, whereas in the MVR group CO did not increase. Rising venous admixture (Qs/Qt) under these circumstances was related to CO only in the AVR and ACB groups. In the MVR group Qs/Qt did not change. Qs/Qt is related to low VA/Q areas in the lung. Increased CO leads to rising Qs/Qt from these low VA/Q-areas. PMID:6787948

Voigt, E; van Deyk, K; Seybold-Epting, W

1981-05-01

203

A Case of Femoral Arteriovenous Fistula Causing High-Output Cardiac Failure, Originally Misdiagnosed as Chronic Fatigue Syndrome  

PubMed Central

Percutaneous arterial catheterisation is commonly undertaken for a range of diagnostic and interventional procedures. Iatrogenic femoral arteriovenous fistulas are an uncommon complication of these procedures. Most are asymptomatic and close spontaneously, but can rarely increase in size leading to the development of symptoms. We report a case of an iatrogenic femoral arteriovenous fistula, causing worsening congestive cardiac failure, in a 34-year-old marathon runner. This was originally diagnosed as chronic fatigue syndrome. Following clinical examination, duplex ultrasound, and CT angiography a significant arteriovenous fistula was confirmed. Elective open surgery was performed, leading to a dramatic and rapid improvement in symptoms. Femoral arteriovenous fistulas have the potential to cause significant haemodynamic effects and can present many years after the initial procedure. Conservative, endovascular, and open surgical management strategies are available.

Porter, J.; Al-Jarrah, Q.; Richardson, S.

2014-01-01

204

A case of femoral arteriovenous fistula causing high-output cardiac failure, originally misdiagnosed as chronic fatigue syndrome.  

PubMed

Percutaneous arterial catheterisation is commonly undertaken for a range of diagnostic and interventional procedures. Iatrogenic femoral arteriovenous fistulas are an uncommon complication of these procedures. Most are asymptomatic and close spontaneously, but can rarely increase in size leading to the development of symptoms. We report a case of an iatrogenic femoral arteriovenous fistula, causing worsening congestive cardiac failure, in a 34-year-old marathon runner. This was originally diagnosed as chronic fatigue syndrome. Following clinical examination, duplex ultrasound, and CT angiography a significant arteriovenous fistula was confirmed. Elective open surgery was performed, leading to a dramatic and rapid improvement in symptoms. Femoral arteriovenous fistulas have the potential to cause significant haemodynamic effects and can present many years after the initial procedure. Conservative, endovascular, and open surgical management strategies are available. PMID:24959370

Porter, J; Al-Jarrah, Q; Richardson, S

2014-01-01

205

Effect of increased cardiac output on liver blood flow, oxygen exchange and metabolic rate during longterm endotoxin-induced shock in pigs  

PubMed Central

We investigated hepatic blood flow, O2 exchange and metabolism in porcine endotoxic shock (Control, n=8; Endotoxin, n=10) with administration of hydroxyethylstarch to maintain arterial pressure (MAP)>60?mmHg. Before and 12, 18 and 24?h after starting continuous i.v. endotoxin we measured portal venous and hepatic arterial blood flow, intracapillary haemoglobin O2 saturation (Hb-O2%) of the liver surface and arterial, portal and hepatic venous lactate, pyruvate, glyercol and alanine concentrations. Glucose production rate was derived from the plasma isotope enrichment during infusion of [6,6-2H2]-glucose. Despite a sustained 50% increase in cardiac output endotoxin caused a progressive, significant fall in MAP. Liver blood flow significantly increased, but endotoxin affected neither hepatic O2 delivery and uptake nor mean intracapillary Hb-O2% and Hb-O2% frequency distributions. Endotoxin nearly doubled endogenous glucose production rate while hepatic lactate, alanine and glycerol uptake rates progressively decreased significantly. The lactate uptake rate even became negative (P<0.05 vs Control). Endotoxin caused portal and hepatic venous pH to fall significantly concomitant with significantly increased arterial, portal and hepatic venous lactate/pyruvate ratios. During endotoxic shock increased cardiac output achieved by colloid infusion maintained elevated liver blood flow and thereby macro- and microcirculatory O2 supply. Glucose production rate nearly doubled with complete dissociation of hepatic uptake of glucogenic precursors and glucose release. Despite well-preserved capillary oxygenation increased lactate/pyruvate ratios reflecting impaired cytosolic redox state suggested deranged liver energy balance, possibly due to the O2 requirements of gluconeogenesis.

Santak, Borislav; Radermacher, Peter; Adler, Jens; Iber, Thomas; Rieger, Karen M; Wachter, Ulrich; Vogt, Josef; Georgieff, Michael; Trager, Karl

1998-01-01

206

Continuous cardiac output and left atrial pressure monitoring by long time interval analysis of the pulmonary artery pressure waveform: proof of concept in dogs.  

PubMed

We developed a technique to continuously (i.e., automatically) monitor cardiac output (CO) and left atrial pressure (LAP) by mathematical analysis of the pulmonary artery pressure (PAP) waveform. The technique is unique to the few previous related techniques in that it jointly estimates the two hemodynamic variables and analyzes the PAP waveform over time scales greater than a cardiac cycle wherein wave reflections and inertial effects cease to be major factors. First, a 6-min PAP waveform segment is analyzed so as to determine the pure exponential decay and equilibrium pressure that would eventually result if cardiac activity suddenly ceased (i.e., after the confounding wave reflections and inertial effects vanish). Then, the time constant of this exponential decay is computed and assumed to be proportional to the average pulmonary arterial resistance according to a Windkessel model, while the equilibrium pressure is regarded as average LAP. Finally, average proportional CO is determined similar to invoking Ohm's law and readily calibrated with one thermodilution measurement. To evaluate the technique, we performed experiments in five dogs in which the PAP waveform and accurate, but highly invasive, aortic flow probe CO and LAP catheter measurements were simultaneously recorded during common hemodynamic interventions. Our results showed overall calibrated CO and absolute LAP root-mean-squared errors of 15.2% and 1.7 mmHg, respectively. For comparison, the root-mean-squared error of classic end-diastolic PAP estimates of LAP was 4.7 mmHg. On future successful human testing, the technique may potentially be employed for continuous hemodynamic monitoring in critically ill patients with pulmonary artery catheters. PMID:19057003

Xu, Da; Olivier, N Bari; Mukkamala, Ramakrishna

2009-02-01

207

Preoperative cardiac risk assessment in geriatric patients with hip fractures: an orthopedic surgeons' perspective.  

PubMed

Hip fracture is one of the most common orthopedic conditions and is associated with significant morbidity and mortality. With a progressively aging population, the annual incidence of hip fracture is expected to increase substantially. Emerging evidence suggests that early surgery (<24 h) minimizes complications secondary to immobilization, including orthostatic pneumonia and venous thromboembolism. Delayed surgical repair (>48 h) has been consistently demonstrated to be associated with an increased risk of 30-day and 1-year mortality. Nonetheless, early surgery necessitates a shorter time for preoperative medical preparation, in particular cardiac assessment. Patients who undergo emergent orthopedic surgery are therefore at greater risk of perioperative cardiac events than those who undergo elective surgery. In addition, the prompt triage system for preoperative cardiac assessment not only identifies patients at high risk of perioperative cardiac complications but also reduces unnecessary cardiac consultations for low-risk patients. We review the current recommendations for preoperative cardiac assessment adapted for patients with hip fracture and describe our current triage system for preoperative cardiac consultation. PMID:21057998

Siu, C W; Sun, N C H; Lau, T W; Yiu, K H; Leung, F; Tse, H F

2010-12-01

208

Assessment and Impact of Cardiac Fibrosis on Atrial Fibrillation.  

PubMed

Fibrosis is an essential component of structural remodeling that accompanies different cardiovascular disease conditions. In cardiac arrhythmias, fibrosis plays an important role in creating the necessary substrate for these arrhythmias to persist. Non-invasive evaluation of the arrhythmia substrate has seen significant advancements in the past several years. Cardiac MRI characterizes tissue changes including fibrosis and scarring and has seen its role expand significantly in cardiac electrophysiology. We have used late-gadolinium enhancement MRI (LGE-MRI) to study tissue changes in the left atrium of patients with atrial fibrillation (AF) and demonstrated its utility in identifying poor responders to catheter ablation, as well as its association with stroke risk and significant sinus node dysfunction. Following ablation, we also studied atrial scarring and demonstrated the utility of scar imaging in guiding repeat ablation procedures. PMID:24950676

Akoum, Nazem; Marrouche, Nassir

2014-08-01

209

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

210

Role Of Cardiac Mri In The Assessment Of Nonischemic Cardiomyopathies  

PubMed Central

In this review, we will highlight the role of late gadolinium enhancement, along with other strengths available by cardiac MRI, in determining the underlying etiology of various nonischemic cardiomyopathies. Furthermore, we will also emphasize how late gadolinium enhancement may serve as a novel risk stratification tool to further impact patient care.

Nabi, Faisal

2013-01-01

211

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

212

Reproducibility of the exponential rise technique of CO 2 rebreathing for measuring P v CO 2 and C v CO 2 to non-invasively estimate cardiac output during incremental, maximal treadmill exercise  

Microsoft Academic Search

The purpose of this study was to determine the reproducibility of the indirect Fick method for the measurement of mixed venous carbon dioxide partial pressure ( P vCO 2) and venous carbon dioxide content ( C vCO 2) for estimation of cardiac output ( Q c), using the exponential rise method of carbon dioxide rebreathing, during non-steady-state treadmill exercise. Ten

W. Todd Cade; Sharmila R. Nabar; Randall E. Keyser

2004-01-01

213

Cardiac toxicity in breast cancer patients: from a fractional point of view to a global assessment.  

PubMed

When focusing on heart disease, most available studies split the two different parts of the adjuvant treatment, i.e., systemic therapies and radiation therapy, making it difficult to implement efficient strategies for preventing treatment-induced cardiac toxicity. This paper reviews the current understanding of treatments-induced cardiac toxicity in a global approach. Many factors should be considered when assessing the cardiac hazard. Treatment-related risk factors include heart dose exposure, chemotherapy, targeted agents such as HER2 inhibitors, but also endocrine agents, or anesthetic procedure. Patients' characteristics should also be taken into account. Age, menopausal status, stress, previous history of cardiac disease, genetic profile, and body mass index could all impact on cardiac function after adjuvant therapies. Cardiac toxicity should not be analyzed as the consequence of a specific therapy, but should be considered as the result of additive or supra-additive toxicities. By this way, it will be possible to implement new strategies for preventing treatment-induced cardiac toxicity. PMID:20864260

Chargari, Cyrus; Kirov, Krassen M; Bollet, Marc A; Magné, Nicolas; Védrine, Lionel; Cremades, Serge; Beuzeboc, Philippe; Fourquet, Alain; Kirova, Youlia M

2011-06-01

214

Assessment of cardiac iron by MRI susceptometry and R2* in patients with thalassemia.  

PubMed

A magnetic resonance imaging cardiac magnetic susceptometry (MRI-CS) technique for assessing cardiac tissue iron concentration based on phase mapping was developed. Normal control subjects (n=9) and thalassemia patients (n=13) receiving long-term blood transfusion therapy underwent MRI-CS and MRI measurements of the cardiac relaxation rate R2*. Using MRI-CS, subepicardium and subendocardium iron concentrations were quantified exploiting the hemosiderin/ferritin iron specific magnetic susceptibility. The average of subepicardium and subendocardium iron concentrations and R2* of the septum were found to be strongly correlated (r=0.96, P<.0001), and linear regression analysis yielded CIC (microg Fe/g(wet tissue))=(6.4+/-0.4).R2* (septum) (s(-1)) - (120+/-40). The results demonstrated that septal R2* indeed measures cardiac iron level. PMID:20061110

Wang, Zhiyue J; Fischer, Roland; Chu, Zili; Mahoney, Donald H; Mueller, Brigitta U; Muthupillai, Raja; James, Ellen B; Krishnamurthy, Rajesh; Chung, Taylor; Padua, Eric; Vichinsky, Elliott; Harmatz, Paul

2010-04-01

215

Assessment of Cardiac Iron by MRI Susceptometry and R2* in Patients with Thalassemia  

PubMed Central

An MRI cardiac magnetic susceptometry (MRI-CS) technique for assessing cardiac tissue iron concentration based on phase mapping was developed. Normal control subjects (n=9) and thalassemia patients (n = 13) receiving long-term blood transfusion therapy underwent MRI-CS and MRI measurements of the cardiac relaxation rate R2*. Using MRI-CS, subepicardium and subendocardium iron concentrations were quantified exploiting the hemosiderin/ferritin iron specific magnetic susceptibility. The average of subepicardium and subendocardium iron concentrations and R2* of the septum were found to be strongly correlated (r=0.96, p<0.0001), and linear regression analysis yielded CIC (?g Fe/g wet tissue) = (6.4 ± 0.4) · R2* septum (s-1) - (120 ± 40). The results demonstrated that septal R2* indeed measures cardiac iron level.

Wang, Zhiyue J.; Fischer, Roland; Chu, Zili; Mahoney, Donald H.; Mueller, Brigitta U.; Muthupillai, Raja; James, Ellen B.; Krishnamurthy, Rajesh; Chung, Taylor; Padua, Eric; Vichinsky, Elliott; Harmatz, Paul

2010-01-01

216

Economic input-output life-cycle assessment of trade between Canada and the United States.  

PubMed

With increasing trade liberalization, attempts at accounting for environmental impacts and energy use across the manufacturing supply chain are complicated by the predominance of internationally supplied resources and products. This is particularly true for Canada and the United States, the world's largest trading partners. We use an economic input-output life-cycle assessment (EIO-LCA) technique to estimate the economy-wide energy intensity and greenhouse gas (GHG) emissions intensity for 45 manufacturing and resource sectors in Canada and the United States. Overall, we find that U.S. manufacturing and resource industries are about 1.15 times as energy-intensive and 1.3 times as GHG-intensive as Canadian industries, with significant sector-specific discrepancies in energy and GHG intensity. This trend is mainly due to a greater direct reliance on fossil fuels for many U.S. industries, in addition to a highly fossil-fuel based electricity mix in the U.S. To account for these differences, we develop a 76 sector binational EIO-LCA model that implicitly considers trade in goods between Canada and the U.S. Our findings show that accounting for trade can significantly alter the results of life-cycle assessment studies, particularly for many Canadian manufacturing sectors, and the production/consumption of goods in one country often exerts significant energy- and GHG-influences on the other. PMID:17396636

Norman, Jonathan; Charpentier, Alex D; MacLean, Heather L

2007-03-01

217

Assessing use-dependent inhibition of the cardiac Na ± current (I Na) in the PatchXpress automated patch clamp  

Microsoft Academic Search

IntroductionThe cardiac Na+ current (INa) underlies the rapid depolarization of the cardiac myocyte, and block of the current slows cardiac conduction and increases the risk of ventricular arrhythmia. A feature of Na+ channel block termed use-dependence is important to the assessment of blocking potency. We developed a robust automated patch clamp assay to rapidly and routinely assess the use-dependent block

Jacob R. Penniman; David C. Kim; Joseph J. Salata; John P. Imredy

2010-01-01

218

Direct recording of cardiac output- and venous return-curves in the dog heart-lung preparation for a graphical analysis of the effects of cardioactive drugs.  

PubMed

The dog heart-lung preparations were prepared. The "equilibrium point", which could be defined as the point at which the cardiac output (CO)-curve and the venous return (VR)-curve crossed, when the CO and VR were plotted against the right atrial pressure, was recorded directly by utilizing an X-Y recorder. The CO-curve was obtained, as a locus of the equilibrium point, by raising and lowering the level of blood in the venous reservoir (competence test). The meaning of the procedure was shown to increase or decrease the mean systemic pressure, and to cause the corresponding parallel shift in the VR-curve. The VR-curve was obtained by changing myocardial contractility. When heart failure was induced by pentobarbital or by chloroform, the equilibrium point shifted downwards to the right, depicting the VR-curve. During development of the failure, the slopes of CO-curves decreased gradually. Effects of cinobufagin and norepinephrine were also analyzed. Utilization of the X-Y recorder enabled us to settle the uniform experimental conditions more easily, and to follow the effects of drugs continuously on a diagram equating the CO- and VR-curves (Gyton's scheme). PMID:731938

Ishikawa, N; Taki, K; Hojo, Y; Hagino, Y; Shigei, T

1978-09-01

219

Metal-enhanced fluorescent biomarkers for cardiac risk assessment  

NASA Astrophysics Data System (ADS)

In this presentation we describe a novel methodology for ultra-sensitive fluorescence immunoassays based on a new class of fluorescent biomarkers, which are strongly enhanced by nano-size metallic particles. Specifically, we discuss development of the immunoassay on the surfaces coated with metallic particles for high sensitivity detection of cardiac markers. This technology will allow detection of the biomarkers in serum and blood without separation and amplification steps. We present an experimental platform that uses front-face excitation in total internal reflection mode for efficient rejection of background fluorescence.

Matveeva, Evgenia; Gryczynski, Zygmunt; Malicka, Joanna B.; Gryczynski, Ignacy; Lakowicz, Joseph R.

2004-06-01

220

Assessment of cardiac motion effects on the fiber architecture of the human heart in vivo.  

PubMed

The use of diffusion tensor imaging (DTI) for studying the human heart in vivo is very challenging due to cardiac motion. This paper assesses the effects of cardiac motion on the human myocardial fiber architecture. To this end, a model for analyzing the effects of cardiac motion on signal intensity is presented. A Monte-Carlo simulation based on polarized light imaging data is then performed to calculate the diffusion signals obtained by the displacement of water molecules, which generate diffusion weighted (DW) images. Rician noise and in vivo motion data obtained from DENSE acquisition are added to the simulated cardiac DW images to produce motion-induced datasets. An algorithm based on principal components analysis filtering and temporal maximum intensity projection (PCATMIP) is used to compensate for motion-induced signal loss. Diffusion tensor parameters derived from motion-reduced DW images are compared to those derived from the original simulated DW images. Finally, to assess cardiac motion effects on in vivo fiber architecture, in vivo cardiac DTI data processed by PCATMIP are compared to those obtained from one trigger delay (TD) or one single phase acquisition. The results showed that cardiac motion produced overestimated fractional anisotropy and mean diffusivity as well as a narrower range of fiber angles. The combined use of shifted TD acquisitions and postprocessing based on image registration and PCATMIP effectively improved the quality of in vivo DW images and subsequently, the measurement accuracy of fiber architecture properties. This suggests new solutions to the problems associated with obtaining in vivo human myocardial fiber architecture properties in clinical conditions. PMID:23797241

Wei, Hongjiang; Viallon, Magalie; Delattre, Benedicte M A; Wang, Lihui; Pai, Vinay M; Wen, Han; Xue, Hui; Guetter, Christoph; Croisille, Pierre; Zhu, Yuemin

2013-10-01

221

Noninvasive Cardiac Flow Assessment Using High Speed Magnetic Resonance Fluid Motion Tracking  

PubMed Central

Cardiovascular diseases can be diagnosed by assessing abnormal flow behavior in the heart. We introduce, for the first time, a magnetic resonance imaging-based diagnostic that produces sectional flow maps of cardiac chambers, and presents cardiac analysis based on the flow information. Using steady-state free precession magnetic resonance images of blood, we demonstrate intensity contrast between asynchronous and synchronous proton spins. Turbulent blood flow in cardiac chambers contains asynchronous blood proton spins whose concentration affects the signal intensities that are registered onto the magnetic resonance images. Application of intensity flow tracking based on their non-uniform signal concentrations provides a flow field map of the blood motion. We verify this theory in a patient with an atrial septal defect whose chamber blood flow vortices vary in speed of rotation before and after septal occlusion. Based on the measurement of cardiac flow vorticity in our implementation, we establish a relationship between atrial vorticity and septal defect. The developed system has the potential to be used as a prognostic and investigative tool for assessment of cardiac abnormalities, and can be exploited in parallel to examining myocardial defects using steady-state free precession magnetic resonance images of the heart.

Wong, Kelvin Kian Loong; Kelso, Richard Malcolm; Worthley, Stephen Grant; Sanders, Prashanthan; Mazumdar, Jagannath; Abbott, Derek

2009-01-01

222

Can general circulation models be assessed and their output enhanced with drifter data?  

NASA Astrophysics Data System (ADS)

Drifter data from the Gulf of Mexico are used to assess and enhance the output of a primitive equation general circulation model. The analysis is made in a 450 km × 450 km open subdomain encompassing a Loop Current ring. The model velocity field is compared with position data from four drifters at the drogue depth of 50 m using geometrical orthogonal functions (GOF). An Eulerian velocity field is reconstructed from the model velocity field and drifter velocities. This reconstructed velocity improves 8-day numerical trajectories relative to the model field by at least an order of magnitude, as quantified by two Lagrangian error metrics referenced to the real drifter paths. An Eulerian metric that compares the two fields, however, does not exceed 7% for the 20-day assessment period. Thus the drifter data may be reproduced with modest impact on the model velocity. Enhancement of the model velocity field is determined by two tests: the ability of the GOF velocity field to (1) improve the forecast of drifter positions using only a posteriori data and (2) improve the forecast of withheld drifter data. Using a posteriori data, the 20-day temporal mean of the position error is improved for all drifters by 87-89% for 6-hour and 26-38% for 30-hour forecasts. For 6 days, a withheld drifter is 35-40 km from a drifter whose velocity is used in the reconstructed velocity field. The temporal mean of the position error during this period is improved by 20% for 6-hour and 26% for 30-hour forecasts.

Toner, M.; Kirwan, A. D.; Kantha, L. H.; Choi, J. K.

