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Sample records for maintain cardiac output

  1. Cardiac output after burn injury.

    PubMed Central

    Porter, J. M.; Shakespeare, P. G.

    1984-01-01

    Cardiac output after burn injury has been measured by the non-invasive method of impedance plethysmography. An initial study of 143 normal subjects was undertaken in order to investigate variations in cardiac output with age. Fifteen patients were monitored during resuscitation after extensive burns. Fourteen patients showed a depression of stroke volume below the lower limits of the normal range, derived from the initial study on normal people. PMID:6691694

  2. Mathematics and the Heart: Understanding Cardiac Output

    ERIC Educational Resources Information Center

    Champanerkar, Jyoti

    2013-01-01

    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

  3. Mathematics and the Heart: Understanding Cardiac Output

    ERIC Educational Resources Information Center

    Champanerkar, Jyoti

    2013-01-01

    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…

  4. Methods in pharmacology: measurement of cardiac output

    PubMed Central

    Geerts, Bart F; Aarts, Leon P; Jansen, Jos R

    2011-01-01

    Many methods of cardiac output measurement have been developed, but the number of methods useful for human pharmacological studies is limited. The ‘holy grail’ for the measurement of cardiac output would be a method that is accurate, precise, operator independent, fast responding, non-invasive, continuous, easy to use, cheap and safe. This method does not exist today. In this review on cardiac output methods used in pharmacology, the Fick principle, indicator dilution techniques, arterial pulse contour analysis, ultrasound and bio-impedance are reviewed. PMID:21284692

  5. Pathophysiology of Post-Operative Low Cardiac Output Syndrome.

    PubMed

    Epting, Conrad L; McBride, Mary E; Wald, Eric L; Costello, John M

    2016-01-01

    Low cardiac output syndrome frequently complicates the post-operative care of infants and children following cardiac surgery. The onset of low cardiac output follows a predictable course in the hours following cardiopulmonary bypass, as myocardial performance declines in the face of an elevated demand for cardiac output. When demand outstrips supply, shock ensues, and early recognition and intervention can decrease mortality. Multifactorial in etiology, this article will discuss the pathophysiology of low cardiac output syndrome, including myocardial depression following bypass, altered cardiac loading conditions, and inflammation driving a hypermetabolic state. Contributions from altered neurohormonal, thyroid, and adrenal axes will also be discussed. Sources included the clinical experiences of four cardiac intensivists, supported throughout by primary sources and relevant reviews obtained through PubMed searches and from seminal textbooks in the field. This article addresses the second of eight topics comprising the special issue entitled "Pharmacologic strategies with afterload reduction in low cardiac output syndrome after pediatric cardiac surgery". PMID:26463989

  6. Methods and apparatus for determining cardiac output

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  7. Bioimpedance and bioreactance methods for monitoring cardiac output.

    PubMed

    Jakovljevic, Djordje G; Trenell, Michael I; MacGowan, Guy A

    2014-12-01

    Noninvasive continuous cardiac output monitoring may have wide clinical applications in anaesthesiology, emergency care and cardiology. It can improve outcomes, establish diagnosis, guide therapy and help risk stratification. The present article describes the theory behind the two noninvasive continuous monitoring methods for cardiac output assessment such as bioimpedance and bioreactance. The review discusses the advantages and disadvantages of these methods and highlights the recent method comparison studies. The use of bioimpedance and bioreactance to estimate cardiac output under haemodynamic challenges is also discussed. In particular, the article focuses on performance of the two methods in the assessment of fluid responsiveness using passive leg raising test and cardiac output response to exercise stress testing. PMID:25480768

  8. Sham-feeding decreases cardiac output in normal subjects.

    PubMed

    Andersen, H B; Jensen, E W; Madsbad, S; Nielsen, S L; Burcharth, F; Christensen, N J

    1992-07-01

    The cardiovascular effect of sham-feeding was measured in seven healthy non-obese human subjects by the Fick principle using the carbon dioxide rebreathing method. The subjects were resting in the sitting position and were exposed to the sight and smell but not the taste of a breakfast meal. Cardiac output decreased significantly from a mean value of 4.0 1 min-1 to 3.5 1 min-1 during sham-feeding (Friedman, P = 0.004). The cardiac output returned to basal values in all seven subjects when the sensory stimulus was removed. The decrease in cardiac output was due to a decreased stroke volume, whereas heart rate and blood pressure did not change. The mechanism of the decrease in cardiac output during sham-feeding remains to be established. PMID:1505165

  9. Red cell volume and cardiac output in anaemic preterm infants.

    PubMed Central

    Hudson, I; Cooke, A; Holland, B; Houston, A; Jones, J G; Turner, T; Wardrop, C A

    1990-01-01

    To test the hypothesis that haemoglobin concentration is a poor predictor of benefit from transfusion in preterm infants, and that red cell volume is the most important indicator of anaemia, 24 preterm infants receiving red cell transfusions had red cell volume, haemoglobin concentration, and cardiac output measured before and after transfusion. Red cell volume was measured either using dilution of autologous fetal haemoglobin with donor adult haemoglobin, or with a new technique using biotin as a red cell label. The two techniques give similar results. Mean (SD) values before transfusion were 27.4 (13.3), and after transfusion 45.0 (13.7) ml/kg. Cardiac output was measured using imaging and Doppler ultrasonography, and fell with transfusion from mean 286 (121) to 251 (95.6) ml/kg/min. The red cell volume before transfusion correlated well with changes in cardiac output following transfusion, infants with a red cell volume before transfusion of less than 25 ml/kg showing a fall in cardiac output, and those with a red cell volume of greater than 25 ml/kg not showing a significant fall. There was no correlation between haemoglobin concentration, packed cell volume, or change in packed cell volume with changes in cardiac output after transfusion. A red cell volume of 25 ml/kg seems to be critical in preterm infants with anaemia, and infants with values below this are those most likely to benefit from transfusion. PMID:2386399

  10. Evaluation of heavy water for indicator dilution cardiac output measurement

    SciTech Connect

    Schreiner, M.S.; Leksell, L.G.; Neufeld, G.R. )

    1989-10-01

    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.

  11. Redistribution of cardiac output in response to heat exposure in the pony.

    PubMed

    McConaghy, F F; Hodgson, D R; Rose, R J; Hales, J R

    1996-07-01

    Radioactive microspheres were used to measure cardiac output and blood flow to most major tissues in 4 ponies at rest in thermoneutral (16 degrees C/60% RH) and mildly hot (41 degrees C/34% RH) environments. In response to heat stress there were increases in cardiac output (2-fold), respiratory frequency (5-fold), blood flow to the skin of the body (3-fold), and limbs (50%), respiratory muscles (2-fold) and the upper respiratory tract (3-fold). Ponies were able to maintain body temperature in the hot environment by increasing blood flow to the tissues involved in heat dissipation, while blood flow to all other tissues remained stable. This was achieved by increasing the cardiac output without need for reduction of blood flow to other tissues. PMID:8894549

  12. Evaluation of noninvasive cardiac output methods during exercise

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  13. Continuous cardiac output measurements in the perioperative period.

    PubMed

    Jakobsen, C J; Melsen, N C; Andresen, E B

    1995-05-01

    Management of critically ill patients is based on knowledge of fundamental physiologic variables. Automatized and continuous measurement of these variables is preferable. A new system based upon the thermodilution method has been developed to measure cardiac output automatically and continuously. We evaluated the system in the potentially unstable perioperative period with possible great and rapid changes in cardiac output. Twenty patients, scheduled for open heart or abdominal aortic aneurysm surgery, were included in the study, which was approved by the local ethical committee. The patients were monitored up to 30 hours. At random intervals five, iced, bolus thermodilution cardiac output (BCO) determinations were made and compared to the continuous cardiac output measurements (CCO). Two hundred and thirty-one pairs of data were obtained. The cardiac outputs ranged from 2.5-14.9 l.min-1. The absolute bias was 0.31 l.min-1 (95% limits of agreement -14 l.min-1 to 2.0 l.min-1). The mean relative error was 4.7% with a standard deviation of the relative error of 15.4%. The linear regression was represented by: CCO = 1,1352.BCO-0.36. The correlation coefficient R was 0.90 (P < 0.001). In conclusion, the CCO measurement technique is a promising clinical method. The method is straightforward, requires no calibration, is independent of vascular geometry and measures with its limitations volumetric flow. Finally automatic and continuous patient monitoring provides more information and has potential to reveal previously undetected haemodynamic events. PMID:7676783

  14. Measurement of cardiac output from dynamic pulmonary circulation time CT

    SciTech Connect

    Yee, Seonghwan; Scalzetti, Ernest M.

    2014-06-15

    Purpose: To introduce a method of estimating cardiac output from the dynamic pulmonary circulation time CT that is primarily used to determine the optimal time window of CT pulmonary angiography (CTPA). Methods: Dynamic pulmonary circulation time CT series, acquired for eight patients, were retrospectively analyzed. The dynamic CT series was acquired, prior to the main CTPA, in cine mode (1 frame/s) for a single slice at the level of the main pulmonary artery covering the cross sections of ascending aorta (AA) and descending aorta (DA) during the infusion of iodinated contrast. The time series of contrast changes obtained for DA, which is the downstream of AA, was assumed to be related to the time series for AA by the convolution with a delay function. The delay time constant in the delay function, representing the average time interval between the cross sections of AA and DA, was determined by least square error fitting between the convoluted AA time series and the DA time series. The cardiac output was then calculated by dividing the volume of the aortic arch between the cross sections of AA and DA (estimated from the single slice CT image) by the average time interval, and multiplying the result by a correction factor. Results: The mean cardiac output value for the six patients was 5.11 (l/min) (with a standard deviation of 1.57 l/min), which is in good agreement with the literature value; the data for the other two patients were too noisy for processing. Conclusions: The dynamic single-slice pulmonary circulation time CT series also can be used to estimate cardiac output.

  15. Noninvasive cardiac output measurements in patients with pulmonary hypertension.

    PubMed

    Rich, Jonathan D; Archer, Stephen L; Rich, Stuart

    2013-07-01

    Pulmonary hypertension (PH) is characterised by a progressive decline in cardiac output (CO) and right heart failure. NICOM® (noninvasive cardiac output monitor) is a bioreactance-based technology that has been broadly validated, but its specific application in right heart failure and PH is unknown. Cardiac catheterisation was performed in 50 consecutive patients with PH. CO measurements were performed using three different methods (thermodilution, Fick and NICOM) at baseline and after vasodilator challenge. We compared the precision (coefficient of variation) and accuracy of NICOM compared to thermodilution and Fick. The mean CO (L·min(-1)) at baseline as measured by the three methods was 4.73±1.15 (NICOM), 5.69±1.74 (thermodilution) and 4.84±1.39 (Fick). CO measured by NICOM was more precise than by thermodilution (3.5±0.3% versus 9.6±6.1%, p<0.001). Bland-Altman analyses comparing NICOM to thermodilution and Fick revealed bias and 95% limits of agreement that were comparable to those comparing Fick to thermodilution. All three CO methods detected an increase in CO in response to vasodilator challenge. CO measured via NICOM is precise and reliably measures CO at rest and changes in CO with vasodilator challenge in patients with PH. NICOM may allow for the noninvasive haemodynamic assessment of patients with PH and their response to therapy. PMID:23100501

  16. Significant role of estrogen in maintaining cardiac mitochondrial functions.

    PubMed

    Rattanasopa, Chutima; Phungphong, Sukanya; Wattanapermpool, Jonggonnee; Bupha-Intr, Tepmanas

    2015-03-01

    Increased susceptibility to stress-induced myocardial damage is a significant concern in addition to decreased cardiac performance in postmenopausal females. To determine the potential mechanisms underlying myocardial vulnerability after deprivation of female sex hormones, cardiac mitochondrial function is determined in 10-week ovariectomized rats (OVX). Significant mitochondrial swelling in the heart of OVX rats is observed. This structural alteration can be prevented with either estrogen or progesterone supplementation. Using an isolated mitochondrial preparation, a decrease in ATP synthesis by complex I activation in an OVX rat is completely restored by estrogen, but not progesterone. At basal activation, reactive oxygen species (ROS) production from the mitochondria is not affected by the ovariectomy. However, after incubated in the presence of either high Ca(2+) or antimycin-A, there is a significantly higher mitochondrial ROS production in the OVX sample compared to the control. This increased stress-induced ROS production is not observed in the preparation isolated from the hearts of OVX rats with estrogen or progesterone supplementation. However, deprivation of female sex hormones has no effect on the protein expression of electron transport chain complexes, mitofusin 2, or superoxide dismutase 2. Taken together, these findings suggest that female sex hormones, estrogen and progesterone, play significant regulatory roles in maintaining normal mitochondrial properties by stabilizing the structural assembly of mitochondria as well as attenuating mitochondrial ROS production. Estrogen, but not progesterone, also plays an important role in modulating mitochondrial ATP synthesis. PMID:25448746

  17. Cardiac Output Assessed by Invasive and Minimally Invasive Techniques

    PubMed Central

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

    2011-01-01

    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. PMID:21776254

  18. Continuous cardiac output monitoring by peripheral blood pressure waveform analysis.

    PubMed

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

    2006-03-01

    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

  19. Measurement of cardiac output in children by bioreactance.

    PubMed

    Ballestero, Yolanda; López-Herce, Jesús; Urbano, Javier; Solana, Maria José; Botrán, Marta; Bellón, Jose M; Carrillo, Angel

    2011-04-01

    The objective of this study was to evaluate a new bioreactance method for noninvasive cardiac output (CO) measurement (NICOM) in children. Ten patients between 1 and 144 months of age and with no hemodynamic disturbances were studied. Using bioreactance, heart rate (HR), mean arterial pressure (MAP), and cardiac index (CI) measurements were made every 6-8 h. CI was 2.4 ± 1.03 l/min/1.73 m(2) (range 1-4.9 l/min/1.73 m(2)); There were significant correlations between CI and age (r = 0.50, P = 0.003), weight (r = 0.66, P < 0.001), and MAP (r = 0.369, P = 0.037). Significant differences in CI (P < 0.001) were detected between children weighing <10 kg (1.9 ± 0.73 l/min/1.73 m(2); range 1-3.2), 10-20 kg (2.07 ± 0.7 l/min/1.73 m(2); range 1-3.6), and >20 kg (3.7 ± 0.8 l/min/1.73 m(2); range 2.4-4.9). We conclude that the CI measured by bioreactance in children varies with the age and weight of the patients and is lower than the normal range in a large percentage of measurements. These data suggest that this method is not useful for evaluating CI in small children. PMID:21318463

  20. Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients.

    PubMed

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

    2010-01-01

    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

  1. Cardiac output monitoring by echocardiography: should we pass on Swan-Ganz catheters?

    PubMed Central

    Perrino, A. C.

    1993-01-01

    Transesophageal echocardiography offers a noninvasive technique for the continuous monitoring of cardiac performance. The combination of 2-dimensional echocardiography and Doppler velocitometry provide assessment of cardiac anatomy, valve function and, ventricular loading conditions. Although transesophageal echocardiography has become accepted for perioperative monitoring, it is typically used in conjunction with Swan-Ganz catheterization. To supplant Swan-Ganz catheters, an echocardiographic technique to monitor cardiac output is necessary. Despite considerable effort to achieve this goal, a satisfactory technique has been difficult to realize. This paper discusses the role of cardiac output monitoring in perioperative care and critically examines echocardiographic techniques for cardiac output monitoring. Images Figure 4 Figure 7 Figure 10 PMID:7825341

  2. Maximal Cardiac Output Determines 6 Minutes Walking Distance in Pulmonary Hypertension

    PubMed Central

    Deboeck, Gal; Taboada, Dolores; Hagan, Guy; Treacy, Carmen; Page, Kathy; Sheares, Karen; Naeije, Robert; Pepke-Zaba, Joanna

    2014-01-01

    Purpose The 6 minutes walk test (6MWT) is often shown to be the best predictor of mortality in pulmonary hypertension (PH) probably because it challenges the failing heart to deliver adequate cardiac output. We hypothesised that the 6MWT elicits maximal cardiac output as measured during a maximal cardiopulmonary exercise testing (CPET). Methods 18 patients with chronic thromboembolic pulmonary hypertension (n?=?12) or pulmonary arterial hypertension (n?=?6) and 10 healthy subjects performed a 6MWT and CPET with measurements of cardiac output (non invasive rebreathing device) before and directly after exercise. Heart rate was measured during 6MWT with a cardiofrequence meter. Results Cardiac output and heart rate measured at the end of the 6MWT were linearly related to 6MW distance (meanSD: 49087 m). Patients with a high NT-pro-BNP achieve a maximum cardiac output during the 6MWT, while in normal subjects and in patients with a low-normal NT-proBNP, cardiac output at the end of a 6MWT was lower than achieved at maximum exercise during a CPET. In both cases, heart rate is the major determinant of exercise-induced increase in cardiac output. However, stroke volume increased during CPET in healthy subjects, not in PH patients. Conclusion Maximal cardiac output is elicited by 6MWT in PH patients with failing right ventricle. Cardiac output increase is dependent on chronotropic response in patients with PH. PMID:24647561

  3. Minimally invasive or noninvasive cardiac output measurement: an update.

    PubMed

    Sangkum, Lisa; Liu, Geoffrey L; Yu, Ling; Yan, Hong; Kaye, Alan D; Liu, Henry

    2016-06-01

    Although cardiac output (CO) by pulmonary artery catheterization (PAC) has been an important guideline in clinical management for more than four decades, some studies have questioned the clinical efficacy of CO in certain patient populations. Further, the use of CO by PAC has been linked to numerous complications including dysrhythmia, infection, rupture of pulmonary artery, injury to adjacent arteries, embolization, pulmonary infarction, cardiac valvular damage, pericardial effusion, and intracardiac catheter knotting. The use of PAC has been steadily declining over the past two decades. Minimally invasive and noninvasive CO monitoring have been studied in the past two decades with some evidence of efficacy. Several different devices based on pulse contour analysis are available currently, including the uncalibrated FloTrac/Vigileo system and the calibrated PiCCO and LiDCO systems. The pressure-recording analytical method (PRAM) system requires only an arterial line and is commercially available as the MostCare system. Transesophageal echocardiography (TEE) can measure CO by non-Doppler- or Doppler-based methods. The partial CO2 rebreathing technique, another method to measure CO, is marketed by Novametrix Medical Systems as the NICO system. Thoracic electrical bioimpedance (TEB) and electric bioreactance (EB) are totally noninvasive CO monitoring. Nexfin HD and the newer ClearSight systems are examples of noninvasive CO monitoring devices currently being marketed by Edwards Lifesciences. The developing focus in CO monitoring devices appears to be shifting to tissue perfusion and microcirculatory flow and aimed more at markers that indicate the effectiveness of circulatory and microcirculatory resuscitations. PMID:26961819

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

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

    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.

  5. Comparison of Cardiac Output Responses to 2,4-Dinitrophenol-Induced Hypermetabolism and Muscular Work

    PubMed Central

    Liang, Chang-Seng; Hood, William B.

    1973-01-01

    Both electrically induced exercise and infusion of 2,4-dinitrophenol (DNP) increased oxygen consumption and tissue metabolism in chloralose-anesthetized dogs. Cardiac output increased with oxygen consumption at the same rate in both experimental conditions. The increase in cardiac output induced by exercise was, as expected, accompanied by increases in both lactate-to-pyruvate ratio and “excess lactate” in arterial blood. However, these parameters did not increase after DNP infusion until the rate of oxygen consumption had increased four- to fivefold, perhaps due to facilitation of mitochondrial electron transport by DNP. Anaerobic tissue metabolism therefore probably did not contribute significantly to increased cardiac output during the mild-to-moderate tissue hypermetabolism induced by DNP. The increased cardiac output may have been the result of metabolic changes common to both exercise and DNP infusion; muscular activity alone may not have been the primary determinant of the cardiac output response during exercise. PMID:4727459

  6. Noninvasive measurements of cardiac output in sheep: an improved thermometry method.

    PubMed

    Serikov, V B; Jerome, E H

    1997-10-01

    In 25 sheep and 5 goats, which were anesthetized, intubated and mechanically ventilated a sudden decrease in the inspired gas humidity was used to cool the lungs. The dynamics of the temperature of expired gas and its relationship to ventilation rate and cardiac output measured by thermodilution were investigated. In six animals minute ventilation was changed at a stable cardiac output and in 14 animals cardiac output was changed by infusion of saline or by bleeding at a constant ventilation. The difference between the blood temperature and the expired gas temperature at a steady state is proportional to minute ventilation and is inversely proportional to the cardiac output. The inverse time constant of the decay of temperature of the expired gas is proportional to the cardiac output and does not depend on ventilation. The lungs function as a natural humidifier of the respiratory gases with an inner heat source from the pulmonary circulation and an outer heat sink to the expired gas. A simple lumped heat capacity model of non-steady state heat exchange in the lungs was developed, which may be used as a basis for the non-invasive method for determining cardiac output. The coefficient of the lung thermal conductivity (KT/(rho WCpW) = 0.156 +/- 0.056) was determined and applied to measure cardiac output in a separate group, designed as a prospective study. When calculations of cardiac output were done based on the lung mass, estimated from the body weight (12 g/kg), bias and precision compared with thermodilution were -0.27 l/min and 0.38 l/min, respectively in 15 animals. Measurements of blood flow by the air thermometry correlated very well with thermodilution cardiac output (r = 0.92). Thermometry of the expired gas is a promising approach to measure the cardiac output non-invasively. PMID:9457695

  7. Mechanisms Regulating the Cardiac Output Response to Cyanide Infusion, a Model of Hypoxia

    PubMed Central

    Liang, Chang-seng; Huckabee, William E.

    1973-01-01

    When tissue metabolic changes like those of hypoxia were induced by intra-aortic infusion of cyanide in dogs, cardiac output began to increase after 3 to 5 min, reached a peak (220% of the control value) at 15 min, and returned to control in 40 min. This pattern of cardiac output rise was not altered by vagotomy with or without atropine pretreatment. However, this cardiac output response could be differentiated into three phases by pretreating the animals with agents that block specific activities of the sympatho-adrenal system. First, ganglionic blockade produced by mecamylamine or sympathetic nerve blockade by bretylium abolished the middle phase of the cardiac output seen in the untreated animal, but early and late phases still could be discerned. Second, beta-adrenergic receptor blockade produced by propranolol shortened the total duration of the cardiac output rise by abolishing the late phase. Third, when given together, propranolol and mecamylamine (or bretylium) prevented most of the cardiac output rise that follows the early phase. When cyanide was given to splenectomized dogs, the duration of the cardiac output response was not shortened, but the response became biphasic, resembling that seen after chemical sympathectomy. A similar biphasic response of the cardiac output also resulted from splenic denervation; sham operation or nephrectomy had no effect on the monophasic pattern of the normal response. Splenic venous blood obtained from cyanide-treated dogs, when infused intraportally, caused an increase in cardiac output in recipient dogs; similar infusion of arterial blood had no effects. These results suggest that the cardiac output response to cyanide infusion consists of three components: an early phase, related neither to the autonomic nervous system nor to circulating catecholamines; a middle phase, caused by a nonadrenergic humoral substance released from the spleen by sympathetic stimulation; and a late phase, dependent upon adrenergic receptors but not upon sympathetic transmission. PMID:4750445

  8. High flow variant postural orthostatic tachycardia syndrome amplifies the cardiac output response to exercise in adolescents

    PubMed Central

    Pianosi, Paolo T.; Goodloe, Adele H.; Soma, David; Parker, Ken O.; Brands, Chad K.; Fischer, Philip R.

    2014-01-01

    Abstract Postural orthostatic tachycardia syndrome (POTS) is characterized by chronic fatigue and dizziness and affected individuals by definition have orthostatic intolerance and tachycardia. There is considerable overlap of symptoms in patients with POTS and chronic fatigue syndrome (CFS), prompting speculation that POTS is akin to a deconditioned state. We previously showed that adolescents with postural orthostatic tachycardia syndrome (POTS) have excessive heart rate (HR) during, and slower HR recovery after, exercise – hallmarks of deconditioning. We also noted exaggerated cardiac output during exercise which led us to hypothesize that tachycardia could be a manifestation of a high output state rather than a consequence of deconditioning. We audited records of adolescents presenting with long‐standing history of any mix of fatigue, dizziness, nausea, who underwent both head‐up tilt table test and maximal exercise testing with measurement of cardiac output at rest plus 2–3 levels of exercise, and determined the cardiac output () versus oxygen uptake () relationship. Subjects with chronic fatigue were diagnosed with POTS if their HR rose ≥40 beat·min−1 with head‐up tilt. Among 107 POTS patients the distribution of slopes for the , relationship was skewed toward higher slopes but showed two peaks with a split at ~7.0 L·min−1 per L·min−1, designated as normal (5.08 ± 1.17, N = 66) and hyperkinetic (8.99 ± 1.31, N = 41) subgroups. In contrast, cardiac output rose appropriately with in 141 patients with chronic fatigue but without POTS, exhibiting a normal distribution and an average slope of 6.10 ± 2.09 L·min−1 per L·min−1. Mean arterial blood pressure and pulse pressure from rest to exercise rose similarly in both groups. We conclude that 40% of POTS adolescents demonstrate a hyperkinetic circulation during exercise. We attribute this to failure of normal regional vasoconstriction during exercise, such that patients must increase flow through an inappropriately vasodilated systemic circulation to maintain perfusion pressure. PMID:25168872

  9. Continuous monitoring of cardiac output from TCG signals.

    PubMed

    Keenan, D B

    2004-01-01

    Continuous measurement of cardiac output (CO) is an important and difficult measure to obtain in an ambulatory environment. A novel ambulatory monitoring system (LifeShirt, VivoMetrics, Inc., Ventura, CA, USA) with three Inductive Plethysmographic (IP) sensors embedded in a garment, enables continuous monitoring of respiration from the ribcage and abdomen areas, and captures thoracocardiograph (TCG) signals from the thorax at the level of the left ventricle. This TCG signal provides a non-invasive measure of the volumetric contractions of the heart. The raw TCG signal must undergo extensive signal processing and digital filtering to extract a volume curve similar to the ventricular volume curve obtained through echocardiography. Typically the respiratory component has an amplitude of over twenty times that of the stroke volume curve. This investigation compares various signal processing algorithms such as spectral subtraction and adaptive filtering to separate these 2 components, which can occupy the same frequency band. These algorithms make use of the ribcage and abdominal signals to predict the respiratory component within the TCG signal. A dual axis accelerometer that measures posture and levels of activity aids filtering movement artifact. With the addition of a single lead ECG, ensemble averaging is used to smooth artifact in the signal, and CO may be obtained by including a heart rate measure. Additional measures can be derived including left ventricular systolic time intervals such as Pre-ejection period, Peak ejection rate and time to peak ejection rate. The results show that increases and decreases in SV and CO can be measured over time. PMID:15133982

  10. [Mechanisms of changes in cardiac output during stimulation of afferent fibers of a somatic nerve].

    PubMed

    Osadchi?, L I; Balueva, T V; Sergeev, I V

    1985-06-01

    In anesthetized cats, the technique of electromagnetic expenditure-metry aided to study changes of the cardiac output and venous inflow in pressor responses to stimulation of the tibial nerve's afferent fibers. The cardiac output was found to increase in 47% of observations which was accompanied by increased venous inflow in half of the cases and by decreased one in 1/3 of observations. Vagotomy as well as suppression of the efferent link of cardiac responses with atropin and obsidan induced shifts of the cardiac output in the somatic nerve stimulation. The optimum level of arterial pressure responses was revealed peculiar by positive shifts of the cardiac output in pressor responses to the above action. PMID:2993045

  11. Noninvasive continuous cardiac output monitoring in perioperative and intensive care medicine.

    PubMed

    Saugel, B; Cecconi, M; Wagner, J Y; Reuter, D A

    2015-04-01

    The determination of blood flow, i.e. cardiac output, is an integral part of haemodynamic monitoring. This is a review on noninvasive continuous cardiac output monitoring in perioperative and intensive care medicine. We present the underlying principles and validation data of the following technologies: thoracic electrical bioimpedance, thoracic bioreactance, vascular unloading technique, pulse wave transit time, and radial artery applanation tonometry. According to clinical studies, these technologies are capable of providing cardiac output readings noninvasively and continuously. They, therefore, might prove to be innovative tools for the assessment of advanced haemodynamic variables at the bedside. However, for most technologies there are conflicting data regarding the measurement performance in comparison with reference methods for cardiac output assessment. In addition, each of the reviewed technology has its own limitations regarding applicability in the clinical setting. In validation studies comparing cardiac output measurements using these noninvasive technologies in comparison with a criterion standard method, it is crucial to correctly apply statistical methods for the assessment of a technology's accuracy, precision, and trending capability. Uniform definitions for 'clinically acceptable agreement' between innovative noninvasive cardiac output monitoring systems and criterion standard methods are currently missing. Further research must aim to further develop the different technologies for noninvasive continuous cardiac output determination with regard to signal recording, signal processing, and clinical applicability. PMID:25596280

  12. Reproducibility of cardiac power output and other cardiopulmonary exercise indices in patients with chronic heart failure.

    PubMed

    Jakovljevic, Djordje G; Seferovic, Petar M; Nunan, David; Donovan, Gay; Trenell, Michael I; Grocott-Mason, Richard; Brodie, David A

    2012-02-01

    Cardiac power output is a direct measure of overall cardiac function that integrates both flow- and pressure-generating capacities of the heart. The present study assessed the reproducibility of cardiac power output and other more commonly reported cardiopulmonary exercise variables in patients with chronic heart failure. Metabolic, ventilatory and non-invasive (inert gas re-breathing) central haemodynamic measurements were undertaken at rest and near-maximal exercise of the modified Bruce protocol in 19 patients with stable chronic heart failure. The same procedure was repeated 7 days later to assess reproducibility. Cardiac power output was calculated as the product of cardiac output and mean arterial pressure. Resting central haemodynamic variables demonstrate low CV (coefficient of variation) (ranging from 3.4% for cardiac output and 5.6% for heart rate). The CV for resting metabolic and ventilatory measurements ranged from 8.2% for respiratory exchange ratio and 14.2% for absolute values of oxygen consumption. The CV of anaerobic threshold, peak oxygen consumption, carbon dioxide production and respiratory exchange ratio ranged from 3.8% (for anaerobic threshold) to 6.4% (for relative peak oxygen consumption), with minute ventilation having a CV of 11.1%. Near-maximal exercise cardiac power output and cardiac output had CVs of 4.1 and 2.2%, respectively. Cardiac power output demonstrates good reproducibility suggesting that there is no need for performing more than one cardiopulmonary exercise test. As a direct measure of cardiac function (dysfunction) and an excellent prognostic marker, it is strongly advised in the assessment of patients with chronic heart failure undergoing cardiopulmonary exercise testing. PMID:21883095

  13. In vitro evaluation of an ultrasonic cardiac output monitoring (USCOM) device.

    PubMed

    Gregory, Shaun D; Cooney, Helena; Diab, Sara; Anstey, Chris; Thom, Ogilvie; Fraser, John F

    2016-02-01

    Non-invasive cardiac output monitoring techniques provide high yield, low risk mechanisms to identify and individually treat shock in the emergency setting. The non-invasive ultrasonic cardiac output monitoring (USCOM) device uses an ultrasound probe applied externally to the chest; however limitations exist with previous validation strategies. This study presents the in vitro validation of the USCOM device against calibrated flow sensors and compares user variability in simulated healthy and septic conditions. A validated mock circulation loop was used to simulate each condition with a range of cardiac outputs (2-10 l/min) and heart rates (50-95 bpm). Three users with varying degrees of experience using the USCOM device measured cardiac output and heart rate by placing the ultrasound probe on the mock aorta. Users were blinded to the condition, heart rate and cardiac output which were randomly generated. Results were reported as linear regression slope (β). All users estimated heart rate in both conditions with reasonable accuracy (β = 0.86-1.01), while cardiac output in the sepsis condition was estimated with great precision (β = 1.03-1.04). Users generally overestimated the cardiac output in the healthy simulation (β = 1.07-1.26) and reported greater difficulty estimating reduced cardiac output compared with higher values. Although there was some variability between users, particularly in the healthy condition (P < 0.01), all estimations were within a clinically acceptable range. In this study the USCOM provided a suitable measurement of cardiac output and heart rate when compared with our in vitro system. It is a promising technique to assist with the identification and treatment of shock. PMID:25749977

  14. Shoshin Beriberi With Low Cardiac Output and Hemodynamic Deterioration Treated Dramatically by Thiamine Administration.

    PubMed

    Imamura, Teruhiko; Kinugawa, Koichiro

    2015-01-01

    "Shoshin beriberi", which is a fulminant form of cardiovascular beriberi accompanied by hemodynamic deterioration with high cardiac output and decreased systemic blood pressure, caused by thiamine deficiency due to alcoholic abuse or malnutrition, is often difficult to address because of its rarity and non-specific symptoms. We here present a patient with a history of alcoholic abuse who had suffered hemodynamic deterioration with extremely low cardiac output refractory to extracorporeal membrane oxygenation and intravenous catecholamine support, which was improved dramatically by bolus intravenous thiamine administration. Such a type with low cardiac output would be the most severe form of Shoshin beriberi, and cannot be rescued without diagnostic administration of thiamine. PMID:26346515

  15. Cardiac output measurement using a modified carbon dioxide Fick method: comparison analysis with pulmonary artery catheter method and pulse induced contour cardiac output method

    PubMed Central

    Li, Tong; Cai, Hongliu; Pan, Hui; Pu, Qibin

    2015-01-01

    Objectives: In the present study, cardiac output in mechanically ventilated patients were determined using three methods including modified CO2-Fick (mCO2F), pulmonary artery catheter (PAC), and pulse induced contour cardiac output (PiCCO) methods and the results were compared to assess the effectiveness of mCO2F method in measuring the cardiac output. Method: Mechanically ventilated and hemodynamically unstable patients (n=39) were sedated and intubated with Swan-Ganz or PiCCO arterial catheters. At the beginning of the experiment and at 4 h after the experiment, the CO2 concentration in expiratory air was measured through a CO2 monitor and it was used further in the cardiac output calculation using mCO2F method. The cardiac output was also determined using PAC and PiCCO methods. Results: The cardiac output determined by PAC and mCO2F method was not significantly (P>0.05) different [5.53±2.85 L.min-1 (PAC) and 5.96±2.92 L.min-1 (mCO2F)] at the beginning of the experiment and [6.22±2.7 L.min-1 (PAC) and 6.36±2.35 L.min-1 (mCO2F)] at 4 h after the experiment; however, they were highly correlated (r=0.939 and 0.908, P<0.001). The cardiac output determined by PiCCO and mCO2F method was also not significantly (P>0.05) different [6.05±2.49 L.min-1 (PiCCO) and 5.44±1.64 L.min-1 (mCO2F)] at the beginning of the experiment, and [6.17±2.04 L.min-1 (PiCCO) and 5.70±1.72 L.min-1 (mCO2F)] at 4 h after the experiment; however, they were highly correlated (r=0.776 and 0.832, P<0.001). Conclusion: The mCO2F method could accurately measure the cardiac output in mechanically ventilated patients without using any expensive equipment’s and invasive procedures. PMID:26064245

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  17. Stormy Course of a Huge Submitral Aneurysm Causing Low Cardiac Output State

    PubMed Central

    Gokhroo, Rajendra Kumar; Kishor, Kamal; Ranwa, Bhanwar

    2016-01-01

    Submitral aneurysm is a rare structural abnormality of congenital or acquired aetiology. Most reported cases are from Africa. Unless promptly treated surgically this condition is invariably fatal. We report a case of a young Indian male who presented with dyspnea of recent onset, diagnosed to have a massive submitral aneurysm causing low cardiac output and compression of cardiac structures. PMID:27081448

  18. Lithium dilution measurement of cardiac output and arterial pulse waveform analysis: an indicator dilution calibrated beat-by-beat system for continuous estimation of cardiac output.

    PubMed

    Jonas, Max M; Tanser, Suzie J

    2002-06-01

    Lithium dilution cardiac output (LiDCO trade mark; LiDCO, London, UK) is a minimally invasive indicator dilution technique for the measurement of cardiac output. It was primarily developed as a simple calibration for the PulseCO trade mark (LiDCO, London, UK) continuous arterial waveform analysis monitor. The technique is quick and simple, requiring only an arterial line and central or peripheral venous access. These lines would probably already have been inserted in critical care patients. A small dose of lithium chloride is injected as an intravenous bolus, and cardiac output is derived from the dilution curve generated by a lithium-sensitive electrode attached to the arterial line. Studies in humans and animals have shown good agreement compared with results obtained with other techniques, and the efficacy of LiDCO trade mark in pediatric patients has also been proven. Compared with thermodilution, lithium dilution showed closer agreement in clinical studies with electromagnetic flow measurement.PulseCO trade mark is a beat-to-beat cardiac output monitor that calculates stroke volume from the arterial pressure waveform using an autocorrelation algorithm. The algorithm is not dependent on waveform morphology, but, rather, it calculates nominal stroke volume from a pressure-volume transform of the entire waveform. The nominal stroke volume is converted to actual stroke volume by calibration of the algorithm with LiDCO trade mark. Initial studies indicate good fidelity, and the results from centers in the United States and the United Kingdom are extremely encouraging. The PulseCO trade mark monitor incorporates software for interpretation of the hemodynamic data generated and provides a real-time analysis of arterial pressure variations (ie, stroke volume variation, pulse pressure variation, and systolic pressure variation) as theoretical guides to intravascular and cardiac filling. PMID:12386506

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

    PubMed Central

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

    2006-01-01

    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 alternatives are available. Recently, a device offering uncalibrated CO measurement by arterial waveform analysis (COWave) was introduced. As far as this approach is concerned, however, the validity of the CO measurements obtained is utterly unclear. Therefore, the aim of this study was to compare the bias and the limits of agreement (LOAs) (two standard deviations) of COWave at four specified time points prior, during, and after coronary artery bypass graft (CABG) surgery with a simultaneous measurement of the gold standard COPAC and aortic transpulmonary thermodilution CO (COTranspulm). Methods Data from 30 patients were analysed during this prospective study. COPAC, COTranspulm, and COWave were determined in all patients at four different time points prior, during, and after CABG surgery. The COPAC and the COTranspulm were measured by triple injection of 10 ml of iced isotone sodium chloride solution into the central venous line of the PAC. Measurements of COWave were simultaneously taken at these time points. Results The overall correlation showed a Spearman correlation coefficient between COPAC and COWave of 0.53 (p < 0.01) and 0.84 (p < 0.01) for COPAC and COTranspulm. Bland-Altman analysis showed a mean bias and LOAs of 0.6 litres per minute and -2.2 to +3.4 litres per minute for COPAC versus COWave and -0.1 litres per minute and -1.8 to +1.6 litres per minute for COPAC versus COTranspulm. Conclusion Arterial waveform analysis with an uncalibrated algorithm COWave underestimated COPAC to a clinically relevant extent. The wide range of LOAs requires further evaluation. Better results might be achieved with an improved new algorithm. In contrast to this, we observed a better correlation of thermodilution COTranspulm and thermodilution COPAC measurements prior, during, and after CABG surgery. PMID:17118186

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

    PubMed

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

    1988-12-01

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

  1. Management of the Low Cardiac Output Syndrome Following Surgery for Congenital Heart Disease.

    PubMed

    Chandler, Heather K; Kirsch, Roxanne

    2016-01-01

    The purpose of this review is to discuss the management of the low cardiac output syndrome (LCOS) following surgery for congenital heart disease. The LCOS is a well-recognized, frequent post-operative complication with an accepted collection of hemodynamic and physiologic aberrations. Approximately 25% of children experience a decrease in cardiac index of less than 2 L/min/m2 within 6-18 hours after cardiac surgery. Post-operative strategies that may be used to manage patients as risk for or in a state of low cardiac output include the use of hemodynamic monitoring, enabling a timely and accurate assessment of cardiovascular function and tissue oxygenation; optimization of ventricular loading conditions; the judicious use of inotropic agents; an appreciation of and the utilization of positive pressure ventilation for circulatory support; and, in some circumstances, mechanical circulatory support. All interventions and strategies should culminate in improving the relationship between oxygen supply and demand, ensuring adequate tissue oxygenation. PMID:26585039

  2. [The interrelations of arterial pressure, cardiac output and coronary blood flow during orthostatic reactions].

    PubMed

    Osadchiĭ, L I; Balueva, T V; Sergeev, I V

    1989-08-01

    The influence of hypotension induced with orthostasis, upon cardiac output and coronary flow was studied in anesthetized cats. The body tilt to 15-60 degrees lowered the mean arterial pressure parallel with reduction of cardiac output. Under the tilt up to 30 degrees and 60 degrees, a significant difference was found in decrease of systolic but not diastolic pressures. The degree of cardiac output reduction was two-fold greater than the degree of diastolic pressure reduction. The findings suggest a participation of vascular constrictor responses in the forming of orthostatic reactions. The coronary flow decrease only began with the tilt up to 30 degrees. Its extent did not depend on the intensity of hypotension being, probably, the result of the reduction of the heart work. PMID:2612665

  3. Validation of a new spectrometer for noninvasive measurement of cardiac output

    NASA Astrophysics Data System (ADS)

    Baum, Marc M.; Kumar, Sasi; Moss, John A.; Wagner, Peter D.

    2004-07-01

    Acetylene is a blood-soluble gas and for many years its uptake rate during rebreathing tests has been used to calculate the flow rate of blood through the lungs (normally equal to cardiac output) as well as the volume of lung tissue. A new, portable, noninvasive instrument for cardiac output determination using the acetylene uptake method is described. The analyzer relies on nondispersive IR absorption spectroscopy as its principle of operation and is configured for extractive (side-stream) sampling. The instrument affords exceptionally fast (30 ms, 10%-90%, 90%-10%, at 500 mL min-1 flow rates), interference-free, simultaneous measurement of acetylene, sulfur hexafluoride (an insoluble reference gas used in the cardiac output calculation), and carbon dioxide (to determine alveolar ventilation), with good (typically ±2% full-scale) signal-to-noise ratios. Comparison tests with a mass spectrometer using serially diluted calibration gas samples gave excellent (R2>0.99) correlation for all three gases, validating the IR system's linearity and accuracy. A similar level of agreement between the devices also was observed during human subject C2H2 uptake tests (at rest and under incremental levels of exercise), with the instruments sampling a common extracted gas stream. Cardiac output measurements by both instruments were statistically equivalent from rest to 90% of maximal oxygen consumption; the physiological validity of the measurements was confirmed by the expected linear relationship between cardiac output and oxygen consumption, with both the slope and intercept in the published range. These results indicate that the portable, low-cost, rugged prototype analyzer discussed here is suitable for measuring cardiac output noninvasively in a point-of-care setting.

  4. Continuous cardiac output measurement - Aspects of Doppler frequency analysis

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  5. Pulmonary arterial hypertension combined with a high cardiac output state: Three remarkable cases

    PubMed Central

    Spruijt, Onno A.; Bogaard, Harm-Jan; Vonk-Noordegraaf, Anton

    2013-01-01

    A congenital extrahepatic portosystemic venous shunt (CEPVS), also known as an Abernethy malformation, is a rare cause of pulmonary arterial hypertension (PAH). In this case series, we describe three male patients of 30, 23, and 27 years of age with PAH due to a CEPVS. In all three patients, a right heart catheterization revealed a high cardiac output. The aim of this case series is to make pulmonary hypertension physicians aware of the possibility of a CEPVS when PAH is accompanied with a high cardiac output state. PMID:24015348

  6. Efficacy of Goal-Directed Therapy Using Bioreactance Cardiac Output Monitoring after Valvular Heart Surgery

    PubMed Central

    Lee, Sak; Lee, Seung Hyun; Chang, Byung-Chul

    2015-01-01

    Purpose We compared the efficacy of postoperative hemodynamic goal-directed therapy (GDT) using a pulmonary artery catheter (PAC) and bioreactance-based noninvasive cardiac output monitoring (NICOM) in patients with atrial fibrillation undergoing valvular heart surgery. Materials and Methods Fifty eight patients were randomized into two groups of GDT with common goals to maintain a mean arterial pressure of 60-80 mm Hg and cardiac index ?2 L/min/m2: the PAC group (n=29), based on pulmonary capillary wedge pressure, and the NICOM group (n=29), based on changes in stroke volume index after passive leg raising. The primary efficacy variable was length of hospital stay. Secondary efficacy variables included resource utilization including vasopressor and inotropic requirement, fluid balance, and major morbidity endpoints. Results Patient characteristics and operative data were similar between the groups, except that significantly more patients underwent double valve replacement in the NICOM group. The lengths of hospital stay were not different between the two groups (12.24.8 days vs. 10.84.0 days, p=0.239). Numbers of patients requiring epinephrine (5 vs. 0, p=0.019) and ventilator care >24 h (6 vs. 1, p=0.044) were significantly higher in the PAC group. The PAC group also required significantly larger amounts of colloid (1652519 mL vs. 11430463 mL, p=0.004). Conclusion NICOM-based postoperative hemodynamic GDT showed promising results in patients with atrial fibrillation undergoing valvular heart surgery in terms of resource utilization. PMID:26069111

  7. The influence of high-velocity circuit resistance training on VO2max and cardiac output.

    PubMed

    Petersen, S R; Haennel, R G; Kappagoda, C T; Belcastro, A N; Reid, D C; Wenger, H A; Quinney, H A

    1989-09-01

    In order to investigate the influence of high-velocity circuit resistance training on maximal aerobic power, maximal stroke volume and cardiac output, and blood lactate removal during recovery, 16 habitually active males were blocked on initial VO2max into either training or control groups. The training group completed two (weeks 1 and 2) or three (weeks 3-6) circuits of 10 variable-resistance hydraulic exercise stations at an exercise: relief ratio of 1:2 on alternate days over six weeks. Angular velocities of movement were maintained at approximately 3.1 rad.s-1. Following training, the VO2max was increased (p less than .01) from 4.32 to 4.68 1.min-1. Maximal stroke volume was increased (p less than .05) from 120 to 129 mL and heart rate response to an absolute submaximal exercise load was decreased (p less than .05) from 153 to 146 beats.min-1. As well, enhanced (p less than .01) removal of lactate from the blood was observed during recovery from exhausting exercise. No changes were observed for control subjects. These results indicate that positive alterations in aerobic and cardiovascular function may be achieved consequent to high-velocity circuit resistance training. PMID:2819610

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

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

    PubMed

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

    2011-10-01

    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

  10. Continuous minimally invasive peri-operative monitoring of cardiac output by pulmonary capnotracking: comparison with thermodilution and transesophageal echocardiography.

    PubMed

    Peyton, Philip J

    2012-04-01

    A number of technologies are available for minimally-invasive cardiac output measurement in patients during surgery but remain little used. A system has been developed based on CO(2) elimination (VCO(2)) by the lungs for use in ventilated patients, which can be fully integrated into a modern anesthesia/monitoring platform, and provides semi-automated, continuous breath-by-breath cardiac output monitoring. A prototype measurement system was constructed to measure VCO(2) and end-tidal CO(2) concentration with each breath. A baseline measurement of non-shunt cardiac output was made during a brief change in ventilator rate, according to the differential CO(2) Fick approach. Continuous breath-by-breath monitoring of cardiac output was then performed from measurement of VCO(2), using a derivation of the Fick equation applied to pulmonary CO(2) elimination. Automated recalibration was done periodically and data was processed and cardiac output displayed in real time. Measurements were compared with simultaneous measurements by bolus thermodilution in 77 patients undergoing cardiac surgery or liver transplantation. Overall mean bias [sd] for agreement in cardiac output measurement was -0.1 [1.2] L/min, percentage error +44.2%, r = 0.92. Concordance in measurement of changes of at least 15% in cardiac output was 80%. The method followed sudden changes in cardiac output due to arrythmias and run onto cardiopulmonary bypass in real time. The accuracy and precision were comparable to other clinical techniques. The method is relatively seamless and largely automated and has potential for continuous, cardiac output monitoring in ventilated patients during anesthesia and critical care. PMID:22350312

  11. Peripartum cardiomyopathy: postpartum decompensation and use of non-invasive cardiac output monitoring.

    PubMed

    Lorello, G; Cubillos, J; McDonald, M; Balki, M

    2014-02-01

    The utility of a non-invasive cardiac output monitor (NICOM™) in guiding the peripartum management and identification of postpartum complications in a patient with severe peripartum cardiomyopathy is reported. A 31-year-old nulliparous woman at 35 weeks of gestation presented with a three-week history of worsening dyspnea and progressive functional deterioration. A transthoracic echocardiogram showed severe left ventricular systolic dysfunction with an ejection fraction <20%. Cardiac status was monitored using NICOM™ during labor and delivery. The baseline values were: cardiac output 5.3 L/min, total peripheral resistance 1549 dynes.sec/cm(5), stroke volume 42.1 mL and stroke volume variation 18%. She received early epidural analgesia during labor, titrated slowly with a loading dose of 0.0625% bupivacaine 10 mL and fentanyl 25 μg, followed by patient-controlled epidural analgesia (0.0625% bupivacaine with fentanyl 2 μg/mL, infusion at 10 mL/h, bolus dose 5 mL and lockout interval 10 min). After epidural drug administration, total peripheral resistance decreased, cardiac output increased, and satisfactory analgesia was obtained. She had an uneventful vaginal delivery with a forceps-assisted second stage after prophylactic administration of furosemide 20 mg. NICOM™ was discontinued after delivery. Fifteen hours post-delivery, the patient developed cardiogenic shock, which resolved after aggressive therapy with inotropes and furosemide. NICOM™ can be used to guide treatment during labor and delivery in patients with critical peripartum cardiomyopathy. We suggest that use of NICOM™ be extended into the postpartum period to detect signs of cardiac decompensation in such patients. PMID:24360329

  12. Cardiac output and tissue blood flow in the abalone, Haliotis cracherodii (Mollusca, Gastropoda).

    PubMed

    Jorgensen, D D; Ware, S K; Redmond, J R

    1984-09-01

    Little is known about the characteristics of hemolymph (blood) flow in animals with open circulatory systems. We measured cardiac output and blood flow to specific tissues in the black abalone, Haliotis cracherodii, a gastropod mollusk. The use of thermodilution allowed us to make repeated measurements of cardiac output and cardiac stroke volume over relatively short time intervals (5-10 heart beats) in resting, unrestrained abalone while disturbing the animals minimally. Anatomical studies of the abalone circulation showed that the arterial system terminated in small diameter (approaching 10-20 micron in some cases) lacunar tissue spaces. Because of this, we used radioactive microspheres (which must be trapped in the tissue vasculature) to measure blood flow rates to selected tissues. The major findings of our study were that 1) cardiac output in the black abalone ranged from about 100 to 150 ml X kg-1 X min-1, and was highly correlated with body size; 2) weight-specific cardiac stroke volume was about 5 ml X kg-1, considerably larger than that of a mammal; 3) tissue blood flow rates ranged from 10 ml X 100 g-1 X min-1 (foot muscle) to 80 ml X 100 g-1 X min-1 (nephridial tissue), similar to typical tissue blood flow rates in mammals. Our data suggest that the blood in the abalone is directed to the tissues not in proportion to percent total body weight the tissues represent (as might be expected in an open vascular system), but apparently in proportion to tissue metabolic rate. PMID:6502086

  13. Dynamic asymmetries of cardiac output transients in response to muscular exercise in man.

    PubMed Central

    Yoshida, T; Whipp, B J

    1994-01-01

    1. We determined the kinetics of cardiac output (Q) with respect to oxygen uptake (VO2) at the on- and off-transients of constant-load exercise. Six subjects performed constant-load exercise which consisted of 5 min rest, 5 min one-legged pedalling at 50 W and a 5 min recovery period. 2. The transient responses were characterized by first-order kinetics. There was no significant difference between the time constants for VO2 (tau VO2) at the on- (33.9 +/- 3.5 s, mean +/- S.E.M.) and off-transient (37.2 +/- 2.9 s). The time constant for Q (tau Q, 29.4 +/- 3.2 s) was consistently shorter than tau VO2 at the on-transient. However, tau Q was appreciably longer at the off-transient (44.3 +/- 3.6 s) than the on-transient. 3. The results support the contention that the time constant for the on-transient of Q is appreciably faster than that for VO2 and hence there seems little justification for the notion that the time constants for the kinetics of VO2 are determined by the limitations of blood flow in the transient. The asymmetry of Q kinetics, with the off-transient tau Q being appreciably slower than the on-transient tau Q, serves to maintain a sufficiently high oxygen flow to the muscle during recovery from exercise at a time when the muscle oxygen uptake remains high. PMID:7869250

  14. Postnatal changes in cardiac output and haemorrheology in normal neonates born at full term.

    PubMed Central

    Mandelbaum, V H; Alverson, D C; Kirchgessner, A; Linderkamp, O

    1991-01-01

    Circulatory adaptation was studied serially in 11 healthy term neonates on days 1, 3, and 5 by cross sectional and pulsed Doppler echocardiography. Changes in the determinants of blood viscosity (packed cell volume, plasma viscosity, red cell aggregation, and red cell deformability) were studied on day 1 and day 5. There was a 27% increase in the cardiac output as a result of increasing stroke volume, whereas heart rate did not change significantly. Mean blood pressure increased by nearly the same extent as cardiac output (21%), so that the overall resistance remained unchanged. Packed cell volume, red cell aggregation, and red cell deformability did not change significantly during the first five postnatal days. Plasma viscosity rose significantly (by 12%) so that whole blood viscosity increased during that period. As there was no change in overall systemic vascular resistance the vascular hindrance--calculated as the ratio of resistance: blood viscosity--decreased, thereby indicating vasodilation. PMID:2025030

  15. Constant infusion transpulmonary thermodilution for the assessment of cardiac output in exercising humans.

    PubMed

    Calbet, J A L; Mortensen, S P; Munch, G D W; Curtelin, D; Boushel, R

    2016-05-01

    To determine the accuracy and precision of constant infusion transpulmonary thermodilution cardiac output (CITT-Q) assessment during exercise in humans, using indocyanine green (ICG) dilution and bolus transpulmonary thermodilution (BTD) as reference methods, cardiac output (Q) was determined at rest and during incremental one- and two-legged pedaling on a cycle ergometer, and combined arm cranking with leg pedaling to exhaustion in 15 healthy men. Continuous infusions of iced saline in the femoral vein (n = 41) or simultaneously in the femoral and axillary (n = 66) veins with determination of temperature in the femoral artery were used for CITT-Q assessment. CITT-Q was linearly related to ICG-Q (r = 0.82, CITT-Q = 0.876 × ICG-Q + 3.638, P < 0.001; limits of agreement ranging from -1.43 to 3.07 L/min) and BTD-Q (r = 0.91, CITT-Q = 0.822 × BTD + 4.481 L/min, P < 0.001; limits of agreement ranging from -1.01 to 2.63 L/min). Compared with ICG-Q and BTD-Q, CITT-Q overestimated cardiac output by 1.6 L/min (≈ 10% of the mean ICG and BTD-Q values, P < 0.05). For Q between 20 and 28 L/min, we estimated an overestimation < 5%. The coefficient of variation of 23 repeated CITT-Q measurements was 6.0% (CI: 6.1-11.1%). In conclusion, cardiac output can be precisely and accurately determined with constant infusion transpulmonary thermodilution in exercising humans. PMID:25919489

  16. Levosimendan in a neonate with severe coarctation of aorta and low cardiac output syndrome.

    PubMed

    Boegli, Yann Olivier; Gioanni, Simone; van Steenberghe, Mathieu; Pouard, Philippe

    2013-01-01

    We report successful use of levosimendan after failed balloon angioplasty in a critically ill neonate with coarctation of aorta (CoA) and severe low cardiac output syndrome (LCOS). Treatment with levosimendan improved left heart function, and decreased lactate and brain natriuretic peptide levels. To our knowledge, this is the first report on the safe and successful use of levosimendan in the management of LCOS due to severe CoA in a neonate awaiting surgical repair. PMID:23816677

  17. Validation and application of single breath cardiac output determinations in man

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    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.

  18. Validation of a new method to measure cardiac output during extracorporeal detoxification.

    PubMed

    Nikiforov, Y V; Kisluchine, V V; Chaus, N I

    1996-01-01

    Cardiac output was measured in 11 patients during extra-corporeal detoxification after open heart surgery. All patients were mechanically ventilated and had pulmonary artery catheters for cardiac output (COT) measured by thermodilution. A sensor on the arterial side of the extracorporeal circulation measured flow and sound velocity transients. Injections of 2-5 ml 0.9% saline at 37 degrees C into the arterial line upstream of the sensor permitted its calibration; 10-20 ml of the same solution was injected intravenously or into the venous dialysis injection port, and cardiac output (COUD) was calculated by the ultrasound velocity dilution technique. COT was measured within 5 min of the ultrasound dilution measurement. CO was in the range of 2-8 L/m. The regression equation was COUD = 1.09 x COT-0.32 (r = 0.97, n = 31). These data suggest agreement between the ultrasound dilution technique and thermodilution. Ultrasound dilution is preferable in patients undergoing extracorporeal detoxification when pulmonary artery catheterization is not required or dangerous. PMID:8945017

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

    PubMed Central

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

    2012-01-01

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

  20. The effects of long-term aerobic exercise on cardiac structure, stroke volume of the left ventricle, and cardiac output.

    PubMed

    Lee, Bo-Ae; Oh, Deuk-Ja

    2016-02-01

    The purpose of this study is to investigate the effect of the long-term aerobic exercises on cardiac structure, left ventricular stroke volume, and cardiac output. To achieve the purpose of the study, a total of 22 volunteers-including 10 people who have continued regular exercises and 12 people as the control group-were selected as subjects. With regard to data processing, the IBM SPSS Statistics ver. 21.0 was used to calculate the mean and standard deviation, and the difference of the means between the groups was verified through an independent t-test. As a result, there were significant differences between groups in the left ventricular end-diastolic internal dimension, left ventricular end-systolic internal dimension, left ventricular end-diastolic septum thickness. There were significant differences between groups in left ventricular end-diastolic volume, left ventricular mass, and left ventricular mass index per body surface area. However, in cardiac function, only left ventricular stroke volume showed a significant difference between groups. PMID:26933658

  1. The effects of long-term aerobic exercise on cardiac structure, stroke volume of the left ventricle, and cardiac output

    PubMed Central

    Lee, Bo-Ae; Oh, Deuk-Ja

    2016-01-01

    The purpose of this study is to investigate the effect of the long-term aerobic exercises on cardiac structure, left ventricular stroke volume, and cardiac output. To achieve the purpose of the study, a total of 22 volunteers—including 10 people who have continued regular exercises and 12 people as the control group—were selected as subjects. With regard to data processing, the IBM SPSS Statistics ver. 21.0 was used to calculate the mean and standard deviation, and the difference of the means between the groups was verified through an independent t-test. As a result, there were significant differences between groups in the left ventricular end-diastolic internal dimension, left ventricular end-systolic internal dimension, left ventricular end-diastolic septum thickness. There were significant differences between groups in left ventricular end-diastolic volume, left ventricular mass, and left ventricular mass index per body surface area. However, in cardiac function, only left ventricular stroke volume showed a significant difference between groups. PMID:26933658

  2. Embryonic and adult-derived resident cardiac macrophages are maintained through distinct mechanisms at steady state and during inflammation.

    PubMed

    Epelman, Slava; Lavine, Kory J; Beaudin, Anna E; Sojka, Dorothy K; Carrero, Javier A; Calderon, Boris; Brija, Thaddeus; Gautier, Emmanuel L; Ivanov, Stoyan; Satpathy, Ansuman T; Schilling, Joel D; Schwendener, Reto; Sergin, Ismail; Razani, Babak; Forsberg, E Camilla; Yokoyama, Wayne M; Unanue, Emil R; Colonna, Marco; Randolph, Gwendalyn J; Mann, Douglas L

    2014-01-16

    Cardiac macrophages are crucial for tissue repair after cardiac injury but are not well characterized. Here we identify four populations of cardiac macrophages. At steady state, resident macrophages were primarily maintained through local proliferation. However, after macrophage depletion or during cardiac inflammation, Ly6c(hi) monocytes contributed to all four macrophage populations, whereas resident macrophages also expanded numerically through proliferation. Genetic fate mapping revealed that yolk-sac and fetal monocyte progenitors gave rise to the majority of cardiac macrophages, and the heart was among a minority of organs in which substantial numbers of yolk-sac macrophages persisted in adulthood. CCR2 expression and dependence distinguished cardiac macrophages of adult monocyte versus embryonic origin. Transcriptional and functional data revealed that monocyte-derived macrophages coordinate cardiac inflammation, while playing redundant but lesser roles in antigen sampling and efferocytosis. These data highlight the presence of multiple cardiac macrophage subsets, with different functions, origins, and strategies to regulate compartment size. PMID:24439267

  3. LRRC10 is required to maintain cardiac function in response to pressure overload.

    PubMed

    Brody, Matthew J; Feng, Li; Grimes, Adrian C; Hacker, Timothy A; Olson, Timothy M; Kamp, Timothy J; Balijepalli, Ravi C; Lee, Youngsook

    2016-01-15

    We previously reported that the cardiomyocyte-specific leucine-rich repeat containing protein (LRRC)10 has critical functions in the mammalian heart. In the present study, we tested the role of LRRC10 in the response of the heart to biomechanical stress by performing transverse aortic constriction on Lrrc10-null (Lrrc10(-/-)) mice. Mild pressure overload induced severe cardiac dysfunction and ventricular dilation in Lrrc10(-/-) mice compared with control mice. In addition to dilation and cardiomyopathy, Lrrc10(-/-) mice showed a pronounced increase in heart weight with pressure overload stimulation and a more dramatic loss of cardiac ventricular performance, collectively suggesting that the absence of LRRC10 renders the heart more disease prone with greater hypertrophy and structural remodeling, although rates of cardiac fibrosis and myocyte dropout were not different from control mice. Lrrc10(-/-) cardiomyocytes also exhibited reduced contractility in response to β-adrenergic stimulation, consistent with loss of cardiac ventricular performance after pressure overload. We have previously shown that LRRC10 interacts with actin in the heart. Here, we show that His(150) of LRRC10 was required for an interaction with actin, and this interaction was reduced after pressure overload, suggesting an integral role for LRRC10 in the response of the heart to mechanical stress. Importantly, these experiments demonstrated that LRRC10 is required to maintain cardiac performance in response to pressure overload and suggest that dysregulated expression or mutation of LRRC10 may greatly sensitize human patients to more severe cardiac disease in conditions such as chronic hypertension or aortic stenosis. PMID:26608339

  4. Cardiac Remodeling in Fish: Strategies to Maintain Heart Function during Temperature Change

    PubMed Central

    Klaiman, Jordan M.; Fenna, Andrew J.; Shiels, Holly A.; Macri, Joseph; Gillis, Todd E.

    2011-01-01

    Rainbow trout remain active in waters that seasonally change between 4°C and 20°C. To explore how these fish are able to maintain cardiac function over this temperature range we characterized changes in cardiac morphology, contractile function, and the expression of contractile proteins in trout following acclimation to 4°C (cold), 12°C (control), and 17°C (warm). The relative ventricular mass (RVM) of the cold acclimated male fish was significantly greater than that of males in the control group. In addition, the compact myocardium of the cold acclimated male hearts was thinner compared to controls while the amount of spongy myocardium was found to have increased. Cold acclimation also caused an increase in connective tissue content, as well as muscle bundle area in the spongy myocardium of the male fish. Conversely, warm acclimation of male fish caused an increase in the thickness of the compact myocardium and a decrease in the amount of spongy myocardium. There was also a decrease in connective tissue content in both myocardial layers. In contrast, there was no change in the RVM or connective tissue content in the hearts of female trout with warm or cold acclimation. Cold acclimation also caused a 50% increase in the maximal rate of cardiac AM Mg2+-ATPase but did not influence the Ca2+ sensitivity of this enzyme. To identify a mechanism for this change we utilized two-dimensional difference gel electrophoresis to characterize changes in the cardiac contractile proteins. Cold acclimation caused subtle changes in the phosphorylation state of the slow skeletal isoform of troponin T found in the heart, as well as of myosin binding protein C. These results demonstrate that acclimation of trout to warm and cold temperatures has opposing effects on cardiac morphology and tissue composition and that this results in distinct warm and cold cardiac phenotypes. PMID:21915331

  5. Measurement of cardiac output by automated single-breath technique, and comparison with thermodilution and Fick methods in patients with cardiac disease.

    PubMed

    Zenger, M R; Brenner, M; Haruno, M; Mahon, D; Wilson, A F

    1993-01-01

    Accurate noninvasive methods are needed for determination of cardiac output. Current methods are generally complex or may be unreliable. A previously described method, based on absorption of acetylene gas during a constant exhalation that enables calculation of cardiac output by estimating pulmonary capillary circulation, is incorporated in a new, automated commercial product (SensorMedics 2200). In this study, cardiac output by single-breath acetylene blood flow measured with this device was compared with the standard thermodilution and direct Fick methods in 20 patients undergoing cardiac or pulmonary artery catheterization. Patients inhaled test gas mixture to total lung capacity and exhaled at a constant rate through an adjustable resistor. Lung volumes and noninvasive acetylene blood flow value were calculated automatically. Correlation between the automated single-breath technique and both thermodilution and Fick cardiac output determinations was very high (correlation coefficients were 0.90 and 0.92, respectively), regression slopes were close to identity (0.98 and 0.90), and bias (-0.39 and -0.79 liter/min) and precision (0.94 and 1.02) were good; when shunt correction was applied, bias was reduced to 0.06 and 0.35 liter/min, respectively. Rapid, accurate, noninvasive measurement of cardiac output was easily obtained using the automated device. This technique may have a wide applicability for noninvasive evaluation of patients with cardiac disease and for monitoring effects of therapeutic interventions. PMID:8420224

  6. Initial Observations of the Effects of Calcium Chloride Infusions in Pediatric Patients with Low Cardiac Output.

    PubMed

    Averin, Konstantin; Villa, Chet; Krawczeski, Catherine D; Pratt, Jesse; King, Eileen; Jefferies, John L; Nelson, David P; Cooper, David S; Ryan, Thomas D; Sawyer, Jaclyn; Towbin, Jeffrey A; Lorts, Angela

    2016-03-01

    Myocardial contractility and relaxation are highly dependent on calcium homeostasis. Immature myocardium, as in pediatric patients, is thought to be more dependent on extracellular calcium for optimal function. For this reason, intravenous calcium chloride infusions may improve myocardial function in the pediatric patient. The objectives of this study were to report the hemodynamic changes seen after administration of continuous calcium chloride to critically ill children. We retrospectively identified pediatric patients (newborn to 17 years old) with hemodynamic instability admitted to the cardiac ICU between May 2011 and May 2012 who received a continuous infusion of calcium chloride. The primary outcome was improvement in cardiac output, assessed by arterial-mixed venous oxygen saturation (A-V) difference. Sixty-eight patients, mean age 0.87 ± 2.67 years, received a total of 116 calcium infusions. Calcium chloride infusions resulted in significant improvements in primary and secondary measures of cardiac output at 2 and 6 h. Six hours after calcium initiation, A-V oxygen saturation difference decreased by 7.4 % (32.6 ± 2.1 to 25.2 ± 2.0 %, p < 0.001), rSO2 increased by 5.5 % (63.1 vs 68.6 %, p < 0.001), and serum lactate decreased by 0.9 mmol/l (3.3 vs 2.4 mmol/l, p < 0.001) with no change in HR (149.1 vs 145.6 bpm p = 0.07). Urine output increased 0.66 ml/kg/h in the 8-h period after calcium initiation when compared to pre-initiation (p = 0.003). Neonates had the strongest evidence of effectiveness with other age groups trending toward significance. Calcium chloride infusions improve markers of cardiac output in a heterogenous group of pediatric patients in a cardiac ICU. Neonates appear to derive the most benefit from utilization of these infusions. PMID:26687150

  7. Caveolae protect endothelial cells from membrane rupture during increased cardiac output

    PubMed Central

    Cheng, Jade P.X.; Mendoza-Topaz, Carolina; Howard, Gillian; Chadwick, Jessica; Shvets, Elena; Cowburn, Andrew S.; Dunmore, Benjamin J.; Crosby, Alexi; Morrell, Nicholas W.

