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Sample records for maintain cardiac output

  1. Cardiac output during human sleep.

    PubMed

    Miller, J C; Horvath, S M

    1976-10-01

    Impedance cardiogram and sleep EEG were recorded from four male and four female subjects, aged 21 to 22 years, during one night in the laboratory following one adaptation night. Cardiac output fell approximately 26% during the night as a consequence of diminished stroke volume, the lowest values of both occurring during the latter portion of the night, dominated by SREM (rapid-eye-movement stage). Intracycle comparisons between SREM and SWS (slow wave sleep) or between eye movement burst and non-burst SREM showed no significant differences in stroke volume or cardiac output. Pre-ejection period and systolic ejection period were measured and discussed. The non-coincidence of the nadir of metabolic activity, expressed as cardiac output, and the apex of slow-wave sleep activity supported the concept of slow-wave sleep as a period of physiological restoration.

  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. New electrical plethysmograph monitors cardiac output

    NASA Technical Reports Server (NTRS)

    Kubicek, W. B.; Patterson, R. P.; Witsoe, D. A.

    1968-01-01

    Four-electrode impedance plethysmograph measures ventricular stroke volume of cardiac output of humans. The instrument is automatic, operates with only one recording channel, and minimizes patient discomfort.

  4. Cardiac output: a view from Buffalo.

    PubMed

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

    2003-10-01

    Cardiac output (Q) is a primary determinant of blood pressure and O2 delivery and is critical in the maintenance of homeostasis, particularly during environmental stress. Cardiac output can be determined invasively in patients; however, indirect methods are required for other situations. Soluble gas techniques are widely used to determine Q. Historically, measurements during a breathhold, prolonged expiration and rebreathing to CO2 equilibrium have been used; however, with limitations, especially during stress. Farhi and co-workers developed a single-step CO2 rebreathing method, which was subsequently revised by his group, and has been shown to be valid (compared to direct measures) and reliable. Carbon dioxide output (VCO2), partial pressure of arterial CO2 (PaCO2), and partial pressure of mixed venous CO2 (Pv(CO2)) are determined during 12-25 s of rebreathing, using the appropriate tidal volume, and Q is calculated. This method has the utility to provide accurate data in laboratory and field experiments during exercise, increased and micro-gravity, water immersion, lower body pressure, head-down tilt, and changes in gas composition and pressure. Utilizing the Buffalo CO2 rebreathing method it has been shown that the Q can adjust to a wide range of changes in environments maintaining blood pressure and O2 delivery at rest and during exercise.

  5. William Harvey, Peter Lauremberg and cardiac output.

    PubMed

    Teichmann, G

    1992-11-01

    In 1636, the Rostock professor of medicine and the art of poetry, Peter Lauremberg (1585-1639), was one of the earliest to mention circulation which had been discovered by William Harvey and documented in his anatomical manual. In 1628 William Harvey proved the existence of the blood circulation by calculating the "cardiac output in a half an hour (semihora)". The answer to the question why Harvey chose half an hour as the time range can be found in the way of measuring time usual at that period. The sandglasses were turned half-hourly in maritime navigation and the wheel-clocks on shore had only the hour-hand. Improved chronometry was one of the prerequisites for measuring cardiac output. The minute-hand became usual after 1700 and the second-hand later on. Taking into consideration the alterations of cardiac output made the latter one of the most important circulation parameters in diagnostics, prognostication and therapeutics.

  6. [Cardiac output monitoring by impedance cardiography in cardiac surgery].

    PubMed

    Shimizu, H; Seki, S; Mizuguchi, A; Tsuchida, H; Watanabe, H; Namiki, A

    1990-04-01

    The cardiac output monitoring by impedance cardiography, NCCOM3, was evaluated in adult patients (n = 12) who were subjected to coronary artery bypass grafting. Values of cardiac output measured by impedance cardiography were compared to those by the thermodilution method. Changes of base impedance level used as an index of thoracic fluid volume were also investigated before and after cardiopulmonary bypass (CPB). Correlation coefficient (r) of the values obtained by thermodilution with impedance cardiography was 0.79 and the mean difference was 1.29 +/- 16.9 (SD)% during induction of anesthesia. During the operation, r was 0.83 and the mean difference was -14.6 +/- 18.7%. The measurement by impedance cardiography could be carried out through the operation except when electro-cautery was used. Base impedance level before CPB was significantly lower as compared with that after CPB. There was a negative correlation between the base impedance level and central venous pressure (CVP). No patients showed any signs suggesting lung edema and all the values of CVP, pulmonary artery pressure and blood gas analysis were within normal ranges. From the result of this study, it was concluded that cardiac output monitoring by impedance cardiography was useful in cardiac surgery, but further detailed examinations will be necessary on the relationship between the numerical values of base impedance and the clinical state of the patients. PMID:2362347

  7. 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.

  8. Modelflow underestimates cardiac output in heat-stressed individuals

    PubMed Central

    Shibasaki, Manabu; Wilson, Thad E.; Bundgaard-Nielsen, Morten; Seifert, Thomas; Secher, Niels H.

    2011-01-01

    An estimation of cardiac output can be obtained from arterial pressure waveforms using the Modelflow method. However, whether the assumptions associated with Modelflow calculations are accurate during whole body heating is unknown. This project tested the hypothesis that cardiac output obtained via Modelflow accurately tracks thermodilution-derived cardiac outputs during whole body heat stress. Acute changes of cardiac output were accomplished via lower-body negative pressure (LBNP) during normothermic and heat-stressed conditions. In nine healthy normotensive subjects, arterial pressure was measured via brachial artery cannulation and the volume-clamp method of the Finometer. Cardiac output was estimated from both pressure waveforms using the Modeflow method. In normothermic conditions, cardiac outputs estimated via Modelflow (arterial cannulation: 6.1 ± 1.0 l/min; Finometer 6.3 ± 1.3 l/min) were similar with cardiac outputs measured by thermodilution (6.4 ± 0.8 l/min). The subsequent reduction in cardiac output during LBNP was also similar among these methods. Whole body heat stress elevated internal temperature from 36.6 ± 0.3 to 37.8 ± 0.4°C and increased cardiac output from 6.4 ± 0.8 to 10.9 ± 2.0 l/min when evaluated with thermodilution (P < 0.001). However, the increase in cardiac output estimated from the Modelflow method for both arterial cannulation (2.3 ± 1.1 l/min) and Finometer (1.5 ± 1.2 l/min) was attenuated compared with thermodilution (4.5 ± 1.4 l/min, both P < 0.01). Finally, the reduction in cardiac output during LBNP while heat stressed was significantly attenuated for both Modelflow methods (cannulation: −1.8 ± 1.2 l/min, Finometer: −1.5 ± 0.9 l/min) compared with thermodilution (−3.8 ± 1.19 l/min). These results demonstrate that the Modelflow method, regardless of Finometer or direct arterial waveforms, underestimates cardiac output during heat stress and during subsequent reductions in cardiac output via LBNP. PMID

  9. Issues in methods and measurement of thermodilution cardiac output.

    PubMed

    Sommers, M S; Woods, S L; Courtade, M A

    1993-01-01

    Criterion-related validity of the thermodilution cardiac output technique for cardiac output measurement has to have a high correlation (r = .91 to .98) with the direct Fick method, the gold standard of cardiac output measurement. Issues that can affect validity of the measurements include the position of the pulmonary artery catheter, the rate of injection of the indicator solution, the volume and temperature of the injectate, the timing of the injection of indicator solution during the respiratory cycle, the position of the subject, and the presence of concomitant infusions. Variation in measurement can be limited by considering the delivery system for the indicator solution, by recording time-temperature cardiac output curves, and by considering normal biologic variations. PMID:8337161

  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. Volume and its relationship to cardiac output and venous return.

    PubMed

    Magder, S

    2016-01-01

    Volume infusions are one of the commonest clinical interventions in critically ill patients yet the relationship of volume to cardiac output is not well understood. Blood volume has a stressed and unstressed component but only the stressed component determines flow. It is usually about 30 % of total volume. Stressed volume is relatively constant under steady state conditions. It creates an elastic recoil pressure that is an important factor in the generation of blood flow. The heart creates circulatory flow by lowering the right atrial pressure and allowing the recoil pressure in veins and venules to drain blood back to the heart. The heart then puts the volume back into the systemic circulation so that stroke return equals stroke volume. The heart cannot pump out more volume than comes back. Changes in cardiac output without changes in stressed volume occur because of changes in arterial and venous resistances which redistribute blood volume and change pressure gradients throughout the vasculature. Stressed volume also can be increased by decreasing vascular capacitance, which means recruiting unstressed volume into stressed volume. This is the equivalent of an auto-transfusion. It is worth noting that during exercise in normal young males, cardiac output can increase five-fold with only small changes in stressed blood volume. The mechanical characteristics of the cardiac chambers and the circulation thus ultimately determine the relationship between volume and cardiac output and are the subject of this review. PMID:27613307

  12. Volume and its relationship to cardiac output and venous return.

    PubMed

    Magder, S

    2016-09-10

    Volume infusions are one of the commonest clinical interventions in critically ill patients yet the relationship of volume to cardiac output is not well understood. Blood volume has a stressed and unstressed component but only the stressed component determines flow. It is usually about 30 % of total volume. Stressed volume is relatively constant under steady state conditions. It creates an elastic recoil pressure that is an important factor in the generation of blood flow. The heart creates circulatory flow by lowering the right atrial pressure and allowing the recoil pressure in veins and venules to drain blood back to the heart. The heart then puts the volume back into the systemic circulation so that stroke return equals stroke volume. The heart cannot pump out more volume than comes back. Changes in cardiac output without changes in stressed volume occur because of changes in arterial and venous resistances which redistribute blood volume and change pressure gradients throughout the vasculature. Stressed volume also can be increased by decreasing vascular capacitance, which means recruiting unstressed volume into stressed volume. This is the equivalent of an auto-transfusion. It is worth noting that during exercise in normal young males, cardiac output can increase five-fold with only small changes in stressed blood volume. The mechanical characteristics of the cardiac chambers and the circulation thus ultimately determine the relationship between volume and cardiac output and are the subject of this review.

  13. 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.

  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. Revised one-step method for determination of cardiac output.

    PubMed

    Olszowka, A J; Shykoff, B E; Pendergast, D R; Farhi, L E

    2004-04-20

    Cardiac output (Q) is a determinant of blood pressure and O(2) delivery and is critical in the maintenance of homeostasis, particularly during environmental stress and exercise. Cardiac output can be determined invasively in patients; however, indirect methods are required for other situations. Soluble gas techniques are widely used to determine (Q). Historically, measurements during a breathhold, prolonged expiration and rebreathing to CO(2) equilibrium have been used; however, with limitations, especially during stress. Farhi and co-workers developed a single-step CO(2) rebreathing method, which was subsequently revised by his group, and has been shown to be reliable and compared closely to direct, invasive measures. V(CO2), P(ACO2), and P(VCO2) are determined during a 12-25s rebreathing, using the appropriate tidal volume, and (Q) is calculated. This method can provide accurate data in laboratory and field experiments during exercise, increased or decreased gravity, water immersion, lower body pressure, head-down tilt, altered ambient pressure or changes in inspired gas composition.

  16. Effect of isosorbide dinitrate on cardiac output in severe cardiac failure: relation to initial hemodynamics, ventricular volume, and the preload reserve mechanism.

    PubMed

    Lewis, B S; Hardoff, R; Halon, D A

    1989-09-01

    Isosorbide dinitrate (ISDN) improves the clinical and hemodynamic state of patients with heart failure, but may cause dizziness and syncope. To characterize patients in whom cardiac output falls with high-dose nitrate therapy and to examine further the pathophysiology of the fall in cardiac output in these patients, we studies the effect of sublingual ISDN on forward cardiac output in 14 patients with severe cardiac failure (New York Heart Association grades 3-4). We examined systolic and diastolic left ventricular (LV) function from pressure and volume analyses of LV function. After administration of 15 mg ISDN, cardiac output was either unaltered or increased in 7 patients (Group 1) (11 +/- 12%, mean +/- SD), and decreased in 7 (Group 2) (-13 +/- 10%) (Group 1 vs. 2, p less than 0.002). Initial systemic arterial pressure, LV ejection fraction, wedge and LV transmural filling pressures were similar in both groups, but Group 2 patients had a lower systemic vascular resistance (p = 0.07) and tended to have a larger initial LV end-diastolic volume and increased end-diastolic compliance; following ISDN the decrease in LV filling pressure and end-diastolic volume was larger and the product of the changes greater (p less than 0.02). Thus ISDN decreases filling pressure and improves forward cardiac output in some patients with congestive heart failure, but large doses may decrease cardiac output in a subset of patients who have a lower systemic vascular resistance and a larger more compliant ventricle, maintaining forward blood flow predominantly by a preload reserve mechanism.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2791373

  17. 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.

  18. A non-invasive method for measuring cardiac output: the effect of Christmas lunch.

    PubMed

    Cowley, A J; Stainer, K; Murphy, D T; Murphy, J; Hampton, J R

    Cardiac output was measured in ten patients at routine cardiac catheterisation and three patients with severe heart failure by means of a carbon dioxide rebreathing technique with a computer-assisted mass spectrometer and compared with cardiac output measured by thermodilution. There was a close correlation (r = 0.96, p less than 0.01) between the two methods. Cardiac output measured by the carbon dioxide rebreathing technique increased after a typical Christmas lunch by a mean of 1.6 1/min in a group of healthy volunteers.

  19. The relationship between cardiac output, cerebral electrical activity, cerebral fractional oxygen extraction and peripheral blood flow in premature newborn infants.

    PubMed

    Victor, Suresh; Appleton, Richard E; Beirne, Margaret; Marson, Anthony G; Weindling, A Michael

    2006-10-01

    Cardiac output is a determinant of systemic blood flow and its measurement may therefore be a useful indicator of abnormal hemodynamics and tissue oxygen delivery. The purpose of this study was to investigate in very premature newborn infants the relationships between cardiac output (left and right ventricular outputs), systemic blood pressure, peripheral blood flow (PBF) and two indicators of cerebral oxygen delivery (cerebral electrical activity and cerebral fractional oxygen extraction (CFOE)). This was a prospective observational study performed on 40 infants of less than 30 wk gestation. Digital electroencephalograms (EEGs) were recorded for one hour every day during the first four days after birth and subjected to qualitative and quantitative analysis. Left and right ventricular outputs, mean blood pressure (MBP), CFOE, PBF and arterial blood gases were measured at the same time. Within the ranges studied, there was no apparent relationship between left or right ventricular output (RVO), PBF and indicators of cerebral perfusion (cerebral electrical activity and CFOE). The EEG was normal in infants with low left and right ventricular outputs (<150 mL/kg/min) and MBP > 30 mm Hg. Infants with low cardiac output and normal MBP seem able to maintain cerebral perfusion, possibly through vasodilatation of the cerebral microvasculature. PMID:16940235

  20. Laser Doppler flowmetry and cardiac output in critically ill surgical patients.

    PubMed

    Eyer, S; Borgos, J; Strate, R G

    1987-08-01

    Laser Doppler flowmetry (LDF) accurately measures cutaneous microcirculatory blood flow. We compared change in LDF flow to change in thermodilution cardiac output in ten critically ill surgical patients. A subset analysis of three patients with low cardiac output (cardiac index less than 2 L/min X m2) showed no correlation. We conclude that, under these study conditions, LDF microcirculatory flow did not reflect macrocirculatory flow. We conjecture that overcoming cutaneous vasoregulation with thermal vasodilation may obviate these results.

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

    PubMed

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

    2014-08-01

    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

  2. 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

  3. Measurement of cardiac output by carbon dioxide rebreathing methods.

    PubMed

    Heigenhauser, G J; Jones, N L

    1989-06-01

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

  4. Validation of the qCO cardiac output monitor during Valsalva maneuver.

    PubMed

    Jospin, Mathieu; Aguilar, Juan P; Gambus, Pedro L; Jensen, Erik W; Vallverdu, Montserrat; Caminal, Pere

    2012-01-01

    Monitoring cardiac output for a variety of patient conditions is essential to ensure tissue perfusion and oxygenation. Cardiac output can be measured either invasively using a pulmonary artery catheter or non-invasively using impedance cardiography (ICG). The objective of the present study was to validate a cardiac output monitor, the qCO (Quantium Medical, Barcelona, Spain). The qCO is based on the ICG principle. Twenty-five volunteers (18-75 years) were enrolled in the study. The duration of the study was 10 min. The subjects were asked to rest quietly in an armchair for a duration of 5 min. At 5 min they were asked to do a Valsalva maneuver which is known to decrease the cardiac output. The baseline value of the normalized cardiac output (qCO index) was compared with the minimum value during the Valsalva maneuver. The results showed (t-test, p<0.0005) significant difference between the cardiac output estimated at baseline and during the Valsalva maneuver. In conclusion, the qCO was able to indicate trend changes of the cardiac output in volunteers.

  5. 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.

  6. Improvements in determination of cardiac output with a Swan-Ganz catheter.

    PubMed

    Sakagami, M; Kuwana, K; Nakanishi, H; Sakai, K

    1990-01-01

    The time constant for heat transfer may affect exact determination of cardiac output with Swan-Ganz catheters. Commercially available Swan-Ganz catheters are provided with thermistors with varying time constants. Current monitoring of cardiac output is not corrected for these time constants, so the conventional method of determining cardiac output using the equation of Stewart-Hamilton produces marked errors. The authors propose a new method of determining cardiac output with Swan-Ganz catheters with varying time constants from thermal dilution curve data based on Newton's cooling law. Values for blood flow rate determined by the new method using a completely stirred tank of original design, mimicking the natural heart and using bovine blood, are almost the same as values observed at varying saline infusion volumes, saline temperatures, and saline infusion times.

  7. Intensive insulin therapy to maintain normoglycemia after cardiac surgery.

    PubMed

    Van den Berghe, G

    2011-01-01

    Drugs used in the perioperative period could have an effect on survival as recently pointed out by an international consensus conference on the reduction in mortality in cardiac anesthesia and intensive care. Insulin infusion to achieve a strict glycemic control is the best example of how an ancillary (i.e. non-surgical) drug/technique/strategy might influence survival rates in patients undergoing cardiac surgery. The author of this "expert opinion" presents her insights into the use of insulin in this setting and suggest that based on available evidence based medicine, insulin infusion, titrated to "normoglycemia" is a complex intervention, that not only requires the simple administration of a "drug", the hormone insulin, but also needs tools and skills to accurately measure and control blood glucose to achieve normoglycemia while avoiding hypoglycemia and large glucose fluctuations. PMID:23439402

  8. Supranormal cardiac output in the dopamine- and dobutamine-dependent preterm infant.

    PubMed

    Lopez, S L; Leighton, J O; Walther, F J

    1997-01-01

    To evaluate the incidence of low cardiac output in preterm infants with respiratory distress syndrome (RDS), we measured cardiac output, stroke volume, heart rate, mean arterial blood pressure, and systemic vascular resistance at 8-48 hours of age in 30 preterm infants with RDS who were dependent on inotropic support. We then compared them to 23 normotensive preterm infants with RDS and 27 preterm infants without RDS. RDS infants had a higher cardiac output and lower systemic vascular resistance and blood pressure than infants without RDS. Infants treated with dopamine and dobutamine had a higher cardiac output and heart rate than infants on dopamine alone or the normotensive controls but a lower blood pressure and systemic vascular resistance than the normotensive controls. Supranormal cardiac output (>400 ml/min/kg) was detected in 57% of the infants in the dopamine + dobutamine subgroup (p = 0.009) versus 17% in the normotensive RDS subgroup and 12% in the dopamine subgroup. These data show that high cardiac output is relatively common in infants with RDS dependent on dopamine and dobutamine but is not reflected in the blood pressure.

  9. Validation of MRI measurement of cardiac output in the dog: the effects of dobutamine and minoxidil.

    PubMed

    Hockings, Paul D; Busza, Albert L; Byrne, Joanne; Patel, Bela; Smart, Sean C; Reid, David G; Lloyd, Heather L; White, Alan; Pointing, Karen; Farnfield, Belinda A; Criado-Gonzalez, Ana; Whelan, Greg A; Taylor, Gemma L; Birmingham, Jeffrey M; Slaughter, Mark R; Osborne, Janette A; Krebs-Brown, Axel; Templeton, David

    2003-01-01

    The use of magnetic resonance imaging (MRI) for the measurement of cardiac output parameters in anesthetized adult male beagle dogs has been validated against a widely accepted thermodilution method. Using a multislice cine gradient echo MRI method to acquire images of the entire heart, left ventricular lumen volumes were measured at systole and diastole in seven animals. Cardiac output correlated well (R 2 = 0.88) with thermodilution measurements made in a parallel manner, both before and during acute stimulation with the inotrope dobutamine. In a chronic study of changes in cardiac morphology and function brought about by the antihypertensive minoxidil, MRI reliably detected the expected increases in stroke volume (28%) and cardiac output (58%) resulting from neural reaction to decreased blood pressure. Left ventricular lumen enlarged as well in response to fluid retention and plasma volume increase. Two in four minoxidil-treated animals also developed clear MRI-visible pericardial effusion. PMID:20021181

  10. Evaluation of cardiac output by 5 arterial pulse contour techniques using trend interchangeability method

    PubMed Central

    Fischer, Marc-Olivier; Diouf, Momar; de Wilde, Robert B.P.; Dupont, Hervé; Hanouz, Jean-Luc; Lorne, Emmanuel

    2016-01-01

    Abstract Cardiac output measurement with pulse contour analysis is a continuous, mini-invasive, operator-independent, widely used, and cost-effective technique, which could be helpful to assess changes in cardiac output. The 4-quadrant plot and the polar plot have been described to compare the changes between 2 measurements performed under different conditions, and the direction of change by using different methods of measurements. However, the 4-quadrant plot and the polar plot present a number of limitations, with a risk of misinterpretation in routine clinical practice. We describe a new trend interchangeability method designed to objectively define the interchangeability of each change of a variable. Using the repeatability of the reference method, we classified each change as either uninterpretable or interpretable and then as either noninterchangeable, in the gray zone or interchangeable. An interchangeability rate can then be calculated by the number of interchangeable changes divided by the total number of interpretable changes. In this observational study, we used this objective method to assess cardiac output changes with 5 arterial pulse contour techniques (Wesseling's method, LiDCO, PiCCO, Hemac method, and Modelflow) in comparison with bolus thermodilution technique as reference method in 24 cardiac surgery patients. A total of 172 cardiac output variations were available from the 199 data points: 88 (51%) were uninterpretable, according to the first step of the method. The second step of the method, based on the 84 (49%) interpretable variations, showed that only 18 (21%) to 30 (36%) variations were interchangeable regardless of the technique used. None of pulse contour cardiac output technique could be interchangeable with bolus thermodilution to assess changes in cardiac output using the trend interchangeability method in cardiac surgery patients. Future studies may consider using this method to assess interchangeability of changes between different

  11. Evaluation of cardiac output by 5 arterial pulse contour techniques using trend interchangeability method.

    PubMed

    Fischer, Marc-Olivier; Diouf, Momar; Wilde, Robert B P de; Dupont, Hervé; Hanouz, Jean-Luc; Lorne, Emmanuel

    2016-06-01

    Cardiac output measurement with pulse contour analysis is a continuous, mini-invasive, operator-independent, widely used, and cost-effective technique, which could be helpful to assess changes in cardiac output. The 4-quadrant plot and the polar plot have been described to compare the changes between 2 measurements performed under different conditions, and the direction of change by using different methods of measurements. However, the 4-quadrant plot and the polar plot present a number of limitations, with a risk of misinterpretation in routine clinical practice. We describe a new trend interchangeability method designed to objectively define the interchangeability of each change of a variable. Using the repeatability of the reference method, we classified each change as either uninterpretable or interpretable and then as either noninterchangeable, in the gray zone or interchangeable. An interchangeability rate can then be calculated by the number of interchangeable changes divided by the total number of interpretable changes. In this observational study, we used this objective method to assess cardiac output changes with 5 arterial pulse contour techniques (Wesseling's method, LiDCO, PiCCO, Hemac method, and Modelflow) in comparison with bolus thermodilution technique as reference method in 24 cardiac surgery patients. A total of 172 cardiac output variations were available from the 199 data points: 88 (51%) were uninterpretable, according to the first step of the method. The second step of the method, based on the 84 (49%) interpretable variations, showed that only 18 (21%) to 30 (36%) variations were interchangeable regardless of the technique used. None of pulse contour cardiac output technique could be interchangeable with bolus thermodilution to assess changes in cardiac output using the trend interchangeability method in cardiac surgery patients. Future studies may consider using this method to assess interchangeability of changes between different methods

  12. The uncalibrated pulse contour cardiac output during off-pump coronary bypass surgery: performance in patients with a low cardiac output status and a reduced left ventricular function

    PubMed Central

    Jo, Youn Yi; Song, Jong Wook; Yoo, Young Chul; Park, Ji Young; Kwak, Young Lan

    2011-01-01

    Background We compared the continuous cardiac index measured by the FloTrac/Vigileo™ system (FCI) to that measured by a pulmonary artery catheter (CCI) with emphasis on the accuracy of the FCI in patients with a decreased left ventricular ejection fraction (LVEF) and a low cardiac output status during off-pump coronary bypass surgery (OPCAB). We also assessed the influence of several factors affecting the pulse contour, such as the mean arterial pressure (MAP), the systemic vascular resistance index (SVRI) and the use of norepinephrine. Methods Fifty patients who were undergoing OPCAB (30 patients with a LVEF ≥ 40%, 20 patients with a LVEF < 40%) were enrolled. The FCI and CCI were measured and we performed a Bland-Altman analysis. Subgroup analyses were done according to the LVEF (< 40%), the CCI (≤ 2.4 L/min/m), the MAP (60-80 mmHg), the SVRI (1,600-2,600 dyne/s/cm5/m2) and the use of norepinephrine. Results The FCI was reliable at all the time points of measurement with an overall bias and limit of agreement of -0.07 and 0.67 L/min/m2, respectively, resulting in a percentage error of 26.9%. The percentage errors in the patients with a decreased LVEF and in a low cardiac output status were 28.2% and 22.3%, respectively. However, the percentage error in the 91 data pairs outside the normal range of the SVRI was 40.2%. Conclusions The cardiac output measured by the FloTrac/Vigileo™ system was reliable even in patients with a decreased LVEF and in a low cardiac output status during OPCAB. Acceptable agreement was also noted during the period of heart displacement and grafting of the obtuse marginalis branch. PMID:21602972

  13. A new closed-system using partially frozen injectate for thermodilution cardiac output determinations.

    PubMed

    Maruta, H; Usuda, Y; Okutsu, Y; Numata, K

    1989-03-01

    The FI (partially frozen injectate) system, a new closed-system devised by the authors for thermodilution cardiac output determinations, has two major features: 1) it needs no ice-filled receptacle to keep injectate cold because it uses partially frozen injectate, and 2) it can go without monitoring the injectate temperatures during the whole process of cardiac output determinations. The author evaluated the accuracy and reproducibility of cardiac output determinations with the FI system in 10 critically ill patients, as compared with another closed-system (which is commercially available) and the standard open method. The injectate temperatures in the FI system were also measured in vitro. The mean injectate temperature in the FI system was 0.71 +/- 0.26 degrees C and 80% of the injectate temperatures were lower than 1.0 degrees C. Even when no monitoring of injectate temperatures was made, the predicated error in the calculated cardiac output resulted as low as 2% with the FI system. The mean cardiac output values were not statistically different between the FI system and the other two systems. PMID:15236053

  14. Influence of different atrioventricular and interventricular delays on cardiac output during cardiac resynchronization therapy.