2001-09-01

223

Automated and manufacturer independent assessment of the battery status of implanted cardiac pacemakers by electrocardiogram analysis  

Microsoft Academic Search

According to international standards, cardiac pacemakers have to indicate the status of their batteries upon magnet application by specific stimulation patterns. The purpose of this study has been to assess whether this concept can be used as a basis for automated and manufacturer independent examination of the depletion level of pacemakers in the framework of a collaborative telemedical pacemaker follow-up

G. Schreier; D. Hayn; A. Kollmann; D. Scherr; P. Lercher; B. Rotman; W. Klein

2004-01-01

224

New method for assessing cardiac parasympathetic activity using 24 hour electrocardiograms  

Microsoft Academic Search

Cardiac parasympathetic activity was assessed using 24 hour electrocardiographic recordings by measuring the incidence of larger changes in successive RR intervals, which in normal subjects occur frequently but irregularly. In 25 normal subjects the mean number of times per hour in which the change in successive RR interval was greater than 50 ms was 150-250 during waking and 350-450 during

D J Ewing; J M Neilson; P Travis

1984-01-01

225

The ultrasonic assessment of radial, longitudinal and circumferential cardiac strain in normal pigs  

Microsoft Academic Search

Background: Ultrasound Strain Rate Imaging (SRI) is a technique that is used to assess regional myocardial function. To date, only the radial strain could be measured in a porcine model because the deformation could only be detected along the ultrasound image line in parasternal views. Nevertheless, the longitudinal and circumferential strain can contain a lot of information about cardiac (patho)

Stian Langeland; Sofie Coenen; Ming Wu; Frank Rademakers; J. D'hooge

2005-01-01

226

Ultrasonography assessment of vocal cords mobility in children after cardiac surgery  

PubMed Central

Objectives Upper airway obstruction after pediatric cardiac surgery is not uncommon. In the cardiac surgical population, an important etiology is vocal cord paresis or paralysis following extubation. In this study, we aimed to evaluate the feasibility and accuracy of ultrasonography (US) assessment of the vocal cords mobility and compare it to fiber-optic laryngoscope (FL). Material and methods A prospective pilot study has been conducted in Pediatric Cardiac ICU (PCICU) at King Abdulaziz Cardiac Center (KACC) from the 1st of June 2009 till the end of July 2010. Patients who had cardiac surgery manifested with significant signs of upper airway obstruction were included. Each procedure was performed by different operators who were blinded to each other report. Results of invasive (FL) and non-invasive ultrasonography (US) investigations were compared. Results Ten patients developed persistent significant upper airway obstruction after cardiac surgery were included in the study. Their mean ± SEM of weight and age were 4.6 ± 0.4 kg and 126.4 ± 51.4 days, respectively. All patients were referred to bedside US screening for vocal cord mobility. The results of US were compared subsequently with FL findings. Results were identical in nine (90%) patients and partially different in one (10%). Six patients showed abnormal glottal movement while the other four patients demonstrated normal vocal cords mobility by FL. Sensitivity of US was 100% and specificity of 80%. Conclusion US assessment of vocal cord is simple, non-invasive and reliable tool to assess vocal cords mobility in the critical care settings. This screening tool requires skills that can be easily obtained.

Shaath, Ghassan A.; Jijeh, Abdulraouf; Alkurdi, Ahmad; Ismail, Sameh; Elbarbary, Mahmoud; Kabbani, Mohamed S.

2012-01-01

227

Cardiac magnetic resonance for prognostic assessment: present applications and future directions.  

PubMed

Cardiac magnetic resonance is increasingly used in clinical practice for both diagnostic and prognostic purposes. In the field of ischemic heart disease, perfusion imaging permits the assessment of ischemia, which is strongly related to future cardiac events and mortality. Late gadolinium enhancement is also associated with the prognosis and can be used as a marker of functional recovery. Cardiac magnetic resonance also permits the detection of microvascular obstruction and infarct hemorrhage, both related to an adverse outcome. In non-ischemic heart disease, the presence of late gadolinium enhancement is linked to mortality and hard events. Finally, coronary angiography, as well as new techniques, such as T1 mapping, may also have a prognostic role. PMID:24754461

Doltra, Adelina; Schneeweis, Christopher; Fleck, Eckart; Kelle, Sebastian

2014-06-01

228

Effects of reduced rebreathing time, in spontaneously breathing patients, on respiratory effort and accuracy in cardiac output measurement when using a partial carbon dioxide rebreathing technique: a prospective observational study  

Microsoft Academic Search

Introduction  New technology using partial carbon dioxide rebreathing has been developed to measure cardiac output. Because rebreathing\\u000a increases respiratory effort, we investigated whether a newly developed system with 35 s rebreathing causes a lesser increase\\u000a in respiratory effort under partial ventilatory support than does the conventional system with 50 s rebreathing. We also investigated\\u000a whether the shorter rebreathing period affects the

Kazuya Tachibana; Hideaki Imanaka; Muneyuki Takeuchi; Tomoyo Nishida; Yuji Takauchi; Masaji Nishimura

2005-01-01

229

Oklahoma's Timber Industry: An Assessment of Timber Product Output and Use, 1996.  

National Technical Information Service (NTIS)

In 1996, roundwood output from Oklahoma's forests totaled 113 million cubic feet. Mill byproducts generated from primary manufacturers was 42 million cubic feet. Almost all plant residue was used primarily for fuel and fiber products. Saw logs were the le...

M. Howell T. G. Johnson

1998-01-01

230

Computerized assessment of coronary calcified plaques in CT images of a dynamic cardiac phantom  

NASA Astrophysics Data System (ADS)

Motion artifacts in cardiac CT are an obstacle to obtaining diagnostically usable images. Although phase-specific reconstruction can produce images with improved assessability (image quality), this requires that the radiologist spend time and effort evaluating multiple image sets from reconstructions at different phases. In this study, ordinal logistic regression (OLR) and artificial neural network (ANN) models were used to automatically assign assessability to images of coronary calcified plaques obtained using a physical, dynamic cardiac phantom. 350 plaque images of 7 plaques from five data sets (heart rates 60, 60, 70, 80, 90) and ten phases of reconstruction were obtained using standard cardiac CT scanning parameters on a Phillips Brilliance 64-channel clinical CT scanner. Six features of the plaques (velocity, acceleration, edge-based volume, threshold-based volume, sphericity, and standard deviation of intensity) as well as mean feature values and heart rate were used for training the OLR and ANN in a round-robin re-sampling scheme based on training and testing groups with independent plaques. For each image, an ordinal assessability index rating on a 1-5 scale was assigned by a cardiac radiologist (D.B.) for use as a "truth" in training the OLR and ANN. The mean difference between the assessability index truth and model-predicted assessability index values was +0.111 with SD=0.942 for the OLR and +0.143 with SD=0.916 for the ANN. Comparing images from the repeat 60 bpm scans gave concordance correlation coefficients (CCCs) of 0.794 [0.743, 0.837] (value, 95% CI) for the radiologist assigned values, 0.894 [0.856, 0.922] for the OLR, and 0.861 [0.818, 0.895] for the ANN. Thus, the variability of the OLR and ANN assessability index values appear to lie within the variability of the radiologist assigned values.

Rodgers, Zachary B.; King, Martin; Giger, Maryellen L.; Vannier, Michael; Bardo, Dianna M. E.; Suzuki, Kenji; Lan, Li

2008-04-01

231

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

232

Noninvasive Assessment of Tissue Heating During Cardiac Radiofrequency Ablation Using MRI Thermography  

PubMed Central

Background Failure to achieve properly localized, permanent tissue destruction is a common cause of arrhythmia recurrence after cardiac ablation. Current methods of assessing lesion size and location during cardiac radiofrequency ablation are unreliable or not suited for repeated assessment during the procedure. MRI thermography could be used to delineate permanent ablation lesions because tissue heating above 50°C is the cause of permanent tissue destruction during radiofrequency ablation. However, image artifacts caused by cardiac motion, the ablation electrode, and radiofrequency ablation currently pose a challenge to MRI thermography in the heart. In the current study, we sought to demonstrate the feasibility of MRI thermography during cardiac ablation. Methods and Results An MRI-compatible electrophysiology catheter and filtered radiofrequency ablation system was used to perform ablation in the left ventricle of 6 mongrel dogs in a 1.5-T MRI system. Fast gradient-echo imaging was performed before and during radiofrequency ablation, and thermography images were derived from the preheating and postheating images. Lesion extent by thermography was within 20% of the gross pathology lesion. Conclusions MR thermography appears to be a promising technique for monitoring lesion formation and may allow for more accurate placement and titration of ablation, possibly reducing arrhythmia recurrences.

Kolandaivelu, Aravindan; Zviman, Menekhem M.; Castro, Valeria; Lardo, Albert C.; Berger, Ronald D.; Halperin, Henry R.

2010-01-01

233

Non-invasive measurement of cardiac output by whole-body bio-impedance during dobutamine stress echocardiography: Clinical implications in patients with left ventricular dysfunction and ischaemia  

Microsoft Academic Search

Objectives: To compare non-invasive determination of cardiac index (CI) by whole body electrical bioimpedance using the NICaS apparatus and Doppler echocardiography, and the role of cardiac power index (Cpi) and total peripheral resistance index (TPRi) calculation during dobutamine stress echocardiography (DSE). Subjects and methods: We enrolled 60 consecutive patients undergoing DSE. Patients were prospectively divided into 3 groups: Group 1

Marina Leitman; Edgar Sucher; Edo Kaluski; Ruth Wolf; Eli Peleg; Yaron Moshkovitz; Olga Milo-Cotter; Zvi Vered; Gad Cotter

234

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

PubMed

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

2012-12-01

235

Resource and Output Equity as a Mechanism for Assessing Educational Opportunity in Korean Middle School Education  

ERIC Educational Resources Information Center

Korea is recognized as a high-performing country in international achievement studies; however, many researchers in and outside Korea have been worried about the existing gaps between high-socioeconomic and low-socioeconomic (SES) students in both student achievement and educational resources. We analyzed the resource and output equity of Korean…

Houck, Eric A.; Eom, Moonyoung

2012-01-01

236

Assessment of severe reperfusion injury with T2* cardiac MRI in patients with acute myocardial infarction  

Microsoft Academic Search

BackgroundIn patients with acute myocardial infarction, restoration of coronary flow by primary coronary intervention (PCI) can lead to profound ischaemia-reperfusion injury with detrimental effects on myocardial salvage. Non-invasive assessment of interstitial myocardial haemorrhage by T2* cardiac MRI (T2*-CMR) provides a novel and specific biomarker of severe reperfusion injury which may be of prognostic value.ObjectiveTo characterise the determinants of acute ischaemia-reperfusion

Declan P ORegan; Ben Ariff; Clare Neuwirth; Yvonne Tan; Giuliana Durighel; Stuart A Cook

2010-01-01

237

Non-invasive assessment of cardiac hemodynamics in patients with advanced cancer and with chronic heart failure: a pilot feasibility study  

PubMed Central

Introduction Relationships between cardiac pressure and volume have been suggested as markers of cardiac contractility; parameters include stroke work and the maximal rate of pressure rise during isovolumic contraction (dP/dtmax). Patients with cancer often display dyspnea and fatigue. These are also frequent symptoms in patients with chronic heart failure (HF). The reasons for similar symptoms in cancer patients are unknown. Using the novel Nexfin Finapres technique, we sought to assess measures of cardiac performance in patients with cancer and compare these values with those from control subjects and patients with chronic HF. Material and methods We prospectively studied 98 patients (control n = 18, chronic HF n = 37, advanced pancreatic or colorectal cancer n = 43) and assessed blood pressure (BP), stroke volume (SV), cardiac output (CO), and dP/dtmax at rest. Results All parameters of interest could be assessed using the Nexfin Finapres technique with SV and CO being significantly higher in patients with cancer than in controls (both p < 0.05). The SV was significantly higher in patients with chronic HF than in controls (p < 0.05). In patients with cancer, SV correlated with age (r = –0.45, p < 0.01) and body weight (r = +0.55, p = 0.0001). In chronic HF, SV declined with increasing age (r = –0.49, p < 0.01); in control subjects, SV increased with increasing body weight (r = +0.57, p = 0.01). Conclusions Patients with cancer tended to display elevated BP, CO, SV, and dP/dtmax as compared to control subjects and patients with HF. These findings may reveal an elevated risk for cardiovascular diseases in this group.

Lainscak, Mitja; Kung, Thomas; Cramer, Larissa; Fulster, Susann; Pelzer, Uwe; Hildebrandt, Bert; Sandek, Anja; Schefold, Joerg C.; Rauchhaus, Mathias; Doehner, Wolfram; Anker, Stefan D.

2013-01-01

238

Validation of On-Orbit Methodology for the Assessment of Cardiac Function and Changes in the Circulating Volume Using Ultrasound and Braslet-M Occlusion Cuffs  

NASA Technical Reports Server (NTRS)

The objective of this joint U.S. - Russian project was the development and validation of an in-flight methodology to assess a number of cardiac and vascular parameters associated with circulating volume and its manipulation in long-duration space flight. Responses to modified Valsalva and Mueller maneuvers were measured by cardiac and vascular ultrasound (US) before, during, and after temporary volume reduction by means of Braslet-M thigh occlusion cuffs (Russia). Materials and Methods: The study protocol was conducted in 14 sessions on 9 ISS crewmembers, with an average exposure to microgravity of 122 days. Baseline cardiovascular measurements were taken by echocardiography in multiple modes (including tissue Doppler of both ventricles) and femoral and jugular vein imaging on the International Space Station (ISS). The Braslet devices were then applied and measurements were repeated after >10 minutes. The cuffs were then released and the hemodynamic recovery process was monitored. Modified Valsalva and Mueller maneuvers were used throughout the protocol. All US data were acquired by the HDI-5000 ultrasound system aboard the ISS (ATL/Philips, USA) during remotely guided sessions. The study protocol, including the use of Braslet-M for this purpose, was approved by the ISS Human Research Multilateral Review Board (HRMRB). Results: The effects of fluid sequestration on a number of echocardiographic and vascular parameters were readily detectable by in-flight US, as were responses to respiratory maneuvers. The overall volume status assessment methodology appears to be valid and practical, with a decrease in left heart lateral E (tissue Doppler) as one of the most reliable measures. Increase in the femoral vein cross-sectional areas was consistently observed with Braslet application. Other significant differences and trends within the extensive cardiovascular data were also observed. (Decreased - RV and LV preload indices, Cardiac Output, LV E all maneuvers, LV Stroke Volume). Conclusions: This Study: 1) Addressed specific aspects of operational space medicine and space physiology, including assessment of circulating volume disturbances 2) Expanded the applications of diagnostic ultrasound imaging and Doppler techniques in microgravity. 3) Used respiratory maneuvers against the background of acute circulating volume manipulations which appear to enhance our ability to noninvasively detect volume-dependency in a number of cardiac and vascular parameters. 4) Determined that Tei index is not clinically changed therefore contractility not altered in the face of reduced preload. 5) Determined that increased Femoral Vein Area indicating blood being sequestered in lower extremities correlates with reduced preload and cardiac output. 6) That Braslet may be the only feasible means of acutely treating high pressure pulmonary edema in reduced gravity environments.

Hamilton, Douglas; Sargsyan, Ashot E.; Ebert, Douglas; Duncan, Michael; Bogomolov, Valery V.; Alferova, Irina V.; Matveev, Vladimir P.; Dulchavsky, Scott A.

2010-01-01

239

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

Microsoft Academic Search

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

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

2005-01-01

240

Low-carbon building assessment and multi-scale input-output analysis  

NASA Astrophysics Data System (ADS)

Presented as a low-carbon building evaluation framework in this paper are detailed carbon emission account procedures for the life cycle of buildings in terms of nine stages as building construction, fitment, outdoor facility construction, transportation, operation, waste treatment, property management, demolition, and disposal for buildings, supported by integrated carbon intensity databases based on multi-scale input-output analysis, essential for low-carbon planning, procurement and supply chain design, and logistics management.

Chen, G. Q.; Chen, H.; Chen, Z. M.; Zhang, Bo; Shao, L.; Guo, S.; Zhou, S. Y.; Jiang, M. M.

2011-01-01

241

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

242

Nuclear cardiac imaging for the assessment of myocardial viability  

PubMed Central

An important aspect of the diagnostic and prognostic work-up of patients with ischaemic cardiomyopathy is the assessment of myocardial viability. Patients with left ventricular dysfunction who have viable myocardium are the patients at highest risk because of the potential for ischaemia but at the same time benefit most from revascularisation. It is important to identify viable myocardium in these patients, and radionuclide myocardial scintigraphy is an excellent tool for this. Single-photon emission computed tomography perfusion scintigraphy (SPECT), whether using 201thallium, 99mTc-sestamibi, or 99mTc- tetrofosmin, in stress and/or rest protocols, has consistently been shown to be an effective modality for identifying myocardial viability and guiding appropriate management. Metabolic and perfusion imaging with positron emission tomography radiotracers frequently adds additional information and is a powerful tool for predicting which patients will have an improved outcome from revascularisation. New techniques in the nuclear cardiology field, such as attenuation corrected SPECT, dual isotope simultaneous acquisition (DISA) SPECT and gated FDG PET are promising and will further improve the detection of myocardial viability. Also the combination of multislice computed tomography scanners with PET opens possibilities of adding coronary calcium scoring and noninvasive coronary angiography to myocardial perfusion imaging and quantification. ImagesFigure 1Figure 2Figure 3

Slart, R.H.J.A.; Bax, J.J.; van der Wall, E.E.; van Veldhuisen, D.J.; Jager, P.L.; Dierckx, R.A.

2005-01-01

243

Regional assessment of cardiac left ventricular myocardial function via MRI statistical features.  

PubMed

Automating the detection and localization of segmental (regional) left ventricle (LV) abnormalities in magnetic resonance imaging (MRI) has recently sparked an impressive research effort, with promising performances and a breadth of techniques. However, despite such an effort, the problem is still acknowledged to be challenging, with much room for improvements in regard to accuracy. Furthermore, most of the existing techniques are labor intensive, requiring delineations of the endo- and/or epi-cardial boundaries in all frames of a cardiac sequence. The purpose of this study is to investigate a real-time machine-learning approach which uses some image features that can be easily computed, but that nevertheless correlate well with the segmental cardiac function. Starting from a minimum user input in only one frame in a subject dataset, we build for all the regional segments and all subsequent frames a set of statistical MRI features based on a measure of similarity between distributions. We demonstrate that, over a cardiac cycle, the statistical features are related to the proportion of blood within each segment. Therefore, they can characterize segmental contraction without the need for delineating the LV boundaries in all the frames. We first seek the optimal direction along which the proposed image features are most descriptive via a linear discriminant analysis. Then, using the results as inputs to a linear support vector machine classifier, we obtain an abnormality assessment of each of the standard cardiac segments in real-time. We report a comprehensive experimental evaluation of the proposed algorithm over 928 cardiac segments obtained from 58 subjects. Compared against ground-truth evaluations by experienced radiologists, the proposed algorithm performed competitively, with an overall classification accuracy of 86.09% and a kappa measure of 0.73. PMID:24184708

Afshin, Mariam; Ben Ayed, Ismail; Punithakumar, Kumaradevan; Law, Max; Islam, Ali; Goela, Aashish; Peters, Terry; Shuo Li

2014-02-01

244

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

245

Non-invasive assessment of perioperative myocardial cell damage by circulating cardiac troponin T.  

PubMed Central

Troponin T is a unique cardiac antigen which is continuously released from infarcting myocardium. Its cardiospecificity as a marker protein might be particularly useful in assessing myocardial cell damage in patients undergoing cardiac surgery. Therefore, circulating troponin T was measured in serial blood samples from 56 patients undergoing cardiac surgery and in two control groups--22 patients undergoing minor orthopaedic surgery and 12 patients undergoing lung surgery by median sternotomy. In both control groups no troponin T could be detected, whereas activities of creatine kinase were raised in all 12 lung surgery controls and activities of the MB isoenzyme were raised in five of the 12 patients in the lung surgery group and in four of the 22 patients in the orthopaedic surgery group, respectively. All the patients undergoing coronary artery bypass grafting (n = 47) and cardiac surgery for other reasons (n = 9) had detectable concentrations of troponin T. Five patients had perioperative myocardial infarction detected as new Q waves and R wave reductions. In these five patients troponin T release persisted and serum concentrations (5.5-23 micrograms/l) reached a peak on the fourth postoperative day. In the 51 patients without perioperative myocardial infarction serum concentrations and the release kinetics of troponin T depended on the duration of cardiac arrest. In patients in whom aortic cross clamping was short troponin T increased slightly on the first postoperative days; in patients with longer periods of aortic cross clamping troponin T concentrations were higher and remained so beyond the fifth postoperative day. In patients with non-specific changes on the electrocardiogram troponin T concentrations were significantly higher on days 1 and 4 after operation than in patients with normal postoperative electrocardiograms(11.2 (5) and 4.5 (2.6) v 8.2 (3.4) and 2.9 (1.6) 1microg/l). Serum concentrations of troponin T showed some myocardial cell damage in every patient undergoing cardiac surgery. The persistent increases that were more common in patients with longer periods of cardiac arrest must have been caused by damage to the contractile apparatus. These results suggest that perioperative myocardial cell necrosis may be more common than indicated by changes of the QRS complex on the electrocardiogram.

Katus, H. A.; Schoeppenthau, M.; Tanzeem, A.; Bauer, H. G.; Saggau, W.; Diederich, K. W.; Hagl, S.; Kuebler, W.