    2015-01-01

    Caveolae are strikingly abundant in endothelial cells, yet the physiological functions of caveolae in endothelium and other tissues remain incompletely understood. Previous studies suggest a mechanoprotective role, but whether this is relevant under the mechanical forces experienced by endothelial cells in vivo is unclear. In this study we have sought to determine whether endothelial caveolae disassemble under increased hemodynamic forces, and whether caveolae help prevent acute rupture of the plasma membrane under these conditions. Experiments in cultured cells established biochemical assays for disassembly of caveolar protein complexes, and assays for acute loss of plasma membrane integrity. In vivo, we demonstrate that caveolae in endothelial cells of the lung and cardiac muscle disassemble in response to acute increases in cardiac output. Electron microscopy and two-photon imaging reveal that the plasma membrane of microvascular endothelial cells in caveolin 1−/− mice is much more susceptible to acute rupture when cardiac output is increased. These data imply that mechanoprotection through disassembly of caveolae is important for endothelial function in vivo. PMID:26459598

  8. The Prognostic Value of Peak Cardiac Power Output in Chinese Patients with Chronic Heart Failure

    PubMed Central

    Ma, Wenlin; Gong, Zhu; Ni, Yi; Zhang, Xiaoyu; Xu, Wenjun; Jiang, Jinfa; Che, Lin; Xu, Jiahong; Yan, Wenwen; Zhou, Lin; Li, Guanghe; Zhang, Qiping; Wang, Lemin

    2016-01-01

    Background Cardiopulmonary exercise testing has been widely used to risk stratify patients with chronic heart failure (CHF). Peak oxygen consumption (peakVO2) was regarded as a powerful predictor of survival, as it is a surrogate for peak cardiac output (CO), which by most is considered the “true” measure of heart failure. Therefore, it is reasonable to hypothesize that CO is an even stronger predictor than peak VO2. The present study is aimed to investigate the prognostic value of peak cardiac power output (peak CPO) in comparison with peakVO2 in Chinese patients with CHF. Methods Participants provided written informed consent to participate in this study. Totally 129 patients with CHF underwent symptom-limited cardiopulmonary exercise testing (CPET), with mean age 59.1±11.4 years, 87.6% male, 57.4% ischemic etiology, body mass index (BMI) 24.7±3.7 kg/m2 and LVEF 38±9%. CO was measured using an inert gas rebreathing method. The primary endpoints are cardiac deaths. Results Over median 33.7-month follow-up, 19 cardiac deaths were reported. Among peak VO2,VE/VCO2 slope and Peak CPO, their area under ROC were 0.64, 0.67, 0.68, respectively (Ρ<0.05).The optimal thresholds for predicting cardiac deaths were peak VO2≤13.4 ml.kg-1.min-1, and VE/VCO2 slope≥39.3 and peak CPO≤ 1.1 respectively by ROC analysis. Finally, in patients with a peak VO2≤13.4 ml.kg-1.min-1 those with peak CPO>1.1W had better survival than those with peak CPO ≤ 1.1W. However, by multivariate analysis adjusted for age, sex, BMI, resting heart rate, LVMI, LVEF, Peak CPO was not an independent predictor of cardiac deaths (P> 0.05). Conclusions Peak CPO was not a predictor of cardiac death in Chinese CHF patients. PMID:26808510

  9. Non-invasive cardiac output monitoring for cesarean delivery under epidural anesthesia in a patient with Marfan syndrome and cardiomyopathy.

    PubMed

    Beaudry, S; Pick, J; Heerdt, P M

    2016-02-01

    Maternal cardiac output and stroke volume increase significantly at the time of cesarean delivery. Parturients with baseline myocardial dysfunction are at increased risk of cardiovascular decompensation in the peripartum period and close hemodynamic monitoring is warranted. We report our use of intraoperative non-invasive cardiac output monitoring during cesarean delivery under epidural anesthesia in a 24-year-old woman with dilated cardiomyopathy secondary to Marfan syndrome, aortic arch, aortic valve and mitral valve replacements and a left ventricular ejection fraction of 37%. Three distinct hemodynamic trends were noted. After achieving adequate surgical anesthesia with 2% lidocaine 20mL, cardiac output and stroke volume rose for approximately 20min from baseline values of 6.3L/min and 69mL, respectively, to 9L/min and 107mL. Values subsequently trended down and remained depressed for nearly 20min following delivery. The lack of immediate post-delivery increases in both cardiac output and stroke volume were attributed to acute blood loss, intravascular volume depletion from fluid restriction, and slow infusion of oxytocin. By the end of surgery, cardiac output and stroke volume ultimately increased by 66% and 84% of baseline values, respectively. Systemic blood pressure, heart rate and cardiac output did not appear to correlate despite the use of phenylephrine to manage hypotension. The patient remained hemodynamically stable with no evidence of acute volume overload. PMID:26718697

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  11. Predictors of low cardiac output syndrome after isolated coronary artery bypass grafting.

    PubMed

    Ding, WenJun; Ji, Qiang; Shi, YunQing; Ma, RunHua

    2015-01-01

    Low cardiac output syndrome (LCOS) is one of the most important complications following coronary artery bypass grafting (CABG) and results in higher morbidity and mortality. However, few reports have focused on the predictors of LCOS following CABG. This study aimed to evaluate the predictors of LCOS following isolated CABG through the review of 1524 consecutive well-documented patients in a single center, retrospective trial.The relevant preoperative and intraoperative data of patients with complete information from medical records undergoing isolated CABG from January 2010 to December 2013 in our center were investigated and retrospectively analyzed. LCOS was considered when the following criteria were met: signs of impairment of body perfusion and need for inotropic support with vasoactive drugs or mechanical circulatory support with an intra-aortic balloon pump to maintain systolic blood pressure greater than 90 mmHg.LCOS developed in 205 patients following CABG, accounting for 13.5% of the total population. The in-hospital mortality in the LCOS group was significantly higher than that in the non-LCOS group (25.4% versus 1.8%, P < 0.0001). In addition to the length of ICU stay and postoperative hospital stay, LCOS was correlated with negative cerebral, respiratory and renal outcomes. Through univariate analysis and then logistic regression analysis, the predictors of LCOS following CABG included older age (age > 65 years) (OR = 1.85, 95%CI 1.27-3.76), impaired left ventricular function (OR = 2.05, 95%CI 1.53-4.54), on-pump CABG (OR = 2.16, 95%CI 1.53-4.86), emergent CPB (OR = 9.15, 95%CI 3.84-16.49), and incomplete revascularization (OR = 2.62, 95%CI 1.79-5.15).LCOS following isolated CABG caused higher mortality, higher rates of morbidity, and longer ICU and postoperative hospital stays. Older age, impaired left ventricular function, on-pump CABG, emergent CPB, and incomplete revascularization were identified as 5 predictors of LCOS following isolated CABG surgery. PMID:25740396

  12. HDL Mimetic Peptide Administration Improves Left Ventricular Filling and Cardiac output in Lipopolysaccharide-Treated Rats

    PubMed Central

    Datta, Geeta; Gupta, Himanshu; Zhang, Zhenghao; Mayakonda, Palgunachari; Anantharamaiah, G.M.; White, C. Roger

    2012-01-01

    Aims Cardiac dysfunction is a complication of sepsis and contributes to morbidity and mortality. Since raising plasma apolipoprotein (apo) A-I and high density lipoprotein (HDL) concentration reduces sepsis complications, we tested the hypothesis that the apoA-I mimetic peptide 4F confers similar protective effects in rats treated with lipopolysaccharide (LPS). Methods and results Male Sprague-Dawley (SD) rats were randomized to receive saline vehicle (n=13), LPS (10 mg/kg: n=16) or LPS plus 4F (10 mg/kg each: n=13) by intraperitoneal injection. Plasma cytokine and chemokine levels were significantly elevated 24 hrs after LPS administration. Echocardiographic studies revealed changes in cardiac dimensions that resulted in a reduction in left ventricular end-diastolic volume (LVEDV), stroke volume (SV) and cardiac output (CO) 24 hrs after LPS administration. 4F treatment reduced plasma levels of inflammatory mediators and increased LV filling, resulting in improved cardiac performance. Chromatographic separation of lipoproteins from plasma of vehicle, LPS and LPS+4F rats revealed similar profiles. Further analyses showed that LPS treatment reduced the agarose electrophoretic mobility of isolated HDL fractions. HDL-associated proteins were characterized by SDSPAGE and mass spectrometry. ApoA-I and apoA-IV were reduced while apoE content was increased in LPStreated rats. 4F treatment in vivo attenuated changes in HDL-associated apolipoproteins and increased the electrophoretic mobility of the particle. Conclusions The ability of 4F to reduce inflammation and improve cardiac performance in LPS-treated rats may be due to its capacity to neutralize endotoxin and prevent adverse changes in HDL composition and function. PMID:23227448

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  14. Cardiac output and vasodilation in the vasovagal response: An analysis of the classic papers.

    PubMed

    Wieling, Wouter; Jardine, David L; de Lange, Frederik J; Brignole, Michele; Nielsen, Henning B; Stewart, Julian; Sutton, Richard

    2016-03-01

    The simple faint is secondary to hypotension and bradycardia resulting in transient loss of consciousness. According to Ohm's law applied to the circulation, BP = SVR × CO, hypotension can result from a decrease in systemic vascular resistance (SVR), cardiac output (CO), or both. It is important to understand that when blood pressure (BP) is falling, SVR and CO do not change reciprocally as they do in the steady state. In 1932, Lewis, assuming that decreased SVR alone accounted for hypotension, defined "the vasovagal response" along pathophysiologic lines to denote the association of vasodilation with vagal-induced bradycardia in simple faint. Studies performed by Barcroft and Sharpey-Schafer between 1940 and 1950 used volume-based plethysmography to demonstrate major forearm vasodilation during extreme hypotension and concluded that the main mechanism for hypotension was vasodilation. Plethysmographic measurements were intermittent and not frequent enough to capture rapid changes in blood flow during progressive hypotension. However, later investigations by Weissler, Murray, and Stevens performed between 1950 and 1970 used invasive beat-to-beat BP measurements and more frequent measurements of CO using the Fick principle. They demonstrated that CO significantly fell before syncope, and little vasodilation occurred until very late in the vasovagal reaction Thus, since the 1970s, decreasing cardiac output rather than vasodilation has been regarded as the principal mechanism for the hypotension of vasovagal syncope. PMID:26598322

  15. Haemoglobin concentration and linear cardiac output, peripheral resistance, and oxygen transport.

    PubMed Central

    Daniel, M K; Bennett, B; Dawson, A A; Rawles, J M

    1986-01-01

    Increasing the haemoglobin concentration results in increased oxygen transport at the cost of increased blood viscosity. This suggested the concept of an optimum packed cell volume for maximising oxygen transport and a study was therefore conducted seeking supportive evidence. Linear cardiac output was measured as minute distance by Doppler ultrasound in 40 patients with haemopoietic disorders who had stable haemoglobin concentrations ranging from 30 to 200 g/l. The correlation between haemoglobin concentration and minute distance (r = -0.45; p less than 0.01) was negative, and correlations between haemoglobin concentration and mean blood pressure (r = 0.66; p less than 0.001) and haemoglobin concentration and peripheral resistance (r = 0.64; p less than 0.001) were positive. Calculated oxygen transport increased across the whole range of haemoglobin values. These results suggest that adjustment of peripheral resistance in response to oxygen availability overrides the influence of blood viscosity on cardiac output and that the optimum packed cell volume for oxygen transport is the highest that can be achieved. PMID:3083941

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

    PubMed

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

    2010-07-01

    In patients with cardiac failure, bioreactance-based cardiac output (CO) monitoring provides a valid non-invasive method for assessing cardiac performance during exercise. The purpose of this study was to evaluate the efficacy of this technique during strenuous exercise in healthy, trained individuals. Fourteen recreational cyclists, mean (SD) age of 34 (8) years and relative peak oxygen uptake of (VO(2)) 56 (6) ml kg(-1) min(-1), underwent incremental maximal exercise testing, whilst CO was recorded continuously using a novel bioreactance-based device (CO(bio)). The CO(bio) was evaluated against relationship with VO(2), theoretical calculation of arterial-venous oxygen difference (C(a - v) O(2)) and level of agreement with an inert gas rebreathing method (CO(rb)) using a Bland-Altman plot. Bioreactance-based CO measurement was practical and straightforward in application, although there was intermittent loss of electrocardiograph signal at high-intensity exercise. At rest and during exercise, CO(bio) was strongly correlated with VO(2) (r = 0.84; P < 0.001), however, there was evidence of systematic bias with CO(bio) providing lower values than CO(rb); mean bias (limits of agreement) -19% (14.6 to -53%). Likewise, calculated (C(a - v) O(2)) was greater when determined using CO(bio) than CO(rb) (P < 0.001), although both devices provided values in excess of those reported in invasive studies. Bioreactance-based determination of CO provides a pragmatic approach to the continuous assessment of cardiac performance during strenuous exercise in trained individuals. Our findings, however, suggest that further work is needed to refine the key measurement determinants of CO using this device to improve measurement accuracy in this setting. PMID:20336309

  17. The ability of the Vigileo-FloTrac system to measure cardiac output and track cardiac output changes during one-lung ventilation.

    PubMed

    Suehiro, Koichi; Tanaka, Katsuaki; Yamada, Tokuhiro; Matsuura, Tadashi; Mori, Takashi; Funao, Tomoharu; Nishikawa, Kiyonobu

    2015-06-01

    This study was aimed at comparing the cardiac output (CO) measured by the Vigileo™-FloTrac™ system with that estimated by the thermodilution pulmonary artery catheter (PAC) during one-lung ventilation (OLV) and determining the reliability of this system in tracking phenylephrine-induced CO changes during OLV. Sixteen patients scheduled for descending aorta replacement were enrolled. The study was performed 30 min after starting OLV under stable hemodynamic conditions. We recorded hemodynamic variables, CO measured by PAC thermodilution (ICO), CO measured by Vigileo™-FloTrac™ system (Version 3.02, Edwards Lifesciences, Irvine, CA, USA) (APCO), and systemic vascular resistance index (SVRI) before (T0) and after (T1) phenylephrine (100 μg) administration. We used Bland-Altman analysis to compare ICO and APCO. Polar plot and four-quadrant plot were used to assess the tracking ability of the Vigileo™-FloTrac™ system against ICO after administration of phenylephrine. Ninety hemodynamic interventions were performed. Bland-Altman analysis revealed that the mean bias between APCO and ICO was 0.05 L/min and the percentage error, 46.9 %. Four-quadrant plot analysis showed a concordance rate of 24.7 %, while polar plot analysis showed that the concordance rate was 13.3 %; the angular bias, -45.9°; radial limit of agreement, 85.3°. The bias between APCO and ICO was significantly correlated with the SVRI value (p < 0.001, r(2) = 0.822). The reliability of the Vigileo™-FloTrac™ system during OLV to estimate CO and track phenylephrine-induced CO changes was not acceptable. PMID:25212705

  18. [The determination of cardiac output by the dilution of ultrasonic blood density].

    PubMed

    Eremenko, A A; Chaus, N I; Kislukhin, V V; Balykov, I V

    1998-01-01

    The authors propose assessing cardiac output (CO) by diluting the blood ultrasonic properties. For measuring CO, the peripheral artery and vein were connected with a catheter, and ultrasonic flowmetric pickup was attached to the shunt. Indicator (0.9% sodium chloride) was injected into the central vein. Changes in the blood ultrasonic characteristics during the indicator flow were recorded by ultrasonic flowmeter. Dilution curves were computer processed. The method was tried in 7 experimental dogs and clinically in 11 patients and compared with the thermodilution method. The coefficient of correlation was 0.98 in experiment and 0.97 in clinical trials. Dilution of ultrasonic density of the blood helps accurately assess the CO and is highly informative, which is confirmed by a strong correlation with the results of thermodilution. The method is simple, little invasive, realized using available equipment, the indicators are cheap and available, and repeated studies can be performed within short periods of time. PMID:9770808

  19. Reference values for total blood volume and cardiac output in humans

    SciTech Connect

    Williams, L.R.

    1994-09-01

    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.

  20. Decrease of Total Antioxidative Capacity in Developed Low Cardiac Output Syndrome

    PubMed Central

    Kunt, Alper Sami; Andac, Mehmet Halit

    2012-01-01

    Background. It has been known that cardiac surgery induces an oxidative stress. The persistent oxidative stress during reperfusion may lead to depressed myocardial function resulting in low cardiac output syndrome (LCOS) necessitating inotropic or intra-aortic balloon counterpulsation support. Total antioxidant capacity (TAC) is a measurement of oxidative stress in tissues. The purpose of this study was to examine the TAC differences during coronary artery bypass graft (CABG) operation in patients who have developed LCOS and who have not. Material and Methods. Seventy-nine patients were enrolled in the study. Central venous blood samples were obtained immediately before surgery, during operation, and at the end of surgery to assess TAC. Clinical data regarding patient demographics and operative outcomes were prospectively collected and entered into our clinical database. Results. LCOS developed in 8 patients (10.12%). The TAC has decreased sharply in the LCOS patients compared with those who did not develop LCOS (P < 0.001) during operation. In addition, the receiver operating characteristic (ROC) area was 0.879. Conclusion. TAC has decreased during operation in a significant proportion of patients undergoing isolated CABG, and this is more prominent and serious and might be an independent variable in patients who have developed LCOS. This may be related to intraoperative misadventure or inadequate myocardial antioxidative protection. Routine measurement of the TAC during operation may provide information for assessment of the LCOS development. PMID:23251720

  1. Thermodilution and Fick cardiac outputs differ: Impact on pulmonary hypertension evaluation

    PubMed Central

    Fares, Wassim H; Blanchard, Sarah K; Stouffer, George A; Chang, Patricia P; Rosamond, Wayne D; Ford, Hubert James; Aris, Robert M

    2012-01-01

    BACKGROUND: The relationship between thermodilution and indirect Fick cardiac output determination methods has not been well described. OBJECTIVE: To describe the relationship between these two cardiac output determination methods in patients evaluated for pulmonary hypertension and to highlight potential clinical implications. METHODS: A retrospective review of charts of all adult patients who underwent a right heart catheterization (RHC) between January 1, 2007 and November 10, 2010, and participated in the pulmonary hypertension program of the pulmonary division at an academic institution was conducted. For validation, the charts of all patients who underwent RHC during the same period within the cardiology division were reviewed. RESULTS: A total of 198 patients underwent 213 RHCs, 79 (40%) of whom had pulmonary arterial hypertension, were included. Forty-three per cent of patients had >20% difference between thermodilution and Fick. The average difference (thermodilution − Fick ±SD) was −0.39±2.03 L/min (n=213; P=0.006). There was no significant difference in bias or variability between thermodilution and Fick among patients with tricuspid regurgitant jet velocity (TRJ) of <3 m/s versus those with TRJ >3 m/s (−0.41±2.10 L/min versus −0.36±1.93 L/min, respectively; P=0.87). In a multivariable analysis, the thermodilution-Fick difference increased with age (P=0.001). DISCUSSION: The presence of such discrepancy in 36% of patients evaluated for heart failure and/or heart transplant validated the results. In total, 37% of the 1315 procedures (213 performed by pulmonologists and 1102 performed by cardiologists) had a difference of >20% between thermodilution and Fick. CONCLUSION: Significant discrepancy exists between thermodilution and indirect Fick methods. This discrepancy potentially impacts pulmonary arterial hypertension prognostication and diagnosis, and is independent of TRJ. PMID:22891186

  2. Noninvasive aortic bloodflow by Pulsed Doppler Echocardiography (PDE) compared to cardiac output by the direct Fick procedure

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Left ventricular stroke volume was estimated from the systolic velocity integral in the ascending aorta by pulsed Doppler Echocardiography (PDE) and the cross sectional area of the aorta estimated by M mode echocardiography on 15 patients with coronary disease undergoing right catheterization for diagnostic purposes. Cardiac output was calculated from stroke volume and heart volume using the PDE method as well as the Fick procedure for comparison. The mean value for the cardiac output via the PDE method (4.42 L/min) was only 6% lower than for the cardiac output obtained from the Fick procedure (4.69 L/min) and the correlation between the two methods was excellent (r=0.967, p less than .01). The good agreement between the two methods demonstrates that the PDE technique offers a reliable noninvasive alternative for estimating cardiac output, requiring no active cooperation by the subject. It was concluded that the Doppler method is superior to the Fick method in that it provides beat by beat information on cardiac performance.

  3. Thromboresistant surface coatings for the measurement of cardiac output through continuous low flow peripheral A-V shunts.

    PubMed

    Deeb, G M; Borovetz, H S; Griffith, B P; Hardesty, R L

    1980-01-01

    The dilution technique for determining cardiac output using indocyanine green dye is limited in patients weighing less than 20 kg because of the obligatory volume loss. Reproducible achieved using the green dye dilution method by the establishment of a low flow peripheral arteriovenous shunt. The shunt materials were treated with thromboresistant agents--TDMAC (7%) and albumin (1 g/dl)--to facilitate the use of this technique without heparin. For A-V shunt flow rates of 8-30 cc/min reproducible values of cardiac output were obtained for up to 38 hours which were in good agreement with determinations made using the conventional technique of dye dilution. PMID:6986120

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  5. Maintaining low BCR-ABL signaling output to restrict CML progression and enable persistence.

    PubMed

    Burchert, Andreas

    2014-03-01

    Deregulated BCR-ABL oncogenic activity leads to transformation, oncogene addiction and drives disease progression in chronic myeloid leukemia (CML). Inhibition of BCR-ABL using Abl-specific kinase inhibitors (TKI) such as imatinib induces remarkable clinical responses. However, approximately only less than 15 % of all chronic-phase CML patients will remain relapse-free after discontinuation of imatinib in deep molecular remission. It is not well understood why persisting CML cells survive under TKI therapy without developing clonal evolution and frank TKI resistance. BCR-ABL expression level may be critically involved. Whereas higher BCR-ABL expression has been described as a pre-requisite for malignant CML stem cell transformation and CML progression to blast crisis, recent evidence suggests that during persistence TKI select for CML precursors with low BCR-ABL expression. Genetic, translational and clinical evidence is discussed to suggest that TKI-induced maintenance of low BCR-ABL signaling output may be potently tumor suppressive, because it abrogates oncogenic addiction. PMID:24500518

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

  7. Quantification of the Impaired Cardiac Output Response to Exercise in Heart Failure: Application of a Non-Invasive Device

    PubMed Central

    Myers, Jonathan; Gujja, Pradeep; Neelagaru, Suresh; Hsu, Leon; Burkhoff, Daniel

    2009-01-01

    An impaired cardiac output (CO) response to exercise is a hallmark of chronic heart failure (CHF), and the degree to which CO is impaired is related to the severity of CHF and prognosis. However, practical methods for obtaining cardiac output during exercise are lacking, and what constitutes and impaired response is unclear. Forty six CHF patients and 13 normal subjects underwent cardiopulmonary exercise testing (CPX) while CO and other hemodynamic measurements at rest and during exercise were obtained using a novel, non-invasive, bioreactance device based on assessment of relative phase shifts of electric currents injected across the thorax, heart rate and ventricular ejection time. An abnormal cardiac output response to exercise was defined as achieving ≤ 95% of the confidence limits of the slope of the relationship between CO and oxygen uptake (VO2). An impaired CO slope identified patients with more severe CHF as evidenced by a lower peak VO2, lower peak CO, heightened VE/VCO2 slope, and lower oxygen uptake efficiency slope. CO can be estimated during exercise using a novel bioreactance technique; patients with an impaired response to exercise exhibit reduced exercise capacity and inefficient ventilation typical of more severe CHF. Non- invasive measurement of cardiac performance in response to exercise provides a simple method of identifying patients with more severe CHF and may complement the CPX in identifying CHF patients at high risk. Key points Non-invasive measurement of cardiac output during exercise is feasible in patients with heart failure. Impairment in the CO response to exercise identifies heart failure patients with more severe disease, lower exercise capacity and inefficient ventilation. Non-invasive measurement of cardiac performance during exercise has potentially important applications for the functional and prognostic assessment of patients with heart failure. PMID:24149996

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

    NASA Technical Reports Server (NTRS)

    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

    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.

  9. Non-invasive measurement of cardiac output: evaluation of new infrared absorption spectrometer.

    PubMed

    Baum, M M; Moss, J A; Kumar, S; Wagner, P D

    2006-09-28

    The mass spectrometer (MS) traditionally has been the instrument of choice for measuring cardiac output (Q (T)) non-invasively using the foreign gas uptake method. However, the size and cost of the MS has hampered widespread adoption of this technique outside of the laboratory. Here, we present results, from six normal human subjects at rest and during exercise, of simultaneous Q (T) measurements by an MS and a new, portable infrared (IR) device developed in our laboratories. These measurements are made using on the open-circuit acetylene uptake method. The IR device measures inspired and end-tidal concentrations of acetylene, sulfur hexafluoride, and carbon dioxide by IR absorption spectroscopy with a 10-90% response time of 43 ms; accurate measurements were made down to sample flow rates of 50 mL min(-1). Excellent correlation [Q (T)(IR)=0.98 Q (T)(MS), R(2)=0.94] was observed between instruments across the range from rest to heavy exercise. These results suggest that the IR device, which is small, light-weight, and rugged may enable the foreign gas uptake method to be used in clinical, field, and point-of-care settings for Q (T) measurement. PMID:16326150

  10. High Output Cardiac Failure Resolving after Repair of AV Fistula in a Six-Month-Old

    PubMed Central

    Teomete, Uygar; Gugol, Rubee Anne; Neville, Holly; Dandin, Ozgur; Young, Ming-Lon

    2016-01-01

    Background. Acquired AVF in pediatrics are commonly caused by iatrogenic means, including arterial or venous punctures. These fistulae can cause great hemodynamic stress on the heart as soon as they are created. Case. A six-month-old 25-week gestation infant was referred for respiratory distress. Initial exam revealed tachypnea, tachycardia, and hypertension. There was a bruit noted on her left arm. An ultrasound showed an arteriovenous fistula. Its location, however, precluded intervention because of the high risk for limb-loss. An echocardiogram showed evidence of pulmonary hypertension that was treated with sildenafil and furosemide. However, no improvement was seen. On temporary manual occlusion of the fistula, the patient was noted to have increased her blood pressure and decreased her heart rate, suggesting significant hemodynamic effect of the fistula. The fistula was subsequently ligated and the patient clinically and echocardiographically improved. Conclusion. A patient in high output cardiac failure or pulmonary artery hypertension, especially prematüre patients with preexisting lung disease, should be probed for history of multiple punctures, trauma, or surgery and should have prompt evaluation for AVF. If it can be diagnosed and repaired, most of the cases have been shown to decrease the stress on the heart and reverse the pathologic hemodynamics. PMID:26885434

  11. A computational model-based validation of Guyton's analysis of cardiac output and venous return curves

    NASA Technical Reports Server (NTRS)

    Mukkamala, R.; Cohen, R. J.; Mark, R. G.

    2002-01-01

    Guyton developed a popular approach for understanding the factors responsible for cardiac output (CO) regulation in which 1) the heart-lung unit and systemic circulation are independently characterized via CO and venous return (VR) curves, and 2) average CO and right atrial pressure (RAP) of the intact circulation are predicted by graphically intersecting the curves. However, this approach is virtually impossible to verify experimentally. We theoretically evaluated the approach with respect to a nonlinear, computational model of the pulsatile heart and circulation. We developed two sets of open circulation models to generate CO and VR curves, differing by the manner in which average RAP was varied. One set applied constant RAPs, while the other set applied pulsatile RAPs. Accurate prediction of intact, average CO and RAP was achieved only by intersecting the CO and VR curves generated with pulsatile RAPs because of the pulsatility and nonlinearity (e.g., systemic venous collapse) of the intact model. The CO and VR curves generated with pulsatile RAPs were also practically independent. This theoretical study therefore supports the validity of Guyton's graphical analysis.

  12. Gas mixing apparatus for determining cardiac output by CO2 rebreathing.

    PubMed

    Bassett, D R; Fitton, T R

    1995-12-01

    The carbon dioxide rebreathing technique is widely used for determination of cardiac output during exercise. The equilibration method of Collier et at. (J. Appl. Physiol. 9:25, 1956) is generally preferred over the exponential method of Defares (J. Appl. Physiol. 13:159, 1968). However, the equilibration method requires the volume and initial CO2 percentage in the rebreathing bag to be adjusted according to the work rate. A device for mixing two gases (100% O2 and 20% CO2/80% O2) was constructed for this purpose. Multistage regulators are attached to the gas tanks and connected to a medical gas mixer via high-pressure air hoses. A variable time-delay switch causes a solenoid valve to open for 1.0-10s to deliver a predetermined gas volume. The device was found to accurately deliver a preset volume and concentration of gas to the rebreathing bag. A gas mixing apparatus simplifies the equilibration CO2 rebreathing technique by allowing the investigator to easily select the initial volume and percentage of CO2. PMID:8614328

  13. High Output Cardiac Failure Resolving after Repair of AV Fistula in a Six-Month-Old.

    PubMed

    Teomete, Uygar; Gugol, Rubee Anne; Neville, Holly; Dandin, Ozgur; Young, Ming-Lon

    2016-01-01

    Background. Acquired AVF in pediatrics are commonly caused by iatrogenic means, including arterial or venous punctures. These fistulae can cause great hemodynamic stress on the heart as soon as they are created. Case. A six-month-old 25-week gestation infant was referred for respiratory distress. Initial exam revealed tachypnea, tachycardia, and hypertension. There was a bruit noted on her left arm. An ultrasound showed an arteriovenous fistula. Its location, however, precluded intervention because of the high risk for limb-loss. An echocardiogram showed evidence of pulmonary hypertension that was treated with sildenafil and furosemide. However, no improvement was seen. On temporary manual occlusion of the fistula, the patient was noted to have increased her blood pressure and decreased her heart rate, suggesting significant hemodynamic effect of the fistula. The fistula was subsequently ligated and the patient clinically and echocardiographically improved. Conclusion. A patient in high output cardiac failure or pulmonary artery hypertension, especially prematüre patients with preexisting lung disease, should be probed for history of multiple punctures, trauma, or surgery and should have prompt evaluation for AVF. If it can be diagnosed and repaired, most of the cases have been shown to decrease the stress on the heart and reverse the pathologic hemodynamics. PMID:26885434

  14. [A dye densitometry analysis method for noninvasive measurement of cardiac output based on NIRS].

    PubMed

    Lu, Meng-Meng; Wang, Hong-Xuan; Liu, Guang-Da; Xin, Gui-Jie; Yu, Yong; Zha, Yu-Tong

    2013-12-01

    Currently, there exist technology problems in cardiac output (CO) parameter detection clinically, such as invasive and complex operation, as well as possibility of infection and death for patients. In order to solve these problems, a noninvasive and continuous method based on NIRS for CO detection was presented. In this way, the concentration changing of indocyanine green (ICG) dye in the patient's arterial blood was dynamically measured and analyzed, so that the CO could be noninvasively and continuously measured according to the characteristic parameters of dye densitometry curve. While the ICG dye was injected into the patient's body by the median cubital vein, block of photoelectric pulse dye densitometry measurement system as the lower machine acquired pulse wave data and uploaded the data to upper computer. In the scheme, two specialized light sources of LED at 940 and 805 nm were used to capture the signals of sufferer's fingertip pulse wave synchronously and successively. The CO value could then be successfully calculated through drawing complete ICG concentration variation of dye dilution and excretion process and computing mean transmission time (MTT) by upper computer. Compared with the "gold standard" method of thermodilution, the maximum relative error of this method was below 9. 76%, and the mean relative error was below 4. 39%. The result indicates that the method can be used as a kind of convenient operation, noninvasive and continuous solution for clinical CO measurement. PMID:24611365

  15. May-Thurner syndrome: High output cardiac failure as a result of iatrogenic iliac fistula

    PubMed Central

    Singh, Shantanu; Singh, Shivank; Jyothimallika, Juthika; Lynch, Teresa J

    2015-01-01

    May-Thurner syndrome (MTS) also termed iliocaval compression or Cockett-Thomas syndrome is a common, although rarely diagnosed, condition in which the patient has an anatomical variant wherein the right common iliac artery overlies and compresses the left common iliac vein against the fifth lumbar spine resulting in increased risk of iliofemoral deep venous thrombosis. This variant has been shown to be present in over 23% of the population but most go undetected. We present a patient with MTS who developed high output cardiac failure due to an iatrogenic iliac fistula. The patient underwent an extensive workup for a left to right shunt including MRI and arterial duplex in the vascular lab. He was ultimately found to have a 2.1 cm left common iliac artery aneurysm and history of common iliac stent. We took the patient to the operating room for aortogram with placement of an endovascular plug of the left internal iliac artery and aorto-bi-iliac stent graft placement with CO2 and IV contrast. Subsequently the patient underwent successful stent placement in the area that was compressed followed by 6 mo of anticoagulation with warfarin. The flow from the fistula decreased significantly. PMID:25789305

  16. Evaluation of coronary blood flow velocity during cardiac arrest with circulation maintained through mechanical chest compressions in a porcine model

    PubMed Central

    2011-01-01

    Background Mechanical chest compressions (CCs) have been shown capable of maintaining circulation in humans suffering cardiac arrest for extensive periods of time. Reports have documented a visually normalized coronary blood flow during angiography in such cases (TIMI III flow), but it has never been actually measured. Only indirect measurements of the coronary circulation during cardiac arrest with on-going mechanical CCs have been performed previously through measurement of the coronary perfusion pressure (CPP). In this study our aim was to correlate average peak coronary flow velocity (APV) to CPP during mechanical CCs. Methods In a closed chest porcine model, cardiac arrest was established through electrically induced ventricular fibrillation (VF) in eleven pigs. After one minute, mechanical chest compressions were initiated and then maintained for 10 minutes upon which the pigs were defibrillated. Measurements of coronary blood flow in the left anterior descending artery were made at baseline and during VF with a catheter based Doppler flow fire measuring APV. Furthermore measurements of central (thoracic) venous and arterial pressures were also made in order to calculate the theoretical CPP. Results Average peak coronary flow velocity was significantly higher compared to baseline during mechanical chests compressions and this was observed during the entire period of mechanical chest compressions (12 - 39% above baseline). The APV slowly declined during the 10 min period of mechanical chest compressions, but was still higher than baseline at the end of mechanical chest compressions. CPP was simultaneously maintained at > 20 mmHg during the 10 minute episode of cardiac arrest. Conclusion Our study showed good correlation between CPP and APV which was highly significant, during cardiac arrest with on-going mechanical CCs in a closed chest porcine model. In addition APV was even higher during mechanical CCs compared to baseline. Mechanical CCs can, at minimum, re-establish coronary blood flow in non-diseased coronary arteries during cardiac arrest. PMID:22182425

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

    SciTech Connect

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

    1984-01-01

    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.

  18. Low Cardiac Output Leads Hepatic Fibrosis in Right Heart Failure Model Rats

    PubMed Central

    Fujimoto, Yoshitaka; Urashima, Takashi; Shimura, Daisuke; Ito, Reiji; Kawachi, Sadataka; Kajimura, Ichige; Akaike, Toru; Kusakari, Yoichiro; Fujiwara, Masako; Ogawa, Kiyoshi; Goda, Nobuhito; Ida, Hiroyuki; Minamisawa, Susumu

    2016-01-01

    Background Hepatic fibrosis progresses with right heart failure, and becomes cardiac cirrhosis in a severe case. Although its causal factor still remains unclear. Here we evaluated the progression of hepatic fibrosis using a pulmonary artery banding (PAB)-induced right heart failure model and investigated whether cardiac output (CO) is responsible for the progression of hepatic fibrosis. Methods and Results Five-week-old Sprague-Dawley rats divided into the PAB and sham-operated control groups. After 4 weeks from operation, we measured CO by echocardiography, and hepatic fibrosis ratio by pathological examination using a color analyzer. In the PAB group, CO was significantly lower by 48% than that in the control group (78.2±27.6 and 150.1±31.2 ml/min, P<0.01). Hepatic fibrosis ratio and serum hyaluronic acid, an index of hepatic fibrosis, were significantly increased in the PAB group than those in the control group (7.8±1.7 and 1.0±0.2%, P<0.01, 76.2±27.5 and 32.7±7.5 ng/ml, P<0.01). Notably, the degree of hepatic fibrosis significantly correlated a decrease in CO. Immunohistological analysis revealed that hepatic stellate cells were markedly activated in hypoxic areas, and HIF-1α positive hepatic cells were increased in the PAB group. Furthermore, by real-time PCR analyses, transcripts of profibrotic and fibrotic factors (TGF-β1, CTGF, procollargen I, procollargen III, MMP 2, MMP 9, TIMP 1, TIMP 2) were significantly increased in the PAB group. In addition, western blot analyses revealed that the protein level of HIF-1α was significantly increased in the PAB group than that in the control group (2.31±0.84 and 1.0±0.18 arbitrary units, P<0.05). Conclusions Our study demonstrated that low CO and tissue hypoxia were responsible for hepatic fibrosis in right failure heart model rats. PMID:26863419

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

    PubMed Central

    Neal, Maxwell Lewis; Bassingthwaighte, James B.

    2010-01-01

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

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

    PubMed

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

    2008-03-01

    Several rebreathing methods are available for cardiac output (Q (T)) measurement. The aims of this study were threefold: first, to compare values for resting Q (T) produced by the equilibrium-CO(2), exponential-CO(2) and inert gas-N(2)O rebreathing methods and, second, to evaluate the reproducibility of these three methods at rest. The third aim was to assess the agreement between estimates of peak exercise Q (T) derived from the exponential and inert gas rebreathing methods. A total of 18 healthy subjects visited the exercise laboratory on different days. Repeated measures of Q (T), measured in a seated position, were separated by a 5 min rest period. Twelve participants performed an incremental exercise test to determine peak oxygen consumption. Two more exercise tests were used to measure Q (T) at peak exercise using the exponential and inert gas rebreathing methods. The exponential method produced significantly higher estimates at rest (averaging 10.9 l min(-1)) compared with the equilibrium method (averaging 6.6 l min(-1)) and the inert gas rebreathing method (averaging 5.1 l min(-1); P < 0.01). All methods were highly reproducible with the exponential method having the largest coefficient of variation (5.3%). At peak exercise, there were non-significant differences between the exponential and inert gas rebreathing methods (P = 0.14). The limits of agreement were -0.49 to 0.79 l min(-1). Due to the ability to evaluate the degree of gas mixing and to estimate intra-pulmonary shunt, we believe that the inert gas rebreathing method has the potential to measure Q (T) more precisely than either of the CO(2) rebreathing methods used in this study. At peak exercise, the exponential and inert gas rebreathing methods both showed acceptable limits of agreement. PMID:18074146

  1. Bioreactance Is Not Interchangeable with Thermodilution for Measuring Cardiac Output during Adult Liver Transplantation

    PubMed Central

    Han, Sangbin; Lee, Jong Hwan; Kim, Gaabsoo; Ko, Justin Sangwook; Choi, Soo Joo; Kwon, Ji Hae; Heo, Burn Young; Gwak, Mi Sook

    2015-01-01

    Background Thermodilution technique using a pulmonary artery catheter is widely used for the assessment of cardiac output (CO) in patients undergoing liver transplantation. However, the unclearness of the risk-benefit ratio of this method has led to an interest in less invasive modalities. Thus, we evaluated whether noninvasive bioreactance CO monitoring is interchangeable with thermodilution technique. Methods Nineteen recipients undergoing adult-to-adult living donor liver transplantation were enrolled in this prospective observational study. COs were recorded automatically by the two devices and compared simultaneously at 3-minute intervals. The Bland–Altman plot was used to evaluate the agreement between bioreactance and thermodilution. Clinically acceptable agreement was defined as a percentage error of limits of agreement <30%. The four quadrant plot was used to evaluate concordance between bioreactance and thermodilution. Clinically acceptable concordance was defined as a concordance rate >92%. Results A total of 2640 datasets were collected. The mean CO difference between the two techniques was 0.9 l/min, and the 95% limits of agreement were -3.5 l/min and 5.4 l/min with a percentage error of 53.9%. The percentage errors in the dissection, anhepatic, and reperfusion phase were 50.6%, 56.1%, and 53.5%, respectively. The concordance rate between the two techniques was 54.8%. Conclusion Bioreactance and thermodilution failed to show acceptable interchangeability in terms of both estimating CO and tracking CO changes in patients undergoing liver transplantation. Thus, the use of bioreactance as an alternative CO monitoring to thermodilution, in spite of its noninvasiveness, would be hard to recommend in these surgical patients. PMID:26017364

  2. Predictors of Post Pericardiotomy Low Cardiac Output Syndrome in Patients With Pericardial Effusion

    PubMed Central

    Sabzi, Feridoun; Faraji, Reza

    2015-01-01

    Introduction: Pathological involvement of pericardium by any disease that resulting in effusion may require decompression and pericardiectomy. The current article describes rare patients with effusion who after pericadiectomy and transient hemodynamic improvement rapidly developed progressive heart failure and subsequent multi organ failure. Methods: During periods of five years, 423 patients in our hospital underwent pericardiotomy for decompression of effusion. The clinical characteristics of those patient with postoperative low cardiac output (B group) (14 cases) recorded and compared with other patients without this postoperative complication (A group) by test and X2. Significant variables in invariables (P≤0.1) entered in logistic regression analysis and odd ratio of these significant variables obtained. Results: Idiopathic pericardial effusion, malignancy, renal failure, connective tissue disease, viral pericarditis was found in 125 patients (27%), 105 patients (25.4%), 65 patients (15.6%), 50 (17.1%) and 10 (2.4%) of patients subsequently. The factors that predict post-operative death in logistic regression analysis were malignancy, radiotherapy, constrictive pericarditis inotropic drug using IABP using, pre-operative EF and pericardial calcification. Conclusion: Certain preoperative variables such as malignancy, radiotherapy, low EF, calcified pericardium and connective tissue disease are associated with POLCOS and post-operative risk of death. This paradoxical response to pericardial decompression may be more frequent than currently appreciated. Its cause may relate to the sudden removal of the chronic external ventricular support from the effusion or thicken pericardium resulting in ventricular dilatation and failure or intra operative myocardial injury due to pericardiectomy of calcified pericardium, radiation and cardiomyopathy. PMID:25859311

  3. Cardiac output distribution in miniature swine during locomotory exercise to VO/sub 3max/

    SciTech Connect

    Armstrong, R.B.; Delp, M.D.; Laughlin, M.H.

    1986-03-01

    Distribution of cardiac output (CO) was studied in miniature swine (22 +/- 1 kg) during level treadmill exercise up to the speed (17.7 km/hr) that elicited maximal oxygen consumption (VO/sub 2max/) (60 +/- 4 m1/min/kg). COs and tissue blood flows (BFs) were measured with the radiolabelled microsphere technique. CO increased from a preexercise value of 2.1 +/- 0.5 1/min up to 9.9 +/- 0.5 1/min at VO/sub 2max/. In preexercise standing 43% of CO went to skeletal muscle, which comprised 36 +/- 1% of body mass, 42% to viscera (12 +/- 1% mass), 5% to brain, heart, and lungs (2% +/- 0.1% mass), and 10% to skin and skeleton (35 +/- 2% mass). Preexercise could not be considered resting because of the animals' excitability. Skeletal muscle BF increased progressively with speed up to VO/sub 2max/, both in absolute terms and in percent CO. At VO/sub 2max/, 88% of CO went to muscle, 3% to viscera, 8% to brain, heart and lungs, and 1% to skin and skeleton. Thus, at VO/sub 2max/ only 4% of CO went to the inactive tissues, which constituted 47% of body mass. In 2 pigs that ran at speeds above 17 km/hr, total muscle BF leveled off at VO/sub 2max/. These findings demonstrate that muscle BF progressively increases up to VO/sub 2max/, and that VO/sub 2/ levels off at the same intensity as muscle flow.

  4. Omega-3 fatty acid supplementation enhances stroke volume and cardiac output during dynamic exercise.

    PubMed

    Walser, Buddy; Stebbins, Charles L

    2008-10-01

    Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have beneficial effects on cardiovascular function. We tested the hypotheses that dietary supplementation with DHA (2 g/day) + EPA (3 g/day) enhances increases in stroke volume (SV) and cardiac output (CO) and decreases in systemic vascular resistance (SVR) during dynamic exercise. Healthy subjects received DHA + EPA (eight men, four women) or safflower oil (six men, three women) for 6 weeks. Both groups performed 20 min of bicycle exercise (10 min each at a low and moderate work intensity) before and after DHA + EPA or safflower oil treatment. Mean arterial pressure (MAP), heart rate (HR), SV, CO, and SVR were assessed before exercise and during both workloads. HR was unaffected by DHA + EPA and MAP was reduced, but only at rest (88 +/- 5 vs. 83 +/- 4 mm Hg). DHA + EPA augmented increases in SV (14.1 +/- 6.3 vs. 32.3 +/- 8.7 ml) and CO (8.5 +/- 1.0 vs. 10.3 +/- 1.2 L/min) and tended to attenuate decreases in SVR (-7.0 +/- 0.6 vs. -10.1 +/- 1.6 mm Hg L(-1) min(-1)) during the moderate workload. Safflower oil treatment had no effects on MAP, HR, SV, CO or SVR at rest or during exercise. DHA + EPA-induced increases in SV and CO imply that dietary supplementation with these fatty acids can increase oxygen delivery during exercise, which may have beneficial clinical implications for individuals with cardiovascular disease and reduced exercise tolerance. PMID:18563435

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

    PubMed Central

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

    2009-01-01

    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. PMID:19821993

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

    PubMed

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

    2012-05-01

    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

  7. Assessment of the effect of vasodilators on the distribution of cardiac output by whole-body Thallium imaging

    SciTech Connect

    Juni, J.E.; Wallis, J.; Diltz, E.; Nicholas, J.; Lahti, D.; Pitt, B.

    1985-05-01

    Vasodilator therapy (tx) of congestive heart failure (CHF) has been shown to be effective in increasing cardiac output (CO) and lowering vascular resistance. Unfortunately, these hemodynamic effects are not usually accompanied by improved peripheral circulation of exercise capacity. To assess the effect of a new vasodilator, Cl-914, on the redistribution of CO to the peripheral circulation, the authors performed testing whole-body thallium scanning (WB-Th) on 6 patients (pts) with severe CHF. Immediately following i.v. injection of 1.5 mCi Th-201, WB scanning was performed from anterior and posterior views. Regions of interest were defined for the peripheral (P) muscles (legs and arms), central torso (C), and splanchnic bed (S). The geometric mean of activity in these regions was calculated from both views. Each pt was studied before tx and again, after 1 week on tx. Invasive measurements revealed that all pts had significant improvements in resting cardiac output (mean increase 49%) and vascular resistance (mean decrease 30%). Unlike other vasodilators, all CI-914 pts had a significant improvement in treadmill exercise capacity (mean increase 54%). WB-Th revealed a significant shift in CO to the peripheral circulation with P:C increased 33.2% (rho= .001) and P:S increased 29% (rho=.01). Vasoactive drugs may significantly alter the relative distribution of cardiac output. WB-Th scanning provides a simple quantitative means of following such changes.

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

    PubMed Central

    2011-01-01

    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) PMID:21676229

  9. Bioreactance: a new tool for cardiac output and thoracic fluid content monitoring during hemodialysis.

    PubMed

    Kossari, Niloufar; Hufnagel, Gilles; Squara, Pierre

    2009-10-01

    Outpatient hemodialysis therapy (HD) can be associated with hemodynamic compromise. Bioreactance has recently been shown to provide accurate, noninvasive, continuous, measurements of cardiac output (CO) and thoracic impedance (Zo) from which thoracic fluid content (TFC) can be derived assuming TFC=1000/Zo. This study was designed to evaluate the changes in TFC in comparison with the traditional indices of fluid removal (FR) and to understand the trends in CO changes in HD patients. Minute-by-minute changes in TFC and CO were prospectively collected using the bioreactance system (NICOM) in HD patients of a single unit. Changes in body weight (DeltaW), hematocrit (DeltaHct), and amount of FR were also measured. Twenty-five patients (age 77 +/- 11 years) were included. The TFC decreased in all patients by an average of 5.4 +/- 7.9 kohm(-1), weight decreased by 1.48 +/- 0.98 kg, and FR averaged 2.07 +/- 1.93 L over a 3- to 4-hour HD session. There were good correlations between DeltaTFC and DeltaW (R=0.80, P<0.0001) and FR (R=0.85, P<0.0001). DeltaHct (4.13 +/- 3.42%) was poorly correlated with DeltaTFC (R=0.35, P=0.12) and FR (R=0.40, P=0.07). The regression line between FR and TFC yielded FR=1.0024-0.1985TFC; thus, a 1 kohm(-1) change of Zo correlates with an approximately 200 mL change in total body water. The change in CO (-0.52 +/- 0.49 L/min m(2)) during HD did not correlate with FR (R=0.15, P=NS). Changes in TFC represented the monitored variable most closely related to FR. CO remained fairly constant in this stable patient cohort. Further studies in high-risk patients are warranted to understand whether TFC and CO monitoring can improve HD session management. PMID:19758300

  10. Simple suspension culture system of human iPS cells maintaining their pluripotency for cardiac cell sheet engineering.

    PubMed

    Haraguchi, Yuji; Matsuura, Katsuhisa; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

    2015-12-01

    In this study, a simple three-dimensional (3D) suspension culture method for the expansion and cardiac differentiation of human induced pluripotent stem cells (hiPSCs) is reported. The culture methods were easily adapted from two-dimensional (2D) to 3D culture without any additional manipulations. When hiPSCs were directly applied to 3D culture from 2D in a single-cell suspension, only a few aggregated cells were observed. However, after 3?days, culture of the small hiPSC aggregates in a spinner flask at the optimal agitation rate created aggregates which were capable of cell passages from the single-cell suspension. Cell numbers increased to approximately 10-fold after 12?days of culture. The undifferentiated state of expanded hiPSCs was confirmed by flow cytometry, immunocytochemistry and quantitative RT-PCR, and the hiPSCs differentiated into three germ layers. When the hiPSCs were subsequently cultured in a flask using cardiac differentiation medium, expression of cardiac cell-specific genes and beating cardiomyocytes were observed. Furthermore, the culture of hiPSCs on Matrigel-coated dishes with serum-free medium containing activin A, BMP4 and FGF-2 enabled it to generate robust spontaneous beating cardiomyocytes and these cells expressed several cardiac cell-related genes, including HCN4, MLC-2a and MLC-2v. This suggests that the expanded hiPSCs might maintain the potential to differentiate into several types of cardiomyocytes, including pacemakers. Moreover, when cardiac cell sheets were fabricated using differentiated cardiomyocytes, they beat spontaneously and synchronously, indicating electrically communicative tissue. This simple culture system might enable the generation of sufficient amounts of beating cardiomyocytes for use in cardiac regenerative medicine and tissue engineering. Copyright 2013 John Wiley & Sons, Ltd. PMID:23728860

  11. Effects of hypertrophic and dilated cardiomyopathy mutations on power output by human β-cardiac myosin.

    PubMed

    Spudich, James A; Aksel, Tural; Bartholomew, Sadie R; Nag, Suman; Kawana, Masataka; Yu, Elizabeth Choe; Sarkar, Saswata S; Sung, Jongmin; Sommese, Ruth F; Sutton, Shirley; Cho, Carol; Adhikari, Arjun S; Taylor, Rebecca; Liu, Chao; Trivedi, Darshan; Ruppel, Kathleen M

    2016-01-01

    Hypertrophic cardiomyopathy is the most frequently occurring inherited cardiovascular disease, with a prevalence of more than one in 500 individuals worldwide. Genetically acquired dilated cardiomyopathy is a related disease that is less prevalent. Both are caused by mutations in the genes encoding the fundamental force-generating protein machinery of the cardiac muscle sarcomere, including human β-cardiac myosin, the motor protein that powers ventricular contraction. Despite numerous studies, most performed with non-human or non-cardiac myosin, there is no clear consensus about the mechanism of action of these mutations on the function of human β-cardiac myosin. We are using a recombinantly expressed human β-cardiac myosin motor domain along with conventional and new methodologies to characterize the forces and velocities of the mutant myosins compared with wild type. Our studies are extending beyond myosin interactions with pure actin filaments to include the interaction of myosin with regulated actin filaments containing tropomyosin and troponin, the roles of regulatory light chain phosphorylation on the functions of the system, and the possible roles of myosin binding protein-C and titin, important regulatory components of both cardiac and skeletal muscles. PMID:26792326

  12. 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)

    Soukup, Ladislav; Vondra, Vlastimil; Viščor, Ivo; Jurák, Pavel; Halámek, Josef

    2013-04-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  14. At high cardiac output, diesel exhaust exposure increases pulmonary vascular resistance and decreases distensibility of pulmonary resistive vessels.

    PubMed

    Wauters, Aurélien; Vicenzi, Marco; De Becker, Benjamin; Riga, Jean-Philippe; Esmaeilzadeh, Fatemeh; Faoro, Vitalie; Vachiéry, Jean-Luc; van de Borne, Philippe; Argacha, Jean-François

    2015-12-15

    Air pollution has recently been associated with the development of acute decompensated heart failure, but the underlying biological mechanisms remain unclear. A pulmonary vasoconstrictor effect of air pollution, combined with its systemic effects, may precipitate decompensated heart failure. The aim of the present study was to investigate the effects of acute exposure to diesel exhaust (DE) on pulmonary vascular resistance (PVR) under resting and stress conditions but also to determine whether air pollution may potentiate acquired pulmonary hypertension. Eighteen healthy male volunteers were exposed to ambient air (AA) or dilute DE with a particulate matter of <2.5 μm concentration of 300 μg/m(3) for 2 h in a randomized, crossover study design. The effects of DE on PVR, on the coefficient of distensibilty of pulmonary vessels (α), and on right and left ventricular function were evaluated at rest (n = 18), during dobutamine stress echocardiography (n = 10), and during exercise stress echocardiography performed in hypoxia (n = 8). Serum endothelin-1 and fractional exhaled nitric oxide were also measured. At rest, exposure to DE did not affect PVR. During dobutamine stress, the slope of the mean pulmonary artery pressure-cardiac output relationship increased from 2.8 ± 0.5 mmHg · min · l (-1) in AA to 3.9 ± 0.5 mmHg · min · l (-1) in DE (P < 0.05) and the α coefficient decreased from 0.96 ± 0.15 to 0.64 ± 0.12%/mmHg (P < 0.01). DE did not further enhance the hypoxia-related upper shift of the mean pulmonary artery pressure-cardiac output relationship. Exposure to DE did not affect serum endothelin-1 concentration or fractional exhaled nitric oxide. In conclusion, acute exposure to DE increased pulmonary vasomotor tone by decreasing the distensibility of pulmonary resistive vessels at high cardiac output. PMID:26497960

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

    PubMed Central

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

    2008-01-01

    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. PMID:18957114

  16. The thick left ventricular wall of the giraffe heart normalises wall tension, but limits stroke volume and cardiac output.

    PubMed

    Smerup, Morten; Damkjær, Mads; Brøndum, Emil; Baandrup, Ulrik T; Kristiansen, Steen Buus; Nygaard, Hans; Funder, Jonas; Aalkjær, Christian; Sauer, Cathrine; Buchanan, Rasmus; Bertelsen, Mads Frost; Østergaard, Kristine; Grøndahl, Carsten; Candy, Geoffrey; Hasenkam, J Michael; Secher, Niels H; Bie, Peter; Wang, Tobias

    2016-02-01

    Giraffes - the tallest extant animals on Earth - are renowned for their high central arterial blood pressure, which is necessary to secure brain perfusion. Arterial pressure may exceed 300 mmHg and has historically been attributed to an exceptionally large heart. Recently, this has been refuted by several studies demonstrating that the mass of giraffe heart is similar to that of other mammals when expressed relative to body mass. It thus remains unexplained how the normal-sized giraffe heart generates such massive arterial pressures. We hypothesized that giraffe hearts have a small intraventricular cavity and a relatively thick ventricular wall, allowing for generation of high arterial pressures at normal left ventricular wall tension. In nine anaesthetized giraffes (495±38 kg), we determined in vivo ventricular dimensions using echocardiography along with intraventricular and aortic pressures to calculate left ventricular wall stress. Cardiac output was also determined by inert gas rebreathing to provide an additional and independent estimate of stroke volume. Echocardiography and inert gas-rebreathing yielded similar cardiac outputs of 16.1±2.5 and 16.4±1.4 l min(-1), respectively. End-diastolic and end-systolic volumes were 521±61 ml and 228±42 ml, respectively, yielding an ejection fraction of 56±4% and a stroke volume of 0.59 ml kg(-1). Left ventricular circumferential wall stress was 7.83±1.76 kPa. We conclude that, relative to body mass, a small left ventricular cavity and a low stroke volume characterizes the giraffe heart. The adaptations result in typical mammalian left ventricular wall tensions, but produce a lowered cardiac output. PMID:26643090

  17. Influence of water immersion, water gymnastics and swimming on cardiac output in patients with heart failure

    PubMed Central

    Schmid, Jean‐Paul; Noveanu, Markus; Morger, Cyrill; Gaillet, Raymond; Capoferri, Mauro; Anderegg, Matthias; Saner, Hugo

    2007-01-01

    Background Whole‐body water immersion leads to a significant shift of blood from the periphery to the intrathoracic circulation, followed by an increase in central venous pressure and heart volume. In patients with severely reduced left ventricular function, this hydrostatically induced volume shift might overstrain the cardiovascular adaptive mechanisms and lead to cardiac decompensation. Aim To assess the haemodynamic response to water immersion, gymnastics and swimming in patients with chronic heart failure (CHF). Methods 10 patients with compensated CHF (62.9 (6.3) years, ejection fraction 31.5% (4.1%), peak oxygen consumption (V̇o2) 19.4 (2.8) ml/kg/min), 10 patients with coronary artery disease (CAD) but preserved left ventricular function (57.2 (5.6) years, ejection fraction 63.9% (5.5%), peak V̇o2 28 (6.3) ml/kg/min), and 10 healthy controls (32.8 (7.2) years, peak V̇o2 45.6 (6) ml/kg/min) were examined. Haemodynamic response to thermoneutral (32°C) water immersion and exercise was measured using a non‐invasive foreign gas rebreathing method during stepwise water immersion, water gymnastics and swimming. Results Water immersion up to the chest increased cardiac index by 19% in controls, by 21% in patients with CAD and by 16% in patients with CHF. Although some patients with CHF showed a decrease of stroke volume during immersion, all subjects were able to increase cardiac index (by 87% in healthy subjects, by 77% in patients with CAD and by 53% in patients with CHF). V̇o2 during swimming was 9.7 (3.3) ml/kg/min in patients with CHF, 12.4 (3.5) ml/kg/min in patients with CAD and 13.9 (4) ml/kg/min in controls. Conclusions Patients with severely reduced left ventricular function but stable clinical conditions and a minimal peak V̇o2 of at least 15 ml/kg/min during a symptom‐limited exercise stress test tolerate water immersion and swimming in thermoneutral water well. Although cardiac index and V̇o2 are lower than in patients with CAD with preserved left ventricular function and controls, these patients are able to increase cardiac index adequately during water immersion and swimming. PMID:17164483

  18. Evaluating cardiac physiology through echocardiography in bottlenose dolphins: using stroke volume and cardiac output to estimate systolic left ventricular function during rest and following exercise.

    PubMed

    Miedler, Stefan; Fahlman, Andreas; Valls Torres, Mónica; Álvaro Álvarez, Teresa; Garcia-Parraga, Daniel

    2015-11-01

    Heart-rate (fH) changes during diving and exercise are well documented for marine mammals, but changes in stroke volume (SV) and cardiac output (CO) are much less known. We hypothesized that both SV and CO are also modified following intense exercise. Using transthoracic ultrasound Doppler at the level of the aortic valve, we compared blood flow velocities in the left ventricle and cardiac frequencies during rest and at 1, 3 and 4 min after a bout of exercise in 13 adult bottlenose dolphins (Tursiops truncatus, six male and seven female, body mass range 143-212 kg). Aortic cross-sectional area and ventricle blood velocity at the aortic valve were used to calculate SV, which together with fH provided estimates of left CO at rest and following exercise. fH and SV stabilized approximately 4-7 s following the post-respiratory tachycardia, so only data after the fH had stabilized were used for analysis and comparison. There were significant increases in fH, SV and CO associated with each breath. At rest, fH, SV and CO were uncorrelated with body mass, and averaged 41±9 beats min(-1), 136±19 ml and 5514±1182 l min(-1), respectively. One minute following high intensity exercise, the cardiac variables had increased by 104±43%, 63±11% and 234±84%, respectively. All variables remained significantly elevated in all animals for at least 4 min after the exercise. These baseline values provide the first data on SV and CO in awake and unrestrained cetaceans in water. PMID:26385334

  19. Cardiac output, oxygen consumption and arteriovenous oxygen difference following a sudden rise in exercise level in humans.

    PubMed Central

    De Cort, S C; Innes, J A; Barstow, T J; Guz, A

    1991-01-01

    1. To investigate the relative contributions of increases in cardiac output and arteriovenous oxygen difference to the increase in oxygen consumption during exercise, the ventilatory and cardiovascular responses to a sudden transition from unloaded cycling to 70 or 80 W were measured in six normal healthy subjects. 2. Oxygen consumption (VO2) was measured breath-by-breath and corrected for changes in lung gas stores. Cardiac output (Q) was measured beat-by-beat using pulsed Doppler ultrasound, and blood pressure was measured beat-by-beat using a non-invasive finger cuff (Finapres). All data were calculated off-line, second-by-second. 3. Arteriovenous oxygen difference (A-VO2) was calculated from Q and VO2 using the Fick Principle. Left ventricular afterload was calculated by dividing Q by mean blood pressure. 4. The data for Q and VO2 were closely fitted by single exponential curves (mean r2 0.84 and 0.90 respectively; r is the correlation coefficient). These curves yielded mean time constants for the increases in Q and VO2 of 28 and 55 s respectively following the increase in exercise level. In each individual subject, the time course of adjustment of Q was faster than that of VO2. There was a mean lag of 15 s from the start of the new exercise level before the derived A-V O2 began to increase; the mean time constant for A-V O2 was 57 s. 5. If A-V O2 had remained constant, the observed rise in Q alone would have resulted in an average of 87% of the increase in VO2 which was observed after 5 s. If Q had remained constant, the observed increase in A-V O2 would have led to only 8% of the actual increase in VO2 after 5 s. 6. Mean and systolic blood pressure rose and afterload fell immediately after the onset of the increased workload. The time constants of the systolic blood pressure and afterload responses to exercise varied widely and ranged from 37 to 81 and 10 to 26 s respectively (n = 4). 7. We conclude that Q is responsible for most of the early increase in VO2 following a sudden increase in exercise workload. Blood pressure responses to exercise are slower than Q and VO2 responses, probably due to the rapid decrease in afterload. 8. The dominant contribution of Q to adaptation to changing workload may be physiologically important particularly in heart disease, where decreased ability to increase cardiac output may limit the capacity to cope with changing metabolic needs during everyday activities. PMID:1816384

  20. The effect of intravenous epoprostenol (prostacyclin, PGI2) on cerebral blood flow and cardiac output in man.

    PubMed Central

    Cook, P J; Maidment, C G; Dandona, P; Hutton, R A; James, I M

    1983-01-01

    Epoprostenol (prostacyclin, PGI2) was given intravenously to seven healthy volunteers in a dose of 4 ng kg-1 min-1 over a 30 min period. Diastolic blood pressure fell but there was no change in cardiac output. The mean PGI2 concentration at the end of the infusion was 0.43 ng/ml (1.1 nM) and a significant inhibition of ADP-induced platelet aggregation occurred. Although obvious facial flushing occurred in all subjects and some subjects complained of headache, cerebral blood flow tended to fall. The results do not support the hypothesis that PGI2 acts as a physiological vasodilator involved in the homeostasis of normal cerebral blood flow. PMID:6362696

  1. Use of an extracorporeal arteriovenous tubing loop to measure cardiac output in intensive care unit patients by ultrasound velocity dilution.

    PubMed

    Eremenko, A; Balykov, I; Chaus, N; Kislukhin, V; Krivitski, N

    1998-01-01

    Thermodilution cardiac output (CO) measurement requires heart catheterization and is known as a risk factor. The existing cannula in the radial artery in intensive care unit (ICU) patients can be used to measure CO by ultrasound dilution (COus). An arteriovenous shunt between the radial artery and cubital vein was created using a 25 cm tubing loop. An ultrasound flow dilution sensor was clamped on the tubing and connected to a modified HD01 monitor (Transonic Systems, Inc., Ithaca, NY). Calibration injections of 1 ml 0.9% NaCl were injected into the tubing. An intravenous bolus injection consisted of 10-20 ml 0.9% NaCl. Simultaneously, CO was measured by thermal dilution (COth; MI 166A, Hewlett Packard, Andover, MA). Each value for COth or COus was based on the average of three to five injections. Blood flow through the shunt was 10 to 26 ml/min. The comparison was made on 14 patients. In 33 measurements, the regression equation was COth = -0.08 + 1.02 COus (r = 0.97). In 22 cases, the difference between COth and COus was less than 5%, in 9 cases it was in the range of 5-10%, and in 2 cases it was in the range of 10-20%. The presence of arterial and venous lines in an ICU setting obviates the need for cardiac catheterization for the determination of CO. PMID:9804473

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

    PubMed Central

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

    2013-01-01

    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. PMID:24133260

  3. Cardiac output by Doppler echocardiography in the premature baboon: Comparison with radiolabeled microspheres

    SciTech Connect

    Kinsella, J.P.; Morrow, W.R.; Gerstmann, D.R.; Taylor, A.F.; deLemos, R.A. )

    1991-04-01

    Pulsed-Doppler echocardiography (PDE) is a useful noninvasive method for determining left ventricular output (LVO). However, despite increasingly widespread use in neonatal intensive care units, validation studies in prematures with cardiopulmonary disease are lacking. The purpose of this study was to compare radiolabeled microsphere (RLM) and PDE measurements of LVO, using the critically ill premature baboon as a model of the human neonate. Twenty-two paired RLM and PDE measurements of LVO were obtained in 14 animals between 3 and 24 h of age. Average PDE LVO was 152 ml/min/kg (range, 40-258 ml/min/kg) compared to 158 ml/min/kg (range, 67-278 ml/min/kg) measured by RLM. Linear regression analysis of the paired measurements showed good correlation with a slope near unity (gamma = 0.94x + 4.20, r = 0.91, SEE = 25.7 ml). The authors conclude that PDE determinations of LVO compare well with those measured by RLM in the premature baboon. PDE appears to provide a valid estimate of LVO and should be useful in human prematures with cardiopulmonary distress.

  4. Role of cardiac output and the autonomic nervous system in the antinatriuretic response to acute constriction of the thoracic superior vena cava.

    NASA Technical Reports Server (NTRS)

    Schrier, R. W.; Humphreys, M. H.; Ufferman, R. C.

    1971-01-01

    Study of the differential characteristics of hepatic congestion and decreased cardiac output in terms of potential afferent stimuli in the antinatriuretic effect of acute thoracic inferior vena cava (TIVC) constriction. An attempt is made to see if the autonomic nervous system is involved in the antinatriuretic effect of acute TIVC or thoracic superior vena cava constriction.

  5. Reliability of a new 4th generation FloTrac algorithm to track cardiac output changes in patients receiving phenylephrine.

    PubMed

    Ji, Fuhai; Li, Jian; Fleming, Neal; Rose, David; Liu, Hong

    2015-08-01

    Phenylephrine is often used to treat intra-operative hypotension. Previous studies have shown that the FloTrac cardiac monitor may overestimate cardiac output (CO) changes following phenylephrine administration. A new algorithm (4th generation) has been developed to improve performance in this setting. We performed a prospective observational study to assess the effects of phenylephrine administration on CO values measured by the 3rd and 4th generation FloTrac algorithms. 54 patients were enrolled in this study. We used the Nexfin, a pulse contour method shown to be insensitive to vasopressor administration, as the reference method. Radial arterial pressures were recorded continuously in patients undergoing surgery. Phenylephrine administration times were documented. Arterial pressure recordings were subsequently analyzed offline using three different pulse contour analysis algorithms: FloTrac 3rd generation (G3), FloTrac 4th generation (G4), and Nexfin (nf). One minute of hemodynamic measurements was analyzed immediately before phenylephrine administration and then repeated when the mean arterial pressure peaked. A total of 157 (4.6 ± 3.2 per patient, range 1-15) paired sets of hemodynamic recordings were analyzed. Phenylephrine induced a significant increase in stroke volume (SV) and CO with the FloTrac G3, but not with FloTrac G4 or Nexfin algorithms. Agreement between FloTrac G3 and Nexfin was: 0.23 ± 1.19 l/min and concordance was 51.1%. In contrast, agreement between FloTrac G4 and Nexfin was: 0.19 ± 0.86 l/min and concordance was 87.2%. In conclusion, the pulse contour method of measuring CO, as implemented in FloTrac 4th generation algorithm, has significantly improved its ability to track the changes in CO induced by phenylephrine. PMID:25267438

  6. Differential acute effects of carbohydrate- and protein-rich drinks compared with water on cardiac output during rest and exercise in healthy young men.