    PubMed

    Riedlbauchová, Lucie; Kautzner, Josef; Frídl, Petr

    2005-01-01

    Restoration of the atrioventricular (AVD) and interventricular (VVD) delays increases the hemodynamic benefit conferred by biventricular (BiV) stimulation. This study compared the effects of different AVD and VVD on cardiac output (CO) during three stimulation modes: BiV-LV = left ventricle (LV) preceding right ventricle (RV) by 4 ms; BiV-RV = RV preceding LV by 4 ms; LVP = single-site LV pacing. We studied 19 patients with chronic heart failure due to ischemic or idiopathic dilated cardiomyopathy, QRS >/= 150 ms, mean LV end-diastolic diameter = 78 +/- 7 mm, and mean LV ejection fraction = 21 +/- 3%. CO was estimated by Doppler echocardiographic velocity time integral formula with sample volume placed in the LV outflow tract. Sets of sensed-AVDs (S-AVD) 90-160 ms, paced-AVDs (P-AVD) 120-160 ms, and VVDs 4-20 ms were used. BiV-RV resulted in lower CO than BiV-LV. S-AVD 120 ms and P-AVD 140 ms caused the most significant increase in CO for all three pacing modes. LVP produced a similar increase in CO as BiV stimulation; however, AV sequential pacing was associated with a nonsignificantly higher CO during LVP than with BiV stimulation. CO during BiV stimulation was the highest when LV preceded RV, and VVD ranged between 4 and 12 ms. The most negative effect on CO was observed when RV preceded LV by 4 ms. Hemodynamic improvement during BiV stimulation was dependent both on optimized AVD and VVD. LV preceding RV by 4-12 ms was the most optimal. Advancement of the RV was not beneficial in the majority of patients.

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

    PubMed

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

    2013-05-01

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

  16. Impedance cardiography for estimating cardiac output during submaximal and maximal work.

    PubMed

    Kobayashi, Y; Andoh, Y; Fujinami, T; Nakayama, K; Takada, K; Takeuchi, T; Okamoto, M

    1978-09-01

    Impedance cardiography was used to estimate cardiac output in 10 men during rest and within 5 s after exercise on a bicycle ergometer, including work up to and including maximal aerobic capacity. An indwelling venous catheter permitted simultaneous sampling of venous blood for observing changes in hematocrit associated with each exercise level. Cardiac output, calculated from a standard equation which assumes a constant value of 150 omega.cm for the electrical resistivity of blood, was compared with corresponding calculations in which blood resistivity was individually determined as a function of hematocrit. It is concluded that many of the discrepancies in the literature related to values for cardiac output obtained during exercise by the impedance method may be inherent in calculations that do not consider the changing electrical resistivity of the blood with a changing hematocrit.

  17. 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.

  18. Peripheral vasodilatation determines cardiac output in exercising humans: insight from atrial pacing.

    PubMed

    Bada, A A; Svendsen, J H; Secher, N H; Saltin, B; Mortensen, S P

    2012-04-15

    In dogs, manipulation of heart rate has no effect on the exercise-induced increase in cardiac output. Whether these findings apply to humans remain uncertain, because of the large differences in cardiovascular anatomy and regulation. To investigate the role of heart rate and peripheral vasodilatation in the regulation of cardiac output during steady-state exercise, we measured central and peripheral haemodynamics in 10 healthy male subjects, with and without atrial pacing (100–150 beats min(−1)) during: (i) resting conditions, (ii) one-legged knee extensor exercise (24 W) and (iii) femoral arterial ATP infusion at rest. Exercise and ATP infusion increased cardiac output, leg blood flow and vascular conductance (P < 0.05), whereas cerebral perfusion remained unchanged. During atrial pacing increasing heart rate by up to 54 beats min(−1), cardiac output did not change in any of the three conditions, because of a parallel decrease in stroke volume (P < 0.01). Atrial pacing increased mean arterial pressure (MAP) at rest and during ATP infusion (P < 0.05), whereas MAP remained unchanged during exercise. Atrial pacing lowered central venous pressure (P < 0.05) and pulmonary capillary wedge pressure (P < 0.05) in all conditions, whereas it did not affect pulmonary mean arterial pressure. Atrial pacing lowered the left ventricular contractility index (dP/dt) (P < 0.05) in all conditions and plasma noradrenaline levels at rest (P < 0.05), but not during exercise and ATP infusion. These results demonstrate that the elevated cardiac output during steady-state exercise is regulated by the increase in skeletal muscle blood flow and venous return to the heart, whereas the increase in heart rate appears to be secondary to the regulation of cardiac output. PMID:22351638

  19. Peripheral vasodilatation determines cardiac output in exercising humans: insight from atrial pacing

    PubMed Central

    Bada, A A; Svendsen, J H; Secher, N H; Saltin, B; Mortensen, S P

    2012-01-01

    In dogs, manipulation of heart rate has no effect on the exercise-induced increase in cardiac output. Whether these findings apply to humans remain uncertain, because of the large differences in cardiovascular anatomy and regulation. To investigate the role of heart rate and peripheral vasodilatation in the regulation of cardiac output during steady-state exercise, we measured central and peripheral haemodynamics in 10 healthy male subjects, with and without atrial pacing (100–150 beats min−1) during: (i) resting conditions, (ii) one-legged knee extensor exercise (24 W) and (iii) femoral arterial ATP infusion at rest. Exercise and ATP infusion increased cardiac output, leg blood flow and vascular conductance (P < 0.05), whereas cerebral perfusion remained unchanged. During atrial pacing increasing heart rate by up to 54 beats min−1, cardiac output did not change in any of the three conditions, because of a parallel decrease in stroke volume (P < 0.01). Atrial pacing increased mean arterial pressure (MAP) at rest and during ATP infusion (P < 0.05), whereas MAP remained unchanged during exercise. Atrial pacing lowered central venous pressure (P < 0.05) and pulmonary capillary wedge pressure (P < 0.05) in all conditions, whereas it did not affect pulmonary mean arterial pressure. Atrial pacing lowered the left ventricular contractility index (dP/dt) (P < 0.05) in all conditions and plasma noradrenaline levels at rest (P < 0.05), but not during exercise and ATP infusion. These results demonstrate that the elevated cardiac output during steady-state exercise is regulated by the increase in skeletal muscle blood flow and venous return to the heart, whereas the increase in heart rate appears to be secondary to the regulation of cardiac output. PMID:22351638

  20. 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

  1. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  3. 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.

  4. Comparison of an advanced minimally invasive cardiac output monitoring with a continuous invasive cardiac output monitoring during lung transplantation.

    PubMed

    Tomasi, Roland; Prueckner, Stephan; Czerner, Stephan; Schramm, Renè; Preissler, Gerhard; Zwißler, Bernhard; von Dossow-Hanfstingl, Vera

    2016-08-01

    The aim of this study was to compare a continuous non-calibrated left heart cardiac index (CI) measurement by arterial waveform analysis (FloTrac(®)/Vigileo(®)) with a continuous calibrated right heart CI measurement by pulmonary artery thermodilution (CCOmbo-PAC(®)/Vigilance II(®)) for hemodynamic monitoring during lung transplantation. CI was measured simultaneously by both techniques in 13 consecutive lung transplants (n = 4 single-lung transplants, n = 9 sequential double-lung transplants) at distinct time points perioperatively. Linear regression analysis and Bland-Altman analysis with percentage error calculation were used for statistical comparison of CI measurements by both techniques. In this study the FloTrac(®) system underestimated the CI in comparison with the continuous pulmonary arterial thermodilution (p < 0.000). For all measurement pairs we calculated a bias of -0.55 l/min/m(2) with limits of agreement between -2.31 and 1.21 l/min/m(2) and a percentage error of 55 %. The overall correlations before clamping a branch oft the pulmonary artery (percentage error 41 %) and during the clamping periods of a branch oft the pulmonary artery (percentage error 66 %) failed to reached the required percentage error of less than 30 %. We found good agreement of both CI measurements techniques only during the measurement point "15 min after starting the second one-lung ventilation period" (percentage error 30 %). No agreement was found during all other measurement points. This pilot study shows for the first time that the CI of the FloTrac(®) system is not comparable with the continuous pulmonary-artery thermodilution during lung transplantation including the time periods without clamping a branch of the pulmonary artery. Arterial waveform and continuous pulmonary artery thermodilution are, therefore, not interchangeable during these complex operations.

  5. Non-invasive cardiac output trending during exercise recovery on a bathroom-scale-based ballistocardiograph.

    PubMed

    Inan, O T; Etemadi, M; Paloma, A; Giovangrandi, L; Kovacs, G T A

    2009-03-01

    Cardiac ejection of blood into the aorta generates a reaction force on the body that can be measured externally via the ballistocardiogram (BCG). In this study, a commercial bathroom scale was modified to measure the BCGs of nine healthy subjects recovering from treadmill exercise. During the recovery, Doppler echocardiogram signals were obtained simultaneously from the left ventricular outflow tract of the heart. The percentage changes in root-mean-square (RMS) power of the BCG were strongly correlated with the percentage changes in cardiac output measured by Doppler echocardiography (R(2) = 0.85, n = 275 data points). The correlation coefficients for individually analyzed data ranged from 0.79 to 0.96. Using Bland-Altman methods for assessing agreement, the mean bias was found to be -0.5% (+/-24%) in estimating the percentage changes in cardiac output. In contrast to other non-invasive methods for trending cardiac output, the unobtrusive procedure presented here uses inexpensive equipment and could be performed without the aid of a medical professional.

  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.

  7. 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

  8. 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.

  9. Continuous noninvasive cardiac output determination using the CNAP system: evaluation of a cardiac output algorithm for the analysis of volume clamp method-derived pulse contour.

    PubMed

    Wagner, Julia Y; Grond, Julian; Fortin, Jürgen; Negulescu, Ileana; Schöfthaler, Miriam; Saugel, Bernd

    2016-08-01

    The CNAP system (CNSystems Medizintechnik AG, Graz, Austria) provides noninvasive continuous arterial pressure measurements by using the volume clamp method. Recently, an algorithm for the determination of cardiac output by pulse contour analysis of the arterial waveform recorded with the CNAP system became available. We evaluated the agreement of the continuous noninvasive cardiac output (CNCO) measurements by CNAP in comparison with cardiac output measurements invasively obtained using transpulmonary thermodilution (TDCO). In this proof-of-concept analysis we studied 38 intensive care unit patients from a previously set up database containing CNAP-derived arterial pressure data and TDCO values obtained with the PiCCO system (Pulsion Medical Systems SE, Feldkirchen, Germany). We applied the new CNCO algorithm retrospectively to the arterial pressure waveforms recorded with CNAP and compared CNCO with the corresponding TDCO values (criterion standard). Analyses were performed separately for (1) CNCO calibrated to the first TDCO (CNCO-cal) and (2) CNCO autocalibrated to biometric patient data (CNCO-auto). We did not perform an analysis of trending capabilities because the patients were hemodynamically stable. The median age and APACHE II score of the 22 male and 16 female patients was 63 years and 18 points, respectively. 18 % were mechanically ventilated and in 29 % vasopressors were administered. Mean ± standard deviation for CNCO-cal, CNCO-auto, and TDCO was 8.1 ± 2.7, 6.4 ± 1.9, and 7.8 ± 2.4 L/min, respectively. For CNCO-cal versus TDCO, Bland-Altman analysis demonstrated a mean difference of +0.2 L/min (standard deviation 1.0 L/min; 95 % limits of agreement -1.7 to +2.2 L/min, percentage error 25 %). For CNCO-auto versus TDCO, the mean difference was -1.4 L/min (standard deviation 1.8 L/min; 95 % limits of agreement -4.9 to +2.1 L/min, percentage error 45 %). This pilot analysis shows that CNCO determination is feasible in critically

  10. 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.

  11. Cardiac output variations in supine resting subjects during head-out cold water immersion

    NASA Astrophysics Data System (ADS)

    Vogelaere, P.; Deklunder, G.; Lecroart, J.

    1995-03-01

    Five men, aged 31.2 years (SD 2.3), under semi-nude conditions and resting in a dorsal reclining position, were exposed to thermoneutral air for 30 min, followed immediately by a cold water (15°C) immersion for 60 min. Cardiac output was measured using a dualbeam Doppler flow meter. During immersion in cold water, cardiac frequency ( f c) showed an initial bradycardia. The lowest values were reached at about 10 min after immersion, 58.3 (SD 2.5) to 48.3 (SD 7.8) beats min-1 ( P < 0.05). By the 20th min of exposure, f c had gradually risen to 70.0 beats min-1 (SD 6.6, P < 0.05). This change could be due to the inhibition of the initial vagal reflex by increased catecholamine concentration. Stroke volume ( V s) was significantly increased ( P < 0.05) during the whole cold immersion period. Cardiac output, increased from 3.57 (SD 0.50) to 6.26 (SD 1.33)1 min-1 ( P < 0.05) and its change with time was a function of both V s and f c. On the other hand, systolic flow acceleration was unchanged during the period of immersion. The changes in the respiratory variables (ventilation, oxygen uptake, carbon dioxide output and respiratory exchange ratio) during immersion showed an initial hyperventilation followed, as immersion proceeded, by a slower metabolic increase due to shivering.

  12. 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

  13. Ultrasound Dilution: An Accurate Means of Determining Cardiac Output in Children

    PubMed Central

    Crittendon, Ivory; Dreyer, William J.; Decker, Jamie A; Kim, Jeffrey J.

    2011-01-01

    Background Cardiac output (CO) is a useful measure of myocardial performance. CO monitoring is frequently performed in critically ill adults in order to guide physicians’ treatment strategies. However, standard methods of determining CO in children are not without risk and can be problematic secondary to their invasive nature and other technical problems. COstatus® system (Transonic Systems Inc, NY, USA), which is based on ultrasound dilution technology, works off in situ catheters and uses an innocuous indicator to allow for routine measurements of cardiac output and blood volumes in pediatric patients. The purpose of this study was to validate CO measured by COstatus® with those obtained by the clinical standard technique of pulmonary artery (PAC) thermodilution. Methods This was a prospective evaluation performed at a single institution. Any child with a structurally normal heart undergoing hemodynamic evaluation in the cardiac catheterization laboratory was included. A prograde right heart catheterization was performed, and CO was first determined by using the PAC thermodilution technique. Thermodilution results were then compared with CO measurements obtained using the COstatus system. The results were analyzed by standard correlation, Bland-Altman, and Crichtley and Critchley analyses. Results Twenty-eight patients were evaluated with a median age of 8 yrs and a median weight of 31 kg. The mean thermodilution cardiac index = 3.18 L/min (+/− 1.35 L/min), and the mean COstatus® cardiac index = 3.17 L/min (+/− 1.31 L/min). Standard Pearson correlation tests revealed an excellent correlation coefficient of 0.95 (p<0.0001). Bland-Altman analysis revealed good clinical agreement with a mean difference of −0.004 L/min with a precision of 0.8 L/min/ at 2 SD. A percentage error of 25.4% was noticed in this study which is less than the clinically acceptable limit. Conclusion The ultrasound dilution technique of determining CO using the COstatus® system

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. The Circadian Clock Maintains Cardiac Function by Regulating Mitochondrial Metabolism in Mice

    PubMed Central

    Kohsaka, Akira; Das, Partha; Hashimoto, Izumi; Nakao, Tomomi; Deguchi, Yoko; Gouraud, Sabine S.; Waki, Hidefumi; Muragaki, Yasuteru; Maeda, Masanobu

    2014-01-01

    Cardiac function is highly dependent on oxidative energy, which is produced by mitochondrial respiration. Defects in mitochondrial function are associated with both structural and functional abnormalities in the heart. Here, we show that heart-specific ablation of the circadian clock gene Bmal1 results in cardiac mitochondrial defects that include morphological changes and functional abnormalities, such as reduced enzymatic activities within the respiratory complex. Mice without cardiac Bmal1 function show a significant decrease in the expression of genes associated with the fatty acid oxidative pathway, the tricarboxylic acid cycle, and the mitochondrial respiratory chain in the heart and develop severe progressive heart failure with age. Importantly, similar changes in gene expression related to mitochondrial oxidative metabolism are also observed in C57BL/6J mice subjected to chronic reversal of the light-dark cycle; thus, they show disrupted circadian rhythmicity. These findings indicate that the circadian clock system plays an important role in regulating mitochondrial metabolism and thereby maintains cardiac function. PMID:25389966

  19. 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

  20. Can we obtain a noninvasive and continuous estimation of cardiac output? Comparison between three noninvasive methods.

    PubMed

    Raissuni, Zainab; Zores, Florian; Henriet, Odile; Dallest, Stephanie; Roul, Gerald

    2013-01-01

    Cardiac output (CO) is often desirable for assessing the hemodynamic condition of a patient, especially in critically ill cardiac patients. Various noninvasive methods are available for this purpose. Inert gas rebreathing (IGR) and 2D-Doppler echocardiography methods have been validated. Based on the relationship between pulse wave transit time and stroke volume, the VISMO® provides an estimated continuous cardiac output (esCCO) measurement using only an electrocardiogram, pulse oximeter wave, and cuff arterial blood pressure. Doppler echocardiography is being currently used in every day practice in this setting and IGR is a validated method, thus we wanted to assess the agreement between these 3 methods for noninvasive CO calculation and reproducibility of esCCO. Patients followed in our cardiology department received on the same day a CO analysis by esCCO, Doppler echocardiography and IGR. Thirty-four patients were included (16 women, mean age 65 ± 15 years). Bland and Altman plots showed a good agreement between IGR and 2D-Doppler echocardiography (bias = 0.31 L/minute). Though there was also an agreement between esCCO and the other 2, the bias was rather large: 1.18 L/minute with IGR and 1.51 L/min with 2D-Doppler echo. The intraclass correlation coefficient was poor whatever the methods. However, esCCO had a satisfactory reproducibility and accuracy compared rather well with the other 2. This method could be suitable for patient screening and monitoring. PMID:24309450

  1. 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

  2. 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.

  3. The effect of increased cardiac output on luteal phase gonadal steroids: a hypothesis for runners amenorrhea.

    PubMed

    Casper, R F; Wilkinson, D; Cotterell, M A

    1984-03-01

    The beta-adrenergic agonist isoproterenol was infused intravenously for 4 hours during the midluteal phase of the cycle in six normal women. A rapid increase in cardiac output occurred for the entire duration of the isoproterenol infusion and serum estrogen and progesterone levels (but not luteinizing hormone levels) decreased significantly (P less than 0.001) to a nadir of 30% and 50% of baseline levels, respectively, suggesting increased metabolic clearance of the two steroids. We hypothesize that endurance training chronically increases metabolic clearance of gonadal steroids, resulting in abnormal negative and/or positive feedback on the hypothalamic/pituitary axis leading to the menstrual irregularities commonly seen in athletes.

  4. The effect of induced hypocalcaemia on the cardiac output and blood pressure of dairy cattle.

    PubMed

    Daniel, R C; Moodie, E W

    1978-05-01

    A mean reduction of plasma calcium level to 51 per cent of normal infusion of 4.7 per cent Na2EDTA solution into four cows was associated with a mean reduction of 48 per cent in cardiac output. Hypocalcaemia sufficient to produce sternal recumbency in a further four cows resulted in a highly significant fall in the mean arterial blood pressure, which returned to normal immediately after treatment with an intravenous infusion of 350 ml of 32.5 per cent calcium borogluconate.

  5. 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.

  6. 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.

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

    PubMed Central

    2011-01-01

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

  8. Minimally invasive cardiac output monitoring: agreement of oesophageal Doppler, LiDCOrapid™ and Vigileo FloTrac™ monitors in non-cardiac surgery.

    PubMed

    Phan, T D; Kluger, R; Wan, C

    2016-05-01

    There is lack of data about the agreement of minimally invasive cardiac output monitors, which make it impossible to determine if they are interchangeable or differ objectively in tracking physiological trends. We studied three commonly used devices: the oesophageal Doppler and two arterial pressure-based devices, the Vigileo FloTrac™ and LiDCOrapid™. The aim of this study was to compare the agreement of these three monitors in adult patients undergoing elective non-cardiac surgery. Measurements were taken at baseline and after predefined clinical interventions of fluid, metaraminol or ephedrine bolus. From 24 patients, 131 events, averaging 5.2 events per patient, were analysed. The cardiac index of LiDCOrapid versus FloTrac had a mean bias of -6.0% (limits of agreement from -51% to 39%) and concordance of over 80% to the three clinical interventions. The cardiac index of Doppler versus LiDCOrapid and Doppler versus FloTrac, had an increasing negative bias at higher mean cardiac outputs and there was significantly poorer concordance to all interventions. Of the preload-responsive parameters, Doppler stroke volume index, Doppler systolic flow time and FloTrac stroke volume variation were fair at predicting fluid responsiveness while other parameters were poor. While there is reasonable agreement between the two arterial pressure-derived cardiac output devices (LiDCOrapid and Vigileo FloTrac), these two devices differ significantly to the oesophageal Doppler technology in response to common clinical intraoperative interventions, representing a limitation to how interchangeable these technologies are in measuring cardiac output. PMID:27246939

  9. In vitro determination of accuracy of cardiac output measurements by thermal dilution.

    PubMed

    Bilfinger, T V; Lin, C Y; Anagnostopoulos, C E

    1982-11-01

    The accuracy of cardiac output (C.O.) measurements by the thermodilution method was evaluated in an in vitro model within a flow range from 1 to 5 liters/min. For C.O. determinations, a 5F Swan-Ganz balloon-tipped thermodilution catheter and a 9520 Edwards computer were used. We made 420 measurements at known flow rates. In serial determinations, we achieved an overall accuracy of 86 to 93% compared to the reference flow; for single determinations, the accuracy ranged from 75 to 85%. The indicator volume (3, 5, or 10 cc) had no influence on the results. The thermodilution determinations at each flow rate were reproducible at between 2.5 and 8.5%. There was no difference in accuracy or reproducibility when ice-cold or room temperature saline was used. Caution in the interpretation of single C.O. determinations in low-flow states, i.e., in pediatric patients, is recommended.

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

    PubMed Central

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

    2014-01-01

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

  11. 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.

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

    PubMed

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

    2010-03-01

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

  13. Rowing increases stroke volume and cardiac output to a greater extent than cycling.

    PubMed

    Horn, P; Ostadal, P; Ostadal, B

    2015-01-01

    Exercise stimulates increases in heart rate (HR), stroke volume (SV) and cardiac output (CO). These adaptive mechanisms are strongly dependent on the type of exercise. Both rowing and cycling are widely used for physical training worldwide; however, evidence regarding the differences in major hemodynamic parameters during rowing and cycling remains insufficient. Ten healthy male volunteers were randomly assigned to perform either a rowing or cycling exercise. After 20 min rest, the group who had rowed first performed the cycling exercise and vice versa. Exercise was performed at a power-to-weight ratio of 2 W/kg for 2 min. HR, SV, CO and blood pressure (BP) were measured noninvasively using pulse-wave analysis at baseline and immediately after each exercise. HR, SV and CO were significantly higher after exercise than at rest. Whereas HR was comparable between rowing and cycling, SV and CO were significantly higher after rowing than after cycling. BP was comparable among all three measurements. Rowing increased SV and CO to a greater extent than cycling, whereas HR and BP were not influenced by the type of exercise. Our data suggest that rowing leads to more extensive stimulation of cardiac contractility and/or decreases in peripheral vascular resistance compared with cycling. PMID:25317691

  14. 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

  15. [Anesthesia management of geriatric patients with arterial pressure-based cardiac output monitoring FloTrac sensor for emergency surgery].