1991-01-01

246

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

PubMed

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) >or=0.0% and/or turbulence slope (TS)assessment indicates a frequent impairment of cardiac autonomic nervous system in SSc patients. Moreover, older age in these patients and especially PH are independent significant predictors of cardiac autonomic dysfunction. PMID:19101049

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

2010-06-11

247

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

248

Comparison of simultaneous and sequential SPECT imaging for discrimination tasks in assessment of cardiac defects  

PubMed Central

Simultaneous rest perfusion/fatty-acid metabolism studies have the potential to replace sequential rest/stress perfusion studies for the assessment of cardiac function. Simultaneous acquisition has the benefits of increased signal and lack of need for patient stress, but is complicated by cross-talk between the two radionuclide signals. We consider a simultaneous rest 99mTc-sestamibi/123I-BMIPP imaging protocol in place of the commonly-used sequential rest/stress 99mTc-sestamibi protocol. The theoretical precision with which the severity of a cardiac defect and the transmural extent of infarct can be measured is computed for simultaneous and sequential SPECT imaging, and their performance is compared for discriminating (1) degrees of defect severity, and (2) sub-endocardial from transmural defects. We consider cardiac infarcts, for which reduced perfusion and metabolism are observed. From an information perspective, simultaneous imaging is found to yield comparable or improved performance compared with sequential imaging for discriminating both severity of defect and transmural extent of infarct, for three defects of differing location and size.

Trott, CM; Ouyang, J; El Fakhri, G

2011-01-01

249

Comparison of simultaneous and sequential SPECT imaging for discrimination tasks in assessment of cardiac defects  

NASA Astrophysics Data System (ADS)

Simultaneous rest perfusion/fatty-acid metabolism studies have the potential to replace sequential rest/stress perfusion studies for the assessment of cardiac function. Simultaneous acquisition has the benefits of increased signal and lack of need for patient stress, but is complicated by cross-talk between the two radionuclide signals. We consider a simultaneous rest 99mTc-sestamibi/123I-BMIPP imaging protocol in place of the commonly used sequential rest/stress 99mTc-sestamibi protocol. The theoretical precision with which the severity of a cardiac defect and the transmural extent of infarct can be measured is computed for simultaneous and sequential SPECT imaging, and their performance is compared for discriminating (1) degrees of defect severity and (2) sub-endocardial from transmural defects. We consider cardiac infarcts for which reduced perfusion and metabolism are observed. From an information perspective, simultaneous imaging is found to yield comparable or improved performance compared with sequential imaging for discriminating both severity of defect and transmural extent of infarct, for three defects of differing location and size.

Trott, C. M.; Ouyang, J.; El Fakhri, G.

2010-11-01

250

A new methodological approach to assess cardiac work by pressure–volume and stress–length relations in patients with aortic valve stenosis and dilated cardiomyopathy  

Microsoft Academic Search

In experimental animals, cardiac work is derived from pressure–volume area and analyzed further using stress–length relations.\\u000a Lack of methods for determining accurately myocardial mass has until now prevented the use of stress–length relations in patients.\\u000a We hypothesized, therefore, that not only pressure–volume loops but also stress–length diagrams can be derived from cardiac\\u000a volume and cardiac mass as assessed by cardiac

P. Alter; H. Rupp; M. B. Rominger; K. J. Klose; B. Maisch

2008-01-01

251

[Pre-operative cardiac assessment in non-cardiac surgery: a frequent dilemma simplified by a decision tree].  

PubMed

In patients undergoing non-cardiac surgery, cardiac events are the most common cause of perioperative morbidity and mortality. It is often difficult to choose adequate cardiologic examinations before surgery. This paper, inspired by the guidelines of the European and American societies of cardiology (ESC, AHA, ACC), discusses the place of standard ECG, echocardiography, treadmill or bicycle ergometer and pharmacological stress testing in preoperative evaluations. The role of coronary angiography and prophylactic revascularization will also be discussed. Finally, we provide a decision tree which will be helpful to both general practitioners and specialists. PMID:20572354

Sierro, C; Iglesias, J F; Eeckhout, E; Vogt, P

2010-06-01

252

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

253

Accounting for the biogeochemical cycle of nitrogen in input-output life cycle assessment.  

PubMed

Nitrogen is indispensable for sustaining human activities through its role in the production of food, animal feed, and synthetic chemicals. This has encouraged significant anthropogenic mobilization of reactive nitrogen and its emissions into the environment resulting in severe disruption of the nitrogen cycle. This paper incorporates the biogeochemical cycle of nitrogen into the 2002 input-output model of the U.S. economy. Due to the complexity of this cycle, this work proposes a unique classification of nitrogen flows to facilitate understanding of the interaction between economic activities and various flows in the nitrogen cycle. The classification scheme distinguishes between the mobilization of inert nitrogen into its reactive form, use of nitrogen in various products, and nitrogen losses to the environment. The resulting inventory and model of the US economy can help quantify the direct and indirect impacts or dependence of economic sectors on the nitrogen cycle. This paper emphasizes the need for methods to manage the N cycle that focus not just on N losses, which has been the norm until now, but also include other N flows for a more comprehensive view and balanced decisions. Insight into the N profile of various sectors of the 2002 U.S. economy is presented, and the inventory can also be used for LCA or Hybrid LCA of various products. The resulting model is incorporated in the approach of Ecologically-Based LCA and available online. PMID:23869533

Singh, Shweta; Bakshi, Bhavik R

2013-08-20

254

Weighted DPOAE input/output-functions: a tool for automatic assessment of hearing loss in clinical application.  

PubMed

2f1-f2 distortion product otoacoustic emission (DPOAE) input/output functions were recorded in 796 ears with sensorineural hearing loss at up to 50 frequencies between 500 Hz and 8 kHz in a wide level range from L2 = 20 to L2 = 65 dB SPL at up to 10 levels ("scissor paradigm", L1 = 0.4 L2 + 39, f2/f1 = 1.2). DPOAEs were accepted as valid for signal-to-noise ratios (SNR) only if they exceeded 6 dB. To assess the DPOAE threshold, DPOAE input/output functions (L2--DPOAE sound pressure diagram) were subject to linear regression and extrapolation; the point of intersection with the L2 coordinate was then interpreted as DPOAE threshold [1]. The linear fit of the function pDP(L2) = a + bL2 (whereby a and b represent the threshold and the slope of the DPOAE growth, respectively), reflects compression and sensitivity of the cochlear amplifier. Using a weighted least mean square error (LMSE) regression, more than 70% of the DPOAE I/O functions of the data set can be used for the threshold estimation. High correlation and relatively small differences between objectively estimated DPOAE threshold and subjectively determined hearing threshold of pure-tone audiograms prove that the weighted extrapolation of DPOAE I/O functions can be a valuable clinical tool for the objective assessment of cochlear hearing loss. PMID:12868334

Oswald, Johann A; Janssen, Thomas

2003-01-01

255

The estimation of cardiac output by the Nexfin device is of poor reliability for tracking the effects of a fluid challenge.  

PubMed

ABSTRACT: INTRODUCTION: The Nexfin device estimates arterial pressure by the volume clamp method through a finger pneumatic cuff. It also allows to estimate cardiac index (CInoninv) by pulse contour analysis of the non-invasive arterial pressure curve. We evaluated the ability of the device to track changes in cardiac index induced by a fluid challenge. METHODS: We included 45 patients for whom a volume expansion (500 mL of saline infused over 30 min) was planned. The volume expansion-induced changes in cardiac index measured by transpulmonary thermodilution (CIinv, PiCCO device) and in CInoninv were recorded. RESULTS: In seven patients, the Nexfin could not record the arterial curve due to finger hypoperfusion. Considering both the values obtained before and after volume expansion (n = 76 pairs of measurements), the bias (lower and upper limits of agreement) between CIinv and CInoninv was 0.2 (-1.8 to 2.2) L/min/m2. The mean change in CInoninv was 10 ± 11%. The percentage error of CInoninv was 57%. The correlation between the changes in CIinv and CInoninv observed during volume expansion was significant (P = 0.0002) with an r2 = 0.31. CONCLUSIONS: The estimation of CI by the Nexfin device in critically ill patients is not reliable, neither for estimating absolute values of CI nor for tracking its changes during volume expansion. PMID:23107227

Monnet, Xavier; Picard, Fabien; Lidzborski, Elsa; Mesnil, Malcie; Duranteau, Jacques; Richard, Christian; Teboul, Jean-Louis

2012-10-29

256

The estimation of cardiac output by the Nexfin device is of poor reliability for tracking the effects of a fluid challenge  

PubMed Central

Introduction The Nexfin device estimates arterial pressure by the volume clamp method through a finger pneumatic cuff. It also allows to estimate cardiac index (CInoninv) by pulse contour analysis of the non-invasive arterial pressure curve. We evaluated the ability of the device to track changes in cardiac index induced by a fluid challenge. Methods We included 45 patients for whom a volume expansion (500 mL of saline infused over 30 min) was planned. The volume expansion-induced changes in cardiac index measured by transpulmonary thermodilution (CIinv, PiCCO device) and in CInoninv were recorded. Results In seven patients, the Nexfin could not record the arterial curve due to finger hypoperfusion. Considering both the values obtained before and after volume expansion (n = 76 pairs of measurements), the bias (lower and upper limits of agreement) between CIinv and CInoninv was 0.2 (-1.8 to 2.2) L/min/m2. The mean change in CInoninv was 10 ± 11%. The percentage error of CInoninv was 57%. The correlation between the changes in CIinv and CInoninv observed during volume expansion was significant (P = 0.0002) with an r2 = 0.31. Conclusions The estimation of CI by the Nexfin device in critically ill patients is not reliable, neither for estimating absolute values of CI nor for tracking its changes during volume expansion.

2012-01-01

257

An Adaptive Regional Input-Output Model and its Application to the Assessment of the Economic Cost of Katrina  

NASA Astrophysics Data System (ADS)

Recent events, especially natural disasters, have raised concerns about the response of local economies to large exogenous shocks. Clearly, our ability to assess the total economic costs of large-scale events like the Katrina's landfall is very poor, and numerous questions needs to be investigated. Among them, the taking into account of complex interactions within the economic system --- between economic sectors or regions --- is the topic of intense research. Several studies have approached these issues using Input-Output models, which are powerful tools to assess how a shock, on one or several sectors, propagate into the economy through intermediate consumption and demand. These models, however, have two main short-comings. First, since they do not take into account productive capacity, they cannot assess the consequence of a shock on the supply-side. Second, they do not allow for flexibility in the economic system in that producers and consumers cannot respond to a lack in input. The presentation will describe an adaptive regional input-output model, which aims at answering the previous concerns through the introduction of an hybrid modelling methodology. This model takes into account economic propagations through both intermediate demands and production shortages, and also represents the response of economic agents facing production shortages. An application of this model to the evaluation of the economic cost of Katrina will be demonstrated, highlighting both modelling and data issues. Also, beyond a simple "best-guess" assessment, systematic sensitivity analyses will be presented, allowing for an evaluation of the accuracy one can expect from such a model.

Hallegatte, S.

2006-12-01

258

Empirical comparison of process and economic input-output life cycle assessment in service industries.  

PubMed

The study fills a gap in existing literature by comparing process-based and E10-based life cycle assessment (LCA) methods empirically in service industries. Despite the numerous methodological differences, the methods were found mostly to produce the same environmentally significant processes for the case organization: the use of electricity in the premises, the construction of the premises, the business travel by cars, the heating of the premises, and the business flights. However, the process-based LCA could not be used to assess the environmental impacts of purchased services properly. The study also recognized most of the theoretical differences listed in the literature, and found the ones related to the cut-offs in purchased services, the price inhomogeneity, and the industry-atypical electricity production have the greatest influence on results. PMID:17154018

Junnila, Seppo I

2006-11-15

259

Interstitial Myocardial Fibrosis Assessed as Extracellular Volume Fraction with Low-Radiation-Dose Cardiac CT  

PubMed Central

Purpose: To develop a cardiac computed tomographic (CT) method with which to determine extracellular volume (ECV) fraction, with cardiac magnetic resonance (MR) imaging as the reference standard. Materials and Methods: Study participants provided written informed consent to participate in this institutional review board–approved study. ECV was measured in healthy subjects and patients with heart failure by using cardiac CT and cardiac MR imaging. Paired Student t test, linear regression analysis, and Pearson correlation analysis were used to determine the relationship between cardiac CT and MR imaging ECV values and clinical parameters. Results: Twenty-four subjects were studied. There was good correlation between myocardial ECV measured at cardiac MR imaging and that measured at cardiac CT (r = 0.82, P < .001). As expected, ECV was higher in patients with heart failure than in healthy control subjects for both cardiac CT and cardiac MR imaging (P = .03, respectively). For both cardiac MR imaging and cardiac CT, ECV was positively associated with end diastolic and end systolic volume and inversely related to ejection fraction (P < .05 for all). Mean radiation dose was 1.98 mSv ± 0.16 (standard deviation) for each cardiac CT acquisition. Conclusion: ECV at cardiac CT and that at cardiac MR imaging showed good correlation, suggesting the potential for myocardial tissue characterization with cardiac CT. © RSNA, 2012

Nacif, Marcelo Souto; Kawel, Nadine; Lee, Jason J.; Chen, Xinjian; Yao, Jianhua; Zavodni, Anna; Sibley, Christopher T.; Lima, Joao A. C.; Liu, Songtao

2012-01-01

260

Liver Stiffness Assessment by Tagged MRI of Cardiac-induced Liver Motion  

PubMed Central

Cirrhosis is an important and growing public health problem, affecting millions of Americans and many more people internationally. A pathological hallmark of the progression to cirrhosis is the development of liver fibrosis, so that monitoring the appearance and progression of liver fibrosis can be used to guide therapy. We here report a method to use magnetization-tagged magnetic resonance imaging (MRI) to measure the cardiac-induced motion and deformation in the liver, as a means for noninvasively assessing liver stiffness, which is related to fibrosis. The initial results show statistically significant differences between healthy and cirrhotic subjects in the direct comparisons of the maximum displacement (mm), and the maximum (P1) and minimum (P2) 2D strains, through the cardiac cycle (3.514 ± 0.793, 2.184 ± 0.611; 0.116 ± 0.043, 0.048 ± 0.011; ?0.094 ± 0.020, ?0.041 ± 0.015; healthy, cirrhosis, respectively; p < 0.005 for all). There are also significant differences in the displacement-normalized P1 and P2 strains (mm?1) (0.030 ± 0.008, 0.017 ± 0.007; ?0.024 ± 0.006, ?0.013 ± 0.004; healthy, cirrhosis, respectively; p < 0.005 for all). Therefore, this noninvasive imaging-based method is a promising means to assess liver stiffness using clinically available imaging tools.

Chung, Sohae; Breton, Elodie; Mannelli, Lorenzo; Axel, Leon

2010-01-01

261

A Prospective Assessment of the Effect of Aminophylline Therapy on Urine Output and Inflammation in Critically Ill Children  

PubMed Central

Background: Aminophylline, an established bronchodilator, is also purported to be an effective diuretic and anti-inflammatory agent. However, the data to support these contentions are scant. We conducted a prospective, open-label, single arm, single center study to assess the hypothesis that aminophylline increases urine output and decreases inflammation in critically ill children. Methods: Children less than 18?years of age admitted to the pediatric intensive care unit who were prescribed aminophylline over a 24-h period were eligible for study. The use and dosing of aminophylline was independent of the study and was at the discretion of the clinical team. Data analyzed consisted of demographics, diagnoses, medications, and markers of pulmonary function, renal function, and inflammation. Data were collected at baseline and at 24-h after aminophylline initiation with primary outcomes of change in urine output and inflammatory cytokine concentrations. Results: Thirty-five patients were studied. Urine output increased significantly with aminophylline use [median increase 0.5?mL/kg/h (IQR: ?0.3, 1.3), p?=?0.05] while blood urea nitrogen and creatinine concentrations remained unchanged. Among patients with elevated C-reactive protein concentrations, levels of both interleukin-6 (IL-6) and IL-10 decreased at 24?h of aminophylline therapy. There were no significant differences in pulmonary compliance or resistance among patients invasively ventilated at both time points. Side effects of aminophylline were detected in 7 of 35 patients. Conclusion: Although no definitive conclusions can be drawn from this study, aminophylline may be a useful diuretic and effective anti-inflammatory medication in critically ill children. Given the incidence of side effects, the small sample size and the uncontrolled study design, further study is needed to inform the appropriate use of aminophylline in these children.

Tamburro, Robert F.; Thomas, Neal J.; Ceneviva, Gary D.; Dettorre, Michael D.; Brummel, Gretchen L.; Lucking, Steven E.

2014-01-01

262

Development of a Novel Output Value for Quantitative Assessment in Methylated DNA Immunoprecipitation-CpG Island Microarray Analysis  

PubMed Central

In DNA methylation microarray analysis, quantitative assessment of intermediate methylation levels in samples with various global methylation levels is still difficult. Here, specifically for methylated DNA immunoprecipitation-CpG island (CGI) microarray analysis, we developed a new output value. The signal log ratio reflected the global methylation levels, but had only moderate linear correlation (r = 0.72) with the fraction of DNA molecules immunoprecipitated. By multiplying the signal log ratio using a coefficient obtained from the probability value that took account of signals in neighbouring probes, its linearity was markedly improved (r = 0.94). The new output value, Me value, reflected the global methylation level, had a strong correlation also with the fraction of methylated CpG sites obtained by bisulphite sequencing (r = 0.88), and had an accuracy of 71.8 and 83.8% in detecting completely methylated and unmethylated CGIs. Analysis of gastric cancer cell lines using the Me value showed that methylation of CGIs in promoters and gene bodies was associated with low and high, respectively, gene expression. The degree of demethylation of promoter CGIs after 5-aza-2'-deoxycytidine treatment had no association with that of induction of gene expression. The Me value was considered to be useful for analysis of intermediate methylation levels of CGIs.

Yamashita, Satoshi; Hosoya, Kosuke; Gyobu, Ken; Takeshima, Hideyuki; Ushijima, Toshikazu

2009-01-01

263

Light-output response of the plastic scintillator for the Mars Science Laboratory (MSL) Radiation Assessment Detector (RAD)  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD) onboard NASA's Mars Science Laboratory (MSL) rover mission has been designed to detect a wide range of particle types (charged and neutral) and energies on the Mars surface. The BC432m plastic scintillator coupled to PIN photodiodes has been used as a neutron detector as well as an anticoincidence shield for the RAD instrument. We present an experimental study of the non-linear light-output response of the BC432m for protons and neutrons beams. The experimental results have been compared to the parametric formula based on the theoretical work of Birks and Chou. Furthermore, a comparison between the quenching effect found in the BC432m and in other inorganic scintillators (CsI:Tl) used in the RAD instrument has been performed.

Martin, C.; Boehm, E.; Kortmann, O.; Boettcher, S.; Wimmer-Schweingruber, R. F.; Burmeister, S.; Ehresmann, B.; Hassler, D. M.; Zeitlin, C.; Posner, A.; Neal, K.; Rafkin, S.; Weigle, E.; Reitz, G.

2008-12-01

264

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.

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

2012-01-01

265

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

PubMed

Juvenile idiopathic arthritis (JIA) is the most common rheumatologic disorder of childhood. It is a group of diseases characterized by chronic synovitis and associated with many extra-articular manifestations including cardiac and pulmonary involvement. Cardiac involvement as pericarditis, myocarditis and valvular disease is common in JIA. There are, however, few descriptions concerning systolic and diastolic functions of the left ventricle (LV) and the development of lung disease in children with JIA. The study was carried out to detect the cardiac and pulmonary involvement and to study the systolic and diastolic function of the left ventricle in a group of children with juvenile idiopathic arthritis. Forty-five children with JIA without any cardiac or pulmonary symptoms and 30 age- and sex-matched controls were included in the study. M-mode, two-dimensional and pulsed Doppler echocardiography (ECHO) was performed on 36 patients. Tissue Doppler ECHO examination was performed on 24 patients to assess systolic and diastolic functions of left ventricle. Pulmonary function tests: Forced vital capacity (FVC%), the predicted forced expiratory volume in the first second (FEV(1)%) and FEV(1)/FVC ratio and peak expiratory flow (PEF), total lung capacity (TLC) and residual volume (RV), carbon monoxide diffusing capacity of the lung (DLCO) and DLCO/alveolar volume (VA) were evaluated in 32 patients. Informed consent was obtained from all children's parents. The study protocol was approved by ethical committee of Faculty of Medicine, Assiut University. In this study, children with JIA had higher systolic and diastolic blood pressures, resting heart rate, left ventricle systolic size and volume (4.35 ± 0.68 vs. 3.92 ± 0.28, P value = 0.02). On Doppler and tissue Doppler analysis, the JIA group had lower peak early filling velocity (E, m/s), higher peak atrial filling velocity (A, m/s) and prolonged diastolic E and A waves deceleration times and isovolumic relaxation time (IRT) compared to control. Regarding pulmonary function tests, children with JIA showed significant decrease in FVC, PEF, Pimax, Pemax and DLCO compared to normal controls. This decrease was not related to age, height or weight of these patients. There was significant inverse correlation between lung function parameters and the rheumatoid factor titer, erythrosedimentation rate, disease duration and the duration of methotrexate use (P < 0.01). Despite of an asymptomatic cardiopulmonary status, significant systolic and diastolic functional abnormalities exist in children with JIA. Also, both restrictive and obstructive lung impairments were found. PMID:20658239

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

2012-01-01

266

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

PubMed

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

2013-08-01

267

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.

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

2009-01-01

268

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

PubMed

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

2014-05-01

269

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.