    PubMed

    Rontoyanni, Victoria G; Werner, Kristin; Sanders, Thomas A B; Hall, Wendy L

    2015-08-01

    The acute effects of drinks rich in protein (PRO) versus carbohydrate (CHO) on cardiovascular hemodynamics and reactivity are uncertain. A randomized crossover design was used to compare 400-mL isoenergetic (1.1 MJ) drinks containing whey protein (PRO; 44 g) or carbohydrate (CHO; 57 g) versus 400 mL of water in 14 healthy men. The primary and secondary outcomes were changes in cardiac output, blood pressure, systemic vascular resistance (SVR) and digital volume pulse measured prior to and 30 min following consumption at rest, during 12 min of multi-stage bicycle ergometry, and 15 min postexercise. The mean change (95% confidence interval (CI)) in resting cardiac output at 30 min was greater for CHO than for PRO or water: 0.7 (0.4 to 1.0), 0.1 (-0.2 to 0.40), and 0.0 (-0.3 to 0.3) L/min (P < 0.001), respectively; the higher cardiac output following CHO was accompanied by an increase in stroke volume and a lower SVR. The mean increments (95% CI) in cardiac output during exercise were CHO 4.7 (4.4 to 5.0), PRO 4.9 (4.6 to 5.2), and water 4.6 (4.3 to 4.9) L/min with the difference between PRO versus water being significant (P < 0.025). There were no other statistically significant differences. In summary, a CHO-rich drink increased cardiac output and lowered SVR in the resting state compared with a PRO-rich drink or water but the effect size of changes in these variables did not differ during or after exercise between CHO and PRO. Neither protein nor carbohydrate affected blood pressure reactivity to exercise. PMID:26244599

  7. 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...

  8. Comparison of cardiac output of the left and right side of the heart by ultrafast computed tomography

    SciTech Connect

    Wolfkiel, C.J.; Ferguson, J.L.; Law, W.R.; Chomka, E.V.; Brundage, B.H.

    1986-03-05

    Ultrafast computed tomography (CT) evaluation of cardiac output (CO) can be determined using indicator dilution theory. The concentration of an iodinated contrast agent injected into a vein of a subject can be measured as a function of time by serial EKG, gated CT imaging. The contrast density of the blood pool measured by CT defines the indicator concentration. CT CO is proportional to the area under a time density curve from a region of the blood pool. Proper subject position and scanning timing allows CT to measure CO in the pulmonary (PA) artery and the aorta (AO) with the same contrast bolus. Three anesthetized dogs were multiply scanned following simultaneous injections of contrast and radioactive tracer microspheres. Microsphere CO was determined by reference withdrawal method. Multiple thermodilution CO measurements were made just prior and after each CT CO procedure. 24 comparisons were made of thermodilution, microsphere and CT CO measured in the PA (right sided CO (RSCO)) and the AO (left sided CO (LSCO)). CT CO was calculated as the ratio of the volume of contrast injected to the time density curve area corrected for the relation of contrast density to CT number. RSCO agreed very closely to LSCO (r = .99, p < .001; y = 1.0x +/- .32). RSCO correlated to thermodilution (r = .96, p < .001; y = 1.2x +/- 1.3) and microsphere CO (r = .93, p < .001; y = .69x +/- 1.3). These data show that CT CO measurements can be made in the PA and AO with equal accuracy.

  9. Cardiac output method comparison studies: the relation of the precision of agreement and the precision of method.

    PubMed

    Hapfelmeier, Alexander; Cecconi, Maurizio; Saugel, Bernd

    2016-04-01

    Cardiac output (CO) plays a crucial role in the hemodynamic management of critically ill patients treated in the intensive care unit and in surgical patients undergoing major surgery. In the field of cardiovascular dynamics, innovative techniques for CO determination are increasingly available. Therefore, the number of studies comparing these techniques with a reference, such as pulmonary artery thermodilution, is rapidly growing. There are mainly two outcomes of such method comparison studies: (1) the accuracy of agreement and (2) the precision of agreement. The precision of agreement depends on the precision of each method, i.e., the precision that the studied and the reference technique are able to achieve. We call this "precision of method". A decomposition of variance shows that method agreement does not only depend on the precision of method but also on another important source of variability, i.e., the method's general variability about the true values. Ignorance of that fact leads to falsified conclusions about the precision of method of the studied technique. In CO studies, serial measurements are frequently confused with repeated measurements. But as the actual CO of a subject changes from assessment to assessment, there is no real repetition of a measurement. This situation equals a scenario in which single measurements are given for multiple true values per subject. In such a case it is not possible to assess the precision of method. PMID:26026648

  10. Accuracy of cardiac output measurements during off-pump coronary artery bypass grafting: according to the vessel anastomosis sites

    PubMed Central

    Park, Sung Yong; Kim, Dae Hee; Joe, Han Bum; Yoo, Ji Young; Kim, Jin Soo; Kang, Min

    2012-01-01

    Background During beating heart surgery, the accuracy of cardiac output (CO) measurement techniques may be influenced by several factors. This study was conducted to analyze the clinical agreement among stat CO mode (SCO), continuous CO mode (CCO), arterial pressure waveform-based CO estimation (APCO), and transesophageal Doppler ultrasound technique (UCCO) according to the vessel anastomosis sites. Methods This study was prospectively performed in 25 patients who would be undergoing elective OPCAB. Hemodynamic variables were recorded at the following time points: during left anterior descending (LAD) anastomosis at 1 min and 5 min; during obtuse marginal (OM) anastomosis at 1 min and 5 min: and during right coronary artery (RCA) anastomosis at 1 min and 5 min. The variables measured including the SCO, CCO, APCO, and UCCO. Results CO measurement techniques showed different correlations according to vessel anastomosis site. However, the percent error observed was higher than the value of 30% postulated by the criteria of Critchley and Critchley during all study periods for all CO measurement techniques. Conclusions In the beating heart procedure, SCO, CCO and APCO showed different correlations according to the vessel anastomosis sites and did not agree with UCCO. CO values from the various measurement techniques should be interpreted with caution during OPCAB. PMID:22679538

  11. Methodology of method comparison studies evaluating the validity of cardiac output monitors: a stepwise approach and checklist.

    PubMed

    Montenij, L J; Buhre, W F; Jansen, J R; Kruitwagen, C L; de Waal, E E

    2016-06-01

    The validity of each new cardiac output (CO) monitor should be established before implementation in clinical practice. For this purpose, method comparison studies investigate the accuracy and precision against a reference technique. With the emergence of continuous CO monitors, the ability to detect changes in CO, in addition to its absolute value, has gained interest. Therefore, method comparison studies increasingly include assessment of trending ability in the data analysis. A number of methodological challenges arise in method comparison research with respect to the application of Bland-Altman and trending analysis. Failure to face these methodological challenges will lead to misinterpretation and erroneous conclusions. We therefore review the basic principles and pitfalls of Bland-Altman analysis in method comparison studies concerning new CO monitors. In addition, the concept of clinical concordance is introduced to evaluate trending ability from a clinical perspective. The primary scope of this review is to provide a complete overview of the pitfalls in CO method comparison research, whereas other publications focused on a single aspect of the study design or data analysis. This leads to a stepwise approach and checklist for a complete data analysis and data representation. PMID:27199309

  12. Servo Control of High Degree of Linear Polarization Output from Polarization-Maintaining Fiber and its Application in Fiber-Component Based Frequency Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ma, Weiguang; Li, Zhixin; Tan, Wei; Zhao, Gang; Fu, Xiaofang; Zhang, Lei; Dong, Lei; Yin, Wangbao; Jia, Suotang

    2013-11-01

    A novel servo control method has been developed to output a highly linear state of polarization (SOP) from a polarization-maintaining (PM) fiber. The correction signal is obtained using an SOP detection setup invented by Hänsch and Couillaud. This servo control method was then applied to fiber-component based frequency modulation spectroscopy experimentally to reduce the residual amplitude modulation (RAM) induced by nonlinear SOP incident to an electro-optic modulator. With active servo control, stable linear SOP output of PM fiber and pure frequency modulation lineshapes are obtained. Finally, long-term measurements of the dispersion background signal with feedback loop on and off are performed to evaluate the stability of RAM reduction.

  13. Roles for Cardiac MyBP-C in Maintaining Myofilament Lattice Rigidity and Prolonging Myosin Cross-Bridge Lifetime

    SciTech Connect

    Palmer, B.M.; Sadayappan, S.; Wang, Y.; Weith, A.E.; Previs, M.J.; Bekyarova, T.; Irving, T.C.; Robbins, J.; Maughan, D.W.

    2011-10-06

    We investigated the influence of cardiac myosin binding protein-C (cMyBP-C) and its constitutively unphosphorylated status on the radial and longitudinal stiffnesses of the myofilament lattice in chemically skinned myocardial strips of the following mouse models: nontransgenic (NTG), effective null for cMyBP-C (t/t), wild-type cMyBP-C expressed into t/t (WT{sub t/t}), and constitutively unphosphorylated cMyBP-C (AllP{sub -t/t}). We found that the absence of cMyBP-C in the t/t and the unphosphorylated cMyBP-C in the AllP{sub -t/t} resulted in a compressible cardiac myofilament lattice induced by rigor not observed in the NTG and WT{sub t/t}. These results suggest that the presence and phosphorylation of the N-terminus of cMyBP-C provides structural support and radial rigidity to the myofilament lattice. Examination of myofilament longitudinal stiffness under rigor conditions demonstrated a significant reduction in cross-bridge-dependent stiffness in the t/t compared with NTG controls, but not in the AllP{sub -t/t} compared with WT{sub t/t} controls. The absence of cMyBP-C in the t/t and the unphosphorylated cMyBP-C in the AllP{sub -t/t} both resulted in a shorter myosin cross-bridge lifetime when myosin isoform was controlled. These data collectively suggest that cMyBP-C provides radial rigidity to the myofilament lattice through the N-terminus, and that disruption of the phosphorylation of cMyBP-C is sufficient to abolish this structural role of the N-terminus and shorten cross-bridge lifetime. Although the presence of cMyBP-C also provides longitudinal rigidity, phosphorylation of the N-terminus is not necessary to maintain longitudinal rigidity of the lattice, in contrast to radial rigidity.

  14. Design of eight-mode polarization-maintaining few-mode fiber for multiple-input multiple-output-free spatial division multiplexing.

    PubMed

    Wang, Lixian; LaRochelle, Sophie

    2015-12-15

    We propose a polarization-maintaining few-mode fiber (FMF) that features an elliptical ring shaped core with a high refractive index contrast ∼0.03 between the core and the cladding. This fiber design alleviates the usual trade-off between the number of guided modes and the achievable birefringence that is usually observed in conventional elliptical-core FMFs. Through numerical simulations, we show that this fiber design can support up to 10 guided vector modes over the entire C band while providing large birefringence. Except for the two fundamental modes, the eight higher-order vector modes are all separated from their adjacent modes by effective index differences >10⁻⁴, which is the typical birefringence value of single-mode polarization maintaining fibers. The designed fiber targets applications in spatial division multiplexing of optical channels, without multiple-input-multiple-output (MIMO) digital signal processing, for short-reach optical interconnects. PMID:26670527

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

    PubMed Central

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

    2011-01-01

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

  16. Ultrasound cardiac output units.

    PubMed

    1988-01-01

    We evaluated 2 dedicated CO US units that calculate CO for teenage and adult ranges. We also tested a unit designed for use on neonatal to pediatric patients and discussed this device separately. Because of the limitations of US technology, we found these units to be best suited for trending CO; however, the utility of US CO for this application far outweighs its limitations. PMID:3079193

  17. Ultrasound cardiac output units.

    PubMed

    1988-12-01

    We evaluated two dedicated units that calculate CO for teenage and adult ranges. We also tested a unit designed for use on neonatal to pediatric patients and discussed this device separately. Both of the evaluated units were rated Acceptable. Because of the limitations of ultrasound (US) technology, we found these units to be best suited for trending CO; however, the utility of US CO for this application far outweighs its limitations. PMID:3273933

  18. Addressing Assumptions for the Use of Non-invasive Cardiac Output Measurement Techniques During Exercise in COPD.

    PubMed

    Perrault, Hélène; Richard, Ruddy; Kapchinsky, Sophia; Baril, Jacinthe; Bourbeau, Jean; Taivassalo, Tanja

    2016-02-01

    The multifactorial functional limitation of COPD increasingly demonstrates the need for an integrated circulatory assessment. In this study cardiac output (Qc) derived from non-inert (CO2-RB), inert (N2O-RB) gas rebreathing approaches and bioimpedance were compared to examine the limitations of currently available non-invasive techniques for exercise Qc determination in patients with chronic lung disease. Thirteen COPD patients (GOLD II-III) completed three constant cycling bouts at 20, 35, and 50% of peak work on two occasions to assess Qc with bioimpedance as well as using CO2-RB and N2O-RB for all exercise tests. Results showed significantly lower Qc using the N2O-RB or end-tidal CO2-derived Qc compared to the PaCO2-derived CO2-RB or the bioimpedance at rest and for all exercise intensities. End-tidal CO2-derived values are however not statistically different from those obtained using inert-gas rebreathing. This study show that in COPD patients, CO2-rebreathing Qc values obtained using PaCO2 contents which account for any gas exchange impairment or inadequate gas mixing are similar to those obtained using thoracic bioimpedance. Alternately, the lower values for N2O rebreathing derived Qc indicates the inability of this technique to account for gas exchange impairment in the computation of Qc. These findings indicate that the choice of a gas rebreathing technique to measure Qc in patients must be dictated by the ability to include in the derived computations a correction for either gas exchange inadequacies and/or a vascular shunt. PMID:26408087

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

    PubMed Central

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

    2013-01-01

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

  20. Drug effects on the CVS in conscious rats: separating cardiac output into heart rate and stroke volume using PKPD modelling

    PubMed Central

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

    2014-01-01

    Background and Purpose Previously, a systems pharmacology model was developed characterizing drug effects on the interrelationship between mean arterial pressure (MAP), cardiac output (CO) and total peripheral resistance (TPR). The present investigation aims to (i) extend the previously developed model by parsing CO into heart rate (HR) and stroke volume (SV) and (ii) evaluate if the mechanism of action (MoA) of new compounds can be elucidated using only HR and MAP measurements. Experimental Approach Cardiovascular effects of eight drugs with diverse MoAs (amiloride, amlodipine, atropine, enalapril, fasudil, hydrochlorothiazide, prazosin and propranolol) were characterized in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats following single administrations of a range of doses. Rats were instrumented with ascending aortic flow probes and aortic catheters/radiotransmitters for continuous recording of MAP, HR and CO throughout the experiments. Data were analysed in conjunction with independent information on the time course of the drug concentration following a mechanism-based pharmacokinetic-pharmacodynamic modelling approach. Key Results The extended model, which quantified changes in TPR, HR and SV with negative feedback through MAP, adequately described the cardiovascular effects of the drugs while accounting for circadian variations and handling effects. Conclusions and Implications A systems pharmacology model characterizing the interrelationship between MAP, CO, HR, SV and TPR was obtained in hypertensive and normotensive rats. This extended model can quantify dynamic changes in the CVS and elucidate the MoA for novel compounds, with one site of action, using only HR and MAP measurements. Whether the model can be applied for compounds with a more complex MoA remains to be established. PMID:24962208

  1. Finger arterial versus intrabrachial pressure and continuous cardiac output during head-up tilt testing in healthy subjects.

    PubMed

    Jellema, W T; Imholz, B P; van Goudoever, J; Wesseling, K H; van Lieshout, J J

    1996-08-01

    1. The aims of this study were to determine the clinical feasibility of continuous, non-invasive Finapres recordings as a replacement for intrabrachial pressure during a 30 min head-up tilt, and the reliability of continuous cardiac output computation by pulse contour analysis from the finger arterial versus the brachial waveform. 2. In eight healthy subjects a 30 min 70 degrees passive head-up tilt was performed. Finger arterial (FINAP) and intrabrachial (IAP) pressures were measured simultaneously. Beat-to-beat changes in stroke volume were computed using a pulse contour algorithm. 3. Accuracy (the group-averaged FINAP-IAP difference) and precision (the SD of the difference) of Finapres measurements were 4 and 9 mmHg for systolic blood pressure, -5 and 9 mmHg for mean blood pressure and -5 and 9mmHg for diastolic blood pressure. 4. The time course of the FINAP-IAP differences during head-up tilt showed a linear trend (P < 0.001 for all pressure levels). Averaged for the group, the difference increased 7 mmHg for mean blood pressure. The difference in stroke volume computed from FINAP and IAP was 0.3 +/- 5% (mean +/- SD), and independent of the duration of the tilt (P > 0.05). This difference did not change at low blood pressure levels (0.5 +/- 6%). 5. The qualitative performance of the Finapres allows it to be used in the clinical setting as a monitor of sudden changes in blood pressure induced by a 30 min head-up tilt. Relative changes in stroke volume, as obtained by pulse contour analysis of the finger arterial waveform, closely follow intrabrachial values during long-duration head-up tilt and associated arterial hypotension. PMID:8795443

  2. CARDIO--a Lotus 1-2-3 based computer program for rapid calculation of cardiac output from dye or thermal dilution curves.

    PubMed

    Brill, R W; Bushnell, P G

    1989-01-01

    We have developed a menu-driven computer program (CARDIO), based on a Lotus 1-2-3 template and a series of macrocommands, that rapidly and semiautomatically calculates cardiac output from dye or thermal dilution curves. CARDIO works with any dye or thermal dilution recorder with an analog output, any analog to digital (A-to-D) conversion system, and any computer capable of running Lotus 1-2-3 version 2. No prior experience with Lotus 1-2-3 is needed to operate CARDIO, but experienced users can take full advantage of Lotus 1-2-3's graphics, data manipulation, and data retrieval capabilities. PMID:2689079

  3. Early predictors of acute kidney injury in patients with cirrhosis and bacterial infection: urinary neutrophil gelatinase-associated lipocalin and cardiac output as reliable tools

    PubMed Central

    Ximenes, Rafael O.; Farias, Alberto Q.; Helou, Claudia M.B.

    2015-01-01

    Background Hemodynamic abnormalities and acute kidney injury (AKI) are often present in infected cirrhotic patients. Hence, an early diagnosis of AKI is necessary, which might require the validation of new predictors as the determinations of urinary neutrophil gelatinase-associated lipocalin (uNGAL) and cardiac output. Methods We evaluated 18 infected cirrhotic patients subdivided into two groups at admission (0 hours). In Group I, we collected urine samples at 0 hours, 6 hours, 24 hours, and 48 hours for uNGAL and fractional excretion of sodium determinations. In Group II, we measured cardiac output using echocardiography. Results The age of patients was 55.0±1.9 years, and 11 patients were males. The Model for End-Stage Liver Disease score was 21±1, whereas the Child–Pugh score was C in 11 patients and B in 7 patients. Both patients in Group I and Group II showed similar baseline characteristics. In Group I, we diagnosed AKI in 5 of 9 patients, and the mean time to this diagnosis by measuring serum creatinine was 5.4 days. Patients with AKI showed higher uNGAL levels than those without AKI from 6 hours to 48 hours. The best accuracy using the cutoff values of 68 ng uNGAL/mg creatinine was achieved at 48 hours when we distinguished patients with and without AKI in all cases. In Group II, we diagnosed AKI in 4 of 9 patients, and cardiac output was significantly higher in patients who developed AKI at 0 hours. Conclusion Both uNGAL and cardiac output determinations allow the prediction of AKI in infected cirrhotic patients earlier than increments in serum creatinine. PMID:26484038

  4. 8-Oxoguanine DNA glycosylase 1 (ogg1) maintains the function of cardiac progenitor cells during heart formation in zebrafish

    SciTech Connect

    Yan, Lifeng; Zhou, Yong; Yu, Shanhe; Ji, Guixiang; Liu, Wei; Gu, Aihua

    2013-11-15

    Genomic damage may devastate the potential of progenitor cells and consequently impair early organogenesis. We found that ogg1, a key enzyme initiating the base-excision repair, was enriched in the embryonic heart in zebrafish. So far, little is known about DNA repair in cardiogenesis. Here, we addressed the critical role of ogg1 in cardiogenesis for the first time. ogg1 mainly expressed in the anterior lateral plate mesoderm (ALPM), the primary heart tube, and subsequently the embryonic myocardium by in situ hybridisation. Loss of ogg1 resulted in severe cardiac morphogenesis and functional abnormalities, including the short heart length, arrhythmia, decreased cardiomyocytes and nkx2.5{sup +} cardiac progenitor cells. Moreover, the increased apoptosis and repressed proliferation of progenitor cells caused by ogg1 deficiency might contribute to the heart phenotype. The microarray analysis showed that the expression of genes involved in embryonic heart tube morphogenesis and heart structure were significantly changed due to the lack of ogg1. Among those, foxh1 is an important partner of ogg1 in the cardiac development in response to DNA damage. Our work demonstrates the requirement of ogg1 in cardiac progenitors and heart development in zebrafish. These findings may be helpful for understanding the aetiology of congenital cardiac deficits. - Highlights: • A key DNA repair enzyme ogg1 is expressed in the embryonic heart in zebrafish. • We found that ogg1 is essential for normal cardiac morphogenesis in zebrafish. • The production of embryonic cardiomyocytes requires appropriate ogg1 expression. • Ogg1 critically regulated proliferation of cardiac progenitor cells in zebrafish. • foxh1 is a partner of ogg1 in the cardiac development in response to DNA damage.

  5. Myozap, a novel intercalated disc protein, activates SRF-dependent signaling and is required to maintain cardiac function in vivo

    PubMed Central

    Seeger, Thalia S.; Frank, Derk; Rohr, Claudia; Will, Rainer; Just, Steffen; Grund, Christine; Lyon, Robert; Lüdde, Mark; Koegl, Manfred; Sheikh, Farah; Rottbauer, Wolfgang; Franke, Werner W.; Katus, Hugo A.; Olson, Eric N.; Frey, Norbert

    2010-01-01

    Rationale The intercalated disc (ID) is a highly specialized cell-cell contact structure that ensures mechanical and electrical coupling of contracting cardiomyocytes. Recently, the ID has been recognized to be a hot spot of cardiac disease, in particular inherited cardiomyopathy. Objective Given its complex structure and function we hypothesized that important molecular constituents of the ID still remain unknown. Methods Using a bioinformatic screen, we discovered and cloned a previously uncharacterized 54 kDa cardiac protein which we termed Myozap (Myocardium-enriched ZO-associated protein). Results Myozap is strongly expressed in the heart and lung. In cardiac tissue it localized to the ID and directly binds to desmoplakin and ZO-1. In a yeast-two hybrid screen for additional binding partners of Myozap we identified myosin phosphatase-RhoA interacting protein (MRIP), a negative regulator of Rho activity. Myozap, in turn, strongly activates SRF-dependent transcription through its ERM (Ezrin/radixin/moesin)-like domain in a Rho-dependent fashion. Finally, in vivo knockdown of the Myozap orthologue in zebrafish led to severe contractile dysfunction and cardiomyopathy. Conclusions Taken together, these findings reveal Myozap as a previously unrecognized component of a Rho-dependent signaling pathway that links the intercalated disc to cardiac gene regulation. Moreover, its subcellular localization and the observation of a severe cardiac phenotype in zebrafish, implicate Myozap in the pathogenesis of cardiomyopathy. PMID:20093627

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

    PubMed Central

    2014-01-01

    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 μg.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) = θCL x (BWi)3/4 and q0(BWi) = θq0 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. PMID:24456639

  7. Is It Possible to Maintain Consciousness and Spontaneous Ventilation with Chest Compression in the Early Phase of Cardiac Arrest?

    PubMed Central

    Oksar, Menekse; Turhanoglu, Selim

    2016-01-01

    Chest compression is important in cardiopulmonary resuscitation. However, life support algorithms do not specify when chest compression should be initiated in patients with persistent spontaneous normal breathing in the early phase after cardiac arrest. Here we describe the case of a 69-year-old man who underwent femoral bypass surgery and was extubated at the end of the procedure. After extubation, the patient's breathing pattern and respiratory rate were normal. The patient subsequently developed ventricular fibrillation, evident on two monitors. Because defibrillation was ineffective, chest compression was initiated even though the patient had spontaneous normal breathing and defensive motor reflexes, which were continued throughout resuscitation. He regained consciousness and underwent tracheal extubation without neurological sequelae on postoperative day 1. This case highlights the necessity of chest compression in the early phase of cardiac arrest. PMID:26981288

  8. Human cardiac stem cells exhibit mesenchymal features and are maintained through Akt/GSK-3{beta} signaling

    SciTech Connect

    Tateishi, Kento |; Ashihara, Eishi; Honsho, Shoken |; Takehara, Naofumi; Nomura, Tetsuyaital |; Takahashi, Tomosaburo; Ueyama, Tomomi; Yamagishi, Masaaki; Yaku, Hitoshi; Matsubara, Hiroaki |. E-mail: matsubah@koto.kpu-m.ac.jp; Oh, Hidemasa . E-mail: hidemasa@kuhp.kyoto-u.ac.jp

    2007-01-19

    Recent evidence suggested that human cardiac stem cells (hCSCs) may have the clinical application for cardiac repair; however, their characteristics and the regulatory mechanisms of their growth have not been fully investigated. Here, we show the novel property of hCSCs with respect to their origin and tissue distribution in human heart, and demonstrate the signaling pathway that regulates their growth and survival. Telomerase-active hCSCs were predominantly present in the right atrium and outflow tract of the heart (infant > adult) and had a mesenchymal cell-like phenotype. These hCSCs expressed the embryonic stem cell markers and differentiated into cardiomyocytes to support cardiac function when transplanted them into ischemic myocardium. Inhibition of Akt pathway impaired the hCSC proliferation and induced apoptosis, whereas inhibition of glycogen synthase kinase-3 (GSK-3) enhanced their growth and survival. We conclude that hCSCs exhibit mesenchymal features and that Akt/GSK-3{beta} may be crucial modulators for hCSC maintenance in human heart.

  9. Noninvasive cardiac output determined with a new method based on gas exchange measurements and carbon dioxide rebreathing: a study in animals/pigs.

    PubMed

    Gedeon, A; Krill, P; Kristensen, J; Gottlieb, I

    1992-10-01

    A system has been designed to determine cardiac output noninvasively. The system's main component is a closed breathing circuit and it measures oxygen uptake (VO2), carbon dioxide elimination (VCO2), and end-tidal CO2 partial pressure (PET). As an integral part of the system, periods of CO2 rebreathing can be automatically implemented. The CO2 partial pressure of oxygenated mixed venous blood (Pv) is obtained from the measured exponential rise of the PET value during such a CO2 rebreathing maneuver. A new method is described for estimating the pulmonary blood flow, alveolar ventilation, cardiac output (CO), and mixed venous oxygen saturation (SVO2) from PV, PET, VO2, VCO2, tidal volume, and arterial oxygen saturation. The method was evaluated in 6 anesthetized and mechanically ventilated pigs. A wide range of cardiac output, shunt fractions, and dead space to tidal volume ratios were induced by combinations of bronchoalveolar lavage, hypervolemia, hypovolemia, and variable levels of positive end-expiratory pressure (PEEP). The bias between the CO obtained with the noninvasive technique (CO L/min) and the thermodilution CO (Qt L/min) was 0.13 L/min (SD = 0.78 L/min) and the correlation was N = 64; R = 0.92; CO = 0.95*Qt + 0.38. The bias obtained for double determinations with the noninvasive CO technique was 0.3 L/min (SD = 0.5 L/min). The bias between the noninvasive estimates of Svo2 and the directly measured values was 1.1% (SD = 9.3%). For double determination with the noninvasive technique the bias was -0.9% (SD = 4.7%). It is concluded that in mechanically ventilated pigs the proposed method produces good estimates of CO and SVO2 also in the presence of significant ventilation/perfusion mismatch. PMID:1453186

  10. Comparison of cardiac power output and exercise performance in patients with left ventricular assist devices, explanted (recovered) patients, and those with moderate to severe heart failure.

    PubMed

    Jakovljevic, Djordje G; George, Robert S; Donovan, Gay; Nunan, David; Henderson, Keiran; Bougard, Robert S; Yacoub, Magdi H; Birks, Emma J; Brodie, David A

    2010-06-15

    Peak cardiac power output (CPO), as a direct measurement of overall cardiac function, has been shown to be a most powerful predictor of prognosis for patients with chronic heart failure. The present study assessed CPO and exercise performance in patients implanted with a left ventricular assist device (LVAD), those explanted due to myocardial recovery, and those with moderate to severe heart failure. Hemodynamic and respiratory gas exchange measurements were undertaken at rest and at peak graded exercise. These were performed in 54 patients-20 with moderate to severe heart failure, 18 with implanted LVADs, and 16 with explanted LVADs. At rest there was a nonsignificant difference in CPO among groups (p >0.05). Peak CPO was significantly higher in the explanted LVAD than in the heart failure and implanted LVAD groups (heart failure 1.90 +/- 0.45 W, implanted LVAD 2.37 +/- 0.55 W, explanted LVAD 3.39 +/- 0.61 W, p <0.01) as was peak cardiac output (heart failure 9.1 +/- 2.1 L/min, implanted LVAD 12.4 +/- 2.2 L/min, explanted LVD 14.6 +/- 2.9 L/min, p <0.01). Peak oxygen consumption was higher in the explanted LVAD than in the heart failure and implanted LVAD groups (heart failure 15.8 +/- 4.1 ml/kg/min, implanted LVAD 19.8 +/- 5.8 ml/kg/min, explanted LVAD 28.2 +/- 5.0 ml/kg/min, p <0.05) as was anaerobic threshold (heart failure 11.2 +/- 1.9 ml/kg/min, implanted LVAD 14.7 +/- 4.9 ml/kg/min, explanted LVAD 21.4 +/- 5.0 ml/kg/min, p <0.05). In conclusion, peak CPO differentiates well during cardiac restoration using LVADs and emphasizes the benefits of this therapy. CPO has the potential to be a key physiologic marker of heart failure severity and can guide management of patients with LVAD. PMID:20538130

  11. Seven times replacement of permanent cardiac pacemaker in 33 years to maintain adequate heart rate: a case report

    PubMed Central

    Li, Yanping; Liao, Derong; Yang, Ling

    2015-01-01

    Over the past few decades, recent developments in pacemaker technology from fixed-rate single-chamber pacemakers to dual chamber pacemakers with pacing algorithms have changed the therapeutic landscape resulting in better healthcare outcomes by improving rate response with minimal ventricular pacing. Here, we share our longest clinical experience with an elderly Chinese male patient who was diagnosed with third-degree atrioventricular (AV) block and was admitted in our hospital 33 years ago. An 85-year-old male patient from China was hospitalized due to dizziness and syncope, with an initial diagnosis revealing third-degree AV block with a heart rate of 35–40 beats per minute (bpm) along with Aase’s syndrome and primary hypertension. A single-chamber pacemaker (VVI) was implanted immediately giving the patient symptomatic relief. However, 5-year post-surgery VVI was replaced due to battery exhaustion, while the primary electrode catheter was kept in use. Few years later, the patient again complained of dizziness and re-examination revealed VVI battery debilitation due to premature battery exhaustion. Single-chamber pacemaker was again implanted via the same position of right upper chest. However, after adjusting the frequency of stimulation of the pacemaker to 70 bpm, patient had a symptomatic relief. Considering the severity of patient’s disease and knowing that cardiac dysfunction was reported previously, a tri-chamber pacemaker was chosen to take place of previous single-chamber pacemaker. For 33 years, the patient underwent 7 times replacement of pacemaker for battery exhaustion or inadequacy. We successfully performed overall seven pacemaker implantations and upgradation in an elderly Chinese patient diagnosed with third-degree AV block for 33 years. A long following up till now demonstrated no major complications with normal heart rate functioning. PMID:26734649

  12. Seven times replacement of permanent cardiac pacemaker in 33 years to maintain adequate heart rate: a case report.

    PubMed

    Hao, Yinglu; Li, Yanping; Liao, Derong; Yang, Ling

    2015-12-01

    Over the past few decades, recent developments in pacemaker technology from fixed-rate single-chamber pacemakers to dual chamber pacemakers with pacing algorithms have changed the therapeutic landscape resulting in better healthcare outcomes by improving rate response with minimal ventricular pacing. Here, we share our longest clinical experience with an elderly Chinese male patient who was diagnosed with third-degree atrioventricular (AV) block and was admitted in our hospital 33 years ago. An 85-year-old male patient from China was hospitalized due to dizziness and syncope, with an initial diagnosis revealing third-degree AV block with a heart rate of 35-40 beats per minute (bpm) along with Aase's syndrome and primary hypertension. A single-chamber pacemaker (VVI) was implanted immediately giving the patient symptomatic relief. However, 5-year post-surgery VVI was replaced due to battery exhaustion, while the primary electrode catheter was kept in use. Few years later, the patient again complained of dizziness and re-examination revealed VVI battery debilitation due to premature battery exhaustion. Single-chamber pacemaker was again implanted via the same position of right upper chest. However, after adjusting the frequency of stimulation of the pacemaker to 70 bpm, patient had a symptomatic relief. Considering the severity of patient's disease and knowing that cardiac dysfunction was reported previously, a tri-chamber pacemaker was chosen to take place of previous single-chamber pacemaker. For 33 years, the patient underwent 7 times replacement of pacemaker for battery exhaustion or inadequacy. We successfully performed overall seven pacemaker implantations and upgradation in an elderly Chinese patient diagnosed with third-degree AV block for 33 years. A long following up till now demonstrated no major complications with normal heart rate functioning. PMID:26734649

  13. 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

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

    2009-02-01

    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

  14. The ability of stroke volume variation measured by a noninvasive cardiac output monitor to predict fluid responsiveness in mechanically ventilated children.

    PubMed

    Lee, Ji Yeon; Kim, Ji Young; Choi, Chang Hyu; Kim, Hong Soon; Lee, Kyung Cheon; Kwak, Hyun Jeong

    2014-02-01

    Continuous noninvasive cardiac output monitoring (NICOM) is a clinically useful tool in the pediatric setting. This study compared the ability of stroke volume variation (SVV) measured by NICOM with that of respiratory variations in the velocity of aortic blood flow (△Vpeak) and central venous pressure (CVP) to predict of fluid responsiveness in mechanically ventilated children after ventricular septal defect repair. The study investigated 26 mechanically ventilated children after the completion of surgery. At 30 min after their arrival in an intensive care unit, a colloid solution of 10 ml/kg was administrated for volume expansion. Hemodynamic variables, including CVP, stroke volume, and △Vpeak in addition to cardiac output and SVV in NICOM were measured before and 10 min after volume expansion. The patients with a stroke volume increase of more than 15 % after volume expansion were defined as responders. The 26 patients in the study consisted of 13 responders and 13 nonresponders. Before volume expansion, △Vpeak and SVV were higher in the responders (both p values <0.001). The areas under the receiver operating characteristic curves of △Vpeak, SVV, and CVP were respectively 0.956 (95 % CI 0.885-1.00), 0.888 (95 % CI 0.764-1.00), and 0.331 (95 % CI 0.123-0.540). This study showed that SVV by NICOM and △Vpeak by echocardiography, but not CVP, reliably predicted fluid responsiveness during mechanical ventilation after ventricular septal defect repair in children. PMID:23963186

  15. Phosphodiesterase inhibitor KMUP-3 displays cardioprotection via protein kinase G and increases cardiac output via G-protein-coupled receptor agonist activity and Ca(2+) sensitization.

    PubMed

    Liu, Chung-Pin; Yeh, Jwu-Lai; Liou, Shu-Fen; Wu, Bin-Nan; Chen, Ing-Jun

    2016-02-01

    KMUP-3 (7-{2-[4-(4-nitrobenzene) piperazinyl]ethyl}-1, 3-dimethylxanthine) displays cardioprotection and increases cardiac output, and is suggested to increase cardiac performance and improve myocardial infarction. To determine whether KMUP-3 improves outcomes in hypoperfused myocardium by inducing Ca(2+) sensitization to oppose protein kinase (PK)G-mediated Ca(2+) blockade, we measured left ventricular systolic blood pressure, maximal rates of pressure development, mean arterial pressure and heart rate in rats, and measured contractility and expression of PKs/RhoA/Rho kinase (ROCK)II in beating guinea pig left atria. Hemodynamic changes induced by KMUP-3 (0.5-3.0 mg/kg, intravenously) were inhibited by Y27632 [(R)-(+)-trans-4-1-aminoethyl)-N-(4-Pyridyl) cyclohexane carboxamide] and ketanserin (1 mg/kg, intravenously). In electrically stimulated left guinea pig atria, positive inotropy induced by KMUP-3 (0.1-100μM) was inhibited by the endothelial NO synthase (eNOS) inhibitors N-nitro-l-arginine methyl ester (L-NAME) and 7-nitroindazole, cyclic AMP antagonist SQ22536 [9-(terahydro-2-furanyl)-9H-purin-6-amine], soluble guanylyl cyclase (sGC) antagonist ODQ (1H-[1,2,4] oxadiazolo[4,3-a] quinoxalin-1-one), RhoA inhibitor C3 exoenzyme, β-blocker propranolol, 5-hydroxytryptamine 2A antagonist ketanserin, ROCK inhibitor Y27632 and KMUP-1 (7-{2-[4-(2-chlorobenzene) piperazinyl]ethyl}-1, 3-dimethylxanthine) at 10μM. Western blotting assays indicated that KMUP-3 (0.1-10μM) increased PKA, RhoA/ROCKII, and PKC translocation and CIP-17 (an endogenous 17-kDa inhibitory protein) activation. In spontaneous right atria, KMUP-3 induced negative chronotropy that was blunted by 7-nitroindazole and atropine. In neonatal myocytes, L-NAME inhibited KMUP-3-induced eNOS phosphorylation and RhoA/ROCK activation. In H9c2 cells, Y-27632 (50μM) and PKG antagonist KT5823 [2,3,9,10,11,12-hexahydro-10R- methoxy-2,9-dimethyl-1-oxo-9S,12R-epoxy-1H-diindolo(1,2,3-fg:3',2',1'-kl) pyrrolo(3,4-i)(1,6)benzodiazocine-10-carboxylic acid, methyl ester] (3μM) reversed KMUP-3 (1-100μM)-induced Ca(2+)-entry blockade. GPCR agonist activity of KMUP-3 appeared opposed to KMUP-1, and increased cardiac output via Ca(2+) sensitization, and displayed cardioprotection via cyclic GMP/PKG-mediated myocardial preconditioning in animal studies. PMID:26944323

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

    NASA Technical Reports Server (NTRS)

    Shykoff, Barbara E.; Swanson, Harvey T.

    1987-01-01

    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.

  17. Estimation of cardiac output and systemic vascular resistance using a multivariate regression model with features selected from the finger photoplethysmogram and routine cardiovascular measurements

    PubMed Central

    2013-01-01

    Background Cardiac output (CO) and systemic vascular resistance (SVR) are two important parameters of the cardiovascular system. The ability to measure these parameters continuously and noninvasively may assist in diagnosing and monitoring patients with suspected cardiovascular diseases, or other critical illnesses. In this study, a method is proposed to estimate both the CO and SVR of a heterogeneous cohort of intensive care unit patients (N=48). Methods Spectral and morphological features were extracted from the finger photoplethysmogram, and added to heart rate and mean arterial pressure as input features to a multivariate regression model to estimate CO and SVR. A stepwise feature search algorithm was employed to select statistically significant features. Leave-one-out cross validation was used to assess the generalized model performance. The degree of agreement between the estimation method and the gold standard was assessed using Bland-Altman analysis. Results The Bland-Altman bias precision (1.96 times standard deviation) for CO was -0.01 2.70 L min-1 when only photoplethysmogram (PPG) features were used, and for SVR was -0.87 412 dyn.s.cm-5 when only one PPG variability feature was used. Conclusions These promising results indicate the feasibility of using the method described as a non-invasive preliminary diagnostic tool in supervised or unsupervised clinical settings. PMID:23452705

  18. Chronic reduction in cardiac output induces hypoxic signaling in larval zebrafish even at a time when convective oxygen transport is not required.

    PubMed

    Kopp, Renate; Schwerte, Thorsten; Egg, Margit; Sandbichler, Adolf Michael; Egger, Bernhard; Pelster, Bernd

    2010-09-01

    In the present study, the zebrafish breakdance mutant (bre) was used to assess the role of blood flow in development because it has been previously shown that bre larvae have a chronically reduced cardiac output as a result of ventricular contraction following only every second atrial contraction in addition to an atrial bradycardia. We confirmed a 50% reduction compared with control fish and further showed that blood flow in the caudal part of the dorsal aorta decreased by 80%. Associated with these reductions in blood flow were indications of developmental retardation in bre mutants, specifically delayed hatching, reduced cell proliferation, and a transiently decreased growth rate. Surprisingly, an increased red blood cell concentration and an earlier appearance of trunk vessels in bre larvae indicated some compensation to convective oxygen transport, although in previous studies it has been shown that zebrafish larvae at this stage obtain oxygen by bulk diffusion. In bre animals immunohistochemical analyses showed a significant increase in hypoxia inducible factor 1 (HIF)-? protein expression, comparable with wild-type larvae that were raised under hypoxic conditions. Accordingly, the expression of some hif downstream genes was affected. Furthermore, Affymetrix microarray analyses revealed a large number of genes that were differently expressed comparing control and bre larvae, and the number even increased with proceeding development. The results showed that a chronic reduction in blood flow generated hypoxic molecular signals despite partial compensation by increased oxygen carrying capacity and transiently slowed the overall development of zebrafish bre larvae. PMID:20571107

  19. Interruption of cardiac output does not affect short-term growth and metabolic rate in day 3 and 4 chick embryos.

    PubMed

    Burggren, W W; Warburton, S J; Slivkoff, M D

    2000-12-01

    The heart beat of vertebrate embryos has been assumed to begin when convective bulk transport by blood takes over from transport by simple diffusion. To test this hypothesis, we measured eye growth, cervical flexure and rates of oxygen consumption ( V(O2)) in day 3-4 chick embryos denied cardiac output by ligation of the outflow tract and compared them with those of embryos with an intact cardiovascular system. Eye diameter, used as the index for embryonic growth, increased at a rate of approximately 4.5-5 % h(-)(1) during the observation period. There was no significant difference (P>0.1) in the rate of increase in eye diameter between control (egg opened), sham-ligated (ligature present but not tied) and ligated embryos. Similarly, the normal progression of cervical flexure was not significantly altered by ligation (P>0.1). V(O2) (ml O(2 )g(-)(1 )h(-)(1)) at 38 degrees C, measured by closed respirometry, was not significantly different (P>0.1) on day 3 in sham-ligated (14.5+/-1.9 ml O(2 )g(-)(1 )h(-)(1)) and ligated 17.6+/-1.8 ml O(2 )g(-)(1 )h(-)(1)) embryos. Similarly, on day 4, V(O2) in sham-ligated and ligated embryos was statistically the same (sham-ligated 10. 5+/-2.9 ml O(2 )g(-)(1 )h(-)(1); ligated 9.7+/-2.9 ml O(2 )g(-)(1 )h(-)(1)). Expressed as a linear function of body mass (M), V(O2) in sham-ligated embryos was described by the equation V(O2)=-0.48M+24.06 (r(2)=0.36, N=18, P<0.01), while V(O2) in ligated embryos was described by the equation V(O2)=-0.53M+23.32 (r(2)=0.38, N=16, P<0.01). The regression line describing the relationship between body mass and V(O2) for pooled sham-ligated and ligated embryos (the two populations being statistically identical) was V(O2)=-0.47M+23.24. The slope of this regression line, which was significantly different from zero (r(2)=0.30, N=34, P<0.01), was similar to slopes calculated from previous studies over the same range of body mass.Collectively, these data indicate that growth and V(O2) are not dependent upon cardiac output and the convective blood flow it generates. Thus, early chick embryos join those of the zebrafish, clawed frog and axolotl in developing a heart beat and blood flow hours or days before required for convective oxygen and nutrient transport. We speculate that angiogenesis is the most likely role for the early development of a heart beat in vertebrate embryos. PMID:11076745

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

    PubMed Central

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

    2014-01-01

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

  1. Enhanced Ca²+ influx through cardiac L-type Ca²+ channels maintains the systolic Ca²+ transient in early cardiac atrophy induced by mechanical unloading.

    PubMed

    Schwoerer, A P; Neef, S; Broichhausen, I; Jacubeit, J; Tiburcy, M; Wagner, M; Biermann, D; Didié, M; Vettel, C; Maier, L S; Zimmermann, W H; Carrier, L; Eschenhagen, T; Volk, T; El-Armouche, A; Ehmke, H

    2013-12-01

    Cardiac atrophy as a consequence of mechanical unloading develops following exposure to microgravity or prolonged bed rest. It also plays a central role in the reverse remodelling induced by left ventricular unloading in patients with heart failure. Surprisingly, the intracellular Ca(2+) transients which are pivotal to electromechanical coupling and to cardiac plasticity were repeatedly found to remain unaffected in early cardiac atrophy. To elucidate the mechanisms underlying the preservation of the Ca(2+) transients, we investigated Ca(2+) cycling in cardiomyocytes from mechanically unloaded (heterotopic abdominal heart transplantation) and control (orthotopic) hearts in syngeneic Lewis rats. Following 2 weeks of unloading, sarcoplasmic reticulum (SR) Ca(2+) content was reduced by ~55 %. Atrophic cardiac myocytes also showed a much lower frequency of spontaneous diastolic Ca(2+) sparks and a diminished systolic Ca(2+) release, even though the expression of ryanodine receptors was increased by ~30 %. In contrast, current clamp recordings revealed prolonged action potentials in endocardial as well as epicardial myocytes which were associated with a two to fourfold higher sarcolemmal Ca(2+) influx under action potential clamp. In addition, Cav1.2 subunits which form the pore of L-type Ca(2+) channels (LTCC) were upregulated in atrophic myocardium. These data suggest that in early cardiac atrophy induced by mechanical unloading, an augmented sarcolemmal Ca(2+) influx through LTCC fully compensates for a reduced systolic SR Ca(2+) release to preserve the Ca(2+) transient. This interplay involves an electrophysiological remodelling as well as changes in the expression of cardiac ion channels. PMID:23842739

  2. Auditory stimulation of opera music induced prolongation of murine cardiac allograft survival and maintained generation of regulatory CD4+CD25+ cells

    PubMed Central

    2012-01-01

    Background Interactions between the immune response and brain functions such as olfactory, auditory, and visual sensations are likely. This study investigated the effect of sounds on alloimmune responses in a murine model of cardiac allograft transplantation. Methods Naïve CBA mice (H2k) underwent transplantation of a C57BL/6 (B6, H2b) heart and were exposed to one of three types of music--opera (La Traviata), classical (Mozart), and New Age (Enya)--or one of six different single sound frequencies, for 7 days. Additionally, we prepared two groups of CBA recipients with tympanic membrane perforation exposed to opera for 7 days and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment). An adoptive transfer study was performed to determine whether regulatory cells were generated in allograft recipients. Immunohistochemical, cell-proliferation, cytokine, and flow cytometry assessments were also performed. Results CBA recipients of a B6 cardiac graft that were exposed to opera music and Mozart had significantly prolonged allograft survival (median survival times [MSTs], 26.5 and 20 days, respectively), whereas those exposed to a single sound frequency (100, 500, 1000, 5000, 10,000, or 20,000 Hz) or Enya did not (MSTs, 7.5, 8, 9, 8, 7.5, 8.5 and 11 days, respectively). Untreated, CBA mice with tympanic membrane perforations and CBA recipients exposed to opera for 7 days before transplantation (pre-treatment) rejected B6 cardiac grafts acutely (MSTs, 7, 8 and 8 days, respectively). Adoptive transfer of whole splenocytes, CD4+ cells, or CD4+CD25+ cells from opera-exposed primary allograft recipients resulted in significantly prolonged allograft survival in naive secondary recipients (MSTs, 36, 68, and > 100 days, respectively). Proliferation of splenocytes, interleukin (IL)-2 and interferon (IFN)-γ production was suppressed in opera-exposed mice, and production of IL-4 and IL-10 from opera-exposed transplant recipients increased compared to that from splenocytes of untreated recipients. Flow cytometry studies showed an increased CD4+CD25+ Forkhead box P3 (Foxp3)+ cell population in splenocytes from those mice. Conclusion Our findings indicate that exposure to opera music, such as La traviata, could affect such aspects of the peripheral immune response as generation of regulatory CD4+CD25+ cells and up-regulation of anti-inflammatory cytokines, resulting in prolonged allograft survival. PMID:22445281

  3. Cardiac gated ventilation

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

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

  4. Pulse transit time measured by photoplethysmography improves the accuracy of heart rate as a surrogate measure of cardiac output, stroke volume and oxygen uptake in response to graded exercise.

    PubMed

    Pollonini, L; Padhye, N S; Re, R; Torricelli, A; Simpson, R J; Dacso, C C

    2015-05-01

    Heart rate (HR) is a valuable and widespread measure for physical training programs, although its description of conditioning is limited to the cardiac response to exercise. More comprehensive measures of exercise adaptation include cardiac output (Q̇), stroke volume (SV) and oxygen uptake (V̇O2), but these physiological parameters can be measured only with cumbersome equipment installed in clinical settings. In this work, we explore the ability of pulse transit time (PTT) to represent a valuable pairing with HR for indirectly estimating Q̇, SV and V̇O2 non-invasively. PTT was measured as the time interval between the peak of the electrocardiographic (ECG) R-wave and the onset of the photoplethysmography (PPG) waveform at the periphery (i.e. fingertip) with a portable sensor. Fifteen healthy young subjects underwent a graded incremental cycling protocol after which HR and PTT were correlated with Q̇, SV and V̇O2 using linear mixed models. The addition of PTT significantly improved the modeling of Q̇, SV and V̇O2 at the individual level ([Formula: see text] for SV, 0.548 for Q̇, and 0.771 for V̇O2) compared to predictive models based solely on HR ([Formula: see text] for SV, 0.503 for Q̇, and 0.745 for V̇O2). While challenges in sensitivity and artifact rejection exist, combining PTT with HR holds potential for development of novel wearable sensors that provide exercise assessment largely superior to HR monitors. PMID:25856085

  5. Cardiac arrest due to a missed diagnosis of Boerhaave's syndrome.

    PubMed

    Davies, Jennifer; Spitzer, David; Phylactou, Maria; Glasser, Martin

    2016-01-01

    A 91-year-old presented with a rare cause of cardiac arrest. He was initially admitted with severe back pain following vomiting and diagnosed with probable aspiration pneumonia. On day 3 of admission, he was discovered in cardiac arrest and cardiopulmonary resuscitation was started. On intubation, a left-sided pneumothorax and subcutaneous emphysema were noted. Needle decompression showed gastric fluid leaking from the cannula. The patient regained a cardiac output, and a subsequent CT scan confirmed a large pneumomediastinum with air tracking to the neck and chest, and bilateral pneumothoraces. A diagnosis of Boerhaave's syndrome was made. The patient was transferred to the intensive care unit but did not survive. This case demonstrates the importance of looking for and treating the rarer reversible causes of cardiac arrest, and of maintaining a high index of suspicion for Boerhaave's syndrome. Despite its rarity, Boerhaave's syndrome is often misdiagnosed on initial presentation, leading to delayed treatment and poor outcomes. PMID:27154984

  6. Comprehensible Output?

    ERIC Educational Resources Information Center

    Krashen, Stephen

    1998-01-01

    Discusses the comprehensible output (CO) hypothesis, which states that we acquire language when we attempt to transmit a message to a conversation partner, fail, try again, and eventually arrive at the correct form of the utterance. Examines weaknesses of the CO hypothesis in second language acquisition, suggesting that providing more…

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

    PubMed Central

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

    2012-01-01

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

  8. Cardiac Rehabilitation

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Cardiac Rehabilitation? Cardiac rehabilitation (rehab) is a medically supervised program ... be designed to meet your needs. The Cardiac Rehabilitation Team Cardiac rehab involves a long-term commitment ...

  9. The effect of age on the relationship between cardiac and vascular function

    PubMed Central

    Houghton, David; Jones, Thomas W.; Cassidy, Sophie; Siervo, Mario; MacGowan, Guy A.; Trenell, Michael I.; Jakovljevic, Djordje G.

    2016-01-01

    Age-related changes in cardiac and vascular function are associated with increased risk of cardiovascular mortality and morbidity. The aim of the present study was to define the effect of age on the relationship between cardiac and vascular function. Haemodynamic and gas exchange measurements were performed at rest and peak exercise in healthy individuals. Augmentation index was measured at rest. Cardiac power output, a measure of overall cardiac function, was calculated as the product of cardiac output and mean arterial blood pressure. Augmentation index was significantly higher in older than younger participants (27.7 ± 10.1 vs. 2.5 ± 10.1%, P < 0.01). Older people demonstrated significantly higher stroke volume and mean arterial blood pressure (P < 0.05), but lower heart rate (145 ± 13 vs. 172 ± 10 beats/min, P < 0.01) and peak oxygen consumption (22.5 ± 5.2 vs. 41.2 ± 8.4 ml/kg/min, P < 0.01). There was a significant negative relationship between augmentation index and peak exercise cardiac power output (r = −0.73, P = 0.02) and cardiac output (r = −0.69, P = 0.03) in older participants. Older people maintain maximal cardiac function due to increased stroke volume. Vascular function is a strong predictor of overall cardiac function in older but in not younger people. PMID:26590322

  10. The role of cardiac sympathetic innervation and skin thermoreceptors on cardiac responses during heat stress.

    PubMed

    Shibasaki, Manabu; Umemoto, Yasunori; Kinoshita, Tokio; Kouda, Ken; Ito, Tomoyuki; Nakamura, Takeshi; Crandall, Craig G; Tajima, Fumihiro

    2015-06-01

    The mechanism(s) for the changes in cardiac function during heat stress remain unknown. This study tested two unique hypotheses. First, sympathetic innervation to the heart is required for increases in cardiac systolic function during heat stress. This was accomplished by comparing responses during heat stress between paraplegics versus tetraplegics, with tetraplegics having reduced/absent cardiac sympathetic innervation. Second, stimulation of skin thermoreceptors contributes to cardiovascular adjustments that occur during heat stress in humans. This was accomplished by comparing responses during leg only heating between paraplegic versus able-bodied individuals. Nine healthy able-bodied, nine paraplegics, and eight tetraplegics participated in this study. Lower body (i.e., nonsensed area for para/tetraplegics) was heated until esophageal temperature had increased by ~1.0°C. Echocardiographic indexes of diastolic and systolic function were performed before and at the end of heat stress. The heat stress increased cardiac output in all groups, but the magnitude of this increase was attenuated in the tetraplegics relative to the able-bodied (1.3 ± 0.4 vs. 2.3 ± 1.0 l/min; P < 0.05). Diastolic function was maintained in all groups. Indexes of left atrial and ventricular systolic function were enhanced in the able-bodied, but did not change in tetraplegics, while these changes in paraplegics were attenuated relative to the able-bodied. These data suggest that the cardiac sympathetic innervation is required to achieve normal increases in cardiac systolic function during heat stress but not required to maintain diastolic function during this exposure. Second, elevated systolic function during heat stress primarily occurs as a result of increases in internal temperature, although stimulation of skin thermoreceptors may contribute. PMID:25795714

  11. Ventilation and gas exchange management after cardiac arrest.

    PubMed

    Sutherasan, Yuda; Raimondo, Pasquale; Pelosi, Paolo

    2015-12-01

    For several decades, physicians had integrated several interventions aiming to improve the outcomes in post-cardiac arrest patients. However, the mortality rate after cardiac arrest is still as high as 50%. Post-cardiac arrest syndrome is associated with high morbidity and mortality due to not only poor neurological outcome and cardiovascular failure but also respiratory dysfunction. To minimize ventilator-associated lung injury, protective mechanical ventilation by using low tidal volume ventilation and driving pressure may decrease pulmonary complications and improve survival. Low level of positive end-expiratory pressure (PEEP) can be initiated and titrated with careful cardiac output and respiratory mechanics monitoring. Furthermore, optimizing gas exchange by avoiding hypoxia and hyperoxia as well as maintaining normocarbia may improve neurological and survival outcome. Early multidisciplinary cardiac rehabilitation intervention is recommended. Minimally invasive monitoring techniques, that is, echocardiography, transpulmonary thermodilution method measuring extravascular lung water, as well as transcranial Doppler ultrasound, might be useful to improve appropriate management of post-cardiac arrest patients. PMID:26670813

  12. Cardiac Catheterization

    MedlinePlus

    ... from the NHLBI on Twitter. What Is Cardiac Catheterization? Cardiac catheterization (KATH-eh-ter-ih-ZA-shun) is a ... disease. Doctors also can use ultrasound during cardiac catheterization to see blockages in the coronary arteries. Ultrasound ...

  13. Cardiac innervation and sudden cardiac death.

    PubMed

    Fukuda, Keiichi; Kanazawa, Hideaki; Aizawa, Yoshiyasu; Ardell, Jeffrey L; Shivkumar, Kalyanam

    2015-06-01

    Afferent and efferent cardiac neurotransmission via the cardiac nerves intricately modulates nearly all physiological functions of the heart (chronotropy, dromotropy, lusitropy, and inotropy). Afferent information from the heart is transmitted to higher levels of the nervous system for processing (intrinsic cardiac nervous system, extracardiac-intrathoracic ganglia, spinal cord, brain stem, and higher centers), which ultimately results in efferent cardiomotor neural impulses (via the sympathetic and parasympathetic nerves). This system forms interacting feedback loops that provide physiological stability for maintaining normal rhythm and life-sustaining circulation. This system also ensures that there is fine-tuned regulation of sympathetic-parasympathetic balance in the heart under normal and stressed states in the short (beat to beat), intermediate (minutes to hours), and long term (days to years). This important neurovisceral/autonomic nervous system also plays a major role in the pathophysiology and progression of heart disease, including heart failure and arrhythmias leading to sudden cardiac death. Transdifferentiation of neurons in heart failure, functional denervation, cardiac and extracardiac neural remodeling has also been identified and characterized during the progression of disease. Recent advances in understanding the cellular and molecular processes governing innervation and the functional control of the myocardium in health and disease provide a rational mechanistic basis for the development of neuraxial therapies for preventing sudden cardiac death and other arrhythmias. Advances in cellular, molecular, and bioengineering realms have underscored the emergence of this area as an important avenue of scientific inquiry and therapeutic intervention. PMID:26044253

  14. [Cardiac neuroses].

    PubMed

    Simson, U; Martin, K; Janssen, P L

    2001-09-01

    Cardiac neurosis is defined as heart complaints for which no organic cause can be found. Other common terms are "cardiac anxiety neurosis", "cardiac anxiety disorder", "cardiac phobia", "functional heart complaints" and "somatoform autonomous functional disorders of the cardiovascular system" (ICD-10). Although cardiac neurosis is rarely diagnosed, it is estimated that approximately 30 bis 40% of patients with cardiovascular disorders are actually suffering from functional complaints. Predisposing to the development of cardiac neurosis are insufficient internalization processes during childhood, leading to an insoluble autonomy dependency conflict. Cardiac neurosis is treated with drugs and psychotherapy. PMID:11554103

  15. Overload protection circuit for output driver

    DOEpatents

    Stewart, Roger G.

    1982-05-11

    A protection circuit for preventing excessive power dissipation in an output transistor whose conduction path is connected between a power terminal and an output terminal. The protection circuit includes means for sensing the application of a turn on signal to the output transistor and the voltage at the output terminal. When the turn on signal is maintained for a period of time greater than a given period without the voltage at the output terminal reaching a predetermined value, the protection circuit decreases the turn on signal to, and the current conduction through, the output transistor.

  16. Cardiac arrest

    MedlinePlus

    Sudden cardiac arrest, SCA; Cardiopulmonary arrest; Circulatory arrest ... While some people refer to a heart attack as a cardiac arrest, they are not the same thing. A heart attack occurs when a blocked artery stops the flow ...

  17. Cardiac rehabilitation

    MedlinePlus

    Cardiac rehabilitation (rehab) is a program that helps you live better with heart disease. It is often prescribed to ... Ades PA, et al. Core Components of Cardiac Rehabilitation/Secondary Prevention Programs: 2007 Update: A Scientific Statement ...

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

    PubMed Central

    2012-01-01

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

  19. Comparison Between Phenylephrine and Dopamine in Maintaining Cerebral Oxygen Saturation in Thoracic Surgery: A Randomized Controlled Trial.

    PubMed

    Choi, Ji Won; JooAhn, Hyun; Yang, Mikyung; Kim, Jie Ae; Lee, Sangmin M; Ahn, Jin Hee

    2015-12-01

    Fluid is usually restricted during thoracic surgery, and vasoactive agents are often administered to maintain blood pressure. One-lung ventilation (OLV) decreases arterial oxygenation; thus oxygen delivery to the brain can be decreased. In this study, we compared phenylephrine and dopamine with respect to maintaining cerebral oxygenation during OLV in major thoracic surgery.Sixty-three patients undergoing lobectomies were randomly assigned to the dopamine (D) or phenylephrine (P) group. The patients' mean arterial pressure was maintained within 20% of baseline by a continuous infusion of dopamine or phenylephrine. Maintenance fluid was kept at 5 mL/kg/h. The depth of anesthesia was maintained with desflurane 1MAC and remifentanil infusion under bispectral index guidance. Regional cerebral oxygen saturation (rScO2) and hemodynamic variables were recorded using near-infrared spectroscopy and esophageal cardiac Doppler.The rScO2 was higher in the D group than the P group during OLV (OLV 60 min: 71 ± 6% vs 63 ± 12%; P = 0.03). The number of patients whose rScO2 dropped more than 20% from baseline was 0 and 6 in the D and P groups, respectively (P = 0.02). The D group showed higher cardiac output, but lower mean arterial pressure than the P group (4.7 ± 1.0 vs 3.9 ± 1.2 L/min; 76.7 ± 8.1 vs 84.5 ± 7.5 mm Hg; P = 0.02, P = 0.02). Among the variables, age, hemoglobin concentration, and cardiac output were associated with rScO2 by correlation analysis.Dopamine was superior to phenylephrine in maintaining cerebral oxygenation during OLV in thoracic surgery. PMID:26656357

  20. Changes in caridac output and hemolymph flow during hypoxic exposure in the gravid grass shrimp, Palaemonetes pugio.

    PubMed

    Guadagnoli, Jutta A; Reiber, Carl L

    2005-07-01

    The cardiovascular response of decapod crustaceans to hypoxic exposure is well documented; however, information is limited concerning the influence of reproductive state on cardiovascular demands during hypoxic exposure. Given the additional metabolic demand of reproduction, we investigated the cardiovascular adjustments employed by gravid grass shrimp Palaemonetes pugio to maintain oxygen delivery during hypoxic stress. Cardiac output values were elevated in gravid compared to nongravid grass shrimp. Gravid grass shrimp were exposed to hypoxia and the stroke volume, heart rate, cardiac output and hemolymph flow were determined using video-microscopy and dimensional analysis. Oxygen consumption rates were determined using respirometry. There where no changes in the cardiac output values of gravid females until reaching 6.8 kPa O2, with a significant redistribution of hemolymph flow at 13.7 kPa O2. Flow was significantly decreased to the anterior lateral arteries that supply the ovaries and hepatopancreas, the anterior aorta and the posterior aorta. The redistribution of hemolymph flow away from these vessels results in an enhanced hemolymph flow to the sternal artery that supplies the ventral segmental system, the gills, the buccal apparatus and the ventral nerve cord. The data suggest that during hypoxic stress, gravid females place a priority on survival. PMID:15891889

  1. IMPROVING CARDIAC FUNCTION WITH NEW GENERATION PLASMA VOLUME EXPANDERS

    PubMed Central

    Chatpun, Surapong; Nacharaju, Parimala; Cabrales, Pedro

    2012-01-01

    Background Plasma expander (PE) based on polyethylene glycol (PEG) conjugated to albumin has shown positive results maintaining blood volume (BV) during hemodilution and restoring BV during resuscitation from hemorrhagic shock. PEG conjugation to human serum albumin (HSA), PEG-HSA, increasing size, weigh and colloidal osmotic pressure (COP), with minor effects on solution viscosity. Methods This study was designed to test the hypothesis that PEG-HSA (2 g/dL) produced by direct PEGylation chemistry improves cardiac function during two experimental models, i) moderate hemodilution and ii) resuscitation from hemorrhagic shock, compared to a conventional colloidal plasma expander (dextran 70 kDa, D70, 6 g/dL). Cardiac function was studied using a miniaturized pressure volume (PV) conductance catheter implanted in the left ventricle (LV) and evaluated in terms of cardiac indices derived from the PV measurements. Results PEG-HSA increased cardiac output (CO), stroke volume (SV) and stroke work (SW), and decreased systemic vascular resistance (SVR) compared to D70, in both experimental models. The improvements induced by PEG-HSA in cardiac function were sustained over the observation time. PEG-HSA cardiac mechanoenergetics changes are the result of increased energy transferred per stroke, and decreased resistance of the vasculature connecting the heart. In summary, PEG-HSA decreased LV ejection impedance. Conclusion Ejection of blood diluted with PEG-HSA presented a reduced load to the heart, increased contractile function, and lowered the energy consumed per unit volume compared to D70. Our results emphasize the importance of heart function as a parameter to be included in the evaluation changes induced by new PEs. PMID:22867830

  2. Cardiac metastases

    PubMed Central

    Bussani, R; De‐Giorgio, F; Abbate, A; Silvestri, F

    2007-01-01

    Tumours metastatic to the heart (cardiac metastases) are among the least known and highly debated issues in oncology, and few systematic studies are devoted to this topic. Although primary cardiac tumours are extremely uncommon (various postmortem studies report rates between 0.001% and 0.28%), secondary tumours are not, and at least in theory, the heart can be metastasised by any malignant neoplasm able to spread to distant sites. In general, cardiac metastases are considered to be rare; however, when sought for, the incidence seems to be not as low as expected, ranging from 2.3% and 18.3%. Although no malignant tumours are known that diffuse preferentially to the heart, some do involve the heart more often than others—for example, melanoma and mediastinal primary tumours. This paper attempts to review the pathophysiology of cardiac metastatic disease, epidemiology and clinical presentation of cardiac metastases, and pathological characterisation of the lesions. PMID:17098886

  3. Redox Control of Cardiac Excitability

    PubMed Central

    Aggarwal, Nitin T.

    2013-01-01

    Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

  4. Adding Emulsified Isoflurane to Cardioplegia Solution Produces Cardiac Protection in a Dog Cardiopulmonary Bypass Model

    PubMed Central

    Huang, Han; Zhou, Cheng; Liu, Jin; Song, Haibo; Qiu, Yan

    2016-01-01

    This study investigated whether caridoplegia solution with Emulsified Isoflurane (EI) could improve cardiaoprotection in a dog CPB model of great similarity to clinical settings. Adult dogs were randomly assigned to receive one of the following cardioplegia solutions: St. Thomas with EI (group ST+EI), St. Thomas with 30% Intralipid (group ST+EL) and St. Thomas alone (group ST). The aorta was cross-clamped for two hours followed by reperfusion for another two hours, during which cardiac output was measured and dosages of positive inotropic agent to maintain normal hemodynamics were recorded. Serum level of cardiac troponin I (cTnI) and CK-MB were measured. Deletion of cardiac mitochondrial DNA was examined at the end of reperfusion. Compared with ST, ST+EI decreased the requirement of dopamine support while animals receiving ST+EI had a significantly larger cardiac output. ST+EI reduced post-CPB release of cTnI and CK-MB. Mitochondrial DNA loss was observed in only one of the tested animals from group ST+EI while it was seen in all the tested animals from group ST+EL and ST. Addition of emulsified isoflurane into cardioplegia solution protects against myocardial ischemia reperfusion injury. This protective effect might be mediated by preserving mitochondrial ultrastructure and DNA integrity. PMID:27121996

  5. Fetal cardiac function in intrauterine growth retardation.

    PubMed

    Rizzo, G; Arduini, D

    1991-10-01

    Blood-flow velocity waveforms are altered in several peripheral vascular beds of fetuses whose intrauterine growth is retarded because of placental insufficiency. We investigated these concomitant changes in cardiac function. Color and pulsed Doppler echocardiographic recordings were performed in 124 fetuses with intrauterine growth retardation. These fetuses were free of structural and chromosomal abnormalities and were characterized by increased umbilical artery resistance and reduced middle cerebral artery resistance. Twenty-four of these fetuses were also studied at weekly intervals until the onset of antepartum late heart rate decelerations. Blood-flow velocity waveforms were obtained from the aortic and pulmonary valves, and the following variables were measured: peak systolic velocity, time to peak velocity, the product of time velocity integral multiplied by heart rate, left and right cardiac output, and the right/left ratios of the product of time velocity integrals multiplied by heart rate and cardiac output. When compared with previously established norms, both aortic and pulmonary peak systolic velocities and pulmonary time to peak velocity were reduced; aortic time to peak velocity increased. Left cardiac output and the product of the aortic time velocity integral multiplied by the heart rate increased and right cardiac output and the product of the pulmonary time velocity integral multiplied by the heart rate decreased, resulting in reduced right/left ratios. In the 24 fetuses studied longitudinally, time to peak velocities and the right/left flow ratios remained stable. However, aortic and pulmonary peak velocities and cardiac output declined significantly in contrast to an expected rise with advancing gestation. The fall in cardiac output and aortic and pulmonary peak velocities was directly related to umbilical artery pH at birth. This study provides evidence of a modified cardiac function that seems to deteriorate progressively with the advancing gestation of fetuses with intrauterine growth retardation. PMID:1951546

  6. 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 ...