    PubMed

    Yamamoto, Shunsuke; Goto, Koji; Yasuda, Norihisa; Kusaka, Junya; Hidaka, Seigo; Miyakawa, Hiroshi; Noguchi, Takayuki

    2009-06-01

    In cases of emergency surgery for geriatric patients, immediate anesthesia induction and careful intraoperative management is necessary without sufficient preoperative information. We report anesthesia management of a 96-year and a 90-year old patients with FloTrac sensor which is an arterial pressure-based cardiac output monitoring device and is able to manage critical patients effectively and safely during anesthesia.

  16. Accuracy of thermodilution measurement of cardiac output in low flows applicable to feline and small canine patients.

    PubMed

    Dyson, D H; McDonnell, W N; Horne, J A

    1984-10-01

    A model system of feline or small canine cardiac output was used to produce known liquid flow rates in the range of 100 to 750 mL/min for comparison against a thermodilution technique of flow measurement. Thermal indicator size was decided by the thermal time concentration curve detected by the Edwards 9520A cardiac output computer. Ten consecutive readings for each flow were made. Regression analysis and Student's t-test were used to evaluate the results. The computer was found to give good correlation with the accurate flow measured by a graduated cylinder over a period of time (r = 0.99). An error of less than 7% overestimation of flow by thermodilution was found with flows greater than 200 mL/min (p less than 0.05). A significant error of more than 20% overestimation of the actual flow occurred with flows less than 200 mL/min (p less than 0.05). The Edwards 9520A computer was compared to the older Edwards 9510A model by averaged triplicate measurements at six different cardiac outputs in an anesthetized cat. The measurements were not significantly different (p less than 0.01). Thermodilution using an Edwards computer proves to be a promising tool in the measurement of low flows applicable to feline and small canine cardiac outputs. PMID:6509371

  17. Pulse contour analysis: Is it able to reliably detect changes in cardiac output in the haemodynamically unstable patient?

    PubMed Central

    2011-01-01

    Three pulse contour systems for monitoring cardiac output - LiDCO Plus™, PiCCO Plus™ and FloTrac™ - were compared in postcardiac surgery patients. None of the three methods demonstrated good trending ability according to concordance analysis. Pulse contour systems remain unreliable in the haemodynamically unstable patient. PMID:21349140

  18. 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.

  19. Left ventricular atrioventricular plane displacement is preserved with lifelong endurance training and is the main determinant of maximal cardiac output.

    PubMed

    Steding-Ehrenborg, Katarina; Boushel, Robert C; Calbet, José A; Åkeson, Per; Mortensen, Stefan P

    2015-12-01

    Age-related decline in cardiac function can be prevented or postponed by lifelong endurance training. However, effects of normal ageing as well as of lifelong endurance exercise on longitudinal and radial contribution to stroke volume are unknown. The aim of this study was to determine resting longitudinal and radial pumping in elderly athletes, sedentary elderly and young sedentary subjects. Furthermore, we aimed to investigate determinants of maximal cardiac output in elderly. Eight elderly athletes (63 ± 4 years), seven elderly sedentary (66 ± 4 years) and ten young sedentary subjects (29 ± 4 years) underwent cardiac magnetic resonance imaging. All subjects underwent maximal exercise testing and for elderly subjects maximal cardiac output during cycling was determined using a dye dilution technique. Longitudinal and radial contribution to stroke volume did not differ between groups (longitudinal left ventricle (LV) 52-65%, P = 0.12, right ventricle (RV) 77-87%, P = 0.16, radial 7.9-8.6%, P = 1.0). Left ventricular atrioventricular plane displacement (LVAVPD) was higher in elderly athletes and young sedentary compared with elderly sedentary subjects (14 ± 3, 15 ± 2 and 11 ± 1 mm, respectively, P < 0.05). There was no difference between groups for RVAVPD (P = 0.2). LVAVPD was an independent predictor of maximal cardiac output (R(2) = 0.61, P < 0.01, β = 0.78). Longitudinal and radial contributions to stroke volume did not differ between groups. However, how longitudinal pumping was achieved differed; elderly athletes and young sedentary subjects showed similar AVPD whereas this was significantly lower in elderly sedentary subjects. Elderly sedentary subjects achieved longitudinal pumping through increased short-axis area of the ventricle. Large AVPD was a determinant of maximal cardiac output and exercise capacity.

  20. Thermal dilution measurement of cardiac output in dogs using an analog computer.

    PubMed

    Hendriks, F F; Schipperheyn, J J; Quanjer, P H

    1978-01-01

    Thermal dilution cardiac output determinations in dogs were compared to simultaneously performed Fick oxygen measurements. The purpose of this study was to validate in dog experiments a method for thermal dilution measurement which employs a double-thermistor catheter combined with an automatic computer as described by Olsson et al. Dilution and injectate temperature are entered directly into the calculation. The method does not employ logarithmic extrapolation, integration of the dilution signal being terminated when a preset cut-off level is reached. Errors due to recirculation, thermal capacitance of the right heart and heat exchange with the catheter's dead space require the use of an empirically derived correction factor, which in dogs was found to be significantly different from the factor used for human thermal dilution curves. With the appropriate cut-off level and correction factor a good agreement was found between the results of the thermal dilution and the Fick method. The regression equation for 47 experiments was found to be COtd = 0.95 COFick + 0.08; the correlation coefficient was 0.94. PMID:728031

  1. Resistance reconstructed estimation of total peripheral resistance from computationally derived cardiac output - biomed 2013.

    PubMed

    Hill, Labarron K; Sollers Iii, John J; Thayer, Julian F

    2013-01-01

    Efficient functioning of the peripheral vasculature is an essential component in healthy cardiovascular regulation. Alterations in this functioning have been linked to the etiology and pathophysiological course of cardiovascular disease (CVD), especially hypertension. Given its significant role in the maintenance of both healthy and pathological blood pressure, total peripheral resistance (TPR), an index of the vasoconstrictive and elastic properties of the peripheral vasculature, has received much attention in this regard. However, obtaining a reliable estimate of TPR remains a complex and costly endeavor, primarily due to the necessity for sophisticated instrumentation as well as associated limitations in deriving cardiac output (CO). We have previously described a simple estimation method for CO using only arterial blood pressure and heart rate (Hill et al, 2012). In the present study we extend this technique to the estimation of TPR using beat-to-beat blood pressure data from the same sample of 67 young (mean age = 20.04± 2.8), healthy men (n = 30) and women (n = 37). Estimated TPR (TPRest) was calculated from the computationally-derived estimate of CO and mean arterial pressure (MAP). Correlation between TPR obtained via the validated Model-Flow technique and TPRest was moderate (r =.73, p <. 000) and stronger in men (r =.78, p <. 000) compared to women (r =.66, p <. 001). These data further suggest that reconstructed measures of hemodynamic functioning may be validly and adequately estimated from limited data sources.

  2. Oesophageal Doppler cardiac output monitoring: a longstanding tool with evolving indications and applications.

    PubMed

    Colquhoun, Douglas A; Roche, Anthony M

    2014-12-01

    Much work has been done over the years to assess cardiac output and better grasp haemodynamic profiles of patients in critical care and during major surgery. Pulmonary artery catheterization has long been considered as the standard of care, especially in critical care environments, however this dogma has been challenged over the last 10-15 years. This has led to a greater focus on alternate, lesser invasive technologies. This review focuses on the scientific and clinical outcomes basis of oesophageal Doppler monitoring. The science underpinning Doppler shift assessment of velocity stretches back over 100 years, whereas the clinical applicability, and specifically clinical outcomes improvement can be attributed to the last 20 years. Oesophageal Doppler monitoring (ODM), and its associated protocol-guided fluid administration, has been shown to reduce complications, length of stay, and overall healthcare cost when incorporated into perioperative fluid management algorithms. However, more recent advances in enhanced recovery after surgery programs have led to similar improvements, leading the clinician to consider the role of Oesophageal Doppler Monitor to be more focused in high-risk surgery and/or the high-risk patient.

  3. Measurement of cardiac output in small laboratory animals using recordings of blood conductivity.

    PubMed

    Vogel, J

    1997-11-01

    No method exists which enables easy, frequent, and, at the same time, reliable cardiac output (CO) measurements in mice. To validate a simple indicator-dilution method suitable for frequent measurements of CO in small laboratory animals, a 5% glucose solution was injected as a bolus into femoral veins of mice and rats. The corresponding blood conductivity was measured continuously between an intra-aortic and a rectal electrode. The resulting conductivity-dilution curves were used to calculate CO in mice during hypervolemia and hypovolemia and in conscious as well as halothane-anesthetized mice and rats. In rats, conductivity-dilution curves and time courses of plasma glucose concentration were recorded simultaneously. Compared with CO in awake animals, CO in both species was slightly, but not significantly, reduced during halothane anesthesia. CO was significantly and gradually reduced in hypovolemic mice (up to 58 ml blood/kg body wt), whereas hypervolemia (23 ml saline/kg body wt) had no significant effect. Simultaneous recordings of conductivity-dilution curves and time courses of plasma glucose concentration yielded corresponding values of CO (P < 0.001). Measurement of blood conductivity appears to be a reliable, simple, and convenient method for quantification of CO in small animals. PMID:9374792

  4. 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.

  5. Cardiac-Specific Disruption of GH Receptor Alters Glucose Homeostasis While Maintaining Normal Cardiac Performance in Adult Male Mice.

    PubMed

    Jara, Adam; Liu, Xingbo; Sim, Don; Benner, Chance M; Duran-Ortiz, Silvana; Qian, Yanrong; List, Edward O; Berryman, Darlene E; Kim, Jason K; Kopchick, John J

    2016-05-01

    GH is considered necessary for the proper development and maintenance of several tissues, including the heart. Studies conducted in both GH receptor null and bovine GH transgenic mice have demonstrated specific cardiac structural and functional changes. In each of these mouse lines, however, GH-induced signaling is altered systemically, being decreased in GH receptor null mice and increased in bovine GH transgenic mice. Therefore, to clarify the direct effects GH has on cardiac tissue, we developed a tamoxifen-inducible, cardiac-specific GHR disrupted (iC-GHRKO) mouse line. Cardiac GH receptor was disrupted in 4-month-old iC-GHRKO mice to avoid developmental effects due to perinatal GHR gene disruption. Surprisingly, iC-GHRKO mice showed no difference vs controls in baseline or postdobutamine stress test echocardiography measurements, nor did iC-GHRKO mice show differences in longitudinal systolic blood pressure measurements. Interestingly, iC-GHRKO mice had decreased fat mass and improved insulin sensitivity at 6.5 months of age. By 12.5 months of age, however, iC-GHRKO mice no longer had significant decreases in fat mass and had developed glucose intolerance and insulin resistance. Furthermore, investigation via immunoblot analysis demonstrated that iC-GHRKO mice had appreciably decreased insulin stimulated Akt phosphorylation, specifically in heart and liver, but not in epididymal white adipose tissue. These changes were accompanied by a decrease in circulating IGF-1 levels in 12.5-month-old iC-GHRKO mice. These data indicate that whereas the disruption of cardiomyocyte GH-induced signaling in adult mice does not affect cardiac function, it does play a role in systemic glucose homeostasis, in part through modulation of circulating IGF-1. PMID:27035649

  6. 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

  7. Organ failures due to low cardiac output syndrome following open heart surgery.

    PubMed

    Kumon, K; Tanaka, K; Hirata, T; Naito, Y; Fujita, T

    1986-04-01

    During the period from August, 1977 to December, 1984, a total of 3003 patients who received open heart surgery were treated postoperatively at the ICU of National Cardiovascular Center. Low cardiac output syndrome (LOS) developed in 669 (22.3%) patients. Organ failures due to LOS were studied in these patients. Although the overall mortality of postoperative patients was 5.6% and improved to around 4% in the later years, death rate of patients with LOS was persistently high (22.8%) and showed no tendency to improve even in the latest years. Moreover, the clinical results of those LOS patients who developed organ failure were extremely poor; the mortality of patients with respiratory failure (RF) accounted for 36.8% and that of patients with other organ failure exceeded 50%. The incidence of impaired organs in LOS patients was 49.9% in RF, 29.9% in acute renal failure (ARF), 18.4% in hepatic failure (HF), 16.4% in disseminated intravascular coagulation (DIC), 15.5% in central nervous system failure (CNSF), and 11.1% in gastrointestinal bleeding (GIB). Pathophysiological mechanisms as well as the management of these major complications caused by LOS are also discussed. Some patients developed multiple organ failure (MOF). Plasma exchange (PE) was performed on 16 patients who developed MOF. Improvement of various organ functions was obtained and consequently three patients were successfully treated by means of PE. Removal of various substances toxic to organs, supplement of deficient substances and cessation of the vicious cycle produced by the interaction of impaired organs in patients with MOF are major roles of PE in the treatment of MOF.

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

    PubMed

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

    2010-04-15

    The purpose of this study was to compare the repeatability (2.77 multiplied by the within-subject SD)between two different rebreathing protocols on cardiac output ( ˙Q ), pulmonary diffusing capacity for carbon monoxide (DLCO) and nitric oxide (DLNO), and pulmonary capillary blood volume (Vc). This study compared two bag volume protocols [Fixed Bag Volume (FBV) = bag volume fixed at 60% of forced vital capacity; Dynamic Bag Volume (DBV) = bag volume matched to tidal volume at each stage of exercise].Ten females (age = 27±8 yrs; ˙VO2, (peak)=2.5±0.6 L/min had measurements at rest (12%), 52%, 88%, and 100% of ˙VO2, (peak) on two study days. Neither the slope nor intercept of ˙Q vs. ˙VO2 were different between either bag volume protocols. The slope of DLCO vs. ˙Q was the same but the intercept was higher for the FBV protocol. The bag volume affected the slope and the intercept between DLNO vs. ˙Q (p < 0.05).The mean repeatability was similar between both protocols for ˙Q (2.0 vs. 2.3 L/min) and DLCO (3.8 vs.5.9 mL/min/mmHg), regardless of exercise intensity. Increasing exercise intensity made the measurement error worse for Vc and DLNO (p ≤ 0.06). Measurement error was lower for Vc when using the FBV protocol (p = 0.02). Also, the pattern of bag volume used during rebreathing maneuvers affected the relation between DLNO vs. ˙Q more than it affected DLCO vs. ˙Q , or Vc vs. ˙Q. Additionally, the FBV protocol provided less measurement error for Vc compared to the DBV protocol [corrected].

  9. Validation study of PulseCO system for continuous cardiac output measurement.

    PubMed

    Berberian, George; Quinn, T Alexander; Vigilance, Deon W; Park, David Y; Cabreriza, Santos E; Curtis, Lauren J; Spotnitz, Henry M

    2005-01-01

    Ultrasonic flow probes have been used to optimize biventricular pacing immediately after cardiopulmonary bypass, improving cardiac output (CO) by 10%; however, flow probes must be removed with chest closure. The PulseCO system (LiDCO Limited, Cambridge, UK) may extend optimization into the postoperative period, but controlled validations have not been reported. Six anesthetized pigs were instrumented for right heart bypass. Flow was varied from 3 to 1 L/min and then back to 3 in 0.5 L/min increments for 60 second intervals. CO was measured by ultrasonic flow probe on the aorta and by PulseCO using a femoral arterial line. PulseCO and flow probe accurately measured CO (PulseCO R2: 0.79-0.95; flow probe R2: 0.96-0.99). At flow of 2 L/min, when the heart was paced 30 bpm over the sinus rate, PulseCO falsely indicated an increase in CO (2.13 vs. 2.30 L/min, p = 0.014). When mean arterial pressure was increased by 20% using a phenylephrine infusion, PulseCO falsely indicated an increase in CO (2.13 vs. 2.47 L/min, p = 0.014). When mean arterial pressure was decreased by 20% using a nitroprusside infusion, PulseCO falsely indicated a decrease in CO (2.13 vs. 1.79 L/min, p = 0.003). PulseCO appears to be useful for assessing acute changes in CO if its limitations are recognized. PMID:15745132

  10. 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

  11. 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.

  12. Evaluation of the noninvasive estimates of cardiac output by Doppler aortoechography according to test-theoretical principles.

    PubMed

    Erb, K; Stammer, H; De Mey, C

    1997-04-01

    The usability of noninvasive methods can be quantified by a formal assessment of empirical quality criteria based on test-theoretical principles. The ACVF Doppler aortoechography is a pulsed dual-beam ultrasound technique with online estimates of cardiac output (CO) based upon the measurement of the mean Doppler shift frequency across the ascending aorta, its estimated cross-sectional area and the cycle's heart rate. The method has a relatively high reliability, sensitivity, and pharmacosensitivity (for inodilatory changes in particular), but tends to underestimate cardiac output. Furthermore, the method lacks objectivity because it is highly observer-dependent. Precise method description and stringent standardization thus are required. Because of the method specificity of its estimates, data should not be combined with those of other methods. The inherently poor validity of its CO estimates, using this method, call for caution in the mechanistic interpretation of its observations.

  13. Cardiac output and leg and arm blood flow during incremental exercise to exhaustion on the cycle ergometer.

    PubMed

    Calbet, Jose A L; Gonzalez-Alonso, Jose; Helge, Jörn W; Søndergaard, Hans; Munch-Andersen, Thor; Boushel, Robert; Saltin, Bengt

    2007-09-01

    To determine central and peripheral hemodynamic responses to upright leg cycling exercise, nine physically active men underwent measurements of arterial blood pressure and gases, as well as femoral and subclavian vein blood flows and gases during incremental exercise to exhaustion (Wmax). Cardiac output (CO) and leg blood flow (BF) increased in parallel with exercise intensity. In contrast, arm BF remained at 0.8 l/min during submaximal exercise, increasing to 1.2 +/- 0.2 l/min at maximal exercise (P < 0.05) when arm O(2) extraction reached 73 +/- 3%. The leg received a greater percentage of the CO with exercise intensity, reaching a value close to 70% at 64% of Wmax, which was maintained until exhaustion. The percentage of CO perfusing the trunk decreased with exercise intensity to 21% at Wmax, i.e., to approximately 5.5 l/min. For a given local Vo(2), leg vascular conductance (VC) was five- to sixfold higher than arm VC, despite marked hemoglobin deoxygenation in the subclavian vein. At peak exercise, arm VC was not significantly different than at rest. Leg Vo(2) represented approximately 84% of the whole body Vo(2) at intensities ranging from 38 to 100% of Wmax. Arm Vo(2) contributed between 7 and 10% to the whole body Vo(2). From 20 to 100% of Wmax, the trunk Vo(2) (including the gluteus muscles) represented between 14 and 15% of the whole body Vo(2). In summary, vasoconstrictor signals efficiently oppose the vasodilatory metabolites in the arms, suggesting that during whole body exercise in the upright position blood flow is differentially regulated in the upper and lower extremities.

  14. Effects of red cell transfusion on cardiac output and blood flow velocities in cerebral and gastrointestinal arteries in premature infants.

    PubMed Central

    Nelle, M; Höcker, C; Zilow, E P; Linderkamp, O

    1994-01-01

    Anaemia may increase the risk of tissue hypoxia in preterm infants. The effect of transfusion on circulation was studied in 33 preterm infants with a mean (SD) gestational age of 29 (5) weeks (range 26-34), birth weight 1153 (390) g (range 520-1840), and postnatal age of 48 (21) days (range 19-100). Packed cell volume, blood viscosity (capillary viscometer), cardiac output, and cerebral blood flow velocities in the internal carotid artery, anterior cerebral artery, and coeliac trunk (Doppler ultrasound) were determined before and after transfusion of 10 ml/kg of packed red blood cells. Transfusion increased packed cell volume from a mean (SD) 0.27 (0.45) to 0.37 (0.48). Mean arterial blood pressure did not change while heart rate decreased significantly from 161 (14) l/min to 149 (12). Cardiac output decreased from 367 (93) ml/kg/min to 311 (74) due to decrease in stroke volume from 2.28 (0.57) ml/kg to 2.14 (0.46) and in heart rate. There was a significant increase in systemic red cell transport (cardiac output times packed cell volume) by 17%, systemic flow resistance (blood pressure to cardiac output ratio) by 23%, and blood viscosity by 33%. Vascular hindrance (flow resistance to blood viscosity ratio) did not change significantly, thereby suggesting that neither vasoconstriction nor vasodilation occurred with transfusion. After transfusion blood flow velocities decreased significantly in the anterior cerebral artery by 23%, in the internal carotid artery by 8%, and in the coeliac trunk by 12%. Red cell transport estimated as products of blood flow velocities times packed cell volume increased significantly by 25% in the internal carotid artery and by 21% in the coeliac trunk. These results indicate that red cell transfusion improved systemic oxygen transport as well as oxygen transport in the internal carotid artery and coeliac trunk. PMID:8092871

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

    PubMed

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

    2012-04-01

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

  16. Signal processing technique for non-invasive real-time estimation of cardiac output by inductance cardiography (thoracocardiography).

    PubMed

    Bucklar, G B; Kaplan, V; Bloch, K E

    2003-05-01

    Inductance cardiography (thoracocardiography) non-invasively monitors changes in stroke volume by recording ventricular volume curves with an inductive plethysmographic transducer encircling the chest at the level of the heart. Clinical application of this method has been hampered, as data analysis has not been feasible in real time. Therefore a novel, real-time signal processing technique for inductance cardiography has been developed. Its essential concept consists in performance of multiple tasks by several, logically linked signal processing modules that have access to common databases. Based on these principles, a software application was designed that performs acquisition, display, filtering and ECG-triggered ensemble averaging of inductance signals and separates cardiogenic waveforms from noise related to respiration and other sources. The resulting ventricular volume curves are automatically analysed. Performance of the technique for monitoring cardiac output in real time was compared with thermodilution in four patients in an intensive care unit. The bias (mean difference) among 76 paired thoracocardiographic and thermodilution derived changes in cardiac output was 0%; limits of agreement (+/- 2 SD of the bias) were +/- 25%. It is concluded that the proposed signal processing technique for inductance cardiography holds promise for non-invasive, real-time estimation of changes in cardiac output.

  17. 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.

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

    PubMed Central

    Farraj, Aimen K.

    2013-01-01

    Acute air pollutant inhalation is linked to adverse cardiac events and death, and hospitalizations for heart failure. Diesel engine exhaust (DE) is a major air pollutant suspected to exacerbate preexisting cardiac conditions, in part, through autonomic and electrophysiologic disturbance of normal cardiac function. To explore this putative mechanism, we examined cardiophysiologic responses to DE inhalation in a model of aged heart failure–prone rats without signs or symptoms of overt heart failure. We hypothesized that acute DE exposure would alter heart rhythm, cardiac electrophysiology, and ventricular performance and dimensions consistent with autonomic imbalance while increasing biochemical markers of toxicity. Spontaneously hypertensive heart failure rats (16 months) were exposed once to whole DE (4h, target PM2.5 concentration: 500 µg/m3) or filtered air. DE increased multiple heart rate variability (HRV) parameters during exposure. In the 4h after exposure, DE increased cardiac output, left ventricular volume (end diastolic and systolic), stroke volume, HRV, and atrioventricular block arrhythmias while increasing electrocardiographic measures of ventricular repolarization (i.e., ST and T amplitudes, ST area, T-peak to T-end duration). DE did not affect heart rate relative to air. Changes in HRV positively correlated with postexposure changes in bradyarrhythmia frequency, repolarization, and echocardiographic parameters. At 24h postexposure, DE-exposed rats had increased serum C-reactive protein and pulmonary eosinophils. This study demonstrates that cardiac effects of DE inhalation are likely to occur through changes in autonomic balance associated with modulation of cardiac electrophysiology and mechanical function and may offer insights into the adverse health effects of traffic-related air pollutants. PMID:23047911

  19. 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

  20. Cardiac Output Monitoring Managing Intravenous Therapy (COMMIT) to Treat Emergency Department Patients with Sepsis

    PubMed Central

    Hou, Peter C.; Filbin, Michael R.; Napoli, Anthony; Feldman, Joseph; Pang, Peter S.; Sankoff, Jeffrey; Lo, Bruce M.; Dickey-White, Howard; Birkhahn, Robert H.; Shapiro, Nathan I.