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

2014-01-01

270

Rapid pediatric cardiac assessment of flow and ventricular volume with compressed sensing parallel imaging volumetric cine phase-contrast MRI  

PubMed Central

Purpose Quantification of cardiac flow and ventricular volumes comprise essential goals of many congenital heart MRI examinations, often requiring acquisition of multiple two-dimensional phase contrast (2DPC) and bright blood cine SSFP planes. Scan prescription however, is lengthy and highly reliant on an imager well-versed in structural heart disease. Though also lengthy, 3D time-resolved phase-contrast (4DPC) MRI yields global flow patterns and is simpler to prescribe. We therefore sought to accelerate 4DPC and determine whether equivalent flow and volume measurements could be extracted. Materials and Methods 4DPC was modified for higher acceleration with compressed-sensing. Custom software was developed to process 4DPC images. With IRB-approval and HIPAA-compliance, we studied 29 patients referred for congenital cardiac MRI, who underwent a routine clinical protocol including cine short-axis stack SSFP and 2DPC, followed by contrast-enhanced 4DPC. To compare quantitative measurements, Bland-Altman analysis, paired t-tests, and F-tests were used. Results Ventricular end-diastolic, end-systolic and stroke volumes obtained from 4DPC and SSFP were well-correlated (?=0.91–0.95, r2=0.83–0.90), with no statistically significant difference. Ejection fractions were well-correlated in a subpopulation that underwent higher-resolution compressed-sensing 4DPC (?=0.88, r2=0.77). 4DPC and 2DPC flow rates were also well-correlated (?=0.90, r2=0.82). Excluding ventricles with valvular insufficiency, cardiac outputs derived from outlet valve flow and stroke volumes were more consistent by 4DPC than by 2DPC and SSFP. Conclusion Combined parallel imaging and compressed sensing can be applied to 4DPC. With custom software, flow and ventricular volumes may be extracted with comparable accuracy to SSFP and 2DPC. Further, cardiac outputs were more consistent by 4DPC.

Hsiao, Albert; Lustig, Michael; Alley, Marcus T.; Murphy, Mark; Chan, Frandics P.; Herfkens, Robert J.; Vasanawala, Shreyas S.

2012-01-01

271

High-dose interleukin 2-induced myocarditis: can myocardial damage reversibility be assessed by cardiac MRI?  

PubMed

High-dose interleukin 2 (HD-IL2) is one of the therapeutic options for patients with metastatic renal cell carcinoma. In well-selected patients with favorable clinical and pathologic features, it offers impressive response and potential long-term remission. It also has a place for treatment for metastatic malignant melanoma and in adoptive cell therapy. However, it is known for its intensive course and toxicities. Myocarditis is one of the known complications of this treatment and can pose a diagnostic challenge to treating oncologists because of its nonspecific and similar presentation to acute coronary syndrome (ACS). We report 3 short cases of HD-IL2-related myocarditis, which were either missed or misdiagnosed as ACS using conventional assessment but subsequently accurately diagnosed by cardiac magnetic resonant imaging (CMR). We discussed the clinical presentation of these cases and demonstrated the diagnostic advantage of CMR compared with standard investigations including its superior capability to assess myocardial reversibility, which has important short-term and long-term implications. The use of CMR also avoided unnecessary invasive intervention such as coronary angiogram in all 3 patients. These example cases call for effort to conduct prospective research to assess and confirm the utility of CMR, thus informing a more effective management pathway for immune-related myocarditis in HD-IL2 and other cancer immunotherapy. PMID:24810642

Chow, Shien; Cove-Smith, Laura; Schmitt, Matthias; Hawkins, Robert

2014-06-01

272

Nurse-led risk assessment/management clinics reduce predicted cardiac morbidity and mortality in claudicants.  

PubMed

Nurse-led assessment/management of risk factors is effective in many chronic medical conditions. We aimed to evaluate whether this finding was true for patients with intermittent claudication and to analyze its impact on patient-reported quality of life and predicted mortality due to coronary heart disease. We prospectively studied a series of 78 patients (51 men; median age, 65 years [IQR: 56-74 years]), diagnosed with intermittent claudication and referred to a nurse-led risk assessment/management clinic (NLC) from a consultant-led vascular surgical clinic. The NLC used clinical care pathways to manage antiplatelet medication, smoking cessation, hyperlipidemia, hypertension, and diabetes and to provide exercise advice. All patients were reassessed at a 3 months. Medication compliance, smoking status, fasting lipid profiles, blood pressure, and HbA1c were recorded. Disease-specific quality of life was assessed using King's College VascuQoL and predicted cardiac morbidity and mortality were calculated using the PROCAM and Framingham risk scores. We found that NLC enrollment produced an antiplatelet and a statin compliance of 100%, a smoking cessation rate of 17% (9 patients) and significant improvements in total cholesterol (median, 5.2-4.5 mmol/l), LDL (median, 3.1-2.5 mmol/l) and triglyceride (median, 1.7-1.4 mmol/l) levels. Significant disease-specific quality of life improvements and significant reduction in both the PROCAM (14% to 10%) and Framingham (14% to 11%) coronary risk scores were observed. Providing care at NLCs for claudicants is effective in assessing and managing risk factors, improves disease-specific quality of life and reduces predicted morbidity and mortality due to coronary heart disease. PMID:19022170

Hatfield, Josephine; Gulati, Sumit; Abdul Rahman, Morhisham N A; Coughlin, Patrick A; Chetter, Ian C

2008-12-01

273

Cardiac shock wave therapy: assessment of safety and new insights into mechanisms of tissue regeneration.  

PubMed

Although low-energy extracorporeal cardiac shock wave (ECSW) therapy represents an attractive non-invasive treatment option for ischaemic heart disease, the precise mechanisms of its action and influence on the cardiac tissue remain obscure. The goal of this study was to evaluate the effects of SW application on cardiac function and structure. Four-month-old Fisher 344 rats were subjected to ECSW therapy. Echocardiographic measurements of cardiac function were performed at baseline and at 1 and 3 months after treatment. Signs of inflammation, apoptosis and fibrosis were evaluated by immunohistochemistry in the control and treated hearts. ECSW application did not provoke arrhythmia or increase the troponin-I level. At all time points, the left ventricular ejection fraction and fractional shortening remained stable. Histological analysis revealed neither differences in the extracellular matrix collagen content nor the presence of fibrosis; similarly, there were no signs of inflammation. Moreover, a population of cardiac cells that responded eagerly to ECSW application in the adult heart was identified; c-kit-positive, Ki67-positive, orthochromatic cells, corresponding to cardiac primitive cells, were 2.65-fold more numerous in the treated myocardium. In conclusion, non-invasive ECSW therapy is a safe and effective way of activating cardiac stem cells and myocardial regeneration. Because many factors influence cellular turnover in the ischaemic myocardium during the course of ischaemic heart disease, cardiac remodelling, and heart failure progression, studies to identify the optimal treatment time are warranted. PMID:21790971

Di Meglio, Franca; Nurzynska, Daria; Castaldo, Clotilde; Miraglia, Rita; Romano, Veronica; De Angelis, Antonella; Piegari, Elena; Russo, Sergio; Montagnani, Stefania

2012-04-01

274

A time-saving method to assess power output at lactate threshold in well-trained and elite cyclists.  

PubMed

The purpose of this study was to examine the relationship between lactate threshold (LT) as a percentage of maximal oxygen consumption (V[Combining Dot Above]O2max) and power output at LT (LTW) and also to investigate to what extent V[Combining Dot Above]O2max, oxygen cost of cycling (CC), and maximal aerobic power (MAP) determine LTW in cycling to develop a new time-saving model for testing LTW. To do this, 108 male competitive cyclists with an average V[Combining Dot Above]O2max of 65.2 ± 7.4 ml·kg·min and an average LTW of 274 ± 43 W were tested for V[Combining Dot Above]O2max, LT %V[Combining Dot Above]O2max, LTW, MAP, and CC on a test ergometer cycle. The product of MAP and individual LT in %V[Combining Dot Above]O2max was found to be a good determinant of LTW (R = 0.98, p < 0.0001). However, LT in %V[Combining Dot Above]O2max was found to be a poor determinant of LTW (R = 0.39, p < 0.0001). Based on these findings, we have suggested a new time-saving method for calculating LTW in well-trained cyclists. The benefits from this model come both from tracking LTW during training interventions and from regularly assessing training status in competitive cyclists. Briefly, this method is based on the present findings that LTW depends on LT in %V[Combining Dot Above]O2max, V[Combining Dot Above]O2max, and CC and may after an initial test session reduce the time for the subsequent testing of LTW by as much as 50% without the need for blood samples. PMID:23942166

Støren, Øyvind; Rønnestad, Bent R; Sunde, Arnstein; Hansen, Joar; Ellefsen, Stian; Helgerud, Jan

2014-03-01

275

Clinical trial enrollers vs. nonenrollers: The Cardiac Arrhythmia Suppression Trial (CAST) Recruitment and Enrollment Assessment in Clinical Trials (REACT) project  

Microsoft Academic Search

The Recruitment and Enrollment Assessment in Clinical Trials (REACT) was a National Heart, Lung, and Blood Institute (NHLBI)-sponsored substudy to the Cardiac Arrhythmia Suppression Trial (CAST). Two-hundred-sixty (260) patients who enrolled in CAST and 140 partially or fully eligible patients who did not enroll were compared across several parameters, including demographic variables, disease severity, psychosocial functioning, health beliefs, recruitment experience,

Larry Gorkin; Eleanor B. Schron; Kathy Handshaw; Steven Shea; Marguerite R. Kinney; Martha Branyon; Jeanne Campion; J. Thomas Bigger; Susan C. Sylvia; Jeanette Duggan; Mario Stylianou; Scott Lancaster; David K. Ahern; Michael J. Follick

1996-01-01

276

Acid perfusion test: does it have a role in the assessment of non cardiac chest pain?  

PubMed Central

Using 24 hour pH monitoring as a reference standard, the usefulness of the acid perfusion (AP) test in predicting gastro-oesophageal reflux disease (GORD) was assessed in 71 non-cardiac chest pain (NCCP) patients and 23 endoscopic oesophagitis patients. Of the 71 NCCP patients, 35 had a positive AP test (of whom 20 had an abnormal 24 hour pH) and 36 had a negative AP test (of whom 14 had an abnormal 24 hour pH study). Thus, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the AP test in this group was 59%, 59%, 57%, and 61%, respectively. The corresponding values in the oesophagitis group were 85%, 67%, 94%, and 40%. In the NCCP group when heartburn alone was used as the positive criterion the PPV rose to 74%. When chest pain with or without heartburn was used, however, the PPV dropped to 38%. A 'symptom index' was used to define the number of chest pain episodes that were caused by acid reflux. Only 48% of AP test positive patients had demonstrable acid mediated chest pain. In the NCCP population with a normal oesophageal examination (1) AP test reproduction of chest pain is poorly predictive of GORD; (2) AP test reproduction of heartburn is more predictive of GORD but does not ensure that the chest pain is caused by GORD; (3) a negative AP test does not exclude GORD and (4) only 48% of AP test positive patients have demonstrable acid mediated chest pain. The ambulatory 24 hour pH test may have rendered the AP test obsolete in the assessment of GORD as the cause of NCCP.

Hewson, E G; Sinclair, J W; Dalton, C B; Wu, W C; Castell, D O; Richter, J E

1989-01-01

277

Traditional and novel methods to assess and prevent chemotherapy-related cardiac dysfunction noninvasively.  

PubMed

The field of cardio-oncology is challenged to address an ever greater spectrum of cardiotoxicity associated with combination chemotherapy, greater dose intensity, extremes of age, and enhanced patient survival which exposes more protracted risk of developing congestive heart failure (CHF). Recent reports of chemotherapy-induced hypertension as a common adverse effect of angiogenesis inhibitors and immunosuppressants clarify the need for routine blood pressure (BP) monitoring and guideline-based management of hypertension as an integral strategy to preserve LV function. Serial monitoring of radionuclide left ventricular ejection fraction (LVEF) in adults and echocardiography in children continues to provide outcome based, cost-effective prevention of CHF in high risk patients receiving chemotherapy. To optimize treatment and monitoring strategies to eliminate late-onset LV dysfunction and CHF, traditional and novel candidate methods for assessment of chemotherapy-induced LV dysfunction are reviewed. These include serial assessment of LV volume indices by gated SPECT ERNA and gated SPECT MPI, 3D echocardiography and contrast 2D echocardiography; longitudinal strain imaging, diastolic functional parameters, (123)I-MIBG, (111)In-Antimyosin antibody imaging, and (99m)Tc-Annexin V apoptosis imaging, biomarkers including troponins and BNP; genetic markers, and both functional and tissue characterization techniques with T1 weighted and T2 weighted images with cardiac magnetic resonance imaging (CMR). In our quest to optimize strategies for long-term cancer survival and prevention of CHF for patients receiving chemotherapy, rigorous modality and guideline-specific clinical outcome trials are required. A new multi-modality monitoring approach is proposed, which integrates evidence-based strengths of CMR, echocardiography, ERNA, biomarkers, and BP management for surveillance and validation of cardiotoxicity and prevention of clinical heart failure in patients receiving a broad spectrum of cancer therapies. PMID:23572315

Schwartz, Ronald G; Jain, Diwakar; Storozynsky, Eugene

2013-06-01

278

Assessment of cardiac function during mechanical circulatory support: the quest for a suitable clinical index.  

PubMed

A new index to assess left ventricular (LV) function in patients implanted with continuous flow left-ventricular assist devices (LVADs) is proposed. Derived from the pump flow signal, this index is defined as the coefficient (k) of the semilogarithmic relationship between "pseudo-ejection" fraction (pEF) and the volume discharged by the pump in diastole, (V d). pEF is defined as the ratio of the "pseudo-stroke volume" (pSV) to V d. The pseudo-stroke volume is the difference between V d and the volume discharged by the pump in systole (V s), both obtained by integrating pump flow with respect to time in a cardiac cycle. k was compared in-vivo with others two indices: the LV pressure-based index, M(TP), and the pump flow-based index, I(Q). M(TP) is the slope of the linear regression between the "triple-product" and end-diastolic pressure, EDP. The triple-product, TP = LV SP.dP/dt(max). HR, is the product of LV systolic pressure, maximum time-derivative of LV pressure, and heart rate. I(Q) is the slope of the linear regression between maximum time-derivative of pump flow, dQ/dt(max), and pump flow peak-to-peak amplitude variation, Q(P2P). To test the response of k to contractile state changes, contractility was altered through pharmacological interventions. The absolute value of k decreased from 1.354 ± 0.25 (baseline) to 0.685 ± 0.21 after esmolol infusion. The proposed index is sensitive to changes in inotropic state, and has the potential to be used clinically to assess contractile function of patients implanted with VAD. PMID:22254290

Ferreira, Antonio L; Wang, Yajuan; Gorcsan, John; Antaki, James F

2011-01-01

279

Development of a Pacemaker Monitor with Cardiac Simulator.  

National Technical Information Service (NTIS)

A cardiac pacemaker monitoring system was developed for use in testing cardiac pacemakers in RF fields. The system provided for both continuous monitoring of the pacemaker output and simulating normal cardiac activity at the pacemaker leads. Fiber optics ...

T. O. Steiner

1975-01-01

280

Parameterization of real-time 3D speckle tracking framework for cardiac strain assessment  

Microsoft Academic Search

Cross-correlation based 3D speckle tracking algorithm can be used to automatically track myocardial motion on three dimensional real-time (RT3D) echocardiography. The goal of this study was to experimentally investigate the effects of different parameters associated with such algorithm to ensure accurate cardiac strain measurements. The investigation was performed on 10 chronic obstructive pulmonary disease RT3DE cardiac ultrasound images. The following

Auranuch Lorsakul; Qi Duan; Ming Jack Po; Elsa Angelini; Shunichi Homma; Andrew F. Laine

2011-01-01

281

Safety and efficiency assessment of training Canadian cardiac surgery residents to perform aortic valve surgery  

PubMed Central

Background Research has demonstrated equivalent patient safety outcomes for various cardiac procedures when the primary surgeon was a supervised trainee. However, cardiac surgery cases have become more complex, and the Canadian cardiac surgery education model has undergone some changes. We sought to compare patient safety and efficiency of aortic valve replacement (AVR) between Canadian patients treated by senior cardiac trainees and those treated by certified cardiac surgeons. Methods We completed a single-centre, case-matched, prospectively collected and retrospectively analyzed study of AVR. Patients were matched between trainees and consultants for age, sex, New York Heart Association and Canadian Cardiovascular Society status, urgency of operation and diabetes status. Results We analyzed 1102 procedures: 624 isolated AVRs and 478 AVRs with coronary artery bypass graft (CABG). For isolated AVR, there was no significant difference in 30-d mortality (p = 0.13) or in major adverse events (p = 0.38) between the groups. In the AVR+CABG group, there was no significant difference in 30-day mortality (p = 0.10) or in the rates of major adverse events (p = 0.37) between the groups. Secondary outcomes (hospital and intensive care unit lengths of stay, valve size and type) did not differ significantly between the groups for isolated AVR or AVR+CABG. Conclusion Despite a higher-risk patient population and changes in the cardiac surgery training model, it appears that outcomes are not negatively affected when a senior trainee acts as the primary surgeon in cases of AVR.

Chen, Kuan-chin Jean; Adams, Corey; Stitt, Larry W.; Guo, L. Ray

2013-01-01

282

Piecewise nonlinear mixed-effects models for modeling cardiac function and assessing treatment effects.  

PubMed

Mixed-effects model is an efficient tool for analyzing longitudinal data. The random effects in a mixed-effects model can be used to capture the correlations among repeated measurements within a subject. Mixed effects model can be used to describe individual response profile as well as population response profile. In this manuscript, we apply mixed-effects models to the repeated measurements of cardiac function variables including heart rate, coronary flow, and left ventricle developed pressure (LVDP) in the isolated, Langendorff-perfused hearts of glutathione s-transferase P1/P2 (GSTP) gene knockout and wild-type mice. Cardiac function was measured before and during ischemia/reperfusion injury in these hearts. To describe the dynamics of each cardiac function variable during the entire experiment, we developed piecewise nonlinear mixed-effects models and a change point nonlinear mixed effect model. These models can be used to examine how cardiac function variables were altered by ischemia/reperfusion-induced injury and to compare the cardiac function variable between genetically engineered (null or transgenic) mice and wild-type mice. Hypothesis tests were constructed to evaluate the impact of deletion of GSTP gene for different cardiac function variables. These findings provide a new application for mixed-effects models in physiological and pharmacological studies of the isolated Langendorff-perfused heart. PMID:23253450

Jang, Hyejeong; Conklin, Daniel J; Kong, Maiying

2013-06-01

283

Quantitative assessment of brain microvascular and tissue oxygenation during cardiac arrest and resuscitation in pigs.  

PubMed

Cardiac arrest is associated with a very high rate of mortality, in part due to inadequate tissue perfusion during attempts at resuscitation. Parameters such as mean arterial pressure and end-tidal carbon dioxide may not accurately reflect adequacy of tissue perfusion during cardiac resuscitation. We hypothesised that quantitative measurements of tissue oxygen tension would more accurately reflect adequacy of tissue perfusion during experimental cardiac arrest. Using oxygen-dependent quenching of phosphorescence, we made measurements of oxygen in the microcirculation and in the interstitial space of the brain and muscle in a porcine model of ventricular fibrillation and cardiopulmonary resuscitation. Measurements were performed at baseline, during untreated ventricular fibrillation, during resuscitation and after return of spontaneous circulation. After achieving stable baseline brain tissue oxygen tension, as measured using an Oxyphor G4-based phosphorescent microsensor, ventricular fibrillation resulted in an immediate reduction in all measured parameters. During cardiopulmonary resuscitation, brain oxygen tension remained unchanged. After the return of spontaneous circulation, all measured parameters including brain oxygen tension recovered to baseline levels. Muscle tissue oxygen tension followed a similar trend as the brain, but with slower response times. We conclude that measurements of brain tissue oxygen tension, which more accurately reflect adequacy of tissue perfusion during cardiac arrest and resuscitation, may contribute to the development of new strategies to optimise perfusion during cardiac resuscitation and improve patient outcomes after cardiac arrest. PMID:23590519

Yu, J; Ramadeen, A; Tsui, A K Y; Hu, X; Zou, L; Wilson, D F; Esipova, T V; Vinogradov, S A; Leong-Poi, H; Zamiri, N; Mazer, C D; Dorian, P; Hare, G M T

2013-07-01

284

Gated blood-pool SPECT versus cardiac magnetic resonance imaging for the assessment of left ventricular volumes and ejection fraction  

Microsoft Academic Search

Background  We evaluated the accuracy of planar radionuclide angiography and different count-based and space-based electrocardiogram (ECG)-gated\\u000a blood-pool single-photon emission computed tomography (GBPS) algorithms for assessment of left ventricular end-diastolic volume\\u000a (LVEDV), end-systolic volume (LVESV), and ejection fraction (LVEF) compared with the gold standard of cardiac magnetic resonance\\u000a imaging (cMRI). The goal is to assess the accuracy of a recently developed GBPS

François Harel; Vincent Finnerty; Jean Grégoire; Bernard Thibault; François Marcotte; Patricia Ugolini; Paul Khairy

2010-01-01

285

Longitudinal assessment of cardiac diastolic function in HIV-infected patients.  