  7. Cardiac Sarcoidosis

    MedlinePlus

    ... do at National Jewish Health? We provide comprehensive cardiology evaluation and consultation and non-invasive cardiac testing. ... the whole person, not just the disease. Our cardiology team works with healthcare providers from all areas ...

  8. Cardiac CT

    MedlinePlus

    ... type of CT scan is called a coronary CT angiography (an-je-OG-rah-fee), or CTA. Overview ... called atrial fibrillation (AF). The pictures that cardiac CT creates of the pulmonary veins can help guide procedures used to treat ...

  9. Cardiac Catheterization

    MedlinePlus

    ... done during a cardiac catheterization include: closing small holes inside the heart repairing leaky or narrow heart ... bandage. It's normal for the site to be black and blue, red, or slightly swollen for a ...

  10. 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 ...

  11. Cardiac cephalgia.

    PubMed

    Torres-Yaghi, Yasar; Salerian, Justin; Dougherty, Carrie

    2015-04-01

    "Cardiac cephalgia" is a type of secondary headache disorder, usually initiated by exertion that is related to myocardial ischemia. Primary exertional headaches such as sex-, cough-, or exercise-induced headaches are typically benign. Cardiac cephalgia, on the other hand, can have life-threatening complications. Due to overlapping features and similarities in presentation, cardiac cephalgia can be misdiagnosed as a primary headache disorder such as migraine. However, the management of these conditions is unique, and treatment of cardiac cephalgia with vasoconstrictors intended for migraine can potentially worsen myocardial ischemia. Thus, it is important to make the correct diagnosis by evaluating cardiac function with an electrocardiogram and/or stress testing. In this review, we examine reported cases of cardiac cephalgia from the past 5 years to highlight the importance of this condition in the differential diagnosis of a headache in a patient with a history of cardiovascular risk factors, as well as to discuss the appropriate approach to diagnosis and the proposed pathogenic mechanisms of this condition. PMID:25819974

  12. Intracisternal naloxone and cardiac nerve blockade prevent vasodilatation during simulated haemorrhage in awake rabbits.

    PubMed Central

    Evans, R G; Ludbrook, J; Potocnik, S J

    1989-01-01

    1. Acute haemorrhage was simulated in five unanaesthetized rabbits, by inflating a cuff on the inferior vena cava so that cardiac output fell by 8.3% of its resting level per minute. Simulated haemorrhage was performed after sham treatment, after graded doses of intravenous and intracisternal naloxone, and after cardiac nerve blockade with intrapericardial procaine. 2. After sham treatment, the haemodynamic response to simulated haemorrhage was biphasic. During the first phase, systemic vascular conductance fell steadily, heart rate rose steadily, and arterial pressure fell only slightly. A second decompensatory phase began abruptly when cardiac output had fallen to approximately 55% of its resting level. Vascular conductance rose steeply, heart rate fell slowly, and arterial pressure fell precipitately. 3. Treatment with naloxone (intravenous, 0.04-0.4 mg kg-1; intracisternal, 0.2-2 micrograms kg-1) did not affect either phase of the haemodynamic response to simulated haemorrhage. 4. After treatment with larger doses of naloxone (intravenous, 4-8 mg kg-1; intracisternal, 4-69 micrograms kg-1), the first phase was unaffected, but the second phase no longer occurred. Throughout simulated haemorrhage, systemic vascular conductance fell steadily, heart rate rose, and arterial pressure was well maintained. The dose of intracisternal naloxone which prevented the second phase was 90-900 times less than the corresponding intravenous dose. The second phase was also prevented by cardiac nerve blockade. 5. We conclude that an endogenous opiate mechanism is responsible for the haemodynamic decompensation that occurs when cardiac output falls to a critical level. The mechanism is located within the central nervous system. It is triggered by a signal from the heart. PMID:2585286

  13. Polarization-maintaining property of tapered polarization-maintaining fibers.

    PubMed

    Wang, Xiaozhen; Niedermayer, Graeme; Lin, Ganbin; Lu, Ping; Wang, Baishi; Chen, Liang; Bao, Xiaoyi

    2013-03-10

    Distributed group birefringence of tapered polarization-maintaining fibers (PMFs) is measured by employing a high-resolution optical frequency-domain reflectometry system. Autocorrelation data processing reveals distributed mode coupling between the fast and slow modes and higher-order modes excited by the tapering process along the taper region. The polarization-maintaining property of a tapered PMF is examined by distributed group birefringence along the tapered PMF with a spatial resolution of ~1.25 cm and a polarization-extinction ratio at the fiber taper output over the wavelength range of 1510-1570 nm. With a waist diameter of 80 μm, the polarization state of the launched light is maintained and the birefringence of the tapered PMF is slightly reduced from 3.28×10(-4) to 2.89×10(-4) at the taper waist. For both the waist diameters of 60 and 40 μm, mode coupling is observed in the form of significantly decreased birefringence by a factor of ~10 at the taper waists. PMID:23478756

  14. Cardiac catheterization and angiography, 3d Ed

    SciTech Connect

    Grossman, W.

    1986-01-01

    This textbook was first published in 1974 and subsequently revised in 1980. The current edition, in seven parts and 33 chapters, has been extensively rewritten, and new chapters have been added that present recently developed techniques. The references have been updated to 1985. The purpose of this work is to provide a concise description of the major techniques employed in cardiac catheterization and angiography. Part 1 deals with the history, general principles, and practice of cardiac catheterization and angiography. In part 2, various techniques of cardiac catheterization are discussed and compared. In part 3, techniques for the determination of cardiac output, pressure, resistance, valve area, and shunt flow are described. Part 4 deals briefly with coronary angiography, cardiac ventriculography, pulmonary angiography, and aortography. In part 5, techniques for evaluating cardiac function and intracardiac electrophysiology are presented. The characteristic hemodynamic and angiographic abnormalities in specific disorders are described in part 6. Part 7 deals with special catheter techniques.

  15. Hard copy output technologies

    SciTech Connect

    Herzog, D.G.

    1987-01-01

    This book contains the proceedings from the January 13-14, 1987 conference sponsored by SPIE - The International Society for Optical Engineering. The four sessions covered the following topics: Electronic Printing and Hard Copy Output Technologies; Recording and Printing Media; Hard Copy Output Technologies - Business Graphics; and High Resolution Printing and Recording Systems. Eighteen papers are presented in this volume.

  16. Cardiac sarcoidosis

    PubMed Central

    Smedema, J.P.; Zondervan, P.E.; van Hagen, P.; ten Cate, F.J.; Bresser, P.; Doubell, A.F.; Pattynama, P.; Hoogsteden, H.C.; Balk, A.H.M.M.

    2002-01-01

    Sarcoidosis is a multi-system granulomatous disorder of unknown aetiology. Symptomatic cardiac involvement occurs in approximately 5% of patients. The prevalence of sarcoidosis in the Netherlands is unknown, but estimated to be approximately 20 per 100,000 population (3200 patients). We report on five patients who presented with different manifestations of cardiac sarcoidosis, and give a brief review on the current management of this condition. Magnetic Resonance Imaging (MRI) can be of great help in diagnosing this condition as well as in the follow-up of the response to therapy. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6 PMID:25696121

  17. Heterozygous deletion of sarcolipin maintains normal cardiac function.

    PubMed

    Shimura, Daisuke; Kusakari, Yoichiro; Sasano, Tetsuo; Nakashima, Yasuhiro; Nakai, Gaku; Jiao, Qibin; Jin, Meihua; Yokota, Tomohiro; Ishikawa, Yoshihiro; Nakano, Atsushi; Goda, Nobuhito; Minamisawa, Susumu

    2016-01-01

    Sarcolipin (SLN) is a small proteolipid and a regulator of sarco(endo)plasmic reticulum Ca(2+)-ATPase. In heart tissue, SLN is exclusively expressed in the atrium. Previously, we inserted Cre recombinase into the endogenous SLN locus by homologous recombination and succeeded in generating SLN-Cre knockin (Sln(Cre/+)) mice. This Sln(Cre/+) mouse can be used to generate an atrium-specific gene-targeting mutant, and it is based on the Cre-loxP system. In the present study, we used adult Sln(Cre/+) mice atria and analyzed the effects of heterozygous SLN deletion by Cre knockin before use as the gene targeting mouse. Both SLN mRNA and protein levels were decreased in Sln(Cre/+) mouse atria, but there were no morphological, physiological, or molecular biological abnormalities. The properties of contractility and Ca(2+) handling were similar to wild-type (WT) mice, and expression levels of several stress markers and sarcoplasmic reticulum-related protein levels were not different between Sln(Cre/+) and WT mice. Moreover, there was no significant difference in sarco(endo)plasmic reticulum Ca(2+)-ATPase activity between the two groups. We showed that Sln(Cre/+) mice were not significantly different from WT mice in all aspects that were examined. The present study provides basic characteristics of Sln(Cre/+) mice and possibly information on the usefulness of Sln(Cre/+) mice as an atrium-specific gene-targeting model. PMID:26519028

  18. Dipyridamole cardiac imaging

    SciTech Connect

    Iskandrian, A.S.; Heo, J.; Askenase, A.; Segal, B.L.; Auerbach, N.

    1988-02-01

    Dipyridamole cardiac imaging is a useful alternative technique to exercise stress testing in the evaluation of patients with ischemic heart disease. Intravenous dipyridamole is still in the investigational phase, while oral dipyridamole is widely available. The hemodynamic effects of dipyridamole include an increase in coronary blood flow (due to coronary vasodilation) which is in excess of the increase in myocardial oxygen consumption and cardiac output. The disparity in the increase in coronary blood flow relative to the cardiac output results in an increase in myocardial thallium activity and an increase in the myocardial/background activity ratio. The quality of the thallium images is better or similar to that of exercise thallium images. The optimal dose of intravenous dipyridamole is 0.56 mg/kg, and of the oral dose it is 300 to 400 mg, although higher doses may be necessary in some patients. Analysis of the thallium images has been to a large extent based on visual inspection of the planar images. Delayed images are helpful to establish the nature of the perfusion abnormalities (transient or fixed). The process of redistribution is based on disparate rates of washout from the normal and abnormal zones. The sensitivity and specificity of dipyridamole thallium imaging, whether intravenous or oral, have been shown in a number of studies to be quite adequate and comparable to that achieved during exercise thallium imaging. Dipyridamole two-dimensional echocardiography has also been used in the detection of coronary artery disease; transient (new or worsening of preexisting) wall motion abnormalities have been found to be a specific marker of coronary artery disease. Transmural as well as regional coronary steal phenomena have been postulated as the mechanism for dipyridamole-induced regional wall motion abnormalities. 65 references.

  19. [Cardiac amyloidosis].

    PubMed

    Hoyer, Caroline; Angermann, Christiane E; Knop, Stefan; Ertl, Georg; Störk, Stefan

    2008-03-15

    Amyloidoses are a heterogeneous group of multisystem disorders, which are characterized by an extracellular deposition of amyloid fibrils. Typically affected are the heart, liver, kidneys, and nervous system. More than half of the patients die due to cardiac involvement. Clinical signs of cardiac amyloidosis are edema of the lower limbs, hepatomegaly, ascites and elevated jugular vein pressure, frequently in combination with dyspnea. There can also be chest pain, probably due to microvessel disease. Dysfunction of the autonomous nervous system or arrhythmias may cause low blood pressure, dizziness, or recurrent syncope. The AL amyloidosis caused by the deposition of immunoglobulin light chains is the most common form. It can be performed by monoclonal gammopathy. The desirable treatment therapy consists of high-dose melphalan therapy twice followed by autologous stem cell transplantation. Due to the high peritransplantation mortality, selection of appropriate patients is mandatory. The ATTR amyloidosis is an autosomal dominant disorder caused by the amyloidogenic form of transthyretin, a plasmaprotein that is synthesized in the liver. Therefore, liver transplantation is the only curative therapy. The symptomatic treatment of cardiac amyloidosis is based on the current guidelines for chronic heart failure according to the patient's New York Heart Association (NYHA) state. Further types of amyloidosis with possible cardiac involvement comprise the senile systemic amyloidosis caused by the wild-type transthyretin, secondary amyloidosis after chronic systemic inflammation, and the beta(2)-microglobulin amyloidosis after long-term dialysis treatment. PMID:18344065

  20. [Multiple cardiac rhabdomyoma associated to intrauterine death].

    PubMed

    Morales-Quispe, Jorge A; Espínola-Zavaleta, Nilda; Caballero-Caballero, Rocío; Brunner-Cruz, Guadalupe; Uribe Alcántara, Sergio

    2011-01-01

    Rhabdomyoma is the most common cardiac tumor detected during fetal life and childhood; nevertheless its incidence is very low. This is a histologically benign tumor, but in some cases may cause hemodynamic repercussion with date of low cardiac output, arrhythmias and exceptionally intrauterine death as occurred in our case, which was detected by obstetric ultrasound and fetal echocardiogram and corroborated by histological study. PMID:21975236

  1. Myocardial Dysfunction and Shock after Cardiac Arrest

    PubMed Central

    Jentzer, Jacob C.; Chonde, Meshe D.; Dezfulian, Cameron

    2015-01-01

    Postarrest myocardial dysfunction includes the development of low cardiac output or ventricular systolic or diastolic dysfunction after cardiac arrest. Impaired left ventricular systolic function is reported in nearly two-thirds of patients resuscitated after cardiac arrest. Hypotension and shock requiring vasopressor support are similarly common after cardiac arrest. Whereas shock requiring vasopressor support is consistently associated with an adverse outcome after cardiac arrest, the association between myocardial dysfunction and outcomes is less clear. Myocardial dysfunction and shock after cardiac arrest develop as the result of preexisting cardiac pathology with multiple superimposed insults from resuscitation. The pathophysiology involves cardiovascular ischemia/reperfusion injury and cardiovascular toxicity from excessive levels of inflammatory cytokine activation and catecholamines, among other contributing factors. Similar mechanisms occur in myocardial dysfunction after cardiopulmonary bypass, in sepsis, and in stress-induced cardiomyopathy. Hemodynamic stabilization after resuscitation from cardiac arrest involves restoration of preload, vasopressors to support arterial pressure, and inotropic support if needed to reverse the effects of myocardial dysfunction and improve systemic perfusion. Further research is needed to define the role of postarrest myocardial dysfunction on cardiac arrest outcomes and identify therapeutic strategies. PMID:26421284

  2. Biomechanics of Cardiac Function.

    PubMed

    Voorhees, Andrew P; Han, Hai-Chao

    2015-10-01

    The heart pumps blood to maintain circulation and ensure the delivery of oxygenated blood to all the organs of the body. Mechanics play a critical role in governing and regulating heart function under both normal and pathological conditions. Biological processes and mechanical stress are coupled together in regulating myocyte function and extracellular matrix structure thus controlling heart function. Here, we offer a brief introduction to the biomechanics of left ventricular function and then summarize recent progress in the study of the effects of mechanical stress on ventricular wall remodeling and cardiac function as well as the effects of wall mechanical properties on cardiac function in normal and dysfunctional hearts. Various mechanical models to determine wall stress and cardiac function in normal and diseased hearts with both systolic and diastolic dysfunction are discussed. The results of these studies have enhanced our understanding of the biomechanical mechanism in the development and remodeling of normal and dysfunctional hearts. Biomechanics provide a tool to understand the mechanism of left ventricular remodeling in diastolic and systolic dysfunction and guidance in designing and developing new treatments. PMID:26426462

  3. Robotic cardiac surgery: an anaesthetic challenge.

    PubMed

    Wang, Gang; Gao, Changqing

    2014-08-01

    Robotic cardiac surgery with the da Vinci robotic surgical system offers the benefits of a minimally invasive procedure, including a smaller incision and scar, reduced risk of infection, less pain and trauma, less bleeding and blood transfusion requirements, shorter hospital stay and decreased recovery time. Robotic cardiac surgery includes extracardiac and intracardiac procedures. Extracardiac procedures are often performed on a beating heart. Intracardiac procedures require the aid of peripheral cardiopulmonary bypass via a minithoracotomy. Robotic cardiac surgery, however, poses challenges to the anaesthetist, as the obligatory one-lung ventilation (OLV) and CO2 insufflation may reduce cardiac output and increase pulmonary vascular resistance, potentially resulting in hypoxaemia and haemodynamic compromise. In addition, surgery requires appropriate positioning of specialised cannulae such as an endopulmonary vent, endocoronary sinus catheter, and endoaortic clamp catheter under the guidance of transoesophageal echocardiography. Therefore, cardiac anaesthetists should have a working knowledge of these systems, OLV and haemodynamic support. PMID:24958894

  4. Simultaneous separate assessment of the cardiac and LVAD output.

    PubMed

    Chaus, N I; Kislukhin, V V; Smirnov, S S; Ivanov, A S; Zhidkov, I L; Burtsev PYu; Eremenko, A A; Dzemeshkevich, S L; Pentalos, G M; Kolff, W J

    1997-07-01

    The electroimpedance indicators' dilution (EIID) technique was used to study the possibility of a simultaneous separate assessment of the biological heart and LVAD performance in the position of LVB. The experimental part of the research was performed on 5 dogs; an artificial ventricle of the pulsing type (USA) with cusps was used as a pump. The clinical part of the work was conducted on 5 patients after open-heart surgery who had the clinical picture of postcardiotomy cardiogenic shock; a centrifugal pump "Biopump" (Medtronic, USA) was used. The authors have shown a principally important possibility of applying the EIID, technique for studying the performance curves which are the integral derivatives of the work of a specific hybrid system--"the biological heart-assist device". From the practical viewpoint the EIID technique permits in the read time mode to control continuously the part of the pumping function which is assumed by the patient's own heart. This information can serve as the basis for making the prognosis and determining the further tactics of treatment; the restoration of the heart performance or its replacement by transplantation. PMID:9298411

  5. Maintaining Medicinal Plant Germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For all plant genetic resources collections, including medicinal plant germplasm, maintaining the genetic integrity of material held ex situ is of major importance. This holds true for all intended end uses of the material whether it is as a source for crop improvement, medical research, as voucher...

  6. Cardiac optogenetics

    PubMed Central

    2013-01-01

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

  7. Cardiac Surgery

    PubMed Central

    Weisse, Allen B.

    2011-01-01

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

  8. Nuclear power plant maintainability.

    PubMed

    Seminara, J L; Parsons, S O

    1982-09-01

    In the mid-1970s a general awareness of human factors engineering deficiencies associated with power plant control rooms took shape and the Electric Power Research Institute (EPRI) awarded the Lockheed Corporation a contract to review the human factors aspects of five representative operational control rooms and their associated simulators. This investigation revealed a host of major and minor deficiencies that assumed unforeseen dimensions in the post- Three Mile Island accident period. In the course of examining operational problems (Seminara et al, 1976) and subsequently the methods for overcoming such problems (Seminara et al, 1979, 1980) indications surfaced that power plants were far from ideal in meeting the needs of maintenance personnel. Accordingly, EPRI sponsored an investigation of the human factors aspects of power plant maintainability (Seminara, 1981). This paper provides an overview of the maintainability problems and issues encountered in the course of reviewing five nuclear power plants. PMID:15676441

  9. Acoustic Levitator Maintains Resonance

    NASA Technical Reports Server (NTRS)

    Barmatz, M. B.; Gaspar, M. S.

    1986-01-01

    Transducer loading characteristics allow resonance tracked at high temperature. Acoustic-levitation chamber length automatically adjusted to maintain resonance at constant acoustic frequency as temperature changes. Developed for containerless processing of materials at high temperatures, system does not rely on microphones as resonance sensors, since microphones are difficult to fabricate for use at temperatures above 500 degrees C. Instead, system uses acoustic transducer itself as sensor.

  10. Obtaining and maintaining funding

    SciTech Connect

    Beverly Hartline

    1996-04-01

    Obtaining and maintaining funding is important for individuals, groups, institutions, and fields. This challenge is easier during times of abundant and growing resources than it is now, when funding is tight and shrinking. Thus, to obtain and maintain funding will require: maintaining healthy funding levels for all of science; maintaining healthy funding levels for the field(s) you work in; and competing successfully for the available funds. Everyone should pay attention to the overall prospects for science funding and dedicate some effort to working with others to grow the constituency for science. Public support is likely an important prerequisite for keeping future science budgets high. In this context, researchers should share with society at large the benefits of their research, so that taxpayers can see and appreciate some return from the federal investment in science. Assuming this effort is successful, and there continue to be government and private organizations with substantial resources to invest in research, what can the individual investigator do to improve her chances? She can be clear about her goal(s) and carefully plan her effort to make maximum progress for minimum resources, especially early in her career while she is establishing a solid professional reputation. Specific useful strategies include: brainstorm funding options and select the most promising one(s); be persistent but flexible, responsive to new information and changing circumstances; provide value and assistance to prospective funding sources both before and after receiving funding; know the funding agents and what their goals are, they are the customers; promise a lot and always deliver more; build partnerships and collaboration to leverage interest and resources; and develop capabilities and ideas with a promising, irresistible future. There is no guarantee of success. For the best chances, consistently contribute positively and productively in all your efforts, and continue to work for healthy funding levels for your field, your institution, and all of science.

  11. Diodes stabilize LED output

    NASA Technical Reports Server (NTRS)

    Deters, R. A.

    1977-01-01

    Small-signal diodes are placed in series with light-emitting diodes (LED's) to stabilize LED output against temperature fluctuations. Simple inexpensive method compensates for thermal fluctuations over a broad temperature range. Requiring few components, technique is particularly useful where circuit-board space is limited.

  12. Aging Impairs Myocardial Fatty Acid and Ketone Oxidation and Modifies Cardiac Functional and Metabolic Responses to Insulin in Mice

    SciTech Connect

    Hyyti, Outi M.; Ledee, Dolena; Ning, Xue-Han; Ge, Ming; Portman, Michael A.

    2010-07-02

    Aging presumably initiates shifts in substrate oxidation mediated in part by changes in insulin sensitivity. Similar shifts occur with cardiac hypertrophy and may contribute to contractile dysfunction. We tested the hypothesis that aging modifies substrate utilization and alters insulin sensitivity in mouse heart when provided multiple substrates. In vivo cardiac function was measured with microtipped pressure transducers in the left ventricle from control (4–6 mo) and aged (22–24 mo) mice. Cardiac function was also measured in isolated working hearts along with substrate and anaplerotic fractional contributions to the citric acid cycle (CAC) by using perfusate containing 13C-labeled free fatty acids (FFA), acetoacetate, lactate, and unlabeled glucose. Stroke volume and cardiac output were diminished in aged mice in vivo, but pressure development was preserved. Systolic and diastolic functions were maintained in aged isolated hearts. Insulin prompted an increase in systolic function in aged hearts, resulting in an increase in cardiac efficiency. FFA and ketone flux were present but were markedly impaired in aged hearts. These changes in myocardial substrate utilization corresponded to alterations in circulating lipids, thyroid hormone, and reductions in protein expression for peroxisome proliferator-activated receptor (PPAR)α and pyruvate dehydrogenase kinase (PDK)4. Insulin further suppressed FFA oxidation in the aged. Insulin stimulation of anaplerosis in control hearts was absent in the aged. The aged heart shows metabolic plasticity by accessing multiple substrates to maintain function. However, fatty acid oxidation capacity is limited. Impaired insulin-stimulated anaplerosis may contribute to elevated cardiac efficiency, but may also limit response to acute stress through depletion of CAC intermediates.

  13. Cardiac arrest equipment to support circulation.

    PubMed

    Aldridge, Matthew; Jevon, Phil

    Cardiac arrest trolleys must be equipped with all the instruments and medication needed to deal with an acute adult cardiac arrest. Nurses must not only be familiar with these contents but also know how to use, check and maintain them. This first part of this two-part series looked at equipment to aid airway and breathing; this second part focuses on circulation. Note that drug doses mentioned here relate to the adult patient and will be different for children. PMID:25223000

  14. Seamless service: maintaining momentum.

    PubMed

    Grinstead, N; Timoney, R

    1994-01-01

    Describes the process used by the Mater Infirmorum Hospital in Belfast in 1992-1994 to achieve high quality care (Seamless Service), motivate staff to deliver and measure performance. Aims of the project include focusing the organization on the customer, improving teamwork and motivation at all levels. After comprehensive data collection from GPs, patients and staff management forums developed a full TQM strategy to gain support and maintain momentum including innovative staff events (every staff member was given the opportunity to attend) where multilevel, multidisciplinary workshops enabled staff to design customer care standards, develop teams and lead customer-driven change. PMID:10137901

  15. Increase in cardiac myosin heavy-chain (MyHC) alpha protein isoform in hibernating ground squirrels, with echocardiographic visualization of ventricular wall hypertrophy and prolonged contraction

    PubMed Central

    Nelson, O. Lynne; Rourke, Bryan C.

    2013-01-01

    SUMMARY Deep hibernators such as golden-mantled ground squirrels (Callospermophilus lateralis) have multiple challenges to cardiac function during low temperature torpor and subsequent arousals. As heart rates fall from over 300 beats min−1 to less than 10, chamber dilation and reduced cardiac output could lead to congestive myopathy. We performed echocardiography on a cohort of individuals prior to and after several months of hibernation. The left ventricular chamber exhibited eccentric and concentric hypertrophy during hibernation and thus calculated ventricular mass was ~30% greater. Ventricular ejection fraction was mildly reduced during hibernation but stroke volumes were greater due to the eccentric hypertrophy and dramatically increased diastolic filling volumes. Globally, the systolic phase in hibernation was ~9.5 times longer, and the diastolic phase was 28× longer. Left atrial ejection generally was not observed during hibernation. Atrial ejection returned weakly during early arousal. Strain echocardiography assessed the velocity and total movement distance of contraction and relaxation for regional ventricular segments in active and early arousal states. Myocardial systolic strain during early arousal was significantly greater than the active state, indicating greater total contractile movement. This mirrored the increased ventricular ejection fraction noted with early arousal. However, strain rates were slower during early arousal than during the active period, particularly systolic strain, which was 33% of active, compared with the rate of diastolic strain, which was 67% of active. As heart rate rose during the arousal period, myocardial velocities and strain rates also increased; this was matched closely by cardiac output. Curiously, though heart rates were only 26% of active heart rates during early arousal, the cardiac output was nearly 40% of the active state, suggesting an efficient pumping system. We further analyzed proportions of cardiac myosin heavy-chain (MyHC) isoforms in a separate cohort of squirrels over 5 months, including time points before hibernation, during hibernation and just prior to emergence. Hibernating individuals were maintained in both a 4°C cold room and a 20°C warm room. Measured by SDS-PAGE, relative percentages of cardiac MyHC alpha were increased during hibernation, at both hibernacula temperatures. A potential increase in contractile speed, and power, from more abundant MyHC alpha may aid force generation at low temperature and at low heart rates. Unlike many models of cardiomyopathies where the alpha isoform is replaced by the beta isoform in order to reduce oxygen consumption, ground squirrels demonstrate a potential cardioprotective mechanism to maintain cardiac output during torpor. PMID:24072796

  16. [Maintaining telomere length].

    PubMed

    Wysoczańska, Barbara

    2013-01-01

    Telomeres protect the ends of chromosomes maintaining genome stability. The activity of telomerase enzyme, or alternatively the process of recombination, regulates the length of telomeres. In the absence of these mechanisms, excessive shortening of telomeres reach its critical level. Excessively shortened telomeres do not protect chromosome ends, the cell division cycle is stopped while the inactivity of replication process generates cellular senescence and cell death. On the other hand, critically shortened telomeres may promote chromosomal instability. These changes can lead to the development of carcinogenesis. In this process enzymatic activity of telomerase is reactivated. To maintain the protection of the chromosome ends, telomeres bind the stabilizing protein complex (shelterin). The presence of these protective proteins prevents undesirable DNA damage and initiates the repair system pathways. Molecular technologies enable the evaluation of telomere lengths, the analysis of telomerase expression and activity, and detection of mutations, polymorphic and epigenetic changes in telomere--shelterin--telomerase complex related genes. The purpose of research is to describe new mechanisms that affect the biology of telomere lengths, and to determine the impact on bone marrow failures, development of haematological malignancies, neurodegenerative diseases and others disorders associated with chromosomal instability. The model of modern therapies based on telomere biology explains the significance of the maintenance of telomere lengths in the process of cellular senescence and carcinogenesis. PMID:24379272

  17. Does PKMζ maintain memory?

    PubMed Central

    Kwapis, Janine L.; Helmstetter, Fred J.

    2013-01-01

    Work on the long-term stability of memory has identified a potentially critical role for protein kinase Mzeta (PKMζ) in maintaining established memory. PKMζ, an autonomously active isoform of PKC, is hypothesized to sustain those changes that occurred during memory formation in order to preserve the memory engram over time. Initial studies investigating the role of PKMζ were largely successful in demonstrating a role for the kinase in memory maintenance; disrupting PKMζ activity with ζ-inhibitory peptide (ZIP) was successful in disrupting a variety of established associations in a number of key brain regions. More recent work, however, has questioned both the role of PKMζ in memory maintenance and the effectiveness of ZIP as a specific inhibitor of PKMζ activity. Here, we outline the research both for and against the idea that PKMζ is a memory maintenance mechanism and discuss how these two lines of research can be reconciled. We conclude by proposing a number of studies that would help to clarify the role of PKMζ in memory and define other mechanisms the brain may use to maintain memory. PMID:24076105

  18. Climate Model Output Rewriter

    Energy Science and Technology Software Center (ESTSC)

    2004-06-21

    CMOR comprises a set of FORTRAN 90 dunctions that can be used to produce CF-compliant netCDF files. The structure of the files created by CMOR and the metadata they contain fulfill the requirements of many of the climate community’s standard model experiments (which are referred to here as "MIPS", which stands for "model intercomparison project", including, for example, AMIP, CMIP, CFMIP, PMIP, APE, and IPCC scenario runs), CMOR was not designed to serve as anmore » all-purpose wfiter of CF-compliant netCDF files, but simply to reduce the effort required to prepare and manage MIP data. Although MIPs encourage systematic analysis of results across models, this is only easy to do if the model output is written in a common format with files structured similarly and with sufficient metadata uniformly stored according to a common standard. Individual modeling groups store their data in different ways. but if a group can read its own data with FORTRAN, then it should easily be able to transform the data, using CMOR, into the common format required by the MIPs, The adoption of CMOR as a standard code for exchanging climate data will facilitate participation in MIPs because after learning how to satisfy the output requirements of one MIP, it will be easy to prepare output for the other MIPs.« less

  19. Reagan: Maintain Antarctic program

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    President Ronald Reagan has decided that the United States should maintain an ‘active and influential presence’ in Antarctica to support the nation's interests. Following a review of a study by the Antarctica Policy Group, Reagan issued a memorandum, dated February 5, to the heads of 14 government agencies, including the National Science Foundation (NSF), the Office of Science and Technology Policy, and the Office of Management and Budget.The U.S. presence in Antarctica ‘shall include the conduct of scientific activities in major disciplines; year-round occupation of the South Pole and two coastal stations; and availability of related necessary logistics support,’ wrote the President. In addition, NSF should continue to budget for the entire U.S. program in Antarctica. Short-term programs by other agencies require the recommendation of the Antarctica Policy Group and should be coordinated within the framework of NSF logistics support.

  20. [Cardiac surgery in the aged].

    PubMed

    Asano, K

    1988-01-01

    One hundred and seven patients aged greater than or equal to 60 years with cardiac surgery were reviewed. These patients underwent open heart surgery at University Hospital of Tokyo and JR Tokyo General Hospital during 1981 to 1987. Prevalence of the elderly with 60 years or older in all patients with cardiac surgery increased 4.1% to 20% during these seven years. Surgery for ischemic heart disease has become more common. There were less number of cases with valvular heart disease referred for surgery, but, not a few cases with calcified aortic valve or floppy mitral valve had valve replacement. Operative results were as follows: Hospital death was 6/107 patients (5.6%) and three patients died after discharge. This group of old patients was occasionally associated (14/107, 13%) with a variety of diseases including bronchial asthma, diabetes mellitus, and other atherosclerotic lesion or liver dysfunction. Valvular heart disease was not rarely complicated with ischemic heart disease. Postoperative complications were mainly due to renal failure, respiratory failure or low output syndrome, possibly related to associated disease. Intra-aortic balloon pumping was performed in seven of 107 patients, four of whom eventually died. In conclusion, there is a relatively high risk in cardiac surgery in old aged patients with associated diseases. We have to manage carefully old patients to avoid major postoperative complications including cardiac, respiratory and renal events. Much more old patients will have open heart surgery in the future. PMID:3274213

  1. Is levosimendan effective in paediatric heart failure and post-cardiac surgeries?

    PubMed

    Angadi, Ullas; Westrope, Claire; Chowdhry, Mohammed F

    2013-10-01

    A best evidence topic in cardiothoracic surgery was written according to a structured protocol. The question addressed was 'do children with heart failure post-cardiac surgery undergoing treatment with levosimendan have an acceptable haemodynamic improvement?' The use of levosimendan as a vasoactive drug is an accepted intervention for patients with altered haemodynamics post-cardiac surgeries. However, the role of levosimendan and its efficacy have been debated. Eleven relevant papers were identified, which represented the best evidence to answer the question. The author, journal, date, country of publication and relevant outcomes are tabulated. The 11 studies comprised 3 randomized trials, 2 of which compared levosimendan and milrinone. A single-centre randomized study that included 40 infants showed that cardiac output (CO) and cardiac index (CI) increased overtime in the levosimendan group compared with the milrinone group. The significant interaction for CO (P = 0.005) and CI (P = 0.007) indicated different time courses in the two groups. A similar, European randomized study undertaken on neonates (n = 63) showed better lactate levels [P = 0.015 (intensive care admission); P = 0.048 (after 6 h) with low inotropic scores in the levosimendan group. Although the length of mechanical ventilation and mortality were less, this was statistically insignificant. A retrospective cohort analysis (n = 13) in children reported a reduced use of dobutamine and improvement in the ejection fraction from 29.8 to 40.5% (P = 0.015) with the use of levosimendan. In a questionnaire-based study from Finland, 61.1% of respondents felt that it had saved the lives of some children when the other treatments had failed. No study reported any adverse effect attributable to use of levosimendan. In conclusion, the above studies were in favour of levosimendan as a safe and feasible drug providing potential clinical benefit in low cardiac output syndrome (LCOS) and post-cardiac surgeries when other vasoactive drugs were insufficient to maintain stable haemodynamics. A small sample size was indeed a limitation in all the above studies. Furthermore, it is best used as a rescue drug on a named-patient basis. A small sample size was indeed a limitation in all the above studies. Larger, well-designed trials are required to further evaluate the efficacy and feasibility of levosimendan in paediatric heart failure and post-cardiac surgeries. PMID:23832921

  2. Different Contribution of Splanchnic Organs to Hyperlactatemia in Fecal Peritonitis and Cardiac Tamponade

    PubMed Central

    Gorrasi, José; Eleftheriadis, Anestis; Takala, Jukka; Brandt, Sebastian; Djafarzadeh, Siamak; Bruegger, Lukas E.; Bracht, Hendrik; Jakob, Stephan M.

    2013-01-01

    Background. Changes in hepatosplanchnic lactate exchange are likely to contribute to hyperlactatemia in sepsis. We hypothesized that septic and cardiogenic shock have different effects on hepatosplanchnic lactate exchange and its contribution to hyperlactatemia. Materials and Methods. 24 anesthetized pigs were randomized to fecal peritonitis (P), cardiac tamponade (CT), and to controls (n = 8 per group). Oxygen transport and lactate exchange were calculated during 24 hours. Results. While hepatic lactate influx increased in P and in CT, hepatic lactate uptake remained unchanged in P and decreased in CT. Hepatic lactate efflux contributed 20% (P) and 33% (CT), respectively, to whole body venous efflux. Despite maintained hepatic arterial blood flow, hepatic oxygen extraction did not increase in CT. Conclusions. Whole body venous lactate efflux is of similar magnitude in hyperdynamic sepsis and in cardiogenic shock. Although jejunal mucosal pCO2 gradients are increased, enhanced lactate production from other tissues is more relevant to the increased arterial lactate. Nevertheless, the liver fails to increase hepatic lactate extraction in response to rising hepatic lactate influx, despite maintained hepatic oxygen consumption. In cardiac tamponade, regional, extrasplanchnic lactate production is accompanied by hepatic failure to increase oxygen extraction and net hepatic lactate output, despite maintained hepatic arterial perfusion. PMID:24228242

  3. Modes of induced cardiac arrest: hyperkalemia and hypocalcemia - Literature review

    PubMed Central

    de Oliveira, Marcos Aurélio Barboza; Brandi, Antônio Carlos; dos Santos, Carlos Alberto; Botelho, Paulo Henrique Husseini; Cortez, José Luis Lasso; Braile, Domingo Marcolino

    2014-01-01

    The entry of sodium and calcium play a key effect on myocyte subjected to cardiac arrest by hyperkalemia. They cause cell swelling, acidosis, consumption of adenosine triphosphate and trigger programmed cell death. Cardiac arrest caused by hypocalcemia maintains intracellular adenosine triphosphate levels, improves diastolic performance and reduces oxygen consumption, which can be translated into better protection to myocyte injury induced by cardiac arrest. PMID:25372919

  4. Maintaining proper dental records.

    PubMed

    Leeuw, Wilhemina

    2014-01-01

    Referred to as Standard of Care, the legal duty of a dentist requires exercising the degree of skill and care that would be exhibited by other prudent dentists faced with the same patient-care situation. Primarily, the goal of keeping good dental records is to maintain continuity of care. Diligent and complete documentation and charting procedures are essential to fulfilling the Standard of Care. Secondly, because dental records are considered legal documents they help protect the interest of the dentist and/or the patient by establishing the details of the services rendered. Patients today are better educated and more assertive than ever before and dentists must be equipped to protect themselves against malpractice claims. Every record component must be handled as if it could be summoned to a court room and scrutinized by an attorney, judge or jury. Complete, accurate, objective and honest entries in a patient record are the only way to defend against any clinical and/or legal problems that might arise. Most medical and dental malpractice claims arise from an unfavorable interaction with the dentist and not from a poor treatment outcome. By implementing the suggestions mentioned in this course, dental health care professionals can minimize the legal risks associated with the delivery of dental care to promote greater understanding for patients of their rights and privileges to their complete record. PMID:24834675

  5. Cardiac Cells Beating in Culture: A Laboratory Exercise

    ERIC Educational Resources Information Center

    Weaver, Debora

    2007-01-01

    This article describes how to establish a primary tissue culture, where cells are taken directly from an organ of a living animal. Cardiac cells are taken from chick embryos and transferred to culture dishes. These cells are not transformed and therefore have a limited life span. However, the unique characteristics of cardiac cells are maintained

  6. ADAS Update and Maintainability

    NASA Technical Reports Server (NTRS)

    Watson, Leela R.

    2010-01-01

    Since 2000, both the National Weather Service Melbourne (NWS MLB) and the Spaceflight Meteorology Group (SMG) have used a local data integration system (LOIS) as part of their forecast and warning operations. The original LOIS was developed by the Applied Meteorology Unit (AMU) in 1998 (Manobianco and Case 1998) and has undergone subsequent improvements. Each has benefited from three-dimensional (3-D) analyses that are delivered to forecasters every 15 minutes across the peninsula of Florida. The intent is to generate products that enhance short-range weather forecasts issued in support of NWS MLB and SMG operational requirements within East Central Florida. The current LDIS uses the Advanced Regional Prediction System (ARPS) Data Analysis System (AD AS) package as its core, which integrates a wide variety of national, regional, and local observational data sets. It assimilates all available real-time data within its domain and is run at a finer spatial and temporal resolution than current national or regional-scale analysis packages. As such, it provides local forecasters with a more comprehensive understanding of evolving fine-scale weather features. Over the years, the LDIS has become problematic to maintain since it depends on AMU-developed shell scripts that were written for an earlier version of the ADAS software. The goals of this task were to update the NWS MLB/SMG LDIS with the latest version of ADAS, incorporate new sources of observational data, and upgrade and modify the AMU-developed shell scripts written to govern the system. In addition, the previously developed ADAS graphical user interface (GUI) was updated. Operationally, these upgrades will result in more accurate depictions of the current local environment to help with short-range weather forecasting applications, while also offering an improved initialization for local versions of the Weather Research and Forecasting (WRF) model used by both groups.

  7. Comparison of the cardiac pumping capability and cardiac pumping reserve in double-muscled and conventional calves.

    PubMed

    Amory, H; McEntee, K; Linden, A S; Desmecht, D J; Beduin, J M; D'Orio, V; Lekeux, P M

    1993-12-01

    Hereditary muscular hypertrophy is a character that has been selected in several animal species for industrial meat production. The selection of this character in cattle produces animals of exceptional commercial value but ones with a lower aerobic capacity than that of conventional cattle. The purpose of this work was to study the role of cardiac function as a potential limiting factor of aerobic capacity in double-muscled calves. Two groups of healthy calves were studied, one consisting of nine calves of conventional conformation and the other of nine double-muscled calves. Pulmonary arterial and capillary wedge, central venous, and systemic arterial pressures were measured by fluid-filled catheters and recorded together with the electrocardiogram. Cardiac output was measured by the thermodilution technique. From these measurements, the heart rate, the cardiac and the stroke indices, the pulmonary and the systemic vascular resistances, and the cardiac power output were calculated. The parameters were recorded under basal resting conditions and during incremental dobutamine challenge, which allowed determination of the resting cardiac power output, the cardiac pumping capability, and the cardiac reserve. Dobutamine challenge induced a significant rise in cardiac and stroke indices, heart rate, and cardiac power output, a significant decrease in pulmonary and systemic vascular resistances, and no change in systemic and pulmonary arterial pressures. The cardiac reserve obtained in the present study was low in comparison with those previously reported in humans, dogs, and horses. This may be related to the poor running capability of bovine species relative to that of the former species.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8180890

  8. Loss of Rad-GTPase produces a novel adaptive cardiac phenotype resistant to systolic decline with aging.

    PubMed

    Manning, Janet R; Withers, Catherine N; Levitan, Bryana; Smith, Jeffrey D; Andres, Douglas A; Satin, Jonathan

    2015-10-01

    Rad-GTPase is a regulator of L-type calcium current (LTCC), with increased calcium current observed in Rad knockout models. While mouse models that result in elevated LTCC have been associated with heart failure, our laboratory and others observe a hypercontractile phenotype with enhanced calcium homeostasis in Rad(-/-). It is currently unclear whether this observation represents an early time point in a decompensatory progression towards heart failure or whether Rad loss drives a novel phenotype with stable enhanced function. We test the hypothesis that Rad(-/-) drives a stable nonfailing hypercontractile phenotype in adult hearts, and we examine compensatory regulation of sarcoplasmic reticulum (SR) loading and protein changes. Heart function was measured in vivo with echocardiography. In vivo heart function was significantly improved in adult Rad(-/-) hearts compared with wild type. Heart wall dimensions were significantly increased, while heart size was decreased, and cardiac output was not changed. Cardiac function was maintained through 18 mo of age with no decompensation. SR releasable Ca(2+) was increased in isolated Rad(-/-) ventricular myocytes. Higher Ca(2+) load was accompanied by sarco/endoplasmic reticulum Ca(2+) ATPase 2a (SERCA2a) protein elevation as determined by immunoblotting and a rightward shift in the thapsigargan inhibitor-response curve. Rad(-/-) promotes morphological changes accompanied by a stable increase in contractility with aging and preserved cardiac output. The Rad(-/-) phenotype is marked by enhanced systolic and diastolic function with increased SR uptake, which is consistent with a model that does not progress into heart failure. PMID:26371164

  9. Cardiac performance in relation to oxygen supply varies with dietary lipid composition in sturgeon.

    PubMed

    Agnisola, C; McKenzie, D J; Taylor, E W; Bolis, C L; Tota, B

    1996-08-01

    Dietary polyunsaturated fatty acids (PUFA) of the n-3 series that have beneficial effects on mammalian heart function are typically found at high levels in fish tissues. The effects of dietary fatty acid composition on cardiac function were investigated in the sturgeon. When compared with sturgeon maintained for 1 yr on a diet enriched with saturated fatty acids (SFA) (the coconut oil-supplemented diet, COD), sturgeon maintained on a diet enriched with n-3 PUFA (the fish oil-supplemented diet, FOD) had higher myocardial 20:5(n-3) and lower 20:4(n-6) content with a consequent decrease in the n-6-to-n-3 ratio (from 0.86 to 0.25) and a lower intrinsic in vitro heart rate (22.0 +/- 1.5 vs. 29.9 +/- 1.0 beats/min) and cardiac power output (PO) (0.33 +/- 0.08 vs. 0.48 +/- 0.03 mW/g), but had a greater in vitro scope for cardiac work (almost twice the maximal-to-basal PO ratio). Reducing the oxygen supply to the hearts significantly decreased, by approximately 40%, the maximal in vitro PO in the COD group of animals but had no effect in the FOD group. These differences in performance were not reflected in heart rate or blood pressure in vivo, either in normoxia or hypoxia. Addition of vitamin E as an antioxidant to the diets reduced intrinsic heart rate by approximately 25% but did not influence the effects (dietary fatty acid composition on in vitro cardiac performance. The results indicate that dietary n-3 PUFA can have beneficial effects on the resistance of the fish heart to environmental stressors such as hypoxia. PMID:8770143

  10. Cardiac regeneration therapy: connections to cardiac physiology.

    PubMed

    Takehara, Naofumi; Matsubara, Hiroaki

    2011-12-01

    Without heart transplantation, a large number of patients with failing hearts worldwide face poor outcomes. By means of cardiomyocyte regeneration, cardiac regeneration therapy is emerging with great promise as a means for restoring loss of cardiac function. However, the limited success of clinical trials using bone marrow-derived cells and myoblasts with heterogeneous constituents, transplanted at a wide range of cell doses, has led to disagreement on the efficacy of cell therapy. It is therefore essential to reevaluate the evidence for the efficacy of cell-based cardiac regeneration therapy, focusing on targets, materials, and methodologies. Meanwhile, the revolutionary innovation of cardiac regeneration therapy is sorely needed to help the millions of people who suffer heart failure from acquired loss of cardiomyocytes. Cardiac regeneration has been used only in limited species or as a developing process in the rodent heart; now, the possibility of cardiomyocyte turnover in the human heart is being revisited. In the pursuit of this concept, the use of cardiac stem/progenitor stem cells in the cardiac niche must be focused to usher in a second era of cardiac regeneration therapy for the severely injured heart. In addition, tissue engineering and cellular reprogramming will advance the next era of treatment that will enable current cell-based therapy to progress to "real" cardiac regeneration therapy. Although many barriers remain, the prevention of refractory heart failure through cardiac regeneration is now becoming a realistic possibility. PMID:21963835

  11. Cardiac matrix: a clue for future therapy

    PubMed Central

    Mishra, Paras Kumar; Givvimani, Srikanth; Chavali, Vishalakshi; Tyagi, Suresh C.

    2014-01-01

    Cardiac muscle is unique because it contracts ceaselessly throughout the life and is highly resistant to fatigue. The marvelous nature of the cardiac muscle is attributed to its matrix that maintains structural and functional integrity and provides ambient micro-environment required for mechanical, cellular and molecular activities in the heart. Cardiac matrix dictates the endothelium-myocyte (E-M) coupling and contractility of cardiomyocytes. The Matrix metalloproteinases (MMPs) and their tissue inhibitor of metalloproteinases (TIMPs) regulate matrix degradation that determines cardiac fibrosis and myocardial performance. We have shown that MMP-9 regulates differential expression of micro RNAs (miRNAs), calcium cycling and contractility of cardiomyocytes. The differential expression of miRNAs is associated with angiogenesis, hypertrophy and fibrosis in the heart. MMP-9, which is involved in the degradation of cardiac matrix and induction of fibrosis, is also implicated in inhibition of survival and differentiation of cardiac stem cells (CSC). Cardiac matrix is distinct because it renders mechanical properties and provides a framework essential for differentiation of cardiac progenitor cells (CPC) into specific lineage. Cardiac matrix regulates myocyte contractility by E-M coupling and calcium transients and also directs miRNAs required for precise regulation of continuous and synchronized beating of cardiomyocytes that is indispensible for survival. Alteration in the matrix homeostasis due to induction of MMPs, altered expression of specific miRNAs or impaired signaling for contractility of cardiomyocytes leads to catastrophic effects. This review describes the mechanisms by which cardiac matrix regulates myocardial performance and suggests future directions for the development of treatment strategies in cardiovascular diseases. PMID:24055000

  12. Cardiac output and cardiac contractility by impedance cardiography during exercise of runners

    NASA Technical Reports Server (NTRS)

    Kubicek, W. G.; Tracy, R. A.

    1994-01-01

    Most of the solid state electronic engineering of the system now generally known as the Minnesota Impedance Cardiograph was performed with the support of a five-year contract, NAS9-4500, with the NASA Lyndon B. Johnson Space Center, Houston, Texas. This contract ran from 1965 to 1970. In addition to the engineering design and development of the hardware, the contract called for testing on both animals and human subjects. This project also provided funds to construct twenty impedance cardiographs and place them in selected research and clinical facilities for further evaluation. This, then, led to the First Symposium on Impedance Cardiography, held at the NASA Lyndon B. Johnson Space Center, Houston, Texas, 2-4 June 1969. Twenty-four excellent papers were presented.

  13. Noninvasive measurement of cardiac performance in recovery from exercise in heart failure patients

    PubMed Central

    Myers, Jonathan N; Gujja, Pradeep; Neelagaru, Suresh; Hsu, Leon; Burkhoff, Daniel

    2011-01-01

    OBJECTIVE: To examine the association between cardiac performance during recovery and the severity of heart failure, as determined by clinical and cardiopulmonary exercise test responses. METHODS: As part of a retrospective cohort study, 46 heart failure patients and 13 normal subjects underwent cardiopulmonary exercise testing while cardiac output was measured using a noninvasive device. Cardiac output in recovery was expressed as the slope of a single exponential relationship between cardiac output and time; the recovery-time constant was assessed in relation to indices of cardiac function, along with clinical, functional, and cardiopulmonary exercise responses. RESULTS: The recovery time constant was delayed in patients with heart failure compared with normal subjects (296.7±238 vs. 110.1±27 seconds, p <0.01), and the slope of the decline of cardiac output in recovery was steeper in normal subjects compared with heart failure patients (p<0.001). The slope of the decline in cardiac output recovery was inversely related to peak VO2 (r = -0.72, p<0.001) and directly related to the VE/VCO2 slope (r = 0.57, p<0.001). Heart failure patients with abnormal recovery time constants had lower peak VO2, lower VO2 at the ventilatory threshold, lower peak cardiac output, and a heightened VE/VCO2 slope during exercise. CONCLUSIONS: Impaired cardiac output recovery kinetics can identify heart failure patients with more severe disease, lower exercise capacity, and inefficient ventilation. Estimating cardiac output in recovery from exercise may provide added insight into the cardiovascular status of patients with heart failure. PMID:21655761

  14. Cardiac surgery in the parturient.

    PubMed

    Chandrasekhar, Shobana; Cook, Christopher R; Collard, Charles D

    2009-03-01

    Heart disease is the primary cause of nonobstetric mortality in pregnancy, occurring in 1%-3% of pregnancies and accounting for 10%-15% of maternal deaths. Congenital heart disease has become more prevalent in women of childbearing age, representing an increasing percentage (up to 75%) of heart disease in pregnancy. Untreated maternal heart disease also places the fetus at risk. Independent predictors of neonatal complications include a maternal New York Heart Association heart failure classification >2, anticoagulation use during pregnancy, smoking, multiple gestation, and left heart obstruction. Because cardiac surgical morbidity and mortality in the parturient is higher than nonpregnant patients, most parturients with cardiac disease are first managed medically, with cardiac surgery being reserved when medical management fails. Risk factors for maternal mortality during cardiac surgery include the use of vasoactive drugs, age, type of surgery, reoperation, and maternal functional class. Risk factors for fetal mortality include maternal age >35 yr, functional class, reoperation, emergency surgery, type of myocardial protection, and anoxic time. Nonetheless, acceptable maternal and fetal perioperative mortality rates may be achieved through such measures as early preoperative detection of maternal cardiovascular decompensation, use of fetal monitoring, delivery of a viable fetus before the operation and scheduling surgery on an elective basis during the second trimester. Additionally, fetal morbidity may be reduced during cardiopulmonary bypass by optimizing maternal oxygen-carrying capacity and uterine blood flow. Current maternal bypass recommendations include: 1) maintaining the pump flow rate >2.5 L x min(-1) x m(-2) and perfusion pressure >70 mm Hg; 2) maintaining the hematocrit > 28%; 3) using normothermic perfusion when feasible; 4) using pulsatile flow; and 5) using alpha-stat pH management. PMID:19224782

  15. Maintaining product-process balance in community antipoverty initiatives.

    PubMed

    Hannah, Gordon

    2006-01-01

    Antipoverty initiatives strive to improve distressed communities by producing outputs, such as housing, new businesses, and enhanced social services, and by building the capacity of communities to address their own problems. Although crucial for addressing the social and cultural factors contributing to community problems and for the sustainability of initiatives, capacity building is frequently set aside once implementation of initiatives begins. This article explores the funding realities, implementation demands, and power dynamics between stakeholders that result in output production being favored over capacity building. Examples from past and ongoing initiatives illustrate points and drive recommendations to help future initiatives maintain a balance between producing outputs and building capacity. PMID:16512506

  16. Cardiac Risk Assessment

    MedlinePlus

    ... helpful? Formal name: Cardiac Risk Assessment Related tests: Lipid Profile , VLDL Cholesterol , hs-CRP , Lp(a) Overview | Common ... on Coronary artery disease: Tests and diagnosis .) The lipid profile is the most important blood test for cardiac ...

  17. What Is Cardiac Rehabilitation?

    MedlinePlus

    ANSWERS by heart Treatments + Tests What Is Cardiac Rehabilitation? A cardiac rehabilitation (rehab) program takes place in a hospital or ... special help in making lifestyle changes. During your rehabilitation program you’ll… • Have a medical evaluation to ...

  18. Cardiac biomarkers in cats.

    PubMed

    Borgeat, K; Connolly, D J; Luis Fuentes, V

    2015-12-01

    Cardiac biomarkers have been used in cats as part of the clinical assessment of heart disease for over a decade. They are widely available to practitioners through commercial reference laboratories. The evidence base for the use of cardiac biomarkers (primarily N-terminal pro-B type natriuretic peptide and cardiac troponin I) in cats is comprehensively reviewed in this article, focusing on each of six specific areas: distinguishing cardiac from non-cardiac causes of respiratory distress; measurement of cardiac biomarkers in urine and pleural fluid; identification of occult cardiomyopathy; effects of systemic disease on circulating concentrations of cardiac biomarkers; point-of-care biomarker testing, and the possible prognostic utility of cardiac biomarker measurement. PMID:26776596

  19. The Estrogen Receptor-? Is Required and Sufficient to Maintain Physiological Glucose Uptake in the Mouse Heart

    PubMed Central

    Arias-Loza, Paula-Anahi; Kreissl, Michael C.; Kneitz, Susanne; Kaiser, Franz R.; Israel, Ina; Hu, Kai; Frantz, Stefan; Bayer, Barbara; Fritzemeier, Karl-Heinz; Korach, Kenneth S.; Pelzer, Theo

    2016-01-01

    Estrogens attenuate cardiac hypertrophy and increase cardiac contractility via their cognate estrogen receptors (ERs) ER? and ER?. Because female sex hormones enhance global glucose use and because myocardial function and mass are tightly linked to cardiac glucose metabolism, we tested the hypothesis that expression and activation of the ER? might be required and sufficient to maintain physiological cardiac glucose uptake in the murine heart. Cardiac glucose uptake quantified in vivo by 18F-fluorodeoxyglucose positron emission tomography was strongly impaired in ovariectomized compared with gonadal intact female C57BL/6JO mice. The selective ER? agonist 16?-LE2 and the nonselective ER? and ER? agonist 17?-estradiol completely restored cardiac glucose uptake in ovariectomized mice. Cardiac 18F-fluorodeoxyglucose uptake was strongly decreased in female ER? knockout mice compared with wild-type littermates. Analysis of cardiac mRNA accumulation by quantitative RT-PCR revealed an upregulation of genes involved in glycolisis and tricarboxylic acid cycle by ER? treatment. In conclusion, systemic activation of ER? is sufficient, and its expression is required to maintain physiological glucose uptake in the murine heart, which is likely to contribute to known cardioprotective estrogen effects. PMID:22892812

  20. Serial Input Output

    SciTech Connect

    Waite, Anthony; /SLAC

    2011-09-07

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

  1. Input-output-controlled nonlinear equation solvers

    NASA Technical Reports Server (NTRS)

    Padovan, Joseph

    1988-01-01

    To upgrade the efficiency and stability of the successive substitution (SS) and Newton-Raphson (NR) schemes, the concept of input-output-controlled solvers (IOCS) is introduced. By employing the formal properties of the constrained version of the SS and NR schemes, the IOCS algorithm can handle indefiniteness of the system Jacobian, can maintain iterate monotonicity, and provide for separate control of load incrementation and iterate excursions, as well as having other features. To illustrate the algorithmic properties, the results for several benchmark examples are presented. These define the associated numerical efficiency and stability of the IOCS.

  2. Lightweight multiple output converter development

    NASA Technical Reports Server (NTRS)

    Kisch, J. J.; Martinelli, R. M.

    1978-01-01

    A high frequency, multiple output power conditioner was developed and breadboarded using an eight-stage capacitor diode voltage multiplier to provide +1200 Vdc, and a three-stage for -350 Vdc. In addition, two rectifier bridges were capacitively coupled to the eight-stage multiplier to obtain 0.5 and 0.65 a dc constant current outputs referenced to +1200 Vdc. Total power was 120 watts, with an overall efficiency of 85 percent at the 80 kHz operating frequency. All outputs were regulated to three percent or better, with complete short circuit protection. The power conditioner component weight and efficiency were compared to the equivalent four outputs of the 10 kHz conditioner for the 8 cm ion engine. Weight reduction for the four outputs was 557 grams; extrapolated in the same ratio to all nine outputs, it would be 1100 to 1400 grams.

  3. Out of hospital cardiac arrest and associated injury.

    PubMed Central

    Jones, A I; Stuart, M J; Gray, A J

    1998-01-01

    Three patients are described who sustained injuries around the time of a collapse that led to out of hospital cardiac arrest. In this group of patients the importance of taking a complete medical history and recording the circumstances of the syncopal episode cannot be overemphasised. If cardiac output is successfully restored the possibility of occult traumatic injury must be considered in high risk patients. PMID:9639185

  4. Mechanisms of cardiac pain.

    PubMed

    Foreman, Robert D; Garrett, Kennon M; Blair, Robert W

    2015-04-01

    Angina pectoris is cardiac pain that typically is manifested as referred pain to the chest and upper left arm. Atypical pain to describe localization of the perception, generally experienced more by women, is referred to the back, neck, and/or jaw. This article summarizes the neurophysiological and pharmacological mechanisms for referred cardiac pain. Spinal cardiac afferent fibers mediate typical anginal pain via pathways from the spinal cord to the thalamus and ultimately cerebral cortex. Spinal neurotransmission involves substance P, glutamate, and transient receptor potential vanilloid-1 (TRPV1) receptors; release of neurokinins such as nuclear factor kappa b (NF-kb) in the spinal cord can modulate neurotransmission. Vagal cardiac afferent fibers likely mediate atypical anginal pain and contribute to cardiac ischemia without accompanying pain via relays through the nucleus of the solitary tract and the C1-C2 spinal segments. The psychological state of an individual can modulate cardiac nociception via pathways involving the amygdala. Descending pathways originating from nucleus raphe magnus and the pons also can modulate cardiac nociception. Sensory input from other visceral organs can mimic cardiac pain due to convergence of this input with cardiac input onto spinothalamic tract neurons. Reduction of converging nociceptive input from the gallbladder and gastrointestinal tract can diminish cardiac pain. Much work remains to be performed to discern the interactions among complex neural pathways that ultimately produce or do not produce the sensations associated with cardiac pain. PMID:25880519

  5. Controlled Cardiac Computed Tomography

    PubMed Central

    Wang, Chenglin; Liu, Ying; Wang, Ge

    2006-01-01

    Cardiac computed tomography (CT) has been a hot topic for years because of the clinical importance of cardiac diseases and the rapid evolution of CT systems. In this paper, we propose a novel strategy for controlled cardiac CT that may effectively reduce image artifacts due to cardiac and respiratory motions. Our approach is radically different from existing ones and is based on controlling the X-ray source rotation velocity and powering status in reference to the cardiac motion. We theoretically show that by such a control-based intervention the data acquisition process can be optimized for cardiac CT in the cases of periodic and quasiperiodic cardiac motions. Specifically, we formulate the corresponding coordination/control schemes for either exact or approximate matches between the ideal and actual source positions, and report representative simulation results that support our analytic findings. PMID:23165017

  6. Biological actions of green tea catechins on cardiac troponin C

    PubMed Central

    Tadano, Naoto; Du, Cheng-Kun; Yumoto, Fumiaki; Morimoto, Sachio; Ohta, Mika; Xie, Ming-Fang; Nagata, Koji; Zhan, Dong-Yun; Lu, Qun-Wei; Miwa, Yoshikazu; Takahashi-Yanaga, Fumi; Tanokura, Masaru; Ohtsuki, Iwao; Sasaguri, Toshiyuki

    2010-01-01

    BACKGROUND AND PURPOSE Catechins, biologically active polyphenols in green tea, are known to have a protective effect against cardiovascular diseases. In this study, we investigated direct actions of green tea catechins on cardiac muscle function to explore their uses as potential drugs for cardiac muscle disease. EXPERIMENTAL APPROACH The effects of catechins were systematically investigated on the force-pCa relationship in skinned cardiac muscle fibres to determine their direct effects on cardiac myofilament contractility. The mechanisms of action of effective catechins were investigated using troponin exchange techniques, quartz crystal microbalance, nuclear magnetic resonance and a transgenic mouse model. KEY RESULTS (-)-Epicatechin-3-gallate (ECg) and (-)-epigallocatechin-3-gallate (EGCg), but not their stereoismers (-)-catechin-3-gallate and (-)-gallocatechin-3-gallate, decreased cardiac myofilament Ca2+ sensitivity probably through its interaction with cardiac troponin C. EGCg restored cardiac output in isolated working hearts by improving diastolic dysfunction caused by increased myofilament Ca2+ sensitivity in a mouse model of hypertrophic cardiomyopathy. CONCLUSIONS AND IMPLICATIONS The green tea catechins, ECg and EGCg, are Ca2+ desensitizers acting through binding to cardiac troponin C. These compounds might be useful compounds for the development of therapeutic agents to treat the hypertrophic cardiomyopathy caused by increased Ca2+ sensitivity of cardiac myofilaments. PMID:20977454

  7. Enhanced performance CCD output amplifier

    DOEpatents

    Dunham, Mark E.; Morley, David W.

    1996-01-01

    A low-noise FET amplifier is connected to amplify output charge from a che coupled device (CCD). The FET has its gate connected to the CCD in common source configuration for receiving the output charge signal from the CCD and output an intermediate signal at a drain of the FET. An intermediate amplifier is connected to the drain of the FET for receiving the intermediate signal and outputting a low-noise signal functionally related to the output charge signal from the CCD. The amplifier is preferably connected as a virtual ground to the FET drain. The inherent shunt capacitance of the FET is selected to be at least equal to the sum of the remaining capacitances.

  8. Anesthesia with propofol induces insulin resistance systemically in skeletal and cardiac muscles and liver of rats

    SciTech Connect

    Yasuda, Yoshikazu; Fukushima, Yuji; Kaneki, Masao; Martyn, J.A. Jeevendra

    2013-02-01

    Highlights: ► Propofol, as a model anesthetic drug, induced whole body insulin resistance. ► Propofol anesthesia decreased glucose infusion rate to maintain euglycemia. ► Propofol decreased insulin-mediated glucose uptake in skeletal and cardiac muscles. ► Propofol increased hepatic glucose output confirming hepatic insulin resistance. -- Abstract: Hyperglycemia together with hepatic and muscle insulin resistance are common features in critically ill patients, and these changes are associated with enhanced inflammatory response, increased susceptibility to infection, muscle wasting, and worsened prognosis. Tight blood glucose control by intensive insulin treatment may reduce the morbidity and mortality in intensive care units. Although some anesthetics have been shown to cause insulin resistance, it remains unknown how and in which tissues insulin resistance is induced by anesthetics. Moreover, the effects of propofol, a clinically relevant intravenous anesthetic, also used in the intensive care unit for sedation, on insulin sensitivity have not yet been investigated. Euglycemic hyperinsulinemic clamp study was performed in rats anesthetized with propofol and conscious unrestrained rats. To evaluate glucose uptake in tissues and hepatic glucose output [{sup 3}H]glucose and 2-deoxy[{sup 14}C]glucose were infused during the clamp study. Anesthesia with propofol induced a marked whole-body insulin resistance compared with conscious rats, as reflected by significantly decreased glucose infusion rate to maintain euglycemia. Insulin-stimulated tissue glucose uptake was decreased in skeletal muscle and heart, and hepatic glucose output was increased in propofol anesthetized rats. Anesthesia with propofol induces systemic insulin resistance along with decreases in insulin-stimulated glucose uptake in skeletal and heart muscle and attenuation of the insulin-mediated suppression of hepatic glucose output in rats.

  9. Stimulating endogenous cardiac repair

    PubMed Central

    Finan, Amanda; Richard, Sylvain

    2015-01-01

    The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration, a combination of these approaches could ameliorate the overall repair process to incorporate the participation of multiple cellular players. PMID:26484341

  10. Stimulating endogenous cardiac repair.

    PubMed

    Finan, Amanda; Richard, Sylvain

    2015-01-01

    The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration, a combination of these approaches could ameliorate the overall repair process to incorporate the participation of multiple cellular players. PMID:26484341

  11. Doppler echocardiography: Quantitative methods of pulsed and continuous wave cardiac doppler

    SciTech Connect

    Labovitz, A.J.; Williams, G.A.

    1985-01-01

    This book is written in workbook format and presents basic physical principles involved in the Doppler flow velocity recording in both normal and abnormal states. Formulas necessary in the computation of valve gradients, valve areas, and cardiac outputs are included.

  12. Peru struggles to maintain crude production

    SciTech Connect

    Not Available

    1991-01-14

    Revival of Peru's moribund oil and gas industry in the 1990s hinges on whether the new administration of President Alberto Fujimori is successful in attracting foreign investment in Peru. Fujimori's success would mean Peru pushing ahead into stepped up exploration and major development projects, such as the huge Camisea gas/condensate field discovered 2 years ago. His failure could mean Peru continuing to fall further behind in its already lagging low oil production. Huge sums of money will be needed. Peru also needs to succeed in its efforts to become creditworthy again for international agencies, foreign governments, and commercial banks. Meanwhile, Petroleos del Peru SA (Petroperu), the state oil company, will have to transfer an increasing share of its operations to private investors. But the company is likely to try to hold onto producing fields, even though it is unable to maintain full output.

  13. Tips to Maintain Good Posture

    MedlinePlus

    ... Gardening Chronic Pain and Depression Tips to Maintain Good Posture We often hear that good posture is ... our posture and balance during movement. Why is good posture important? Good posture helps us stand, walk, ...