    2016-01-01

    ABSTRACT Objective: Fluid responsiveness is proposed as a physiology-based method to titrate fluid therapy based on preload dependence. The objectives of this study were to determine if a fluid responsiveness protocol would decrease progression of organ dysfunction, and a fluid responsiveness protocol would facilitate a more aggressive resuscitation. Methods: Prospective, 10-center, randomized interventional trial. Inclusion criteria: suspected sepsis and lactate 2.0 to 4.0 mmol/L. Exclusion criteria (abbreviated): systolic blood pressure more than 90 mmHg, and contraindication to aggressive fluid resuscitation. Intervention: fluid responsiveness protocol using Non-Invasive Cardiac Output Monitor (NICOM) to assess for fluid responsiveness (>10% increase in stroke volume in response to 5 mL/kg fluid bolus) with balance of a liter given in responsive patients. Control: standard clinical care. Outcomes: primary—change in Sepsis-related Organ Failure Assessment (SOFA) score at least 1 over 72 h; secondary—fluids administered. Trial was initially powered at 600 patients, but stopped early due to a change in sponsor's funding priorities. Results: Sixty-four patients were enrolled with 32 in the treatment arm. There were no significant differences between arms in age, comorbidities, baseline vital signs, or SOFA scores (P > 0.05 for all). Comparing treatment versus Standard of Care—there was no difference in proportion of increase in SOFA score of at least 1 point (30% vs. 33%) (note bene underpowered, P = 1.0) or mean preprotocol fluids 1,050 mL (95% confidence interval [CI]: 786–1,314) vs. 1,031 mL (95% CI: 741–1,325) (P = 0.93); however, treatment patients received more fluids during the protocol (2,633 mL [95% CI: 2,264–3,001] vs. 1,002 mL [95% CI: 707–1,298]) (P < 0.001). Conclusions: In this study of a “preshock” population, there was no change in progression of organ dysfunction with a fluid responsiveness protocol

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

    PubMed

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

    2006-02-01

    We tested the hypothesis that the inability to increase cardiac output during exercise would explain the decreased rate of oxygen uptake (VO2) in recent onset, ischemia-induced heart failure rats. Nine normal control rats and 6 rats with ischemic heart failure were studied. Myocardial infarction was induced by coronary ligation. VO2 was measured during a ramp protocol test on a treadmill using a metabolic mask. Cardiac output was measured with a flow probe placed around the ascending aorta. Left ventricular end-diastolic pressure was higher in ischemic heart failure rats compared with normal control rats (17 +/- 0.4 vs 8 +/- 0.8 mmHg, P = 0.0001). Resting cardiac index (CI) tended to be lower in ischemic heart failure rats (P = 0.07). Resting heart rate (HR) and stroke volume index (SVI) did not differ significantly between ischemic heart failure rats and normal control rats. Peak VO2 was lower in ischemic heart failure rats (73.72 +/- 7.37 vs 109.02 +/- 27.87 mL min(-1) kg(-1), P = 0.005). The VO2 and CI responses during exercise were significantly lower in ischemic heart failure rats than in normal control rats. The temporal response of SVI, but not of HR, was significantly lower in ischemic heart failure rats than in normal control rats. Peak CI, HR, and SVI were lower in ischemic heart failure rats. The reduction in VO2 response during incremental exercise in an ischemic model of heart failure is due to the decreased cardiac output response, largely caused by depressed stroke volume kinetics.

  2. 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.

  3. 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.

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

    PubMed Central

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

    1998-01-01

    We investigated hepatic blood flow, O2 exchange and metabolism in porcine endotoxic shock (Control, n=8; Endotoxin, n=10) with administration of hydroxyethylstarch to maintain arterial pressure (MAP)>60 mmHg. Before and 12, 18 and 24 h after starting continuous i.v. endotoxin we measured portal venous and hepatic arterial blood flow, intracapillary haemoglobin O2 saturation (Hb-O2%) of the liver surface and arterial, portal and hepatic venous lactate, pyruvate, glyercol and alanine concentrations. Glucose production rate was derived from the plasma isotope enrichment during infusion of [6,6-2H2]-glucose. Despite a sustained 50% increase in cardiac output endotoxin caused a progressive, significant fall in MAP. Liver blood flow significantly increased, but endotoxin affected neither hepatic O2 delivery and uptake nor mean intracapillary Hb-O2% and Hb-O2% frequency distributions. Endotoxin nearly doubled endogenous glucose production rate while hepatic lactate, alanine and glycerol uptake rates progressively decreased significantly. The lactate uptake rate even became negative (P<0.05 vs Control). Endotoxin caused portal and hepatic venous pH to fall significantly concomitant with significantly increased arterial, portal and hepatic venous lactate/pyruvate ratios. During endotoxic shock increased cardiac output achieved by colloid infusion maintained elevated liver blood flow and thereby macro- and microcirculatory O2 supply. Glucose production rate nearly doubled with complete dissociation of hepatic uptake of glucogenic precursors and glucose release. Despite well-preserved capillary oxygenation increased lactate/pyruvate ratios reflecting impaired cytosolic redox state suggested deranged liver energy balance, possibly due to the O2 requirements of gluconeogenesis. PMID:9756385

  5. Thioredoxin-2 Inhibits Mitochondrial ROS Generation and ASK1 Activity to Maintain Cardiac Function

    PubMed Central

    Huang, Qunhua; Zhou, Huanjiao Jenny; Zhang, Haifeng; Huang, Yan; Hinojosa-Kirschenbaum, Ford; Fan, Peidong; Yao, Lina; Belardinelli, Luiz; Tellides, George; Giordano, Frank J.; Budas, Grant R.; Min, Wang

    2015-01-01

    Background Thioredoxin 2 (Trx2) is a key mitochondrial protein which regulates cellular redox and survival by suppressing mitochondrial ROS generation and by inhibiting apoptosis stress kinase-1 (ASK1)-dependent apoptotic signaling. To date, the role of the mitochondrial Trx2 system in heart failure pathogenesis has not been investigated. Methods and Results Western blot and histological analysis revealed that Trx2 protein expression levels were reduced in hearts from patients with dilated cardiomyopathy (DCM), with a concomitant increase in increased ASK1 phosphorylation/activity. Cardiac-specific Trx2 knockout mice (Trx2-cKO). Trx2-cKO mice develop spontaneous DCM at 1 month of age with increased heart size, reduced ventricular wall thickness, and a progressive decline in left ventricular (LV) contractile function, resulting in mortality due to heart failure by ~4 months of age. The progressive decline in cardiac function observed in Trx2-cKO mice was accompanied by disruption of mitochondrial ultrastructure, mitochondrial membrane depolarization, increased mitochondrial ROS generation and reduced ATP production, correlating with increased ASK1 signaling and increased cardiomyocyte apoptosis. Chronic administration of a highly selective ASK1 inhibitor improved cardiac phenotype and reduced maladaptive LV remodeling with significant reductions in oxidative stress, apoptosis, fibrosis and cardiac failure. Cellular data from Trx2-deficient cardiomyocytes demonstrated that ASK1 inhibition reduced apoptosis and reduced mitochondrial ROS generation. Conclusions Our data support an essential role for mitochondrial Trx2 in preserving cardiac function by suppressing mitochondrial ROS production and ASK1-dependent apoptosis. Inhibition of ASK1 represents a promising therapeutic strategy for the treatment of dilated cardiomyopathy and heart failure. PMID:25628390

  6. Comparison of Maximum Vasoactive Inotropic Score and Low Cardiac Output Syndrome As Markers of Early Postoperative Outcomes After Neonatal Cardiac Surgery

    PubMed Central

    Butts, Ryan J.; Scheurer, Mark A.; Atz, Andrew M.; Zyblewski, Sinai C.; Hulsey, Thomas C.; Bradley, Scott M.; Graham, Eric M.

    2014-01-01

    Low cardiac output syndrome (LCOS) and maximum vasoactive inotropic score (VIS) have been used as surrogate markers for early postoperative outcomes in pediatric cardiac surgery. The objective of this study was to determine the associations between LCOS and maximum VIS with clinical outcomes in neonatal cardiac surgery. This was a secondary retrospective analysis of a prospective randomized trial, and the setting was a pediatric cardiac intensive care unit in a tertiary care children's hospital. Neonates (n = 76) undergoing corrective or palliative cardiac operations requiring cardiopulmonary bypass were prospectively enrolled. LCOS was defined by a standardized clinical criteria. VIS values were calculated by a standard formula during the first 36 postoperative hours, and the maximum score was recorded. Postoperative outcomes included hospital mortality, duration of mechanical ventilation, intensive care unit (ICU) and hospital lengths of stay (LOS), as well as total hospital charges. At surgery, the median age was 7 days and weight was 3.2 kg. LCOS occurred in 32 of 76 (42%) subjects. Median maximum VIS was 15 (range 5–33). LCOS was not associated with duration of mechanical ventilation, ICU LOS, hospital LOS, and hospital charges. Greater VIS was moderately associated with a longer duration of mechanical ventilation (p = 0.001, r = 0.36), longer ICU LOS (p = 0.02, r = 0.27), and greater total hospital costs (p = 0.05, r = 0.22) but not hospital LOS (p = 0.52). LCOS was not associated with early postoperative outcomes. Maximum VIS has only modest correlation with duration of mechanical ventilation, ICU LOS, and total hospital charges. PMID:22349666

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

    PubMed Central

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

    2005-01-01

    Objective: To compare a new device (Innocor) for non-invasive measurement of cardiac output (CO) by foreign gas rebreathing method with conventional techniques used in the measurements of cardiac function. Methods: Cardiac outputs measured by Innocor (CORB) were compared with CO obtained by echocardiography (COEC), Swan-Ganz thermodilution (COTD), and left ventricle radiography (COLVR) in 34 patients subjected to cardiac catheterization. Values obtained from the four methods were analyzed by linear regression and paired values were compared by the method of Bland and Altman in SPSS. Results: There was strong positive correlation (r=0.94) between Innocor cardiac output values and the corresponding values obtained by thermodilution and between COEC and COLVR values. Thermodilution appears to overestimate cardiac output when compared to the values obtained with Innocor by (0.66±0.22) L/min (P<0.0001). There was no correlation between data obtained by Innocor and the corresponding COEC and COLVR values. Conclusion: Innocor CORB is an easy, safe and well established method for non-invasive measurement of cardiac output with good prospects for clinical application in heart disease patients. PMID:16358372

  8. 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

  9. Noninvasive assessment of cardiac output from arterial pressure profiles during exercise.

    PubMed

    Antonutto, G; Girardis, M; Tuniz, D; di Prampero, P E

    1995-01-01

    , MAPin, HR, PP, MAP are the above parameters at rest and during exercise, respectively. Also in this case, the coefficients f to 1 were determined by a computerized statistical method using Z* as the experimental reference. The values of Zcor so obtained allowed us to calculate SV from arterial pulse contour analysis as SVF = As.Z-1cor. The mean percentage error between the SVF obtained and the values simultaneously determined by PDE, was 10.0 (SD 8.7)%. It is concluded that the SV of the left ventricle, and hence cardiac output, can be determined during exercise from photoplethysmograph tracings with reasonable accuracy, provided that an initial estimate of SV at rest is made by means an independent high quality reference method. PMID:8789565

  10. Noninvasive assessment of cardiac output from arterial pressure profiles during exercise.

    PubMed

    Antonutto, G; Girardis, M; Tuniz, D; di Prampero, P E

    1995-01-01

    , MAPin, HR, PP, MAP are the above parameters at rest and during exercise, respectively. Also in this case, the coefficients f to 1 were determined by a computerized statistical method using Z* as the experimental reference. The values of Zcor so obtained allowed us to calculate SV from arterial pulse contour analysis as SVF = As.Z-1cor. The mean percentage error between the SVF obtained and the values simultaneously determined by PDE, was 10.0 (SD 8.7)%. It is concluded that the SV of the left ventricle, and hence cardiac output, can be determined during exercise from photoplethysmograph tracings with reasonable accuracy, provided that an initial estimate of SV at rest is made by means an independent high quality reference method.

  11. 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.

  12. 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

  13. 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

  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.

  15. Clinical review: Guyton - the role of mean circulatory filling pressure and right atrial pressure in controlling cardiac output

    PubMed Central

    2010-01-01

    Arthur Guyton's concepts of the determinative role of right heart filling in cardiac output continue to be controversial. This paper reviews his seminal experiments in detail and clarifies the often confusing concepts underpinning his model. One primary criticism of Guyton's model is that the parameters describing venous return had not been measured in a functioning cardiovascular system in humans. Thus, concerns have been expressed in regard to the ability of Guyton's simplistic model, with few parameters, to model the complex human circulation. Further concerns have been raised in regard to the artificial experimental preparations that Guyton used. Recently reported measurements in humans support Guyton's theoretical and animal work. PMID:21144008

  16. Clinical review: Guyton--the role of mean circulatory filling pressure and right atrial pressure in controlling cardiac output.

    PubMed

    Henderson, William R; Griesdale, Donald E G; Walley, Keith R; Sheel, A William

    2010-01-01

    Arthur Guyton's concepts of the determinative role of right heart filling in cardiac output continue to be controversial. This paper reviews his seminal experiments in detail and clarifies the often confusing concepts underpinning his model. One primary criticism of Guyton's model is that the parameters describing venous return had not been measured in a functioning cardiovascular system in humans. Thus, concerns have been expressed in regard to the ability of Guyton's simplistic model, with few parameters, to model the complex human circulation. Further concerns have been raised in regard to the artificial experimental preparations that Guyton used. Recently reported measurements in humans support Guyton's theoretical and animal work.

  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

  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.

  19. Influence of heart motion on cardiac output estimation by means of electrical impedance tomography: a case study.

    PubMed

    Proença, Martin; Braun, Fabian; Rapin, Michael; Solà, Josep; Adler, Andy; Grychtol, Bartłomiej; Bohm, Stephan H; Lemay, Mathieu; Thiran, Jean-Philippe

    2015-06-01

    Electrical impedance tomography (EIT) is a non-invasive imaging technique that can measure cardiac-related intra-thoracic impedance changes. EIT-based cardiac output estimation relies on the assumption that the amplitude of the impedance change in the ventricular region is representative of stroke volume (SV). However, other factors such as heart motion can significantly affect this ventricular impedance change. In the present case study, a magnetic resonance imaging-based dynamic bio-impedance model fitting the morphology of a single male subject was built. Simulations were performed to evaluate the contribution of heart motion and its influence on EIT-based SV estimation. Myocardial deformation was found to be the main contributor to the ventricular impedance change (56%). However, motion-induced impedance changes showed a strong correlation (r = 0.978) with left ventricular volume. We explained this by the quasi-incompressibility of blood and myocardium. As a result, EIT achieved excellent accuracy in estimating a wide range of simulated SV values (error distribution of 0.57 ± 2.19 ml (1.02 ± 2.62%) and correlation of r = 0.996 after a two-point calibration was applied to convert impedance values to millilitres). As the model was based on one single subject, the strong correlation found between motion-induced changes and ventricular volume remains to be verified in larger datasets.

  20. Measurement of cardiac output in children by pressure-recording analytical method.

    PubMed

    Urbano, Javier; López, Jorge; González, Rafael; Solana, María José; Fernández, Sarah N; Bellón, José M; López-Herce, Jesús

    2015-02-01

    We evaluated two pressure-recording analytical method (PRAM) software versions (v.1 and v.2) to measure cardiac index (CI) in hemodynamically stable critically ill children and investigate factors that influence PRAM values. The working hypothesis was that PRAM CI measurements would stay within normal limits in hemodynamically stable patients. Ninety-five CI PRAM measurements were analyzed in 47 patients aged 1-168 months. Mean CI was 4.1 ± 1.4 L/min/m(2) (range 2.0-7.0). CI was outside limits defined as normal (3-5 L/min/m(2)) in 53.7% of measurements (47.8% with software v.1 and 69.2% with software v.2, p = 0.062). Moreover, 14.7% of measurements were below 2.5 L/min/m(2), and 13.6% were above 6 L/min/m(2). CI was significantly lower in patients with a clearly visible dicrotic notch than in those without (3.7 vs. 4.6 L/min/m(2), p = 0.004) and in children with a radial arterial catheter (3.5 L/min/m(2)) than in those with a brachial (4.4 L/min/m(2), p = 0.021) or femoral catheter (4.7 L/min/m(2), p = 0.005). By contrast, CI was significantly higher in children under 12 months (4.2 vs. 3.6 L/min/m(2), p = 0.034) and weighing under 10 kg (4.2 vs. 3.6 L/min/m(2), p = 0.026). No significant differences were observed between cardiac surgery patients and the rest of children. A high percentage of CI measurements registered by PRAM were outside normal limits in hemodynamically stable, critically ill children. CI measured by PRAM may be influenced by the age, weight, location of catheter, and presence of a dicrotic notch.

  1. 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.

  2. Cardiac output by Doppler echocardiography in the premature baboon: comparison with radiolabeled microspheres.

    PubMed

    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). We 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.

  3. 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.

  4. 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.

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

    PubMed Central

    2011-01-01

    Introduction Uncalibrated arterial pulse power analysis has been recently introduced for continuous monitoring of cardiac index (CI). The aim of the present study was to compare the accuracy of arterial pulse power analysis with intermittent transpulmonary thermodilution (TPTD) before and after cardiopulmonary bypass (CPB). Methods Forty-two patients scheduled for elective coronary surgery were studied after induction of anaesthesia, before and after CPB respectively. Each patient was monitored with the pulse contour cardiac output (PiCCO) system, a central venous line and the recently introduced LiDCO monitoring system. Haemodynamic variables included measurement of CI derived by transpulmonary thermodilution (CITPTD) or CI derived by pulse power analysis (CIPP), before and after calibration (CIPPnon-cal., CIPPcal.). Percentage changes of CI (ΔCITPTD, ΔCIPPnon-cal./PPcal.) were calculated to analyse directional changes. Results Before CPB there was no significant correlation between CIPPnon-cal. and CITPTD (r2 = 0.04, P = 0.08) with a percentage error (PE) of 86%. Higher mean arterial pressure (MAP) values were significantly correlated with higher CIPPnon-cal. (r2 = 0.26, P < 0.0001). After CPB, CIPPcal. revealed a significant correlation compared with CITPTD (r2 = 0.77, P < 0.0001) with PE of 28%. Changes in CIPPcal. (ΔCIPPcal.) showed a correlation with changes in CITPTD (ΔCITPTD) only after CPB (r2 = 0.52, P = 0.005). Conclusions Uncalibrated pulse power analysis was significantly influenced by MAP and was not able to reliably measure CI compared with TPTD. Calibration improved accuracy, but pulse power analysis was still not consistently interchangeable with TPTD. Only calibrated pulse power analysis was able to reliably track haemodynamic changes and trends. PMID:21356060

  6. Effects of water immersion on cardiac output of lean and fat male subjects at rest and during exercise.

    PubMed

    Haffor, A S; Mohler, J G; Harrison, A C

    1991-02-01

    To investigate the combined effect of water immersion (WI) and lean body mass on cardiac output (Q), 12 healthy young men, 6 lean (fat less than 9%) and 6 fat (fat greater than 18%), were studied at rest and during steady state exercise approximating 30-40% Vo2 max under three experimental conditions. There were on land at 24 degrees C (LND), and immersed in water at 33-34 degrees C to hip level (HIP), and to the xiphoid (XIP). Metabolic measures were determined during 30-s periods from the average breath measurements. Mixed venous PCO2 (PVCO2) was estimated using rebreathing equilibration technique. Cardiac output was calculated by the indirect Fick's principle. In the lean individuals the average Q rose from a resting value of 5.43 +/- 0.43 (LND) to an exercise value of 7.25 +/- 0.40 L/min (XIP), and from resting value of 5.62 +/- 0.40 to an exercise 6.47 +/- 0.5 L/min in the fat individuals. During exercise, the associated increase in Q with increasing WI was significantly (p less than 0.05) higher compared with the land experiments. Inspection of the mean profile corresponding to this increase indicated that an increase in the level of immersion results in a significant (p less than 0.05) increase in the average Q for the lean group. For the fat group, the average Q was significantly (p less than 0.05) larger only at XIP level. At rest, heart rate dropped from 67 +/- 3.36 (LND) to 60 +/- 4.13 (XIP), and from 79 +/- 3.73 to 73 +/- 4.10 BPM for the lean and fat group, respectively. MANOVA analysis showed a significant (p less than 0.05) interaction between WI and group membership, indicating that the effect of WI is significantly different between the two groups. These data indicate that the change in central blood volume with WI depends, in part, on the lean mass of the body.

  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. A computer module for the continuous monitoring of cardiac output in the operating theatre and the ICU.

    PubMed

    Wesseling, K H; Purschke, R; Smith, N T; Wüst, H J; de Wit, B; Weber, H A

    1976-01-01

    A new pulse contour method to determine stroke volume and cardiac output continuously in patients on a beat-to-beat basis from the aortic pressure wave has been implemented in the form of a simple, inexpensive, fully automatic computing module for a commercially available patients monitoring system (Philips Medical Systems). Its reliability has been tested and shown in a computer analog, in experimental studies in 10 dogs (not reported here), in 22 hemodynamic studies on 20 young healthy volunteers and during 41 days in 20 postsurgical patients in the ICU, the most important result being that erros figures (15 and 19% respectively in the two human studies) are of the same order as when two standard methods, Fick and dye dilution are compared. The clinical studies have further indicated the easy applicability of the module 1 degree in the monitoring of critically ill patients in ICU's, 2 degrees as a monitor of the systemic circulation during anesthesia, and 3 degrees as a tool for studying the hemodynamic effects of pharmacological agents. The instrument consitutes no burden to the patients and has, several times during the course of the evaluation, provided an early warning of a deteriorating hemodynamic status of the patient to the physician.

  9. 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.

  10. Atrioventricular delays, cardiac output and diastolic function in patients with implanted dual chamber pacing and sensing pacemakers.

    PubMed

    Akbarzadeh, F; Toufan, Mehrnoush

    2008-10-15

    The Cardiac Output (CO), Filling Time (FT) and Myocardial Performance Index (MPI) derived optimal atrioventricular delay (AVD), were compared and systolic and diastolic performance at every optimal AVD were analyzed. Thirty-two patients with implanted DDD pacemaker were investigated from implantation time to 6 months following PM implantation, in Cardiovascular Research Center of Tabriz University of Medical Sciences. The evaluation was performed during AV sequential pacing with different programmed AVDS ranged from 100 to 200 msec by steps of 20-30 msec. At every AVD, the following parameters were measured: FT, mitral VTI, ET, aortic VTI, ICT and IRT. CO and FT derived optimal AVDs were significantly different (146 +/- 37 and 126 +/- 35 msec, respectively), but their difference with MPI derived optimal AVDs was not significant (130 +/- 28 msec). ICT/ET was similar at CO, FT and MPI derived optimal AVD (0.24 +/- 0.10, 0.22 +/- 0.05 and 0.20 +/- 0.07, respectively). IRT/ET ratio was similar at CO, FT and MPI derived optimal AVDs (0.46 +/- 0.14, 0.45 +/- 0.10 and 0.42 +/- 0.10, respectively). Different methods indicate different optimal AVDs. However analysis of systolic and diastolic performance shows that different AVDs result in similar systolic or diastolic performance. At MPI optimized AVD, a high CO combined with the most advantageous conditions of both isovolumic contraction and relaxation phases is achieved.

  11. Continuous cardiac output measurement by un-calibrated pulse wave analysis and pulmonary artery catheter in patients with septic shock.

    PubMed

    Ganter, Michael T; Alhashemi, Jamal A; Al-Shabasy, Adel M; Schmid, Ursina M; Schott, Peter; Shalabi, Sanaa A; Badri, Ahmed M; Hartnack, Sonja; Hofer, Christoph K

    2016-02-01

    Septic shock is a serious medical condition. With increased concerns about invasive techniques, a number of non-invasive and semi-invasive devices measuring cardiac output (CO) have become commercially available. The aim of the present study was to determine the accuracy, precision and trending abilities of the FloTrac and the continuous pulmonary artery catheter thermodilution technique determining CO in septic shock patients. Consecutive septic shock patients were included in two centres and CO was measured every 4 h up to 48 h by FloTrac (APCO) and by pulmonary artery catheter (PAC) using the continuous (CCO) and intermittent (ICO) technique. Forty-seven septic shock patients with 326 matched sets of APCO, CCO and ICO data were available for analysis. Bland and Altman analysis revealed a mean bias ±2 SD of 0.0 ± 2.14 L min(-1) for APCO-ICO (%error = 34.5 %) and 0.23 ± 2.55 L min(-1) for CCO-ICO (%error = 40.4 %). Trend analysis showed a concordance of 85 and 81 % for APCO and CCO, respectively. In contrast to CCO, APCO was influenced by systemic vascular resistance and by mean arterial pressure. In septic shock patients, APCO measurements assessed by FloTrac but also the established CCO measurements using the PAC did not meet the currently accepted statistical criteria indicating acceptable clinical performance.

  12. First in vivo application and evaluation of a novel method for non-invasive estimation of cardiac output.

    PubMed

    Papaioannou, Theodore G; Soulis, Dimitrios; Vardoulis, Orestis; Protogerou, Athanase; Sfikakis, Petros P; Stergiopulos, Nikolaos; Stefanadis, Christodoulos

    2014-10-01

    Surgical or critically ill patients often require continuous assessment of cardiac output (CO) for diagnostic purposes or for guiding therapeutic interventions. A new method of non-invasive CO estimation has been recently developed, which is based on pressure wave analysis. However, its validity has been examined only in silico. Aim of this study was to evaluate in vivo the reproducibility and accuracy of the "systolic volume balance" method (SVB). Twenty two subjects underwent 2-D transthoracic echocardiography for CO measurement (reference value of CO). The application of SVB method required aortic pressure wave analysis and estimation of total arterial compliance. Aortic pulses were derived by mathematical transformation of radial pressure waves recorded by applanation tonometry. Total compliance was estimated by the "pulse pressure" method. The agreement, association, variability, bias and precision between Doppler and SVB measures of CO were evaluated by intraclass correlation coefficient (ICC), mean difference, SD of differences, percentage error (PR) and Bland-Altman analysis. SVB yielded very reproducible CO estimates (ICC=0.84, mean difference 0.27 ± 0.73 L/min, PR = 16.7%). SVB-derived CO was comparable with Doppler measurements, indicating a good agreement and accuracy (ICC = 0.74, mean difference = -0.22 ± 0.364 L/min, PR ≈ 15). The basic mathematical and physical principles of the SVB method provide highly reproducible and accurate estimates of CO compared with echocardiography. PMID:25108554

  13. Continuous measurement of cardiac output with the electrical velocimetry method in patients under spinal anesthesia for cesarean delivery.