PubMed

Asymptomatic isolated diastolic dysfunction (DD), with normal left ventricular systolic function, may be the first indication of underlying cardiac disease in HIV-negative populations. We previously reported a high prevalence (37%) of DD among asymptomatic HIV-infected patients at low risk for AIDS and cardiovascular disease (CVD). We performed a longitudinal assessment of interval echocardiographic changes in this cohort over a four-year period. Repeat transthoracic echocardiograms (TTEs) utilized standard techniques. Sixty (of the original 91) HIV-infected patients, predominately men, underwent repeat TTE (median follow-up 3.7 years, interquartile range [IQR] 3.5, 4.0). Cohort characteristics (median; IQR) include age 42.0 (36.5, 46.0) years, HIV duration 16.4 years (8.1, 18.9), current CD4 count 572.0 cells/mm(3) (436.5, 839.0), antiretroviral therapy (ART) duration 8.1 years (4.8, 13.4) and Framingham risk score 1.0 (0.0, 2.0). DD was observed in 28/60 patients on re-evaluation (47%, 95% confidence interval [CI] 34%, 60%); 31% (11/36) of patients had new onset DD for an overall incidence of 8.2/100 person-years. On follow-up, subjects with DD were older, had a trend towards higher body mass index, hypertension and longer duration of HIV infection compared with subjects without DD. We confirmed a high prevalence of DD (47%) in asymptomatic HIV-infected patients at low risk for AIDS and CVD. PMID:22422684

Blaylock, J M; Byers, D K; Gibbs, B T; Nayak, G; Ferguson, M; Tribble, D R; Porter, C; Decker, C F

2012-02-01

286

Commutability of Possible External Quality Assessment Materials for Cardiac Troponin Measurement  

PubMed Central

Background The measurement of cardiac troponin is crucial in the diagnosis of myocardial infarction. The performance of troponin measurement is most conveniently monitored by external quality assessment (EQA) programs. The commutability of EQA samples is often unknown and the effectiveness of EQA programs is limited. Methods Commutability of possible EQA materials was evaluated. Commercial control materials used in an EQA program, human serum pools prepared from patient samples, purified analyte preparations, swine sera from model animals and a set of patient samples were measured for cTnI with 4 assays including Abbott Architect, Beckman Access, Ortho Vitros and Siemens Centaur. The measurement results were logarithm-transformed, and the transformed data for patient samples were pairwise analyzed with Deming regression and 95% prediction intervals were calculated for each pair of assays. The commutability of the materials was evaluated by comparing the logarithmic results of the materials with the limits of the intervals. Matrix-related biases were estimated for noncommutable materials. The impact of matrix-related bias on EQA was analyzed and a possible correction for the bias was proposed. Results Human serum pools were commutable for all assays; purified analyte preparations were commutable for 2 of the 6 assay pairs; commercial control materials and swine sera were all noncommutable; swine sera showed no reactivity to Vitros assay. The matrix-related biases for noncommutable materials ranged from ?83% to 944%. Matrix-related biases of the EQA materials caused major abnormal between-assay variations in the EQA program and correction of the biases normalized the variations. Conclusion Commutability of materials has major impact on the effectiveness of EQA programs for cTnI measurement. Human serum pools prepared from patient samples are commutable and other materials are mostly noncommutable. EQA programs should include at least one human serum pool to allow proper interpretation of EQA results.

Zhang, Shunli; Zeng, Jie; Zhang, Chuanbao; Li, Yilong; Zhao, Haijian; Cheng, Fei; Yu, Songlin; Wang, Mo; Chen, Wenxiang

2014-01-01

287

Assessing the suitability of input–output analysis for enhancing our understanding of potential economic effects of Peak Oil  

Microsoft Academic Search

Given recent developments on energy markets and skyrocketing oil prices, we argue for an urgent need to study the potential effects of world oil production reaching a maximum (Peak Oil) in order to facilitate the development of adaptation policies. We consider input–output (IO) modelling as a powerful tool for this purpose. However, the standard Leontief type model implicitly assumes that

Christian Kerschner; Klaus Hubacek

2009-01-01

288

Non-invasive assessment of cardiac function and pulmonary vascular resistance in an canine model of acute thromboembolic pulmonary hypertension using 4D flow cardiovascular magnetic resonance  

PubMed Central

Background The purpose of this study was to quantify right (RV) and left (LV) ventricular function, pulmonary artery flow (QP), tricuspid valve regurgitation velocity (TRV), and aorta flow (QS) from a single 4D flow cardiovascular magnetic resonance (CMR) (time-resolved three-directionally motion encoded CMR) sequence in a canine model of acute thromboembolic pulmonary hypertension (PH). Methods Acute PH was induced in six female beagles by microbead injection into the right atrium. Pulmonary arterial (PAP) and pulmonary capillary wedge (PCWP) pressures and cardiac output (CO) were measured by right heart catheterization (RHC) at baseline and following induction of acute PH. Pulmonary vascular resistance (PVRRHC) was calculated from RHC values of PAP, PCWP and CO (PVRRHC?=?(PAP-PCWP)/CO). Cardiac magnetic resonance (CMR) was performed on a 3 T scanner at baseline and following induction of acute PH. RV and LV end-diastolic (EDV) and end-systolic (ESV) volumes were determined from both CINE balanced steady-state free precession (bSSFP) and 4D flow CMR magnitude images. QP, TRV, and QS were determined from manually placed cutplanes in the 4D flow CMR flow-sensitive images in the main (MPA), right (RPA), and left (LPA) pulmonary arteries, the tricuspid valve (TRV), and aorta respectively. MPA, RPA, and LPA flow was also measured using two-dimensional flow-sensitive (2D flow) CMR. Results Biases between 4D flow CMR and bSSFP were 0.8 mL and 1.6 mL for RV EDV and RV ESV, respectively, and 0.8 mL and 4 mL for LV EDV and LV ESV, respectively. Flow in the MPA, RPA, and LPA did not change after induction of acute PAH (p?=?0.42-0.81). MPA, RPA, and LPA flow determined with 4D flow CMR was significantly lower than with 2D flow (p?cardiac function and cardiopulmonary hemodynamic parameters important in the assessment of PH.

2014-01-01

289

[Cardiac troponin-T. Diagnostic efficacy in acute myocardial infarction. Clinical and laboratory assessment].  

PubMed

Cardiac troponin-T is a subunit of the myofibrillar regulatory troponintropomiosin complex, with sufficient specificity to myocardium. In normal conditions it is absent from serum and its presence indicates lesion of the cardiac cells. The authors evaluated the analytical and clinical performance of an immunoassay for cardiac troponin-T, before its introduction in their own laboratory routine. They concluded that the test had good analytical performance, with some difficulties in practicability that can be surpassed by using a rapid bedside test for troponin-T in urgency departments, already approved by FDA in USA and available in Portugal. The diagnostic specificity and sensitivity was better than the one of the classic enzymatic markers for Acute Myocardial Infarction (AMI) but it is necessary to establish clear clinical protocols that allow its use in AMI. PMID:9632957

Miguel, M J; Amaral, T; Loureiro, J; Brito, B; Pêgo, J; Machado, H C; Gouveia, A

1998-04-01

290

Noninvasive assessment of cardiac abnormalities in experimental autoimmune myocarditis by magnetic resonance microscopy imaging in the mouse.  

PubMed

Myocarditis is an inflammation of the myocardium, but only ~10% of those affected show clinical manifestations of the disease. To study the immune events of myocardial injuries, various mouse models of myocarditis have been widely used. This study involved experimental autoimmune myocarditis (EAM) induced with cardiac myosin heavy chain (Myhc)-? 334-352 in A/J mice; the affected animals develop lymphocytic myocarditis but with no apparent clinical signs. In this model, the utility of magnetic resonance microscopy (MRM) as a non-invasive modality to determine the cardiac structural and functional changes in animals immunized with Myhc-? 334-352 is shown. EAM and healthy mice were imaged using a 9.4 T (400 MHz) 89 mm vertical core bore scanner equipped with a 4 cm millipede radio-frequency imaging probe and 100 G/cm triple axis gradients. Cardiac images were acquired from anesthetized animals using a gradient-echo-based cine pulse sequence, and the animals were monitored by respiration and pulse oximetry. The analysis revealed an increase in the thickness of the ventricular wall in EAM mice, with a corresponding decrease in the interior diameter of ventricles, when compared with healthy mice. The data suggest that morphological and functional changes in the inflamed hearts can be non-invasively monitored by MRM in live animals. In conclusion, MRM offers an advantage of assessing the progression and regression of myocardial injuries in diseases caused by infectious agents, as well as response to therapies. PMID:24998332

Massilamany, Chandirasegaran; Khalilzad-Sharghi, Vahid; Gangaplara, Arunakumar; Steffen, David; Othman, Shadi F; Reddy, Jay

2014-01-01

291

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

292

The Society of Thoracic Surgeons National Cardiac Surgery Database: Current Risk Assessment  

Microsoft Academic Search

Background. The Society of Thoracic Surgeons National Cardiac Surgery Database has recently completed gathering patient data from 1990 through 1994. Using information from more than 300,000 patients undergoing isolated coronary artery bypass grafting in this period, new risk models of operative mortality were developed.Methods. Logistic regression analysis was used to develop a risk model for each calendar year. A standard

Fred H Edwards; Frederick L Grover; A. Laurie W Shroyer; Marc Schwartz; Joseph Bero

1997-01-01

293

Radiographic assessment of dental health in middle-aged men following sudden cardiac death.  

PubMed

Poor oral health has been suggested to be a risk factor for myocardial infarction. To study if dental pathology might predispose to pre-hospital sudden cardiac death, and using a sum index of panoramic tomography findings, we compared the oral health of middle-aged (33-69 yrs) male victims (Helsinki Sudden Death Study) of sudden cardiac death (n = 117) with that of controls, who died of non-cardiac diseases (n = 63) or suffered unnatural sudden death (n = 120). The mean number of teeth was 15.2, and 17.4% of the men were edentulous. Frequent age-associated findings in dentate victims were fillings (79.9%), horizontal bone loss (72.1%), periapical lesions (45.6%), residual roots (38.2%), and vertical pockets (30.9%). In multivariate analysis with coronary heart disease risk factors and number of teeth as covariates, poor oral health was associated (p = 0.053) with the risk of sudden cardiac death along with age, smoking, and body mass index. This association was especially strong (p = 0.009) among victims < 50 yrs. PMID:16373688

Karhunen, V; Forss, H; Goebeler, S; Huhtala, H; Ilveskoski, E; Kajander, O; Mikkelsson, J; Penttilä, A; Perola, M; Ranta, H; Meurman, J H; Karhunen, P J

2006-01-01

294

Quantitative EEG Assessment of Brain Injury and Hypothermic Neuroprotection after Cardiac Arrest  

Microsoft Academic Search

In this paper we provide a quantitative electroencephalogram (EEG) analysis to study the effect of hypothermia on the neurological recovery of brain after cardiac arrest. We hypothesize that the brain injury results in a reduction in information of the brain rhythm. To measure the information content of the EEG a new measure called information quantity (IQ), which is the Shannon

Hyun-Chool Shin; Shanbao Tong; Soichiro Yamashita; Xiaofeng Jia; Romergryko G. Geocadin; Nitish V. Thakor

2006-01-01

295

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

296

Correlation between extent of myocardial fibrosis assessed by cardiac magnetic resonance and cardiac troponin T release in patients with nonischemic heart failure.  

PubMed

Persistently high cardiac troponin T (cTnT) levels reflect myocardial damage in heart failure (HF). The presence and extent of myocardial fibrosis assessed by cardiac magnetic resonance (CMR) and high levels of cTnT predict poor prognosis in various cardiomyopathies. However, the association between myocardial fibrosis and transcardiac cTnT release has not been evaluated. This study investigated the correlation between myocardial fibrosis and transcardiac cTnT release from nonischemic failing myocardium. Serum cTnT levels were measured in aortic root (Ao) and coronary sinus (CS) using highly sensitive assay (detection limit >5 ng/L) in 74 nonischemic patients with HF who underwent CMR. Transcardiac cTnT release (?cTnT [CS-Ao]) represented the difference between CS and Ao-cTnT levels. Myocardial fibrosis was quantified by late gadolinium enhancement (LGE) volume and %LGE on CMR. cTnT was detectable in 65 patients (88%), and ?cTnT (CS-Ao) levels were available (?cTnT [CS-Ao] >0 ng/L) in 60 patients (81%). LGE was observed in 42 patients (57%), and ?cTnT (CS-Ao) levels were available in 41 LGE-positive patients (98%). In patients with available cTnT release, ?cTnT (CS-Ao) levels were significantly higher in LGE-positive patients than those in LGE-negative patients (4.3 [2.2-5.5] vs 1.5 [0.9-2.6] ng/L; p = 0.001). Log (?cTnT [CS-Ao]) levels were correlated with LGE volume (r = 0.460, p = 0.003) and %LGE (r = 0.356, p = 0.03). In conclusion, the amount of transcardiac cTnT release was higher in LGE-positive patients than LGE-negative patients and correlated with the extent of LGE in nonischemic patients with HF. These results suggested that ongoing myocardial damage correlates with the presence and extent of myocardial fibrosis. PMID:24698466

Takashio, Seiji; Yamamuro, Megumi; Uemura, Tomoaki; Utsunomiya, Daisuke; Morita, Kosuke; Izumiya, Yasuhiro; Sugiyama, Seigo; Kojima, Sunao; Yamamoto, Eiichiro; Tsujita, Kenichi; Tanaka, Tomoko; Tayama, Shinji; Kaikita, Koichi; Hokimoto, Seiji; Yasuda, Osamu; Yamashita, Yasuyuki; Ogawa, Hisao

2014-05-15

297

Assessing quality in cardiac surgery: why this is necessary in the twenty-first century  

NASA Technical Reports Server (NTRS)

The cost and high-profile nature of coronary surgery means that this is an area of close public scrutiny. As much pioneering work in data collection and risk analyses has been carried out by cardiac surgeons, substantial information exists and the correct interpretation of that data is identified as an important issue. This paper considers the background and history of risk-adjustment in cardiac surgery, the uses of quality data, examines the observed/expected mortality ratio and looks at issues such as cost and reactions to outliers. The conclusion of the study is that the continuation of accurate data collection by the whole operative team and a strong commitment to constantly improving quality is crucial to its meaningful application.

Swain, J. A.; Hartz, R. S.

2000-01-01

298

Assessment of perfusion and wall-motion abnormalities and transient ischemic dilation in regadenoson stress cardiac magnetic resonance perfusion imaging.  

PubMed

Vasodilator first-pass stress cardiac magnetic resonance perfusion imaging [stress cardiac magnetic resonance (CMR)] is a reliable, noninvasive method for evaluating myocardial ischemia; however, it does not routinely evaluate metrics such as wall-motion abnormality (WMA) and transient ischemic dilation (TID). Using the new selective A2A adenosine receptor agonist regadenoson, we tested a novel protocol for assessing perfusion defects, WMA, and TID in a single stress CMR session. We evaluated 29 consecutive patients who presented for clinically indicated regadenoson stress CMR. Immediately before and after the regadenoson stress perfusion sequence, we obtained baseline and post-stress cine images in the short-axis orientation to detect worsening or newly developed WMAs. This approach also allowed evaluation of TID. Delayed-enhancement imaging was performed in the standard orientations. All patients tolerated the procedure well. Thirteen patients (45 %) had perfusion abnormalities, and four patients developed TID. Seven patients had WMAs, and three of them also had TID. Patients with TID ± WMAs had multivessel disease documented by coronary angiography. By using regadenoson to assess myocardial ischemia during stress CMR, perfusion defects, WMAs, and TID can be evaluated in a single imaging session. To our knowledge, we are the first to describe this novel approach in a vasodilator stress CMR study. PMID:24706255

Hojjati, Mohammad R; Muthupillai, Raja; Wilson, James M; Preventza, Ourania A; Cheong, Benjamin Y C

2014-06-01

299

Transcutaneous Vagus Nerve Stimulation: Retrospective Assessment of Cardiac Safety in a Pilot Study  

PubMed Central

Background: Vagus nerve stimulation has been successfully used as a treatment strategy for epilepsy and affective disorders for years. Transcutaneous vagus nerve stimulation (tVNS) is a new non-invasive method to stimulate the vagus nerve, which has been shown to modulate neuronal activity in distinct brain areas. Objectives: Here we report effects of tVNS on cardiac function from a pilot study, which was conducted to evaluate the feasibility and safety of tVNS for the treatment of chronic tinnitus. Methods: Twenty-four patients with chronic tinnitus underwent treatment with tVNS over 3–10?weeks in an open single-armed pilot study. Safety criteria and practical usability of the neurostimulating device were to investigate by clinical examination and electrocardiography at baseline and at several visits during and after tVNS treatment (week 2, 4, 8, 16, and 24). Results: Two adverse cardiac events (one classified as a severe adverse event) were registered but considered very unlikely to have been caused by the tVNS device. Retrospective analyses of electrocardiographic parameters revealed a trend toward shortening of the QRS complex after tVNS. Conclusion: To our knowledge this is one of the first studies investigating feasibility and safety of tVNS in a clinical sample. In those subjects with no known pre-existing cardiac pathology, preliminary data do not indicate arrhythmic effects of tVNS.

Kreuzer, Peter M.; Landgrebe, Michael; Husser, Oliver; Resch, Markus; Schecklmann, Martin; Geisreiter, Florian; Poeppl, Timm B.; Prasser, Sarah Julia; Hajak, Goeran; Langguth, Berthold

2012-01-01

300

Assessment of the hemodynamic changes following fluid preloading in cardiac surgery  

PubMed Central

Background: This prospective double-blind randomized study aims to study the hemodynamic changes following fluid preloading with Hydroxyethyl starch (HES) 6% (130/0.4) compared with normal saline (NS) in cardiac surgery patients. Methods: Forty patients undergoing coronary artery bypass grafting (CABG) were enrolled in this study, then they were divided in 2 equal groups, HES and NS. After fast administration of 10 mL/kg from either solutions over 5 min only, hemodynamic parameters, such as heart rate, mean arterial pressure (MAP), central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), mean pulmonary artery pressure, systemic vascular resistance, and pulmonary vascular resistance were measured every 5 min for the total duration of 40 minutes. Results: There were significant differences in the cardiac index measurements between both groups at 15 min onward; also PAOP was significantly higher in HES group at 10 min onward. CVP was higher in HES group but statistically significant at 10 min only. MAP was higher in HES group, but that was statistically significant at 40 min only. On the other hand PAP was significantly higher at 10 and 40 min. Conclusion: Fluid preloading with HES led to a significant increase in filling pressure of the left ventricle (PAOP) and cardiac index compared with NS. We believe that HES (130/0.4) could be a suitable solution for fluid preloading in CABG surgery patients. However, further studies are needed on different fluid preloading modalities with different dosing regimens.

Alsatli, Raed A.

2012-01-01

301

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.

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

2013-01-01

302

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

PubMed Central

Traditional proteomics provides static assessment of protein content, but not synthetic rates. Recently, proteome dynamics with heavy water (2H2O) was introduced, where 2H 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 2H2O in the drinking water for up to 60 days. Plasma 2H2O and myocardial 2H-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 (R2 = 0.84; P < 0.0001), values in IFM were 15% less than SSM (P < 0.001). In conclusion, administration of 2H2O 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.

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

2013-01-01

303

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

304

An analysis of implantable cardiac device reliability. The case for improved postmarketing risk assessment and surveillance.  

PubMed

Implantable cardiac devices have become the mainstay of the treatment of patients with heart disease. However, data regarding their reliability and, inferentially, safety have been called into question. We reviewed annual reports submitted to the Food and Drug Administration Office of Device Evaluation by device manufacturers from 2003 to 2007. The annual number of implantable cardiac defibrillators (ICDs) and cardiac resynchronization therapy defibrillator (CRT-D) implants, explants, and returned devices were tabulated along with the cumulative (Cum) number of implants for each device. We derived an annual explantation rate (AER) defined as the ratio of the annual number of explants less the number of normal battery depletions/Cum (×1000). From 2003 to 2007, 256,392 CRT-D and 459,300 ICD devices were implanted in the United States. The overall mean (±SD) AERs for ICD and CRT-D devices were, respectively, 49.5 (15.6) per 1000 ICD devices and 82.6 (35.5) per 1000 CRT-D devices. The AER for each device type significantly decreased over the study period (P for trend <0.001) although the AER for CRT-D devices was 38% higher than that for ICD devices (P < 0.001). On average, 20.3% of CRT-D devices and 22.6% of ICD devices were returned to the manufacturer for analysis after explantation. The rates of explanted CRT-D and ICD devices decreased from 2003 to 2007. Notwithstanding this favorable trend, the AER for CRT-D devices was higher than that for ICD devices. Improved methods for tracking individual device histories are needed for more precise estimates of the risk of device explantation for suspected malfunction. The proportion of devices returned to the manufacturer is suboptimal and needs to be improved to better understand the mechanisms of device malfunction. PMID:22668602

Laskey, Warren; Awad, Khaled; Lum, Jeremy; Skodacek, Ken; Zimmerman, Barbara; Selzman, Kimberly; Zuckerman, Bram

2012-07-01

305

Assessment of use of music by patients participating in cardiac rehabilitation.  

PubMed

The primary cause of morbidity and mortality in the United States is heart disease. It is a costly and pervasive group of disorders that effect all ages, races, and genders. Behavioral medicine and health psychology have focused on prevention and psychosocial influences of cardiovascular diseases for the past 30 years. Music therapy is a viable collaborative method in the psychosocial arena for alleviating risks and motivating rehabilitation from cardiac events. There is research to support the use of music to modulate heart health measurements such as heart rate and blood pressure, to enhance exercise programs, and to relieve stress symptoms. However, inconsistencies in the results of this research warrant continued collaboration of social scientists to find scientific means of establishing interventions with measurable outcomes. This project involved administering a music therapy survey in order to determine current use and preference for music in a cardiac rehabilitation program. Patients who were attending rehabilitation sessions in a large city hospital completed a survey on which they rated their level of use of music for exercise, relaxation, and enjoyment. The researcher also gathered information about musical preferences, musical experiences, and pertinent demographics. Patients, mostly white males over the age of 60, showed positive responses to the aesthetically pleasurable aspects of music. The use of music as a stimulus cue for exercise was decidedly absent. Nursing staff members were receptive to the project, and both staff and patients showed some interest for learning about music for therapeutic purposes. The results suggest that education about and development of music therapy in a cardiac rehabilitation program is warranted. PMID:15157124

Metzger, L Kay

2004-01-01

306

Real time assessment of RF cardiac tissue ablation with optical spectroscopy  

SciTech Connect

An optical spectroscopy approach is demonstrated allowing for critical parameters during RF ablation of cardiac tissue to be evaluated in real time. The method is based on incorporating in a typical ablation catheter transmitting and receiving fibers that terminate at the tip of the catheter. By analyzing the spectral characteristics of the NIR diffusely reflected light, information is obtained on such parameters as, catheter-tissue proximity, lesion formation, depth of penetration of the lesion, formation of char during the ablation, formation of coagulum around the ablation site, differentiation of ablated from healthy tissue, and recognition of micro-bubble formation in the tissue.