  14. Simple Fixed Functional Space Maintainer

    PubMed Central

    Sarawgi, Aditi; Marwah, Nikhil; Gumber, Parvind; Dutta, Samir

    2014-01-01

    ABSTRACT% Premature loss of a primary tooth is one of the most common etiology for malocclusion. Space maintainers are employed to prevent this complication. In anterior region, esthetics is an important concern along with function and space management. Fiber-reinforced composite (FRC) retained space maintainer solves all these purposes ef ficiently and ef fectively. In addition, the technique is simple and the appliance is very comfortable inside the oral cavity. Here is a case of premature loss of anterior primary tooth which was replaced by FRC retained esthetic functional space maintainer. The appliance was found to be functioning satisfactorily inside the oral cavity till the last visit (1 Year). How to cite this article: Goenka P, Sarawgi A, Marwah N, Gumber P, Dutta S. Simple Fixed Functional Space Maintainer. Int J Clin Pediatr Dent 2014;7(3):225-228. PMID:25709309

  15. Cardiac Extracellular Vesicles in Normal and Infarcted Heart

    PubMed Central

    Chistiakov, Dimitry A.; Orekhov, Alexander N.; Bobryshev, Yuri V.

    2016-01-01

    Heart is a complex assembly of many cell types constituting myocardium, endocardium and epicardium that intensively communicate to each other in order to maintain the proper cardiac function. There are many types of intercellular intracardiac signals, with a prominent role of extracellular vesicles (EVs), such as exosomes and microvesicles, for long-distant delivering of complex messages. Cardiomyocytes release EVs, whose content could significantly vary depending on the stimulus. In stress, such as hypoxia, inflammation or injury, cardiomyocytes increase secretion of EVs. In hypoxic conditions, cardiac EVs are enriched with angiogenic and prosurvival factors. In acute myocardial infarction (AMI), damaged cardiac muscle cells produce EVs with increased content of angiogenic, anti-apoptotic, mitogenic and growth factors in order to induce repair and healing of the infarcted myocardium. Exosomal microRNAs play a central role in cardiac regeneration. In AMI, circulating cardiac EVs abundantly contain cardiac-specific miRNAs that serve as indicators of cardiac damage and have a big diagnostic potential as AMI biomarkers. Cardioprotective and regenerative properties of exosomes derived from cardiac and non-cardiac stem/progenitor cells are very helpful to be used in cell-free cardiotherapy and regeneration of post-infarct myocardium. PMID:26742038

  16. Cardiac Extracellular Vesicles in Normal and Infarcted Heart.

    PubMed

    Chistiakov, Dimitry A; Orekhov, Alexander N; Bobryshev, Yuri V

    2016-01-01

    Heart is a complex assembly of many cell types constituting myocardium, endocardium and epicardium that intensively communicate to each other in order to maintain the proper cardiac function. There are many types of intercellular intracardiac signals, with a prominent role of extracellular vesicles (EVs), such as exosomes and microvesicles, for long-distant delivering of complex messages. Cardiomyocytes release EVs, whose content could significantly vary depending on the stimulus. In stress, such as hypoxia, inflammation or injury, cardiomyocytes increase secretion of EVs. In hypoxic conditions, cardiac EVs are enriched with angiogenic and prosurvival factors. In acute myocardial infarction (AMI), damaged cardiac muscle cells produce EVs with increased content of angiogenic, anti-apoptotic, mitogenic and growth factors in order to induce repair and healing of the infarcted myocardium. Exosomal microRNAs play a central role in cardiac regeneration. In AMI, circulating cardiac EVs abundantly contain cardiac-specific miRNAs that serve as indicators of cardiac damage and have a big diagnostic potential as AMI biomarkers. Cardioprotective and regenerative properties of exosomes derived from cardiac and non-cardiac stem/progenitor cells are very helpful to be used in cell-free cardiotherapy and regeneration of post-infarct myocardium. PMID:26742038

  17. Enhancing Cardiac Triacylglycerol Metabolism Improves Recovery From Ischemic Stress.

    PubMed

    Kolwicz, Stephen C; Liu, Li; Goldberg, Ira J; Tian, Rong

    2015-08-01

    Elevated cardiac triacylglycerol (TAG) content is traditionally equated with cardiolipotoxicity and suggested to be a culprit in cardiac dysfunction. However, previous work demonstrated that myosin heavy-chain-mediated cardiac-specific overexpression of diacylglycerol transferase 1 (MHC-DGAT1), the primary enzyme for TAG synthesis, preserved cardiac function in two lipotoxic mouse models despite maintaining high TAG content. Therefore, we examined whether increased cardiomyocyte TAG levels due to DGAT1 overexpression led to changes in cardiac TAG turnover rates under normoxia and ischemia-reperfusion conditions. MHC-DGAT1 mice had elevated TAG content and synthesis rates, which did not alter cardiac function, substrate oxidation, or myocardial energetics. MHC-DGAT1 hearts had ischemia-induced lipolysis; however, when a physiologic mixture of long-chain fatty acids was provided, enhanced TAG turnover rates were associated with improved functional recovery from low-flow ischemia. Conversely, exogenous supply of palmitate during reperfusion suppressed elevated TAG turnover rates and impaired recovery from ischemia in MHC-DGAT1 hearts. Collectively, this study shows that elevated TAG content, accompanied by enhanced turnover, does not adversely affect cardiac function and, in fact, provides cardioprotection from ischemic stress. In addition, the results highlight the importance of exogenous supply of fatty acids when assessing cardiac lipid metabolism and its relationship with cardiac function. PMID:25858561

  18. Blunt Cardiac Injury.

    PubMed

    Marcolini, Evie G; Keegan, Joshua

    2015-08-01

    Blunt cardiac injury encompasses multiple different injuries, including contusion, chamber rupture, and acute valvular disorders. Blunt cardiac injury is common and may cause significant morbidity and mortality; a high index of suspicion is needed for accurate diagnosis. Diagnostic work-up should always include electrocardiogram and cardiac enzymes, and may include echocardiography if specific disorders (ie, tamponade or valvular disorders) are suspected. Patients with myocardial contusion should be observed for 24 to 48 hours for arrhythmias. Many other significant forms of blunt cardiac injury require surgical intervention. PMID:26226863

  19. Cardiac Stem Cell Niches

    PubMed Central

    Leri, Annarosa; Rota, Marcello; Hosoda, Toru; Goichberg, Polina; Anversa, Piero

    2014-01-01

    The critical role that stem cell niches have in cardiac homeostasis and myocardial repair following injury is the focus of this review. Cardiac niches represent specialized microdomains where the quiescent and activated state of resident stem cells is regulated. Alterations in niche function with aging and cardiac diseases result in abnormal sites of cardiomyogenesis and inadequate myocyte formation. The relevance of Notch 1 signaling, gap-junction formation, HIF-1? and metabolic state in the regulation of stem cell growth and differentiation within the cardiac niches are discussed. PMID:25267073

  20. [Sexuality and cardiac arrhythmias].

    PubMed

    Sztajzel, J

    2013-03-20

    For most patients, sexual activity represents a low risk of triggering cardiac arrhythmias. However, particularly in patients with an underlying heart disease, sexual activity may cause cardiac arrhythmias which may be sometimes serious. From a physiological point of view, sexual activity produces increased sympathetic activity and thereby probably reduced vagal tone which at different degrees may induce cardiac arrythmias. Several presently available autopsy-studies have shown that this happens very rarely and that it mostly affects men. Finally, recently published recommendations allow us to better advise patients with cardiac arrhytmias to engage in sexual activity or to defer it until the condition is stabilized and optimally controlled. PMID:23547362

  1. Vagus nerve stimulation mitigates intrinsic cardiac neuronal remodeling and cardiac hypertrophy induced by chronic pressure overload in guinea pig.

    PubMed

    Beaumont, Eric; Wright, Gary L; Southerland, Elizabeth M; Li, Ying; Chui, Ray; KenKnight, Bruce H; Armour, J Andrew; Ardell, Jeffrey L

    2016-05-15

    Our objective was to determine whether chronic vagus nerve stimulation (VNS) mitigates pressure overload (PO)-induced remodeling of the cardioneural interface. Guinea pigs (n = 48) were randomized to right or left cervical vagus (RCV or LCV) implant. After 2 wk, chronic left ventricular PO was induced by partial (15-20%) aortic constriction. Of the 31 animals surviving PO induction, 10 were randomized to RCV VNS, 9 to LCV VNS, and 12 to sham VNS. VNS was delivered at 20 Hz and 1.14 ± 0.03 mA at a 22% duty cycle. VNS commenced 10 days after PO induction and was maintained for 40 days. Time-matched controls (n = 9) were evaluated concurrently. Echocardiograms were obtained before and 50 days after PO. At termination, intracellular current-clamp recordings of intrinsic cardiac (IC) neurons were studied in vitro to determine effects of therapy on soma characteristics. Ventricular cardiomyocyte sizes were assessed with histology along with immunoblot analysis of selected proteins in myocardial tissue extracts. In sham-treated animals, PO increased cardiac output (34%, P < 0.004), as well as systolic (114%, P < 0.04) and diastolic (49%, P < 0.002) left ventricular volumes, a hemodynamic response prevented by VNS. PO-induced enhancements of IC synaptic efficacy and muscarinic sensitivity of IC neurons were mitigated by chronic VNS. Increased myocyte size, which doubled in PO (P < 0.05), was mitigated by RCV. PO hypertrophic myocardium displayed decreased glycogen synthase (GS) protein levels and accumulation of the phosphorylated (inactive) form of GS. These PO-induced changes in GS were moderated by left VNS. Chronic VNS targets IC neurons accompanying PO to obtund associated adverse cardiomyocyte remodeling. PMID:26993230

  2. Research on output feedback control

    NASA Technical Reports Server (NTRS)

    Calise, Anthony J.

    1988-01-01

    A summary is presented of the main results obtained during the course of research on output feedback control. The term output feedback is used to denote a controller design approach which does not rely on an observer to estimate the states of the system. Thus, the order of the controller is fixed, and can even be zero order, which amounts to constant gain ouput feedback. The emphasis has been on optimal output feedback. That is, a fixed order controller is designed based on minimizing a suitably chosen quadratic performance index. A number of problem areas that arise in this context have been addressed. These include developing suitable methods for selecting an index of performance, both time domain and frequency domain methods for achieving robustness of the closed loop system, developing canonical forms to achieve a minimal parameterization for the controller, two time scale design formulations for ill-conditioned systems, and the development of convergent numerical algorithms for solving the output feedback problem.

  3. Output optics for laser velocimeters

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  4. New approach for simultaneous respiratory and cardiac motion correction in cardiac PET (NAMC-CPET)

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohamed A. A.; Xiao, Peng; Xie, Qingguo

    2015-10-01

    Respiratory and cardiac motions are inevitable during the relatively long acquisition time of cardiac positron emission tomography (PET) scan. The correction of the resultant motion blur has become a significant challenge due to recent spatial resolution improvement of the PET scanners. The majority of current motion compensation algorithms are based on gating as a primary step. A new approach based on temporal basis functions is developed to correct respiratory and cardiac motion simultaneously in cardiac PET within the normal scanning time (NAMC-CPET). Simulation and experimental studies are conducted to evaluate and validate the final outputs in comparison to the existing gating methods. A dynamic digital phantom is used to simulate realistic human thorax and abdomen with respiratory and cardiac motions. GATE simulation was run at China National Grid Center to obtain realistic PET data in a reasonable time. Moreover, Tibet minipig experiments were conducted using a preclinical small animal PET scanner developed at HUST to validate the performance of the NAMC-CPET in real data. The results reveal that NAMC-CPET outperformed the existing gating methods (respiratory, cardiac, and dual) in cardiac imaging in term of noise reduction and contrast, especially in short acquisition duration. NAMC-CPET obtained better results in the conducted experiments in terms of contrast and the visibility of the heart. In contrast, the dual gating failed to obtain valuable images in the normal scan time due to the low 18F-FDG uptake. NAMC-CPET is advantageous in the low-statistic situation. The results are promising with great potential implications in cardiac PET imaging in terms of the radioactive dose and scan time reduction.

  5. New approach for simultaneous respiratory and cardiac motion correction in cardiac PET (NAMC-CPET).

    PubMed

    Ahmed, Mohamed A A; Xiao, Peng; Xie, Qingguo

    2015-10-01

    Respiratory and cardiac motions are inevitable during the relatively long acquisition time of cardiac positron emission tomography (PET) scan. The correction of the resultant motion blur has become a significant challenge due to recent spatial resolution improvement of the PET scanners. The majority of current motion compensation algorithms are based on gating as a primary step. A new approach based on temporal basis functions is developed to correct respiratory and cardiac motion simultaneously in cardiac PET within the normal scanning time (NAMC-CPET). Simulation and experimental studies are conducted to evaluate and validate the final outputs in comparison to the existing gating methods. A dynamic digital phantom is used to simulate realistic human thorax and abdomen with respiratory and cardiac motions. GATE simulation was run at China National Grid Center to obtain realistic PET data in a reasonable time. Moreover, Tibet minipig experiments were conducted using a preclinical small animal PET scanner developed at HUST to validate the performance of the NAMC-CPET in real data. The results reveal that NAMC-CPET outperformed the existing gating methods (respiratory, cardiac, and dual) in cardiac imaging in term of noise reduction and contrast, especially in short acquisition duration. NAMC-CPET obtained better results in the conducted experiments in terms of contrast and the visibility of the heart. In contrast, the dual gating failed to obtain valuable images in the normal scan time due to the low 18F-FDG uptake. NAMC-CPET is advantageous in the low-statistic situation. The results are promising with great potential implications in cardiac PET imaging in terms of the radioactive dose and scan time reduction. PMID:26393382

  6. Established and emerging dose reduction methods in cardiac computed tomography.

    PubMed

    Small, Gary R; Kazmi, Mustapha; Dekemp, Robert A; Chow, Benjamin J W

    2011-08-01

    Cardiac computed tomography (CT) is a non-invasive modality that is commonly used as an alternative to invasive coronary angiography for the investigation of coronary artery disease. The enthusiasm for this technology has been tempered by a growing appreciation of the potential risks of malignancy associated with the use of ionising radiation. In the spirit of minimizing patient risk, the medical profession and industry have worked hard to developed methods and protocols to reduce patient radiation exposure while maintaining excellent diagnostic accuracy. A complete understanding of radiation reduction techniques will allow clinicians to reduce patient risk while providing an important diagnostic service. This review will consider the established and emerging techniques that may be adopted to reduce patient absorbed doses from x-ray CT. By modifying (1) x-ray tube output, (2) imaging time (scan duration), (3) imaging distance (scan length) and (4) the appropriate use of shielding, clinicians will be able to adhere to the 'as low as reasonably achievable (ALARA)' principle. PMID:21630110

  7. Sudden Cardiac Death

    PubMed Central

    Weinberg, Marc

    1978-01-01

    Over the past decade, there has been a significant decrease in the hospital mortality of patients with coronary artery disease. However, sudden cardiac death, which accounts for the majority of deaths from coronary artery disease, hasbeen little affected. This report reviews the pathology, electrophysiology, demographics and clinical presentation of sudden cardiac death. Emergency care and possible preventative measures are examined. PMID:356435

  8. PGC-1 coactivators in cardiac development and disease

    PubMed Central

    Rowe, Glenn C.; Jiang, Aihua; Arany, Zolt

    2010-01-01

    The beating heart requires a constant flux of ATP to maintain contractile function, and there is increasing evidence that energetic defects contribute to the development of heart failure. The last ten years have seen a resurgent interest in cardiac intermediary metabolism, and a dramatic increase in our understanding of transcriptional networks that regulate cardiac energetics. The PPAR-gamma coactivator (PGC)-1 family of proteins plays a central role in these pathways. The mechanisms by which PGC-1 proteins regulate transcriptional networks and are regulated by physiological cues, and the roles they play in cardiac development and disease, are reviewed here. PMID:20884884

  9. Maintaining Chaos in High Dimensions

    NASA Astrophysics Data System (ADS)

    in, Visarath; Spano, Mark L.; Ding, Mingzhou

    1998-01-01

    In dynamical systems, as a parameter is varied past a critical value, a chaotic attractor may be destroyed by a crisis. This attractor is replaced by a chaotic transient, which eventually leads to a different attractor. We present a method for maintaining chaotic dynamics after the crisis. The model, formulated for arbitrary dimensions, directs the phase space trajectory toward a target region near the periodic saddle orbit that mediates the crisis. It is used to maintain chaos numerically in the Ikeda map and experimentally in a magnetoelastic ribbon.

  10. Maintaining qualification for 340B.

    PubMed

    Gricius, Robert F; Wong, Douglas

    2016-03-01

    After initial acceptance in the 340B Drug Pricing Program, hospitals and health systems should monitor and take steps to maintain their disproportionate share hospital status to continue to qualify for participation. Proactively managing the Supplemental Security Income (SSI) Ratio will ensure the organization avoids an unexpected decline in the Medicare portion of its 340B patient base. Even with the surge resulting from Medicaid expansion, tracking patient eligibility for Medicare/ SSI to ensure all patients who qualify are appropriately enrolled in the program is an important step in maintaining 340B program eligibility. PMID:27183761

  11. Radiation Propulsion For Maintaining Orbits

    NASA Technical Reports Server (NTRS)

    Richter, Robert

    1995-01-01

    Brief report proposes radiative propulsion systems for maintaining precise orbits of spacecraft. Radiation from electrical heaters directed outward by paraboloidal reflectors to produce small forces to oppose uncontrolled drag and solar-radiative forces perturbing orbits. Minimizes or eliminates need to fire rocket thrusters to correct orbits.

  12. Strategies for Maintaining Community Integration.

    ERIC Educational Resources Information Center

    Gruber, Fred

    1986-01-01

    This article outlines strategies of maintaining integration emphasizing: (1) housing offices and counseling; (2) community action to alter real estate policies; (3) school action including public relations and human relations thinking; (4) community organization of commercial and religious institutions; (5) financial incentives for pro-integrative…

  13. [Maintaining patients' autonomy at home].

    PubMed

    Niang, Bénédicte; Coudre, Jean Pierre

    2015-01-01

    To maintain the flow of hospital discharges, the patient's return home with support from a home nursing service is important. If any difficulties are identified, there are various programmes or good practices which can be put into place. The future law on adapting society to ageing also comprises a scheme combining home assistance and nursing care. PMID:26144953

  14. Maintaining Sustainability for Green Schools

    ERIC Educational Resources Information Center

    Kennedy, Mike

    2011-01-01

    The promise of sustainably designed school facilities is that they will operate more efficiently and last longer than buildings constructed in more traditional ways. But that promise comes with a big if. The payoff is delivered only if the facility managers operate and maintain the buildings in ways that adhere to sustainable strategies called for…

  15. Experimental characterization of variable output refractive beamshapers using freeform elements

    NASA Astrophysics Data System (ADS)

    Shultz, Jason A.; Smilie, Paul J.; Dutterer, Brian S.; Davies, Matthew A.; Suleski, Thomas J.

    2014-09-01

    We present experimental results from variable output refractive beam shapers based on freeform optical surfaces. Two freeform elements in close proximity comprise a beam shaper that maps a circular Gaussian input to a circular `flat-top' output. Different lateral relative shifts between the elements result in a varying output diameter while maintaining the uniform irradiance distribution. We fabricated the beam shaping elements in PMMA using multi-axis milling on a Moore Nanotech 350FG diamond machining center and tested with a 632.8 nm Gaussian input. Initial optical testing confirmed both the predicted beam shaping and variable functionality, but with poor output uniformity. The effects of surface finish on optical performance were investigated using LightTrans VirtualLabTM to perform physical optics simulations of the milled freeform surfaces. These simulations provided an optimization path for determining machining parameters to improve the output uniformity of the beam shaping elements. A second variable beam shaper based on a super-Gaussian output was designed and fabricated using the newly determined machining parameters. Experimental test results from the second beam shaper showed outputs with significantly higher quality, but also suggest additional areas of study for further improvements in uniformity.

  16. Characterization of a flow-through microcalorimeter for measuring the heat production of cardiac trabeculae

    NASA Astrophysics Data System (ADS)

    Taberner, A. J.; Hunter, I. W.; Kirton, R. S.; Nielsen, P. M. F.; Loiselle, D. S.

    2005-10-01

    The energy consumption of isolated cardiac trabeculae can be inferred from measurements of their heat production. Once excised from the heart, to remain viable, trabeculae require continuous superfusion with an oxygen- and nutrient-rich solution. Flow-through calorimeters enable trabeculae to be maintained in a stable and controlled environment for many hours at a time. In this paper we describe and characterize a flow-through microcalorimeter, with sensitivity in the 1μW range, for measuring the heat output of 10μg cardiac trabeculae. The device uses infrared-sensitive, thin-film thermopile sensors to provide a noncontact method for measuring temperature differences. The sensors are capable of resolving 5μK temperature differences within the superfusing fluid. The microcalorimeter has a sensitivity of 2.56V/W at a flow rate of 1μl/s, with a time constant of approximately 3.5 s. The sensitivity and time constant are strongly dependent upon the flow rate. Predictions of a finite-element model of the calorimeter's characteristics compare favorably with measured data over a wide range of flow rates.

  17. CARFMAP: A Curated Pathway Map of Cardiac Fibroblasts.

    PubMed

    Nim, Hieu T; Furtado, Milena B; Costa, Mauro W; Kitano, Hiroaki; Rosenthal, Nadia A; Boyd, Sarah E

    2015-01-01

    The adult mammalian heart contains multiple cell types that work in unison under tightly regulated conditions to maintain homeostasis. Cardiac fibroblasts are a significant and unique population of non-muscle cells in the heart that have recently gained substantial interest in the cardiac biology community. To better understand this renaissance cell, it is essential to systematically survey what has been known in the literature about the cellular and molecular processes involved. We have built CARFMAP (http://visionet.erc.monash.edu.au/CARFMAP), an interactive cardiac fibroblast pathway map derived from the biomedical literature using a software-assisted manual data collection approach. CARFMAP is an information-rich interactive tool that enables cardiac biologists to explore the large body of literature in various creative ways. There is surprisingly little overlap between the cardiac fibroblast pathway map, a foreskin fibroblast pathway map, and a whole mouse organism signalling pathway map from the REACTOME database. Among the use cases of CARFMAP is a common task in our cardiac biology laboratory of identifying new genes that are (1) relevant to cardiac literature, and (2) differentially regulated in high-throughput assays. From the expression profiles of mouse cardiac and tail fibroblasts, we employed CARFMAP to characterise cardiac fibroblast pathways. Using CARFMAP in conjunction with transcriptomic data, we generated a stringent list of six genes that would not have been singled out using bioinformatics analyses alone. Experimental validation showed that five genes (Mmp3, Il6, Edn1, Pdgfc and Fgf10) are differentially regulated in the cardiac fibroblast. CARFMAP is a powerful tool for systems analyses of cardiac fibroblasts, facilitating systems-level cardiovascular research. PMID:26673252

  18. CARFMAP: A Curated Pathway Map of Cardiac Fibroblasts

    PubMed Central

    Nim, Hieu T.; Furtado, Milena B.; Costa, Mauro W.; Kitano, Hiroaki; Rosenthal, Nadia A.; Boyd, Sarah E.

    2015-01-01

    The adult mammalian heart contains multiple cell types that work in unison under tightly regulated conditions to maintain homeostasis. Cardiac fibroblasts are a significant and unique population of non-muscle cells in the heart that have recently gained substantial interest in the cardiac biology community. To better understand this renaissance cell, it is essential to systematically survey what has been known in the literature about the cellular and molecular processes involved. We have built CARFMAP (http://visionet.erc.monash.edu.au/CARFMAP), an interactive cardiac fibroblast pathway map derived from the biomedical literature using a software-assisted manual data collection approach. CARFMAP is an information-rich interactive tool that enables cardiac biologists to explore the large body of literature in various creative ways. There is surprisingly little overlap between the cardiac fibroblast pathway map, a foreskin fibroblast pathway map, and a whole mouse organism signalling pathway map from the REACTOME database. Among the use cases of CARFMAP is a common task in our cardiac biology laboratory of identifying new genes that are (1) relevant to cardiac literature, and (2) differentially regulated in high-throughput assays. From the expression profiles of mouse cardiac and tail fibroblasts, we employed CARFMAP to characterise cardiac fibroblast pathways. Using CARFMAP in conjunction with transcriptomic data, we generated a stringent list of six genes that would not have been singled out using bioinformatics analyses alone. Experimental validation showed that five genes (Mmp3, Il6, Edn1, Pdgfc and Fgf10) are differentially regulated in the cardiac fibroblast. CARFMAP is a powerful tool for systems analyses of cardiac fibroblasts, facilitating systems-level cardiovascular research. PMID:26673252

  19. The optimal hemodynamics management of post-cardiac arrest shock.

    PubMed

    Pellis, Tommaso; Sanfilippo, Filippo; Ristagno, Giuseppe

    2015-12-01

    Patients resuscitated from cardiac arrest develop a pathophysiological state named "post-cardiac arrest syndrome." Post-resuscitation myocardial dysfunction is a common feature of this syndrome, and many patients eventually die from cardiovascular failure. Cardiogenic shock accounts for most deaths in the first 3 days, when post-resuscitation myocardial dysfunction peaks. Thus, identification and treatment of cardiovascular failure is one of the key therapeutic goals during hospitalization of post-cardiac arrest patients. Patients with hemodynamic instability may require advanced cardiac output monitoring. Inotropes and vasopressors should be considered if hemodynamic goals are not achieved despite optimized preload. If these measures fail to restore adequate organ perfusion, a mechanical circulatory assistance device may be considered. Adequate organ perfusion should be ensured in the absence of definitive data on the optimal target pressure goals. Hemodynamic goals should also take into account targeted temperature management and its effect on the cardiovascular function. PMID:26670819

  20. Naturally occurring cardiac glycosides.

    PubMed

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

    1986-05-12

    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

  1. Living cardiac tissue slices: an organotypic pseudo two-dimensional model for cardiac biophysics research.

    PubMed

    Wang, Ken; Terrar, Derek; Gavaghan, David J; Mu-U-Min, Razik; Kohl, Peter; Bollensdorff, Christian

    2014-08-01

    Living cardiac tissue slices, a pseudo two-dimensional (2D) preparation, have received less attention than isolated single cells, cell cultures, or Langendorff-perfused hearts in cardiac biophysics research. This is, in part, due to difficulties associated with sectioning cardiac tissue to obtain live slices. With moderate complexity, native cell-types, and well-preserved cell-cell electrical and mechanical interconnections, cardiac tissue slices have several advantages for studying cardiac electrophysiology. The trans-membrane potential (Vm) has, thus far, mainly been explored using multi-electrode arrays. Here, we combine tissue slices with optical mapping to monitor Vm and intracellular Ca(2+) concentration ([Ca(2+)]i). This combination opens up the possibility of studying the effects of experimental interventions upon action potential (AP) and calcium transient (CaT) dynamics in 2D, and with relatively high spatio-temporal resolution. As an intervention, we conducted proof-of-principle application of stretch. Mechanical stimulation of cardiac preparations is well-established for membrane patches, single cells and whole heart preparations. For cardiac tissue slices, it is possible to apply stretch perpendicular or parallel to the dominant orientation of cells, while keeping the preparation in a constant focal plane for fluorescent imaging of in-slice functional dynamics. Slice-to-slice comparison furthermore allows one to assess transmural differences in ventricular tissue responses to mechanical challenges. We developed and tested application of axial stretch to cardiac tissue slices, using a manually-controlled stretching device, and recorded Vm and [Ca(2+)]i by optical mapping before, during, and after application of stretch. Living cardiac tissue slices, exposed to axial stretch, show an initial shortening in both AP and CaT duration upon stretch application, followed in most cases by a gradual prolongation of AP and CaT duration during stretch maintained for up to 50 min. After release of sustained stretch, AP duration (APD) and CaT duration reverted to shorter values. Living cardiac tissue slices are a promising experimental model for the study of cardiac mechano-electric interactions. The methodology described here can be refined to achieve more accurate control over stretch amplitude and timing (e.g. using a computer-controlled motorised stage, or by synchronising electrical and mechanical events) and through monitoring of regional tissue deformation (e.g. by adding motion tracking). PMID:25124067

  2. World Input-Output Network.

    PubMed

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  3. World Input-Output Network

    PubMed Central

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  4. Classroom Interaction and Language Output

    ERIC Educational Resources Information Center

    Wang, Qiaoying; Castro, Carolyn D.

    2010-01-01

    This study investigates the effects of classroom interactions between a) students and students and b) students and teachers on the learning of English passivization by L1 Chinese adult learners of English as a foreign language during the language input and output treatments. In phase 1, both groups were asked to read and underline the input…

  5. Coral Mortality and Bleaching Output

    EPA Science Inventory

    COMBO is a spreadsheet-based model for the use of managers, conservationists, and biologists for projecting the effects of climate change on coral reefs at local-to-regional scales. The COMBO (Coral Mortality and Bleaching Output) model calculates the impacts to coral reefs from...

  6. Cardiac Arrest Resuscitation.

    PubMed

    Guyette, Francis X; Reynolds, Joshua C; Frisch, Adam

    2015-08-01

    Cardiac arrest is a dynamic disease that tests the multitasking and leadership abilities of emergency physicians. Providers must simultaneously manage the logistics of resuscitation while searching for the cause of cardiac arrest. The astute clinician will also realize that he or she is orchestrating only one portion of a larger series of events, each of which directly affects patient outcomes. Resuscitation science is rapidly evolving, and emergency providers must be familiar with the latest evidence and controversies surrounding resuscitative techniques. This article reviews evidence, discusses controversies, and offers strategies to provide quality cardiac arrest resuscitation. PMID:26226873

  7. [Cardiac Rehabilitation 2015].

    PubMed

    Hoffmann, Andreas

    2015-11-25

    The goals of cardiac rehabilitation are (re-)conditioning and secondary prevention in patients with heart disease or an elevated cardiovascular risk profile. Rehabilitation is based on motivation through education, on adapted physical activity, instruction of relaxation techniques, psychological support and optimized medication. It is performed preferably in groups either in outpatient or inpatient settings. The Swiss working group on cardiac rehabilitation provides a network of institutions with regular quality auditing. Positive effects of rehabilitation programs on mortality and morbidity have been established by numerous studies. Although a majority of patients after cardiac surgery are being referred to rehabilitation, these services are notoriously underused after catheter procedures. PMID:26602848

  8. Maintaining steam/condensate lines

    SciTech Connect

    Russum, S.A. )

    1992-03-05

    Steam and condensate systems must be maintained with the same diligence as the boiler itself. Unfortunately, they often are not. The water treatment program, critical to keeping the boiler at peak efficiency and optimizing operating life, should not stop with the boiler. The program must encompass the steam and condensate system as well. A properly maintained condensate system maximizes condensate recovery, which is a cost-free energy source. The fuel needed to turn the boiler feedwater into steam has already been provided. Returning the condensate allows a significant portion of that fuel cost to be recouped. Condensate has a high heat content. Condensate is a readily available, economical feedwater source. Properly treated, it is very pure. Condensate improves feedwater quality and reduces makeup water demand and pretreatment costs. Higher quality feedwater means more reliable boiler operation.

  9. Disturbance maintains alternative biome states.

    PubMed

    Dantas, Vinícius de L; Hirota, Marina; Oliveira, Rafael S; Pausas, Juli G

    2016-01-01

    Understanding the mechanisms controlling the distribution of biomes remains a challenge. Although tropical biome distribution has traditionally been explained by climate and soil, contrasting vegetation types often occur as mosaics with sharp boundaries under very similar environmental conditions. While evidence suggests that these biomes are alternative states, empirical broad-scale support to this hypothesis is still lacking. Using community-level field data and a novel resource-niche overlap approach, we show that, for a wide range of environmental conditions, fire feedbacks maintain savannas and forests as alternative biome states in both the Neotropics and the Afrotropics. In addition, wooded grasslands and savannas occurred as alternative grassy states in the Afrotropics, depending on the relative importance of fire and herbivory feedbacks. These results are consistent with landscape scale evidence and suggest that disturbance is a general factor driving and maintaining alternative biome states and vegetation mosaics in the tropics. PMID:26493189

  10. Cardiac temperature and cardioplegic volume during cardiopulmonary bypass.

    PubMed

    Baile, E M; Ling, H; Miyagishima, R T; Kronhardt, H; Par, P D

    1986-10-01

    This study was designed to compare two methods of cardiac drainage on the rate of change of cardiac temperature and volume of cardioplegic solution required to maintain the cardiac temperature less than or equal to 12 degrees C in patients undergoing coronary artery bypass surgery. Two groups of 10 patients were studied who were comparable in age, sex, and smoking history. In Group 1, cardiac drainage was achieved by using single-port drainage cannulae in the superior and inferior vena cava with caval tapes. Group 2 patients had a caval atrial cannula to drain the noncoronary collateral flow from the right atrium as well as that from the venae cavae. Both groups had a sump line in the left ventricle to drain the bronchopulmonary anastomotic blood flow. Results from the study showed that there was no difference between groups in the initial amount of cold cardioplegic solution required to arrest and cool the heart or the initial recording of ventricular temperatures. However, the volume of cardioplegic solution required to maintain the cardiac temperature at less than or equal to 12 degrees C after administration of the initial volume was less (P less than 0.05) for Group 2 than Group 1. Group 2 also had a slower rate of increase in cardiac temperature than Group 1 (P less than 0.01). Results from this study indicate that the constant removal of blood from both cardiac chambers during coronary artery bypass surgery significantly reduces the rate of myocardial rewarming and decreases the amount of cardioplegic solution required to maintain a given cardiac temperature. PMID:3773498

  11. Successful use of levosimendan as a primary inotrope in pediatric cardiac surgery: An observational study in 110 patients

    PubMed Central

    Joshi, Reena Khantwal; Aggarwal, Neeraj; Aggarwal, Mridul; Pandey, Rakesh; Dinand, Veronique; Joshi, Raja

    2016-01-01

    Context: Levosimendan is a new generation inotrope with calcium sensitizing properties and proven benefits in adults. Aims: This study investigates the use of levosimendan as a first line inotrope in congenital heart surgery. Settings and Design: Prospective, observational study in a tertiary care center. Materials and Methods: One hundred and ten patients undergoing congenital cardiac surgery received levosimendan at a loading dose of 12 mcg/kg during rewarming on cardiopulmonary bypass followed by continuous infusion of 0.1 mcg/kg/min for 48 h. Hemodynamic parameters were recorded at the time of admission to Intensive Care Unit, and at 3 h, 6 h, 12 h, 24 h, and 48 h thereafter. Statistical Analysis: Categorical variables were compared using Chi-square test. Non-normally distributed quantitative variables were compared between groups using Kruskal-Wallis test. Results: At discharge from operating room (OR), 36 (32.7%) patients required levosimendan alone to maintain optimum cardiac output, 59 (53.6%) patients required the addition of low-dose adrenaline (<0.1 mcg/kg/min) and 15 (13.6%) patients required either increment in adrenaline to high-dose (≥0.1 mcg/kg/min) or starting another inotrope/vasoactive agent. Overall, there were five mortalities. Hypotension leading to discontinuation of levosimendan was not found in any patient. Arrhythmias were observed in three patients. Fifty-four patients were extubated in the OR. Conclusions: Levosimendan-based inotropic regime offers optimized cardiac output with a well-controlled heart rate and a low incidence of arrhythmias in patients undergoing all categories of congenital heart surgeries. PMID:27011685

  12. Cardiac tumors: leiomyosarcoma - a case report.

    PubMed

    Gierlak, Włodzimierz; Syska-Sumińska, Joanna; Zieliński, Piotr; Dłużniewski, Mirosław; Sadowski, Jerzy

    2015-09-01

    We present a case report of a 60-year-old woman with a long history of leiomyosarcoma in different locations. She was admitted to the clinic due to a left ventricular tumor diagnosed in ECHO examination. The patient was qualified for radical tumor resection. The early postoperative period was complicated due to low cardiac output syndrome and bradyarrhythmia requiring temporary cardiac pacing. Optimized pharmacological therapy resulted in a gradual reduction of symptoms and a clinical improvement of congestive heart failure (NYHA III - NYHA II). Due to the radical nature of the surgery, the patient was not referred for supplementary treatment. The follow-up currently exceeds 12 months - no new metastases have been found. This case provides an example of how to diagnose and treat heart tumors. PMID:26702284

  13. Cardiac tumors: leiomyosarcoma – a case report

    PubMed Central

    Syska-Sumińska, Joanna; Zieliński, Piotr; Dłużniewski, Mirosław; Sadowski, Jerzy

    2015-01-01

    We present a case report of a 60-year-old woman with a long history of leiomyosarcoma in different locations. She was admitted to the clinic due to a left ventricular tumor diagnosed in ECHO examination. The patient was qualified for radical tumor resection. The early postoperative period was complicated due to low cardiac output syndrome and bradyarrhythmia requiring temporary cardiac pacing. Optimized pharmacological therapy resulted in a gradual reduction of symptoms and a clinical improvement of congestive heart failure (NYHA III – NYHA II). Due to the radical nature of the surgery, the patient was not referred for supplementary treatment. The follow-up currently exceeds 12 months – no new metastases have been found. This case provides an example of how to diagnose and treat heart tumors. PMID:26702284

  14. NITROGEN OUTPUTS OF SMALL MAMMALS FROM FECAL AND URINE DEPOSITION: IMPLICATIONS FOR NITROGEN CYCLING

    EPA Science Inventory

    The contribution of small mammals in nitrogen cycling is poorly understood and could have reverberations back to the producer community by maintaining or even magnifying increased nitrogen availability. Our objective was to model nitrogen outputs (deposition of feces and urine) ...

  15. The cardiac hypoxic niche: emerging role of hypoxic microenvironment in cardiac progenitors

    PubMed Central

    Kimura, Wataru

    2012-01-01

    Resident stem cells persist throughout the entire lifetime of an organism where they replenishing damaged cells. Numerous types of resident stem cells are housed in a low-oxygen tension (hypoxic) microenvironment, or niches, which seem to be critical for survival and maintenance of stem cells. Recently our group has identified the adult mammalian epicardium and subepicardium as a hypoxic niche for cardiac progenitor cells. Similar to hematopoietic stem cells (LT-HSCs), progenitor cells in the hypoxic epicardial niche utilize cytoplasmic glycolysis instead of mitochondrial oxidative phosphorylation, where hypoxia inducible factor 1α (Hif-1α) maintains them in glycolytic undifferentiated state. In this review we summarize the relationship between hypoxic signaling and stem cell function, and discuss potential roles of several cardiac stem/progenitor cells in cardiac homeostasis and regeneration. PMID:24282728

  16. NMG documentation, part 3: maintainer`s guide

    SciTech Connect

    Fritsch, F.N.; Dickinson, R.P. Jr.

    1996-07-01

    This is the third of a three-part report documenting NMG, the Numerical Mathematics Guide. Part I is aimed at the user of the systenL It contains an introduction, with an out- line of the complete report, and Chapter 1, User`s Point of View. Part II is aimed at the programmer and contains Chapter 2, How It Works. Part III is aimed at the maintainer of NMG and contains Chapter 3, Maintenance, and Chapter 4, Validation. Because its contents are so specialized, Part III will receive only limited distribution. Note that each chapter has its own page numbering and table of contents.

  17. Numerical simulation of the influence of gravity and posture on cardiac performance

    NASA Technical Reports Server (NTRS)

    Peterson, Kristy; Ozawa, Edwin T.; Pantalos, George M.; Sharp, M. Keith

    2002-01-01

    A numerical model of the cardiovascular system was used to quantify the influences on cardiac function of intrathoracic pressure and intravascular and intraventricular hydrostatic pressure, which are fundamental biomechanical stimuli for orthostatic response. The model included a detailed arterial circulation with lumped parameter models of the atria, ventricles, pulmonary circulation, and venous circulation. The venous circulation was divided into cranial, central, and caudal regions with nonlinear compliance. Changes in intrathoracic pressure and the effects of hydrostatic pressure were simulated in supine, launch, sitting, and standing postures for 0, 1, and 1.8 G. Increasing intrathoracic pressure experienced with increasing gravity caused 12% and 14% decreases in cardiac output for 1 and 1.8 G supine, respectively, compared to 0 G. Similar results were obtained for launch posture, in which the effects of changing intrathoracic pressure dominated those of hydrostatic pressure. Compared to 0 G, cardiac output decreased 0.9% for 1 G launch and 15% for 1.8 G launch. In sitting and standing, the position of the heart above the hydrostatic indifference level caused the effects of changing hydrostatic pressure to dominate those of intrathoracic pressure. Compared to 0 G, cardiac output decreased 13% for 1 G sitting and 23% for 1.8 G sitting, and decreased 17% for 1 G standing and 31% for 1.8 G standing. For a posture change from supine to standing in 1 G, cardiac output decreased, consistent with the trend necessary to explain orthostatic intolerance in some astronauts during postflight stand tests. Simulated lower body negative pressure (LBNP) in 0 G reduced cardiac output and mean aortic pressure similar to I G standing, suggesting that LBNP provides at least some cardiovascular stimuli that may be useful in preventing postflight orthostatic intolerance. A unifying concept, consistent with the Frank-Starling mechanism of the heart, was that cardiac output was proportional to cardiac diastolic transmural pressure for all postures and gravitational accelerations.

  18. Cardiac function of the naked mole-rat: ecophysiological responses to working underground.

    PubMed

    Grimes, Kelly M; Voorhees, Andrew; Chiao, Ying Ann; Han, Hai-Chao; Lindsey, Merry L; Buffenstein, Rochelle

    2014-03-01

    The naked mole-rat (NMR) is a strictly subterranean rodent with a low resting metabolic rate. Nevertheless, it can greatly increase its metabolic activity to meet the high energetic demands associated with digging through compacted soils in its xeric natural habitat where food is patchily distributed. We hypothesized that the NMR heart would naturally have low basal function and exhibit a large cardiac reserve, thereby mirroring the species' low basal metabolism and large metabolic scope. Echocardiography showed that young (2-4 yr old) healthy NMRs have low fractional shortening (28 ± 2%), ejection fraction (43 ± 2%), and cardiac output (6.5 ± 0.4 ml/min), indicating low basal cardiac function. Histology revealed large NMR cardiomyocyte cross-sectional area (216 ± 10 μm(2)) and cardiac collagen deposition of 2.2 ± 0.4%. Neither of these histomorphometric traits was considered pathological, since biaxial tensile testing showed no increase in passive ventricular stiffness. NMR cardiomyocyte fibers showed a low degree of rotation, contributing to the observed low NMR cardiac contractility. Interestingly, when the exercise mimetic dobutamine (3 μg/g ip) was administered, NMRs showed pronounced increases in fractional shortening, ejection fraction, cardiac output, and stroke volume, indicating an increased cardiac reserve. The relatively low basal cardiac function and enhanced cardiac reserve of NMRs are likely to be ecophysiological adaptations to life in an energetically taxing environment. PMID:24363308

  19. Cardiac function of the naked mole-rat: ecophysiological responses to working underground

    PubMed Central

    Grimes, Kelly M.; Voorhees, Andrew; Chiao, Ying Ann; Han, Hai-Chao; Lindsey, Merry L.

    2013-01-01

    The naked mole-rat (NMR) is a strictly subterranean rodent with a low resting metabolic rate. Nevertheless, it can greatly increase its metabolic activity to meet the high energetic demands associated with digging through compacted soils in its xeric natural habitat where food is patchily distributed. We hypothesized that the NMR heart would naturally have low basal function and exhibit a large cardiac reserve, thereby mirroring the species' low basal metabolism and large metabolic scope. Echocardiography showed that young (2–4 yr old) healthy NMRs have low fractional shortening (28 ± 2%), ejection fraction (43 ± 2%), and cardiac output (6.5 ± 0.4 ml/min), indicating low basal cardiac function. Histology revealed large NMR cardiomyocyte cross-sectional area (216 ± 10 μm2) and cardiac collagen deposition of 2.2 ± 0.4%. Neither of these histomorphometric traits was considered pathological, since biaxial tensile testing showed no increase in passive ventricular stiffness. NMR cardiomyocyte fibers showed a low degree of rotation, contributing to the observed low NMR cardiac contractility. Interestingly, when the exercise mimetic dobutamine (3 μg/g ip) was administered, NMRs showed pronounced increases in fractional shortening, ejection fraction, cardiac output, and stroke volume, indicating an increased cardiac reserve. The relatively low basal cardiac function and enhanced cardiac reserve of NMRs are likely to be ecophysiological adaptations to life in an energetically taxing environment. PMID:24363308

  20. Sudden Cardiac Arrest

    MedlinePlus

    ... 9, 2015 Large study reports results comparing two CPR methods used by EMS providers following sudden cardiac ... New England Journal of Medicine , researchers found that cardiopulmonary resuscitation (CPR) administered by emergency medical services (EMS) providers ...

  1. Thyroid hormone regulates cardiac performance during cold acclimation in zebrafish (Danio rerio).

    PubMed

    Little, Alexander G; Seebacher, Frank

    2014-03-01

    Limitations to oxygen transport reduce aerobic scope and thereby activity at thermal extremes. Oxygen transport in fish is facilitated to a large extent by cardiac function so that climate variability may reduce fitness by constraining the performance of the heart. In zebrafish (Danio rerio), thyroid hormone (TH) regulates skeletal muscle function and metabolism in response to thermal acclimation. Here, we aimed to determine whether TH also regulates cardiac function during acclimation. We used propylthiouracil and iopanoic acid to induce hypothyroidism in zebrafish over a 3 week acclimation period to either 18 or 28°C. We found that cold-acclimated fish had higher maximum heart rates and sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA) activity than warm-acclimated fish. Hypothyroid treatment significantly decreased these responses in the cold-acclimated fish, but it did not affect the warm-acclimated fish. TH did not influence SERCA gene transcription, nor did it increase metabolic rate, of isolated whole hearts. To verify that physiological changes following hypothyroid treatment were in fact due to the action of TH, we supplemented hypothyroid fish with 3,5-diiodothryronine (T2) or 3,5,3'-triiodothyronine (T3). Supplementation of hypothyroid fish with T2 or T3 restored heart rate and SERCA activity to control levels. We also show that, in zebrafish, changes in cardiac output in response to warming are primarily mediated by heart rate, rather than by stroke volume. Thus, changes in heart rate are important for the overall aerobic capacity of the fish. In addition to its local effects on heart phenotype, we show that TH increases sympathetic tone on the heart at rest and during maximum exercise. Our findings reveal a new pathway through which fish can mitigate the limiting effects of temperature variability on oxygen transport to maintain aerobic scope and promote thermal tolerance. PMID:24265422

  2. Adaptive Neural Output Feedback Control of Output-Constrained Nonlinear Systems With Unknown Output Nonlinearity.

    PubMed

    Liu, Zhi; Lai, Guanyu; Zhang, Yun; Chen, Chun Lung Philip

    2015-08-01

    This paper addresses the problem of adaptive neural output-feedback control for a class of special nonlinear systems with the hysteretic output mechanism and the unmeasured states. A modified Bouc-Wen model is first employed to capture the output hysteresis phenomenon in the design procedure. For its fusion with the neural networks and the Nussbaum-type function, two key lemmas are established using some extended properties of this model. To avoid the bad system performance caused by the output nonlinearity, a barrier Lyapunov function technique is introduced to guarantee the prescribed constraint of the tracking error. In addition, a robust filtering method is designed to cancel the restriction that all the system states require to be measured. Based on the Lyapunov synthesis, a new neural adaptive controller is constructed to guarantee the prescribed convergence of the tracking error and the semiglobal uniform ultimate boundedness of all the signals in the closed-loop system. Simulations are implemented to evaluate the performance of the proposed neural control algorithm in this paper. PMID:25915964

  3. Cardiac imaging in adults

    SciTech Connect

    Jaffe, C.C.

    1987-01-01

    This book approaches adult cardiac disease from the correlative imaging perspective. It includes chest X-rays and angiographs, 2-dimensional echocardiograms with explanatory diagrams for clarity, plus details on digital radiology, nuclear medicine techniques, CT and MRI. It also covers the normal heart, valvular heart disease, myocardial disease, pericardial disease, bacterial endocarditis, aortic aneurysm, cardiac tumors, and congenital heart disease of the adult. It points out those aspects where one imaging technique has significant superiority.

  4. Autonomic cardiac innervation

    PubMed Central

    Hasan, Wohaib

    2013-01-01

    Autonomic cardiac neurons have a common origin in the neural crest but undergo distinct developmental differentiation as they mature toward their adult phenotype. Progenitor cells respond to repulsive cues during migration, followed by differentiation cues from paracrine sources that promote neurochemistry and differentiation. When autonomic axons start to innervate cardiac tissue, neurotrophic factors from vascular tissue are essential for maintenance of neurons before they reach their targets, upon which target-derived trophic factors take over final maturation, synaptic strength and postnatal survival. Although target-derived neurotrophins have a central role to play in development, alternative sources of neurotrophins may also modulate innervation. Both developing and adult sympathetic neurons express proNGF, and adult parasympathetic cardiac ganglion neurons also synthesize and release NGF. The physiological function of these “non-classical” cardiac sources of neurotrophins remains to be determined, especially in relation to autocrine/paracrine sustenance during development.   Cardiac autonomic nerves are closely spatially associated in cardiac plexuses, ganglia and pacemaker regions and so are sensitive to release of neurotransmitter, neuropeptides and trophic factors from adjacent nerves. As such, in many cardiac pathologies, it is an imbalance within the two arms of the autonomic system that is critical for disease progression. Although this crosstalk between sympathetic and parasympathetic nerves has been well established for adult nerves, it is unclear whether a degree of paracrine regulation occurs across the autonomic limbs during development. Aberrant nerve remodeling is a common occurrence in many adult cardiovascular pathologies, and the mechanisms regulating outgrowth or denervation are disparate. However, autonomic neurons display considerable plasticity in this regard with neurotrophins and inflammatory cytokines having a central regulatory function, including in possible neurotransmitter changes. Certainly, neurotrophins and cytokines regulate transcriptional factors in adult autonomic neurons that have vital differentiation roles in development. Particularly for parasympathetic cardiac ganglion neurons, additional examinations of developmental regulatory mechanisms will potentially aid in understanding attenuated parasympathetic function in a number of conditions, including heart failure. PMID:23872607

  5. UFO - The Universal FEYNRULES Output

    NASA Astrophysics Data System (ADS)

    Degrande, Céline; Duhr, Claude; Fuks, Benjamin; Grellscheid, David; Mattelaer, Olivier; Reiter, Thomas

    2012-06-01

    We present a new model format for automatized matrix-element generators, the so-called Universal FEYNRULES Output (UFO). The format is universal in the sense that it features compatibility with more than one single generator and is designed to be flexible, modular and agnostic of any assumption such as the number of particles or the color and Lorentz structures appearing in the interaction vertices. Unlike other model formats where text files need to be parsed, the information on the model is encoded into a PYTHON module that can easily be linked to other computer codes. We then describe an interface for the MATHEMATICA package FEYNRULES that allows for an automatic output of models in the UFO format.

  6. Microgyroscope with closed loop output

    NASA Technical Reports Server (NTRS)

    Challoner, A. Dorian (Inventor); Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor); Cargille, Donald R. (Inventor)

    2002-01-01

    A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.

  7. Standardized multiple output power supply

    NASA Technical Reports Server (NTRS)

    Ragusa, E. V.

    1975-01-01

    A comprehensive program to develop a prototype model of a standardized multiple output power supply for use in space flight applications is described. The prototype unit was tested and evaluated to assure that the design would provide near optimum performance for the planned application. The prototype design used a dc-to-dc converter incorporating reqenerative current feedback with a time-ratio controlled duty cycle to achieve high efficiency over a wide variation of input voltage and output loads. The packaging concept uses a mainframe capable of accommodating up to four inverter/regulator modules with one common input filter and housekeeping module. Each inverter/regulator module provides a maximum of 100 watts or 10 amperes. Each module is adaptable to operate at any voltage between 4.0 volts and 108 volts. The prototype unit contains +5, + or - 15 and +28 volt modules.

  8. Effects of Lifestyle Modification Programs on Cardiac Risk Factors

    PubMed Central

    Razavi, Moaven; Fournier, Stephen; Shepard, Donald S.; Ritter, Grant; Strickler, Gail K.; Stason, William B.

    2014-01-01

    Medicare conducted a payment demonstration to evaluate the effectiveness of two intensive lifestyle modification programs in patients with symptomatic coronary artery disease: the Dr. Dean Ornish Program for Reversing Heart Disease (Ornish) and Cardiac Wellness Program of the Benson-Henry Mind Body Institute. This report describes the changes in cardiac risk factors achieved by each program during the active intervention year and subsequent year of follow-up. The demonstration enrolled 580 participants who had had an acute myocardial infarction, had undergone coronary artery bypass graft surgery or percutaneous coronary intervention within 12 months, or had documented stable angina pectoris. Of these, 98% completed the intense 3-month intervention, 71% the 12-month intervention, and 56% an additional follow-up year. Most cardiac risk factors improved significantly during the intense intervention period in both programs. Favorable changes in cardiac risk factors and functional cardiac capacity were maintained or improved further at 12 and 24 months in participants with active follow-up. Multivariable regressions found that risk-factor improvements were positively associated with abnormal baseline values, Ornish program participation for body mass index and systolic blood pressure, and with coronary artery bypass graft surgery. Expressed levels of motivation to lose weight and maintain weight loss were significant independent predictors of sustained weight loss (p = 0.006). Both lifestyle modification programs achieved well-sustained reductions in cardiac risk factors. PMID:25490202

  9. Effects of lifestyle modification programs on cardiac risk factors.

    PubMed

    Razavi, Moaven; Fournier, Stephen; Shepard, Donald S; Ritter, Grant; Strickler, Gail K; Stason, William B

    2014-01-01

    Medicare conducted a payment demonstration to evaluate the effectiveness of two intensive lifestyle modification programs in patients with symptomatic coronary artery disease: the Dr. Dean Ornish Program for Reversing Heart Disease (Ornish) and Cardiac Wellness Program of the Benson-Henry Mind Body Institute. This report describes the changes in cardiac risk factors achieved by each program during the active intervention year and subsequent year of follow-up. The demonstration enrolled 580 participants who had had an acute myocardial infarction, had undergone coronary artery bypass graft surgery or percutaneous coronary intervention within 12 months, or had documented stable angina pectoris. Of these, 98% completed the intense 3-month intervention, 71% the 12-month intervention, and 56% an additional follow-up year. Most cardiac risk factors improved significantly during the intense intervention period in both programs. Favorable changes in cardiac risk factors and functional cardiac capacity were maintained or improved further at 12 and 24 months in participants with active follow-up. Multivariable regressions found that risk-factor improvements were positively associated with abnormal baseline values, Ornish program participation for body mass index and systolic blood pressure, and with coronary artery bypass graft surgery. Expressed levels of motivation to lose weight and maintain weight loss were significant independent predictors of sustained weight loss (p = 0.006). Both lifestyle modification programs achieved well-sustained reductions in cardiac risk factors. PMID:25490202

  10. Cardiac Applications for Human Pluripotent Stem Cells

    PubMed Central

    Shiba, Yuji; Hauch, Kip D.; Laflamme, Michael A.

    2010-01-01

    Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) can self-renew indefinitely, while maintaining the capacity to differentiate into useful somatic cell types, including cardiomyocytes. As such, these stem cell types represent an essentially inexhaustible source of committed human cardiomyocytes of potential use in cell-based cardiac therapies, high-throughput screening and safety testing of new drugs, and modeling human heart development. These stem cell-derived cardiomyocytes have an unambiguous cardiac phenotype and proliferate robustly both in vitro and in vivo. Recent transplantation studies in preclinical models have provided exciting proof-of-principle for their use in infarct repair and in the formation of a “biological pacemaker”. While these successes give reason for cautious optimism, major challenges remain to the successful application of hESCs (or hiPSCs) to cardiac repair, including the need for preparations of high cardiac purity, improved methods of delivery, and approaches to overcome immune rejection and other causes of graft cell death. In this review, we describe the phenotype of hESC- and hiPSC-derived cardiomyocytes, the state of preclinical transplantation studies with these cells, and potential approaches to overcome the aforementioned hurdles. PMID:19689350

  11. Direct Cardiac Reprogramming: Advances in Cardiac Regeneration

    PubMed Central

    Chen, Olivia; Qian, Li

    2015-01-01

    Heart disease is one of the lead causes of death worldwide. Many forms of heart disease, including myocardial infarction and pressure-loading cardiomyopathies, result in irreversible cardiomyocyte death. Activated fibroblasts respond to cardiac injury by forming scar tissue, but ultimately this response fails to restore cardiac function. Unfortunately, the human heart has little regenerative ability and long-term outcomes following acute coronary events often include chronic and end-stage heart failure. Building upon years of research aimed at restoring functional cardiomyocytes, recent advances have been made in the direct reprogramming of fibroblasts toward a cardiomyocyte cell fate both in vitro and in vivo. Several experiments show functional improvements in mouse models of myocardial infarction following in situ generation of cardiomyocyte-like cells from endogenous fibroblasts. Though many of these studies are in an early stage, this nascent technology holds promise for future applications in regenerative medicine. In this review, we discuss the history, progress, methods, challenges, and future directions of direct cardiac reprogramming. PMID:26176012

  12. Net cardiac shunts in anuran amphibians: physiology or physics?

    PubMed

    Hillman, Stanley S; Hedrick, Michael S; Kohl, Zachary F

    2014-08-15

    Amphibians have a single ventricle and common conus arteriosus that produces an equal pressure to the parallel pulmocutaneous and systemic vascular circuits. The distribution of blood flows between the pulmocutaneous (Qpul) and systemic (Qsys) circuits (net cardiac shunt) varies with a number of environmental conditions and behaviours; although autonomic regulation of pulmonary vascular resistance conductance has been emphasized, little attention has been paid to the possible contribution of the passive physical characteristics of the two circuits to pressure changes associated with variation in cardiac output. In this study, we re-analysed three recent studies that recorded net cardiac shunts in the cane toad (Rhinella marina) under a variety of conditions and treatments. In all three studies, Qpul and Qsys were linearly related to cardiac output (Qtot), but the slope was threefold higher for Qpul compared with Qsys as predicted by relative conductance increases associated with increases in pressure from perfused preparations where autonomic regulation and humoral control were eliminated. Our analysis indicates that the net cardiac shunt in the cane toad is predicted primarily by the physical, rather than physiological, characteristics of the parallel pulmonary and systemic vascular circuits. PMID:24902743

  13. Maintaining consistency in distributed systems

    NASA Technical Reports Server (NTRS)

    Birman, Kenneth P.

    1991-01-01

    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  14. CARMEN, a human super enhancer-associated long noncoding RNA controlling cardiac specification, differentiation and homeostasis.

    PubMed

    Ounzain, Samir; Micheletti, Rudi; Arnan, Carme; Plaisance, Isabelle; Cecchi, Dario; Schroen, Blanche; Reverter, Ferran; Alexanian, Michael; Gonzales, Christine; Ng, Shi Yan; Bussotti, Giovanni; Pezzuto, Iole; Notredame, Cedric; Heymans, Stephane; Guigó, Roderic; Johnson, Rory; Pedrazzini, Thierry

    2015-12-01

    Long noncoding RNAs (lncRNAs) are emerging as important regulators of developmental pathways. However, their roles in human cardiac precursor cell (CPC) remain unexplored. To characterize the long noncoding transcriptome during human CPC cardiac differentiation, we profiled the lncRNA transcriptome in CPCs isolated from the human fetal heart and identified 570 lncRNAs that were modulated during cardiac differentiation. Many of these were associated with active cardiac enhancer and super enhancers (SE) with their expression being correlated with proximal cardiac genes. One of the most upregulated lncRNAs was a SE-associated lncRNA that was named CARMEN, (CAR)diac (M)esoderm (E)nhancer-associated (N)oncoding RNA. CARMEN exhibits RNA-dependent enhancing activity and is upstream of the cardiac mesoderm-specifying gene regulatory network. Interestingly, CARMEN interacts with SUZ12 and EZH2, two components of the polycomb repressive complex 2 (PRC2). We demonstrate that CARMEN knockdown inhibits cardiac specification and differentiation in cardiac precursor cells independently of MIR-143 and -145 expression, two microRNAs located proximal to the enhancer sequences. Importantly, CARMEN expression was activated during pathological remodeling in the mouse and human hearts, and was necessary for maintaining cardiac identity in differentiated cardiomyocytes. This study demonstrates therefore that CARMEN is a crucial regulator of cardiac cell differentiation and homeostasis. PMID:26423156

  15. Random output and hospital performance.

    PubMed

    Barros, Pedro Pita

    2003-11-01

    Many countries are under pressure to reform health care financing and delivery. Hospital care is one part of the health system that is under scrutiny. Private management initiatives are a possible way to increase efficiency in health care delivery. This motivates the interest in developing methodologies to assess hospital performance, recognizing hospitals as a different sort of firm. We present a simple way to describe hospital production: hospital output as a change in the distribution of survival probabilities. This output definition allows us to separate hospital production from patients' characteristics. The notion of "better performance" has a precise meaning: (first-order) stochastic dominance of a distribution of survival probabilities over another distribution. As an illustration, we compare, for an important DRG, private and public management and find that private management performs better, mainly in the range of high-survival probabilities. The measured performance difference cannot be attributed to input prices or to economies of scale and/or scope. It reflects pure technological and organisational differences. PMID:14686628

  16. Engineered cardiac tissues

    PubMed Central

    Iyer, Rohin K.; Chiu, Loraine L. Y.; Reis, Lewis A.; Radisic, Milica

    2011-01-01

    Cardiac tissue engineering offers the promise of creating functional tissue replacements for use in the failing heart or for in vitro drug screening. The last decade has seen a great deal of progress in this field with new advances in interdisciplinary areas such as developmental biology, genetic engineering, biomaterials, polymer science, bioreactor engineering, and stem cell biology. We review here a selection of the most recent advances in cardiac tissue engineering, including the classical cell-scaffold approaches, advanced bioreactor designs, cell sheet engineering, whole organ decellularization, stem-cell based approaches, and topographical control of tissue organization and function. We also discuss current challenges in the field, such as maturation of stem cell-derived cardiac patches and vascularization. PMID:21530228

  17. Malignant primary cardiac tumours

    PubMed Central

    Burnside, Nathan; MacGowan, Simon W.

    2012-01-01

    OBJECTIVES Management of malignant tumours of the heart remains a poorly investigated clinical area due to the scarcity of presentations. The purpose of this series and review is to present an outline of the management emphasized by our personal experience in a regional cardiothoracic centre. METHODS We reviewed all cases presenting with primary cardiac tumours in our institution within the last 10 years, looking at presentation, management and outcomes. RESULTS Of these, the records of 3 patients, who attended the Royal Victoria Hospital in Belfast and were treated for a cardiac sarcoma, were fully evaluated. A review of current literature was conducted through a search of Pubmed and Medline databases. A review of the presentation of these patients and the generally accepted management deterioration of patients diagnosed with cardiac sarcoma is discussed. CONCLUSIONS With reference to our case series, we want to draw attention to the rapid deteriation of these patients following presentation. PMID:22922450

  18. Primary cardiac tumors.

    PubMed Central

    Silverman, N A

    1980-01-01

    Cardiac tumors are a rare, but potentially curably form of heart disease. A high index of clinical suspicion is necessary for diagnosis as these tumors have protean manifestations that mimic a variety of other cardiac and noncardiac diseases. Presently, M-mode and two-dimensional echocardiography are utilized as safe, reliable, and noninvasive imaging modalities. Seventy-five per cent of these tumors are benign, with myxoma accounting for 50% and rhabodomyoma comprising 20% of lesions. Various histologic types of sarcoma are the predominant malignant cardiac neoplasms. With strict attention to avoiding perioperative tumor embolization, surgical resection of these lesions can be accomplished with minimal morbidity and mortality. Sixteen consecutive primary tumors of the heart have been surgically treated at Duke University Medical Center since 1966 with no perioperative deaths and no late recurrences. Images Figs. 2A and B. Fig. 3. Fig. 4. Figs. 5A and B Fig. 6. PMID:7362282

  19. Influence of gravity on cardiac performance

    NASA Technical Reports Server (NTRS)

    Pantalos, G. M.; Sharp, M. K.; Woodruff, S. J.; O'Leary, D. S.; Lorange, R.; Everett, S. D.; Bennett, T. E.; Shurfranz, T.

    1998-01-01

    Results obtained by the investigators in ground-based experiments and in two parabolic flight series of tests aboard the NASA KC-135 aircraft with a hydraulic simulator of the human systemic circulation have confirmed that a simple lack of hydrostatic pressure within an artificial ventricle causes a decrease in stroke volume of 20%-50%. A corresponding drop in stroke volume (SV) and cardiac output (CO) was observed over a range of atrial pressures (AP), representing a rightward shift of the classic CO versus AP cardiac function curve. These results are in agreement with echocardiographic experiments performed on space shuttle flights, where an average decrease in SV of 15% was measured following a three-day period of adaptation to weightlessness. The similarity of behavior of the hydraulic model to the human system suggests that the simple physical effects of the lack of hydrostatic pressure may be an important mechanism for the observed changes in cardiac performance in astronauts during the weightlessness of space flight.

  20. THE ARTIFICIAL CARDIAC PACEMAKER. INDICATIONS FOR IMPLANTATION.

    PubMed

    ROE, B B; BRUNS, D L

    1964-12-01

    Extensive clinical experience has demonstrated that implantable cardiac pacemakers are safe and effective mechanisms for controlling symptoms and preventing the hazards of third degree heart block with Stokes-Adams syncope. Medical management of this disease does not provide reliable protection and life expectancy averages about two years after diagnosis. Hence the negligible surgical morbidity and mortality associated with pacemaker implantation justifies broad indications to implant one of the four commercially available battery-powered units. ELECTIVE IMPLANTATION OF A PACEMAKER SHOULD BE CONSIDERED IN PATIENTS WITH PERSISTENT THIRD DEGREE HEART BLOCK WHO HAVE HAD: One or more episodes of Stokes-Adams syncope; surgical injury to the conduction system, regardless of syncopal attacks; evidence of low cardiac output with cardiomegaly secondary to bradycardia. Few if any other cardiac arrythmias are satisfactorily controlled by an electrical pacemaker. Emergency pacemaker control is obviously necessary for patients developing intractable or recurrent bouts of asystole. During the interval until an implantable unit can be obtained and sterilized, the patient may be controlled by intravenous isoproterenol or by an external pacemaker attached to a transvenous catheter electrode, a precordial skin electrode or a percutaneous myocardial wire electrode. PMID:14236028

  1. Antibodies to cardiac receptors.

    PubMed

    Boivin-Jahns, V; Schlipp, A; Hartmann, S; Panjwani, P; Klingel, K; Lohse, M J; Ertl, G; Jahns, R

    2012-12-01

    Inflammation of cardiac tissue is generally associated with an activation of the host's immune system. On the one hand, this activation is mandatory to protect the heart by fighting the invading microbial agents or toxins and by engaging myocardial reparation and healing processes. On the other hand, uncontrolled activation of the immune defense has the risk of an arousal of auto- or cross-reactive immune cells, which in some cases bring more harm than good. Dependent on the individual genetic predisposition, such heart-directed autoimmune reactions most likely occur as a result of myocyte apoptosis or necrosis and subsequent liberation of self-antigens previously hidden to the immune system. During the past two decades, evidence for a pathogenic relevance of autoimmunity in human heart disease has substantially increased. Conformational cardiac (auto)antibodies affecting cardiac function and, in particular, (auto)antibodies that target G protein-coupled cardiac membrane receptors are thought to play a key role in the development of heart failure. Clinical pilot studies even suggest that such antibodies negatively affect survival in heart failure patients. However, the true prevalence and clinical impact of many cardiac (auto)antibodies in human heart diseases are still unclear, as are the events triggering their formation, their titer course, and their patterns of clearance and/or persistence. The present article summarizes current knowledge in the field of cardiac receptor (auto)antibodies including recent efforts to address some of the aforementioned gaps of knowledge, thereby attempting to pave the way for novel, more specific therapeutic approaches. PMID:23183584

  2. Remotely maintained waste transfer pump

    SciTech Connect

    Eargle, J.C.

    1990-01-01

    Westinghouse Savannah River Company (WSRC) operates the Savannah River Site (SRS) for the Department of Energy (DOE). Waste from the processing of irradiated material is stored in large shielded tanks. Treated liquid wastes are to be transferred from these tanks to the Defense Waste Processing Facility (DWPF) for incorporation in glass suitable for storage in a federal repository. Characteristics of the wastes range from water-like liquid to highly viscous wastes containing suspended solids. Pumping head requirements for various conditions ranged from 10 meters (35 feet) to 168 meters (550 feet). A specially designed, cantilever type, remotely operated and maintained pump was designed and built to transfer the wastes. To demonstrate the design, a prototype pump was built and testing thoroughly with simulated waste. Severe vibration problems were overcome by proper drive shaft selection and careful control of the space between the pump shaft and fixed running clearances (sometimes called seals). Eleven pumps are now installed and six pumps have been successfully run in water service.