    PubMed

    Liu, Yanhong; Pian-Smith, May C M; Leffert, Lisa R; Minehart, Rebecca D; Torri, Andrea; Coté, Charles; Kacmarek, Robert M; Jiang, Yandong

    2015-10-01

    In this study, we aimed to continuously measure cardiac output (CO) with the electrical velocimetry (EV) method and characterize the hemodynamic profile of patients undergoing spinal anesthesia for elective cesarean delivery (CD), and to discuss the potential benefit of using real time CO monitoring to guide patient management. Forty-two patients scheduled for elective CD under spinal anesthesia were enrolled in this observational study. A non-invasive CO monitor incorporating the electrical velocimetry algorithm, ICON(®) (Cardiotronic(®), La Jolla, California, USA), was used to measure CO and stroke volume (SV) continuously. Peripheral venous pressure was measured intermittently at pre-defined time points. Systemic vascular resistance was calculated retrospectively after completion of the study. Hemodynamic changes at pre-defined time points and caused by phenylephrine administration were analyzed. Hypotension (MAP reduction more than 20% from baseline values) occurred in 71.1% of patients after spinal anesthesia, while the coinstantaneous CO was increased ≥20% from baseline in the majority of patients (76.3%) at the same time. Significant increase in CO took place at 3-2 min before the administration of phenylephrine bolus. Treatment of hypotension with phenylephrine was associated with significant decrease in CO. Continuous CO monitoring with EV enables clinicians to determine CO and SV changes prior to onset of hypotension and to better understand patients' hemodynamics. It is an important addition to the current monitoring. The benefit of routinely using this technique remains to be determined in term of the patient outcomes. PMID:25510959

  14. 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

  15. 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

  16. 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.

  17. Accuracy and precision of minimally-invasive cardiac output monitoring in children: a systematic review and meta-analysis.

    PubMed

    Suehiro, Koichi; Joosten, Alexandre; Murphy, Linda Suk-Ling; Desebbe, Olivier; Alexander, Brenton; Kim, Sang-Hyun; Cannesson, Maxime

    2016-10-01

    Several minimally-invasive technologies are available for cardiac output (CO) measurement in children, but the accuracy and precision of these devices have not yet been evaluated in a systematic review and meta-analysis. We conducted a comprehensive search of the medical literature in PubMed, Cochrane Library of Clinical Trials, Scopus, and Web of Science from its inception to June 2014 assessing the accuracy and precision of all minimally-invasive CO monitoring systems used in children when compared with CO monitoring reference methods. Pooled mean bias, standard deviation, and mean percentage error of included studies were calculated using a random-effects model. The inter-study heterogeneity was also assessed using an I(2) statistic. A total of 20 studies (624 patients) were included. The overall random-effects pooled bias, and mean percentage error were 0.13 ± 0.44 l min(-1) and 29.1 %, respectively. Significant inter-study heterogeneity was detected (P < 0.0001, I(2) = 98.3 %). In the sub-analysis regarding the device, electrical cardiometry showed the smallest bias (-0.03 l min(-1)) and lowest percentage error (23.6 %). Significant residual heterogeneity remained after conducting sensitivity and subgroup analyses based on the various study characteristics. By meta-regression analysis, we found no independent effects of study characteristics on weighted mean difference between reference and tested methods. Although the pooled bias was small, the mean pooled percentage error was in the gray zone of clinical applicability. In the sub-group analysis, electrical cardiometry was the device that provided the most accurate measurement. However, a high heterogeneity between studies was found, likely due to a wide range of study characteristics. PMID:26315477

  18. Acute heart failure with low cardiac output: can we develop a short-term inotropic agent that does not increase adverse events?

    PubMed

    Campia, Umberto; Nodari, Savina; Gheorghiade, Mihai

    2010-09-01

    Acute heart failure represents an increasingly common cause of hospitalization, and may require the use of inotropic drugs in patients with low cardiac output and evidence of organ hypoperfusion. However, currently available therapies may have deleterious effects and increase mortality. An ideal inotropic drug should restore effective tissue perfusion by enhancing myocardial contractility without causing adverse effects. Such a drug is not available yet. New agents with different biological targets are under clinical development. In particular, istaroxime seems to dissociate the inotropic effect exerted by digitalis (inhibition of the membrane sodium/potassium adenosine triphosphatase) from the arrhythmic effect and to ameliorate diastolic dysfunction (via sarcoendoplasmic reticulum calcium adenosine triphosphatase activation). Additionally, the myosin activator omecamtiv mecarbil appears to have promising characteristics, while genetic therapy has been explored in animal studies only. Further investigations are needed to confirm and expand the effectiveness and safety of these agents in patients with acute heart failure and low cardiac output.

  19. Importance of re-calibration time on pulse contour analysis agreement with thermodilution measurements of cardiac output: a retrospective analysis of intensive care unit patients.

    PubMed

    Scully, Christopher G; Gomatam, Shanti; Forrest, Shawn; Strauss, David G

    2016-10-01

    We assessed the effect of re-calibration time on cardiac output estimation and trending performance in a retrospective analysis of an intensive care unit patient population using error grid analyses. Paired thermodilution and arterial blood pressure waveform measurements (N = 2141) from 222 patient records were extracted from the Multiparameter Intelligent Monitoring in Intensive Care II database. Pulse contour analysis was performed by implementing a previously reported algorithm at calibration times of 1, 2, 8 and 24 h. Cardiac output estimation agreement was assessed using Bland-Altman and error grid analyses. Trending was assessed by concordance and a 4-Quadrant error grid analysis. Error between pulse contour and thermodilution increased with longer calibration times. Limits of agreement were -1.85 to 1.66 L/min for 1 h maximum calibration time compared to -2.70 to 2.41 L/min for 24 h. Error grid analysis resulted in 74.2 % of points bounded by 20 % error limits of thermodilution measurements for 1 h calibration time compared to 65 % for 24 h. 4-Quadrant error grid analysis showed <75 % of changes in pulse contour estimates to be within ±80 % of the change in the thermodilution measurement at any calibration time. Shorter calibration times improved the agreement of cardiac output pulse contour estimates with thermodilution. Use of minimally invasive pulse contour methods in intensive care monitoring could benefit from prospective studies evaluating calibration protocols. The applied pulse contour analysis method and thermodilution showed poor agreement to monitor changes in cardiac output.

  20. 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

  1. 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.

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

    PubMed

    Brochu, Pierre; Brodeur, Jules; Krishnan, Kannan

    2012-08-01

    Physiologically based pharmacokinetic modeling and occupational exposure assessment studies often use minute ventilation rates (VE), alveolar ventilation rates (VA) and cardiac outputs (Q) that are not reflective of the physiological variations encountered during the aggregate daytime activities of individuals from childhood to adulthood. These variations of VE, VA and Q values were determined for healthy normal-weight individuals aged 5-96 years by using two types of published individual data that were measured in the same subjects (n = 902), namely indirect calorimetry measurements and the disappearance rates of oral doses of deuterium (²H) and heavy-oxygen (¹⁸O) in urine monitored by gas-isotope-ratio mass spectrometry. Arteriovenous oxygen content differences (0.051-0.082 ml of O₂ consumed ml⁻¹ of blood) and ratios of the physiological dead space to the tidal volume (0.232-0.419) were determined for oxygen consumption rates (0.157-0.806 l min⁻¹) required by minute energy expenditures ranging from 0.76 to 3.91 kcal min⁻¹. Generally higher values for the 2.5th up to the 99th percentile for VE (0.132-0.774 l kg⁻¹ min⁻¹, 4.42-21.69 l m⁻² min⁻¹), VA (0.093-0.553 l kg⁻¹ min⁻¹, 3.09-15.53 l m⁻² min⁻¹), Q (0.065-0.330 l kg⁻¹ min⁻¹, 2.17 to 9.46 l m⁻² min⁻¹) and ventilation-perfusion ratios (1.12-2.16) were found in children and teenagers aged 5-<16.5 years compared with older individuals. The distributions of cardiopulmonary parameters developed in this study should be useful in facilitating a scientifically sound characterization of the inter-individual differences in the uptake and health risks of lipophilic air pollutants, particularly as they relate to younger children.

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

    PubMed

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

    2014-06-01

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

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

    PubMed

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

    2014-01-01

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

  5. Effects of gradual volume loading on left ventricular diastolic function in dogs: implications for the optimisation of cardiac output.

    PubMed Central

    Fragata, J.; Areias, J. C.

    1996-01-01

    BACKGROUND: Volume loading is commonly used to adjust preload and optimise cardiac output. It is difficult to monitor preload at the bedside because filling affects ventricular diastolic function and consequently end diastolic pressure, which is the variable used to monitor preload. OBJECTIVE: To assess the effects of gradual volume loading on the different components of left ventricular diastolic function---filling velocities, relaxation, and chamber compliance---to identify how excessive loading produces diastolic dysfunction. METHODS AND RESULTS: Eight mongrel dogs, anaesthetised and mechanically ventilated with both the chest and the pericardium closed, were studied during basal conditions (B), during gradual volume loading with physiological saline---5 ml/kg (VL5), 10 ml/kg (VL10), and 15 ml/kg (VL15)---and during infusion of isosorbide dinitrate (10 g/kg/min) started after the VL15 load was achieved. Dogs were monitored haemodynamically and by transthoracic Doppler echocardiography to assess peak modal velocities of the E and A waves, E/A ratios, and the deceleration time of the E wave. M mode recordings of aligned mitral and aortic valve motion were also obtained to calculate the isovolumic relaxation time. Effects of volume loading on ventricular diastolic function seemed to occur in two phases. Small and moderate volume loads (VL5 and VL10) promoted early ventricular filling, increasing E wave velocities, improving the mean (SD) E/A ratio from 1.95 (0.3) (B) to 2.0 (0.27) (VL5) and 2.6 (0.3) (VL10) (P < 0.00005), prolonging the E wave deceleration time, and only slightly increasing ventricular diastolic pressures. These changes suggest an improvement in ventricular compliance. Extreme volume loads (VL15) produced an abrupt reduction in early ventricular filling, which was transfered to late in diastole, by decreasing E wave velocity, by increasing A wave velocity, and by decreasing E/A ratio from 2.6 (0.3) (VL10) to 0.8 (0.05) (VL15) (P < 0.00005). The E

  6. 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

  7. 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.

  8. Serum uric acid is inversely proportional to estimated stroke volume and cardiac output in a large sample of pharmacologically untreated subjects: data from the Brisighella Heart Study.

    PubMed

    Cicero, Arrigo Francesco Giuseppe; Rosticci, Martina; Parini, Angelo; Baronio, Cristina; D'Addato, Sergio; Borghi, Claudio

    2014-09-01

    Serum uric acid is representative for xanthine-oxidase, the key enzyme involved in the production of uric acid, which is up-regulated in the failing heart, and may play an important role in the pathophysiologic process that leads to heart failure. In our study, we investigated the relation between stroke volume, cardiac output and serum uric acid in a large sample of overall healthy pharmacologically untreated subjects. The Brisighella Heart Study included 2,939 men and women between the ages of 14-84 without prior coronary heart disease or cerebrovascular disease who were not taking antihypertensive therapy at baseline. For this study, we selected 734 adult subjects enrolled in the last Brisighella population survey not taking antihypertensive, antidiabetic, lipid-lowering and uric acid-lowering drugs, and who were also not affected by chronic heart failure or by gout. The main predictors of cardiac functionality parameters were mean arterial pressure (MAP), HR, SUA and age (all p < 0.001), while gender, BMI, LDL-cholesterol, HDL-cholesterol, triglycerides, fasting plasma glucose, creatinine, estimated glomerular filtration rate, physical activity and smoking habit were not significantly associated (all p > 0.05). In particular, there is a strong relation between estimated cardiac output and serum uric acid (B = -0.219, p < 0.001) and between stroke volume and serum uric acid (B = -3.684, p < 0.001). These observations might have an impact on future considerations about serum uric acid as an early inexpensive marker of heart function decline in the general population. PMID:24214336

  9. Coconut Haustorium Maintains Cardiac Integrity and Alleviates Oxidative Stress in Rats Subjected to Isoproterenol-induced Myocardial Infarction

    PubMed Central

    Chikku, A. M.; Rajamohan, T.

    2012-01-01

    The present study evaluates the effect of aqueous extract of coconut haustorium on isoproterenol-induced myocardial infarction in Sprague Dawley rats. Rats were pretreated with aqueous extract of coconut haustorium (40 mg/100 g) orally for 45 days. After pretreatment, myocardial infarction was induced by injecting isoproterenol subcutaneously (20 mg/100 g body weight) twice at an interval of 24 h. Activity of marker enzymes like lactate dehydrogenase, creatinine kinase-MB, aspartate transaminase and alanine transaminase were increased in the serum and decreased in the heart of isoproterenol treated rats indicating cardiac damage. These changes were significantly reduced in haustorium pretreated rats. Moreover, an increase in the activities of antioxidant enzymes and decrease in the levels of peroxidation products were observed in the myocardium of coconut haustorium pretreated rats. Histopathology of the heart of these rats showed almost normal tissue morphology. From these results, it is clear that aqueous extract of coconut haustorium possess significant cardioprotective and antioxidant properties during isoproterenol-induced myocardial infarction in rats. PMID:23716867

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

    PubMed Central

    2014-01-01

    Introduction Delayed graft function (DGF) remains a significant and detrimental postoperative phenomenon following living-related renal allograft transplantation, with a published incidence of up to 15%. Early therapeutic vasodilatory interventions have been shown to improve DGF, and modifications to immunosuppressive regimens may subsequently lessen its impact. This pilot study assesses the potential applicability of perioperative non-invasive cardiac output monitoring (NICOM), transit-time flow monitoring (TTFM) of the transplant renal artery and pre-/perioperative thromboelastography (TEG) in the early prediction of DGF and perioperative complications. Methods Ten consecutive living-related renal allograft recipients were studied. Non-invasive cardiac output monitoring commenced immediately following induction of anaesthesia and was maintained throughout the perioperative period. Doppler-based TTFM was performed during natural haemostatic pauses in the transplant surgery: immediately following graft reperfusion and following ureteric implantation. Central venous blood sampling for TEG was performed following induction of anaesthesia and during abdominal closure. Results A single incidence of DGF was seen within the studied cohort and one intra-operative (thrombotic) complication noted. NICOM confirmed a predictable trend of increased cardiac index (CI) following allograft reperfusion (mean CI - clamped: 3.17 ± 0.29 L/min/m2, post-reperfusion: 3.50 ± 0.35 L/min/m2; P < 0.05) mediated by a significant reduction in total peripheral resistance. Reduced TTFM at the point of allograft reperfusion (227 ml/min c.f. mean; 411 ml/min (95% CI: 358 to 465)) was identified in a subject who experienced intra-operative transplant renal artery thrombosis. TEG data exhibited significant reductions in clot lysis (LY30 (%): pre-op: 1.0 (0.29 to 1.71), post reperfusion 0.33 (0.15 to 0.80); P = 0.02) and a trend towards increased clot initiation following

  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. [Why do workers apply for disability pension although their vocational ability is maintained? - a qualitative study of patients after cardiac events].

    PubMed

    Brauer, J; Mittag, O; Raspe, H

    2009-12-01

    The central question of this study is why workers in the employable age group apply for disability pension although from a medical point of view their vocational ability is maintained. The aim is to identify factors in the system and of the applicant which may serve as subjective prognostic indicators for maintaining employment and for determining influences which may be of prognostic value for a pension application. Concomitantly, it is aimed to obtain guidelines for practical rehabilitation and to generate impulses for further research in this field. Within a qualitative research project 16 problem-focused interviews with patients insured by "Deutsche Rentenversicherung Nord" and treated in a cardiac rehabilitation centre in Mecklenburg-Vorpommern were undertaken. Patients with either a positive or a negative subjective prognosis concerning employment were interviewed. In addition, the interviews were followed by a questionnaire one year later. The results show differences and similarities in the motivation of patients applying for disability pension. This can be traced back to psychosocial variables, sociodemographic characteristics, moderating factors and the effects of socialisation. Physical impairment was of secondary importance to the patients' motivation to apply for disability pension. The results of the follow-up questionnaire show that an existing job significantly improves the subjective prognosis for maintaining gainful employment. The application for disability pension offers the affected individual a possibility to ensure a basic existence in the case of illness and unemployment. The identified factors may be influenced by modifying the interventions and improving medical counselling during the rehabilitation period.

  13. Left ventricular unloading and concomitant total cardiac output increase by the use of percutaneous Impella Recover LP 2.5 assist device during high-risk coronary intervention.

    PubMed

    Valgimigli, Marco; Steendijk, Paul; Sianos, George; Onderwater, Emile; Serruys, Patrick W

    2005-06-01

    A number of techniques have been proposed for circulatory support during high-risk percutaneous coronary interventions (PCI), but no single approach has achieved wide acceptance so far. We report on a patient with severe left ventricular (LV) impairment who underwent a PCI with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system. The effects on global cardiac output were determined by thermodilution (TD) and LV pressure-volume loops obtained by conductance catheter. The activation of the pump resulted in a rapid and sustained unloading effect of the LV. At the same time, the continuous expulsion of blood into ascending aorta throughout the cardiac cycle produced by the pump resulted in an increase of systemic overall CO, measured by the TD technique, of 1.43 L/min. The procedure was uncomplicated and the patient remained uneventful at follow-up. Our single experience gives new input for future trials to assess the effect of the Impella Recover LP 2.5 assist device on outcome in this subset of patients.

  14. Extracorporeal membrane oxygenation as a support for TGA/IVS with low cardiac output syndrome and pulmonary hemorrhage.

    PubMed

    Hong, Xiaoyang; Feng, Zhichun; Zhou, Gengxu; Xu, Xuan

    2013-06-01

    A 15-day-old neonate with complete transposition of the great arteries/intact ventricular septum was admitted with life-threatening hypoxemia and heart arrest. After successful resuscitation, heart beat recovered but blood lactate began to arise and maintained above 15 mmol/L 6 hours later. Emergency arterial switch operation was done at 20 hours after resuscitation. Planned extracorporeal membrane oxygenation support was employed postoperatively. The baby experienced severe pulmonary hemorrhage and severe hypoxemia after weaning from cardiopulmonary bypass, which were treated with extracorporeal membrane oxygenation support.

  15. 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.

  16. The relation between cardiac output kinetics and skeletal muscle oxygenation during moderate exercise in moderately impaired patients with chronic heart failure.

    PubMed

    Spee, Ruud F; Niemeijer, Victor M; Schoots, Thijs; Wijn, Pieter F; Doevendans, Pieter A; Kemps, Hareld M

    2016-07-01

    Oxygen uptake (V̇o2) kinetics are prolonged in patients with chronic heart failure (CHF). This may be caused by impaired oxygen delivery or skeletal muscle derangements. We investigated whether impaired cardiac output (Q̇) kinetics limit skeletal muscle oxygen delivery relative to the metabolic demands at submaximal exercise in CHF patients by evaluating the relation between Q̇ kinetics and skeletal muscle deoxygenation. Forty-three CHF patients, NYHA II-III, performed a constant-load exercise test at 80% of the ventilatory aerobic threshold (VAT) to assess V̇o2 kinetics (τV̇o2). Q̇ kinetics (τQ̇) were assessed by a radial artery pulse contour analysis method. Skeletal muscle deoxygenation was assessed by near infrared spectroscopy at the m. vastus lateralis, using the minimal value of the tissue saturation index during onset of exercise (TSImin). Patients were categorized in slow and normal Q̇ responders relative to metabolic demands (τQ̇/V̇o2 ≥1 and τQ̇/V̇o2 <1, respectively), τQ̇ (62 ± 29 s), and τV̇o2 (60 ± 21 s) were significantly related (r = 0.66, P = 0.001). There was a significant correlation between τQ̇ and TSImin in the slow Q̇ responders [rs= -0.57, P = 0.005, n = 22 (51%)]. In conclusion, in moderately impaired CHF patients with relatively slow Q̇ kinetics, central hemodynamics may limit skeletal muscle oxygenation during moderate-intensity exercise. PMID:27283909

  17. The reproducibility of measurement of right ventricular ejection fraction and cardiac output by the thermodilution technique in patients on mechanical ventilation.

    PubMed

    Jensen, P J; Andersen, P K; Thøgersen, C

    1994-07-01

    Thermodilution determined right ventricular ejection fraction (RVEF) and cardiac output (CO) were measured in 48 critically ill patients requiring mechanical ventilation and inotropic and/or vasoactive drugs. The coefficient of variation on CO and RVEF were calculated from triple determinations. The average coefficient of variation based on 551 triple determinations was 12.6% for RVEF (range 2-51%) and 4.9% for CO (range 0-24%). If a 10% coefficient of variation was chosen as acceptable, 95% of the CO measurements were acceptable. The coefficient of variation on RVEF only fulfilled the 10% criteria in 46% of the measurements, but if the accepted level was raised to a 20% coefficient of variation, 90% of the measurements were acceptable. The measurement of RVEF and CO are used for calculation of e.g. right ventricular end diastolic volume (RVEDV). By applying the average coefficient of variation of RVEF and CO, the accumulated error on calculation of RVEDV was found to be divided by 15%- +20% at worst. Before derived parameters such as RVEDV are interpreted or compared with previously obtained values, the accumulated error should be calculated. To ensure the quality of the measurements, our recommendation is always to calculate the coefficient of variation for each triple determination of RVEF and CO. PMID:7941945

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

    PubMed

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

    1978-09-01

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

  19. The 5-hydroxytryptamine1A receptor agonist, (+)-8-hydroxy-2-(di-n-propylamino)-tetralin, increases cardiac output and renal perfusion in rats subjected to hypovolemic shock.

    PubMed

    Tiniakov, Ruslan; Osei-Owusu, Patrick; Scrogin, Karie E

    2007-02-01

    The 5-hydroxytryptamine(1A) receptor agonist, (+)-8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), raises blood pressure (BP) and venous tone in rats subjected to hemorrhagic shock. Here, BP, ascending aortic blood flow [i.e., estimate of cardiac output (CO)] and venous blood gases were measured to determine the hemodynamic effects of 8-OH-DPAT (30 nmol/kg i.v., n = 10), saline (n = 10), or an equipressor infusion of epinephrine (n = 10) in unanesthetized rats subjected to hemorrhagic shock (25 min of hypotensive hemorrhage, approximately 50 mm Hg). Renal and iliac blood flow were measured in separate groups of similarly hemorrhaged rats given the same dose of 8-OH-DPAT (n = 7) or saline (n = 6). Compared with saline treatment, 8-OH-DPAT produced a sustained rise in BP (+32 +/- 4 versus +9 +/- 2 mm Hg, 15 min after injection, P < 0.01) and CO (+27 +/- 5 versus +4 +/- 6 ml/min/kg, P < 0.01) but did not affect total peripheral resistance (TPR). Infusion of epinephrine reduced CO (-12 +/- 6 ml/min/kg, P < 0.01) and dramatically increased TPR [+0.37 +/- 0.11 versus +0.05 +/- 0.05 log (mm Hg/ml/min/kg), P < 0.01]. 8-OH-DPAT increased renal conductance (+7 +/- 1 versus +4 +/- 1 microl/min/mm Hg, P < 0.01) but did not significantly affect iliac conductance. 8-OH-DPAT attenuated further development of acidosis compared with either saline or epinephrine (-5.6 +/- 1.6 versus -13.0 +/- 2.0 versus -11.3 +/- 2.6 mmol/liter base excess 45 min after start of hemorrhage, both P < 0.01 versus 8-OH-DPAT). These data demonstrate that 8-OH-DPAT improves hemodynamics during circulatory shock, in part, through renal vasodilation and mobilizing of blood stores.

  20. Phase I dynamics of cardiac output, systemic O2 delivery, and lung O2 uptake at exercise onset in men in acute normobaric hypoxia.