Demos, S G; Sharareh, S

2008-03-20

307

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...

308

Points to consider emerging from a mini-workshop on cardiac safety: assessing torsades de pointes liability.  

PubMed

A mini-workshop on cardiac safety focusing on assessing drug-induced Torsades de Pointes (TdP) liability was convened as part of the 6th Annual Meeting of the Safety Pharmacology Society. The purpose of this brief publication is to disseminate the salient points emanating from this workshop as a means of engaging the scientific community in the appropriate discussions needed to advance this important field of human safety. The recommendations in this publication extend those of the workshop on "Moving Towards Better Predictors of Drug-Induced Torsades de Pointes" held in November 2005 under the auspice of the International Life Sciences Institute, Health and Environmental Sciences Institute; they fall into four key areas: molecular and cellular biology underlying TdP, dynamics of periodicity, models of TdP proarrhythmia and key considerations for demonstrating utility of non-clinical models. The reader is encouraged to consider the recommendations emanating from the two workshops and align these with ongoing studies in their laboratories. The authors intend to convene a workshop in 2009/2010 to judge advancements in the field of study of drug-induced TdP and make recommendations for a focused validation of those methods holding the greatest promise of improving the predictivity of this unwanted human cardiac risk. PMID:17707127

Bass, Alan; Valentin, Jean-Pierre; Fossa, Anthony A; Volders, Paul G A

2007-01-01

309

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

310

An In Vitro Assessment of Acoustic Radiation Force Impulse Imaging for Visualizing Cardiac Radiofrequency Ablation Lesions  

PubMed Central

Introduction Lesion placement and transmurality are critical factors in the success of cardiac transcatheter radiofrequency ablation (RFA) treatments for supraventricular arrhythmias. This study investigated the capabilities of catheter transducer based acoustic radiation force impulse (ARFI) ultrasound imaging for quantifying ablation lesion dimensions. Methods and Results RFA lesions were created in vitro in porcine ventricular myocardium and imaged with an intracardiac ultrasound catheter transducer capable of acquiring spatially registered B-mode and ARFI images. The myocardium was sliced along the imaging plane and photographed. The maximum ARFI-induced displacement images of the lesion were normalized and spatially registered with the photograph by matching the surfaces of the tissue in the B-mode and photographic images. The lesion dimensions determined by a manual segmentation of the photographed lesion based on the visible discoloration of the tissue were compared to automatic segmentations of the ARFI image using two different calculated thresholds. ARFI imaging accurately localized and sized the lesions within the myocardium. Differences in the maximum lateral and axial dimensions were statistically below 2 mm and 1 mm respectively for the two thresholding methods, with mean percent overlap of 68.7±5.21% and 66.3±8.4% for the two thresholds used. Conclusion ARFI imaging is capable of visualizing myocardial RFA lesion dimensions to within 2 mm in vitro. Visualizing lesions during transcatheter cardiac ablation procedures could improve the success of the treatment by imaging lesion line discontinuity and potentially reducing the required number of ablation lesions and procedure time.

Eyerly, Stephanie A.; Hsu, Stephen J.; Agashe, Shruti H.; Trahey, Gregg E.; Li, Yang; Wolf, Patrick D.

2009-01-01

311

Utilization of YouTube as a Tool to Assess Patient Perception Regarding Implanted Cardiac Devices  

PubMed Central

Background: The outreach of YouTube may have a dramatic role in the widespread dissemination of knowledge on implantable cardioverter devices (ICD). Aims: This study was designed to review and analyze the information available on YouTube pertaining to implantable cardiac devices such as implantable cardioverter defibrillators (ICDs) and pacemakers. Materials and Methods: YouTube was queried for the terms “ICD”, “Implantable Cardioverter Defibrillator”, and “Pacemaker”. The videos were reviewed and categorized as according to content; number of views and “likes” or “dislikes” was recorded by two separate observers. Results: Of the 55 videos reviewed, 18 of the videos were categorized as patient education, 12 were advertisements, 8 were intraoperative videos documenting the device implantation procedures, 7 of the videos were produced to document personal patient experiences, and 4 were categorized as documentation of a public event. 3 were intended to educate health care workers. The remaining 3 were intended to raise public awareness about sudden cardiac death. The videos portraying intraoperative procedures generated the most “likes” or “dislikes” per view. Conclusion: While YouTube provides a logical platform for delivery of health information, the information on this platform is not regulated. Initiative by reputed authorities and posting accurate information in such platform can be a great aid in public education regarding device therapy.

Hayes, Kevin; Mainali, Prajeena; Deshmukh, Abhishek; Pant, Sadip; Badheka, Apurva O; Paydak, Hakan

2014-01-01

312

Does the presence or absence of sonographically identified cardiac activity predict resuscitation outcomes of cardiac arrest patients?  

Microsoft Academic Search

This study evaluated the ability of cardiac sonography performed by emergency physicians to predict resuscitation outcomes of cardiac arrest patients. A convenience sample of cardiac arrest patients prospectively underwent bedside cardiac sonography at 4 emergency medicine residency–affiliated EDs as part of the Sonography Outcomes Assessment Program. Cardiac arrest patients in pulseless electrical activity (PEA) and asystole underwent transthoracic cardiac ultrasound

Philip Salen; Larry Melniker; Carolyn Chooljian; John S. Rose; Janet Alteveer; James Reed; Michael Heller

2005-01-01

313

An echocardiographic assessment of cardiac morphology and common ECG findings in teenage professional soccer players: reference ranges for use in screening  

Microsoft Academic Search

OBJECTIVETo assess physiological cardiac adaptation in adolescent professional soccer players.SUBJECTS AND DESIGNOver a 32 month period 172 teenage soccer players were screened by echocardiography and ECG at a tertiary referral cardiothoracic centre. They were from six professional soccer teams in the north west of England, competing in the English Football League. One was excluded because of an atrial septal defect.

J D Somauroo; J R Pyatt; M Jackson; R A Perry; D R Ramsdale

2001-01-01

314

A new method of assessing cardiac autonomic function and its comparison with spectral analysis and coefficient of variation of R–R interval  

Microsoft Academic Search

A new non-linear method of assessing cardiac autonomic function was examined in a pharmacological experiment in ten healthy volunteers. The R–R interval data obtained under a control condition and in autonomic blockade by atropine and by propranolol were analyzed by each of the new methods employing Lorenz plot, spectral analysis and the coefficient of variation. With our method we derived

Motomi Toichi; Takeshi Sugiura; Toshiya Murai; Akira Sengoku

1997-01-01

315

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.

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

316

Cardiac and neurological assessment of normothermia\\/warm blood cardioplegia vs hypothermia\\/cold crystalloid cardioplegia in pediatric cardiac surgery: insight from a prospective randomized trial  

Microsoft Academic Search

Objective: Although normothermia and warm blood cardioplegia are widely used in adults, cold crystalloids and hypothermia remain routinely used in pediatric cardiac surgery. The superiority of either technique in both brain and myocardial protection remains controversial. We designed a prospective randomized study to compare both approaches in terms of early myocardial protection and late neurodevelopmental status. Methods: From 2004 to

Alain J. Poncelet; Mathieu van Steenberghe; Stéphane Moniotte; Thierry Detaille; Christophe Beauloye; Luc Bertrand; Marie-Cécile Nassogne; Jean E. Rubay

317

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.

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

2014-01-01

318

Devices used in cardiac arrest.  

PubMed

Even the best conventional manual cardiopulmonary resuscitation (CPR) is highly inefficient, producing only a fraction of normal cardiac output. Over the past several decades, many therapeutic devices have been designed to improve on conventional CPR during cardiac arrest and increase the probability of survival. This article reviews several adjuncts and mechanical alternatives to conventional CPR for use during cardiac arrest. Recent clinical studies comparing conventional resuscitation techniques with the use of devices during cardiac arrest are reviewed, with a focus on clinical implications and directions for future research. PMID:22107983

Brooks, Steven C; Toma, Alina; Hsu, Jonathan

2012-02-01

319

Four-dimensional computed tomography: a method of assessing right ventricular outflow tract and pulmonary artery deformations throughout the cardiac cycle  

Microsoft Academic Search

Objective  To characterise 3D deformations of the right ventricular outflow tract (RVOT)\\/ pulmonary arteries (PAs) during the cardiac\\u000a cycle and estimate the errors of conventional 2D assessments.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Contrast-enhanced, ECG-gated cardiovascular computed tomography (CT) findings were retrospectively analysed from 12 patients.\\u000a The acquisition of 3D images over 10 phases of the cardiac cycle created a four-dimensional CT (4DCT) dataset. The datasets\\u000a were

Silvia Schievano; Claudio Capelli; Carol Young; Philipp Lurz; Johannes Nordmeyer; Catherine Owens; Philipp Bonhoeffer; Andrew M. Taylor

2011-01-01

320

Contribution to the biological assessment of orthodontic acrylic materials. Measurement of their residual monomer output and cytotoxicity.  

PubMed

The acrylic materials used in orthodontics for the fabrication of removable appliances are subjected in the oral cavity to processes of change which influence their physical, mechanical and biological properties. It is therefore essential that every newly developed material must be judged in terms of its clinical value. In the present study, 2 orthodontic cold-cure acrylics, Orthocryl and Forestacryl, and 4 orthodontic photocure acrylics, Triad, Wil-O-Dont, Odontolux and Lux-A-Tech, were investigated and compared with 2 prosthetic acrylic materials: the cold-cure acrylic Palapress and the hot-cure acrylic Paladon. The quantity of residual monomers from methyl methacrylate (MAA) or urethane dimethacrylate (UDMA) eluted from the sample in a given time after the processing was estimated by high pressure liquid chromatography (HPLC). The cytotoxic properties of the materials were examined by Mosmann's proliferation-inhibition test with an established culture of fibroblasts (= MTT test). The hot-cure acrylic Paladon produced by far the smallest amount of eluted residual monomer and the least growth inhibition in the MTT test. The prosthetic cold-cure acrylic Palapress achieved significantly better results than the orthodontic cold-cure materials Orthocryl and Forestacryl. The photocure acrylics released less UDMA than did the cold-cure acrylics MMA. In the cell culture test, all the orthodontic materials examined were assessed as "slightly cytotoxic"; the prosthetic acrylics were graded under ISO-standard 10993-5 as "noncytotoxic". After soaking the plastic material in water for 3 days its cytotoxic properties, as exemplified by the cold-cure acrylic Forestacryl and the photocure acrylic Triad, were reduced, and during the following investigation no more inhibition of growth was observed. It was possible to confirm with the tests used that, for Triad, it is necessary to carefully remove the oxygen-inhibition layer of the photocure acrylic in order to improve the biological properties. The influence of the plastic material on fibroblast cultures was assessed, among other methods, by the quantity of residual monomers liberated. These were significantly reduced after soaking the manufactured substance in water for 3 days. Careful laboratory treatment of the photocure acrylics is necessary in order to improve their biological properties. PMID:10961050

Rose, E C; Bumann, J; Jonas, I E; Kappert, H F

2000-01-01

321

Invasive hemodynamic assessment in heart failure.  

PubMed

Routine cardiac catheterization provides data on left heart, right heart, systemic and pulmonary arterial pressures, vascular resistances, cardiac output, and ejection fraction. These data are often then applied as markers of cardiac preload, afterload, and global function, although each of these parameters reflects more complex interactions between the heart and its internal and external loads. This article reviews more specific gold standard assessments of ventricular and arterial properties, and how these relate to the parameters reported and utilized in practice, and then discusses the re-emerging importance of invasive hemodynamics in the assessment and management of heart failure. PMID:21459248

Borlaug, Barry A; Kass, David A

2011-05-01

322

Interday Reliability of Peak Muscular Power Outputs on an Isotonic Dynamometer and Assessment of Active Trunk Control Using the Chop and Lift Tests  

PubMed Central

Abstract Context: Assessment techniques used to measure functional tasks involving active trunk control are restricted to linear movements that lack the explosive movements and dynamic tasks associated with activities of daily living and sport. Reliable clinical methods used to assess the diagonal and ballistic movements about the trunk are lacking. Objective: To assess the interday reliability of peak muscular power outputs while participants performed diagonal chop and lift tests and maintained a stable trunk. Design: Controlled laboratory study. Setting: University research laboratory. Patients or Other Participants: Eighteen healthy individuals (10 men and 8 women; age ?=? 32 ± 11 years, height ?=? 168 ± 12 cm, mass ?=? 80 ± 19 kg) from the general population participated. Intervention(s): Participants performed 2 power tests (chop, lift) using an isotonic dynamometer and 3 endurance tests (Biering-Sørensen, side-plank left, side-plank right) to assess active trunk control. Testing was performed on 3 different days separated by at least 1 week. Reliability was compared between days 1 and 2 and between days 2 and 3. Correlations between the power and endurance tests were evaluated to determine the degree of similarity. Main Outcome Measure(s): Peak muscular power outputs (watts) derived from a 1-repetition maximum protocol for the chop and lift tests were collected for both the right and left sides. Results: Intraclass correlation coefficients for peak muscular power were highly reliable for the chop (range, 0.87–0.98), lift (range, 0.83–0.96), and endurance (range, 0.80–0.98) tests between test sessions. The correlations between the power assessments and the Biering-Sørensen test (r range, ?0.008 to 0.017) were low. The side-plank tests were moderately correlated with the chop (r range, 0.528–0.590) and the lift (r range, 0.359–0.467) tests. Conclusions: The diagonal chop and lift power protocol generated reliable data and appears to be a dynamic test that simulates functional tasks, which require dynamic trunk control.

Palmer, Thomas G.; Uhl, Timothy L.

2011-01-01

323

Cardiac Assessment Risk Evaluation (Care Study) of African American College Women  

ERIC Educational Resources Information Center

Objective: To identify physiological and psychosocial variables of young African American women that may serve as a risk factor for heart disease and to assess their health promotion programme preferences. Method: A descriptive design was used to assess the cardiovascular risk factors of 100 African American women ages 18 to 40 years, enrolled in…

Brown, Sandra C.; Geiselman, Paula J.; Copeland, Amy L.; Gordon, Carol; Dudley, Mary; Manogin, Toni; Backstedt, Carol; Pourciau, Cathi; Ghebretatios, Ghenet

2005-01-01

324

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

PubMed

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

325

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.

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

2013-01-01

326

A Novel Miniaturized Multimodal Bioreactor for Continuous In Situ Assessment of Bioartificial Cardiac Tissue During Stimulation and Maturation  

PubMed Central

Stem cell-based cardiac tissue engineering is a promising approach for regenerative therapy of the injured heart. At present, the small number of stem cell-derived cardiomyocytes that can be obtained using current culture and enrichment techniques represents one of the key limitations for the development of functional bioartificial cardiac tissue (BCT). We have addressed this problem by construction of a novel bioreactor with functional features of larger systems that enables the generation and in situ monitoring of miniaturized BCTs. BCTs were generated from rat cardiomyocytes to demonstrate advantages and usefulness of the bioreactor. Tissues showed spontaneous, synchronized contractions with cell orientation along the axis of strain. Cyclic stretch induced cardiomyocyte hypertrophy, demonstrated by a shift of myosin heavy chain expression from the alpha to beta isoform, together with elevated levels of atrial natriuretic factor. Stretch led to a moderate increase in systolic force (1.42?±?0.09?mN vs. 0.96?±?0.09?mN in controls), with significantly higher forces observed after ?-adrenergic stimulation with noradrenalin (2.54?±?0.11?mN). Combined mechanical and ?-adrenergic stimulation had no synergistic effect. This study demonstrates for the first time that mechanical stimulation and direct real-time contraction force measurement can be combined into a single multimodal bioreactor system, including electrical stimulation of excitable tissue, perfusion of the culture chamber, and the possibility of (fluorescence) microscopic assessment during continuous cultivation. Thus, this bioreactor represents a valuable tool for monitoring tissue development and, ultimately, the optimization of stem cell-based tissue replacement strategies in regenerative medicine.

Kensah, George; Viering, Jorg; Schumann, Henning; Dahlmann, Julia; Meyer, Heiko; Skvorc, David; Bar, Antonia; Akhyari, Payam; Heisterkamp, Alexander; Haverich, Axel; Martin, Ulrich

2011-01-01

327

78 FR 36787 - Rechanneling the Current Cardiac Risk Paradigm: Arrhythmia Risk Assessment During Drug...  

Federal Register 2010, 2011, 2012, 2013

...TdP) risk and explore the parameters for an appropriate, strong, nonclinical proarrthymia screening method as an alternative...assessing TdP risk and explore the parameters for an appropriate, strong, nonclinical proarrthymia screening method as an...

2013-06-19

328

Assessment of the role of the renin-angiotensin system in cardiac contractility utilizing the renin inhibitor remikiren.  

PubMed Central

1. The role of the renin-angiotensin system in the regulation of myocardial contractility is still debated. In order to investigate whether renin inhibition affects myocardial contractility and whether this action depends on intracardiac rather than circulating angiotensin II, the regional myocardial effects of systemic (i.v.) and intracoronary (i.c.) infusions of the renin inhibitor remikiren, were compared and related to the effects on systemic haemodynamics and circulating angiotensin II in open-chest anaesthetized pigs (25-30 kg). The specificity of the remikiren-induced effects was tested (1) by studying its i.c. effects after administration of the AT1-receptor antagonist L-158,809 and (2) by measuring its effects on contractile force of porcine isolated cardiac trabeculae. 2. Consecutive 10 min i.v. infusions of remikiren were given at 2, 5, 10 and 20 mg min-1. Mean arterial pressure (MAP), cardiac output (CO), heart rate (HR), systemic vascular resistance (SVR), myocardial oxygen consumption (MVO2) and left ventricular (LV) dP/dtmax were not affected by remikiren at 2 and 5 mg min-1, and were lowered at higher doses. At the highest dose, MAP decreased by 48%, CO by 13%, HR by 14%, SVR by 40%, MVO2 by 28% and LV dp/dtmax by 52% (mean values; P < 0.05 for difference from baseline, n = 5). The decrease in MVO2 was accompanied by a decrease in myocardial work (MAP x CO), but the larger decline in work (55% vs. 28%; P < 0.05) implies a reduced myocardial efficiency ((MAP x CO)/MVO2). 3. Consecutive 10 min i.c. infusions of remikiren were given at 0.2, 0.5, 1, 2, 5 and 10 mg min-1. MAP, CO, MVO2 and LV dP/dtmax were not affected by remikiren at 0.2, 0.5 and 1 mg min-1, and were reduced at higher doses. At the highest dose, MAP decreased by 31%, CO by 26%, MVO2 by 46% and LV dP/dtmax by 43% (mean values; P < 0.05 for difference from baseline, n = 6). HR and SVR did not change at any dose. 4. Thirty minutes after a 10 min i.v. infusion of the AT1 receptor antagonist, L-158,809 at 1 mg min-1, consecutive 10 min i.c. infusions (n = 5) of remikiren at 2, 5 and 10 mg min-1 no longer affected CO and MVO2, and decreased LV dP/dtmax by maximally 27% (P < 0.05) and MAP by 14% (P < 0.05), which was less than without AT1-receptor blockade (P < 0.05). HR and SVR remained unaffected. 5. Plasma renin activity and angiotensin I and II were reduced to levels at or below the detection limit at doses of remikiren that were not high enough to affect systemic haemodynamics or regional myocardial function, both after i.v. and i.c. infusion. 6. Remikiren (10(-10) to 10(-4) M) did not affect contractile force of porcine isolated cardiac trabeculae precontracted with noradrenaline. In trabeculae that were not precontracted no decrease in baseline contractility was observed with remikiren in concentrations up to 10(-5) M, whereas at 10(-4) M baseline contractility decreased by 19% (P < 0.05). 7. Results show that with remikiren i.v., at the doses we used, blood pressure was lowered primarily by vasodilation and with remikiren i.c. by cardiac depression. The blood levels of remikiren required for its vasodilator action are lower than the levels affecting cardiac contractile function. A decrease in circulating angiotensin II does not appear to be the sole explanation for these haemodynamic responses. Data support the contention that myocardial contractility is increased by renin-dependent angiotensin II formation in the heart.

van Kats, J. P.; Sassen, L. M.; Danser, A. H.; Polak, M. P.; Soei, L. K.; Derkx, F. H.; Schalekamp, M. A.; Verdouw, P. D.

1996-01-01

329

Simultaneous assessment of cardiac perfusion and function using 5-dimensional imaging with Tc99m teboroxime  

Microsoft Academic Search

Background  Dynamic single photon emission computed tomography (SPECT) acquisition and reconstruction of early poststress technetium 99m\\u000a teboroxime washout images has been shown to be useful in the detection of coronary disease. Assessment of poststress regional\\u000a wall motion may offer additional use in assessing coronary disease. Our goal was to investigate the feasibility of simultaneously\\u000a imaging myocardial ischemia and transient poststress akinesis

Bing Feng; P. Hendrik Pretorius; Troy H. Farncombe; Seth T. Dahlberg; Manoj V. Narayanan; Miles N. Wernick; Anna M. Celler; Jeffrey A. Leppo; Michael A. King

2006-01-01

330

Assessment of parental decision-making in neonatal cardiac research: a pilot study  

Microsoft Academic Search

ObjectiveTo assess parental permission for a neonate's research participation using the MacArthur competence assessment tool for clinical research (MacCAT-CR), specifically testing the components of understanding, appreciation, reasoning and choice.Study DesignQuantitative interviews using study-specific MacCAT-CR tools.HypothesisParents of critically ill newborns would produce comparable MacCAT-CR scores to healthy adult controls despite the emotional stress of an infant with critical heart disease or

Aruna T Nathan; K Sarah Hoehn; Richard F Ittenbach; J William Gaynor; Susan Nicolson; Gil Wernovsky; Robert M Nelson

2010-01-01

331

Assessment of regional aortic stiffness with cardiac magnetic resonance imaging in a healthy Asian population.  