  3. Remotely maintained waste transfer pump

    SciTech Connect

    Eargle, J.C.

    1990-12-31

    Westinghouse Savannah River Company (WSRC) operates the Savannah River Site (SRS) for the Department of Energy (DOE). Waste from the processing of irradiated material is stored in large shielded tanks. Treated liquid wastes are to be transferred from these tanks to the Defense Waste Processing Facility (DWPF) for incorporation in glass suitable for storage in a federal repository. Characteristics of the wastes range from water-like liquid to highly viscous wastes containing suspended solids. Pumping head requirements for various conditions ranged from 10 meters (35 feet) to 168 meters (550 feet). A specially designed, cantilever type, remotely operated and maintained pump was designed and built to transfer the wastes. To demonstrate the design, a prototype pump was built and testing thoroughly with simulated waste. Severe vibration problems were overcome by proper drive shaft selection and careful control of the space between the pump shaft and fixed running clearances (sometimes called seals). Eleven pumps are now installed and six pumps have been successfully run in water service.

  4. 10 CFR 26.71 - Maintaining authorization.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Maintaining authorization. 26.71 Section 26.71 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Granting and Maintaining Authorization § 26.71 Maintaining authorization. (a) Individuals may maintain authorization under the following conditions: (1)...

  5. 10 CFR 26.71 - Maintaining authorization.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Maintaining authorization. 26.71 Section 26.71 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Granting and Maintaining Authorization § 26.71 Maintaining authorization. (a) Individuals may maintain authorization under the following conditions: (1)...

  6. 10 CFR 26.71 - Maintaining authorization.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Maintaining authorization. 26.71 Section 26.71 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Granting and Maintaining Authorization § 26.71 Maintaining authorization. (a) Individuals may maintain authorization under the following conditions: (1)...

  7. 10 CFR 26.71 - Maintaining authorization.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Maintaining authorization. 26.71 Section 26.71 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Granting and Maintaining Authorization § 26.71 Maintaining authorization. (a) Individuals may maintain authorization under the following conditions: (1)...

  8. 10 CFR 26.71 - Maintaining authorization.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Maintaining authorization. 26.71 Section 26.71 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Granting and Maintaining Authorization § 26.71 Maintaining authorization. (a) Individuals may maintain authorization under the following conditions: (1)...

  9. Determinants of water and sodium intake and output.

    PubMed

    Stanhewicz, Anna E; Kenney, W Larry

    2015-09-01

    Physiological regulation of sodium and water intake and output is required for the maintenance of homeostasis. The behavioral and neuroendocrine mechanisms that govern fluid and salt balance are highly interdependent, with acute and chronic alterations in renal output tightly balanced by appropriate changes in thirst and, to a lesser extent in humans, sodium appetite. In healthy individuals, these tightly coupled mechanisms maintain extracellular fluid volume and body tonicity within a narrow homeostatic range by initiating ingestive behaviors and the release of hormones necessary to conserve water and sodium within the body. In this review, the factors that determine output of sodium and fluid and those that determine "normal" input (i.e., matched to output) are addressed. For output, individual variability accompanied by dysregulation of homeostatic mechanisms may contribute to acute and/or chronic disease. To illustrate that point, the specific condition of salt-sensitive hypertension is discussed. For input, physical characteristics, physiological phenotypes, genetic and developmental influences, and cultural and environmental factors combine to result in a wide range of individual variability that, in humans, is compensated for by alterations in excretion. PMID:26290293

  10. A New Frontier for Cardiac Monitoring

    NASA Technical Reports Server (NTRS)

    2001-01-01

    CardioDynamics International Corporation (CDIC) has created the BioZ(TM) System through a Small Business Innovation Research (SBIR) award from Johnson Space Center, providing patients and physicians with a cost-effective and highly accurate monitoring system.The BioZ non-invasive heart monitor is based on a technology known as Impedance Cardiography (ICG). BioZ provides the physician with vital information about the heart's ability to deliver blood to the body, the force one's heart exerts with each beat, and the amount of fluid in the chest. Specially designed bioimpedance sensors placed on the neck and chest monitor 12 different parameters, including cardiac output, contractility, systemic vascular resistance, and thoracic fluid content. These sensors monitor the electrical conductivity of the body-information that is converted into blood flow data and is displayed in real time on a monitoring screen. BioZ.com(TM) and BioZ.pc(TM) are two additional products that incorporate the same sensors present in the original BioZ system. The "com" in BioZ.com stands for cardiac output monitor. This fully integrated system is essentially a smaller version of the BioZ, combining the same abilities with a compact, lightweight design, while providing greater portability.

  11. Mechanisms of cardiac arrhythmias

    PubMed Central

    Tse, Gary

    2015-01-01

    Blood circulation is the result of the beating of the heart, which provides the mechanical force to pump oxygenated blood to, and deoxygenated blood away from, the peripheral tissues. This depends critically on the preceding electrical activation. Disruptions in the orderly pattern of this propagating cardiac excitation wave can lead to arrhythmias. Understanding of the mechanisms underlying their generation and maintenance requires knowledge of the ionic contributions to the cardiac action potential, which is discussed in the first part of this review. A brief outline of the different classification systems for arrhythmogenesis is then provided, followed by a detailed discussion for each mechanism in turn, highlighting recent advances in this area. PMID:27092186

  12. Cardiac heat production.

    PubMed

    Gibbs, C L; Chapman, J B

    1979-01-01

    The energy production (heat + work) of cardiac muscle must be interpreted in terms of the major ATPases underwriting cardiac contraction; these are the Ca2+ and Na+-K+ transport ATPases and actomyosin ATPase. It is possible to apply the classical phenomenological subdivisions to cardiac energy production; when this is done, certain properties immediately distinguish cardiac muscle from skeletal muscle. Little or no temporal distinction exists between initial (anaerobic) and recovery (oxidative) metabolism. Even at temperatures as low as 20 degrees C most of the recovery heat is released within the time course of a single contraction. Cardiac muscle is characterized by a high resting heat rate, the magnitude of which varies between species and depends on the metabolic substrate. In isometric contractions there is a slightly curvilinear relationship between developed force and heat production. There is a tension-independent or activation component, the magnitude of which reflects the prevailing level of contractility and is probably associated with calcium release and retrieval. In isotonic contractions energy production is maximal when the muscle is heavily loaded but falls steeply when the size of the load is reduced. The enthalpy:load relation is probably similar to that found in twitch contractions of skeletal muscle working at room temperature or above; but, unlike for skeletal muscle, there are families of such curves: At any instant of time the relation depends upon the prevailing physiological conditions (e.g. stimulus rate, substrate supply, humoral agents, extracellular ionic concentrations, initial length). Cardiac energy production can be estimated by a variety of other techniques (such as high-energy phosphate utilization, oxygen consumption, and changes in tissue fluorescence related to pyridine nucleotide oxidation levels). At the present time there is considerable agreement between heat measurements and results obtained with these different techniques. We should like to conclude on a cautionary note. First, there is considerable variability in the properties of cardiac muscle from different species. Significant variations occur at nearly all levels of cellular function--e.g. shape of action potential, electrical and mechanical dependence upon stimulus history, mechanisms of excitation-contraction coupling, actomyosin ATPase activity, metabolic regulation, and differential sensitivity to anoxia or ischemia. Second, the types of contractions readily studied in isolated papillary muscles (i.e. isometric or isotonic twitches) may not necessarily be the best mechanical paradigms for understanding myocardial energetics in vivo. The particular geometric demands of individual research techniques require the use of a wide variety of myocardial preparations from a wide variety of species. This necessarily produces a pastiche view of cardiac muscle rather than an integrated picture of some hypothetically typical mammalian myocardium. PMID:219764

  13. Comparative Analysis of Telomerase Activity in CD117+CD34+ Cardiac Telocytes with Bone Mesenchymal Stem Cells, Cardiac Fibroblasts and Cardiomyocytes

    PubMed Central

    Li, Yuan-Yuan; Lu, Shan-Shan; Xu, Ting; Zhang, Hong-Qi; Li, Hua

    2015-01-01

    Background: This study characterized the cardiac telocyte (TC) population both in vivo and in vitro, and investigated its telomerase activity related to mitosis. Methods: Using transmission electron microscopy and a phase contrast microscope, the typical morphological features of cardiac TCs were observed; by targeting the cell surface proteins CD117 and CD34, CD117+CD34+ cardiac TCs were sorted via flow cytometry and validated by immunofluorescence based on the primary cell culture. Then the optimized basal nutrient medium for selected population was examined with the cell counting kit 8. Under this conditioned medium, the process of cell division was captured, and the telomerase activity of CD117+CD34+ cardiac TCs was detected in comparison with bone mesenchymal stem cells (BMSCs), cardiac fibroblasts (CFBs), cardiomyocytes (CMs). Results: Cardiac TCs projected characteristic telopodes with thin segments (podomers) in alternation with dilation (podoms). In addition, 64% of the primary cultured cardiac TCs were composed of CD117+CD34+ cardiac TCs; which was verified by immunofluorescence. In a live cell imaging system, CD117+CD34+ cardiac TCs were observed to enter into cell division in a short time, followed by an significant invagination forming across the middle of the cell body. Using a real-time quantitative telomeric-repeat amplification assay, the telomerase concentration in CD117+CD34+ cardiac TCs was obviously lower than in BMSCs and CFBs, and significantly higher than in CMs. Conclusions: Cardiac TCs represent a unique cell population and CD117+CD34+ cardiac TCs have relative low telomerase activity that differs from BMSCs, CFBs and CMs and thus they might play an important role in maintaining cardiac homeostasis. PMID:26168836

  14. Cardiac Response and Personality Organization

    ERIC Educational Resources Information Center

    Blatt, Sidney J.; Feirstein, Alan

    1977-01-01

    This study examines the level and variability of cardiac response during complex problem-solving and interposed rest periods and their differing relationships to estimates of personality integration on the Rorschach. Findings suggest cardiac variability may be a more differentiated measure than level of cardiac response. (Author)

  15. Enemies maintain hyperdiverse tropical forests.

    PubMed

    Terborgh, John

    2012-03-01

    Understanding tropical forest tree diversity has been a major challenge to ecologists. In the absence of compensatory mechanisms, two powerful forces, drift and competition, are expected to erode diversity quickly, especially in communities containing scores or hundreds of rare species. Here, I review evidence bearing on four compensatory mechanisms that have been subsumed under the terms "density dependence" or "negative density dependence": (1) intra- and (2) interspecific competition and the action of (3) density-responsive and (4) distance-responsive biotic agents, as postulated by Janzen and Connell. To achieve ontological integration, I examine evidence based on studies employing seeds, seedlings, and saplings. Available evidence points overwhelmingly to the action of both host-generalist and host-restricted biotic agents as causing most seed and seedling mortality, implying that species diversity is maintained via top-down forcing. The overall effect of most host-generalist seed predators and herbivores is to even out the distribution of surviving propagules. Spatially restricted recruitment appears to result mainly, if not exclusively, from the actions of host-restricted agents, principally microarthropods and fungi, that attack hosts in a distance-dependent fashion as Janzen and Connell proposed. Near total failure of propagules close to reproductive conspecifics ensures that successful reproduction occurs through a scant rain of dispersed seeds. Densities of dispersed seeds and seedlings arising from them are so low as to generally preclude the operation of density dependence, at least during early ontogenetic stages. I conclude that Janzen and Connell were essentially correct and that diversity maintenance results from top-down forcing acting in a spatially nonuniform fashion. PMID:22322219

  16. Digital plus analog output encoder

    NASA Technical Reports Server (NTRS)

    Hafle, R. S. (Inventor)

    1976-01-01

    The disclosed encoder is adapted to produce both digital and analog output signals corresponding to the angular position of a rotary shaft, or the position of any other movable member. The digital signals comprise a series of binary signals constituting a multidigit code word which defines the angular position of the shaft with a degree of resolution which depends upon the number of digits in the code word. The basic binary signals are produced by photocells actuated by a series of binary tracks on a code disc or member. The analog signals are in the form of a series of ramp signals which are related in length to the least significant bit of the digital code word. The analog signals are derived from sine and cosine tracks on the code disc.

  17. Lineage Reprogramming of Fibroblasts into Proliferative Induced Cardiac Progenitor Cells by Defined Factors.

    PubMed

    Lalit, Pratik A; Salick, Max R; Nelson, Daryl O; Squirrell, Jayne M; Shafer, Christina M; Patel, Neel G; Saeed, Imaan; Schmuck, Eric G; Markandeya, Yogananda S; Wong, Rachel; Lea, Martin R; Eliceiri, Kevin W; Hacker, Timothy A; Crone, Wendy C; Kyba, Michael; Garry, Daniel J; Stewart, Ron; Thomson, James A; Downs, Karen M; Lyons, Gary E; Kamp, Timothy J

    2016-03-01

    Several studies have reported reprogramming of fibroblasts into induced cardiomyocytes; however, reprogramming into proliferative induced cardiac progenitor cells (iCPCs) remains to be accomplished. Here we report that a combination of 11 or 5 cardiac factors along with canonical Wnt and JAK/STAT signaling reprogrammed adult mouse cardiac, lung, and tail tip fibroblasts into iCPCs. The iCPCs were cardiac mesoderm-restricted progenitors that could be expanded extensively while maintaining multipotency to differentiate into cardiomyocytes, smooth muscle cells, and endothelial cells in vitro. Moreover, iCPCs injected into the cardiac crescent of mouse embryos differentiated into cardiomyocytes. iCPCs transplanted into the post-myocardial infarction mouse heart improved survival and differentiated into cardiomyocytes, smooth muscle cells, and endothelial cells. Lineage reprogramming of adult somatic cells into iCPCs provides a scalable cell source for drug discovery, disease modeling, and cardiac regenerative therapy. PMID:26877223

  18. Nonexercise cardiac stress testing

    SciTech Connect

    Vacek, J.L.; Baldwin, T. )

    1989-09-15

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

  19. [Insertable Cardiac Monitor].

    PubMed

    Lewalter, Thorsten; Koutsouraki, Ilia; Brodherr, Turgut

    2015-08-01

    Intermittent cardiac arrhythmias are sometimes difficult to register using conventional detection concepts. The implantable event recorders offer a unique opportunity to document short lasting or rare and even asymptomatic arrhythmias. This manuscript describes event recorder implantation in a step-by-step manner. PMID:26306017

  20. Hepato-cardiac disorders

    PubMed Central

    Fouad, Yasser Mahrous; Yehia, Reem

    2014-01-01

    Understanding the mutual relationship between the liver and the heart is important for both hepatologists and cardiologists. Hepato-cardiac diseases can be classified into heart diseases affecting the liver, liver diseases affecting the heart, and conditions affecting the heart and the liver at the same time. Differential diagnoses of liver injury are extremely important in a cardiologist’s clinical practice calling for collaboration between cardiologists and hepatologists due to the many other diseases that can affect the liver and mimic haemodynamic injury. Acute and chronic heart failure may lead to acute ischemic hepatitis or chronic congestive hepatopathy. Treatment in these cases should be directed to the primary heart disease. In patients with advanced liver disease, cirrhotic cardiomyopathy may develop including hemodynamic changes, diastolic and systolic dysfunctions, reduced cardiac performance and electrophysiological abnormalities. Cardiac evaluation is important for patients with liver diseases especially before and after liver transplantation. Liver transplantation may lead to the improvement of all cardiac changes and the reversal of cirrhotic cardiomyopathy. There are systemic diseases that may affect both the liver and the heart concomitantly including congenital, metabolic and inflammatory diseases as well as alcoholism. This review highlights these hepatocardiac diseases PMID:24653793

  1. Cardiac Physiology of Pregnancy.

    PubMed

    May, Linda

    2015-07-01

    Although the physiology of the heart and vascular system has not changed, there are many things we have learned and are still learning today. Research related to heart adaptations during pregnancy has been performed since the 1930s. Since the mid-1950s, researchers began to look at changes in the maternal cardiovascular system during exercise while pregnant. Research related to exercise during pregnancy and offspring heart development began and has continued since the 1970s. We will review the normal female cardiovascular system adaptations to pregnancy in general. Additionally, topics related to maternal cardiac adaptations to pregnancy during acute exercise, as well as the chronic conditioning response from exercise training will be explored. Since physical activity during pregnancy influences fetal development, the fetal cardiac development will be discussed in regards to acute and chronic maternal exercise. Similarly, the influence of various types of maternal exercise on acute and chronic fetal heart responses will be described. Briefly, the topics related to how and if there is maternal-fetal synchrony will be explained. Lastly, the developmental changes of the fetal cardiovascular system that persist after birth will be explored. Overall, the article will discuss maternal cardiac physiology related to changes with normal pregnancy, and exercise during pregnancy, as well as fetal cardiac physiology related to changes with normal development, and exercise during pregnancy as well as developmental changes in offspring after birth. PMID:26140720

  2. Digital cardiac imaging

    SciTech Connect

    Buda, A.J.; Delp, E.J.

    1985-01-01

    This book contains 16 papers. Some of the titles are: The analysis of left ventricular function with digital subtraction angiography; Digital radiographic assessment of coronary flow reserve; Clinical application of cardiac CT; Digital two-dimensional echocardiography; and Magnetic resonance imaging of the heart.

  3. Comparative cardiac imaging

    SciTech Connect

    Brundage, B.H.

    1990-01-01

    This book is designed to compare all major cardiac imaging techniques. All major imaging techniques - including conventional angiography, digital angiography, echocardiography and Doppler imaging, conventional radioisotope techniques, computed tomography, and magnetic resonance imaging - are covered in this text as they apply to the major cardiovascular disorders. There is brief coverage of positron emission tomography and an extensive presentation of ultrafast computed tomography.

  4. Advanced Cardiac Life Support.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document contains materials for an advanced college course in cardiac life support developed for the State of Iowa. The course syllabus lists the course title, hours, number, description, prerequisites, learning activities, instructional units, required text, six references, evaluation criteria, course objectives by units, course…

  5. Moore's law, Dabbawalas, and pediatric cardiac care in Sri Lanka

    PubMed Central

    Samarasinghe, Duminda

    2015-01-01

    Sri Lanka is an island nation in Indian Ocean that provides free healthcare to all citizens through government healthcare system. It has commendable health indices in the region. Pediatric cardiac services have rapidly progressed over past few years helping to further bring down infant and under-five mortality rates. Lady Ridgeway Hospital for Children (LRH) is the only tertiary care referral center for children with heart disease in the country. Currently it performs approximately 1,000 cardiac catheterizations and 1,000 cardiac surgeries every year. Target is to double the surgical output to treat all children with heart diseases in a timely and appropriate manner. Being a middle-income country, this is not an easy task. Technology used in diagnosis and treatment of congenital heart diseases is rapidly advancing with its price tag. In such a setting, it is challenging to proceed to achieve this target in a resource-limited environment. PMID:26085764

  6. Biventricular Pacing (Cardiac Resynchronization Therapy)

    PubMed Central

    2005-01-01

    Executive Summary Issue In 2002, (before the establishment of the Ontario Health Technology Advisory Committee), the Medical Advisory Secretariat conducted a health technology policy assessment on biventricular (BiV) pacing, also called cardiac resynchronization therapy (CRT). The goal of treatment with BiV pacing is to improve cardiac output for people in heart failure (HF) with conduction defect on ECG (wide QRS interval) by synchronizing ventricular contraction. The Medical Advisory Secretariat concluded that there was evidence of short (6 months) and longer-term (12 months) effectiveness in terms of cardiac function and quality of life (QoL). More recently, a hospital submitted an application to the Ontario Health Technology Advisory Committee to review CRT, and the Medical Advisory Secretariat subsequently updated its health technology assessment. Background Chronic HF results from any structural or functional cardiac disorder that impairs the ability of the heart to act as a pump. It is estimated that 1% to 5% of the general population (all ages) in Europe have chronic HF. (1;2) About one-half of the patients with HF are women, and about 40% of men and 60% of women with this condition are aged older than 75 years. The incidence (i.e., the number of new cases in a specified period) of chronic HF is age dependent: from 1 to 5 per 1,000 people each year in the total population, to as high as 30 to 40 per 1,000 people each year in those aged 75 years and older. Hence, in an aging society, the prevalence (i.e., the number of people with a given disease or condition at any time) of HF is increasing, despite a reduction in cardiovascular mortality. A recent study revealed 28,702 patients were hospitalized for first-time HF in Ontario between April 1994 and March 1997. (3) Women comprised 51% of the cohort. Eighty-five percent were aged 65 years or older, and 58% were aged 75 years or older. Patients with chronic HF experience shortness of breath, a limited capacity for exercise, high rates of hospitalization and rehospitalization, and die prematurely. (2;4) The New York Heart Association (NYHA) has provided a commonly used functional classification for the severity of HF (2;5): Class I: No limitation of physical activity. No symptoms with ordinary exertion. Class II: Slight limitations of physical activity. Ordinary activity causes symptoms. Class III: Marked limitation of physical activity. Less than ordinary activity causes symptoms. Asymptomatic at rest. Class IV: Inability to carry out any physical activity without discomfort. Symptoms at rest. The National Heart, Lung, and Blood Institute estimates that 35% of patients with HF are in functional NYHA class I; 35% are in class II; 25%, class III; and 5%, class IV. (5) Surveys (2) suggest that from 5% to 15% of patients with HF have persistent severe symptoms, and that the remainder of patients with HF is evenly divided between those with mild and moderately severe symptoms. Overall, patients with chronic, stable HF have an annual mortality rate of about 10%. (2) One-third of patients with new-onset HF will die within 6 months of diagnosis. These patients do not survive to enter the pool of those with “chronic” HF. About 60% of patients with incident HF will die within 3 years, and there is limited evidence that the overall prognosis has improved in the last 15 years. To date, the diagnosis and management of chronic HF has concentrated on patients with the clinical syndrome of HF accompanied by severe left ventricular systolic dysfunction. Major changes in treatment have resulted from a better understanding of the pathophysiology of HF and the results of large clinical trials. Treatment for chronic HF includes lifestyle management, drugs, cardiac surgery, or implantable pacemakers and defibrillators. Despite pharmacologic advances, which include diuretics, angiotensin-converting enzyme inhibitors, beta-blockers, spironolactone, and digoxin, many patients remain symptomatic on maximally tolerated doses. The Technology Owing to the limitations of drug therapy, cardiac transplantation and device therapies have been used to try to improve QoL and survival of patients with chronic HF. Ventricular pacing is an emerging treatment option for patients with severe HF that does not respond well to medical therapy. Traditionally, indications for pacing include bradyarrhythmia, sick sinus syndrome, atrioventricular block, and other indications, including combined sick sinus syndrome with atrioventricular block and neurocardiogenic syncope. Recently, BiV pacing as a new, adjuvant therapy for patients with chronic HF and mechanical dyssynchrony has been investigated. Ventricular dysfunction is a sign of HF; and, if associated with severe intraventricular conduction delay, it can cause dyssynchronous ventricular contractions resulting in decreased ventricular filling. The therapeutic intent is to activate both ventricles simultaneously, thereby improving the mechanical efficiency of the ventricles. About 30% of patients with chronic HF have intraventricular conduction defects. (6) These conduction abnormalities progress over time and lead to discoordinated contraction of an already hemodynamically compromised ventricle. Intraventricular conduction delay has been associated with clinical instability and an increased risk of death in patients with HF. (7) Hence, BiV pacing, which involves pacing left and right ventricles simultaneously, may provide a more coordinated pattern of ventricular contraction and thereby potentially reduce QRS duration, and intraventricular and interventricular asynchrony. People with advanced chronic HF, a wide QRS complex (i.e., the portion of the electrocardiogram comprising the Q, R, and S waves, together representing ventricular depolarization), low left ventricular ejection fraction and contraction dyssynchrony in a viable myocardium and normal sinus rhythm, are the target patients group for BiV pacing. One-half of all deaths in HF patients are sudden, and the mode of death is arrhythmic in most cases. Internal cardioverter defibrillators (ICDs) combined with BiV pacemakers are therefore being increasingly considered for patients with HF who are at high risk of sudden death. Current Implantation Technique for Cardiac Resynchronization Conventional dual-chamber pacemakers have only 2 leads: 1 placed in the right atrium and the other in the right ventricle. The technique used for BiV pacemaker implantation also uses right atrial and ventricular pacing leads, in addition to a left ventricle lead advanced through the coronary sinus into a vein that runs along the ventricular free wall. This permits simultaneous pacing of both ventricles to allow resynchronization of the left ventricle septum and free wall. Mode of Operation Permanent pacing systems consist of an implantable pulse generator that contains a battery and electronic circuitry, together with 1 (single-chamber pacemaker) or 2 (dual-chamber pacemaker) leads. Leads conduct intrinsic atrial or ventricular signals to the sensing circuitry and deliver the pulse generator charge to the myocardium (muscle of the heart). Complications of Biventricular Pacemaker Implantation The complications that may arise when a BiV pacemaker is implanted are similar to those that occur with standard pacemaker implantation, including pneumothorax, perforation of the great vessels or the myocardium, air embolus, infection, bleeding, and arrhythmias. Moreover, left ventricular pacing through the coronary sinus can be associated with rupture of the sinus as another complication. Conclusion of 2003 Review of Biventricular Pacemakers by the Medical Advisory Secretariat The randomized controlled trials (RCTs) the Medical Advisory Secretariat retrieved analyzed chronic HF patients that were assessed for up to 6 months. Other studies have been prospective, but nonrandomized, not double-blinded, uncontrolled and/or have had a limited or uncalculated sample size. Short-term studies have focused on acute hemodynamic analyses. The authors of the RCTs reported improved cardiac function and QoL up to 6 months after BiV pacemaker implantation; therefore, there is level 1 evidence that patients in ventricular dyssynchrony who remain symptomatic after medication might benefit from this technology. Based on evidence made available to the Medical Advisory Secretariat by a manufacturer, (8) it appears that these 6-month improvements are maintained at 12-month follow-up. To date, however, there is insufficient evidence to support the routine use of combined ICD/BiV devices in patients with chronic HF with prolonged QRS intervals. Summary of Updated Findings Since the 2003 Review Since the Medical Advisory Secretariat’s review in 2003 of biventricular pacemakers, 2 large RCTs have been published: COMPANION (9) and CARE-HF. (10) The characteristics of each trial are shown in Table 1. The COMPANION trial had a number of major methodological limitations compared with the CARE-HF trial. Table 1: Characteristics of the COMPANION and CARE-HF Trials* COMPANION, 2004 CARE-HF, 2005 Optimal Therapy vs. BiV Pacing vs. BiV Pacing/ICD† Optimal Therapy vs. BiV Pacing Population New York Heart Association class III/IV heart failure EF† ≤ 0.35 QRS† ≥ 120 ms N 1,520(optimal therapy, n = 308; BiV pacing, n = 617; BiV pacing/ICD, n = 595) 813 Follow-up (months) Median, 16 Mean, 29 Comment - Definition of “hospitalization” in primary outcome changed 3 times during trial w/o documentation in protocol and FDA† not notified (dominant outcome for composite endpoint).- Dropouts/withdrawals/crossovers not clearly described.- Study terminated early.- No direct comparison between BiV pacing vs. BiV pacing/ICD.- High number of patients withdrew from optimal therapy to device arms.- Not blinded. Not blinded * COMPANION; (9) CARE-HF. (10) † BiV indicates biventricular; ICD, implantable cardioverter defibrillator; EF, ejection fraction; QRS, the interval representing the Q, R and S waves on an electrocardiogram; FDA, United States Food and Drug Administration. Overall, CARE-HF showed that BiV pacing significantly improves mortality, QoL, and NYHA class in patients with severe HF and a wide QRS interval (Tables 2 and 3). Table 2: CARE-HF Results: Primary and Secondary Endpoints* Outcome Medical Therapy Alone(N = 404) Medical Therapy and BiV† Pacing†(N = 409) Hazard Ratio (95% CI) P NNT† No. (%) Patients No. (%) Patients Primary (Combined Endpoint) Death (any cause) or unplanned hospitalization for major cardiovascular event. 224 (55) 159 (39) 0.63 (0.51–0.77) < .001 6 Secondary Death (any cause) at 29 months 120 (30) 82 (20) 0.64 (0.48–0.85) < .002 10 0.60 (0.47–0.77) (at 36 months – grey literature) (11) 154 (38) 101 (25) < .0001 7 Death from any cause or unplanned hospitalization with worsening HF 191 (47) 118 (29) 0.54 (0.43–0.68) < .001 6 † BiV indicates biventricular; NNT, number needed to treat. * Cleland JGF, Daubert J, Erdmann E, Freemantle N, Gras D, Kappenberger L et al. The effect of cardiac resynchronization on morbidity and mortality in heart failure (CARE-HF). New England Journal of Medicine 2005; 352:1539-1549; Copyright 2003 Massachusettes Medical Society. All rights reserved. (10) Table 3: CARE H-F Results: NYHA Class and Quality of Life Scores* Outcome Medical Therapy Alone(N = 404) Medical Therapy and BiV Pacing(N = 409) Difference in Means P (95% CI) Mean (SD) at 90 days Mean (SD) at 90 days NYHA class 2.7 (0.9) 2.1 (1.0) 0.6 < .001 (0.4–0.7) Minnesota Living with Heart 40 (22) 31 (22) -10 < .001 Failure score† (-8 to -12) EuroQoL EQ-5D score‡ 0.63 (0.29) 0.70 (0.28) 0.08 < .001 (0.04–0.12) † Minnesota Living with Heart Failure scores range from 0 to 105; higher scores reflect poorer QoL. ‡ European Quality of Life–5 Dimensions scores range from -0.594 to 1.000; 1.000 indicates fully healthy; 0, dead * Cleland JGF, Daubert J, Erdmann E, Freemantle N, Gras D, Kappenberger L et al. The effect of cardiac resynchronization on morbidity and mortality in heart failure (CARE-HF). New England Journal of Medicine 2005; 352:1539-1549; Copyright 2005 Massachusettes Medical Society. All rights reserved.(10) GRADE Quality of Evidence The quality of these 3 trials was examined according to the GRADE Working Group criteria, (12) (Table 4). Quality refers to criteria such as the adequacy of allocation concealment, blinding, and follow-up. Consistency refers to the similarity of estimates of effect across studies. If there is an important unexplained inconsistency in the results, confidence in the estimate of effect for that outcome decreases. Differences in the direction of effect, the size of the differences in effect, and the significance of the differences guide the decision about whether important inconsistency exists. Directness refers to the extent to which the people interventions and outcome measures are similar to those of interest. For example, there may be uncertainty about the directness of the evidence if the people of interest are older, sicker, or have more comorbid conditions than do the people in the studies. As stated by the GRADE Working Group, (12) the following definitions were used in grading the quality of the evidence: High: Further research is very unlikely to change our confidence on the estimate of effect. Moderate: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low: Any estimate of effect is very uncertain. Table 4: Quality of Evidence: CARE-HF and COMPANION Trial Design Quality Consistency Directness Quality Grade CARE-HF RCT Not blinded. No important inconsistency. Direct. Moderate/High (BiV pacing only vs. medical therapy) Consistent with COMPANION in terms of mortality results.Consistent with previous studies regarding QoL and functional status results. COMPANION(BiV pacing only vs. combined BiV pacing/ICD vs. medical therapy) RCT Definition of “hospitalization” in primary outcome changed 3 times during trial without documentation in protocol and FDA not notified (dominant outcome for composite endpoint).Dropouts/withdrawals/crossovers not clearly described.Study terminated early.No direct comparison between BiV pacing vs. BiV pacing/ICD.High number of patients withdrew from optimal therapy to device arms.Not blinded. No important inconsistency for BiV pacing only.No other RCT prospectively examined the combined BiV pacing/ICD device in patients with NYHA III/IV HF and QRS > 120 ms and EF < 0.35 and refractory to drugs.No other RCT prospectively examined the prophylactic use of ICDs in patients with NYHA IV HF. Direct for BiV pacing only.No other RCT examined the prophylactic use of ICDs in patients with NYHA IV HF. Low Conclusions Overall, there is evidence that BiV pacemakers are effective for improving mortality, QoL, and functional status in patients with NYHA class III/IV HF, an EF less than 0.35, a QRS interval greater than 120 ms, who are refractory to drug therapy. As per the GRADE Working Group, recommendations considered the following 4 main factors: The tradeoffs, taking into account the estimated size of the effect for the main outcome, the confidence limits around those estimates, and the relative value placed on the outcome The quality of the evidence (Table 4) Translation of the evidence into practice in a specific setting, taking into consideration important factors that could be expected to modify the size of the expected effects such as proximity to a hospital or availability of necessary expertise Uncertainty about the baseline risk for the population of interest The GRADE Working Group also recommends that incremental costs of health care alternatives should be considered explicitly alongside the expected health benefits and harms. Recommendations rely on judgments about the value of the incremental health benefits in relation to the incremental costs. The last column in Table 5 shows the overall trade-off between benefits and harms and incorporates any risk/uncertainty. For BiV pacing, the overall GRADE and strength of the recommendation is moderate: the quality of the evidence is moderate/high (because of some uncertainty due to methodological limitations in the study design, e.g., no blinding), but there is also some risk/uncertainty in terms of the estimated prevalence and wide cost-effectiveness estimates (Table 5). For the combination BiV pacing/ICD, the overall GRADE and strength of the recommendation is weak—the quality of the evidence is low (because of uncertainty due to methodological limitations in the study design), but there is also some risk/uncertainty in terms of the estimated prevalence, high cost, and high budget impact (Table 5). There are indirect, low-quality comparisons of the effectiveness of BiV pacemakers compared with the combination BiV/ICD devices. A stronger recommendation can be made for BiV pacing only compared with the combination BiV/ICD device for patients with an EF less than or equal to 0.35, and a QRS interval over or equal to 120 ms, and NYHA III/IV symptoms, and refractory to optimal medical therapy (Table 5). There is moderate/high-quality evidence that BiV pacemakers significantly improve mortality, QoL, and functional status. There is low-quality evidence that combined BiV/ICD devices significantly improve mortality, QoL, and functional status. To date, there are no direct comparisons of the effectiveness of BiV pacemakers compared with the combined BiV/ICD devices in terms of mortality, QoL, and functional status. Table 5: Overall GRADE and Strength of Recommendation Quality Estimated Prevalence, Ontario NNT*Death (Any Cause) Cost-Effectiveness Cost in Ontario$(Millions) Overall Grade & Strength of Recommendation (Including Uncertainty) BiV* Pacing Moderate/high ~2,560 7 $7,000 to $59,000/QALY* 38–46~14–16/year over 4 years Moderate BiV Pacing/ICD* LowMajor study limitations ~2,560 14 ?Low quality data 74–82~27–29/year over 4 years Weak * BiV refers to biventricular; ICD, implantable cardioverter defibrillator; NNT, number needed to treat. PMID:23074464

  7. Ethical Issues in Cardiac Surgery

    PubMed Central

    Kavarana, Minoo N.; Sade, Robert M.

    2012-01-01

    While ethical behavior has always been part of cardiac surgical practice, ethical deliberation has only recently become an important component of cardiac surgical practice. Issues such as informed consent, conflict of interest, and professional self-regulation, among many others, have increasingly attracted the attention of cardiac surgeons. This review covers several broad topics of interest to cardiac surgeons and cardiologists, and treats several other topics more briefly. There is much uncertainty about what the future holds for cardiac surgical practice, research, and culture, and we discuss the background of ethical issues to serve as a platform for envisioning what is to come. PMID:22642634

  8. Maternal cardiac metabolism in pregnancy

    PubMed Central

    Liu, Laura X.; Arany, Zolt

    2014-01-01

    Pregnancy causes dramatic physiological changes in the expectant mother. The placenta, mostly foetal in origin, invades maternal uterine tissue early in pregnancy and unleashes a barrage of hormones and other factors. This foetal ‘invasion’ profoundly reprogrammes maternal physiology, affecting nearly every organ, including the heart and its metabolism. We briefly review here maternal systemic metabolic changes during pregnancy and cardiac metabolism in general. We then discuss changes in cardiac haemodynamic during pregnancy and review what is known about maternal cardiac metabolism during pregnancy. Lastly, we discuss cardiac diseases during pregnancy, including peripartum cardiomyopathy, and the potential contribution of aberrant cardiac metabolism to disease aetiology. PMID:24448314

  9. Biomechanics of Early Cardiac Development

    PubMed Central

    Goenezen, Sevan; Rennie, Monique Y.

    2012-01-01

    Biomechanics affect early cardiac development, from looping to the development of chambers and valves. Hemodynamic forces are essential for proper cardiac development, and their disruption leads to congenital heart defects. A wealth of information already exists on early cardiac adaptations to hemodynamic loading, and new technologies, including high resolution imaging modalities and computational modeling, are enabling a more thorough understanding of relationships between hemodynamics and cardiac development. Imaging and modeling approaches, used in combination with biological data on cell behavior and adaptation, are paving the road for new discoveries on links between biomechanics and biology and their effect on cardiac development and fetal programming. PMID:22760547

  10. Maternal cardiac metabolism in pregnancy.

    PubMed

    Liu, Laura X; Arany, Zolt

    2014-03-15

    Pregnancy causes dramatic physiological changes in the expectant mother. The placenta, mostly foetal in origin, invades maternal uterine tissue early in pregnancy and unleashes a barrage of hormones and other factors. This foetal 'invasion' profoundly reprogrammes maternal physiology, affecting nearly every organ, including the heart and its metabolism. We briefly review here maternal systemic metabolic changes during pregnancy and cardiac metabolism in general. We then discuss changes in cardiac haemodynamic during pregnancy and review what is known about maternal cardiac metabolism during pregnancy. Lastly, we discuss cardiac diseases during pregnancy, including peripartum cardiomyopathy, and the potential contribution of aberrant cardiac metabolism to disease aetiology. PMID:24448314

  11. [Cardiac amyloidosis. General review].

    PubMed

    Laraki, R

    1994-04-01

    Cardiac amyloidosis, most often of AL type, is a non-exceptional disease as it represents 5 to 10% of non-ischemic cardiomyopathies. It realizes typically a restrictive cardiomyopathy. Nevertheless the wide diversity of possible presentation makes it a "big shammer" which must be evoked in front of every unexplained cardiopathy after the age of forty. If some associated manifestations can rapidly suggest the diagnosis, as a peripheric neuropathy especially a carpal tunnel syndrome or palpebral ecchymosis, cardiac involvement can also evolve in an apparently isolated way. The most suggestive paraclinic elements for the diagnosis are, in one hand, the increased myocardial echogenicity with a "granular sparkling" appearance seen throughout all walls of the left ventricle and, in the other hand, the association of a thickened left ventricle and a low voltage (electrocardiogram could also show pseudo-infarct Q waves). In front of such aspects, the proof of amyloidosis is brought by an extra-cardiac biopsy or by scintigraphy with labelled serum amyloid P component, so that the indications of endomyocardial biopsy are very limited today. The identification of the amyloid nature of a cardiopathy has an direct therapeutic implication: it contra-indicates the use of digitalis, calcium channel blockers and beta-blockers. The treatment of AL amyloidosis (chemotherapy with alkylant agents) remains very unsatisfactory especially in the cardiac involvement which is the most frequent cause of death (in AL amyloidosis). Last, cardiac amyloidosis is a bad indication for transplantation which results are burden by rapid progression of deposits especially in the gastro-intestinal tract and the nervous system. PMID:8059146

  12. Cardiac telocytes were decreased during myocardial infarction and their therapeutic effects for ischaemic heart in rat.

    PubMed

    Zhao, Baoyin; Chen, Shang; Liu, Juanjuan; Yuan, Ziqiang; Qi, Xufeng; Qin, Junwen; Zheng, Xin; Shen, Xiaotao; Yu, Yanhong; Qnin, Thomas J; Chan, John Yeuk-Hon; Cai, Dongqing

    2013-01-01

    Recently, cardiac telocytes were found in the myocardium. However, the functional role of cardiac telocytes and possible changes in the cardiac telocyte population during myocardial infarction in the myocardium are not known. In this study, the role of the recently identified cardiac telocytes in myocardial infarction (MI) was investigated. Cardiac telocytes were distributed longitudinally and within the cross network of the myocardium, which was impaired during MI. Cardiac telocytes in the infarction zone were undetectable from approximately 4 days to 4 weeks after an experimental coronary occlusion was used to induce MI. Although cardiac telocytes in the non-ischaemic area of the ischaemic heart experienced cell death, the cell density increased approximately 2 weeks after experimental coronary occlusion. The cell density was then maintained at a level similar to that observed 1-4 days after left anterior descending coronary artery (LAD)-ligation, but was still lower than normal after 2 weeks. We also found that simultaneous transplantation of cardiac telocytes in the infarcted and border zones of the heart decreased the infarction size and improved myocardial function. These data indicate that cardiac telocytes, their secreted factors and microvesicles, and the microenvironment may be structurally and functionally important for maintenance of the physiological integrity of the myocardium. Rebuilding the cardiac telocyte network in the infarcted zone following MI may be beneficial for functional regeneration of the infarcted myocardium. PMID:23205601

  13. The Psycholinguistics of the Output Hypothesis.

    ERIC Educational Resources Information Center

    de Bot, Kees

    1996-01-01

    Elucidates the psycholinguistic mechanics of the "output hypothesis" and argues that output serves an important role in second language acquisition because it generates specific input the cognitive system needs to build up a coherent set of knowledge. The article hypothesizes that the locus of the effect of output is in the transition of…

  14. Evidence for increased cardiac compliance during exposure to simulated microgravity

    NASA Technical Reports Server (NTRS)

    Koenig, S. C.; Convertino, V. A.; Fanton, J. W.; Reister, C. A.; Gaffney, F. A.; Ludwig, D. A.; Krotov, V. P.; Trambovetsky, E. V.; Latham, R. D.

    1998-01-01

    We measured hemodynamic responses during 4 days of head-down tilt (HDT) and during graded lower body negative pressure (LBNP) in invasively instrumented rhesus monkeys to test the hypotheses that exposure to simulated microgravity increases cardiac compliance and that decreased stroke volume, cardiac output, and orthostatic tolerance are associated with reduced left ventricular peak dP/dt. Six monkeys underwent two 4-day (96 h) experimental conditions separated by 9 days of ambulatory activities in a crossover counterbalance design: 1) continuous exposure to 10 degrees HDT and 2) approximately 12-14 h per day of 80 degrees head-up tilt and 10-12 h supine (control condition). Each animal underwent measurements of central venous pressure (CVP), left ventricular and aortic pressures, stroke volume, esophageal pressure (EsP), plasma volume, alpha1- and beta1-adrenergic responsiveness, and tolerance to LBNP. HDT induced a hypovolemic and hypoadrenergic state with reduced LBNP tolerance compared with the control condition. Decreased LBNP tolerance with HDT was associated with reduced stroke volume, cardiac output, and peak dP/dt. Compared with the control condition, a 34% reduction in CVP (P = 0.010) and no change in left ventricular end-diastolic area during HDT was associated with increased ventricular compliance (P = 0.0053). Increased cardiac compliance could not be explained by reduced intrathoracic pressure since EsP was unaltered by HDT. Our data provide the first direct evidence that increased cardiac compliance was associated with headward fluid shifts similar to those induced by exposure to spaceflight and that reduced orthostatic tolerance was associated with lower cardiac contractility.

  15. Are Electronic Cardiac Devices Still Evolving?

    PubMed Central

    Mabo, P.

    2014-01-01

    Summary Objectives The goal of this paper is to review some important issues occurring during the past year in Implantable devices. Methods First cardiac implantable device was proposed to maintain an adequate heart rate, either because the heart’s natural pacemaker is not fast enough, or there is a block in the heart’s electrical conduction system. During the last forty years, pacemakers have evolved considerably and become programmable and allow to configure specific patient optimum pacing modes. Various technological aspects (electrodes, connectors, algorithms diagnosis, therapies, …) have been progressed and cardiac implants address several clinical applications: management of arrhythmias, cardioversion / defibrillation and cardiac resynchronization therapy. Results Observed progress was the miniaturization of device, increased longevity, coupled with efficient pacing functions, multisite pacing modes, leadless pacing and also a better recognition of supraventricular or ventricular tachycardia’s in order to deliver appropriate therapy. Subcutaneous implant, new modes of stimulation (leadless implant or ultrasound lead), quadripolar lead and new sensor or new algorithm for the hemodynamic management are introduced and briefly described. Each times, the main result occurring during the two past years are underlined and repositioned from the history, remaining limitations are also addressed. Conclusion Some important technological improvements were described. Nevertheless, news trends for the future are also considered in a specific session such as the remote follow-up of the patient or the treatment of heart failure by neuromodulation. PMID:25123732

  16. Reduced pallidal output causes dystonia.

    PubMed

    Nambu, Atsushi; Chiken, Satomi; Shashidharan, Pullanipally; Nishibayashi, Hiroki; Ogura, Mitsuhiro; Kakishita, Koji; Tanaka, Satoshi; Tachibana, Yoshihisa; Kita, Hitoshi; Itakura, Toru

    2011-01-01

    Dystonia is a neurological disorder characterized by sustained or repetitive involuntary muscle contractions and abnormal postures. In the present article, we will introduce our recent electrophysiological studies in hyperkinetic transgenic mice generated as a model of DYT1 dystonia and in a human cervical dystonia patient, and discuss the pathophysiology of dystonia on the basis of these electrophysiological findings. Recording of neuronal activity in the awake state of DYT1 dystonia model mice revealed reduced spontaneous activity with bursts and pauses in both internal (GPi) and external (GPe) segments of the globus pallidus. Electrical stimulation of the primary motor cortex evoked responses composed of excitation and subsequent long-lasting inhibition, the latter of which was never observed in normal mice. In addition, somatotopic arrangements were disorganized in the GPi and GPe of dystonia model mice. In a human cervical dystonia patient, electrical stimulation of the primary motor cortex evoked similar long-lasting inhibition in the GPi and GPe. Thus, reduced GPi output may cause increased thalamic and cortical activity, resulting in the involuntary movements observed in dystonia. PMID:22164134

  17. Reduced Pallidal Output Causes Dystonia

    PubMed Central

    Nambu, Atsushi; Chiken, Satomi; Shashidharan, Pullanipally; Nishibayashi, Hiroki; Ogura, Mitsuhiro; Kakishita, Koji; Tanaka, Satoshi; Tachibana, Yoshihisa; Kita, Hitoshi; Itakura, Toru

    2011-01-01

    Dystonia is a neurological disorder characterized by sustained or repetitive involuntary muscle contractions and abnormal postures. In the present article, we will introduce our recent electrophysiological studies in hyperkinetic transgenic mice generated as a model of DYT1 dystonia and in a human cervical dystonia patient, and discuss the pathophysiology of dystonia on the basis of these electrophysiological findings. Recording of neuronal activity in the awake state of DYT1 dystonia model mice revealed reduced spontaneous activity with bursts and pauses in both internal (GPi) and external (GPe) segments of the globus pallidus. Electrical stimulation of the primary motor cortex evoked responses composed of excitation and subsequent long-lasting inhibition, the latter of which was never observed in normal mice. In addition, somatotopic arrangements were disorganized in the GPi and GPe of dystonia model mice. In a human cervical dystonia patient, electrical stimulation of the primary motor cortex evoked similar long-lasting inhibition in the GPi and GPe. Thus, reduced GPi output may cause increased thalamic and cortical activity, resulting in the involuntary movements observed in dystonia. PMID:22164134

  18. Model output: fact or artefact?

    NASA Astrophysics Data System (ADS)

    Melsen, Lieke

    2015-04-01

    As a third-year PhD-student, I relatively recently entered the wonderful world of scientific Hydrology. A science that has many pillars that directly impact society, for example with the prediction of hydrological extremes (both floods and drought), climate change, applications in agriculture, nature conservation, drinking water supply, etcetera. Despite its demonstrable societal relevance, hydrology is often seen as a science between two stools. Like Klemeš (1986) stated: "By their academic background, hydrologists are foresters, geographers, electrical engineers, geologists, system analysts, physicists, mathematicians, botanists, and most often civil engineers." Sometimes it seems that the engineering genes are still present in current hydrological sciences, and this results in pragmatic rather than scientific approaches for some of the current problems and challenges we have in hydrology. Here, I refer to the uncertainty in hydrological modelling that is often neglected. For over thirty years, uncertainty in hydrological models has been extensively discussed and studied. But it is not difficult to find peer-reviewed articles in which it is implicitly assumed that model simulations represent the truth rather than a conceptualization of reality. For instance in trend studies, where data is extrapolated 100 years ahead. Of course one can use different forcing datasets to estimate the uncertainty of the input data, but how to prevent that the output is not a model artefact, caused by the model structure? Or how about impact studies, e.g. of a dam impacting river flow. Measurements are often available for the period after dam construction, so models are used to simulate river flow before dam construction. Both are compared in order to qualify the effect of the dam. But on what basis can we tell that the model tells us the truth? Model validation is common nowadays, but validation only (comparing observations with model output) is not sufficient to assume that a model reflects reality. E.g. due to nonuniqueness or so called equifinality; different model construction lead to same output (Oreskes et al., 1994, Beven, 2005). But also because validation only does not provide us information on whether we are 'right for the wrong reasons' (Kirchner, 2006; Oreskes et al., 1994). We can never know how right or wrong our models are, because we do not fully understand reality. But we can estimate the uncertainty from the model and the input data itself. Many techniques have been developed that help in estimating model uncertainty. E.g. model structural uncertainty, studied in the FUSE framework (Clark et al., 2008), parameter uncertainty with GLUE (Beven and Binley, 1992) and DREAM (Vrugt et al., 2008), input data uncertainty using BATEA (Kavetski et al., 2006). These are just some examples that pop-up in a first search. But somehow, these techniques are only used and applied in studies that focus on the model uncertainty itself, and hardly ever occur in studies that have a research question outside of the uncertainty-region. We know that models don't tell us the truth, but we have the tendency to claim they are, based on validation only. A model is always a simplification of reality, which by definition leads to uncertainty when model output and observations of reality are compared. The least we could do is estimate the uncertainty of the model and the data itself. My question therefore is: As a scientist, can we accept that we believe things of which we know they might not be true? And secondly: How to deal with this? How should model uncertainty change the way we communicate scientific results? References Beven, K., and A. Binley, The future of distributed models: Model calibration and uncertainty prediction, HP 6 (1992). Beven, K., A manifesto for the equifinality thesis, JoH 320 (2006). Clark, M.P., A.G. Slater, D.E. Rupp, R.A. Woods, J.A. Vrugt, H.V. Gupta, T. Wagener and L.E. Hay, Framework for Understanding Structural Errors (FUSE): A modular framework to diagnose differences between hydrological models, WRR 44 (2008). Kavetski, D., G. Kuczera and S.W. Franks, Bayesian analysis of input uncertainty in hydrological modeling: 1. Theory, WRR 42 (2006). Kirchner, J.W., Getting the right answers for the right reasons: Linking measurements, analyses, and models to advance the science of hydrology, WRR 42 (2006). Klemeš, V., Dilettantism in Hydrology: Transition or Destiny?, WRR 22-9 (1986). Oreskes, N., K. Shrader-Frechette, and K. Belitz, Verification, Validation and Confirmation of Numerical Models in Earth Sciences, SCIENCE 263 (1994). Vrugt, J.A., C.J.F. ter Braak, M.P. Clar, J.M. Hyman, and B.A. Robinson, Treatment of input uncertainty in hydrologic modeling: Doing hydrology backward with Markov chain Monte Carlo simulation, WRR 44, (2008).

  19. Low-dose exposure of silica nanoparticles induces cardiac dysfunction via neutrophil-mediated inflammation and cardiac contraction in zebrafish embryos.

    PubMed

    Duan, Junchao; Yu, Yang; Li, Yang; Li, Yanbo; Liu, Hongcui; Jing, Li; Yang, Man; Wang, Ji; Li, Chunqi; Sun, Zhiwei

    2016-06-01

    The toxicity mechanism of nanoparticles on vertebrate cardiovascular system is still unclear, especially on the low-level exposure. This study was to explore the toxic effect and mechanisms of low-dose exposure of silica nanoparticles (SiNPs) on cardiac function in zebrafish embryos via the intravenous microinjection. The dosage of SiNPs was based on the no observed adverse effect level (NOAEL) of malformation assessment in zebrafish embryos. The mainly cardiac toxicity phenotypes induced by SiNPs were pericardial edema and bradycardia but had no effect on atrioventricular block. Using o-Dianisidine for erythrocyte staining, the cardiac output of zebrafish embryos was decreased in a dose-dependent manner. Microarray analysis and bioinformatics analysis were performed to screen the differential expression genes and possible pathway involved in cardiac function. SiNPs induced whole-embryo oxidative stress and neutrophil-mediated cardiac inflammation in Tg(mpo:GFP) zebrafish. Inflammatory cells were observed in atrium of SiNPs-treated zebrafish heart by histopathological examination. In addition, the expression of TNNT2 protein, a cardiac contraction marker in heart tissue had been down-regulated compared to control group using immunohistochemistry. Confirmed by qRT-PCR and western blot assays, results showed that SiNPs inhibited the calcium signaling pathway and cardiac muscle contraction via the down-regulated of related genes, such as ATPase-related genes (atp2a1l, atp1b2b, atp1a3b), calcium channel-related genes (cacna1ab, cacna1da) and the regulatory gene tnnc1a for cardiac troponin C. Moreover, the protein level of TNNT2 was decreased in a dose-dependent manner. For the first time, our results demonstrated that SiNPs induced cardiac dysfunction via the neutrophil-mediated cardiac inflammation and cardiac contraction in zebrafish embryos. PMID:26551753

  20. Pediatric cardiac surgery in developing countries.

    PubMed

    Rao, Suresh G

    2007-01-01

    Pediatric cardiac surgery in developing countries is a major challenge. It is a challenge to employ evolving methods to cater to the surgical needs of a very large number of children with congenital heart defects while dealing with severe budgetary constraints, finding funding to maintain the program, and maintaining quality in the backdrop of constant turnover of trained medical, nursing, and other paramedical personnel. Choosing the best procedure to achieve maximum palliation at lower cost and, when possible, giving priority for one-stage corrective procedures, albeit at a higher risk, calls for practice modifications. Despite improved infrastructure and surgical skills in recent years, in some developing countries, logistics, affordability, late presentation, nutritional issues, staffing, and unfavorable economics continue to negatively influence the overall results compared to those of developed nations. PMID:17486389

  1. Magnetic resonance imaging analysis of cardiac cycle events in diabetic rats: the effect of angiotensin-converting enzyme inhibition.

    PubMed

    Al-Shafei, Ahmad I M; Wise, R G; Gresham, G A; Carpenter, T A; Hall, L D; Huang, Christopher L H

    2002-01-15

    Non-invasive magnetic resonance imaging (MRI) was used to characterize changes in left and right ventricular cardiac cycles following induction of experimental, streptozotocin (STZ)-induced, diabetes in male Wistar rats at different ages. The effects of the angiotensin-converting enzyme (ACE) inhibitor captopril upon such chronic physiological changes were then evaluated, also for the first time. Diabetes was induced at the age of 7 weeks in two experimental groups, of which one group was subsequently maintained on captopril (2 g l(-1))-containing drinking water, and at 10 and 13 weeks in two further groups. The fifth group provided age-matched controls. All groups (each n = 4 animals) were scanned consistently at 16 weeks, in parallel with timings used in earlier studies that employed this experimental model. Cine magnetic resonance (MR) image acquisition provided transverse sections through both ventricles at twelve time points covering systole and most of diastole. These yielded reconstructions of cardiac anatomy used to derive critical functional indices and their dependence upon time following the triggering electrocardiographic R waves. The left and right ventricular end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fractions (EF) calculated from each, control and experimental, group showed matching values. This confirmed a necessary condition requiring balanced right and left ventricular outputs and further suggested that STZ-induced diabetes produced physiological changes in both ventricles. Absolute left and right ventricular SVs were significantly altered in all diabetic animals; EDVs and EFs significantly altered in animals diabetic from 7 and 10 but not 13 weeks. When normalized to body weight, left and right ventricular SVs had significantly altered in animals diabetic from 7 and 10 weeks but not 13 weeks. Normalized left ventricular EDVs were also significantly altered in animals diabetic from 7 and 10 weeks. However, normalized right ventricular EDVs were significantly altered only in animals made diabetic from 7 weeks. Diabetic hearts showed major kinetic changes in left and right ventricular contraction (ejection) and relaxation (filling). Both the initial rates of volume change (dV/dt) in both ventricles and the plots of dV/dt values through the cardiac cycle demonstrated more gradual developments of tension during systole and relaxation during diastole. Estimates of the derived left ventricular performance parameters of cardiac output, cardiac power output and stroke work in control animals were comparable with human values when normalized to both body (or cardiac) weight and heart rate. All deteriorated with diabetes. Comparisons of experimental groups diabetic from 7 weeks demonstrated that captopril treatment relieved the alterations in critical volumes, dependence of SV upon EDV, kinetics of systolic contraction and diastolic relaxation and in the derived indicators of ventricular performance. This study represents the first demonstration using non-invasive MRI of early, chronic changes in diastolic filling and systolic ejection in both the left and the right ventricles and of their amelioration by ACE inhibition following STZ-induction of diabetes in intact experimental animals. PMID:11790819

  2. Design of a specialized computer for on-line monitoring of cardiac stroke volume

    NASA Technical Reports Server (NTRS)

    Webb, J. A., Jr.; Gebben, V. D.

    1972-01-01

    The design of a specialized analog computer for on-line determination of cardiac stroke volume by means of a modified version of the pressure pulse contour method is presented. The design consists of an analog circuit for computation and a timing circuit for detecting necessary events on the pressure waveform. Readouts of arterial pressures, systolic duration, heart rate, percent change in stroke volume, and percent change in cardiac output are provided for monitoring cardiac patients. Laboratory results showed that computational accuracy was within 3 percent, while animal experiments verified the operational capability of the computer. Patient safety considerations are also discussed.

  3. Optical Waveguide Output Couplers Fabricated in Polymers

    NASA Technical Reports Server (NTRS)

    Watson, Michael D.; Abushagur, Mustafa A. G.; Ashley, Paul R.; Johnson-Cole, Helen

    1998-01-01

    Waveguide output couplers fabricated in Norland Optical Adhesive (NOA) #81 and AMOCO Ultradel 9020D polyimide are investigated. The output couplers are implemented using periodic relief gratings on a planar waveguide. Design theory of the couplers is based on the perturbation approach. Coupling of light from waveguide propagation modes to output radiation modes is described by coupled mode theory and the transmission line approximation of the perturbed area (grating structure). Using these concepts, gratings can be accurately designed to output a minimum number of modes at desired output angles. Waveguide couplers were designed using these concepts. These couplers were fabricated and analyzed for structural accuracy, output beam accuracy, and output efficiency. The results for the two different materials are compared.

  4. Endothelin receptor B, a candidate gene from human studies at high altitude, improves cardiac tolerance to hypoxia in genetically engineered heterozygote mice.

    PubMed

    Stobdan, Tsering; Zhou, Dan; Ao-Ieong, Eilleen; Ortiz, Daniel; Ronen, Roy; Hartley, Iain; Gan, Zhuohui; McCulloch, Andrew D; Bafna, Vineet; Cabrales, Pedro; Haddad, Gabriel G

    2015-08-18

    To better understand human adaptation to stress, and in particular to hypoxia, we took advantage of one of nature's experiments at high altitude (HA) and studied Ethiopians, a population that is well-adapted to HA hypoxic stress. Using whole-genome sequencing, we discovered that EDNRB (Endothelin receptor type B) is a candidate gene involved in HA adaptation. To test whether EDNRB plays a critical role in hypoxia tolerance and adaptation, we generated EdnrB knockout mice and found that when EdnrB (-/+) heterozygote mice are treated with lower levels of oxygen (O2), they tolerate various levels of hypoxia (even extreme hypoxia, e.g., 5% O2) very well. For example, they maintain ejection fraction, cardiac contractility, and cardiac output in severe hypoxia. Furthermore, O2 delivery to vital organs was significantly higher and blood lactate was lower in EdnrB (-/+) compared with wild type in hypoxia. Tissue hypoxia in brain, heart, and kidney was lower in EdnrB (-/+) mice as well. These data demonstrate that a lower level of EDNRB significantly improves cardiac performance and tissue perfusion under various levels of hypoxia. Transcriptomic profiling of left ventricles revealed three specific genes [natriuretic peptide type A (Nppa), sarcolipin (Sln), and myosin light polypeptide 4 (Myl4)] that were oppositely expressed (q < 0.05) between EdnrB (-/+) and wild type. Functions related to these gene networks were consistent with a better cardiac contractility and performance. We conclude that EDNRB plays a key role in hypoxia tolerance and that a lower level of EDNRB contributes, at least in part, to HA adaptation in humans. PMID:26240367

  5. Effects of autonomic balance and fluid and electrolyte changes on cardiac function in infarcted rats: A serial study of sexual dimorphism.

    PubMed

    Souza, N S; Dos-Santos, R C; Silveira, Anderson Luiz Bezerra da; R, Sonoda-Côrtes; Gantus, Michel Alexandre Villani; Fortes, F S; Olivares, Emerson Lopes

    2016-04-01

    Premenopausal women are known to show lower incidence of cardiovascular disease than men. During myocardial infarction (MI), homeostatic responses are activated, including the sympathetic autonomic nervous system and the rennin-angiotensin-aldosterone system, which is related to the fluid and electrolyte balance, both aiming to maintain cardiac output. This study sought to perform a serial evaluation of sexual dimorphism in cardiac autonomic control and fluid and electrolyte balance during the development of MI-induced heart failure in rats. Experimental MI was induced in male (M) and female (F) adult (7-9 weeks of age) Wistar rats. The animals were placed in metabolic cages to assess fluid intake and urine volume 1 and 4 weeks after inducing MI (male myocardial infarction (MMI) and female myocardial infarction (FMI) groups). They subsequently underwent echocardiographic evaluation and spectral analysis of heart rate variability. After completing each protocol, the animals were killed for postmortem evaluation and histology. The MMI group showed earlier and more intense cardiac morphological and functional changes than the FMI group, although the extent of MI did not differ between groups (P > 0.05). The MMI group showed higher sympathetic modulation and sodium and water retention than the FMI group (P < 0.05), which may partly explain both the echocardiographic and pathological findings. Females subjected to infarction seem to show attenuation of sympathetic modulation, more favourable fluid and electrolyte balances, and better preserved cardiac function compared to males subjected to the same infarction model. PMID:26748814

  6. Endothelin receptor B, a candidate gene from human studies at high altitude, improves cardiac tolerance to hypoxia in genetically engineered heterozygote mice

    PubMed Central

    Stobdan, Tsering; Zhou, Dan; Ao-Ieong, Eilleen; Ortiz, Daniel; Ronen, Roy; Hartley, Iain; Gan, Zhuohui; McCulloch, Andrew D.; Bafna, Vineet; Cabrales, Pedro; Haddad, Gabriel G.

    2015-01-01

    To better understand human adaptation to stress, and in particular to hypoxia, we took advantage of one of nature’s experiments at high altitude (HA) and studied Ethiopians, a population that is well-adapted to HA hypoxic stress. Using whole-genome sequencing, we discovered that EDNRB (Endothelin receptor type B) is a candidate gene involved in HA adaptation. To test whether EDNRB plays a critical role in hypoxia tolerance and adaptation, we generated EdnrB knockout mice and found that when EdnrB−/+ heterozygote mice are treated with lower levels of oxygen (O2), they tolerate various levels of hypoxia (even extreme hypoxia, e.g., 5% O2) very well. For example, they maintain ejection fraction, cardiac contractility, and cardiac output in severe hypoxia. Furthermore, O2 delivery to vital organs was significantly higher and blood lactate was lower in EdnrB−/+ compared with wild type in hypoxia. Tissue hypoxia in brain, heart, and kidney was lower in EdnrB−/+ mice as well. These data demonstrate that a lower level of EDNRB significantly improves cardiac performance and tissue perfusion under various levels of hypoxia. Transcriptomic profiling of left ventricles revealed three specific genes [natriuretic peptide type A (Nppa), sarcolipin (Sln), and myosin light polypeptide 4 (Myl4)] that were oppositely expressed (q < 0.05) between EdnrB−/+ and wild type. Functions related to these gene networks were consistent with a better cardiac contractility and performance. We conclude that EDNRB plays a key role in hypoxia tolerance and that a lower level of EDNRB contributes, at least in part, to HA adaptation in humans. PMID:26240367

  7. Basal Ganglia Outputs Map Instantaneous Position Coordinates during Behavior

    PubMed Central

    Barter, Joseph W.; Li, Suellen; Sukharnikova, Tatyana; Rossi, Mark A.; Bartholomew, Ryan A.

    2015-01-01

    The basal ganglia (BG) are implicated in many movement disorders, yet how they contribute to movement remains unclear. Using wireless in vivo recording, we measured BG output from the substantia nigra pars reticulata (SNr) in mice while monitoring their movements with video tracking. The firing rate of most nigral neurons reflected Cartesian coordinates (either x- or y-coordinates) of the animal's head position during movement. The firing rates of SNr neurons are either positively or negatively correlated with the coordinates. Using an egocentric reference frame, four types of neurons can be classified: each type increases firing during movement in a particular direction (left, right, up, down), and decreases firing during movement in the opposite direction. Given the high correlation between the firing rate and the x and y components of the position vector, the movement trajectory can be reconstructed from neural activity. Our results therefore demonstrate a quantitative and continuous relationship between BG output and behavior. Thus, a steady BG output signal from the SNr (i.e., constant firing rate) is associated with the lack of overt movement, when a stable posture is maintained by structures downstream of the BG. Any change in SNr firing rate is associated with a change in position (i.e., movement). We hypothesize that the SNr output quantitatively determines the direction, velocity, and amplitude of voluntary movements. By changing the reference signals to downstream position control systems, the BG can produce transitions in body configurations and initiate actions. PMID:25673860

  8. Basal ganglia outputs map instantaneous position coordinates during behavior.

    PubMed

    Barter, Joseph W; Li, Suellen; Sukharnikova, Tatyana; Rossi, Mark A; Bartholomew, Ryan A; Yin, Henry H

    2015-02-11

    The basal ganglia (BG) are implicated in many movement disorders, yet how they contribute to movement remains unclear. Using wireless in vivo recording, we measured BG output from the substantia nigra pars reticulata (SNr) in mice while monitoring their movements with video tracking. The firing rate of most nigral neurons reflected Cartesian coordinates (either x- or y-coordinates) of the animal's head position during movement. The firing rates of SNr neurons are either positively or negatively correlated with the coordinates. Using an egocentric reference frame, four types of neurons can be classified: each type increases firing during movement in a particular direction (left, right, up, down), and decreases firing during movement in the opposite direction. Given the high correlation between the firing rate and the x and y components of the position vector, the movement trajectory can be reconstructed from neural activity. Our results therefore demonstrate a quantitative and continuous relationship between BG output and behavior. Thus, a steady BG output signal from the SNr (i.e., constant firing rate) is associated with the lack of overt movement, when a stable posture is maintained by structures downstream of the BG. Any change in SNr firing rate is associated with a change in position (i.e., movement). We hypothesize that the SNr output quantitatively determines the direction, velocity, and amplitude of voluntary movements. By changing the reference signals to downstream position control systems, the BG can produce transitions in body configurations and initiate actions. PMID:25673860

  9. PREVIMER : Meteorological inputs and outputs

    NASA Astrophysics Data System (ADS)

    Ravenel, H.; Lecornu, F.; Kerlguer, L.

    2009-09-01

    PREVIMER is a pre-operational system aiming to provide a wide range of users, from private individuals to professionals, with short-term forecasts about the coastal environment along the French coastlines bordering the English Channel, the Atlantic Ocean, and the Mediterranean Sea. Observation data and digital modelling tools first provide 48-hour (probably 96-hour by summer 2009) forecasts of sea states, currents, sea water levels and temperatures. The follow-up of an increasing number of biological parameters will, in time, complete this overview of coastal environment. Working in partnership with the French Naval Hydrographic and Oceanographic Service (Service Hydrographique et Ocanographique de la Marine, SHOM), the French National Weather Service (Mto-France), the French public science and technology research institute (Institut de Recherche pour le Dveloppement, IRD), the European Institute of Marine Studies (Institut Universitaire Europen de la Mer, IUEM) and many others, IFREMER (the French public institute fo marine research) is supplying the technologies needed to ensure this pertinent information, available daily on Internet at http://www.previmer.org, and stored at the Operational Coastal Oceanographic Data Centre. Since 2006, PREVIMER publishes the results of demonstrators assigned to limited geographic areas and to specific applications. This system remains experimental. The following topics are covered : Hydrodynamic circulation, sea states, follow-up of passive tracers, conservative or non-conservative (specifically of microbiological origin), biogeochemical state, primary production. Lastly, PREVIMER provides researchers and R&D departments with modelling tools and access to the database, in which the observation data and the modelling results are stored, to undertake environmental studies on new sites. The communication will focus on meteorological inputs to and outputs from PREVIMER. It will draw the lessons from almost 3 years during which the system has been operational almost everyday and propose perspectives in terms of technical improvements and possible business models.