    PubMed

    Lador, Frédéric; Tam, Enrico; Azabji Kenfack, Marcel; Cautero, Michela; Moia, Christian; Morel, Denis R; Capelli, Carlo; Ferretti, Guido

    2008-08-01

    We tested the hypothesis that vagal withdrawal plays a role in the rapid (phase I) cardiopulmonary response to exercise. To this aim, in five men (24.6+/-3.4 yr, 82.1+/-13.7 kg, maximal aerobic power 330+/-67 W), we determined beat-by-beat cardiac output (Q), oxygen delivery (QaO2), and breath-by-breath lung oxygen uptake (VO2) at light exercise (50 and 100 W) in normoxia and acute hypoxia (fraction of inspired O2=0.11), because the latter reduces resting vagal activity. We computed Q from stroke volume (Qst, by model flow) and heart rate (fH, electrocardiography), and QaO2 from Q and arterial O2 concentration. Double exponentials were fitted to the data. In hypoxia compared with normoxia, steady-state fH and Q were higher, and Qst and VO2 were unchanged. QaO2 was unchanged at rest and lower at exercise. During transients, amplitude of phase I (A1) for VO2 was unchanged. For fH, Q and QaO2, A1 was lower. Phase I time constant (tau1) for QaO2 and VO2 was unchanged. The same was the case for Q at 100 W and for fH at 50 W. Qst kinetics were unaffected. In conclusion, the results do not fully support the hypothesis that vagal withdrawal determines phase I, because it was not completely suppressed. Although we can attribute the decrease in A1 of fH to a diminished degree of vagal withdrawal in hypoxia, this is not so for Qst. Thus the dual origin of the phase I of Q and QaO2, neural (vagal) and mechanical (venous return increase by muscle pump action), would rather be confirmed.

  1. Evaluation of New Calibrated Pulse-Wave Analysis (VolumeViewTM/EV1000TM) for Cardiac Output Monitoring Undergoing Living Donor Liver Transplantation

    PubMed Central

    Park, MiHye; Han, Sangbin; Kim, Gaab Soo; Gwak, Mi Sook

    2016-01-01

    Background Intrapulmonary thermodilution technique using a pulmonary artery catheter is widely used for measuring cardiac output (CO) in patients undergoing liver transplantation. However, its invasiveness and associated complications have led to an interest in less invasive modalities. Thus, we aimed to evaluate whether the new calibrated pulse-wave analysis method monitoring (VolumeViewTM/EV1000TM) is interchangeable with intrapulmonary thermodilution technique. Methods Twenty-eight patients undergoing living donor liver transplantation were enrolled in this prospective observational study. COs were recorded automatically by the two devices and compared simultaneously at 10-minute intervals. The agreement of absolute CO values and the tracking ability of CO changes trends were compared. A Bland-Altman analysis with percentage errors and concordance rate for trend analysis using both a 4-quadrant plot and a polar plot were performed on the data. Results A total of 375 paired datasets from 25 patients were included in analysis. COs measured by intrapulmonary thermodilution ranged from 3.8–13.7 L/min. The mean CO difference between the two techniques was 0.57 L/min, and the 95% limits of agreement were -0.98 L/min to 2.12 L/min with a percentage error of 42.3%. The percentage errors in the dissection, anhepatic, and reperfusion phase were 30.5%, 31.7%, and 27.4%, respectively. The concordance rate between the two techniques was 78.4%. Conclusion The calibrated pulse-wave analysis and intrapulmonary thermodilution failed to show acceptable interchangeability in terms of both estimating CO and tracking CO changes during living donor liver transplantation. PMID:27736921

  2. The effect of head up tilting on bioreactance cardiac output and stroke volume readings using suprasternal transcutaneous Doppler as a control in healthy young adults.

    PubMed

    Zhang, Jie; Critchley, Lester A H; Lee, Daniel C W; Khaw, Kim S; Lee, Shara W Y

    2016-10-01

    To compare the performance of a bioreactance cardiac output (CO) monitor (NICOM) and transcutaneous Doppler (USCOM) during head up tilting (HUT). Healthy young adult subjects, age 22 ± 1 years, 7 male and 7 female, were tilted over 3-5 s from supine to 70° HUT, 30° HUT and back to supine. Positions were held for 3 min. Simultaneous readings of NICOM and USCOM were performed 30 s into each new position. Mean blood pressure (MBP), heart rate (HR), CO and stroke volume (SV), and thoracic fluid content (TFC) were recorded. Bland-Altman, percentage changes and analysis of variance for repeated measures were used for statistical analysis. Pre-tilt NICOM CO and SV readings (6.1 ± 1.0 L/min and 113 ± 25 ml) were higher than those from USCOM (4.1 ± 0.6 L/min and 77 ± 9 ml) (P < 0.001). Bland-Altman limits of agreement for CO were wide with a percentage error of 38 %. HUT increased MBP and HR (P < 0.001). CO and SV readings decreased with HUT. However, the percentage changes in USCOM and NICOM readings did not concur (P < 0.001). Whereas USCOM provided gravitational effect proportional changes in SV readings of 23 ± 15 % (30° half tilt) and 44 ± 11 % (70° near full tilt), NICOM changes did not being 28 ± 10 and 33 ± 11 %. TFC decreased linearly with HUT. The NICOM does not provide linear changes in SV as predicted by physiology when patients are tilted. Furthermore there is a lack of agreement with USCOM measurements at baseline and during tilting.

  3. Nexfin Noninvasive Continuous Hemodynamic Monitoring: Validation against Continuous Pulse Contour and Intermittent Transpulmonary Thermodilution Derived Cardiac Output in Critically Ill Patients

    PubMed Central

    Van De Vijver, Katrijn; De laet, Inneke; Schoonheydt, Karen; Dits, Hilde; Bein, Berthold; Malbrain, Manu L. N. G.

    2013-01-01

    Introduction. Nexfin (Bmeye, Amsterdam, Netherlands) is a noninvasive cardiac output (CO) monitor based on finger arterial pulse contour analysis. The aim of this study was to validate Nexfin CO (NexCO) against thermodilution (TDCO) and pulse contour CO (CCO) by PiCCO (Pulsion Medical Systems, Munich, Germany). Patients and Methods. In a mix of critically ill patients (n = 45), NexCO and CCO were measured continuously and recorded at 2-hour intervals during the 8-hour study period. TDCO was measured at 0–4–8 hrs. Results. NexCO showed a moderate to good (significant) correlation with TDCO (R2 0.68, P < 0.001) and CCO (R2 0.71, P < 0.001). Bland and Altman analysis comparing NexCO with TDCO revealed a bias (± limits of agreement, LA) of 0.4 ± 2.32 L/min (with 36% error) while analysis comparing NexCO with CCO showed a bias (±LA) of 0.2 ± 2.32 L/min (37% error). NexCO is able to follow changes in TDCO and CCO during the same time interval (level of concordance 89.3% and 81%). Finally, polar plot analysis showed that trending capabilities were acceptable when changes in NexCO (ΔNexCO) were compared to ΔTDCO and ΔCCO (resp., 89% and 88.9% of changes were within the level of 10% limits of agreement). Conclusion. we found a moderate to good correlation between CO measurements obtained with Nexfin and PiCCO. PMID:24319373

  4. 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

  5. An autocalibrating algorithm for non-invasive cardiac output determination based on the analysis of an arterial pressure waveform recorded with radial artery applanation tonometry: a proof of concept pilot analysis.

    PubMed

    Saugel, Bernd; Meidert, Agnes S; Langwieser, Nicolas; Wagner, Julia Y; Fassio, Florian; Hapfelmeier, Alexander; Prechtl, Luisa M; Huber, Wolfgang; Schmid, Roland M; Gödje, Oliver

    2014-08-01

    We aimed to describe and evaluate an autocalibrating algorithm for determination of cardiac output (CO) based on the analysis of an arterial pressure (AP) waveform recorded using radial artery applanation tonometry (AT) in a continuous non-invasive manner. To exemplarily describe and evaluate the CO algorithm, we deliberately selected 22 intensive care unit patients with impeccable AP waveforms from a database including AP data obtained with AT (T-Line system; Tensys Medical Inc.). When recording AP data for this prospectively maintained database, we had simultaneously noted CO measurements obtained from just calibrated pulse contour analysis (PiCCO system; Pulsion Medical Systems) every minute. We applied the autocalibrating CO algorithm to the AT-derived AP waveforms and noted the computed CO values every minute during a total of 15 min of data recording per patient (3 × 5-min intervals). These 330 AT-derived CO (AT-CO) values were then statistically compared to the corresponding pulse contour CO (PC-CO) values. Mean ± standard deviation for PC-CO and AT-CO was 7.0 ± 2.0 and 6.9 ± 2.1 L/min, respectively. The coefficient of variation for PC-CO and AT-CO was 0.280 and 0.299, respectively. Bland-Altman analysis demonstrated a bias of +0.1 L/min (standard deviation 0.8 L/min; 95% limits of agreement -1.5 to 1.7 L/min, percentage error 23%). CO can be computed based on the analysis of the AP waveform recorded with AT. In the selected patients included in this pilot analysis, a percentage error of 23% indicates clinically acceptable agreement between AT-CO and PC-CO.

  6. Single session of sprint interval training elicits similar cardiac output but lower oxygen uptake versus ramp exercise to exhaustion in men and women

    PubMed Central

    Horn, Trevor; Roverud, Garret; Sutzko, Kandice; Browne, Melissa; Parra, Cristina; Astorino, Todd A

    2016-01-01

    Sprint interval training (SIT) elicits comparable long-term adaptations versus continuous exercise training (CEX) including increased maximal oxygen uptake (VO2max) and fat utilization. However, there is limited research examining acute hemodynamic responses to SIT. The aim of this study was to examine hemodynamic responses to low-volume SIT. Active men (n=6, VO2max = 39.8 ± 1.7 mL/kg/min) and women (n=7, VO2max = 37.3 ± 5.7 mL/kg/min) performed a ramp-based VO2max test (RAMP) to determine workload for the SIT session. Subjects returned within 1 wk and completed a session of SIT consisting of six 30-s bouts of “all-out” cycling at 130% maximal workload (Wmax) interspersed with 120 s of active recovery. Continuously during RAMP and exercise and recovery in SIT, VO2 was obtained and thoracic impedance was used to estimate heart rate (HR), stroke volume (SV), and cardiac output (CO). Results revealed no significant differences in COmax (p = 0.12, 19.7 ± 2.4 L/min vs. 20.3 ± 1.8 L/min) but lower SVmax (p = 0.004, 110.4 ± 15.7 mL vs. 119.4 ± 15.5 mL) in RAMP versus SIT. HRmax from SIT (179.0 ± 11.8 b/min) was lower (p = 0.008) versus RAMP (184.4 ± 7.9 b/min). Peak VO2 (L/min) was lower (p < 0.001) in response to SIT (2.43 ± 0.82 L/min) compared to RAMP (2.84 ± 0.82 L/min). Hemodynamic variables increased linearly across SIT bouts and remained significantly elevated in recovery. Sprint interval training consisting of 3 min of supramaximal exercise elicits similar CO yet lower VO2 compared to RAMP. PMID:27785335

  7. [Cardiac support and replacement therapies].

    PubMed

    Lotz, Christopher; Roewer, Norbert; Muellenbach, Ralf M

    2016-09-01

    Circulatory support represents an integral part within the treatment of the critically ill patient. Sophisticated pharmacologic regimens help to maintain systemic perfusion pressure by increasing vascular tone as well as mediating positive inotropic effects. Besides the administration of catecholamines and phosphodiesterase-III-inhibitors, in particular the administration of levosimendan represents a promising alternative during low-cardiac-output. Nevertheless, sufficient evidence demonstrating a survival benefit for any pharmacologic regimen is nonexistent. In case pharmacological measures do not suffice mechanical cardiopulmonary support (MCS) may be used. MCS may be used during cardiopulmonary resuscitation or a "low-cardiac-output-syndrome" as bridging towards decision, recovery or long-term support. Venoarterial extracorporeal membrane oxygenation (vaECMO) may take over cardiopulmonary function and may improve survival as well as neurological outcome after cardiogenic shock or cardiopulmonary resuscitation. PMID:27631451

  8. Cardiac catheterization

    MedlinePlus

    Catheterization - cardiac; Heart catheterization; Angina - cardiac catheterization; CAD - cardiac catheterization; Coronary artery disease - cardiac catheterization; Heart valve - cardiac catheterization; Heart failure - ...

  9. 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

  10. Cardiac gated ventilation

    SciTech Connect

    Hanson, C.W. III; Hoffman, E.A.

    1995-12-31

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

  11. 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.

  12. [The Contribution of Vascular Capacity and Blood Volume to Maintain Stable Blood Circulation during General Anesthesia].

    PubMed

    Shigemi, Kenji

    2016-05-01

    To maintain proper cardiac preload is one of the most effective procedures for the systemic circulation remaining stable. In particular, the balance between vascular capacity and total blood volume must be maintained within appropriate range by the administration of fluids, blood and/or vasoactive drugs with mean circulatory filling pressure (Pmcf), central venous pressure (CVP) or stroke volume variation (SVV). End-diastolic left ventricular volume (Ved) is theoretically the best index of cardiac preload; however, without transesophageal echocardbalanceiogram we cannot directly monitor Ved during anesthesia. The infused fluid volume remaining in intravascular space, the vascular capacity controlled by autonomic nervous system and/or vasoactive agents, and the unstressed blood volume properly mobilized to excess blood volume are the crucial factors to maintain cardiac output The knowledge of vascular physiology contribute the decision making to manipulate such factors to control blood circulation during general anesthesia. For example, CVP is usually maintained in the narrow range and seems to be stable; however, it must be changed just after the circulatory disturbances, such as acute bleeding, blood transfusion, and fluid infusion, and followed by gradual returning to initial value, because of the solid mechanism to preserve cardiac output

  13. Neurologic complications of cardiac tumors.

    PubMed

    Roeltgen, David; Kidwell, Chelsea S

    2014-01-01

    Cardiac tumors are an uncommon cause for neurologic disease, but if undiagnosed can be associated with devastating neurologic consequences. Primary cardiac tumors, both benign and neoplastic, and metastatic tumors occur. Primary cardiac tumors are more likely to be associated with neurologic embolic complications. Metastatic cardiac tumors are more likely to be associated with valvular distraction, arrhythmia, diminished cardiac output and indirect neurological dysfunction. Primary and metastatic cardiac tumors may result in cerebral metastatic disease. Atrial myxoma, a benign primary cardiac tumor, is the most common cardiac tumor associated with neurologic disease, and most commonly causes cerebral embolization and stroke. The use of thrombolytic therapy for these strokes is controversial. Additionally, delayed manifestations, including aneurysm formation and intracranial hemorrhage, are possible. Aneurysm formation has been described as occurring after removal of the primary tumor. The availability of noninvasive cardiac imaging has significantly helped decrease the neurologic morbidity of cardiac tumors and has led to frequent successful intervention. PMID:24365298

  14. Validation of stroke volume and cardiac output by electrical interrogation of the brachial artery in normals: assessment of strengths, limitations, and sources of error.

    PubMed

    Bernstein, Donald P; Henry, Isaac C; Lemmens, Harry J; Chaltas, Janell L; DeMaria, Anthony N; Moon, James B; Kahn, Andrew M

    2015-12-01

    The goal of this study is to validate a new, continuous, noninvasive stroke volume (SV) method, known as transbrachial electrical bioimpedance velocimetry (TBEV). TBEV SV was compared to SV obtained by cardiac magnetic resonance imaging (cMRI) in normal humans devoid of clinically apparent heart disease. Thirty-two (32) volunteers were enrolled in the study. Each subject was evaluated by echocardiography to assure that no aortic or mitral valve disease was present. Subsequently, each subject underwent electrical interrogation of the brachial artery by means of a high frequency, low amplitude alternating current. A first TBEV SV estimate was obtained. Immediately after the initial TBEV study, subjects underwent cMRI, using steady-state precession imaging to obtain a volumetric estimate of SV. Following cMRI, the TBEV SV study was repeated. Comparing the cMRI-derived SV to that of TBEV, the two TBEV estimates were averaged and compared to the cMRI standard. CO was computed as the product of SV and heart rate. Statistical methods consisted of Bland-Altman and linear regression analysis. TBEV SV and CO estimates were obtained in 30 of the 32 subjects enrolled. Bland-Altman analysis of pre- and post-cMRI TBEV SV showed a mean bias of 2.87 % (2.05 mL), precision of 13.59% (11.99 mL) and 95% limits of agreement (LOA) of +29.51% (25.55 mL) and -23.77% (-21.45 mL). Regression analysis for pre- and post-cMRI TBEV SV values yielded y = 0.76x + 25.1 and r(2) = 0.71 (r = 0.84). Bland-Altman analysis comparing cMRI SV with averaged TBEV SV showed a mean bias of -1.56% (-1.53 mL), precision of 13.47% (12.84 mL), 95% LOA of +24.85% (+23.64 mL) and -27.97% (-26.7 mL) and percent error = 26.2 %. For correlation analysis, the regression equation was y = 0.82x + 19.1 and correlation coefficient r(2) = 0.61 (r = 0.78). Bland-Altman analysis of averaged pre- and post-cMRI TBEV CO versus cMRI CO yielded a mean bias of 5.01% (0.32 L min(-1)), precision of 12.85% (0.77 L min(-1)), 95% LOA

  15. Reverse Cardiac Remodeling: A Marker of Better Prognosis in Heart Failure

    PubMed Central

    Reis, José Rosino de Araújo Rocha; Cardoso, Juliano Novaes; Cardoso, Cristina Martins dos Reis; Pereira-Barretto, Antonio Carlos

    2015-01-01

    In heart failure syndrome, myocardial dysfunction causes an increase in neurohormonal activity, which is an adaptive and compensatory mechanism in response to the reduction in cardiac output. Neurohormonal activity is initially stimulated in an attempt to maintain compensation; however, when it remains increased, it contributes to the intensification of clinical manifestations and myocardial damage. Cardiac remodeling comprises changes in ventricular volume as well as the thickness and shape of the myocardial wall. With optimized treatment, such remodeling can be reversed, causing gradual improvement in cardiac function and consequently improved prognosis. PMID:26131706

  16. Maintaining Transparency

    PubMed Central

    Beebe, David C.

    2008-01-01

    The lens and cornea are transparent and usually avascular. Controlling nutrient supply while maintaining transparency is a physiological challenge for both tissues. During sleep and with contact lens wear the endothelial layer of the cornea may become hypoxic, compromising its ability to maintain corneal transparency. The mechanism responsible for establishing the avascular nature of the corneal stroma is unknown. In several pathological conditions, the stroma can be invaded by abnormal, leaky vessels, leading to opacification. Several molecules that are likely to help maintain the avascular nature of the corneal stroma have been identified, although their relative contributions remain to be demonstrated. The mammalian lens is surrounded by capillaries early in life. After the fetal vasculature regresses, the lens resides in a hypoxic environment. Hypoxia is likely to be required to maintain lens transparency. The vitreous body may help to maintain the low oxygen level around the lens. The hypothesis is presented that many aspects of the aging of the lens, including increased hardening, loss of accommodation (presbyopia), and opacification of the lens nucleus, are caused by exposure to oxygen. Testing this hypothesis may lead to prevention for nuclear cataract and insight into the mechanisms of lens aging. Although they are both transparent, corneal pathology is associated with an insufficient supply of oxygen, while lens pathology may involve excessive exposure to oxygen. PMID:17920963

  17. 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 ...

  18. 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

  19. Autocalibrating pulse contour analysis based on radial artery applanation tonometry for continuous non-invasive cardiac output monitoring in intensive care unit patients after major gastrointestinal surgery--a prospective method comparison study.

    PubMed

    Wagner, J Y; Langemann, M; Schön, G; Kluge, S; Reuter, D A; Saugel, B

    2016-05-01

    The T-Line(®) system (Tensys(®) Medical Inc., San Diego, CA, USA) non-invasively estimates cardiac output (CO) using autocalibrating pulse contour analysis of the radial artery applanation tonometry-derived arterial waveform. We compared T-Line CO measurements (TL-CO) with invasively obtained CO measurements using transpulmonary thermodilution (TDCO) and calibrated pulse contour analysis (PC-CO) in patients after major gastrointestinal surgery. We compared 1) TL-CO versus TD-CO and 2) TL-CO versus PC-CO in 27 patients treated in the intensive care unit (ICU) after major gastrointestinal surgery. For the assessment of TD-CO and PC-CO we used the PiCCO(®) system (Pulsion Medical Systems SE, Feldkirchen, Germany). Per patient, we compared two sets of TD-CO and 30 minutes of PC-CO measurements with the simultaneously recorded TL-CO values using Bland-Altman analysis. The mean of differences (± standard deviation; 95% limits of agreement) between TL-CO and TD-CO was -0.8 (±1.6; -4.0 to +2.3) l/minute with a percentage error of 45%. For TL-CO versus PC-CO, we observed a mean of differences of -0.4 (±1.5; -3.4 to +2.5) l/minute with a percentage error of 43%. In ICU patients after major gastrointestinal surgery, continuous non-invasive CO measurement based on autocalibrating pulse contour analysis of the radial artery applanation tonometry-derived arterial waveform (TL-CO) is feasible in a clinical study setting. However, the agreement of TL-CO with TD-CO and PC-CO observed in our study indicates that further improvements are needed before the technology can be recommended for clinical use in these patients.

  20. [Cardiac failure in endocrine diseases].

    PubMed

    Hashizume, K

    1993-05-01

    Several endocrine diseases show the symptoms of cardiac failure. Among them, patients with acromegaly show a specific cardiomyopathy which results in a severe left-sided cardiac failure. Hypoparathyroidism also induces cardiac failure, which is resulted from hypocalcemia and low levels of serum parathyroid hormone. In the cases of hypothyroidism, the patients with myxedemal coma show a severe cardiac failure, which is characterized by disturbance of central nervous system, renal function, and cardiac function. In the patients with thyroid crisis (storm), the cardiac failure comes from the great reduction of cardiac output with dehydration. The reduction of circulation volume, observed in the patients with pheochromocytoma easily induces cardiac failure (shock) just after the removal of adrenal tumor. In patients with malignant carcinoid syndrome, right-sided ventricular failure which may be occurred through the actions of biogenic amines is observed. PMID:8331806

  1. Cardiac rehabilitation

    MedlinePlus

    ... Coronary artery disease - cardiac rehab; Angina - cardiac rehab; Heart failure - cardiac rehab ... have had: Heart attack Coronary heart disease (CHD) Heart failure Angina (chest pain) Heart or heart valve surgery ...

  2. Cardiac Innervation and Sudden Cardiac Death

    PubMed Central

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

    2015-01-01

    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-hours) and long term (days-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 (SCD). Transdifferentiation of neurons in heart failure, functional denervation, cardiac and extra-cardiac neural remodeling have 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 provides a rational mechanistic basis for development of neuraxial therapies for preventing SCD 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

  3. 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.

  4. External cardiac compression may be harmful in some scenarios of pulseless electrical activity.

    PubMed

    Hogan, T S

    2012-10-01

    Pulseless electrical activity occurs when organised or semi-organised electrical activity of the heart persists but the product of systemic vascular resistance and the increase in systemic arterial flow generated by the ejection of the left venticular stroke volume is not sufficient to produce a clinically detectable pulse. Pulseless electrical activity encompasses a very heterogeneous variety of severe circulatory shock states ranging in severity from pseudo-cardiac arrest to effective cardiac arrest. Outcomes of cardiopulmonary resuscitation for pulseless electrical activity are generally poor. Impairment of cardiac filling is the limiting factor to cardiac output in many scenarios of pulseless electrical activity, including extreme vasodilatory shock states. There is no evidence that external cardiac compression can increase cardiac output when impaired cardiac filling is the limiting factor to cardiac output. If impaired cardiac filling is the limiting factor to cardiac output and the heart is effectively ejecting all the blood returning to it, then external cardiac compression can only increase cardiac output if it increases venous return and cardiac filling. Repeated cardiac compression asynchronous with the patient's cardiac cycle and raised mean intrathoracic pressure due to chest compression can be expected to reduce rather than to increase cardiac filling and therefore to reduce rather than to increase cardiac output in such circumstances. The hypothesis is proposed that the performance of external cardiac compression will have zero or negative effect on cardiac output in pulseless electrical activity when impaired cardiac filling is the limiting factor to cardiac output. External cardiac compression may be both directly and indirectly harmful to significant sub-groups of patients with pulseless electrical activity. We have neither evidence nor theory to provide comfort that external cardiac compression is not harmful in many scenarios of pulseless

  5. Cardiac arrest

    MedlinePlus

    ... Article.jsp. Accessed June 16, 2014. Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening ... PA: Elsevier Saunders; 2011:chap 63. Myerburg RJ, Castellanos A. Cardiac arrest and audden aardiac death. In: ...

  6. Control system maintains selected liquid level

    NASA Technical Reports Server (NTRS)

    Bergeson, R. L.; Schuck, J. W.

    1966-01-01

    Single-sensor control system maintains liquid hydrogen at a preselected desired level within a tank, regardless of boiloff. It calibrates output in percentage. Thus, when the fuel is at the desired level, the system output will indicate 100 percent regardless of what percent of tank capacity the fuel has reached.