PubMed

The aim of this study was to determine the normal values for aortic pulse wave velocity (PWV) and distensibility using cine and phase contrast cardiac magnetic resonance imaging (CMRI) in patients without cardiovascular risk factors. PWV and distensibility are indispensible predictors of global and regional cardiovascular risk. Regional heterogeneity in aortic stiffness plays an important role in the pathogenesis of cardiovascular disease. Contrary to global estimates of aortic PWV that are commonly measured with tonometry, CMRI has emerged as an important method for estimating regional PWV and distensibility. A total of 124 Korean patients, aged 20-79 years and free of cardiovascular risk factors, were categorized by age decade. Using cine and phase contrast sequences, the cross-sectional area for distensibility and average blood flow were measured at four aortic levels: the ascending, upper descending thoracic, lower thoracic and abdominal aorta. Regional PWV was determined in four aortic segments: proximal, descending thoracic, abdominal aorta and across the entire aorta. Distensibility at the four levels of the aorta from the ascending to distal (4.4 ± 2.5, 4.0 ± 1.6, 5.2 ± 1.9, and 3.3 ± 1.7 × 10(-3) mm/Hg, respectively) was higher in women (P < 0.001) and decreased with age. The regional PWV was highest in the descending thoracic aorta and increased with age. The present study is the first to show the heterogeneity in aortic PWV and distensibility, as well to provide normal values for these parameters using CMRI in an Asian sample. PMID:23504214

Kim, Eun Kyoung; Chang, Sung-A; Jang, Shin Yi; Kim, Yiseul; Kim, Sung Mok; Oh, Jae K; Choe, Yeon Hyeon; Kim, Duk-Kyung

2013-06-01

332

Prospective Echocardiographic Assessment of Cardiac Structure and Function in Chinese Persons Living With HIV.  

PubMed

Background.?Persons living with human immunodeficiency virus (HIV) are at increased risk of developing cardiovascular disease. Few studies have focused on echocardiographic abnormalities in this population. Methods.?China AIDS Clinical Trial 0810 is a prospective, multicenter cohort study of persons living with HIV (PLWH). We performed an echocardiography substudy of 325 PLWH. We examined the prevalence of left ventricular systolic dysfunction (LVSD), diastolic dysfunction (DD), pulmonary arterial hypertension (PAH), and increased left ventricular mass (ILVM) in antiretroviral therapy (ART)-naive PLWH at baseline and week 48 after initiation of ART. Results.?Compared with age- and sex-matched healthy controls, PLWH had a higher prevalence of DD (16.5% vs 7.2%, P < .027) and a marginally significant higher prevalence of LVSD (7.3% vs 2.1%, P = .056). The increase in the prevalence of DD from baseline to week 48 in PLWH was marginally significant (P = .056). No significant difference was observed in the prevalence of LVSD, PAH, or ILVM at baseline and week 48 in PLWH. In logistic regression analysis of all participants, age was significantly associated with LVSD; HIV infection, age, and hypertension were associated with DD whereas HIV infection and hypertension were associated with ILVM at baseline. Logistic regression analysis of PLWH showed that only age was significantly associated with LVSD and DD. Conclusions.?The prevalence of echocardiographic abnormalities was significantly higher in ART-naive PLWH than in controls. HIV infection was significantly associated with cardiac abnormalities. No significant change in echocardiographic abnormalities was observed after 48 weeks of ART. Longer-term prospective studies are warranted. PMID:24569532

Luo, Ling; Zeng, Yong; Li, Taisheng; Lv, Wei; Wang, Huanling; Guo, Fuping; Han, Yang; Xie, Jing; Qiu, Zhifeng; Li, Yanling; Song, Xiaojing; Zhu, Ting; Zhang, Xiaoying; Li, Ling; Ye, Yicong; He, Yun; Lu, Hongzhou; Huang, Aiqiong; Tang, Xiaoping; Wang, Hui; Zhang, Tong; Gao, Guiju; Lei, Junkang; Wu, Xinhua; Sun, Yongtao; Bai, Jinsong; Li, Kunli

2014-05-01

333

Assessing Impacts of Climate Change on Biomass and Species Composition across Russia using a Dynamic Vegetation Model and IPCC Climate Output  

NASA Astrophysics Data System (ADS)

The Northern Hemisphere's boreal forests and, in particular, the Siberian boreal forest zone, may have a particularly strong effect on the Earth's climate through mechanisms involving changes in the regional surface albedo. Warmer climate has been implicated in the conversion of Russia's Siberian Larch forests to Dark-Conifer Forests of Spruce and Fir implying a potential positive feedback cycle: a warmer climate can accelerate the natural succession from Larch to Dark-Conifer forest; the resultant albedo change then can promote additional climate warming. This climate/cover feedback motivates development of dynamic models simulating the composition of Russian forest. Utilization of the individual based forest growth model, FAREAST, with climate station data provided by the National Climate Data Center (NCDC) for 2083 Russian stations allowed us to generate baseline biomass values (tCha-1) from year zero to mature forest. The model biomass (tCha-1) was previously validated using independent forest inventory data from across the Russian region. The FAREAST model output represents the average of 200 simulated plots per location for climatic conditions reported for the corresponding station. IPCC climate output data from NCAR's Community Climate System Model 3.0 (CCSM) SRES climate change scenarios, A1B and B1, were used to evaluate detailed changes in biomass (tCha-1) and species composition of forests across Russia in response to warming for stands of various ages. These results are used to identify the location, age and species composition of forests which are vulnerable to climate change. Assessing the forest vulnerability in congruence with the age and species distribution is a powerful tool in understanding forest response to climate change in addition to the forests role in climate/cover feedback associated with albedo change.

Shuman, J.; Shugart, H.

2009-04-01

334

Role of cardiac catheterization and percutaneous coronary intervention in the preoperative assessment and management of patients before orthotopic liver transplantation.  

PubMed

Limited data regarding the optimal risk assessment strategy for evaluating candidates for orthotopic liver transplantation (OLT) exist. Our center has adopted a policy of performing cardiac catheterization (CATH) in patients with predefined risk factors, and this is followed by percutaneous coronary intervention (PCI) when it is indicated, even in the presence of negative stress test findings. The aim of this single-center, retrospective study of all patients who underwent OLT between 2000 and 2010 was to assess the effect of our policy on cardiovascular (CV) complications and survival rates after OLT. Data, including 1-year all-cause and CV mortality, postoperative myocardial infarctions (MIs), and frequencies of CATH and PCI, were abstracted. The study was divided into 3 subperiods to reflect the changes in policy over this period: (A) 2000-2004, (B) 2005-2008, and (C) 2009-2010. One thousand two hundred twenty-one patients underwent OLT between 2000 and 2010. The rate of catheterization increased during the 3 time periods (P?

Maddur, Haripriya; Bourdillon, Patrick D; Liangpunsakul, Suthat; Joseph Tector, A; Fridell, Jonathan A; Ghabril, Marwan; Lacerda, Marco A; Bourdillon, Charlotte; Shen, Changyu; Kwo, Paul Y

2014-06-01

335

Cardiac magnetic resonance imaging myocardial perfusion reserve index assessment in women with microvascular coronary dysfunction and reference controls  

PubMed Central

Objective We sought to comparatively assess cardiac magnetic resonance imaging (CMRI) myocardial perfusion reserve index (MPRI) in women with confirmed microvascular coronary dysfunction (MCD) cases and reference control women. Background Women with signs or symptoms of myocardial ischemia in the absence of obstructive coronary artery disease (CAD) frequently have MCD which carries an adverse prognosis. Diagnosis involves invasive coronary reactivity testing (CRT). Adenosine CMRI is a non-invasive test that may be useful for the detection of MCD. Methods Fifty-three women with MCD confirmed by CRT and 12 age- and estrogen-use matched reference controls underwent adenosine CMRI. CMRI was assessed for MPRI, calculated using the ratio of myocardial blood flow at hyperemia/rest for the whole myocardium and separately for the 16 segments as defined by the American Heart Association. Statistical analysis was performed using repeated measures ANOVA models. Results Compared to reference controls, MCD cases had lower MPRI values globally and in subendocardial and subepicardial regions (1.63±0.39 vs. 1.98±0.38, P=0.007, 1.51±0.35 vs. 1.84±0.34, P=0.0045, 1.68±0.38 vs. 2.04±0.41, P=0.005, respectively). A perfusion gradient across the myocardium with lower MPRI in the subendocardium compared to the subepicardium was observed for both groups. Conclusions Women with MCD have lower MPRI measured by perfusion CMRI compared to reference controls. CMRI may be a useful diagnostic modality for MCD. Prospective validation of a diagnostic threshold for MPRI in patients with MCD is needed.

Thomson, Louise E. J.; Goykhman, Pavel; Agarwal, Megha; Mehta, Puja K.; Sedlak, Tara; Li, Ning; Gill, Edward; Samuels, Bruce; Azabal, Babak; Kar, Saibal; Kothawade, Kamlesh; Minissian, Margo; Slomka, Piotr; Berman, Daniel S.; Bairey Merz, C. Noel

2013-01-01

336

Assessment of cerebellar pulsation in dogs with and without Chiari-like malformation and syringomyelia using cardiac-gated cine magnetic resonance imaging.  

PubMed

Canine Chiari-like malformation (CM) is characterised by herniation of part of the cerebellum through the foramen magnum. In humans with Chiari type I malformation (CM-I), abnormal pulsation of the cerebellum during the cardiac cycle has been documented and is pivotal to theories for the pathogenesis of syringomyelia (SM). In this retrospective study, cardiac-gated cine balanced fast field echo (bFEE) magnetic resonance imaging (MRI) was used to assess pulsation of the brain in dogs and to objectively measure the degree of cerebellar pulsation with the neck in a flexed position. Overall, 17 Cavalier King Charles Spaniels (CKCS) with CM, including eight with SM and nine without SM, were compared with six small breed control dogs. Linear regions of interest were generated for the length of cerebellar herniation from each phase of the cardiac cycle and the degree of cerebellar pulsation was subsequently calculated. Age, bodyweight and angle of neck flexion were also compared. CKCS with CM and SM had significantly greater pulsation of the cerebellum than control dogs (P=0.003) and CKCS with CM only (P=0.031). There was no significant difference in age, bodyweight and angle of neck flexion between the three groups. Cardiac-gated cine bFEE MRI permitted the dynamic visualisation of cerebellar pulsation in dogs. These findings support the current theories regarding the pathogenesis of SM secondary to CM and further highlight the similarities between canine CM and human CM-I. PMID:23770398

Driver, C J; Watts, V; Bunck, A C; Van Ham, L M; Volk, H A

2013-10-01

337

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

338

Cardiac device-related invasive aspergilloma assessed by live/real time three-dimensional transthoracic echocardiography.  

PubMed

Cardiac device-related infection caused by Aspergillus species is a rare finding associated with high mortality. Prompt recognition and treatment is imperative, but difficult as blood cultures are often negative and diagnosis requires a high index of suspicion. Live/real time three-dimensional transthoracic echocardiography (3DTTE) provides incremental knowledge in the characterization of valvular vegetations. Here, we provide a detailed description of an invasive cardiac device-related infection caused by Aspergillus fumigatus using 3DTTE. Findings described here highlight the role for 3DTTE in the prompt diagnosis of invasive cardiac Aspergillus infections as well as surgical planning in such cases. PMID:23662919

Clark, Donald; Ahmed, Mustafa I; Sungur, Aylin; Kemalo?luöz, Tu?ba; Mehta, Kruti Jayesh; Diddi, Hari Prakash; Tandon, Rohit; Reddy, Vishnu V; Nanda, Navin C; McGiffin, David C

2013-07-01

339

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

340

Monte Carlo simulations to assess differentiation between defects in cardiac SPECT  

NASA Astrophysics Data System (ADS)

Differentiating between various types of lesions in nuclear cardiology is a challenge. This work assesses the level of differentiation achievable between various low contrast lesions, as encountered in nuclear cardiology. The parameters investigated are defect extend, defect thickness and perfusion reduction of the defect. The images have been obtained through Monte Carlo Simulations with the program SIMIND. Results show that acceptable size resolution is obtained for defects with an extend over 25×25mm. When thickness and perfusion reduction are both unknown, the imaging results are confounding. In this work, thickness and perfusion reduction cannot be differentiated. If one of the variables is known (thickness or perfusion reduction), imaging results can differentiate between the other unknown variable.

Chrysanthou-Baustert, I.; Parpottas, Y.; Demetriadou, O.; Christofides, S.; Yiannakkaras, Ch; Kaolis, D.; Wasilewska-Radwanska, M.

2011-09-01

341

Use of equilibrium (gated) radionuclide ventriculography to quantitate left ventricular output in patients with and without left-sided valvular regurgitation.  

PubMed

We examined the accuracy with which left ventricular output can be estimated by equilibrium radionuclide ventriculography. After red blood cells were labeled in vivo, we measured left ventricular end-diastolic and end-systolic count rates and the count rate in 5 ml of the patient's blood. After estimating the average ratio of counting efficiency for the left ventricle to counting efficiency for the blood sample (Elv/Es) in six patients, we calculated left ventricular output in 26 other patients as (left ventricular activity ejected per minute divided by activity per liter of blood) divided by the previously estimated Elv/Es. Radionuclide left ventricular output closely approximated Fick cardiac output (r = 0.94) in patients without mitral or aortic regurgitation and exceeded Fick cardiac output in all patients with valvular regurgitation. Regurgitant fraction, calculated as the difference between the radionuclide and Fick outputs divided by the radionuclide output, correlated with the severity of of regurgitation as assessed angiographically. The equilibrium radionuclide ventriculogram is an excellent means for noninvasive estimation of left ventricular output. PMID:6266693

Konstam, M A; Wynne, J; Holman, B L; Brown, E J; Neill, J M; Kozlowski, J

1981-09-01

342

Assessing Cardiac Injury in Mice with Dual Energy-microCT, 4D-microCT and microSPECT Imaging Following Partial-Heart Irradiation  

PubMed Central

Purpose To develop a mouse model of cardiac injury following partial-heart irradiation (PHI) and test whether DE-microCT and 4D-microCT can be used to assess cardiac injury after PHI to complement myocardial perfusion imaging using microSPECT. Methods and Materials To study cardiac injury from tangent field irradiation in mice, we used a small-field biological irradiator to deliver a single dose of 12 Gy x-rays to approximately one-third of the left ventricle (LV) of Tie2Cre; p53FL/+ and Tie2Cre; p53FL/? mice, where one or both alleles of p53 are deleted in endothelial cells. Four and 8 weeks after irradiation, mice were injected with gold and iodinated nanoparticle-based contrast agents, and imaged with DE-microCT and 4D-microCT to evaluate myocardial vascular permeability and cardiac function, respectively. Additionally, the same mice were imaged with microSPECT to assess myocardial perfusion. Results After PHI with tangent fields, DE-microCT scans showed a time-dependent increase in accumulation of gold nanoparticles (AuNp) in the myocardium of Tie2Cre; p53FL/? mice. In Tie2Cre; p53FL/? mice, extravasation of AuNp was observed within the irradiated LV, whereas in the myocardium of Tie2Cre; p53FL/+ mice, AuNp were restricted to blood vessels. In addition, data from DE-microCT and microSPECT showed a linear correlation (R2=0.97) between the fraction of the LV that accumulated AuNp and the fraction of LV with a perfusion defect. Furthermore, 4D-microCT scans demonstrated that PHI caused Tie2Cre; p53FL/? mice to develop a markedly decreased ejection fraction, and higher end-diastolic and end-systolic volumes, which were associated with compensatory cardiac hypertrophy of the heart that was not irradiated. Conclusions Our results show that DE-microCT and 4D-microCT with nanoparticle-based contrast agents are novel imaging approaches complementary to microSPECT to non-invasively assess the change in myocardial vascular permeability and cardiac function of mice that develop myocardial injury after PHI.

Lee, Chang-Lung; Min, Hooney; Befera, Nicholas; Clark, Darin; Qi, Yi; Das, Shiva; Johnson, G. Allan; Badea, Cristian T.; Kirsch, David G.

2014-01-01

343

Evaluation of Technologies for Identifying Acute Cardiac Ischemia in Emergency Departments. Evidence Report/Technology Assessment Number 26.  

National Technical Information Service (NTIS)

This report evaluates the accuracy of technologies for diagnosing acute cardiac ischemia (ACI) in Emergency Departments and their clinical impact when used in ED setting. The diagnostic technologies examined include the following: electocardiography (preh...

J. Lau

2001-01-01

344

Cardiac vectors in the healthy human fetus: developmental changes assessed by magnetocardiography and realistic approximations of the volume conductor  

PubMed Central

This study sought to characterize the developmental changes of three measures used to describe the morphology of the fetal cardiac vector: QRS peak-amplitude, QRS duration and QRS time-amplitude integral. To achieve this objective, we rely on a recently developed methodology for fetal cardiac vector estimation, using multichannel fetal magnetocardiographic (fMCG) recordings and realistic approximations of the volume conductors obtained from free-hand ultrasound imaging. Fetal magnetocardiographic recordings and 3D ultrasound images were obtained from 23 healthy, uncomplicated pregnancies for a total of 77 recordings performed at gestational ages between 22 weeks and 37 weeks. We report the developmental changes of the cardiac vector parameters with respect to gestational age and estimated fetal weight, as well as their dependence on the estimated ventricular mass derived from cardiac dimensions measured with M-mode ultrasound. The normative values can be used along with the cardiac time intervals reported by previous fMCG studies to assist future clinical studies investigating conditions that affect fetal cardiac function.

Tao, R; Popescu, EA; Drake, WB; Popescu, M

2014-01-01

345

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

346

7 Tesla (T) human cardiovascular magnetic resonance imaging using FLASH and SSFP to assess cardiac function: validation against 1.5 T and 3 T  

PubMed Central

We report the first comparison of cardiovascular magnetic resonance imaging (CMR) at 1.5 T, 3 T and 7 T field strengths using steady state free precession (SSFP) and fast low angle shot (FLASH) cine sequences. Cardiac volumes and mass measurements were assessed for feasibility, reproducibility and validity at each given field strength using FLASH and SSFP sequences. Ten healthy volunteers underwent retrospectively electrocardiogram (ECG) gated CMR at 1.5 T, 3 T and 7 T using FLASH and SSFP sequences. B1 and B0 shimming and frequency scouts were used to optimise image quality. Cardiac volume and mass measurements were not significantly affected by field strength when using the same imaging sequence (P > 0.05 for all parameters at 1.5 T, 3 T and 7 T). SSFP imaging returned larger end diastolic and end systolic volumes and smaller left ventricular masses than FLASH imaging at 7 T, and at the lower field strengths (P < 0.05 for each parameter). However, univariate general linear model analysis with fixed effects for sequence and field strengths found an interaction between imaging sequence and field strength (P = 0.03), with a smaller difference in volumes and mass measurements between SSFP and FLASH imaging at 7 T than 1.5 T and 3 T. SSFP and FLASH cine imaging at 7 T is technically feasible and provides valid assessment of cardiac volumes and mass compared with CMR imaging at 1.5 T and 3 T field strengths.

Suttie, J. J.; DelaBarre, L.; Pitcher, A.; van de Moortele, P. F.; Dass, S.; Snyder, C. J.; Francis, J. M.; Metzger, G. J.; Weale, P.; Ugurbil, K.; Neubauer, S.; Robson, M.; Vaughan, T.

2012-01-01

347

Naturally occurring cardiac glycosides.  