  10. Cardiac nuclear medicine

    SciTech Connect

    Gerson, M.C.

    1987-01-01

    The book begins with a review of the radionuclide methods available for evaluating cardiac perfusion and function. The authors discuss planar and tomographic thallium myocardial imaging, first-pass and equilibrium radionuclide angiography, and imaging with infarct-avid tracers. Several common but more specialized procedures are then reviewed: nonogemetric measurement of left ventricular volume, phase (Fourier) analysis, stroke volume ratio, right ventricular function, and diastolic function. A separate chapter is devoted to drug interventions and in particular the use of radionuclide ventriculography to monitor doxorubicin toxicity and therapy of congestive heart failure. The subsequent chapters provide a comprehensive guide to test selection, accuracy, and results in acute myocardial infarction, in postmyocardial infarction, in chronic coronary artery disease, before and after medical or surgical revascularization, in valvular heart disease, in cardiomyopathies, and in cardiac trauma.

  11. Cardiac adaptations of bullfrog tadpoles in response to chytrid infection.

    PubMed

    Salla, Raquel Fernanda; Gamero, Fernando Urban; Ribeiro, Larissa Rodrigues; Rizzi, Gisele Miglioranza; Medico, Samuel Espinosa Dal; Rissoli, Rafael Zanelli; Vieira, Conrado Augusto; Silva-Zacarin, Elaine Cristina Mathias; Leite, Domingos Silva; Abdalla, Fábio Camargo; Toledo, Luis Felipe; Costa, Monica Jones

    2015-08-01

    The chytrid fungus Batrachochytrium dendrobatidis (Bd) can result in heart failure in Bd-susceptible species. Since Bd infection generally does not cause mortality in North American bullfrogs, the aim of this work was to verify whether this species presents any cardiac adaptation that could improve the tolerance to the fungus. Thus, we analyzed tadpoles' activity level, relative ventricular mass, ventricle morphology, in loco heart frequency, and in vitro cardiac function. The results indicate that infected animals present an increase in both ventricular relative mass and in myofibrils' incidence, which accompanied the increase in myocytes' diameter. Such morphological alterations enabled an increase in the in vitro twitch force that, in vivo, would result in elevation of the cardiac stroke volume. This response requires much less energy expenditure than an elevation in heart frequency, but still enables the heart to pump a higher volume of blood per minute (i.e., an increase in cardiac output). As a consequence, the energy saved in the regulation of the cardiac function of Bd-infected tadpoles can be employed in other homeostatic adjustments to avoid the lethal effect of the fungus. Whether other species present this ability, and to what extent, remains uncertain, but such possible interspecific variability might explain different mortality rates among different species of Bd-infected amphibians. PMID:26055358

  12. Neuromodulation for cardiac arrhythmia.

    PubMed

    Hou, Yuemei; Zhou, Qina; Po, Sunny S

    2016-02-01

    The autonomic nervous system is known to play a significant role in the genesis and maintenance of arrhythmias. Neuromodulation, mostly designed to increase the parasympathetic tone and suppress the sympathetic tone, has become an emerging therapeutic strategy for the treatment of arrhythmias. Emerging therapeutic approaches include cervical vagal stimulation, transcutaneous auricular vagal stimulation, baroreceptor activation therapy spinal cord stimulation, ganglionated plexi ablation, renal sympathetic denervation, and left cardiac sympathetic denervation. PMID:26440550

  13. Human cardiac stem cells.

    PubMed

    Bearzi, Claudia; Rota, Marcello; Hosoda, Toru; Tillmanns, Jochen; Nascimbene, Angelo; De Angelis, Antonella; Yasuzawa-Amano, Saori; Trofimova, Irina; Siggins, Robert W; Lecapitaine, Nicole; Cascapera, Stefano; Beltrami, Antonio P; D'Alessandro, David A; Zias, Elias; Quaini, Federico; Urbanek, Konrad; Michler, Robert E; Bolli, Roberto; Kajstura, Jan; Leri, Annarosa; Anversa, Piero

    2007-08-28

    The identification of cardiac progenitor cells in mammals raises the possibility that the human heart contains a population of stem cells capable of generating cardiomyocytes and coronary vessels. The characterization of human cardiac stem cells (hCSCs) would have important clinical implications for the management of the failing heart. We have established the conditions for the isolation and expansion of c-kit-positive hCSCs from small samples of myocardium. Additionally, we have tested whether these cells have the ability to form functionally competent human myocardium after infarction in immunocompromised animals. Here, we report the identification in vitro of a class of human c-kit-positive cardiac cells that possess the fundamental properties of stem cells: they are self-renewing, clonogenic, and multipotent. hCSCs differentiate predominantly into cardiomyocytes and, to a lesser extent, into smooth muscle cells and endothelial cells. When locally injected in the infarcted myocardium of immunodeficient mice and immunosuppressed rats, hCSCs generate a chimeric heart, which contains human myocardium composed of myocytes, coronary resistance arterioles, and capillaries. The human myocardium is structurally and functionally integrated with the rodent myocardium and contributes to the performance of the infarcted heart. Differentiated human cardiac cells possess only one set of human sex chromosomes excluding cell fusion. The lack of cell fusion was confirmed by the Cre-lox strategy. Thus, hCSCs can be isolated and expanded in vitro for subsequent autologous regeneration of dead myocardium in patients affected by heart failure of ischemic and nonischemic origin. PMID:17709737

  14. Human cardiac stem cells

    PubMed Central

    Bearzi, Claudia; Rota, Marcello; Hosoda, Toru; Tillmanns, Jochen; Nascimbene, Angelo; De Angelis, Antonella; Yasuzawa-Amano, Saori; Trofimova, Irina; Siggins, Robert W.; LeCapitaine, Nicole; Cascapera, Stefano; Beltrami, Antonio P.; D'Alessandro, David A.; Zias, Elias; Quaini, Federico; Urbanek, Konrad; Michler, Robert E.; Bolli, Roberto; Kajstura, Jan; Leri, Annarosa; Anversa, Piero

    2007-01-01

    The identification of cardiac progenitor cells in mammals raises the possibility that the human heart contains a population of stem cells capable of generating cardiomyocytes and coronary vessels. The characterization of human cardiac stem cells (hCSCs) would have important clinical implications for the management of the failing heart. We have established the conditions for the isolation and expansion of c-kit-positive hCSCs from small samples of myocardium. Additionally, we have tested whether these cells have the ability to form functionally competent human myocardium after infarction in immunocompromised animals. Here, we report the identification in vitro of a class of human c-kit-positive cardiac cells that possess the fundamental properties of stem cells: they are self-renewing, clonogenic, and multipotent. hCSCs differentiate predominantly into cardiomyocytes and, to a lesser extent, into smooth muscle cells and endothelial cells. When locally injected in the infarcted myocardium of immunodeficient mice and immunosuppressed rats, hCSCs generate a chimeric heart, which contains human myocardium composed of myocytes, coronary resistance arterioles, and capillaries. The human myocardium is structurally and functionally integrated with the rodent myocardium and contributes to the performance of the infarcted heart. Differentiated human cardiac cells possess only one set of human sex chromosomes excluding cell fusion. The lack of cell fusion was confirmed by the Cre-lox strategy. Thus, hCSCs can be isolated and expanded in vitro for subsequent autologous regeneration of dead myocardium in patients affected by heart failure of ischemic and nonischemic origin. PMID:17709737

  15. The TEA CO2-Lasers with High Output Emission Intensity

    NASA Astrophysics Data System (ADS)

    Panchenko, Yu. N.; Losev, V. F.; Puchikin, А. V.; Jun, Yao

    2014-03-01

    TEA CO2-lasers generating short pulse radiation and operating in a pulse-periodic mode with the repetition rate up to 10 Hz have been developed. It is shown that the addition of nitrogen up to 8% in the mixture of molecular gases СО2:H2 = 500:50 at a total pressure of P = 0.6 bar enhances the peak emission power maintaining the temporary pulse shape. An output beam intensity of 12.3 MW/cm2 was obtained for the 30 ns pulse at a laser efficiency of 2.8%. In a compact TEA СО2-laser with an active medium volume of 6 cm3, a beam with an output intensity of 24 MW/cm2 at pulse duration of 70 ns was obtained.

  16. Light-operated proximity detector with linear output

    DOEpatents

    Simpson, M.L.; McNeilly, D.R.

    1984-01-01

    A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phtotransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

  17. Light-operated proximity detector with linear output

    DOEpatents

    Simpson, Marc L.; McNeilly, David R.

    1985-01-01

    A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phototransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

  18. Penetrating cardiac injuries.

    PubMed

    Mittal, V; McAleese, P; Young, S; Cohen, M

    1999-05-01

    Our objective was to determine the influence of several clinical factors on the survival of patients with penetrating wounds to the heart. A retrospective review of 80 consecutive penetrating cardiac injuries treated in a Level II urban trauma center from 1980 through 1994 were examined. Thirty-six patients (45%) had gunshot wounds (including 1 shotgun wound), and 44 (55%) had stab wounds. Intervention consisted of emergency room (ER) or operating room thoracotomy. We measured the effect of several clinical factors on morbidity and patient survival. Survival rate was 17 of 36 (47%) in gunshot injuries and 35 of 44 (80%) in stab injuries, with an overall survival rate of 52 of 80 patients (65%). The average age was 24 years (range, 9-53), and there were 3 female patients. Twelve patients (15%) had multiple cardiac injuries, and 63 (79%) had other associated injuries. Fourteen patients (17%) presented with no blood pressure, and 55 (69%) were hypotensive on admission. ER thoracotomy was performed on 7 of 52 survivors (13%) and 24 of 28 nonsurvivors (86%). Survival after ER thoracotomy was 7 of 31 patients (22%). A selective approach is recommended, because ER thoracotomy has a limited role in penetrating cardiac injury. A high index of suspicion, prompt resuscitation, and immediate definitive surgical management resulted in a high survival rate for these frequently lethal injuries. PMID:10231214

  19. Output tracking of some class non-minimum phase nonlinear systems via output redefinition

    NASA Astrophysics Data System (ADS)

    Firman, Naiborhu, Janson

    2016-02-01

    In this paper, we present the output tracking for a class non-minimum phase nonlinear. To achive the output tracking, we will apply the modified steepest descent control. To apply the modified steepest descent control, the output of the system will be redefined such that the system will become minimum phase with respect to a new output.

  20. Cardiac Emergencies in Neurosurgical Patients

    PubMed Central

    Petropolis, Andrea; Cappellani, Ronald B.

    2015-01-01

    Perioperative safety concerns are a major area of interest in recent years. Severe cardiac perturbation such as cardiac arrest is one of the most dreaded complications in the intraoperative period; however, little is known about the management of these events in the patients undergoing elective neurosurgery. This special group needs further attention, as it is often neither feasible nor appropriate to apply conventional advanced cardiac life support algorithms in patients undergoing neurosurgery. Factors such as neurosurgical procedure and positioning can also have a significant effect on the occurrence of cardiac arrest. Therefore, the aim of this paper is to describe the various causes and management of cardiac emergencies with special reference to cardiac arrest during elective neurosurgical procedures, including discussion of position-related factors and resuscitative considerations in these situations. This will help to formulate possible guidelines for management of such events. PMID:25692145

  1. Salacia oblonga root improves cardiac lipid metabolism in Zucker diabetic fatty rats: Modulation of cardiac PPAR-{alpha}-mediated transcription of fatty acid metabolic genes

    SciTech Connect

    Huang, Tom H.-W.; Yang Qinglin; Harada, Masaki; Uberai, Jasna; Radford, Jane; Li, George Q.; Yamahara, Johji; Roufogalis, Basil D.; Li Yuhao . E-mail: yuhao@pharm.usyd.edu.au

    2006-01-15

    Excess cardiac triglyceride accumulation in diabetes and obesity induces lipotoxicity, which predisposes the myocytes to death. On the other hand, increased cardiac fatty acid (FA) oxidation plays a role in the development of myocardial dysfunction in diabetes. PPAR-{alpha} plays an important role in maintaining homeostasis of lipid metabolism. We have previously demonstrated that the extract from Salacia oblonga root (SOE), an Ayurvedic anti-diabetic and anti-obesity medicine, improves hyperlipidemia in Zucker diabetic fatty (ZDF) rats (a genetic model of type 2 diabetes and obesity) and possesses PPAR-{alpha} activating properties. Here we demonstrate that chronic oral administration of SOE reduces cardiac triglyceride and FA contents and decreases the Oil red O-stained area in the myocardium of ZDF rats, which parallels the effects on plasma triglyceride and FA levels. Furthermore, the treatment suppressed cardiac overexpression of both FA transporter protein-1 mRNA and protein in ZDF rats, suggesting inhibition of increased cardiac FA uptake as the basis for decreased cardiac FA levels. Additionally, the treatment also inhibited overexpression in ZDF rat heart of PPAR-{alpha} mRNA and protein and carnitine palmitoyltransferase-1, acyl-CoA oxidase and 5'-AMP-activated protein kinase mRNAs and restored the downregulated acetyl-CoA carboxylase mRNA. These results suggest that SOE inhibits cardiac FA oxidation in ZDF rats. Thus, our findings suggest that improvement by SOE of excess cardiac lipid accumulation and increased cardiac FA oxidation in diabetes and obesity occurs by reduction of cardiac FA uptake, thereby modulating cardiac PPAR-{alpha}-mediated FA metabolic gene transcription.

  2. Output Control Using Feedforward And Cascade Controllers

    NASA Technical Reports Server (NTRS)

    Seraji, Homayoun

    1990-01-01

    Report presents theoretical study of open-loop control elements in single-input, single-output linear system. Focus on output-control (servomechanism) problem, in which objective is to find control scheme that causes output to track certain command inputs and to reject certain disturbance inputs in steady state. Report closes with brief discussion of characteristics and relative merits of feedforward, cascade, and feedback controllers and combinations thereof.

  3. Registry of Unexplained Cardiac Arrest

    ClinicalTrials.gov

    2015-04-13

    Cardiac Arrest; Long QT Syndrome; Brugada Syndrome; Catecholaminergi Polymorphic Ventricular Tachycardia; Idiopathic VentricularFibrillation; Early Repolarization Syndrome; Arrhythmogenic Right Ventricular Cardiomyopathy

  4. Epigenetic factors and cardiac development

    PubMed Central

    van Weerd, Jan Hendrick; Koshiba-Takeuchi, Kazuko; Kwon, Chulan; Takeuchi, Jun K.

    2011-01-01

    Congenital heart malformations remain the leading cause of death related to birth defects. Recent advances in developmental and regenerative cardiology have shed light on a mechanistic understanding of heart development that is controlled by a transcriptional network of genetic and epigenetic factors. This article reviews the roles of chromatin remodelling factors important for cardiac development with the current knowledge of cardiac morphogenesis, regeneration, and direct cardiac differentiation. In the last 5 years, critical roles of epigenetic factors have been revealed in the cardiac research field. PMID:21606181

  5. CMR Features in Cardiac Sarcoidosis.

    PubMed

    Prasher, Sparsh; Lee, Phong T; Dweck, Marc; Payne, John R

    2011-01-01

    Sarcoidosis is a multisystemic disorder of unknown aetiology characterised by the formation of noncaseating epithelioid cell granuloma involving various organ systems. Cardiac involvement has an important prognostic factor as it can present with life-threatening arrythmias and sudden death. Here, we present a case of cardiac sarcoidosis in a 46-year-old gentleman who presented with nonspecific signs and symptoms. We also discuss diagnostic difficulties especially when cardiac involvement is the only clinical sign. In this case, cardiac magnetic resonance (CMR) played an important role in the diagnosis and followup of our patient. PMID:22606556

  6. Cointegration of output, capital, labor, and energy

    NASA Astrophysics Data System (ADS)

    Stresing, R.; Lindenberger, D.; Kmmel, R.

    2008-11-01

    Cointegration analysis is applied to the linear combinations of the time series of (the logarithms of) output, capital, labor, and energy for Germany, Japan, and the USA since 1960. The computed cointegration vectors represent the output elasticities of the aggregate energy-dependent Cobb-Douglas function. The output elasticities give the economic weights of the production factors capital, labor, and energy. We find that they are for labor much smaller and for energy much larger than the cost shares of these factors. In standard economic theory output elasticities equal cost shares. Our heterodox findings support results obtained with LINEX production functions.

  7. Inaccurate calculation of drug output from nebulisers.

    PubMed

    O'Callaghan, C; Clarke, A R; Milner, A D

    1989-02-01

    A multistage liquid impinger was used to collect the nebulised cloud from three separate nebulisers. The output of sodium cromoglycate collected was determined by a spectrophotometric assay. Estimating drug output purely from weight loss during nebulisation resulted in a considerable overestimate compared with direct assay of the drug output from the nebulised cloud. During nebulisation, weight loss from the nebuliser occurs in the form of particle formation and also by evaporation. By only weighing the nebuliser chamber before and after nebulisation, weight loss due to evaporation is not taken into account and this is the cause of the overestimation of drug output by this method. PMID:2493380

  8. Access flow reduction for cardiac failure.

    PubMed

    Bourquelot, Pierre

    2016-03-01

    High-flow in hemodialysis arteriovenous angioaccesses is frequent. It may result in high-output cardiac failure, which should be prevented by fistula flow reduction. The most frequently reported flow reduction procedure is banding but immediate and long-term results are questionable. Alternative techniques are related here with personal results. Juxta-anastomosis "Proximal Radial Artery Ligation" (PRAL) is a very simple and effective reduction technique for side-to-end radio-cephalic fistulas (82 patients; reduction rate [RR]: 54% ± 19%). For brachial artery-based fistulas flow reduction two variants of Revision Using Distal Inflow (RUDI) procedures are used: 1) RUDI-1 using a polytetrafluoroethylene (PTFE) graft or a greater saphenous vein, which we first described in 1989 as "Distal Report of the Arterial Inflow" (35 patients; RR: 53% ± 18%), 2) RUDI-2 procedure, "Transposition of the Radial Artery", which we described in 2009 (47 patients; RR: 66% ± 14%). PMID:26951907

  9. Topical minoxidil: cardiac effects in bald man.

    PubMed Central

    Leenen, F H; Smith, D L; Unger, W P

    1988-01-01

    Systemic cardiovascular effects during chronic treatment with topical minoxidil vs placebo were evaluated using a double-blind, randomized design for two parallel groups (n = 20 for minoxidil, n = 15 for placebo). During 6 months of follow-up, blood pressure did not change, whereas minoxidil increased heart rate by 3-5 beats min-1. Compared with placebo, topical minoxidil caused significant increases in LV end-diastolic volume, in cardiac output (by 0.751 min-1) and in LV mass (by 5 g m-2). We conclude that in healthy subjects short-term use of topical minoxidil is likely not to be detrimental. However, safety needs to be established regarding ischaemic symptoms in patients with coronary artery disease as well as for the possible development of LV hypertrophy in healthy subjects during years of therapy. PMID:3191000

  10. How Is Sudden Cardiac Arrest Diagnosed?

    MedlinePlus

    ... the structure and function of the heart. Cardiac Catheterization Cardiac catheterization is a procedure used to diagnose and treat ... Study For an electrophysiology study, doctors use cardiac catheterization to record how your heart's electrical system responds ...

  11. Silicon central pattern generators for cardiac diseases

    PubMed Central

    Nogaret, Alain; O'Callaghan, Erin L; Lataro, Renata M; Salgado, Helio C; Meliza, C Daniel; Duncan, Edward; Abarbanel, Henry D I; Paton, Julian F R

    2015-01-01

    Cardiac rhythm management devices provide therapies for both arrhythmias and resynchronisation but not heart failure, which affects millions of patients worldwide. This paper reviews recent advances in biophysics and mathematical engineering that provide a novel technological platform for addressing heart disease and enabling beat-to-beat adaptation of cardiac pacing in response to physiological feedback. The technology consists of silicon hardware central pattern generators (hCPGs) that may be trained to emulate accurately the dynamical response of biological central pattern generators (bCPGs). We discuss the limitations of present CPGs and appraise the advantages of analog over digital circuits for application in bioelectronic medicine. To test the system, we have focused on the cardio-respiratory oscillators in the medulla oblongata that modulate heart rate in phase with respiration to induce respiratory sinus arrhythmia (RSA). We describe here a novel, scalable hCPG comprising physiologically realistic (Hodgkin–Huxley type) neurones and synapses. Our hCPG comprises two neurones that antagonise each other to provide rhythmic motor drive to the vagus nerve to slow the heart. We show how recent advances in modelling allow the motor output to adapt to physiological feedback such as respiration. In rats, we report on the restoration of RSA using an hCPG that receives diaphragmatic electromyography input and use it to stimulate the vagus nerve at specific time points of the respiratory cycle to slow the heart rate. We have validated the adaptation of stimulation to alterations in respiratory rate. We demonstrate that the hCPG is tuneable in terms of the depth and timing of the RSA relative to respiratory phase. These pioneering studies will now permit an analysis of the physiological role of RSA as well as its any potential therapeutic use in cardiac disease. PMID:25433077

  12. Silicon central pattern generators for cardiac diseases.

    PubMed

    Nogaret, Alain; O'Callaghan, Erin L; Lataro, Renata M; Salgado, Helio C; Meliza, C Daniel; Duncan, Edward; Abarbanel, Henry D I; Paton, Julian F R

    2015-02-15

    Cardiac rhythm management devices provide therapies for both arrhythmias and resynchronisation but not heart failure, which affects millions of patients worldwide. This paper reviews recent advances in biophysics and mathematical engineering that provide a novel technological platform for addressing heart disease and enabling beat-to-beat adaptation of cardiac pacing in response to physiological feedback. The technology consists of silicon hardware central pattern generators (hCPGs) that may be trained to emulate accurately the dynamical response of biological central pattern generators (bCPGs). We discuss the limitations of present CPGs and appraise the advantages of analog over digital circuits for application in bioelectronic medicine. To test the system, we have focused on the cardio-respiratory oscillators in the medulla oblongata that modulate heart rate in phase with respiration to induce respiratory sinus arrhythmia (RSA). We describe here a novel, scalable hCPG comprising physiologically realistic (Hodgkin-Huxley type) neurones and synapses. Our hCPG comprises two neurones that antagonise each other to provide rhythmic motor drive to the vagus nerve to slow the heart. We show how recent advances in modelling allow the motor output to adapt to physiological feedback such as respiration. In rats, we report on the restoration of RSA using an hCPG that receives diaphragmatic electromyography input and use it to stimulate the vagus nerve at specific time points of the respiratory cycle to slow the heart rate. We have validated the adaptation of stimulation to alterations in respiratory rate. We demonstrate that the hCPG is tuneable in terms of the depth and timing of the RSA relative to respiratory phase. These pioneering studies will now permit an analysis of the physiological role of RSA as well as its any potential therapeutic use in cardiac disease. PMID:25433077

  13. Cell-Specific Cardiac Electrophysiology Models

    PubMed Central

    Groenendaal, Willemijn; Ortega, Francis A.; Kherlopian, Armen R.; Zygmunt, Andrew C.; Krogh-Madsen, Trine; Christini, David J.

    2015-01-01

    The traditional cardiac model-building paradigm involves constructing a composite model using data collected from many cells. Equations are derived for each relevant cellular component (e.g., ion channel, exchanger) independently. After the equations for all components are combined to form the composite model, a subset of parameters is tuned, often arbitrarily and by hand, until the model output matches a target objective, such as an action potential. Unfortunately, such models often fail to accurately simulate behavior that is dynamically dissimilar (e.g., arrhythmia) to the simple target objective to which the model was fit. In this study, we develop a new approach in which data are collected via a series of complex electrophysiology protocols from single cardiac myocytes and then used to tune model parameters via a parallel fitting method known as a genetic algorithm (GA). The dynamical complexity of the electrophysiological data, which can only be fit by an automated method such as a GA, leads to more accurately parameterized models that can simulate rich cardiac dynamics. The feasibility of the method is first validated computationally, after which it is used to develop models of isolated guinea pig ventricular myocytes that simulate the electrophysiological dynamics significantly better than does a standard guinea pig model. In addition to improving model fidelity generally, this approach can be used to generate a cell-specific model. By so doing, the approach may be useful in applications ranging from studying the implications of cell-to-cell variability to the prediction of intersubject differences in response to pharmacological treatment. PMID:25928268

  14. Designing for Maintainability and System Availability

    NASA Technical Reports Server (NTRS)

    Lalli, Vincent R.; Packard, Michael H.

    1997-01-01

    The final goal for a delivered system (whether a car, aircraft, avionics box or computer) should be its availability to operate and perform its intended function over its expected design life. Hence, in designing a system, we cannot think in terms of delivering the system and just walking away. The system supplier needs to provide support throughout the operating life of the product. Here, supportability requires an effective combination of reliability, maintainability, logistics and operations engineering (as well as safety engineering) to have a system that is available for its intended use throughout its designated mission lifetime. Maintainability is a key driving element in the effective support and upkeep of the system as well as providing the ability to modify and upgrade the system throughout its lifetime. This paper then, will concentrate on maintainability and its integration into the system engineering and design process. The topics to be covered include elements of maintainability, the total cost of ownership, how system availability, maintenance and logistics costs and spare parts cost effect the overall program costs. System analysis and maintainability will show how maintainability fits into the overall systems approach to project development. Maintainability processes and documents will focus on how maintainability is to be performed and what documents are typically generated for a large scale program. Maintainability analysis shows how trade-offs can be performed for various alternative components. The conclusions summarize the paper and are followed by specific problems for hands-on training.

  15. X-ray source assembly having enhanced output stability, and fluid stream analysis applications thereof

    DOEpatents

    Radley, Ian; Bievenue, Thomas J.; Burdett Jr., John H.; Gallagher, Brian W.; Shakshober, Stuart M.; Chen, Zewu; Moore, Michael D.

    2007-04-24

    An x-ray source assembly (2700) and method of operation are provided having enhanced output stability. The assembly includes an anode (2125) having a source spot upon which electrons (2120) impinge and a control system (2715/2720) for controlling position of the anode source spot relative to an output structure. The control system can maintain the anode source spot location relative to the output structure (2710) notwithstanding a change in one or more operating conditions of the x-ray source assembly. One aspect of the disclosed invention is most amenable to the analysis of sulfur in petroleum-based fuels.

  16. X-ray source assembly having enhanced output stability, and fluid stream analysis applications thereof

    DOEpatents

    Radley, Ian; Bievenue, Thomas J.; Burdett, John H.; Gallagher, Brian W.; Shakshober, Stuart M.; Chen, Zewu; Moore, Michael D.

    2008-06-08

    An x-ray source assembly and method of operation are provided having enhanced output stability. The assembly includes an anode having a source spot upon which electrons impinge and a control system for controlling position of the anode source spot relative to an output structure. The control system can maintain the anode source spot location relative to the output structure notwithstanding a change in one or more operating conditions of the x-ray source assembly. One aspect of the disclosed invention is most amenable to the analysis of sulfur in petroleum-based fuels.

  17. Investigating data envelopment analysis model with potential improvement for integer output values

    NASA Astrophysics Data System (ADS)

    Hussain, Mushtaq Taleb; Ramli, Razamin; Khalid, Ruzelan

    2015-12-01

    The decrement of input proportions in DEA model is associated with its input reduction. This reduction is apparently good for economy since it could reduce unnecessary cost resources. However, in some situations the reduction of relevant inputs such as labour could create social problems. Such inputs should thus be maintained or increased. This paper develops an advanced radial DEA model dealing with mixed integer linear programming to improve integer output values through the combination of inputs. The model can deal with real input values and integer output values. This model is valuable for situations dealing with input combination to improve integer output values as faced by most organizations.

  18. Non‐random fluctuations in power output during self‐paced exercise

    PubMed Central

    Tucker, R; Bester, A; Lambert, E V; Noakes, T D; Vaughan, C L; Gibson, A St Clair

    2006-01-01

    Objectives To analyse the power output measured during a self‐paced 20‐km cycling time trial, during which power output was free to vary, in order to assess the level and characteristics of the variability in power output that occurred during the exercise bout. Methods Eleven well‐trained cyclists performed a 20‐km cycling time trial, during which power output was sampled every 200 m. Power spectrum analysis was performed on the power output data, and a fractal dimension was calculated for each trial using the Higuchi method. Results In all subjects, power output was maintained throughout the trial until the final kilometre, when it increased significantly, indicating the presence of a global pacing strategy. The power spectrum revealed the presence of 1/f‐like scaling of power output and multiple frequency peaks during each trial, with the values of the frequency peaks changing over the course of the trial. The fractal dimension (D‐score) was similar for all subjects over the 20‐km trial and ranged between 1.5 and 1.9. Conclusions The presence of an end spurt in all subjects, 1/f‐like scaling and multiple frequency peaks in the power output data indicate that the measured oscillations in power output during cycling exercise activity may not be system noise, but may rather be associated with system control mechanisms that are similar in different individuals. PMID:16980537

  19. Are older patients’ cardiac rehabilitation needs being met?

    PubMed Central

    Tolmie, Elizabeth P; Lindsay, Grace M; Kelly, Tim; Tolson, Debbie; Baxter, Susan; Belcher, Philip R

    2009-01-01

    Aims. The primary aim of this study was to examine the needs of older people in relation to cardiac rehabilitation and to determine if these were currently being met. A secondary aim was to compare illness representations, quality of life and anxiety and depression in groups with different levels of attendance at a cardiac rehabilitation programme. Background. Coronary heart disease accounted for over seven million cardiovascular deaths globally in 2001. Associated deaths increase with age and are highest in those older than 65. Effective cardiac rehabilitation can assist independent function and maintain health but programme uptake rates are low. We have, therefore, focussed specifically on the older patient to determine reasons for the low uptake. Design. Mixed methods. Methods. A purposive sample of 31 older men and women (≥65 years) completed three questionnaires to determine illness representations, quality of life and anxiety and depression. They then underwent a brief clinical assessment and participated in a face-to-face audio-taped interview. Results. Quantitative: Older adults, who did not attend a cardiac rehabilitation programme, had significantly poorer personal control and depression scores (p < 0·01) and lower quality of life scores than those who had attended. Few achieved recommended risk factor reduction targets. Qualitative: The three main themes identified as reflecting the views and experiences of and attendance at the cardiac rehabilitation programme were: ‘The sensible thing to do’, ‘Assessing the impact’ and ‘Nothing to gain’. Conclusions. Irrespective of level of attendance, cardiac rehabilitation programmes are not meeting the needs of many older people either in terms of risk factor reduction or programme uptake. More appropriate programmes are needed. Relevance to clinical practice. Cardiac rehabilitation nurses are ideally placed to identify the rehabilitation needs of older people. Identifying these from the older person’s perspective could help guide more appropriate intervention strategies. PMID:19638048

  20. Cardiac myosin binding protein C regulates postnatal myocyte cytokinesis

    PubMed Central

    Jiang, Jianming; Burgon, Patrick G.; Wakimoto, Hiroko; Onoue, Kenji; Gorham, Joshua M.; O’Meara, Caitlin C.; Fomovsky, Gregory; McConnell, Bradley K.; Lee, Richard T.; Seidman, J. G.; Seidman, Christine E.

    2015-01-01

    Homozygous cardiac myosin binding protein C-deficient (Mybpct/t) mice develop dramatic cardiac dilation shortly after birth; heart size increases almost twofold. We have investigated the mechanism of cardiac enlargement in these hearts. Throughout embryogenesis myocytes undergo cell division while maintaining the capacity to pump blood by rapidly disassembling and reforming myofibrillar components of the sarcomere throughout cell cycle progression. Shortly after birth, myocyte cell division ceases. Cardiac MYBPC is a thick filament protein that regulates sarcomere organization and rigidity. We demonstrate that many Mybpct/t myocytes undergo an additional round of cell division within 10 d postbirth compared with their wild-type counterparts, leading to increased numbers of mononuclear myocytes. Short-hairpin RNA knockdown of Mybpc3 mRNA in wild-type mice similarly extended the postnatal window of myocyte proliferation. However, adult Mybpct/t myocytes are unable to fully regenerate the myocardium after injury. MYBPC has unexpected inhibitory functions during postnatal myocyte cytokinesis and cell cycle progression. We suggest that human patients with homozygous MYBPC3-null mutations develop dilated cardiomyopathy, coupled with myocyte hyperplasia (increased cell number), as observed in Mybpct/t mice. Human patients, with heterozygous truncating MYBPC3 mutations, like mice with similar mutations, have hypertrophic cardiomyopathy. However, the mechanism leading to hypertrophic cardiomyopathy in heterozygous MYBPC3+/− individuals is myocyte hypertrophy (increased cell size), whereas the mechanism leading to cardiac dilation in homozygous Mybpc3−/− mice is primarily myocyte hyperplasia. PMID:26153423

  1. Hierarchical Approaches for Systems Modeling in Cardiac Development

    PubMed Central

    Gould, Russell A.; Aboulmouna, Lina M.; Varner, Jeffrey D.; Butcher, Jonathan T.

    2013-01-01

    Ordered cardiac morphogenesis and function is essential for all vertebrate life. The heart begins as a simple contractile tube, but quickly grows and morphs into a multi-chambered pumping organ, complete with valves, while maintaining regulation of blood flow and nutrient distribution. Though not identical, cardiac morphogenesis shares many molecular and morphological processes across vertebrate species. Quantitative data across multiple time and length scales have been gathered through decades of reductionist single variable analyses. These range from detailed molecular signaling pathways at the cellular levels to cardiac function at the tissue/organ levels. However, none of these components act in true isolation from others, and each, in turn, exhibits short- and long-range effects in both time and space. With the absence of a gene, entire signaling cascades and genetic profiles may be shifted, resulting in complex feedback mechanisms. Also taking into account local microenvironmental changes throughout development, it is apparent that a systems level approach is an essential resource to accelerate information generation concerning the functional relationships across multiple length scales (molecular data vs. physiological function) and structural development. In this review, we discuss relevant in vivo and in vitro experimental approaches, compare different computational frameworks for systems modeling, and the latest information about systems modeling of cardiac development. Lastly, we conclude with some important future directions for cardiac systems modeling. PMID:23463736

  2. Amino acids as metabolic substrates during cardiac ischemia.

    PubMed

    Drake, Kenneth J; Sidorov, Veniamin Y; McGuinness, Owen P; Wasserman, David H; Wikswo, John P

    2012-12-01

    The heart is well known as a metabolic omnivore in that it is capable of consuming fatty acids, glucose, ketone bodies, pyruvate, lactate, amino acids and even its own constituent proteins, in order of decreasing preference. The energy from these substrates supports not only mechanical contraction, but also the various transmembrane pumps and transporters required for ionic homeostasis, electrical activity, metabolism and catabolism. Cardiac ischemia - for example, due to compromise of the coronary vasculature or end-stage heart failure - will alter both electrical and metabolic activity. While the effects of myocardial ischemia on electrical propagation and stability have been studied in depth, the effects of ischemia on metabolic substrate preference has not been fully appreciated: oxygen deprivation during ischemia will significantly alter the relative ability of the heart to utilize each of these substrates. Although changes in cardiac metabolism are understood to be an underlying component in almost all cardiac myopathies, the potential contribution of amino acids in maintaining cardiac electrical conductance and stability during ischemia is underappreciated. Despite clear evidence that amino acids exert cardioprotective effects in ischemia and other cardiac disorders, their role in the metabolism of the ischemic heart has yet to be fully elucidated. This review synthesizes the current literature of the metabolic contribution of amino acids during ischemia by analyzing relevant historical and recent research. PMID:23354395

  3. Tissue Oxygenation Response to Mild Hypercapnia during Cardiopulmonary Bypass with Constant Pump Output

    PubMed Central

    Akça, Ozan; Sessler, Daniel I; DeLong, Diane; Keijner, Raymond; Ganzel, Brian; Doufas, Anthony G

    2006-01-01

    Background Tissue oxygenation is the primary determinant of wound infection risk. Mild hypercapnia markedly improves cutaneous, subcutaneous, and muscular tissue oxygenation in volunteers and patients. However, relative contributions of increased cardiac output and peripheral vasodilation to this response remains unknown. We thus tested the hypothesis that increased cardiac output is the dominant mechanism. Methods We recruited 10 ASA III patients, aged 40–65 years, undergoing cardiopulmonary bypass for this crossover trial. After induction of anaesthesia, a Silastic tonometer was inserted subcutaneously in the upper arm. Subcutaneous tissue oxygen tension was measured with both polarographic electrode and fluorescence-based systems. Oximeter probes were placed bilaterally on the forehead to monitor cerebral oxygenation. After initiation of cardiopulmonary bypass, in random order patients were exposed to two arterial CO2 partial pressures for 30 minutes each: 35 (normocapnia) or 50 mmHg (hypercapnia). Bypass pump flow was kept constant throughout the measurement periods. Results Hypercapnia during bypass had essentially no effect on PaO2, mean arterial pressure, or tissue temperature. PaCO2 and pH differed significantly. Subcutaneous tissue oxygenation was virtually identical during the two PaCO2 periods (139 [50,163] vs. 145 [38,158], P=0.335) (median [range]). In contrast, cerebral oxygen saturation (our positive control measurement) was significantly less during normocapnia (57 [28,67]%) than hypercapnia (64 [37,89]%, P=0.025). Conclusions Mild hypercapnia, which normally markedly increases tissue oxygenation, did not do so during cardiopulmonary bypass with fixed pump output. This suggests that hypercapnia normally increases tissue oxygenation by increasing cardiac output rather than direct dilation of peripheral vessels. PMID:16675511

  4. Capillary force lithography for cardiac tissue engineering.

    PubMed

    Macadangdang, Jesse; Lee, Hyun Jung; Carson, Daniel; Jiao, Alex; Fugate, James; Pabon, Lil; Regnier, Michael; Murry, Charles; Kim, Deok-Ho

    2014-01-01

    Cardiovascular disease remains the leading cause of death worldwide(1). Cardiac tissue engineering holds much promise to deliver groundbreaking medical discoveries with the aims of developing functional tissues for cardiac regeneration as well as in vitro screening assays. However, the ability to create high-fidelity models of heart tissue has proven difficult. The heart's extracellular matrix (ECM) is a complex structure consisting of both biochemical and biomechanical signals ranging from the micro- to the nanometer scale(2). Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering(3-5). A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling(2). Unfortunately, few methods have been able to mimic the organization of ECM fibers down to the nanometer scale. Recent advancements in nanofabrication techniques, however, have enabled the design and fabrication of scalable scaffolds that mimic the in vivo structural and substrate stiffness cues of the ECM in the heart(6-9). Here we present the development of two reproducible, cost-effective, and scalable nanopatterning processes for the functional alignment of cardiac cells using the biocompatible polymer poly(lactide-co-glycolide) (PLGA)(8) and a polyurethane (PU) based polymer. These anisotropically nanofabricated substrata (ANFS) mimic the underlying ECM of well-organized, aligned tissues and can be used to investigate the role of nanotopography on cell morphology and function(10-14). Using a nanopatterned (NP) silicon master as a template, a polyurethane acrylate (PUA) mold is fabricated. This PUA mold is then used to pattern the PU or PLGA hydrogel via UV-assisted or solvent-mediated capillary force lithography (CFL), respectively(15,16). Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip and the PUA mold is placed on top. For UV-assisted CFL, the PU is then exposed to UV radiation (λ = 250-400 nm) for curing. For solvent-mediated CFL, the PLGA is embossed using heat (120 °C) and pressure (100 kPa). After curing, the PUA mold is peeled off, leaving behind an ANFS for cell culture. Primary cells, such as neonatal rat ventricular myocytes, as well as human pluripotent stem cell-derived cardiomyocytes, can be maintained on the ANFS(2). PMID:24962161

  5. Reinvestigating the Noticing Function of Output

    ERIC Educational Resources Information Center

    Uggen, Maren S.

    2012-01-01

    A conceptual replication of Izumi and Bigelow's research, this study used multiple measures to investigate second language (L2) learners' processes in output-input-output sequences. Specifically, it examined whether producing the target language impacts learners' attention to L2 structures in subsequent input. Thirty learners of English as a…

  6. High Power Amplifier Harmonic Output Level Measurement

    NASA Technical Reports Server (NTRS)

    Perez, R. M.; Hoppe, D. J.; Khan, A. R.

    1995-01-01

    A method is presented for the measurement of the harmonic output power of high power klystron amplifiers, involving coherent hemispherical radiation pattern measurements of the radiated klystron output. Results are discussed for the operation in saturated and unsaturated conditions, and with a waveguide harmonic filter included.

  7. DIST/AVC Out-Put Definition.

    ERIC Educational Resources Information Center

    Wilkinson, Gene L.

    The first stage of development of a management information system for DIST/AVC (Division of Instructional Technology/Audio-Visual Center) is the definition of out-put units. Some constraints on the definition of output units are: 1) they should reflect goals of the organization, 2) they should reflect organizational structure and procedures, and…

  8. Power output measurement during treadmill cycling.

    PubMed

    Coleman, D A; Wiles, J D; Davison, R C R; Smith, M F; Swaine, I L

    2007-06-01

    The study aim was to consider the use of a motorised treadmill as a cycling ergometry system by assessing predicted and recorded power output values during treadmill cycling. Fourteen male cyclists completed repeated cycling trials on a motorised treadmill whilst riding their own bicycle fitted with a mobile ergometer. The speed, gradient and loading via an external pulley system were recorded during 20-s constant speed trials and used to estimate power output with an assumption about the contribution of rolling resistance. These values were then compared with mobile ergometer measurements. To assess the reliability of measured power output values, four repeated trials were conducted on each cyclist. During level cycling, the recorded power output was 257.2 +/- 99.3 W compared to the predicted power output of 258.2 +/- 99.9 W (p > 0.05). For graded cycling, there was no significant difference between measured and predicted power output, 268.8 +/- 109.8 W vs. 270.1 +/- 111.7 W, p > 0.05, SEE 1.2 %. The coefficient of variation for mobile ergometer power output measurements during repeated trials ranged from 1.5 % (95 % CI 1.2 - 2.0 %) to 1.8 % (95 % CI 1.5 - 2.4 %). These results indicate that treadmill cycling can be used as an ergometry system to assess power output in cyclists with acceptable accuracy. PMID:17497583

  9. Computer output to RDD-1 plotter

    SciTech Connect

    Solnvshkin, S.D.; Chikhman, V.N.

    1986-03-01

    Hardware and software for data output from a CAMAC-interfaced SM-4 computer to an RDD-1 plotter are described. A type-350 ''Output Register'' module is used for communication of the RDD-1 with the CAMAC dataway. The graphics software is written in Macro for a RAFOS operating system.

  10. Computer Output Microfilm and Library Catalogs.

    ERIC Educational Resources Information Center

    Meyer, Richard W.

    Early computers dealt with mathematical and scientific problems requiring very little input and not much output, therefore high speed printing devices were not required. Today with increased variety of use, high speed printing is necessary and Computer Output Microfilm (COM) devices have been created to meet this need. This indirect process can…

  11. Laser wavelength selector and output coupler

    NASA Technical Reports Server (NTRS)

    Hard, T. M.

    1970-01-01

    Optical system eliminates displacement occurring when wavelengths are selected in multiple wavelength laser utilizing intracavity wavelength selection by first-order Littrow reflection of plane grating. Output coupling varies direction of output beam as different wavelengths are selected by grating rotation.

  12. Maintaining and Enhancing a College or University Image. AIR Forum 1982 Paper.

    ERIC Educational Resources Information Center

    Fram, Eugene H.

    The use of marketing concepts to maintain and enhance the image of a university is considered. Over all, what is needed is a system for image assessment to provide a basis for image development. Without this system and its information outputs, misconceptions can enter the policy-making process at critical junctures, and the life of the institution…

  13. Short Duration Combined Mild Hypothermia Improves Resuscitation Outcomes in a Porcine Model of Prolonged Cardiac Arrest

    PubMed Central

    Yu, Tao; Yang, Zhengfei; Li, Heng; Ding, Youde; Huang, Zitong; Li, Yongqin

    2015-01-01

    Objective. In this study, our aim was to investigate the effects of combined hypothermia with short duration maintenance on the resuscitation outcomes in a porcine model of ventricular fibrillation (VF). Methods. Fourteen porcine models were electrically induced with VF and untreated for 11 mins. All animals were successfully resuscitated manually and then randomized into two groups: combined mild hypothermia (CH group) and normothermia group (NT group). A combined hypothermia of ice cold saline infusion and surface cooling was implemented in the animals of the CH group and maintained for 4 hours. The survival outcomes and neurological function were evaluated every 24 hours until a maximum of 96 hours. Neuron apoptosis in hippocampus was analyzed. Results. There were no significant differences in baseline physiologies and primary resuscitation outcomes between both groups. Obvious improvements of cardiac output were observed in the CH group at 120, 180, and 240 mins following resuscitation. The animals demonstrated better survival at 96 hours in the CH group when compared to the NT group. In comparison with the NT group, favorable neurological functions were observed in the CH group. Conclusion. Short duration combined cooling initiated after resuscitation improves survival and neurological outcomes in a porcine model of prolonged VF. PMID:26558261

  14. DISTRIBUTION OF CARDIAC OUTPUT DURING DIURNAL CHANGES IN ACTIVITY IN RATS

    EPA Science Inventory

    The hepatotoxicity of carbon tetrachloride and chloroform in rats is increased when exposure occurs during the dark part of the lighting cycle when rats are more active. ats are used as surrogates for humans in toxicology, but have opposite activity patterns, with humans being ac...

  15. Changes in cardiac output and tibial artery flow during and after progressive LBNP

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A 3.0 MHz Pulsed Doppler velocity meter (PD) was used to determine blood velocities in the ascending aorta from the suprasternal notch before, during and after progressive 5 min stages of lower body negative pressure (LBNP) in 7 subjects. Changes in stroke volume were calculated from the systolic velocity integrals. A unique 20 MHz PD was used to estimate bloodflow in the posterior tibial artery. With -20 torr mean stroke volume fell 11% and then continued to decline by 48% before LBNP was terminated. Mean tibial flow fell progressively with LBNP stress, due to an increase in reverse flow component and a reduction in peak forward flow and diameter. Stroke volume increased and heart rate fell dramatically during the first 15 sec of recovery. The LBNP was terminated early in 2 subjects because of vasovagal symptons (V). During V the stroke volume rose 86% which more than compensated for the drop in heart rate. This implies that V is accompanied by a paradoxical increase in venous return and that the reduction in HR is the primary cardiovascular event. During the first 15 sec of recovery these 2 subjects had a distinctive marked rise to heart rate reminiscent of the Bainbridge reflex.

  16. Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity

    NASA Technical Reports Server (NTRS)

    Verbanck, S.; Larsson, H.; Linnarsson, D.; Prisk, G. K.; West, J. B.; Paiva, M.

    1997-01-01

    In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P < 0.001). There was a concomittant reduction in stroke volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P < 0.05) late in flight. These findings suggest that, despite increased pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG.

  17. Measurement of acetylene in breath by ultraviolet absorption spectroscopy: Potential for noninvasive cardiac output monitoring

    NASA Astrophysics Data System (ADS)

    Baum, Marc M.; Kumar, Sasi; Lappas, Anastasios M.; Wagner, Peter D.

    2003-06-01

    A new, miniaturized, noninvasive instrument for rapid acetylene analysis in breath gas is described. Acetylene is a blood-soluble gas and for many years its uptake rate during rebreathing and/or nonrebreathing tests has been used to calculate the volume of lung tissue as well as the flow rate of blood through the lungs. The instrument relies on dispersive UV absorption spectroscopy as its measurement principle and is employed in an extractive (side-stream) configuration. The analyzer afforded fast (276±43 ms, 0%-90%, at 2 L min-1 flow rates), interference-free detection of acetylene, with signal-to-noise ratios in excess of 50. Comparison tests with a mass spectrometer using calibration gas samples gave an excellent correlation {[C2H2]MS=0.999. [C2H2]UV, R2=1.000}, which validated the linearity and accuracy of the UV system. A similar level of correlation between these devices also was observed during human subject C2H2 uptake tests, with both instruments sampling a common extracted gas stream {[C2H2]UV=0.940. [C2H2]MS, R2=0.998}. These results indicate that a miniature, low-cost, rugged, ultraviolet spectrometer system measuring acetylene holds promise for human breath analysis in a clinical setting.

  18. [Chronic surplus of Japanese cardiac surgeon--ideal nurse practitioner for cardiac surgery, cardiac surgeon's attitude toward the future].

    PubMed

    Ikegami, Hirohisa

    2014-03-01

    It is chronically surplus of doctors in the world of cardiac surgery. There are too many cardiac surgeons because cardiac surgery requires a large amount of manpower resources to provide adequate medical services. Many Japanese cardiac surgeons do not have enough opportunity to perform cardiac surgery operations, and many Japanese cardiac surgery residents do not have enough opportunity to learn cardiac surgery operations. There are physician assistants and nurse practitioners in the US. Because they provide a part of medical care to cardiac surgery patients, American cardiac surgeons can focus more energy on operative procedures. Introduction of cardiac surgery specialized nurse practitioner is essential to deliver a high quality medical service as well as to solve chronic problems that Japanese cardiac surgery has had for a long time. PMID:24749334

  19. Health Instruction Packages: Cardiac Anatomy.

    ERIC Educational Resources Information Center

    Phillips, Gwen; And Others

    Text, illustrations, and exercises are utilized in these five learning modules to instruct nurses, students, and other health care professionals in cardiac anatomy and functions and in fundamental electrocardiographic techniques. The first module, "Cardiac Anatomy and Physiology: A Review" by Gwen Phillips, teaches the learner to draw and label

  20. Health Instruction Packages: Cardiac Anatomy.

    ERIC Educational Resources Information Center

    Phillips, Gwen; And Others

    Text, illustrations, and exercises are utilized in these five learning modules to instruct nurses, students, and other health care professionals in cardiac anatomy and functions and in fundamental electrocardiographic techniques. The first module, "Cardiac Anatomy and Physiology: A Review" by Gwen Phillips, teaches the learner to draw and label…

  1. Genetic determinants of cardiac hypertrophy

    PubMed Central

    Marian, Ali J.

    2009-01-01

    Purpose of review Cardiac hypertrophy is a common phenotypic response of the heart to stimulants. It is associated with increased morbidity and mortality in various cardiovascular disorders. Genetic factors are important determinants of phenotypic expression of cardiac hypertrophy, whether in single-gene disorders or in complex traits. We focus on the molecular genetics of cardiac hypertrophy in various conditions with an emphasis on hypertrophic cardiomyopathy, a genetic paradigm of cardiac hypertrophic response. Recent findings The molecular genetic basis of cardiac hypertrophy in single-gene disorders has been partially elucidated. Likewise, the impact of genetics on the expression of cardiac hypertrophy in the general population has been demonstrated. Identification of mutations in the Z disk proteins has expanded the spectrum of causal mutations beyond the thin and thick filaments of the sarcomeres. In addition, modifier loci have been mapped and shown to impart considerable effects on the expression of cardiac hypertrophy in hypertrophic cardiomyopathy. Elucidation of the molecular genetics of sarcomeric hypertrophic cardiomyopathy and many of the phenocopies has highlighted the limitations of clinical diagnosis as a determinant of management and prognostic advice. The findings have raised the importance of diagnosis and treatment algorithms, which are based on both genotype and phenotype information. Summary Cardiac hypertrophy, regardless of the cause, is the phenotypic consequence of complex interactions between genetic and nongenetic factors. PMID:18382207

  2. [Hygienic handling in cardiac surgery].

    PubMed

    Shimasaki, T; Masaoka, T; Hirooka, S; Abe, H; Watanabe, T; Washio, M

    1993-04-01

    Some points regarding the hygienic handling in cardiac surgery are mentioned. The sternal infection or mediastinitis is still one of the most important complications after cardiac operation especially when ITA is used for CABG. After we paid much attention to these points, the postoperative sternal infection has decreased obviously. PMID:8468855

  3. Encapsulation method for maintaining biodecontamination activity

    DOEpatents

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

    2002-01-01

    A method for maintaining the viability and subsequent activity of microorganisms utilized in a variety of environments to promote biodecontamination of surfaces. One application involves the decontamination of concrete surfaces. Encapsulation of microbial influenced degradation (MID) microorganisms has shown that MID activity is effectively maintained under passive conditions, that is, without manual addition of moisture or nutrients, for an extended period of time.

  4. Encapsulation method for maintaining biodecontamination activity

    DOEpatents

    Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

    2006-04-11

    A method for maintaining the viability and subsequent activity of microorganisms utilized in a variety of environments to promote biodecontamination of surfaces. One application involves the decontamination of concrete surfaces. Encapsulation of microbial influenced degradation (MID) microorganisms has shown that MID activity is effectively maintained under passive conditions, that is, without manual addition of moisture or nutrients, for an extended period of time.

  5. Cardiac Dysfunction during Exercise in Uncomplicated Type 2 Diabetes

    PubMed Central

    REGENSTEINER, JUDITH G.; BAUER, TIMOTHY A.; REUSCH, JANE E. B.; QUAIFE, ROBERT A.; CHEN, MARCUS Y.; SMITH, SUSAN C.; MILLER, TYLER M.; GROVES, BERTRON M.; WOLFEL, EUGENE E.

    2010-01-01

    Purpose Type 2 diabetes mellitus (T2DM) has been associated with reduced peak exercise capacity (V̇O2peak). The causes of this impairment are not clearly established, but evidence suggests that abnormalities in cardiac function play a significant role. We hypothesized that exercise would be associated with impaired cardiac function and hemodynamics in recently diagnosed T2DM, even in the absence of clinically evident cardiovascular complications. Methods After baseline normal echocardiography screening, 10 premenopausal women with uncomplicated T2DM (average duration of diagnosed T2DM, 3.6 yr) and 10 healthy nondiabetic women of similar age, weight, and activity levels performed a peak cardiopulmonary exercise test while instrumented with an indwelling pulmonary artery catheter for assessing cardiac function. On separate days, technetium-99m sestamibi (cardolite) imaging was performed to assess myocardial perfusion at rest and peak exercise in seven T2DM and seven control patients. Results Resting measures of cardiac hemodynamics were similar in T2DM and control subjects. Absolute V̇O2peak (mL·min−1) and peak cardiac output (L·min−1) tended to be lower in T2DM than in control subjects but did not reach statistical significance. However, pulmonary capillary wedge pressure (PCWP) rose significantly more during exercise in T2DM than in controls (148% vs 109% increase at peak exercise, P < 0.01). Normalized myocardial perfusion index was lower in persons with diabetes than in controls (11.0 ± 3.5 × e−9 vs 17.5 ± 8.1 × e−9, respectively, P < 0.05) and inversely related to peak exercise PCWP (R = −0.56, P < 0.05). Conclusions Cardiac hemodynamics during graded exercise are altered in women with recently diagnosed T2DM as demonstrated by the disproportionate increase in PCWP at peak exercise compared with controls subjects. Cardiac abnormalities observed are potentially early signs of subclinical cardiac dysfunction associated with T2DM, which may precede the more greatly impaired cardiac function at rest and with exercise observed in longer established T2DM. PMID:19346991

  6. Cardiac Complications in Children With Human Immunodeficiency Virus Infection

    PubMed Central

    Starc, Thomas J.; Lipshultz, Steven E.; Kaplan, Samuel; Easley, Kirk A.; Bricker, J. Timothy; Colan, Steven D.; Lai, Wyman W.; Gersony, Welton M.; Sopko, George; Moodie, Douglas S.; Schluchter, Mark D.

    2015-01-01

    Objective Although numerous cardiac abnormalities have been reported in HIV-infected children, precise estimates of the incidence of cardiac disease in these children are not well-known. The objective of this report is to describe the 2-year cumulative incidence of cardiac abnormalities in HIV-infected children. Methodology: Design Prospective cohort (Group I) and inception cohort (Group II) study design. Setting A volunteer sample from 10 university and public hospitals. Participants Group I consisted of 205 HIV vertically infected children enrolled at a median age of 22 months. This group was comprised of infants and children already known to be HIV-infected at the time of enrollment in the study. Most of the children were African-American or Hispanic and 89% had symptomatic HIV infection at enrollment. The second group included 611 neonates born to HIV-infected mothers, enrolled during fetal life or before 28 days of age (Group II). In contrast to the older Group I children, all the Group II children were enrolled before their HIV status was ascertained. Interventions According to the study protocol, children underwent a series of cardiac evaluations including two-dimensional echocardiogram and Doppler studies of cardiac function every 4 to 6 months. They also had a 12-or 15-lead surface electrocardiogram (ECG), 24-hour ambulatory ECG monitoring, and a chest radiograph every 12 months. Outcome Measures Main outcome measures were the cumulative incidence of an initial episode of left ventricular (LV) dysfunction, cardiac enlargement, and congestive heart failure (CHF). Because cardiac abnormalities tended to cluster in the same patients, we also determined the number of children who had cardiac impairment which we defined as having either left ventricular fractional shortening (LV FS) ≤25% after 6 months of age, CHF, or treatment with cardiac medications. Results: Cardiac Abnormalities In Group I children (older cohort), the prevalence of decreased LV function (FS ≤25%) was 5.7% and the 2-year cumulative incidence (excluding prevalent cases) was 15.3%. The prevalence of echocardiographic LV enlargement (LV end-diastolic dimension z score >2) at the time of the first echocardiogram was 8.3%. The cumulative incidence of LV enddiastolic enlargement was 11.7% after 2 years. The cumulative incidence of CHF and/or the use of cardiac medications was 10.0% in Group I children. There were 14 prevalent cases of cardiac impairment (LV FS ≤25% after 6 months of age, CHF, or treatment with cardiac medications) in Group I. After excluding these prevalent cases, the 2-year cumulative incidence of cardiac impairment was 19.1% among Group I children and 80.9% remained free of cardiac impairment after 2 years of follow-up. Within Group II (neonatal cohort), the 2-year cumulative incidence of decreased LV FS was 10.7% in the HIV-infected children compared with 3.1% in the HIV-uninfected children. LV dilatation was also more common in Group II infected versus uninfected children (8.7% vs 2.1%). The cumulative incidence of CHF and/or the use of cardiac medications was 8.8% in Group II infected versus 0.5% in uninfected subjects. The 1- and 2-year cumulative incidence rates of cardiac impairment for Group II infected children were 10.1% and 12.8%, respectively, with 87.2% free of cardiac impairment after the first 2 years of life. Mortality In the Group I cohort, the 2-year cumulative death rate from all causes was 16.9% [95% CI: 11.7%–22.1%]. The 1- and 2-year mortality rates after the diagnosis of CHF (Kaplan-Meier estimates) were 69% and 100%, respectively. In the Group II cohort, the 2-year cumulative death rate from all causes was 16.3% [95% CI: 8.8%–23.9%] in the HIV-infected children compared with no deaths among the 463 uninfected Group II children. Two of the 4 Group II children with CHF died during the 2-year observation period and 1 more died within 2 years of the diagnosis of CHF. The 2-year mortality rate after the diagnosis of CHF was 75%. Conclusions This study reports that in addition to subclinical cardiac abnormalities previously reported by the P2C2 Study Group, an important number of HIV-infected children develop clinical heart disease. Over a 2-year period, approximately 10% of HIV-infected children had CHF or were treated with cardiac medications. In addition, approximately 20% of HIV-infected children developed depressed LV function or LV dilatation and it is likely that these abnormalities are hallmarks of future clinically important cardiac dysfunction. Cardiac abnormalities were found in both the older (Group I) as well as the neonatal cohort (Group II) (whose HIV infection status was unknown before enrollment) thereby minimizing potential selection bias based on previously known heart disease. Based on these findings, we recommend that clinicians need to maintain a high degree of suspicion for heart disease in HIV-infected children. All HIV-infected infants and children should have a thorough baseline cardiac evaluation. Patients who develop symptoms of heart or lung disease should undergo more detailed cardiac examinations including ECG and cardiac ultrasound. PMID:10429132

  7. Cardiac Surgeryduring Pregnancy

    PubMed Central

    Patel, Anish; Asopa, Sanjay; Tang, Augustine T.M.; Ohri, Sunil K.

    2008-01-01

    Cardiovascular adaptations during pregnancy are normally well tolerated in healthy women. However, 2% to 4% of women of childbearing age have some degree of concomitant heart disease, and these changes may compromise cardiac function. Of these, a few who do not respond to medical treatment may require surgical correction. In this setting, maternal mortality rate has improved to levels similar to those in non-pregnant counterparts. However, the fetal mortality rate remains high (up to 33%). Factors contributing to high fetal mortality rates include the timing of the operation, the urgency of the operation, and the fetal/fetoplacental response to cardiopulmonary bypass. Modulation of the fetoplacental response to cardiopulmonary bypass may prevent placental dysfunction and sustained uterine contractions, which underlie fetal hypoxia and acidosis. In this article, we review cardiovascular adaptations to pregnancy and the pathophysiologic effects of cardiopulmonary bypass on the mother, fetus, and fetoplacental unit, and we talk about whether manipulation of these responses can help in improving fetal outcome. Finally, approaches regarding perfusion management and off-pump cardiac surgical techniques in pregnancy are discussed. PMID:18941609

  8. Cardiac rehabilitation in Germany.

    PubMed

    Cantwell, J D

    1976-09-01

    The concept of cardiac reconditioning centers for the prevention and rehabilitation of coronary patients has been tremendously successful in Germany over the past 20 years. At least 40 such centers are located throughout the country. Physicians, nurses, and physical therapists work closely together in the various facets of the rehabilitation process. The financial backing for these facilities is primarily through governmental and regional insurance companies, whose officials are apparently convinced that in the long run supporting preventive measures is financially sound. Objective data supporting their convictions come from studies such as that of Brusis, who showed that such as that of 1,500 employees was diminished by nearly 70 percent during a two-year period after cardiac reconditioning, as compared to a similar time period before the rehabilitation experience. Subjective benefits, which are extremely difficult to quantitate in meaningful terms, were nonetheless expressed by nearly all the patients with whom I conversed. Perhaps they have experienced the same feelings that Mark Twain did when he observed that "all frets and worries and chafings sank to sleep in the presence of the benignant serenity of the Alps; the Great Spirit of the Mountains breathed his own peace upon their hurt minds and sore hearts and healed them." PMID:959329

  9. Decoding the Cardiac Message

    PubMed Central

    Dorn, Gerald W

    2012-01-01

    This review reflects and expands upon the contents of the author’s presentation at The Thomas W. Smith Memorial Lecture at AHA Scientific Sessions, 2011. “Decoding the cardiac message” refers to accumulating results from ongoing microRNA research that is altering longstanding concepts of the mechanisms for, and consequences of, messenger RNA (mRNA) regulation in the heart. First, I provide a brief historical perspective of the field of molecular genetics, touching upon seminal research that paved the way for modern molecular cardiovascular research and helped establish the foundation for current concepts of mRNA regulation in the heart. I follow with some interesting details about the specific research that led to the discovery and appreciation of microRNAs as highly conserved pivotal regulators of RNA expression and translation. Finally, I provide a personal viewpoint as to how agnostic genome-wide techniques for measuring microRNAs, their mRNA targets, and their protein products can be applied in an integrated multi-systems approach to uncover direct and indirect effects of microRNAs. Experimental designs integrating next-generation sequencing and global proteomics have the potential to address unanswered questions regarding microRNA-mRNA interactions in cardiac disease, how disease alters mRNA targeting by specific microRNAs, and how mutational and polymorphic nucleotide variation in microRNAs can affect end-organ function and stress-response. PMID:22383710

  10. Cardiac Remodeling in Obesity

    PubMed Central

    ABEL, E. DALE; LITWIN, SHELDON E.; SWEENEY, GARY

    2010-01-01

    The dramatic increase in the prevalence of obesity and its strong association with cardiovascular disease have resulted in unprecedented interest in understanding the effects of obesity on the cardiovascular system. A consistent, but puzzling clinical observation is that obesity confers an increased susceptibility to the development of cardiac disease, while at the same time affording protection against subsequent mortality (termed the obesity paradox). In this review we focus on evidence available from human and animal model studies and summarize the ways in which obesity can influence structure and function of the heart. We also review current hypotheses regarding mechanisms linking obesity and various aspects of cardiac remodeling. There is currently great interest in the role of adipokines, factors secreted from adipose tissue, and their role in the numerous cardiovascular complications of obesity. Here we focus on the role of leptin and the emerging promise of adiponectin as a cardioprotective agent. The challenge of understanding the association between obesity and heart failure is complicated by the multifaceted interplay between various hemodynamic, metabolic, and other physiological factors that ultimately impact the myocardium. Furthermore, the end result of obesity-associated changes in the myocardial structure and function may vary at distinct stages in the progression of remodeling, may depend on the individual pathophysiology of heart failure, and may even remain undetected for decades before clinical manifestation. Here we summarize our current knowledge of this complex yet intriguing topic. PMID:18391168

  11. Anaesthesia for cardiac surgery.

    PubMed

    Rooney, P

    1996-09-01

    Perhaps no form of surgery is as emotive as that on the heart. From ancient times, seen as the seat of the emotions, the heart has been recognised as a vital if, at times, mysterious organ. Its grip on the imagination of primitive peoples is exemplified in the extreme by the climax of the human sacrificial ceremonies carried out by the Aztec and Inca peoples of Mexico and Peru: the holding aloft by the priest of the victim's still-beating heart. Nowadays, although we might congratulate ourselves on the heights of civilization which we have attained, it is salutary to consider that such cultural achievements are but a veneer through which primordial emotions frequently burst. As professional nurses, however, while appreciating the emotions of our patients and relatives with regard to cardiac surgery, we need to exercise sufficient detachment so that effective care may be delivered. This article will discuss cardiac anaesthesia generally, but will not touch on the specialised subjects of transplantation. It also accepts that techniques and drug regimes vary from centre to centre. PMID:8974510

  12. Safer Cardiac Surgery

    PubMed Central

    Merry, Alan F.