  7. Cardiac Imaging In Athletes.

    PubMed

    Khan, Asaad A; Safi, Lucy; Wood, Malissa

    2016-01-01

    Athletic heart syndrome refers to the physiological and morphological changes that occur in a human heart after repetitive strenuous physical exercise. Examples of exercise-induced changes in the heart include increases in heart cavity dimensions, augmentation of cardiac output, and increases in heart muscle mass. These cardiac adaptations vary based on the type of exercise performed and are often referred to as sport-specific cardiac remodeling. The hemodynamic effects of endurance and strength training exercise lead to these adaptations. Any abnormalities in chamber dilatation and left ventricular function usually normalize with cessation of exercise. Athletic heart syndrome is rare and should be differentiated from pathologic conditions such as hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia when assessing a patient for athletic heart syndrome. This paper describes specific adaptations that occur in athletic heart syndrome and tools to distinguish between healthy alterations versus underlying pathology. PMID:27486490

  8. Cardiac Imaging In Athletes

    PubMed Central

    Khan, Asaad A.; Safi, Lucy; Wood, Malissa

    2016-01-01

    Athletic heart syndrome refers to the physiological and morphological changes that occur in a human heart after repetitive strenuous physical exercise. Examples of exercise-induced changes in the heart include increases in heart cavity dimensions, augmentation of cardiac output, and increases in heart muscle mass. These cardiac adaptations vary based on the type of exercise performed and are often referred to as sport-specific cardiac remodeling. The hemodynamic effects of endurance and strength training exercise lead to these adaptations. Any abnormalities in chamber dilatation and left ventricular function usually normalize with cessation of exercise. Athletic heart syndrome is rare and should be differentiated from pathologic conditions such as hypertrophic cardiomyopathy, left ventricular noncompaction, and arrhythmogenic right ventricular dysplasia when assessing a patient for athletic heart syndrome. This paper describes specific adaptations that occur in athletic heart syndrome and tools to distinguish between healthy alterations versus underlying pathology. PMID:27486490

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

    PubMed

    Choi, Ji Won; Joo Ahn, Hyun; 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.

  10. Cardiac Sarcoidosis.

    PubMed

    Birnie, David; Ha, Andrew C T; Gula, Lorne J; Chakrabarti, Santabhanu; Beanlands, Rob S B; Nery, Pablo

    2015-12-01

    Studies suggest clinically manifest cardiac involvement occurs in 5% of patients with pulmonary/systemic sarcoidosis. The principal manifestations of cardiac sarcoidosis (CS) are conduction abnormalities, ventricular arrhythmias, and heart failure. Data indicate that an 20% to 25% of patients with pulmonary/systemic sarcoidosis have asymptomatic (clinically silent) cardiac involvement. An international guideline for the diagnosis and management of CS recommends that patients be screened for cardiac involvement. Most studies suggest a benign prognosis for patients with clinically silent CS. Immunosuppression therapy is advocated for clinically manifest CS. Device therapy, with implantable cardioverter defibrillators, is recommended for some patients.

  11. Cardiac transplantation.

    PubMed

    Shanewise, Jack

    2004-12-01

    Cardiac transplantation is a proven, accepted mode of therapy for selected patients with end-stage heart failure, but the inadequate number of suitable donor hearts available ultimately limits its application. This chapter reviews adult cardiac transplantation, with an emphasis on the anesthetic considerations of the heart transplant operation itself.

  12. 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

  13. 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

  14. 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

  15. Cardiac amyloidosis

    MedlinePlus

    ... the way electrical signals move through the heart (conduction system). This can lead to abnormal heartbeats ( arrhythmias ) ... due to medicine) Sick sinus syndrome Symptomatic cardiac conduction system disease (arrhythmias related to abnormal conduction of ...

  16. Cardiac Sarcoidosis

    MedlinePlus

    ... is Cardiac Sarcoidosis? Sarcoidosis is a poorly understood disease that commonly affects the lungs. It can also involve the lymph nodes, liver, spleen, eyes, skin, bones, salivary glands and heart. ...

  17. Cardiac Regenerative Capacity and Mechanisms

    PubMed Central

    Kikuchi, Kazu; Poss, Kenneth D.

    2013-01-01

    The heart holds the monumental yet monotonous task of maintaining circulation. Although cardiac function is critical to other organs and to life itself, mammals are not equipped with significant natural capacity to replace heart muscle that has been lost by injury. This deficiency plays a role in leaving millions worldwide each year vulnerable to heart failure. By contrast, certain other vertebrate species like zebrafish are strikingly good at heart regeneration. A cellular and molecular understanding of endogenous regenerative mechanisms, combined with advances in methodology to transplant cells, together project a future in which cardiac muscle regeneration can be therapeutically stimulated in injured human hearts. This review will focus on what has been discovered recently about cardiac regenerative capacity and how natural mechanisms of heart regeneration in model systems are stimulated and maintained. PMID:23057748

  18. High-output heart failure in a newborn.

    PubMed

    Mascarenhas, Maria Inês; Moniz, Marta; Ferreira, Sofia; Goulão, Augusto; Barroso, Rosalina

    2012-07-10

    High-output cardiac failure is rare in newborns. Emergent diagnosis and management of this pathology is crucial. We report the case of a child, currently 12-months old; obstetric background is non-contributory. Clinic observation on D1 was normal except for the presence of a systolic cardiac murmur; cardiological evaluation revealed mild ventricular dysfunction of the right ventricle. On the third day of life, she developed cardiac failure with gallop rhythm, hepatomegaly and a murmur in the anterior fontanel; an echocardiogram confirmed clinic aggravation with biventricular dysfunction and right cavities and superior vena cava dilatation. The cranial MRI confirmed the presence of a pial arteriovenous malformation (AVM) involving the anterior and middle cerebral arteries with an associated fronto-parietal ischaemic lesion. The infant underwent embolisations of AVM with successful flow reduction and cardiac failure improvement. The multidisciplinary follow-up showed no cardiac dysfunction or permanent lesions but confirmed a severe psycho-motor delay and left hemiparesia.

  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. Quality Control Systems in Cardiac Aging

    PubMed Central

    Quarles, Ellen K; Dai, Dao-Fu; Tocchi, Autumn; Basisty, Nathan; Gitari, Lemuel; Rabinovitch, Peter S

    2015-01-01

    Cardiac aging is an intrinsic process that results in impaired cardiac function, along with cellular and molecular changes. These degenerative changes are intimately associated with quality control mechanisms. This review provides a general overview of the clinical and cellular changes which manifest in cardiac aging, and the quality control mechanisms involved in maintaining homeostasis and retarding aging. These mechanisms include autophagy, ubiquitin-mediated turnover, apoptosis, mitochondrial quality control and cardiac matrix homeostasis. Finally, we discuss aging interventions that have been observed to impact cardiac health outcomes. These include caloric restriction, rapamycin, resveratrol, GDF11, mitochondrial antioxidants and cardiolipin-targeted therapeutics. A greater understanding of the quality control mechanisms that promote cardiac homeostasis will help to understand the benefits of these interventions, and hopefully lead to further improved therapeutic modalities. PMID:25702865

  1. [Stem cells and cardiac regeneration].

    PubMed

    Perez Millan, Maria Ines; Lorenti, Alicia

    2006-01-01

    Stem cells are defined by virtue of their functional attributes: absence of tissue specific differentitated markers, capable of proliferation, able to self-maintain the population, able to produce a large number of differentiated, functional progeny, able to regenerate the tissue after injury. Cell therapy is an alternative for the treatment of several diseases, like cardiac diseases (cell cardiomyoplasty). A variety of stem cells could be used for cardiac repair: from cardiac and extracardiac sources. Each cell type has its own profile of advantages, limitations, and practicability issues in specific clinical settings. Differentiation of bone marrow stem cells to cardiomyocyte-like cells have been observed under different culture conditions. The presence of resident cardiac stem cell population capable of differentiation into cardiomyocyte or vascular lineage suggests that these cells could be used for cardiac tissue repair, and represent a great promise for clinical application. Stem cells mobilization by cytokines may also offer a strategy for cardiac regeneration. The use of stem cells (embryonic and adult) may hold the key to replacing cells lost in many devastating diseases. This potential benefit is a major focus for stem cell research.

  2. Biomechanics of Cardiac Function

    PubMed Central

    Voorhees, Andrew P.; Han, Hai-Chao

    2015-01-01

    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. Pneumopericardium: an unusual cause for cardiac arrest.

    PubMed

    Djaiani, G; Major, E

    1998-06-01

    A 1-year-old boy breathing via a T-piece system and recovering from meningococcal septicaemia in the intensive care unit suffered a severe bout of coughing and developed bilateral pneumothoraces and tension pneumopericardium resulting in electromechanical dissociation and asystole. Conventional cardiopulmonary resuscitation and adrenaline boluses were unsuccessful. Administration of 20 ml.kg-1 of colloid and 3 mmol.kg-1 of sodium bicarbonate solutions produced instantaneous return of cardiac, output. The deleterious effects of cardiac tamponade appeared to decrease with increasing cardiac filling pressures. The patient was managed conservatively and he made a full recovery with no signs of residual neurological deficit. PMID:9709145

  4. Governmentally amplified output volatility

    NASA Astrophysics Data System (ADS)

    Funashima, Yoshito

    2016-11-01

    Predominant government behavior is decomposed by frequency into several periodic components: updating cycles of infrastructure, Kuznets cycles, fiscal policy over business cycles, and election cycles. Little is known, however, about the theoretical impact of such cyclical behavior in public finance on output fluctuations. Based on a standard neoclassical growth model, this study intends to examine the frequency at which public investment cycles are relevant to output fluctuations. We find an inverted U-shaped relationship between output volatility and length of cycle in public investment. This implies that periodic behavior in public investment at a certain frequency range can cause aggravated output resonance. Moreover, we present an empirical analysis to test the theoretical implication, using the U.S. data in the period from 1968 to 2015. The empirical results suggest that such resonance phenomena change from low to high frequency.

  5. Cardiac complications in thalassemia major.

    PubMed

    Auger, Dominique; Pennell, Dudley J

    2016-03-01

    The myocardium is particularly susceptible to complications from iron loading in thalassemia major. In the first years of life, severe anemia leads to high-output cardiac failure and death if not treated. The necessary supportive blood transfusions create loading of iron that cannot be naturally excreted, and this iron accumulates within tissues, including the heart. Free unbound iron catalyzes the formation of toxic hydroxyl radicals, which damage cells and cause cardiac dysfunction. Significant cardiac siderosis may present by the age of 10 and may lead to acute clinical heart failure, which must be treated urgently. Atrial fibrillation is the most frequently encountered iron-related arrhythmia. Iron chelation is effective at removing iron from the myocardium, at the expense of side effects that hamper compliance to therapy. Monitoring of myocardial iron content is mandatory for clinical management of cardiac risk. T2* cardiac magnetic resonance measures myocardial iron and is the strongest biomarker for prediction of heart failure and arrhythmic events. It has been calibrated to human myocardial tissue iron concentration and is highly reproducible across all magnetic resonance scanner vendors. As survival and patient age increases, endothelial dysfunction and diabetes may become new factors in the cardiovascular health of thalassemia patients. Promising new imaging technology and therapies could ameliorate the long-term prognosis.

  6. 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

  7. Is there a future for minimally invasive cardiac surgery?

    PubMed

    Mack, M J

    1999-11-01

    Although cardiac surgery has made significant contributions to the cardiac health of millions of patients over the past 40 years, it has evolved from an 'emerging growth' to a 'mature' industry. Along with this maturation has come an 'inertia of success' and lack of innovation. Minimally invasive cardiac surgery is an attempt to develop more patient friendly cardiac procedures yet maintain the superior long term results of conventional cardiac surgery. A broad spectrum of new surgical techniques and technical innovations has been fostered. The impact has been not only that of 'discontinuous innovation' of a new type of cardiac surgery but also a significant 'coat-tail' effect of 'upgrading' conventional cardiac surgery. It is difficult to adapt to change. But if we maintain an open-mindedness toward evolution with a firm foundation in proven standards, our patients will be the beneficiaries.

  8. 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.

  9. Sudden Cardiac Arrest in Pediatrics.

    PubMed

    Scheller, RoseAnn L; Johnson, Laurie; Lorts, Angela; Ryan, Thomas D

    2016-09-01

    Sudden cardiac arrest (SCA) in the pediatric population is a rare and potentially devastating occurrence. An understanding of the differential diagnosis for the etiology of the cardiac arrest allows for the most effective emergency care and provides the patient with the best possible outcome. Pediatric SCA can occur with or without prodromal symptoms and may occur during exercise or rest. The most common cause is arrhythmia secondary to an underlying channelopathy, cardiomyopathy, or myocarditis. After stabilization, evaluation should include electrocardiogram, chest radiograph, and echocardiogram. Management should focus on decreasing the potential for recurring arrhythmia, maintaining cardiac preload, and thoughtful medication use to prevent exacerbation of the underlying condition. The purpose of this review was to provide the emergency physician with a concise and current review of the incidence, differential diagnosis, and management of pediatric patients presenting with SCA. PMID:27585126

  10. Maintaining Your Health

    MedlinePlus

    ... center but can also be done in nursing facilities, hospitals, or at home. Book a PFF Ambassador for your event. Call 844.TalkPFF > Life with PF About PF Treatment Options Clinical Trials Maintaining Your Health Find Medical Care Support Groups PFF ...

  11. Direct reprogramming of fibroblasts into cardiomyocytes for cardiac regenerative medicine.

    PubMed

    Fu, Ji-Dong; Srivastava, Deepak

    2015-01-01

    Cardiac fibroblasts play critical roles in maintaining normal cardiac function and in cardiac remodeling during pathological conditions such as myocardial infarction (MI). Adult cardiomyocytes (CMs) have little to no regenerative capacity; damaged CMs in the heart after MI are replaced by cardiac fibroblasts that become activated and transform into myofibroblasts, which preserves the structural integrity. Unfortunately, this process typically causes fibrosis and reduces cardiac function. Directly reprogramming adult cardiac fibroblasts into induced CM-like cells (iCMs) holds great promise for restoring heart function. Direct cardiac reprogramming also provides a new research model to investigate which transcription factors and microRNAs control the molecular network that guides cardiac cell fate. We review the approaches and characterization of in vitro and in vivo reprogrammed iCMs from different laboratories, and outline the future directions needed to translate this new approach into a practical therapy for damaged hearts.

  12. Cardiac conduction system

    MedlinePlus

    The cardiac conduction system is a group of specialized cardiac muscle cells in the walls of the heart that send signals ... to contract. The main components of the cardiac conduction system are the SA node, AV node, bundle ...

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. Direct bonded space maintainers.

    PubMed

    Santos, V L; Almeida, M A; Mello, H S; Keith, O

    1993-01-01

    The aim of this study was to evaluate clinically a bonded space maintainer, which would reduce chair-side time and cost. Sixty appliances were fabricated from 0.7 mm stainless steel round wire and bonded using light-cured composite to the two teeth adjacent to the site of extraction of a posterior primary tooth. Twenty males and sixteen females (age range 5-9-years-old) were selected from the Pedodontic clinic of the State University of Rio de Janeiro. The sixty space maintainers were divided into two groups according to the site in which they were placed: a) absent first primary molar and b) absent second primary molar. Impressions and study models were obtained prior to and 6 months after bonding the appliances. During this period only 8.3% of failures were observed, most of them from occlusal or facial trauma. Student t-test did not show statistically significant alterations in the sizes of the maintained spaces during the trial period.

  18. 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.

  19. 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

  20. Climate Model Output Rewriter

    SciTech Connect

    Taylor, K. E.; Doutriaux, C.

    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 an 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.

  1. Climate Model Output Rewriter

    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

  2. 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

  3. Corticosteroids Are Essential for Maintaining Cardiovascular Function in Male Mice.

    PubMed

    Cruz-Topete, Diana; Myers, Page H; Foley, Julie F; Willis, Monte S; Cidlowski, John A

    2016-07-01

    Activation of the hypothalamic-pituitary-adrenal axis results in the release of hormones from the adrenal glands, including glucocorticoids and mineralocorticoids. The physiological association between corticosteroids and cardiac disease is becoming increasingly recognized; however, the mechanisms underlying this association are not well understood. To determine the biological effects of corticosteroids on the heart, we investigated the impact of adrenalectomy in C57BL/6 male mice. Animals were adrenalectomized (ADX) at 1 month of age and maintained for 3-6 months after surgery to evaluate the effects of long-term adrenalectomy on cardiac function. Morphological evaluation suggested that ADX mice showed significantly enlarged hearts compared with age-matched intact controls. These changes in morphology correlated with deficits in left ventricular (LV) function and electrocardiogram (ECG) abnormalities in ADX mice. Correlating with these functional defects, gene expression analysis of ADX hearts revealed aberrant expression of a large cohort of genes associated with cardiac hypertrophy and arrhythmia. Combined corticosterone and aldosterone replacement treatment prevented the emergence of cardiac abnormalities in ADX mice, whereas corticosterone replacement prevented the effects of adrenalectomy on LV function but did not block the emergence of ECG alterations. Aldosterone replacement did not preserve the LV function but prevented ECG abnormalities. Together, the data indicate that adrenal glucocorticoids and mineralocorticoids either directly or indirectly have selective effects in the heart and their signaling pathways are essential in maintaining normal cardiac function. PMID:27219275

  4. 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.

  5. Imaging of cardiac sarcoidosis.

    PubMed

    Erthal, Fernanda; Juneau, Daniel; Lim, Siok P; Dwivedi, Girish; Nery, Pablo B; Birnie, David; Beanlands, Rob S

    2016-09-01

    Sarcoidosis is a multisystem inflammatory disease. Cardiac involvement is described in up to 50% of the cases. The disease spectrum is wide and cardiac manifestations ranges from being asymptomatic to heart failure, arrhythmias and sudden cardiac death. The diagnosis of cardiac sarcoidosis can be challenging due to its non-specific nature and the focal involvement of the heart. In this review, we discuss the utility of a stepwise approach with multimodality cardiac imaging in the diagnosis and management of CS. PMID:27225318

  6. Cardiac mechanoenergetic cost of elevated plasma viscosity after moderate hemodilution.

    PubMed

    Chatpun, Surapong; Cabrales, Pedro

    2010-01-01

    The purpose of this study was to investigate how plasma viscosity affects cardiac and vascular function during moderate hemodilution. Twelve anesthetized hamsters were hemodiluted by 40% of blood volume with two different viscosity plasma expanders. Experimental groups were based on the plasma expander viscosity, namely: high viscosity plasma expander (HVPE, 6.3 mPa · s) and low viscosity plasma expander (LVPE, 2.2 mPa · s). Left ventricular (LV) function was intracardiacally measured with a high temporal resolution miniaturized conductance catheter and concurrent pressure-volume results were used to calculate different LV indices. Independently of the plasma expander, hemodilution decreased hematocrit to 28% in both groups. LVPE hemodilution reduced whole blood viscosity by 40% without changing plasma viscosity, while HVPE hemodilution reduced whole blood viscosity by 23% and almost doubled plasma viscosity relative to baseline. High viscosity plasma expander hemodilution significantly increased cardiac output, stroke volume and stroke work compared to baseline, whereas LVPE hemodilution did not. Furthermore, an increase in plasma viscosity during moderate hemodilution produced a higher energy transfer per unit volume of ejected blood. Systemic vascular resistance decreased after hemodilution in both groups. Counter-intuitively, HVPE hemodilution showed lower vascular resistance and vascular hindrance than LVPE hemodilution. This result suggests that geometrical changes in the circulatory system are induced by the increase in plasma viscosity. In conclusion, an increase in plasma viscosity after moderate hemodilution directly influenced cardiac and vascular function by maintaining hydraulic power and reducing systemic vascular resistance through vasodilation. PMID:21084746

  7. Role of breathing in cardiac performance: experimental and mathematical models

    NASA Astrophysics Data System (ADS)

    Tran, Binh Q.; Hoffman, Eric A.

    1999-05-01

    Due to the close proximity of the heart and lungs within a closed chest environment, we expect breathing to affect various cardiac performance parameters and hence cardiac output. We present an integrative approach to study heart-lung interactions, combining a mathematical formulation of the circulation system with imaging techniques using echo-planar magnetic resonance imaging (EPI) and dynamic x-ray CT (EBCT). We hypothesize that appropriate synchronization of mechanical ventilation to cardiac-cycle specific events can improve cardiac function, i.e. stroke volume (SV) and cardiac output (CO). Computational and experimental results support the notion that heart-lung interaction, leading to altered cardiac output associated with inspiration/expiration, is not directly associated with lung inflation/deflation and thus is felt to be more influenced by pleural pressure changes. The mathematical model of the circulation demonstrates the importance of cardiac-cycle specific timing of ventilation on cardiac function and matches with experimentally observed relationships found in animal models studied via EBCT and human studies using EPI. Results show that positive pressure mechanical ventilation timed to systolic events may increase SV and CO by up to 30%, mainly by increased filling of the ventricles during diastole. Similarly, negative pressure (spontaneous) respiration has its greatest effect on ventricular diastolic filling. Cardiac-gated mechanical ventilation may provide sufficient cardiac augmentation to warrant further investigation as a minimally-invasive technique for temporary cardiac assist. Through computational modeling and advanced imaging protocols, we were able to uniquely study heart-lung interactions within the intact milieu of the never-invaded thorax.

  8. CARDIAC MUSCLE

    PubMed Central

    Sommer, Joachim R.; Johnson, Edward A.

    1968-01-01

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

  9. Cardiac matrix: a clue for future therapy.

    PubMed

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

    2013-12-01

    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 (EM) 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 EM 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

  10. 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

  11. Modes of induced cardiac arrest: hyperkalemia and hypocalcemia--literature review.

    PubMed

    Oliveira, Marcos Aurélio Barboza de; Brandi, Antônio Carlos; Santos, Carlos Alberto dos; 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.

  12. 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.

  13. Nuclear cardiac blood volume detecting apparatus

    SciTech Connect

    Wagner, H.N.; Wake, R.H.

    1980-04-15

    A built up image illustrating blood volume in the heart versus time taken over many cardiac cycles is produced by continuously displaying a graph of cumulative data indicating the amount of radioactivity from a tracer in the blood detected in the heart during each of a series of intervals into which the average cardiac period is divided. The parallel lines of a raster scan display correspond respectively to the memory channels. The count stored in a particular memory channel causes the video signal for the corresponding line to be maintained at a binary level for a corresponding time interval thus generating a bar graph in which the length of each bar indicates the amount of radioactivity sensed during the corresponding interval of the cardiac cycle. As each memory channel accumulates radioactivity data with each successive cardiac cycle, each bar displayed in the bar graph lengthens to indicate the cumulative activity until an interpretable curve is obtained.

  14. Non-Coding RNAs in Cardiac Aging.

    PubMed

    Wang, Hui; Bei, Yihua; Shi, Jing; Xiao, Junjie; Kong, Xiangqing

    2015-01-01

    Aging has a remarkable impact on the function of the heart, and is independently associated with increased risk for cardiovascular diseases. Cardiac aging is an intrinsic physiological process that results in impaired cardiac function, along with lots of cellular and molecular changes. Non-coding RNAs include small transcripts, such as microRNAs and a wide range of long non-coding RNAs (lncRNAs). Emerging evidence has revealed that non-coding RNAs acted as powerful and dynamic modifiers of cardiac aging. This review aims to provide a general overview of non-coding RNAs implicated in cardiac aging, and the underlying mechanisms involved in maintaining homeo-stasis and retarding aging.

  15. 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.

  16. Nutritional status and cardiac autophagy.

    PubMed

    Ahn, Jihyun; Kim, Jaetaek

    2013-02-01

    Autophagy is necessary for the degradation of long-lasting proteins and nonfunctional organelles, and is activated to promote cellular survival. However, overactivation of autophagy may deplete essential molecules and organelles responsible for cellular survival. Lifelong calorie restriction by 40% has been shown to increase the cardiac expression of autophagic markers, which suggests that it may have a cardioprotective effect by decreasing oxidative damage brought on by aging and cardiovascular diseases. Although cardiac autophagy is critical to regulating protein quality and maintaining cellular function and survival, increased or excessive autophagy may have deleterious effects on the heart under some circumstances, including pressure overload-induced heart failure. The importance of autophagy has been shown in nutrient supply and preservation of energy in times of limitation, such as ischemia. Some studies have suggested that a transition from obesity to metabolic syndrome may involve progressive changes in myocardial inflammation, mitochondrial dysfunction, fibrosis, apoptosis, and myocardial autophagy.