PubMed

Cardiac glycoside poisoning from the ingestion of plants, particularly of oleanders, occurs with reasonable frequency in tropical and subtropical areas. We have assessed a variety of plant specimens for their cardiac glycoside content by means of radioimmunoassays with antibodies that differ in their specificity for cardiac glycosides. Significant amounts of immunoreactive cardiac glycoside were found to be present in the ornamental shrubs: yellow oleander (Thevetia peruviana); oleander (Nerium oleander); wintersweet (Carissa spectabilis); bushman's poison (Carissa acokanthera); sea-mango (Cerbera manghas); and frangipani (Plumeria rubra); and in the milkweeds: redheaded cotton-bush (Asclepias curassavica); balloon cotton (Asclepias fruiticosa); king's crown (Calotropis procera); and rubber vine (Cryptostegia grandifolia). The venom gland of the cane toad (Bufo marinus) also contained large quantities of cardiac glycosides. The competitive immunoassay method permits the rapid screening of specimens that are suspected to contain cardiac glycosides. Awareness of the existence of these plant and animal toxins and their dangers allows them to be avoided and poisoning prevented. The method is also useful for the confirmation of the presence of cardiac glycosides in serum in cases of poisoning. PMID:3086679

Radford, D J; Gillies, A D; Hinds, J A; Duffy, P

1986-05-12

348

Cardiac Effect of Thyrotoxicosis in Acromegaly  

Microsoft Academic Search

Cardiac structure and function are affected both by acromegaly and hyperthyroidism. Whereas the former is mainly characterized by ven- tricular hypertrophy as well as diastolic and systolic impairment, the latter frequently leads to increased heart rate and enhancement of contractility and cardiac output. To further investigate this issue, we designed this two-arm study. In the first cross-sectional study, we compared

PAOLO MARZULLO; ALBERTO CUOCOLO; DIEGO FERONE; ROSARIO PIVONELLO; MARCO SALVATORE; GAETANO LOMBARDI; ANNAMARIA COLAO

349

The 'all comer' Coroflex Please drug-eluting stent registry in Europe and Asia - An overall and transcontinental assessment of the 10-month major adverse cardiac events  

PubMed Central

Background Randomized trials assess the potential of a medical device in well defined indications while “all comer studies” reveal the device performance in the real clinical environment. Aims This ‘all comers’ registry assessed the 10-month outcome of the Coroflex® Please drug-eluting stent in Europe and Asia by clinically driven major adverse cardiac events. Methods The Coroflex® Please Registry was an international, prospective, multicenter registry enrolling patients with symptomatic ischemic heart disease. The primary endpoint was clinically driven target lesion revascularization (TLR) at 9 months. Secondary endpoints were technical success, in-hospital outcomes, definite stent thrombosis and major adverse cardiac events (death, myocardial infarction, or TLR) for subgroup analyses. Results Of the enrolled 1230 patients (63.6 ± 11.2 years, 33.9% diabetics), 339 (27.6%) had an acute coronary syndrome, 148 (12.1%) STEMI and 191 (15.6%) NSTEMI. After 10.5 ± 3.8 months (follow-up rate 92.8%), the target lesion revascularization rate (TLR) was 7.8% overall, 8.3% in STEMI, and 11.3% in NSTEMI patients. Total MACE was 11.1% and significantly higher in ACS with either diabetes mellitus (22.9%, p = 0.017) or age ?75 years (25.4%, p = 0.026). In European and Asian patients MI rates (5.2% vs 3.1%, p = 0.135) and cardiac death rates (1.6% vs 0.9%, p = 0.414) were similar. The MACE rate was higher in Europe (13.6% vs 4.7%, p < 0.001) driven by a six times higher TLR rate. Conclusions TLR and MACE occurred within the range of previously published data. The incidence of MI and cardiac death were not different between Europe and Asia. MACE were higher in Europe driven by target lesion revascularization.

Leschke, Matthias; Nhan, Vo Thanh; Waliszewski, Matthias; Palacios, Vicente; Horvath, Ivan; Ivanov, Vladimir A.; Tresukosol, Damras; Avraamides, Panicos; Schneider, Andre; Unverdorben, Martin

2012-01-01

350

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

351

Input-Output Analysis as a Tool in Assessing the Impacts of Climatic Variations on Regional Economies: with Prototype Applications to the Oklahoma Economy  

Microsoft Academic Search

Input-output analysis techniques are developed to relate climate impacts affecting specific economic sectors to overall economic impacts in a regional economy. The types of applied problems covered include: (1) Estimates of impacts from \\

William S. Cooter

1984-01-01

352

Urine output - decreased  

MedlinePLUS

Decreased urine output means that you produce less than 500 milliliters of urine in 24 hours. ... A large decrease in urine output may be a sign of a serious, or even life-threatening, condition. However, urine output can usually be restored ...

353

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

354

Echocardiogram versus cardiac magnetic resonance imaging for assessing systolic function of subaortic right ventricle in adults with complete transposition of great arteries and previous atrial switch operation.  

PubMed

In adults with congenital heart disease and a systemic right ventricle, subaortic ventricular systolic dysfunction is common. Echocardiographic assessment of systolic right ventricular (RV) function in these patients is important but challenging. The aim of the present study was to assess the reliability of conventional echocardiographic RV functional parameters to quantify the systolic performance of a subaortic right ventricle. We compared 56 contemporary echocardiograms and cardiac magnetic resonance studies in 37 adults, aged 26.9 ± 7.4 years, with complete transposition and a subaortic right ventricle. The fractional area change (FAC), lateral tricuspid annular plane systolic excursion, lateral RV systolic motion velocities by tissue Doppler, RV myocardial performance index, and the rate of systolic RV pressure increase (dp/dt) measured across the tricuspid regurgitant jet were assessed by echocardiography and correlated with the cardiac magnetic resonance-derived RV ejection fraction (EF). The mean RVEF was 48.0 ± 7.8%. FAC (r(2) = 0.206, p = 0.001) and dp/dt (r(2) = 0.173, p = 0.009) significantly correlated with RVEF, and the other nongeometric echocardiographic parameters failed to show a significant correlation with RVEF by linear regression analysis. FAC <33% and dp/dt <1,000 mm Hg/s identified a RVEF of <50% with a sensitivity of 77% and 69% and a specificity of 58% and 87%, respectively. In conclusion, in patients with a systemic right ventricle, routine nongeometric echocardiographic parameters of RV function correlated weakly with cardiac magnetic resonance-derived EF. RV FAC and the measurement of the rate of systolic RV pressure increase (dp/dt) should be preferentially used to assess systemic systolic function in adult patients with a subaortic right ventricle. PMID:23276471

Khattab, Kerstin; Schmidheiny, Pascal; Wustmann, Kerstin; Wahl, Andreas; Seiler, Christian; Schwerzmann, Markus

2013-03-15

355

The cardiac response to exercise in cirrhosis  

PubMed Central

BACKGROUND—Impaired exercise capacity and oxygen consumption are common in cirrhosis.?AIM—To explore the relationship between possible myocardial dysfunction and exercise tolerance in cirrhosis.?METHODS—Cardiac responses to exercise, using radionuclide angiography and graded upright cycle ergometry with oxygen consumption, were assessed before and after exercise in 39 cirrhotics patients and compared with 12 age and sex matched healthy volunteers. Baseline cardiac chamber dimensions and wall thickness, ejection fraction, and diastolic function were measured using two dimensional echocardiography is all subjects.?RESULTS—Baseline diastolic dysfunction with prolonged isovolumic relaxation times (p=0.02), left atrial enlargement, and left ventricular wall thickening were present in all cirrhotics (p=0.02), despite increased mean ejection fraction. With graded exercise, cirrhotics achieved 71 (4)% (p=0.03) (pre-ascitics) and 46 (3)% (p<0.001) (ascitics) of predicted work loads, respectively, without significant increases in ejection fraction. The smaller absolute and percentage increases in cardiac output (p=0.003) in the cirrhotics were associated with significantly reduced oxygen consumption (p=0.003) and anaerobic threshold (p<0.001), and correlated significantly with work and metabolic parameters.?CONCLUSIONS—Impaired exercise capacity in cirrhosis is associated with myocardial thickening and ventricular stiffness leading to decreased diastolic function, inotropic and chronotropic incompetence under conditions of stress, with metabolic consequences. This picture is compatible with the condition now known as cirrhotic cardiomyopathy.???Keywords: cirrhosis; exercise tolerance; myocardial function; oxygen consumption

Wong, F; Girgrah, N; Graba, J; Allidina, Y; Liu, P; Blendis, L

2001-01-01

356

Use of Negative Extrathoracic Pressure to Improve Hemodynamics After Cardiac Surgery  

Microsoft Academic Search

Background. Little attention is given to the mode of mechanical ventilation after cardiac surgery. Positive pressure ventilation with positive end-expiratory pres- sure (PEEP) has been shown to reduce cardiac output. We hypothesized that positive pressure ventilation with continual negative pressure applied to the chest through a cuirass would increase cardiac output in coronary artery bypass graft patients immediately after surgery.

Rakesh K. Chaturvedi; Arnold A. Zidulka; Peter Goldberg; Sameena Iqbal; Elham Rahme; Kevin Lachapelle

357

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

358

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

PubMed

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. PMID:24002232

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

2014-01-01

359

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.

2013-01-01

360

Incremental Value of Pharmacological Stress Cardiac Dual-Energy CT Over Coronary CT Angiography Alone for the Assessment of Coronary Artery Disease in a High-Risk Population.  

PubMed

OBJECTIVE. The purpose of this article is to prospectively determine the value of stress dual-energy CT (DECT) myocardial perfusion imaging to coronary CT angiography (CTA) for the assessment of coronary artery disease (CAD) in a high-risk population. SUBJECTS AND METHODS. We prospectively enrolled 29 consecutive patients who were referred for cardiac SPECT examinations for known or suspected CAD to also undergo pharmacologic stress cardiac DECT. In 25 patients, cardiac catheterization was available as the reference standard for morphologically significant stenosis. The performance of coronary CTA alone, DECT myocardial perfusion alone, and the combination of both was assessed by calculating sensitivity, specificity, and AUC values. RESULTS. For morphologically significant stenosis, coronary CTA alone and myocardial DECT assessment alone had 95% sensitivity and 50% specificity. The combined approach yielded 100% sensitivity and 33% specificity if either was positive and 90% sensitivity and 67% specificity if both were positive. The AUC value was highest (0.78) if both were positive. For hemodynamically significant lesions, coronary CTA alone had 91% sensitivity and 38% specificity, and DECT alone had 95% sensitivity and 75% specificity. The combined approach yielded 100% sensitivity and 38% specificity if either was positive and 86% sensitivity and 75% specificity if both were positive. AUC values were highest for DECT alone (0.85) and the "both positive" evaluation (0.80). CONCLUSION. The combined analysis of coronary CTA and DECT myocardial perfusion reduces the number of false-positives in a high-risk population for CAD and outperforms the purely anatomic test of coronary CTA alone for the detection of morphologically and hemodynamically significant CAD. PMID:24951230

De Cecco, Carlo Nicola; Harris, Brett S; Schoepf, U Joseph; Silverman, Justin R; McWhite, Cullen B; Krazinski, Aleksander W; Bayer, Richard R; Meinel, Felix G

2014-07-01

361

Assessment of Patient Satisfaction With Telephone and Mail Interventions Provided by a Clinical Pharmacy Cardiac Risk Reduction Service  

Microsoft Academic Search

OBJECTIVE: Kaiser Permanente of Colorado developed a population-based program, the Clinical Pharmacy Cardiac Risk Service (CPCRS), to help close the treatment gap for patients with coronary artery disease. CPCRS provides much of its care via telephone. The purpose of this study was to determine the level of satisfaction among patients in this unique service. METHODS: This was a cross-sectional survey

SUSAN L. HOLSCLAW; KARI L. OLSON; ROSEANNE HORNAK; ANNE M. DENHAM

362

Nonlinear analysis of heart rate variability to assess the reaction of ewe fetuses undergoing fetal cardiac surgery.  

PubMed

Fetal cardiac surgery (FCS) represents a challenging issue for the in utero treatment of congenital heart defects. However, FCS has still not gained the sufficient reliability for clinical practice due to an incompletely elucidated fetal stress response. For example, blood sampling can contribute to its onset, leading to fetoplacental unit dysfunction, one of the main causes of failure of the surgical procedure. In order to address this issue, the role of the autonomic control system during an experimental procedure of cardiac bypass on ewe fetuses was investigated by means of recurrence quantification analysis (RQA), a well-recognized method for the analysis of nonlinear systems. RQA was applied to time series extracted from fetal arterial pressure recordings before and after the cardiac bypass established by means of an extracorporeal circuit, including an axial blood pump, and taking advantage of the capability of the placenta to work as a natural oxygenator. Statistically significant correlations were found among RQA-based metrics and fetal blood gas data, suggesting the possibility to infer the clinical status of the fetus starting from its hemodynamic signals.This study shows the relevance of RQA as a complementary tool for the monitoring of the fetal status during cardiac bypass. PMID:22669589

Del Gaudio, Costantino; Carotti, Adriano; Grigioni, Mauro; Morbiducci, Umberto

2012-05-01

363

Bioimpedance Analysis Parameters and Epicardial Adipose Tissue Assessed by Cardiac Magnetic Resonance Imaging in Patients With Heart Failure  

Microsoft Academic Search

There is increasing evidence that body composition should be considered as a systemic marker of disease severity in congestive heart failure (CHF). Prior studies established bioelectrical impedance analysis (BIA) as an objective indicator of body composition. Epicardial adipose tissue (EAT) quantified by cardiac magnetic resonance (CMR) is the visceral fat around the heart secreting various bioactive molecules. Our purpose was

Christina Doesch; Tim Suselbeck; Hans Leweling; Stephan Fluechter; Dariush Haghi; Stefan O. Schoenberg; Martin Borggrefe; Theano Papavassiliu

2010-01-01

364

Fatality Assessment and Control Evaluation (FACE) Report: Fire Fighter Suffers Cardiac Death After Responding to a Structure Fire - New York.  

National Technical Information Service (NTIS)

On May 18, 2011, a 43-year-old male volunteer fire fighter (FF) suffered a cardiac event en route to a structure fire. While riding in the cab of the apparatus, the FF complained of chest pains. Upon arrival at the fire scene 3 or 4 minutes later, crew me...

C. S. Ross T. Hales

2012-01-01

365

Cardiac Resynchronization Therapy Upregulates Cardiac Autonomic Control  

PubMed Central

Objective: To determine the effect of cardiac resynchronization therapy (CRT) on sympathetic nervous function in heart failure (HF). Background: Neurohormonal dysregulation and cardiac autonomic dysfunction are associated with HF and contribute to HF progression and its poor prognosis. We hypothesized that mechanical resynchronization improves cardiac sympathetic function in HF. Methods: Sixteen consecutive patients receiving CRT for advanced cardiomyopathy and 10 controls were included in this prospective study. NYHA class, 6-minute walk distance, echocardiographic parameters, plasma norepinephrine (NE) were assessed at baseline, 3-month and 6-month follow-up. Cardiac sympathetic function was determined by 123iodine metaiodobenzylguanidine (123I-MIBG) scintigraphy and 24-hour ambulatory electrocardiography. Results: Along with improvement in NYHA class (3.1 ± 0.3 to 2.1 ± 0.4, P < 0.001) and LVEF (23 ± 6% to 33 ± 12%, P < 0.001 delayed heart/mediastinum (H/M) 123 I-MIBG ratio increased significantly (1.8 ± 0.7 to 2.1 ± 0.6, P = 0.04) while the H/M 123I-MIBG washout rate decreased significantly (54 ± 25% to 34± 24%, P = 0.01) from baseline to 6-month follow-up. The heart rate variability (HRV) measured in SD of normal-to-normal intervals also increased significantly from baseline (82 ± 30 ms) to follow-up (111 ± 32 ms, P = 0.04). The improvement in NYHA after CRT was significantly associated with baseline 123I-MIBG H/M washout rate (r = 0.65, P = 0.03). The improvement in LVESV index was associated with baseline 123I-MIBG delayed H/M ratio (r = ?0.67, P = 0.02) and H/M washout rate (r = 0.65, P = 0.03). Conclusion: After CRT, improvements in cardiac symptoms and LV function were accompanied by rebalanced cardiac autonomic control as measured by 123I-MIBG and HRV.

CHA, YONG-MEI; OH, JAE; MIYAZAKI, CHINAMI; HAYES, DAVID L.; REA, ROBERT F.; SHEN, WIN-KUANG; ASIRVATHAM, SAMUEL J.; KEMP, BRAD J.; HODGE, DAVID O.; CHEN, PENG-SHENG; CHAREONTHAITAWEE, PANITHAYA

2009-01-01

366

About Cardiac Arrest  

MedlinePLUS

... High Blood Pressure Tools & Resources Stroke More About Cardiac Arrest Updated:Nov 25,2013 What is cardiac arrest? ... content was last reviewed on 02/26/2013. Cardiac Arrest • Home • About Cardiac Arrest • Warning Signs for Cardiac ...

367

Responses of Atlantic Salmon Parr to Output of Pulsed Ultrasonic Transmitters  

Microsoft Academic Search

The output from some pulsed ultrasonic transmitters commonly used in fish movement studies is faintly audible to humans. This study was undertaken to determine if the output from these and some other transmitters is detectable by Atlantic salmon (Salmo salar) parr. Classical conditioning of cardiac deceleration was attempted using the transmitter's output as the conditioned stimulus. The results from 29

DOUGLAS E. FACEY; JAMES D. MCCLEAVE; GLEN E. DOYON

1977-01-01

368

Assessment of cardiac function and myocardial morphology using small animal Look-Locker inversion recovery (SALLI) MRI in rats.  

PubMed

Small animal magnetic resonance imaging is an important tool to study cardiac function and changes in myocardial tissue. The high heart rates of small animals (200 to 600 beats/min) have previously limited the role of CMR imaging. Small animal Look-Locker inversion recovery (SALLI) is a T1 mapping sequence for small animals to overcome this problem. T1 maps provide quantitative information about tissue alterations and contrast agent kinetics. It is also possible to detect diffuse myocardial processes such as interstitial fibrosis or edema. Furthermore, from a single set of image data, it is possible to examine heart function and myocardial scarring by generating cine and inversion recovery-prepared late gadolinium enhancement-type MR images. The presented video shows step-by-step the procedures to perform small animal CMR imaging. Here it is presented with a healthy Sprague-Dawley rat, however naturally it can be extended to different cardiac small animal models. PMID:23912668

Jeuthe, Sarah; O H-Ici, Darach; Kemnitz, Ulrich; Dietrich, Thore; Schnackenburg, Bernhard; Berger, Felix; Kuehne, Titus; Messroghli, Daniel

2013-01-01

369

Magnetic Resonance Elastography as a Method for the Assessment of Effective Myocardial Stiffness throughout the Cardiac Cycle  

PubMed Central

Magnetic resonance elastography (MRE) is a noninvasive technique in which images of externally generated waves propagating in tissue are used to measure stiffness. The first aim is to determine, from a range of driver configurations the optimal driver for the purpose of generating waves within the heart in vivo. The second aim is to quantify the shear stiffness of normal myocardium throughout the cardiac cycle using MRE and to compare MRE stiffness to left ventricular (LV) chamber pressure in an in vivo pig model. MRE was performed in 6-pigs with 6-different driver setups including no motion, 3-noninvasive drivers and 2-invasive drivers. MRE wave displacement amplitudes were calculated for each driver. During the same MRI examination, LV pressure and MRI-measured LV volume were obtained, and MRE myocardial stiffness was calculated for 20 phases of the cardiac cycle. No discernible waves were imaged when no external motion was applied, and a single pneumatic drum driver produced higher amplitude waves than the other noninvasive drivers (P <0.05). Pressure-volume loops overlaid onto stiffness-volume loops showed good visual agreement. Pressure and MRE-measured effective stiffness showed good correlation (R2 = 0.84). MRE shows potential as a noninvasive method for estimating effective myocardial stiffness throughout the cardiac cycle.

Kolipaka, Arunark; Araoz, Philip A.; McGee, Kiaran P.; Manduca, Armando; Ehman, Richard L.

2011-01-01

370

Automated quantification of cardiac short-axis multi-slice CT images for assessment of left ventricular global function  

NASA Astrophysics Data System (ADS)

This paper describes a method for automatic contour detection in reformatted short-axis (SA) cardiac computed tomography (CT) using a virtual exploring robot. The robot is a tricycle with a steering front wheel. Its motion obeys a set of kinematic equations and is subject to the non-holonomic constraints. The robot is designed to navigate in the binary representation of a cardiac image, consisting of the allowed navigational and obstacle spaces. It is initially positioned inside the allowed navigational space. Avoiding obstacles, the robot autonomously cruises through the navigational space and collects information about the location of the left ventricular (LV) boundaries. Consequently, the obtained information is used to reconstruct the endocardial and epicardial contours. Validation of the method was performed on in-vivo multislice multiphase short-axis cardiac CT images of ten subjects. Results showed good correlation between the quantitative parameters, computed from manual and automatic segmentation: for end-diastolic volume (EDV) r=0.99, for end-systolic volume (ESV) r=0.98, ejection fraction (EF) r=0.83, and LV mass (LVM) r=0.95.

Danilouchkine, Mikhail G.; Admiraal-Behloul, Faiza; van der Geest, Rob J.; Lelieveldt, Boudewijn P. F.; Reiber, Johan H. C.

2005-04-01

371

[High-output congestive heart failure due to congenital iliac arteriovenous fistula].  

PubMed

A 54-year-old man was admitted to hospital because of chronic right-sided heart failure. Echocardiography revealed dilatation of all chambers of the heart. Cardiac catheterization showed high-output heart failure due to left-to-right shunt caused by a congenital fistula between the right iliac artery and vein. The fistula was closed by percutaneous implantation of a covered stent. 15 months later, the patient denied any cardiac complaint. On echocardiography, the size of all chambers had almost normalized, cardiac catheterization proved a normal cardiac output. By angiography and oximetry, neither a residual nor a relapsing shunt were seen. PMID:17149681

Götze, Christine J; Secknus, Maria A; Strauss, Hans J; Lauer, Bernward; Ohlow, Marc A

2006-11-01

372

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

373

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

374

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.

2012-01-01

375

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

376

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.

377

Cardiac Ochronosis  

PubMed Central

We report the case of 67-year-old woman who underwent aortic valve replacement and mitral valve repair due to ochronotic valvular disease (alkaptonuria), which was diagnosed incidentally during cardiac surgery.

Erek, Ersin; Casselman, Filip P.A.; Vanermen, Hugo

2004-01-01

378

Cardiac catheterization  

MedlinePLUS

... amyloidosis Causes of congestive heart failure or cardiomyopathy Coronary artery disease Heart defects that are present at birth ( ... include: Cardiac tamponade Heart attack Injury to a coronary artery Irregular heartbeat Low blood pressure Reaction to the ...

379

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 ...

380

Cardiac MRI  

MedlinePLUS

... from the NHLBI on Twitter. What Is Cardiac MRI? Magnetic resonance imaging (MRI) is a safe, noninvasive test that creates detailed ... and no instruments are inserted into your body. MRI uses radio waves, magnets, and a computer to ...