    2009-01-01

    Abstract: Safety in cardiac surgery should be evaluated in the context of the other elements of quality in healthcare (timeliness, effectiveness, efficiency, equity, and most importantly, patientcenteredness). Mortality alone is not an adequate index of safety: Stroke is particularly feared by patients and prolonged periods of hospitalization can be very difficult for families to cope with. Advances in knowledge, technology, and medications have improved outcomes, but pharmacological means of reducing cerebral dysfunction after cardiopulmonary bypass remain elusive. Clear differences can be demonstrated between the results of different surgeons and also between different anesthesiologists. The World Health Organization’s recently introduced Surgical Safety Checklist provides a validated and inexpensive cognitive aid to reduce human error and improve teamwork and communication in the operating room. Patient selection is very important, and patients should be given clear information on the relative merits of alternative treatments (for example, coronary surgery, percutaneous intervention, and medical treatment in the case of coronary artery disease). In the end, outcomes that the patients themselves desire are the most meaningful endpoint of the pursuit of safer cardiac surgery. PMID:20092087

  13. Pediatric cardiac surgery in Indonesia.

    PubMed

    Asou, T; Rachmat, J

    1998-10-01

    Pediatric cardiac surgery in Indonesia first developed thanks to the cooperation of various cardiac centers abroad. The establishment of the 'Harapan Kita' National Cardiac Center in 1985 was one of the most important initial steps. Thereafter, the discipline advanced remarkably in terms of the number of the operations performed and the variety of the diseases treated and, as a result, the surgical outcome also improved. Numerous problems remain to be solved. Only 1% of the children with congenital heart disease are today properly treated in Indonesia. Some of the underlying problems responsible for this situation include a shortage of pediatric cardiac professionals, the lack of the information and education on the part of the patients, and a shortage of funding, both privately and publicly. It would thus be welcome for pediatric cardiac surgeons, cardiologists and nurses in Indonesia to learn about congenital heart disease from doctors and nurses in advanced countries in order to improve the outlook at home. PMID:9855095

  14. Challenges in Cardiac Tissue Engineering

    PubMed Central

    Tandon, Nina; Godier, Amandine; Maidhof, Robert; Marsano, Anna; Martens, Timothy P.; Radisic, Milica

    2010-01-01

    Cardiac tissue engineering aims to create functional tissue constructs that can reestablish the structure and function of injured myocardium. Engineered constructs can also serve as high-fidelity models for studies of cardiac development and disease. In a general case, the biological potential of the cell—the actual “tissue engineer”—is mobilized by providing highly controllable three-dimensional environments that can mediate cell differentiation and functional assembly. For cardiac regeneration, some of the key requirements that need to be met are the selection of a human cell source, establishment of cardiac tissue matrix, electromechanical cell coupling, robust and stable contractile function, and functional vascularization. We review here the potential and challenges of cardiac tissue engineering for developing therapies that could prevent or reverse heart failure. PMID:19698068

  15. Noninvasive subject-specific monitoring of autonomic-cardiac regulation.

    PubMed

    Ataee, Pedram; Hahn, Jin-Oh; Dumont, Guy A; Boyce, W Thomas

    2014-04-01

    This paper presents a feasibility study of a model-based approach to noninvasive and subject-specific monitoring of autonomic-cardiac regulation. The proposed approach is built upon individualizing a physiologically-based model by applying a parameter estimation method to routine clinical observations, thereby assuring physical transparency, computational efficiency, and clinical adaptability. To develop an efficient parameter estimation procedure, a parametric sensitivity analysis was performed on the autonomic-cardiac regulation model to identify high-sensitivity model parameters whose changes exert significant impacts on the system outputs. Then, a parameter estimation problem formulated as a nonlinear optimization was solved to estimate high-sensitivity model parameters associated with autonomic-cardiac regulation, whereas the remaining parameters were fixed at their nominal values. The proposed approach can potentially monitor temporal changes in autonomic-cardiac regulation by identifying time-varying changes in the autonomic-cardiac model parameters, including sympathetic and parasympathetic nerve activities on the heart (modulating heart rate), and sympathetic nerve activity on the arterial tree (modulating total peripheral resistance). The proof-of-concept for the proposed approach was tested using a number of experimental data from the MIMIC database and the orthostatic hypotension tests. Our finding shows that the proposed approach is able to provide low-variance estimates of the autonomic-cardiac model parameters, which are consistent with their anticipated behaviors inferred from the physiologic knowledge. An extensive comparison study must be conducted in the future to establish the clinical validity of the proposed approach. PMID:24658244

  16. Myocardial metabolism during hypoxia: Maintained lactate oxidation during increased glycolysis

    SciTech Connect

    Mazer, C.D.; Stanley, W.C.; Hickey, R.F.; Neese, R.A.; Cason, B.A.; Demas, K.A.; Wisneski, J.A.; Gertz, E.W. )

    1990-09-01

    In the intact animal, myocardial lactate utilization and oxidation during hypoxia are not well understood. Nine dogs were chronically instrumented with flow probes on the left anterior descending coronary artery and with a coronary sinus sampling catheter. ({sup 14}C)lactate and ({sup 13}C)glucose tracers, or ({sup 13}C)lactate and ({sup 14}C)glucose were administered to quantitate lactate and glucose oxidation, lactate conversion to glucose, and simultaneous lactate extraction and release. The animals were anesthetized and exposed to 90 minutes of severe hypoxia (PO2 = 25 +/- 4 torr). Hypoxia resulted in significant increases in heart rate, cardiac output and myocardial blood flow, but no significant change in myocardial oxygen consumption. The arterial/coronary sinus differences for glucose and lactate did not change from normoxia to hypoxia; however, the rate of glucose uptake increased significantly due to the increase in myocardial blood flow. Tracer-measured lactate extraction did not decrease with hypoxia, despite a 250% increase in lactate release. During hypoxia, 90% +/- 4% of the extracted {sup 14}C-lactate was accounted for by the appearance of {sup 14}CO{sub 2} in the coronary sinus, compared with 88% +/- 4% during normoxia. Thus, in addition to the expected increase in glucose uptake and lactate production, we observed an increase in lactate oxidation during hypoxia.

  17. [No compression of cardiac cavities in transthoracic ultrasound does not exclude cardiac tamponade.

    PubMed

    Juhl-Olsen, Peter; Frederiksen, Christina Alcaraz; Sloth, Erik

    2014-11-24

    The clinical presentation of cardiac tamponade is difficult to distinguish from other causes of shock. Pericardial fluid is easy to visualize with cardiac ultrasound and a key sign of overt cardiac tamponade is the compression of right side cavities. We present two cases in which cardiac tamponade was present, but where compression of cardiac cavities could not be demon-strated with transthoracic cardiac ultrasound. This emphasizes that cardiac tamponade is still a clinical diagnosis. PMID:25430575

  18. Effect of hypokinesia on cardiac contractile function and nervous regulation of the heart

    NASA Technical Reports Server (NTRS)

    Meyerson, F. Z.; Kapelko, V. I.; Gorina, M. S.; Shchegolkov, A. N.; Larinov, N. P.

    1980-01-01

    Longterm hypokinesia caused cardiac deadaptation in rabbits, which resulted in the diminishing of the left ventricular rate of contraction and relaxation, joined later by decreased vascular resistance. As a results, the ejection rate as well as stroke volume and cardiac output were normal. The decrease of the relaxation speed was more obvious at a high heart rate and results in shortening of the diastolic pause and diminishing of cardiac output. Hearts of the hypokinetic animals were characterized by normal maximal pressure developed by a unit of muccardial mass aorta clamping, decreased adrenoreactivity, and increased cholinoreactivity. This complex of changes is contrary to changes observed in adaptation to exercise, but is similar to changes observed in compensatory hypertrophy of the heart.

  19. Congestive cardiac failure: central role of the arterial blood pressure.

    PubMed Central

    Harris, P

    1987-01-01

    A review of the history of our knowledge and understanding of the peripheral oedema of congestive cardiac failure points to the conclusion that an inability of the heart to maintain the arterial pressure is of central importance in this condition. Although the function of the circulation is to perfuse the tissues, the body monitors the adequacy of its perfusion, not not through metabolic messengers carried from the tissues in the blood stream, but by sensing the arterial pressure; and the mechanisms evoked act to maintain the arterial pressure. In the short term this is achieved by autonomic regulation of the heart and blood vessels; in the longer term the arterial pressure is maintained through an increase in the blood volume by a retention of salt and water by the kidney. To support the latter process, intrinsic renal mechanisms are successively magnified by the renin-angiotensin-aldosterone system and by the activities of the sympathetic system and vasopressin. The natriuretic influence mediated through volume receptors and the release of atrial peptide is overruled by the arterial baroreceptors, so that the body maintains the arterial pressure at the expense of an increase in blood volume. In these ways the syndrome of congestive cardiac failure may be regarded as one which arises when the heart becomes chronically unable to maintain an appropriate arterial pressure without support. PMID:3311096

  20. Cardiac Biomarkers and Acute Kidney Injury After Cardiac Surgery

    PubMed Central

    Bucholz, Emily M.; Whitlock, Richard P.; Zappitelli, Michael; Devarajan, Prasad; Eikelboom, John; Garg, Amit X.; Philbrook, Heather Thiessen; Devereaux, Philip J.; Krawczeski, Catherine D.; Kavsak, Peter; Shortt, Colleen

    2015-01-01

    OBJECTIVES: To examine the relationship of cardiac biomarkers with postoperative acute kidney injury (AKI) among pediatric patients undergoing cardiac surgery. METHODS: Data from TRIBE-AKI, a prospective study of children undergoing cardiac surgery, were used to examine the association of cardiac biomarkers (N-type pro–B-type natriuretic peptide, creatine kinase-MB [CK-MB], heart-type fatty acid binding protein [h-FABP], and troponins I and T) with the development of postoperative AKI. Cardiac biomarkers were collected before and 0 to 6 hours after surgery. AKI was defined as a ≥50% or 0.3 mg/dL increase in serum creatinine, within 7 days of surgery. RESULTS: Of the 106 patients included in this study, 55 (52%) developed AKI after cardiac surgery. Patients who developed AKI had higher median levels of pre- and postoperative cardiac biomarkers compared with patients without AKI (all P < .01). Preoperatively, higher levels of CK-MB and h-FABP were associated with increased odds of developing AKI (CK-MB: adjusted odds ratio 4.58, 95% confidence interval [CI] 1.56–13.41; h-FABP: adjusted odds ratio 2.76, 95% CI 1.27–6.03). When combined with clinical models, both preoperative CK-MB and h-FABP provided good discrimination (area under the curve 0.77, 95% CI 0.68–0.87, and 0.78, 95% CI 0.68–0.87, respectively) and improved reclassification indices. Cardiac biomarkers collected postoperatively did not significantly improve the prediction of AKI beyond clinical models. CONCLUSIONS: Preoperative CK-MB and h-FABP are associated with increased risk of postoperative AKI and provide good discrimination of patients who develop AKI. These biomarkers may be useful for risk stratifying patients undergoing cardiac surgery. PMID:25755241

  1. High Output Piezo/Triboelectric Hybrid Generator

    NASA Astrophysics Data System (ADS)

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-03-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA.cm-2, and average power density of ~4.44 mW.cm-2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics.

  2. High output piezo/triboelectric hybrid generator.

    PubMed

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-01-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA · cm(-2), and average power density of ~4.44 mW · cm(-2). The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics. PMID:25791299

  3. High Output Piezo/Triboelectric Hybrid Generator

    PubMed Central

    Jung, Woo-Suk; Kang, Min-Gyu; Moon, Hi Gyu; Baek, Seung-Hyub; Yoon, Seok-Jin; Wang, Zhong-Lin; Kim, Sang-Woo; Kang, Chong-Yun

    2015-01-01

    Recently, piezoelectric and triboelectric energy harvesting devices have been developed to convert mechanical energy into electrical energy. Especially, it is well known that triboelectric nanogenerators have a simple structure and a high output voltage. However, whereas nanostructures improve the output of triboelectric generators, its fabrication process is still complicated and unfavorable in term of the large scale and long-time durability of the device. Here, we demonstrate a hybrid generator which does not use nanostructure but generates much higher output power by a small mechanical force and integrates piezoelectric generator into triboelectric generator, derived from the simultaneous use of piezoelectric and triboelectric mechanisms in one press-and-release cycle. This hybrid generator combines high piezoelectric output current and triboelectric output voltage, which produces peak output voltage of ~370 V, current density of ~12 μA·cm−2, and average power density of ~4.44 mW·cm−2. The output power successfully lit up 600 LED bulbs by the application of a 0.2 N mechanical force and it charged a 10 μF capacitor to 10 V in 25 s. Beyond energy harvesting, this work will provide new opportunities for developing a small, built-in power source in self-powered electronics such as mobile electronics. PMID:25791299

  4. Cardiac performance in the zebrafish breakdance mutant.

    PubMed

    Kopp, Renate; Schwerte, Thorsten; Pelster, Bernd

    2005-06-01

    In the Tubingen screen a breakdance mutant of zebrafish (bre) was described as an arrhythmia, in which the ventricle beats only with every second atrial contraction (2:1 rhythm). Surprisingly, a careful analysis of the effect of the breakdance mutation on cardiac performance of the zebrafish during development between 3 d.p.f. and 14 d.p.f revealed that homozygous bre mutants did not always show the 2:1 rhythm. Cardiac activity was continuously recorded for a period of 20 min in each larva, and during this period we observed that heart rate randomly switched between the 2:1 rhythm and a 1:1 rhythm. Furthermore, at 28 degrees C and at 31 degrees C the expression of the 2:1 rhythm decreased with development. At 31 degrees C this was in part due to a significantly reduced survival rate of mutants beyond 4 d.p.f. Besides development, temperature had a marked effect on the expression of the 2:1 rhythm, and during the first days of development the expression of the 2:1 rhythm was significantly higher at elevated incubation temperatures. By contrast, in the 2:1 beating heart ventricular contraction rate was about 80 beats min(-1) throughout development irrespective of the temperature, and even in the 1:1 rhythm mutants showed a significant bradycardia at all three temperatures (25 degrees C, 28 degrees C or 31 degrees C). Compared to wild-type animals, cardiac output was significantly lower in bre mutants. Pressure traces recorded in the ventricle of mutants revealed a prolonged relaxation phase, indicating that the second pacemaker current could not be conveyed to the ventricle (AV-block). This phenotype is comparable to the human Long QT Syndrome, an arrhythmia caused by a modification of an ion channel involved in cardiac repolarization. The bradycardia and the modified temperature sensitivity of heart rate suggested that the activity of the pacemaker cells was also affected by this mutation. PMID:15914656

  5. [A case of primary cardiac angiosarcoma associated with cardiac tamponade].

    PubMed

    Nakaya, Naoki; Sato, Itaru; Shimasaki, Takeo; Nakajima, Hideo; Kurose, Nozomu; Nojima, Takayuki; Motoo, Yoshiharu

    2011-08-01

    A 72-year-old man came to our hospital due to edema, malaise, and poor appetite in May 200X. He was diagnosed as cardiac tamponade, and open surgery revealed tumors in the right atrium and the left ventricule. Tumor tissue was revealed to be angiosarcoma by the pathological findings. Metastases to the brain, lungs, liver, and adrenal glands were found. The patient was treated with interleukin-2(IL-2)for 7 weeks. However, there was no anti-tumor effect, and the patient died in September, 200X. We reported a very rare case of cardiac angiosarcoma associated with cardiac tamponade, who was treated with IL-2 monotherapy. PMID:21829080

  6. A Modular Approach to Cardiac Tissue Engineering

    PubMed Central

    Leung, Brendan M.

    2010-01-01

    Functional cardiac tissue was prepared using a modular tissue engineering approach with the goal of creating vascularized tissue. Rat aortic endothelial cells (RAEC) were seeded onto submillimeter-sized modules made of type I bovine collagen supplemented with Matrigel™ (25% v/v) embedded with cardiomyocyte (CM)-enriched neonatal rat heart cells and assembled into a contractile, macroporous, sheet-like construct. Modules (without RAEC) cultured in 10% bovine serum (BS) were more contractile and responsive to external stimulus (lower excitation threshold, higher maximum capture rate, and greater en face fractional area changes) than modules cultured in 10% fetal BS. Incorporating 25% Matrigel in the matrix reduced the excitation threshold and increased the fractional area change relative to collagen only modules (without RAEC). A coculture medium, containing 10% BS, low Mg2+ (0.814 mM), and normal glucose (5.5 mM), was used to maintain RAEC junction morphology (VE-cadherin) and CM contractility, although the responsiveness of CM was attenuated with RAEC on the modules. Macroporous, sheet-like module constructs were assembled by partially immobilizing a layer of modules in alginate gel until day 8, with or without RAEC. RAEC/CM module sheets were electrically responsive; however, like modules with RAEC this responsiveness was attenuated relative to CM-only sheets. Muscle bundles coexpressing cardiac troponin I and connexin-43 were evident near the perimeter of modules and at intermodule junctions. These results suggest the potential of the modular approach as a platform for building vascularized cardiac tissue. PMID:20504074

  7. Design of hydraulic output Stirling engine

    NASA Technical Reports Server (NTRS)

    Toscano, W. M.; Harvey, A. C.; Lee, K.

    1983-01-01

    A hydraulic output system for the RE-1000 free piston stirling engine (FPSE) was designed. The hydraulic output system can be readily integrated with the existing hot section of RE-1000 FPSE. The system has two simply supported diaphragms which separate the engine gas from the hydraulic fluid, a dynamic balance mechanism, and a novel, null center band hydraulic pump. The diaphragms are designed to endure more than 10 billion cycles, and to withstand the differential pressure load as high as 14 MPa. The projected thermodynamic performance of the hydraulic output version of RE-1000 FPSE is 1.87 kW at 29/7 percent brake efficiency.

  8. High Energy Output Marx Generator Design

    SciTech Connect

    Monty Lehmann

    2011-07-01

    High Energy Output Marx Generator Design a design of a six stage Marx generator that has a unipolar pulse waveform of 200 kA in a 50×500 microsecond waveform is presented. The difficulties encountered in designing the components to withstand the temperatures and pressures generated during the output pulse are discussed. The unique methods and materials used to successfully overcome these problems are given. The steps necessary to increase the current output of this Marx generator design to the meg-ampere region or higher are specified.

  9. Cardiac resynchronization therapy or sequential pacing in failing Mustard?

    PubMed

    Morani, Giovanni; Luciani, Giovanni Battista; Manica, Anna; Prioli, Maria Antonia; Franceschini, Lorenzo; Tomei, Ruggero; Vassanelli, Corrado

    2011-01-01

    The atrial switch (Mustard, Senning procedures) was one of the treatments of choice for repair of transposition of the great arteries from the early 1960s to the mid-1980s. A significant proportion of patients with atrial switch develops systemic (right) ventricular failure. A series of surgical therapeutic options exists to manage cardiac failure in this setting, and, more recently proposed, cardiac resynchronization therapy. We describe case report of a 30-year-old woman with congenital heart disease (CHD) and previous Mustard procedure who underwent upgrading from single chamber to dual-chamber pacemaker. The narrower native QRS did not correlate with a better synchrony status nor with a better cardiac output. Functional evaluation confirmed a better performance in DDD mode with short atrioventricular delay and broad QRS. Some echocardiographic and electrocardiographic parameters, such as ejection fraction and QRS duration, well established in adults' heart for selection of candidates to cardiac resynchronization therapy, are much less studied in CHD. Postoperative CHD may provide unique patterns of asynchrony with poorly predictable hemodynamic outcome. PMID:20832821

  10. Modelling of an oesophageal electrode for cardiac function tomography.

    PubMed

    Tehrani, J Nasehi; Jin, C; McEwan, A L

    2012-01-01

    There is a need in critical care units for continuous cardiopulmonary monitoring techniques. ECG gated electrical impedance tomography is able to localize the impedance variations occurring during the cardiac cycle. This method is a safe, inexpensive and potentially fast technique for cardiac output imaging but the spatial resolution is presently low, particularly for central locations such as the heart. Many parameters including noise deteriorate the reconstruction result. One of the main obstacles in cardiac imaging at the heart location is the high impedance of lungs and muscles on the dorsal and posterior side of body. In this study we are investigating improvements of the measurement and initial conductivity estimation of the internal electrode by modelling an internal electrode inside the esophagus. We consider 16 electrodes connected around a cylindrical mesh. With the random noise level set near 0.05% of the signal we evaluated the Graz consensus reconstruction algorithm for electrical impedance tomography. The modelling and simulation results showed that the quality of the target in reconstructed images was improved by up to 5 times for amplitude response, position error, resolution, shape deformation and ringing effects with perturbations located in cardiac related positions when using an internal electrode. PMID:22481975

  11. Right atrial tamponade complicating cardiac operation: clinical, hemodynamic, and scintigraphic correlates

    SciTech Connect

    Bateman, T.; Gray, R.; Chaux, A.; Lee, M.; De Robertis, M.; Berman, D.; Matloff, J.

    1982-09-01

    Persistent bleeding into the pericardial space in the early hours after cardiac operation not uncommonly results in cardiac tamponade. Single chamber tamponade also might be expected, since in this setting the pericardium frequently contains firm blood clots localized to the area of active bleeding. However, this complication has received very little attention in the surgical literature. We are therefore providing documentation that isolated right atrial tamponade can occur as a complication of cardiac operation and that there exists a potential for misdiagnosis and hence incorrect treatment of this condition. Right atrial tamponade may be recognized by a combination of low cardiac output, low blood pressure, prominent neck veins, right atrial pressure in excess of pulmonary capillary wedge pressure and right ventricular end-diastolic pressure, and a poor response to plasma volume expansion. Findings on chest roentgenogram and gated wall motion scintigraphy may be highly suggestive. This review should serve to increase awareness of this complication and to provide some helpful diagnostic clues.

  12. Programmed Evolution for Optimization of Orthogonal Metabolic Output in Bacteria

    PubMed Central

    Eckdahl, Todd T.; Campbell, A. Malcolm; Heyer, Laurie J.; Poet, Jeffrey L.; Blauch, David N.; Snyder, Nicole L.; Atchley, Dustin T.; Baker, Erich J.; Brown, Micah; Brunner, Elizabeth C.; Callen, Sean A.; Campbell, Jesse S.; Carr, Caleb J.; Carr, David R.; Chadinha, Spencer A.; Chester, Grace I.; Chester, Josh; Clarkson, Ben R.; Cochran, Kelly E.; Doherty, Shannon E.; Doyle, Catherine; Dwyer, Sarah; Edlin, Linnea M.; Evans, Rebecca A.; Fluharty, Taylor; Frederick, Janna; Galeota-Sprung, Jonah; Gammon, Betsy L.; Grieshaber, Brandon; Gronniger, Jessica; Gutteridge, Katelyn; Henningsen, Joel; Isom, Bradley; Itell, Hannah L.; Keffeler, Erica C.; Lantz, Andrew J.; Lim, Jonathan N.; McGuire, Erin P.; Moore, Alexander K.; Morton, Jerrad; Nakano, Meredith; Pearson, Sara A.; Perkins, Virginia; Parrish, Phoebe; Pierson, Claire E.; Polpityaarachchige, Sachith; Quaney, Michael J.; Slattery, Abagael; Smith, Kathryn E.; Spell, Jackson; Spencer, Morgan; Taye, Telavive; Trueblood, Kamay; Vrana, Caroline J.; Whitesides, E. Tucker

    2015-01-01

    Current use of microbes for metabolic engineering suffers from loss of metabolic output due to natural selection. Rather than combat the evolution of bacterial populations, we chose to embrace what makes biological engineering unique among engineering fields – evolving materials. We harnessed bacteria to compute solutions to the biological problem of metabolic pathway optimization. Our approach is called Programmed Evolution to capture two concepts. First, a population of cells is programmed with DNA code to enable it to compute solutions to a chosen optimization problem. As analog computers, bacteria process known and unknown inputs and direct the output of their biochemical hardware. Second, the system employs the evolution of bacteria toward an optimal metabolic solution by imposing fitness defined by metabolic output. The current study is a proof-of-concept for Programmed Evolution applied to the optimization of a metabolic pathway for the conversion of caffeine to theophylline in E. coli. Introduced genotype variations included strength of the promoter and ribosome binding site, plasmid copy number, and chaperone proteins. We constructed 24 strains using all combinations of the genetic variables. We used a theophylline riboswitch and a tetracycline resistance gene to link theophylline production to fitness. After subjecting the mixed population to selection, we measured a change in the distribution of genotypes in the population and an increased conversion of caffeine to theophylline among the most fit strains, demonstrating Programmed Evolution. Programmed Evolution inverts the standard paradigm in metabolic engineering by harnessing evolution instead of fighting it. Our modular system enables researchers to program bacteria and use evolution to determine the combination of genetic control elements that optimizes catabolic or anabolic output and to maintain it in a population of cells. Programmed Evolution could be used for applications in energy, pharmaceuticals, chemical commodities, biomining, and bioremediation. PMID:25714374

  13. Cardiac rehabilitation in India.

    PubMed

    Madan, Kushal; Babu, Abraham Samuel; Contractor, Ashish; Sawhney, Jitendra Pal Singh; Prabhakaran, Dorairaj; Gupta, Rajeev

    2014-01-01

    Cardiovascular diseases (CVDs) are the leading cause of death and disability in India. Moreover, mortality following an acute myocardial infarction is high, which may be due to gaps in secondary prevention in general and a lack of cardiac rehabilitation (CR) services in particular. This review discusses the availability of CR in India, its putative role in reducing adverse outcomes over the long-term and suggests a road map for future research to enhance CR in this country. Currently, there is limited evidence, conducted in India, demonstrating CR efficacy. Moreover, there is currently limited availability of outpatient CR programs in India. Even so, there is consensus that CR is effective and essential in the CVD population. Therefore, efforts are needed to continue CR research in India and facilitate clinical implementation. PMID:24607020

  14. Physics of Cardiac Arrhythmogenesis

    NASA Astrophysics Data System (ADS)

    Karma, Alain

    2013-04-01

    A normal heartbeat is orchestrated by the stable propagation of an excitation wave that produces an orderly contraction. In contrast, wave turbulence in the ventricles, clinically known as ventricular fibrillation (VF), stops the heart from pumping and is lethal without prompt defibrillation. I review experimental, computational, and theoretical studies that have shed light on complex dynamical phenomena linked to the initiation, maintenance, and control of wave turbulence. I first discuss advances made to understand the precursor state to a reentrant arrhythmia where the refractory period of cardiac tissue becomes spatiotemporally disordered; this is known as an arrhythmogenic tissue substrate. I describe observed patterns of transmembrane voltage and intracellular calcium signaling that can contribute to this substrate, and symmetry breaking instabilities to explain their formation. I then survey mechanisms of wave turbulence and discuss novel methods that exploit electrical pacing stimuli to control precursor patterns and low-energy pulsed electric fields to control turbulence.

  15. Cardiac ventricular aneurysm

    PubMed Central

    Harley, Hugh R. S.

    1969-01-01

    A case of successful excision of a ventricular aneurysm due to myocardial infarction is presented. The aetiology, incidence, pathogenesis, pathology, clinical features, and diagnosis of the condition are discussed. An account is given of the haemodynamic upset caused by aneurysms of the ventricle. The prognosis of untreated aneurysms is discussed. Although there is difference of opinion, it is concluded that a ventricular aneurysm adversely affects the prognosis after myocardial infarction. The indications for, and the mortality and results of, resection of ventricular aneurysms are discussed. The conclusion is drawn that persistent cardiac failure and angina can be relieved and the risk of systemic embolism reduced by the excision of expansile ventricular aneurysms of a fibrous nature. It is possible that excision may also reduce the incidence of subsequent acute myocardial infarction. Images PMID:5821618

  16. Trends in Cardiac Pacemaker Batteries

    PubMed Central

    Mallela, Venkateswara Sarma; Ilankumaran, V; Rao, N.Srinivasa

    2004-01-01

    Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future. PMID:16943934

  17. [Cardiac involvement in systemic sclerosis].

    PubMed

    Silveira-Torre, Luis H

    2006-11-01

    Systemic sclerosis (SS) can involve the pericardium, myocardium, conduction system, and cardiac valves. The presence of overt clinical signs of cardiac disease is a poor prognostic sign. Clinical manifestations include dyspnea, palpitations, chest pain, syncope, and symptoms of right heart failure. Prevalence of clinically symptomatic pericardial disease is 5-16%. However, ecocardiographic prevalence is 5.4- 41% and at autopsy is 33-77.5%. Patchy fibrosis is the characteristic myocardial finding in SS. Contraction band necrosis is the typical pathological finding. Important complications of fibrosis include left ventricular hypertrophy, as well as systolic and diastolic dysfunction of both ventricles. Early detection of these abnormalities is very important, mainly of the diastolic dysfunction, since it occurs before the systolic dysfunction and can predict important cardiac damage. Association of skeletal myositis with myocardial disease has been described. Patients with skeletal myositis are more likely to develop congestive heart failure, sustained symptomatic arrythmias, and cardiac sudden death. Coronary arteries are normal in systemic sclerosis, but there is no endomyocardial vessel involvement. There is an increased prevalence of arrhytmias, mainly premature atrial and ventricular contractions, as well as conduction system disease. Cardiac valvular involvement is minor in systemic sclerosis; mitral valve is the most frequently affected. Other abnormalities described in this disease include peripheral large vessels stiffness and secondary cardiac involvement due to pulmonary and systemic arterial hypertension. Cardiac involvement confers a high morbi-mortality risk in systemic sclerosis. PMID:21794385

  18. Improving the stability of cardiac mechanical simulations.

    PubMed

    Land, Sander; Niederer, Steven A; Lamata, Pablo; Smith, Nicolas P

    2015-03-01

    In the field of cardiac modeling, the mechanical action of the heart is often simulated using finite element methods. These simulations are becoming increasingly challenging as the computational domain is customized to a patient's anatomy, within which large heterogeneous tension gradients are generated via biophysical cell models which drive simulations of the cardiac pump cycle. The convergence of nonlinear solvers in simulations of large deformation mechanics depends on many factors. When extreme stress or irregular deformations are modeled, commonly used numerical methods can often fail to find a solution, which can prevent investigation of interesting parameter variations or use of models in a clinical context with high standards for robustness. This paper outlines a novel numerical method that is straightforward to implement and which significantly improves the stability of these simulations. The method involves adding a compressibility penalty to the standard incompressible formulation of large deformation mechanics. We compare the method's performance when used with both a direct discretization of the equations for incompressible solid mechanics, as well as the formulation based on an isochoric/deviatoric split of the deformation gradient. The addition of this penalty decreases the tendency for solutions to deviate from the incompressibility constraint, and significantly improves the ability of the Newton solver to find a solution. Additionally, our method maintains the expected order of convergence under mesh refinement, has nearly identical solutions for the pressure-volume relations, and stabilizes the solver to allow challenging simulations of both diastolic and systolic function on personalized patient geometries. PMID:25474804

  19. Mechanical communication in cardiac cell synchronized beating

    NASA Astrophysics Data System (ADS)

    Nitsan, Ido; Drori, Stavit; Lewis, Yair E.; Cohen, Shlomi; Tzlil, Shelly

    2016-05-01

    Cell-cell communication, which enables cells to coordinate their activity and is essential for growth, development and function, is usually ascribed a chemical or electrical origin. However, cells can exert forces and respond to environment elasticity and to mechanical deformations created by their neighbours. The extent to which this mechanosensing ability facilitates intercellular communication remains unclear. Here we demonstrate mechanical communication between cells directly for the first time, providing evidence for a long-range interaction that induces long-lasting alterations in interacting cells. We show that an isolated cardiac cell can be trained to beat at a given frequency by mechanically stimulating the underlying substrate. Deformations are induced using an oscillatory mechanical probe that mimics the deformations generated by a beating neighbouring cardiac cell. Unlike electrical field stimulation, the probe-induced beating rate is maintained by the cell for an hour after the stimulation stops, implying that long-term modifications occur within the cell. These long-term alterations provide a mechanism for cells that communicate mechanically to be less variable in their electromechanical delay. Mechanical coupling between cells therefore ensures that the final outcome of action potential pacing is synchronized beating. We further show that the contractile machinery is essential for mechanical communication.

  20. Cardiac action potential imaging

    NASA Astrophysics Data System (ADS)

    Tian, Qinghai; Lipp, Peter; Kaestner, Lars

    2013-06-01

    Action potentials in cardiac myocytes have durations in the order of magnitude of 100 milliseconds. In biomedical investigations the documentation of the occurrence of action potentials is often not sufficient, but a recording of the shape of an action potential allows a functional estimation of several molecular players. Therefore a temporal resolution of around 500 images per second is compulsory. In the past such measurements have been performed with photometric approaches limiting the measurement to one cell at a time. In contrast, imaging allows reading out several cells at a time with additional spatial information. Recent developments in camera technologies allow the acquisition with the required speed and sensitivity. We performed action potential imaging on isolated adult cardiomyocytes of guinea pigs utilizing the fluorescent membrane potential sensor di-8-ANEPPS and latest electron-multiplication CCD as well as scientific CMOS cameras of several manufacturers. Furthermore, we characterized the signal to noise ratio of action potential signals of varying sets of cameras, dye concentrations and objective lenses. We ensured that di-8-ANEPPS itself did not alter action potentials by avoiding concentrations above 5 μM. Based on these results we can conclude that imaging is a reliable method to read out action potentials. Compared to conventional current-clamp experiments, this optical approach allows a much higher throughput and due to its contact free concept leaving the cell to a much higher degree undisturbed. Action potential imaging based on isolated adult cardiomyocytes can be utilized in pharmacological cardiac safety screens bearing numerous advantages over approaches based on heterologous expression of hERG channels in cell lines.

  1. Cardiac cone-beam CT

    SciTech Connect

    Manzke, Robert . E-mail: robert.manzke@philips.com

    2005-10-15

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

  2. Acute thyroid hormone administration increases systemic oxygen delivery and consumption immediately following resuscitation from cardiac arrest without changes in thyroid-stimulating hormone.

    PubMed

    Zwemer, C F; Whitesall, S E; Nachreiner, R F; Mayor, G H; D'Alecy, L G

    1997-01-01

    This study determined the acute effects of intravenous levothyroxine sodium (LT4) on systemic oxygen delivery and consumption for 6 h following resuscitation from 9 min of normothermic cardiac arrest in dogs. Male mongrel dogs (15-25 kg) were randomly assigned to two groups of seven. The treated group received a pre-cardiac arrest infusion of 15 micrograms/kg per h of LT4 for 1.5 h prior to arrest and for 6 h after, while controls received a comparable volume of 0.9 N saline infusion. Neurologic outcome was recorded at 1, 2 and 6 h following resuscitation. Systemic oxygen consumption (VO2), carbon dioxide production (VCO2) and respiratory quotient (RQ) were calculated from directly measured cardiac output, arterial and mixed venous blood gases and contents. Serum levels of circulating canine thyroid-stimulating hormone (cTSH), total thyroxine (T4), free thyroxine (FT4), total 3,5,3'-triiodothyronine (T3), free 3,5,3'-triiodothyronine (FT3), reverse 3,3',5'-triiodothyronine (rT3), and plasma markers of oxidant injury (malonaldehyde (MDA), 4-hydroxynonenal (4-OH) and erythrocyte GSH) were measured before administration and after resuscitation. Following resuscitation, treated dogs maintained significantly higher cardiac output when compared with their control counterparts at 4 h (5.5 ml/g per h vs. 2.9 ml/g per h, respectively, P < 0.05) and at 6 h (5.5 ml/g per h vs. 3.0 mg/g per h, respectively, P < 0.05). The level of VO2 was significantly higher in treated dogs than control dogs at 1, 4 and 6 h (P < 0.05). Treated dogs had significantly elevated levels of T4, FT4, T3, FT3 and rT3 (P < 0.01), compared with control dogs. No changes in cTSH were detected between groups or over time. Acute administration of LT4 enhances systemic oxygen delivery and apparently, therefore, oxygen consumption following resuscitation. PMID:9044499

  3. 7 CFR 784.12 - Maintaining records.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... Persons making application for benefits under this program must maintain accurate records and accounts... program. Destruction of the records after such date shall be at the risk of the party undertaking...

  4. Ecology: Tribal Warfare Maintains Microbial Diversity.

    PubMed

    Greig, Duncan; Goddard, Matthew

    2015-07-20

    When two tribes of Myxococcus bacteria attack each other, the most numerous usually wins. Established colonies can therefore resist invaders by outnumbering them. This shows how positive frequency dependence can maintain diversity across spatially structured environments. PMID:26196492

  5. Mechanisms maintaining grassland biodiversity and ecosystem stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecologists need to know how particular processes influence biodiversity and ecosystem stability. We demonstrate how data from biodiversity-ecosystem functioning experiments can be used to identify and quantify the classes of mechanisms maintaining biodiversity and ecosystem stability. We predicted...

  6. Scaling of global input-output networks

    NASA Astrophysics Data System (ADS)

    Liang, Sai; Qi, Zhengling; Qu, Shen; Zhu, Ji; Chiu, Anthony S. F.; Jia, Xiaoping; Xu, Ming

    2016-06-01

    Examining scaling patterns of networks can help understand how structural features relate to the behavior of the networks. Input-output networks consist of industries as nodes and inter-industrial exchanges of products as links. Previous studies consider limited measures for node strengths and link weights, and also ignore the impact of dataset choice. We consider a comprehensive set of indicators in this study that are important in economic analysis, and also examine the impact of dataset choice, by studying input-output networks in individual countries and the entire world. Results show that Burr, Log-Logistic, Log-normal, and Weibull distributions can better describe scaling patterns of global input-output networks. We also find that dataset choice has limited impacts on the observed scaling patterns. Our findings can help examine the quality of economic statistics, estimate missing data in economic statistics, and identify key nodes and links in input-output networks to support economic policymaking.

  7. Modeling Plants With Moving-Average Outputs

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    1989-01-01

    Three discrete-state-variable representations derived. Paper discusses mathematical modeling of digital control systems for plants in which outputs include combinations of instantaneous and moving-average-prefiltered measurements.

  8. Output control using feedforward and cascade controllers

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1987-01-01

    An open-loop solution to the output control problem in SISO (single-input, single-output) systems by means of feedforward and cascade controllers is investigated. A simple characterization of feedforward controllers, which achieve steady-state disturbance rejection, is given in a transfer-function setting. Cascade controllers which cause steady-state command tracking are characterized. Disturbance decoupling and command matching controllers are identified. Conditions for existence of feedforward and cascade controllers are given. For unstable systems, it is shown that a stabilizing feedback controller can be used without affecting the feedforward and cascade controllers used for output control; hence, the three controllers can be designed independently. Output control by a combination of feedforward and feedback is discussed.

  9. Memory-based parallel data output controller

    NASA Technical Reports Server (NTRS)

    Stattel, R. J.; Niswander, J. K. (Inventor)

    1984-01-01

    A memory-based parallel data output controller employs associative memories and memory mapping to decommutate multiple channels of telemetry data. The output controller contains a random access memory (RAM) which has at least as many address locations as there are channels. A word counter addresses the RAM which provides as it outputs an encoded peripheral device number and a MSB/LSB-first flag. The encoded device number and a bit counter address a second RAM which contains START and STOP flags to pick out the required bits from the specified word number. The LSB/MSB, START and STOP flags, along with the serial input digital data go to a control block which selectively fills a shift register used to drive the parallel data output bus.

  10. Coupling output of multichannel high power microwaves

    SciTech Connect

    Li Guolin; Shu Ting; Yuan Chengwei; Zhang Jun; Yang Jianhua; Jin Zhenxing; Yin Yi; Wu Dapeng; Zhu Jun; Ren Heming; Yang Jie

    2010-12-15

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  11. Maintainability planning for the Space Station

    NASA Technical Reports Server (NTRS)

    Egan, G. R.

    1986-01-01

    The planned NASA Space Station, which is expected to have many years of on-orbit operation, for the first time confronts spacecraft designers with major questions of maintainability in design. A Maintainability Guidelines Document has been distributed to all Space Station Definition and Preliminary Design personnel of the Space Station Program Office. Trade studies are being performed to determine the most economical balance between initial (reliability) cost and life cycle cost (crew time and replacement hardware) costs.

  12. Proteotoxicity and Cardiac Dysfunction

    PubMed Central

    McLendon, Patrick M.; Robbins, Jeffrey

    2015-01-01

    Baseline physiological function of the mammalian heart is under the constant threat of environmental or intrinsic pathological insults. Cardiomyocyte proteins are thus subject to unremitting pressure to function optimally and this depends upon them assuming and maintaining proper conformation. This review explores the multiple defenses a cell may employ for its proteins to assume and maintain correct protein folding and conformation. There are multiple quality control mechanisms to ensure that nascent polypeptides are properly folded and mature proteins maintain their functional conformation. When proteins do misfold, either in the face of normal or pathologic stimuli or because of intrinsic mutations or post-translational modifications, they must either be refolded correctly or recycled. In the absence of these corrective processes, they may become toxic to the cell. Herein, we explore some of the underlying mechanisms that lead to proteotoxicity. The continued presence and chronic accumulation of misfolded or unfolded proteins can be disastrous in cardiomyocytes as these misfolded proteins can lead to aggregation or the formation of soluble peptides that are proteotoxic. This in turn leads to compromised protein quality control and precipitating a downward spiral of the cell's ability to maintain protein homeostasis. Some underlying mechanisms are discussed and the therapeutic potential of interfering with proteotoxicity in the heart is explored. PMID:25999425

  13. Epigenetic regulation in cardiac fibrosis.

    PubMed

    Yu, Li-Ming; Xu, Yong

    2015-11-26

    Cardiac fibrosis represents an adoptive response in the heart exposed to various stress cues. While resolution of the fibrogenic response heralds normalization of heart function, persistent fibrogenesis is usually associated with progressive loss of heart function and eventually heart failure. Cardiac fibrosis is regulated by a myriad of factors that converge on the transcription of genes encoding extracellular matrix proteins, a process the epigenetic machinery plays a pivotal role. In this mini-review, we summarize recent advances regarding the epigenetic regulation of cardiac fibrosis focusing on the role of histone and DNA modifications and non-coding RNAs. PMID:26635926

  14. Mechanisms of sudden cardiac death

    PubMed Central

    Rubart, Michael; Zipes, Douglas P.

    2005-01-01

    Despite recent advances in preventing sudden cardiac death (SCD) due to cardiac arrhythmia, its incidence in the population at large has remained unacceptably high. Better understanding of the interaction among various functional, structural, and genetic factors underlying the susceptibility to, and initiation of, fatal arrhythmias is a major goal and will provide new tools for the prediction, prevention, and therapy of SCD. Here, we review the role of aberrant intracellular Ca2+ handling, ionic imbalances associated with acute myocardial ischemia, neurohumoral changes, and genetic predisposition in the pathogenesis of SCD due to cardiac arrhythmia. Therapeutic measures to prevent SCD are also discussed. PMID:16138184

  15. Dual gated nuclear cardiac images

    SciTech Connect

    Zubal, I.G.; Bennett, G.W.; Bizais, Y.; Brill, A.B.

    1984-02-01

    A data acquisition system has been developed to collect camera events simultaneously with continually digitized electrocardiograph signals and respiratory flow measurements. Software processing of the list mode data creates more precisely gated cardiac frames. Additionally, motion blur due to heart movement during breathing is reduced by selecting events within a specific respiratory phase. Thallium myocardium images of a healthy volunteer show increased definition. This technique of combined cardiac and respiratory gating has the potential of improving the detectability of small lesions, and the characterization of cardiac wall motion.

  16. Iterative reconstruction in cardiac CT.

    PubMed

    Naoum, Christopher; Blanke, Philipp; Leipsic, Jonathon

    2015-01-01

    Iterative reconstruction (IR) has the ability to reduce image noise in CT without compromising diagnostic quality, which permits a significant reduction in effective radiation dose. This been increasingly integrated into clinical CT practice over the past 7years and has been particularly important in the field of cardiac CT with multiple vendors introducing cardiac CT-compatible IR algorithms. The following review will summarize the principles of IR algorithms, studies validating their noise- and dose-reducing abilities, and the specific applications of IR in cardiac CT. PMID:26088375

  17. Epigenetic regulation in cardiac fibrosis

    PubMed Central

    Yu, Li-Ming; Xu, Yong

    2015-01-01

    Cardiac fibrosis represents an adoptive response in the heart exposed to various stress cues. While resolution of the fibrogenic response heralds normalization of heart function, persistent fibrogenesis is usually associated with progressive loss of heart function and eventually heart failure. Cardiac fibrosis is regulated by a myriad of factors that converge on the transcription of genes encoding extracellular matrix proteins, a process the epigenetic machinery plays a pivotal role. In this mini-review, we summarize recent advances regarding the epigenetic regulation of cardiac fibrosis focusing on the role of histone and DNA modifications and non-coding RNAs. PMID:26635926

  18. Cardiac Involvement in Ankylosing Spondylitis

    PubMed Central

    Ozkan, Yasemin

    2016-01-01

    Ankylosing spondylitis is one of the subgroup of diseases called “seronegative spondyloarthropathy”. Frequently, it affects the vertebral colon and sacroiliac joint primarily and affects the peripheral joints less often. This chronic, inflammatory and rheumatic disease can also affect the extraarticular regions of the body. The extraarticular affections can be ophthalmologic, cardiac, pulmonary or neurologic. The cardiac affection can be 2-10% in all patients. Cardiac complications such as left ventricular dysfunction, aortitis, aortic regurgitation, pericarditis and cardiomegaly are reviewed. PMID:27222669

  19. Videoscope-assisted cardiac surgery

    PubMed Central

    Chen, Robert Jeen-Chen

    2014-01-01

    Videoscope-assisted cardiac surgery (VACS) offers a minimally invasive platform for most cardiac operations such as coronary and valve procedures. It includes robotic and thoracoscopic approaches and each has strengths and weaknesses. The success depends on appropriate hardware setup, staff training, and troubleshooting efficiency. In our institution, we often use VACS for robotic left-internal-mammary-artery takedown, mitral valve repair, and various intra-cardiac operations such as tricuspid valve repair, combined Maze procedure, atrial septal defect repair, ventricular septal defect repair, etc. Hands-on reminders and updated references are provided for reader’s further understanding of the topic. PMID:24455172

  20. Anomalous light output from lightning dart leaders

    NASA Technical Reports Server (NTRS)

    Guo, C.; Krider, E. P.

    1985-01-01

    About 5 percent of the multiple-stroke cloud-to-ground lightning discharges recorded at the NASA Kennedy Space Center during the summer of 1981 contained dart leaders that produced an unusually large light output. An analysis of these cases indicates that the average peak light output per unit length in the leader may be comparable to or even exceed that of the return stroke that follows.

  1. Surface emitting lasers with combined output

    NASA Technical Reports Server (NTRS)

    Carlin, Donald B. (Inventor)

    1990-01-01

    Surface emitting lasers are laterally aligned and coupled together and also have their light output signals combined. This results in greater phase and frequency coherency and narrower and reduced amplitude sidelobes. Preferably, not more than two lasers are longitudinally aligned along the same axis for still greater coherency compared with adding the light output signals of more than two longitudinally aligned lasers. The lasers can be of the DH-LOC type or of the QW type.

  2. Polarization-maintaining amplifier based on 3C fiber structures

    NASA Astrophysics Data System (ADS)

    Enokidani, Jun; Ito, Rumi; Sakurai, Tsutomu; Shin, Sumida; Tei, Kazuyoku

    2015-03-01

    Chirally-Coupled-Core (3C) fiber structure can preserve a single mode quality and even a linear polarization for a large core size. A principal advantage of fiber laser is its compatibility with monolithic integration and robust system. But so far, devices such as a combiner using the 3C fibers have not been reported. Here we report the first demonstration of such monolithic amplifier structure which contains an active fiber and a combiner based on 3C fibers. A single-stage amplifier is seeded by an EO Q-switched micro-laser and pumped by two high power fiber pigtailed 976-nm laser diodes via an in-house fabricated (2 + 1) × 1 pump signal combiner. The active fiber is based on a 3-m-long, 3C Yb-doped fiber (33 μm/250 μm core/cladding diameter with 0.06/0.46 NA). The amplifier demonstrates scaling up to 30W average power and 150 kW peak power in 0.3mJ, 2ns pulses. The beam profiles and beam qualities were characterized as its output power was varied up to 30W. The beam profile was maintained at a high beam quality of around M2=1.2. The spectral properties of the 3C fiber were also characterized as its output peak power was varied.

  3. [Tolerance of +Gz accelerations in chronic compensated cardiac muscle disease].

    PubMed

    Suvorov, P M; Bykova, Iu I

    1975-01-01

    The functional potentialities of the cardiovascular system were investigated during an exposure of people with compensated chronic diseases of the cardiac muscle to acceleration (+Gz). The test subjects were exposed to acceleration of 3 and 5 g for 30 sec with an interval of 5 min. The parameters of hemodynamics, ECG and visual perception were recorded. The systolic blood volume, cardiac output and specific peripheral resistance were derived from the Bremser-Ranke formula. Seventy one subjects with heart diseases and 23 healthy subjects were examined. The subjects with myocardiodystrophy and myocarditic cardiosclerosis (12+/-16) showed a reduced tolerance to accelerations. During an exposure the subjects with atherosclerotic cardiosclerosis showed a higher pressure in vessels of ear conch than the healthy subjects. The myocardiodystrophic subjects frequently (20%) exhibited an inversion of electrocardiographic T2. The subjects with heart diseases (27-33%) showed extrasystolic disturbances. The results may be used in medical expertise of pilots. PMID:1214489

  4. Influence of vascular function and pulsatile hemodynamics on cardiac function.

    PubMed

    Bell, Vanessa; Mitchell, Gary F

    2015-09-01

    Interactions between cardiac and vascular structure and function normally are optimized to ensure delivery of cardiac output with modest pulsatile hemodynamic overhead. Aortic stiffening with age or disease impairs optimal ventricular-vascular coupling, increases pulsatile load, and contributes to left ventricular (LV) hypertrophy, reduced systolic function, and impaired diastolic relaxation. Aortic pulse pressure and timing of peak systolic pressure are well-known measures of hemodynamic ventricular-vascular interaction. Recent work has elucidated the importance of direct, mechanical coupling between the aorta and the heart. LV systolic contraction results in displacement of aortic and mitral annuli, thereby producing longitudinal stretch in the ascending aorta and left atrium, respectively. Force associated with longitudinal stretch increases systolic load on the LV. However, the resulting energy stored in the elastic elements of the proximal aorta during systole facilitates early diastolic LV recoil and rapid filling. This review discusses current views on hemodynamics and mechanics of ventricular-vascular coupling. PMID:26164466

  5. Generalized Hash Chain Traversal with Selective Output

    NASA Astrophysics Data System (ADS)

    Yum, Dae Hyun; Seo, Jae Woo; Cho, Kookrae; Lee, Pil Joong

    A hash chain H for a one-way hash function h(·) is a sequence of hash values < v0, v1, . . . , vn >, where v0 is a public value, vn a secret value, and vi =h(vi+1). A hash chain traversal algorithm T computes and outputs the hash chain H, returning vi in time period (called round) i for 1 ≤ i ≤ n. While previous hash chain traversal algorithms were designed to output all hash values vi (1 ≤ i ≤ n) in order, there are applications where every m-th hash value (i.e., vm, v2m, v3m, . . .) is required to be output. We introduce a hash chain traversal algorithm that selectively outputs every m-th hash value efficiently. The main technique is a transformation from a hash chain traversal algorithm outputting every hash value into that outputting every m-th hash value. Compared with the direct use of previous hash chain traversal algorithms, our proposed method requires less memory storages and computational costs.

  6. Unstable resonator with reduced output coupling.

    PubMed

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Grünewald, Karin Maria; Handke, Jürgen

    2012-06-20

    The properties of a laser beam coupled out of a standard unstable laser resonator are heavily dependent on the chosen resonator magnification. A higher magnification results in a higher output coupling and a better beam quality. But in some configurations, an unstable resonator with a low output coupling in combination with a good beam quality is desirable. In order to reduce the output coupling for a particular resonator, magnification fractions of the outcoupled radiation are reflected back into the cavity. In the confocal case, the output mirror consists of a spherical inner section with a high reflectivity and a flat outer section with a partial reflectivity coating. With the application of the unstable resonator with reduced output coupling (URROC), magnification and output coupling can be adjusted independently from each other and it is possible to get a good beam quality and a high power extraction for lasers with a large low gain medium. The feasibility of this resonator design is examined numerically and experimentally with the help of a chemical oxygen iodine laser. PMID:22722301

  7. The transcription factor GATA-6 regulates pathological cardiac hypertrophy

    PubMed Central

    van Berlo, Jop H.; Elrod, John W.; van den Hoogenhof, Maarten M.G.; York, Allen J.; Aronow, Bruce J.; Duncan, Stephen A.; Molkentin, Jeffery D.

    2010-01-01

    Rationale The transcriptional code that programs maladaptive cardiac hypertrophy involves the zinc finger-containing DNA binding factor GATA-4. The highly related transcription factor GATA-6 is also expressed in the adult heart, although its role in controlling the hypertrophic program is unknown. Objective To determine the role of GATA-6 in cardiac hypertrophy and homeostasis. Methods and Results Here we performed a cardiomyocyte-specific conditional gene targeting approach for Gata6, as well as a transgenic approach to overexpress GATA-6 in the mouse heart. Deletion of Gata6-loxP with Nkx2.5-cre produced late embryonic lethality with heart defects, while deletion with β-myosin heavy chain-cre (βMHC-cre) produced viable adults with greater than 95% loss of GATA-6 protein in the heart. These later mice were subjected to pressure overload induced hypertrophy for 2 and 6 weeks, which showed a significant reduction in cardiac hypertrophy similar to that observed Gata4 heart-specific deleted mice. Gata6-deleted mice subjected to pressure overload also developed heart failure while control mice maintained proper cardiac function. Gata6-deleted mice also developed less cardiac hypertrophy following 2 weeks of angiotensin II/phenylephrine infusion. Controlled GATA-6 overexpression in the heart induced hypertrophy with aging and predisposed to greater hypertrophy with pressure overload stimulation. Combinatorial deletion of Gata4 and Gata6 from the adult heart resulted in dilated cardiomyopathy and lethality by 16 weeks of age. Mechanistically, deletion of Gata6 from the heart resulted in fundamental changes in the levels of key regulatory genes and myocyte differentiation-specific genes. Conclusions These results indicate that GATA-6 is both necessary and sufficient for regulating the cardiac hypertrophic response and differentiated gene expression, both alone and in coordination with GATA-4. PMID:20705924

  8. Constitutive phosphorylation of cardiac myosin regulatory light chain in vivo.

    PubMed

    Chang, Audrey N; Battiprolu, Pavan K; Cowley, Patrick M; Chen, Guohua; Gerard, Robert D; Pinto, Jose R; Hill, Joseph A; Baker, Anthony J; Kamm, Kristine E; Stull, James T

    2015-04-24

    In beating hearts, phosphorylation of myosin regulatory light chain (RLC) at a single site to 0.45 mol of phosphate/mol by cardiac myosin light chain kinase (cMLCK) increases Ca(2+) sensitivity of myofilament contraction necessary for normal cardiac performance. Reduction of RLC phosphorylation in conditional cMLCK knock-out mice caused cardiac dilation and loss of cardiac performance by 1 week, as shown by increased left ventricular internal diameter at end-diastole and decreased fractional shortening. Decreased RLC phosphorylation by conventional or conditional cMLCK gene ablation did not affect troponin-I or myosin-binding protein-C phosphorylation in vivo. The extent of RLC phosphorylation was not changed by prolonged infusion of dobutamine or treatment with a β-adrenergic antagonist, suggesting that RLC is constitutively phosphorylated to maintain cardiac performance. Biochemical studies with myofilaments showed that RLC phosphorylation up to 90% was a random process. RLC is slowly dephosphorylated in both noncontracting hearts and isolated cardiac myocytes from adult mice. Electrically paced ventricular trabeculae restored RLC phosphorylation, which was increased to 0.91 mol of phosphate/mol of RLC with inhibition of myosin light chain phosphatase (MLCP). The two RLCs in each myosin appear to be readily available for phosphorylation by a soluble cMLCK, but MLCP activity limits the amount of constitutive RLC phosphorylation. MLCP with its regulatory subunit MYPT2 bound tightly to myofilaments was constitutively phosphorylated in beating hearts at a site that inhibits MLCP activity. Thus, the constitutive RLC phosphorylation is limited physiologically by low cMLCK activity in balance with low MLCP activity. PMID:25733667

  9. Cardiac responses to hypoxia and reoxygenation in Drosophila.

    PubMed

    Zarndt, Rachel; Piloto, Sarah; Powell, Frank L; Haddad, Gabriel G; Bodmer, Rolf; Ocorr, Karen

    2015-12-01

    An adequate supply of oxygen is important for the survival of all tissues, but it is especially critical for tissues with high-energy demands, such as the heart. Insufficient tissue oxygenation occurs under a variety of conditions, including high altitude, embryonic and fetal development, inflammation, and thrombotic diseases, often affecting multiple organ systems. Responses and adaptations of the heart to hypoxia are of particular relevance in human cardiovascular and pulmonary diseases, in which the effects of hypoxic exposure can range in severity from transient to long-lasting. This study uses the genetic model system Drosophila to investigate cardiac responses to acute (30 min), sustained (18 h), and chronic (3 wk) hypoxia with reoxygenation. Whereas hearts from wild-type flies recovered quickly after acute hypoxia, exposure to sustained or chronic hypoxia significantly compromised heart function upon reoxygenation. Hearts from flies with mutations in sima, the Drosophila homolog of the hypoxia-inducible factor alpha subunit (HIF-α), exhibited exaggerated reductions in cardiac output in response to hypoxia. Heart function in hypoxia-selected flies, selected over many generations for survival in a low-oxygen environment, revealed reduced cardiac output in terms of decreased heart rate and fractional shortening compared with their normoxia controls. Hypoxia-selected flies also had smaller hearts, myofibrillar disorganization, and increased extracellular collagen deposition, consistent with the observed reductions in contractility. This study indicates that longer-duration hypoxic insults exert deleterious effects on heart function that are mediated, in part, by sima and advances Drosophila models for the genetic analysis of cardiac-specific responses to hypoxia and reoxygenation. PMID:26377557

  10. Parkin-independent mitophagy requires Drp1 and maintains the integrity of mammalian heart and brain.

    PubMed

    Kageyama, Yusuke; Hoshijima, Masahiko; Seo, Kinya; Bedja, Djahida; Sysa-Shah, Polina; Andrabi, Shaida A; Chen, Weiran; Hke, Ahmet; Dawson, Valina L; Dawson, Ted M; Gabrielson, Kathleen; Kass, David A; Iijima, Miho; Sesaki, Hiromi

    2014-12-01

    Mitochondrial dynamics and mitophagy have been linked to cardiovascular and neurodegenerative diseases. Here, we demonstrate that the mitochondrial division dynamin Drp1 and the Parkinson's disease-associated E3 ubiquitin ligase parkin synergistically maintain the integrity of mitochondrial structure and function in mouse heart and brain. Mice lacking cardiac Drp1 exhibited lethal heart defects. In Drp1KO cardiomyocytes, mitochondria increased their connectivity, accumulated ubiquitinated proteins, and decreased their respiration. In contrast to the current views of the role of parkin in ubiquitination of mitochondrial proteins, mitochondrial ubiquitination was independent of parkin in Drp1KO hearts, and simultaneous loss of Drp1 and parkin worsened cardiac defects. Drp1 and parkin also play synergistic roles in neuronal mitochondrial homeostasis and survival. Mitochondrial degradation was further decreased by combination of Drp1 and parkin deficiency, compared with their single loss. Thus, the physiological importance of parkin in mitochondrial homeostasis is revealed in the absence of mitochondrial division in mammals. PMID:25349190

  11. Parkin-independent mitophagy requires Drp1 and maintains the integrity of mammalian heart and brain

    PubMed Central

    Kageyama, Yusuke; Hoshijima, Masahiko; Seo, Kinya; Bedja, Djahida; Sysa-Shah, Polina; Andrabi, Shaida A; Chen, Weiran; Höke, Ahmet; Dawson, Valina L; Dawson, Ted M; Gabrielson, Kathleen; Kass, David A; Iijima, Miho; Sesaki, Hiromi

    2014-01-01

    Mitochondrial dynamics and mitophagy have been linked to cardiovascular and neurodegenerative diseases. Here, we demonstrate that the mitochondrial division dynamin Drp1 and the Parkinson's disease-associated E3 ubiquitin ligase parkin synergistically maintain the integrity of mitochondrial structure and function in mouse heart and brain. Mice lacking cardiac Drp1 exhibited lethal heart defects. In Drp1KO cardiomyocytes, mitochondria increased their connectivity, accumulated ubiquitinated proteins, and decreased their respiration. In contrast to the current views of the role of parkin in ubiquitination of mitochondrial proteins, mitochondrial ubiquitination was independent of parkin in Drp1KO hearts, and simultaneous loss of Drp1 and parkin worsened cardiac defects. Drp1 and parkin also play synergistic roles in neuronal mitochondrial homeostasis and survival. Mitochondrial degradation was further decreased by combination of Drp1 and parkin deficiency, compared with their single loss. Thus, the physiological importance of parkin in mitochondrial homeostasis is revealed in the absence of mitochondrial division in mammals. PMID:25349190

  12. Cardiac catheterization and angiography. Third edition

    SciTech Connect

    Grossman, W.

    1986-01-01

    This book discusses the papers on cardiac catheterization and angiography. The topics covered are: historical perspective and present practice of cardiac catheterization; angiography principles and utilization of radiologic and cineangiographic equipment; complications, incidence and prevention of side effects of cardiac catheterization; techniques; blood flow measurement of heart; pressure measurement; diagnostic techniques of angiography; special catheter techniques; coronary angiography, temporary and permanent pacemakers, potential role of lasers in the cardiac catheterization and evaluation of cardiac function.

  13. Constancy and variability in the output of a central pattern generator.

    PubMed

    Norris, Brian J; Wenning, Angela; Wright, Terrence Michael; Calabrese, Ronald L

    2011-03-23

    Experimental and corresponding modeling studies have demonstrated a twofold to fivefold variation of intrinsic and synaptic parameters across animals, whereas functional output is maintained. These studies have led to the hypothesis that correlated, compensatory changes in particular parameters can at least partially explain the biological variability in parameters. Using the leech heartbeat central pattern generator (CPG), we selected three different segmental motor neurons that fire in a functional phase progression but receive input from the same four premotor interneurons. Previous work suggested that the phase progression arises because the pattern of relative strength of the four inputs varies systematically across the segmental motor neurons. Nevertheless, there was considerable animal-to-animal variation in the absolute strengths of these connections. We tested the hypothesis that functional output is maintained in the face of variation in the absolute strength of connections because relative strengths onto particular motor neurons are maintained. We found that relative strength is not strictly maintained across animals even as functional output is maintained, and animal-to-animal variations in relative strength of particular inputs do not correlate strongly with output phase. In parallel with this variation in synaptic strength, the firing phase of the premotor inputs to these motor neurons varies considerably across individuals. We conclude that the number (four) of inputs to each motor neuron, which each vary in strength, and the phase diversity of the temporal pattern of input from the CPG diminish the influence of individual inputs. We hypothesize that each animal arrives at a unique solution for how the network produces functional output. PMID:21430165

  14. Robot-assisted cardiac surgery.

    PubMed

    Ishikawa, Norihiko; Watanabe, Go

    2015-01-01

    Recognition of the significant advantages of minimizing surgical trauma has resulted in the development of minimally invasive surgical procedures. Endoscopic surgery offers patients the benefits of minimally invasive surgery, and surgical robots have enhanced the ability and precision of surgeons. Consequently, technological advances have facilitated totally endoscopic robotic cardiac surgery, which has allowed surgeons to operate endoscopically rather than through a median sternotomy during cardiac surgery. Thus, repairs for structural heart conditions, including mitral valve plasty, atrial septal defect closure, multivessel minimally invasive direct coronary artery bypass grafting (MIDCAB), and totally endoscopic coronary artery bypass graft surgery (CABG), can be totally endoscopic. Robot-assisted cardiac surgery as minimally invasive cardiac surgery is reviewed. PMID:26134073

  15. Cardiac Fibrosis: The Fibroblast Awakens.

    PubMed

    Travers, Joshua G; Kamal, Fadia A; Robbins, Jeffrey; Yutzey, Katherine E; Blaxall, Burns C

    2016-03-18

    Myocardial fibrosis is a significant global health problem associated with nearly all forms of heart disease. Cardiac fibroblasts comprise an essential cell type in the heart that is responsible for the homeostasis of the extracellular matrix; however, upon injury, these cells transform to a myofibroblast phenotype and contribute to cardiac fibrosis. This remodeling involves pathological changes that include chamber dilation, cardiomyocyte hypertrophy and apoptosis, and ultimately leads to the progression to heart failure. Despite the critical importance of fibrosis in cardiovascular disease, our limited understanding of the cardiac fibroblast impedes the development of potential therapies that effectively target this cell type and its pathological contribution to disease progression. This review summarizes current knowledge regarding the origins and roles of fibroblasts, mediators and signaling pathways known to influence fibroblast function after myocardial injury, as well as novel therapeutic strategies under investigation to attenuate cardiac fibrosis. PMID:26987915

  16. HL-1 cells: A cardiac muscle cell line that contracts and retains phenotypic characteristics of the adult cardiomyocyte

    PubMed Central

    Claycomb, William C.; Lanson, Nicholas A.; Stallworth, Beverly S.; Egeland, Daniel B.; Delcarpio, Joseph B.; Bahinski, Anthony; Izzo, Nicholas J.

    1998-01-01

    We have derived a cardiac muscle cell line, designated HL-1, from the AT-1 mouse atrial cardiomyocyte tumor lineage. HL-1 cells can be serially passaged, yet they maintain the ability to contract and retain differentiated cardiac morphological, biochemical, and electrophysiological properties. Ultrastructural characteristics typical of embryonic atrial cardiac muscle cells were found consistently in the cultured HL-1 cells. Reverse transcriptase–PCR-based analyses confirmed a pattern of gene expression similar to that of adult atrial myocytes, including expression of α-cardiac myosin heavy chain, α-cardiac actin, and connexin43. They also express the gene for atrial natriuretic factor. Immunohistochemical staining of the HL-1 cells indicated that the distribution of the cardiac-specific markers desmin, sarcomeric myosin, and atrial natriuretic factor was similar to that of cultured atrial cardiomyocytes. A delayed rectifier potassium current (IKr) was the most prominent outward current in HL-1 cells. The activating currents displayed inward rectification and deactivating current tails were voltage-dependent, saturated at ≫+20 mV, and were highly sensitive to dofetilide (IC50 of 46.9 nM). Specific binding of [3H]dofetilide was saturable and fit a one-site binding isotherm with a Kd of 140 +/− 60 nM and a Bmax of 118 fmol per 105 cells. HL-1 cells represent a cardiac myocyte cell line that can be repeatedly passaged and yet maintain a cardiac-specific phenotype. PMID:9501201

  17. Cardiac manifestations in systemic sclerosis.

    PubMed

    Lambova, Sevdalina

    2014-09-26

    Primary cardiac involvement, which develops as a direct consequence of systemic sclerosis (SSc), may manifest as myocardial damage, fibrosis of the conduction system, pericardial and, less frequently, as valvular disease. In addition, cardiac complications in SSc may develop as a secondary phenomenon due to pulmonary arterial hypertension and kidney pathology. The prevalence of primary cardiac involvement in SSc is variable and difficult to determine because of the diversity of cardiac manifestations, the presence of subclinical periods, the type of diagnostic tools applied, and the diversity of patient populations. When clinically manifested, cardiac involvement is thought to be an important prognostic factor. Profound microvascular disease is a pathognomonic feature of SSc, as both vasospasm and structural alterations are present. Such alterations are thought to predict macrovascular atherosclerosis over time. There are contradictory reports regarding the prevalence of atherosclerosis in SSc. According to some authors, the prevalence of atherosclerosis of the large epicardial coronary arteries is similar to that of the general population, in contrast with other rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, the level of inflammation in SSc is inferior. Thus, the atherosclerotic process may not be as aggressive and not easily detectable in smaller studies. Echocardiography (especially tissue Doppler imaging), single-photon emission computed tomography, magnetic resonance imaging and cardiac computed tomography are sensitive techniques for earlier detection of both structural and functional scleroderma-related cardiac pathologies. Screening for subclinical cardiac involvement via modern, sensitive tools provides an opportunity for early diagnosis and treatment, which is of crucial importance for a positive outcome. PMID:25276300

  18. Cardiac manifestations in systemic sclerosis

    PubMed Central

    Lambova, Sevdalina

    2014-01-01

    Primary cardiac involvement, which develops as a direct consequence of systemic sclerosis (SSc), may manifest as myocardial damage, fibrosis of the conduction system, pericardial and, less frequently, as valvular disease. In addition, cardiac complications in SSc may develop as a secondary phenomenon due to pulmonary arterial hypertension and kidney pathology. The prevalence of primary cardiac involvement in SSc is variable and difficult to determine because of the diversity of cardiac manifestations, the presence of subclinical periods, the type of diagnostic tools applied, and the diversity of patient populations. When clinically manifested, cardiac involvement is thought to be an important prognostic factor. Profound microvascular disease is a pathognomonic feature of SSc, as both vasospasm and structural alterations are present. Such alterations are thought to predict macrovascular atherosclerosis over time. There are contradictory reports regarding the prevalence of atherosclerosis in SSc. According to some authors, the prevalence of atherosclerosis of the large epicardial coronary arteries is similar to that of the general population, in contrast with other rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, the level of inflammation in SSc is inferior. Thus, the atherosclerotic process may not be as aggressive and not easily detectable in smaller studies. Echocardiography (especially tissue Doppler imaging), single-photon emission computed tomography, magnetic resonance imaging and cardiac computed tomography are sensitive techniques for earlier detection of both structural and functional scleroderma-related cardiac pathologies. Screening for subclinical cardiac involvement via modern, sensitive tools provides an opportunity for early diagnosis and treatment, which is of crucial importance for a positive outcome. PMID:25276300

  19. Cardiac effects of noncardiac neoplasms

    SciTech Connect

    Schoen, F.J.; Berger, B.M.; Guerina, N.G.

    1984-11-01

    Clinically significant cardiovascular abnormalities may occur as secondary manifestations of noncardiac neoplasms. The principal cardiac effects of noncardiac tumors include the direct results of metastases to the heart or lungs, the indirect effects of circulating tumor products (causing nonbacterial thrombotic endocarditis, myeloma-associated amyloidosis, pheochromocytoma-associated cardiac hypertrophy and myofibrillar degeneration, and carcinoid heart disease), and the undesired cardiotoxicities of chemotherapy and radiotherapy. 89 references.

  20. Gene Transfer into Cardiac Myocytes

    PubMed Central

    Lang, Sarah E.; Westfall, Margaret V.

    2016-01-01

    Traditional methods for DNA transfection are often inefficient and toxic for terminally differentiated cells, such as cardiac myocytes. Vector-based gene transfer is an efficient approach for introducing exogenous cDNA into these types of primary cell cultures. In this chapter, separate protocols for adult rat cardiac myocyte isolation and gene transfer with recombinant adenovirus are provided and are routinely utilized for studying the effects of sarcomeric proteins on myofilament function. PMID:25836585