  17. Effects of perhexiline-induced fuel switch on the cardiac proteome and metabolome.

    PubMed

    Yin, Xiaoke; Dwyer, Joseph; Langley, Sarah R; Mayr, Ursula; Xing, Qiuru; Drozdov, Ignat; Nabeebaccus, Adam; Shah, Ajay M; Madhu, Basetti; Griffiths, John; Edwards, Lindsay M; Mayr, Manuel

    2013-02-01

    Perhexiline is a potent anti-anginal drug used for treatment of refractory angina and other forms of heart disease. It provides an oxygen sparing effect in the myocardium by creating a switch from fatty acid to glucose metabolism through partial inhibition of carnitine palmitoyltransferase 1 and 2. However, the precise molecular mechanisms underlying the cardioprotective effects elicited by perhexiline are not fully understood. The present study employed a combined proteomics, metabolomics and computational approach to characterise changes in murine hearts upon treatment with perhexiline. According to results based on difference in-gel electrophoresis, the most profound change in the cardiac proteome related to the activation of the pyruvate dehydrogenase complex. Metabolomic analysis by high-resolution nuclear magnetic resonance spectroscopy showed lower levels of total creatine and taurine in hearts of perhexiline-treated mice. Creatine and taurine levels were also significantly correlated in a cross-correlation analysis of all metabolites. Computational modelling suggested that far from inducing a simple shift from fatty acid to glucose oxidation, perhexiline may cause complex rebalancing of carbon and nucleotide phosphate fluxes, fuelled by increased lactate and amino acid uptake, to increase metabolic flexibility and to maintain cardiac output. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism". PMID:23277191

  18. Maintaining the unmethylated state

    PubMed Central

    2013-01-01

    Background A remarkable correspondence exists between the cytogenetic locations of the known fragile sites and frequently reported sites of hypermethylation. The best-known features of fragile sites are sequence motifs that are prone to the spontaneous formation of a non-B DNA structure. These facts, coupled with the known enzymological specificities of DNA methyltransferase 1 (DNMT1), the ATP-dependent and actin-dependent helicases, and the ten-eleven translocation (TET) dioxygenases, suggest that these enzymes are involved in an epigenetic cycle that maintains the unmethylated state at these sites by resolving non-B structure, preventing both the sequestration of DNA methyltransferases (DNMTs) and hypermethylation in normal cells. Presentation of the hypothesis The innate tendency of DNA sequences present at fragile sites to form non-B DNA structures results in de novo methylation of DNA at these sites that is held in check in normal cells by the action of ATP-dependent and actin-dependent helicases coupled with the action of TET dioxygenases. This constitutes a previously unrecognized epigenetic repair cycle in which spontaneously forming non-B DNA structures formed at fragile sites are methylated by DNMTs as they are removed by the action of ATP-dependent and actin-dependent helicases, with the resulting nascent methylation rendered non-transmissible by TET dioxygenases. Testing the hypothesis A strong prediction of the hypothesis is that knockdown of ATP-dependent and actin-dependent helicases will result in enhanced bisulfite sensitivity and hypermethylation at non-B structures in multiple fragile sites coupled with global hypomethylation. Implications of the hypothesis A key implication of the hypothesis is that helicases, like the lymphoid-specific helicase and alpha thalassemia/mental retardation syndrome X-linked helicase, passively promote accurate maintenance of DNA methylation by preventing the sequestration of DNMTs at sites of unrepaired non-B DNA

  19. Origin of Cardiac Fibroblasts and the Role of Periostin

    PubMed Central

    Snider, Paige; Standley, Kara N.; Wang, Jian; Azhar, Mohamad; Doetschman, Thomas; Conway, Simon J.

    2009-01-01

    Cardiac fibroblasts are the most populous non-myocyte cell type within the mature heart and are required for extracellular matrix synthesis and deposition, generation of the cardiac skeleton, and to electrically insulate the atria from the ventricles. Significantly, cardiac fibroblasts have also been shown to play an important role in cardiomyocyte growth and expansion of the ventricular chambers during heart development. Although there are currently no cardiac fibroblast-restricted molecular markers, it is generally envisaged that the majority of the cardiac fibroblasts are derived from the proepicardium via epithelial-to-mesenchymal transformation. However, still relatively little is known about when and where the cardiac fibroblasts cells are generated, the lineage of each cell, and how cardiac fibroblasts move to reside in their final position throughout all four cardiac chambers. In this review we summarize the current understanding regarding the function of Periostin, a useful marker of the non-cardiomyocyte lineages, and its role during cardiac morphogenesis. Characterization of the cardiac fibroblast lineage and identification of the signals that maintain, expand and regulate their differentiation will be required to improve our understanding of cardiac function in both normal and pathophysiological states. PMID:19893021

  20. 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 ...

  1. Modified bonded bridge space maintainer.

    PubMed

    Liegeois, F; Limme, M

    1999-01-01

    The premature loss of primary teeth can create the need for space maintenance and restoration of function. This article presents a fixed bonded space maintainer, which allows space to be maintained with economy of dental tissues.

  2. High-output heart failure in a newborn

    PubMed Central

    Mascarenhas, Maria Inês; Moniz, Marta; Ferreira, Sofia; Goulão, Augusto; Barroso, Rosalina

    2012-01-01

    High-output cardiac failure is rare in newborns. Emergent diagnosis and management of this pathology is crucial. We report the case of a child, currently 12-months old; obstetric background is non-contributory. Clinic observation on D1 was normal except for the presence of a systolic cardiac murmur; cardiological evaluation revealed mild ventricular dysfunction of the right ventricle. On the third day of life, she developed cardiac failure with gallop rhythm, hepatomegaly and a murmur in the anterior fontanel; an echocardiogram confirmed clinic aggravation with biventricular dysfunction and right cavities and superior vena cava dilatation. The cranial MRI confirmed the presence of a pial arteriovenous malformation (AVM) involving the anterior and middle cerebral arteries with an associated fronto-parietal ischaemic lesion. The infant underwent embolisations of AVM with successful flow reduction and cardiac failure improvement. The multidisciplinary follow-up showed no cardiac dysfunction or permanent lesions but confirmed a severe psycho-motor delay and left hemiparesia. PMID:22783011

  3. High-output heart failure in a newborn.

    PubMed

    Mascarenhas, Maria Inês; Moniz, Marta; Ferreira, Sofia; Goulão, Augusto; Barroso, Rosalina

    2012-01-01

    High-output cardiac failure is rare in newborns. Emergent diagnosis and management of this pathology is crucial. We report the case of a child, currently 12-months old; obstetric background is non-contributory. Clinic observation on D1 was normal except for the presence of a systolic cardiac murmur; cardiological evaluation revealed mild ventricular dysfunction of the right ventricle. On the third day of life, she developed cardiac failure with gallop rhythm, hepatomegaly and a murmur in the anterior fontanel; an echocardiogram confirmed clinic aggravation with biventricular dysfunction and right cavities and superior vena cava dilatation. The cranial MRI confirmed the presence of a pial arteriovenous malformation (AVM) involving the anterior and middle cerebral arteries with an associated fronto-parietal ischaemic lesion. The infant underwent embolisations of AVM with successful flow reduction and cardiac failure improvement. The multidisciplinary follow-up showed no cardiac dysfunction or permanent lesions but confirmed a severe psycho-motor delay and left hemiparesia. PMID:22783011

  4. Role of NRSF/REST in the regulation of cardiac gene expression and function.

    PubMed

    Kuwahara, Koichiro

    2013-01-01

    Alterations in the cardiac gene program affect both cardiac structure and function, and play a key role in the progression of pathological cardiac remodeling and heart failure. For instance, reactivation of fetal cardiac genes in adults is a consistent feature of cardiac hypertrophy and heart failure. Investigation of the transcriptional regulation of cardiac genes revealed a transcriptional repressor, neuron-restrictive silencer factor (NRSF), also called repressor element-1 silencing factor (REST), to be an important regulator of multiple fetal cardiac genes. Inhibition of NRSF in the heart leads to cardiac dysfunction and sudden arrhythmic death accompanied by re-expression of various fetal genes, including those encoding fetal ion channels, such as the HCN channels and T-type Ca(2+) channels. These findings shed light on the crucial regulatory function of NRSF in the heart and its importance for maintaining normal cardiac integrity. PMID:24126098

  5. Cardiac ion channels

    PubMed Central

    Priest, Birgit T; McDermott, Jeff S

    2015-01-01

    Ion channels are critical for all aspects of cardiac function, including rhythmicity and contractility. Consequently, ion channels are key targets for therapeutics aimed at cardiac pathophysiologies such as atrial fibrillation or angina. At the same time, off-target interactions of drugs with cardiac ion channels can be the cause of unwanted side effects. This manuscript aims to review the physiology and pharmacology of key cardiac ion channels. The intent is to highlight recent developments for therapeutic development, as well as elucidate potential mechanisms for drug-induced cardiac side effects, rather than present an in-depth review of each channel subtype. PMID:26556552

  6. Mapping of cardiac electrophysiology onto a dynamic patient-specific heart model.

    PubMed

    Wilson, Kevin; Guiraudon, Gerard; Jones, Douglas L; Peters, Terry M

    2009-12-01

    Electrophysiological cardiac data mapping is an essential tool for the study of cardiac rhythm disorders, such as atrial fibrillation. Over the past decade, various advanced cardiac mapping systems have been developed to create detailed cardiac maps and assist physicians in diagnosis and therapy guidance. While these systems have increased the ability to study and treat cardiac arrhythmias, inherent limitations exist. The objective of this paper is to describe and evaluate a system that extends current approaches to cardiac mapping, to create a dynamic cardiac map, using patient-specific cardiac models. This paper details novel approaches to collecting a stream of electrophysiological cardiac data, registering the data with patient-specific dynamic cardiac models, and displaying the data directly on the dynamic model surface, giving a more accurate and comprehensive visualization environment when compared to current systems. To validate the system, a series of laboratory and in vivo experiments were conducted. In the laboratory studies, the system was used to test the user's ability to accurately locate a landmark in physical space, as well as their ability to accurately navigate to a virtual location. In the in vivo studies the overall system performance was compared to an existing electrophysiological recording system, where right atrial cardiac maps were created during sinus and paced cardiac rhythms. The results showed that the new dynamic cardiac mapping system was able to maintain high accuracy in locating physical and virtual landmarks, while being able to create a dynamic cardiac map displayed on a dynamic cardiac surface model. PMID:19423433

  7. 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.

  8. 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

  9. Body size and work output.

    PubMed

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

    1977-03-01

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

  10. 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.

  11. CMOS output buffer wave shaper

    NASA Technical Reports Server (NTRS)

    Albertson, L.; Whitaker, S.; Merrell, R.

    1990-01-01

    As the switching speeds and densities of Digital CMOS integrated circuits continue to increase, output switching noise becomes more of a problem. A design technique which aids in the reduction of switching noise is reported. The output driver stage is analyzed through the use of an equivalent RLC circuit. The results of the analysis are used in the design of an output driver stage. A test circuit based on these techniques is being submitted to MOSIS for fabrication.

  12. Nonlinear input-output systems

    NASA Technical Reports Server (NTRS)

    Hunt, L. R.; Luksic, Mladen; Su, Renjeng

    1987-01-01

    Necessary and sufficient conditions that the nonlinear system dot-x = f(x) + ug(x) and y = h(x) be locally feedback equivalent to the controllable linear system dot-xi = A xi + bv and y = C xi having linear output are found. Only the single input and single output case is considered, however, the results generalize to multi-input and multi-output systems.

  13. Exploring cardiac biophysical properties

    PubMed Central

    Mou, Younss Ait; Bollensdorff, Christian; Cazorla, Olivier; Magdi, Yacoub; de Tombe, Pieter P.

    2015-01-01

    The heart is subject to multiple sources of stress. To maintain its normal function, and successfully overcome these stresses, heart muscle is equipped with fine-tuned regulatory mechanisms. Some of these mechanisms are inherent within the myocardium itself and are known as intrinsic mechanisms. Over a century ago, Otto Frank and Ernest Starling described an intrinsic mechanism by which the heart, even ex vivo, regulates its function on a beat-to-beat basis. According to this phenomenon, the higher the ventricular filling is, the bigger the stroke volume. Thus, the Frank-Starling law establishes a direct relationship between the diastolic and systolic function of the heart. To observe this biophysical phenomenon and to investigate it, technologic development has been a pre-requisite to scientific knowledge. It allowed for example to observe, at the cellular level, a Frank-Starling like mechanism and has been termed: Length Dependent Activation (LDA). In this review, we summarize some experimental systems that have been developed and are currently still in use to investigate cardiac biophysical properties from the whole heart down to the single myofibril. As a scientific support, investigation of the Frank-Starling mechanism will be used as a case study. PMID:26779498

  14. Neurons within the same network independently achieve conserved output by differentially balancing variable conductance magnitudes.

    PubMed

    Ransdell, Joseph L; Nair, Satish S; Schulz, David J

    2013-06-12

    Biological and theoretical evidence suggest that individual neurons may achieve similar outputs by differentially balancing variable underlying ionic conductances. Despite the substantial amount of data consistent with this idea, a direct biological demonstration that cells with conserved output, particularly within the same network, achieve these outputs via different solutions has been difficult to achieve. Here we demonstrate definitively that neurons from native neural networks with highly similar output achieve this conserved output by differentially tuning underlying conductance magnitudes. Multiple motor neurons of the crab (Cancer borealis) cardiac ganglion have highly conserved output within a preparation, despite showing a 2-4-fold range of conductance magnitudes. By blocking subsets of these currents, we demonstrate that the remaining conductances become unbalanced, causing disparate output as a result. Therefore, as strategies to understand neuronal excitability become increasingly sophisticated, it is important that such variability in excitability of neurons, even among those within the same individual, is taken into account. PMID:23761890

  15. 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.

  16. 4 CFR 200.14 - Responsibility for maintaining adequate safeguards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... identifiable personal data and automated systems shall be adequately trained in the security and privacy of... records in which identifiable personal data are processed or maintained, including all reports and output... personal records or data; must minimize, to the extent practicable, the risk that skilled technicians...

  17. Intensive Hemodialysis Preserved Cardiac injury.

    PubMed

    Chan, Christopher T; Li, Guo Hua; Valaperti, Alan; Liu, Peter

    2015-01-01

    Cardiac injury triggers cellular responses involving both cardiomyocytes and nonmuscle cells to process cardiac structural remodeling. End-stage renal disease (ESRD), despite conventional dialysis, is associated with adverse cardiac remodeling and increased cardiovascular events. Intensification of hemodialysis with nocturnal home hemodialysis (NHD; five sessions per week; 6-8 hours per treatment) was associated with regression of left ventricular hypertrophy and downregulation of genes in apoptosis and fibrosis. In this pilot study, we hypothesize that NHD achieves its cardiac effects in part through attenuation of innate immune activation resulting in amelioration of cardiomyocytes apoptosis and fibrosis. Eight patients (4M:4F; age, 59 ± 9 years) with ESRD were studied. Half of the cohort was converted to NHD, whereas the rest of the patients were maintained on conventional hemodialysis (CHD). At baseline, CHD was associated with an increase in cardiomyocyte apoptosis detected by flow cytometry using Annexin V (mean fluorescence index in CHD and in normal control is 1.00 ± 0.05 vs. 0.66 ± 0.01, p < 0.05). After conversion to NHD, cardiomyocyte apoptosis was reduced compared with baseline CHD situation (p < 0.05) and approached that of normal control (0.59 ± 0.09 vs. 0.66 ± 0.01, p > 0.05). The CHD serum was associated with a coordinated augmentation innate immunity pathway, significantly increasing myeloid differentiation factor-88 and interleukin-1 receptor-associated kinase-4; NHD was able to reduce their levels. Heat shock protein 60 was augmented during CHD condition and fell after NHD. In addition, CHD increased fibroblast proliferation and myofibroblast transformation. Uremia is associated with activation of common innate immune signaling pathways leading to fibrosis and apoptosis. Amelioration of uremic clearance by NHD may attenuate this pathological signaling cascade. PMID:26164598

  18. 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.

  19. 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

  20. [Cardiac rehabilitation after coronary artery bypass surgery].

    PubMed

    Dayan, Victor; Ricca, Roberto

    2014-01-01

    Ischemic heart disease is the leading cause of death worldwide with an increase in the incidence in younger populations. Today revascularization strategies are capable of alleviating acute ischemia and/or chronic ischemia. These can be performed percutaneously or through surgery. Even if we improve myocardial perfusion by these methods, the main determinant in maintaining patency of coronary arteries and bypass is a correctly instituted secondary prevention. This is the main focus of cardiac rehabilitation proposals. Although much has been published about the role of cardiac rehabilitation after percutaneous revascularization, there is little work able to synthesize the current state of cardiac rehabilitation in patients undergoing coronary artery bypass surgery. The aim of this paper is to review the effect of rehabilitation in the return to work, survival, functional capacity, depression and anxiety, as well as compare centralized vs. home rehabilitation in this patient population.

  1. Marketing cardiac CT programs.

    PubMed

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

  2. Hypothermia improves outcome from cardiac arrest.

    PubMed

    Bernard, S A

    2005-12-01

    Out-of-hospital cardiac arrest is common and patients who are initially resuscitated by ambulance officers and transported to hospital are usually admitted to the intensive care unit (ICU). In the past, the treatment in the ICU consisted of supportive care only, and most patients remained unconscious due to the severe anoxic neurological injury. It was this neurological injury rather than cardiac complications that caused the high rate of morbidity and mortality. However, in the early 1990's, a series of animal experiments demonstrated convincingly that mild hypothermia induced after return of spontaneous circulation and maintained for several hours dramatically reduced the severity of the anoxic neurological injury. In the mid-1990's, preliminary human studies suggested that mild hypothermia could be induced and maintained in post-cardiac arrest patients without an increase in the rate of cardiac or other complications. In the late 1990's, two prospective, randomised, controlled trials were conducted and the results confirmed the animal data that mild hypothermia induced after resuscitation and maintained for 12 - 24 hours dramatically improved neurological and overall outcomes. On the basis of these studies, mild hypothermia was endorsed in 2003 by the International Liaison Committee on Resuscitation as a recommended treatment for comatose patients with an initial cardiac rhythm of ventricular fibrillation. However, the application of this therapy into routine clinical critical care practice has been slow. The reasons for this are uncertain, but may relate to the relative complexity of the treatment, unfamiliarity with the pathophysiology of hypothermia, lack of clear protocols and/or uncertainty of benefit in particular patients. Therefore, recent research in this area has focused on the development of feasible, inexpensive techniques for the early, rapid induction of mild hypothermia after cardiac arrest. Currently, the most promising strategy is a rapid

  3. 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

  4. Cardiac Function at Rest and During Exercise in Normals and in Patients with Coronary Heart Disease: Evaluation by Radionuclide Angiocardiography

    PubMed Central

    Rerych, Stephen K.; Scholz, Peter M.; Newman, Glenn E.; Sabiston, David C.; Jones, Robert H.

    1978-01-01

    This study demonstrates that radionuclide angiocardiography provides a simple and noninvasive approach for evaluation of myocardial function. Previous work concerning myocardial performance has been generally conducted with the patient in the supine position. Radionuclide angiocardiograms were performed in the present study at rest and during exercise in 30 normal subjects and in 30 patients with ischemic coronary artery disease. There were 30 normal controls (Group I), ten with single coronary artery disease (Group II), and 20 patients with multiple vessel coronary disease (Group III). All subjects were studied in the erect posture on a bicycle ergometer. In the normal controls, the mean heart rate doubled and the cardiac output tripled during exercise. Intensive training can lead to extraordinary levels of cardiac performance as shown in a world-class athlete who during peak exercise attained a heart rate of 210, an ejection fraction of 97%, and a cardiac output of 56 litres per minute. In the patients with coronary artery disease, both groups, were able to increase cardiac output to approximately twice the resting value. The magnitude of increase in blood pressure during exercise was not significantly different in the three groups. However, definite changes were present in the end-diastolic volume at rest was 116 and rose to 128 ml in Group I, 93 rising to 132 ml in Group II, and 138 increasing to 216 ml in Group III. The stroke volume increased comparably in all three groups, but the ejection fraction from rest to exercise showed a marked contrast in the controls compared to those with multivessel coronary disease. The ejection fraction rose in Group I from 66 to 80% during exercise, while in Group II it fell from 69 to 67%, and in Group III from 60 to 46%. These findings indicate that patients with ischemic myocardial disease respond to the stress of exercise by cardiac dilatation to maintain of increase stroke volume at increased heart rates. Moreover, the

  5. 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.

  6. 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.

  7. 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

  8. Simple fixed functional space maintainer.

    PubMed

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

    2014-01-01

    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.

  9. Cardiac Physiology of Aging: Extracellular Considerations.

    PubMed

    Horn, Margaux A

    2015-07-01

    Aging is a major risk factor for the development of cardiovascular disease, with the majority of affected patients being elderly. Progressive changes to myocardial structure and function occur with aging, often in concert with underlying pathologies. However, whether chronological aging results in a remodeled "aged substrate" has yet to be established. In addition to myocyte contractility, myocardial performance relies heavily on the cardiac extracellular matrix (ECM), the roles of which are as dynamic as they are significant; including providing structural integrity, assisting in force transmission throughout the cardiac cycle and acting as a signaling medium for communication between cells and the extracellular environment. In the healthy heart, ECM homeostasis must be maintained, and matrix deposition is in balance with degradation. Consequently, alterations to, or misregulation of the cardiac ECM has been shown to occur in both aging and in pathological remodeling with disease. Mounting evidence suggests that age-induced matrix remodeling may occur at the level of ECM control; including collagen synthesis, deposition, maturation, and degradation. Furthermore, experimental studies using aged animal models not only suggest that the aged heart may respond differently to insult than the young, but the identification of key players specific to remodeling with age may hold future therapeutic potential for the treatment of cardiac dysfunction in the elderly. This review will focus on the role of the cardiac interstitium in the physiology of the aging myocardium, with particular emphasis on the implications to age-related remodeling in disease.

  10. Measuring Air-Ionizer Output

    NASA Technical Reports Server (NTRS)

    Lonborg, J. O.

    1985-01-01

    Test apparatus checks ion content of airstream from commercial air ionizer. Apparatus ensures ion output is sufficient to neutralize static charges in electronic assembly areas and concentrations of positive and negative ions are balanced.

  11. 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.

  12. 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.

  13. Cardiac pathological conditions in young soldiers: case series.

    PubMed

    Villacorta-Lyew, Rachel; Laselle, Brooks; Mazzoncini, Joseph P; Merchant, Emily; Buckley, Peter J

    2008-11-01

    We briefly review the disease processes for four young healthy soldiers who presented to our emergency department with serious cardiac pathological conditions. We present two unusual cases of myocardial infarction, a coronary artery aneurysm, and a case of smallpox vaccine-induced myocarditis/pericarditis. Our intent is to encourage others in military medicine to maintain a high index of suspicion for cardiac conditions even in a relatively young healthy population. PMID:19055189

  14. Action of SNAIL1 in Cardiac Myofibroblasts Is Important for Cardiac Fibrosis following Hypoxic Injury

    PubMed Central

    Biswas, Hirak; Longmore, Gregory D.

    2016-01-01

    Hypoxic injury to the heart results in cardiac fibrosis that leads to cardiac dysfunction and heart failure. SNAIL1 is a zinc finger transcription factor implicated in fibrosis following organ injury and cancer. To determine if the action of SNAIL1 contributed to cardiac fibrosis following hypoxic injury, we used an endogenous SNAIL1 bioluminescence reporter mice, and SNAIL1 knockout mouse models. Here we report that SNAIL1 expression is upregulated in the infarcted heart, especially in the myofibroblasts. Utilizing primary cardiac fibroblasts in ex vivo cultures we find that pro-fibrotic factors and collagen I increase SNAIL1 protein level. SNAIL1 is required in cardiac fibroblasts for the adoption of myofibroblast fate, collagen I expression and expression of fibrosis-related genes. Taken together this data suggests that SNAIL1 expression is induced in the cardiac fibroblasts after hypoxic injury and contributes to myofibroblast phenotype and a fibrotic scar formation. Resultant collagen deposition in the scar can maintain elevated SNAIL1 expression in the myofibroblasts and help propagate fibrosis. PMID:27706205

  15. Measurement of cardiac troponins.

    PubMed

    Collinson, P O; Boa, F G; Gaze, D C

    2001-09-01

    The cardiac troponins form part of the regulatory mechanism for muscle contraction. Specific cardiac isoforms of cardiac troponin T and cardiac troponin I exist and commercially available immunoassay systems have been developed for their measurement. A large number of clinical and analytical studies have been performed and the measurement of cardiac troponins is now considered the 'gold standard' biochemical test for diagnosis of myocardial damage. There have been advances in understanding the development and structure of troponins and their degradation following myocardial cell necrosis. This has contributed to the understanding of the problems with current assays. Greater clinical use has also highlighted areas of analytical and clinical confusion. The assays are reviewed based on manufacturers' information, current published material as well as the authors' in-house experience.

  16. Functional cardiac tissue engineering

    PubMed Central

    Liau, Brian; Zhang, Donghui; Bursac, Nenad

    2013-01-01

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

  17. Cardiac Hegemony of Senescence

    PubMed Central

    Siddiqi, Sailay; Sussman, Mark A.

    2013-01-01

    Cardiac senescence and age-related disease development have gained general attention and recognition in the past decades due to increased accessibility and quality of health care. The advancement in global civilization is complementary to concerns regarding population aging and development of chronic degenerative diseases. Cardiac degeneration has been rigorously studied. The molecular mechanisms of cardiac senescence are on multiple cellular levels and hold a multilayer complexity level, thereby hampering development of unambiguous treatment protocols. In particular, the synergistic exchange of the senescence phenotype through a senescence secretome between myocytes and stem cells appears complicated and is of great future therapeutic value. The current review article will highlight hallmarks of senescence, cardiac myocyte and stem cell senescence, and the mutual exchange of senescent secretome. Future cardiac cell therapy approaches require a comprehensive understanding of myocardial senescence to improve therapeutic efficiency as well as efficacy. PMID:24349878

  18. [Assessment and evaluation of cardiac function].

    PubMed

    Yazaki, Y

    1993-05-01

    Assessment and evaluation of cardiac function have become commonplace in the care of cardiac patients with acute or chronic disorders, since therapy of most cardiac diseases is designed specifically to improve ventricular function. Now, various techniques are available for quantitative measurements of the size, shape and motion of the ventricle. Ventricular dysfunction is defined with two components, systolic and diastolic dysfunction, and can be described hemodynamically in terms of the ventricular pressure-volume diagram. Pure systolic dysfunction is associated with a depression in the end-systolic pressure-volume relation, using the Frank-Starling relation to restore cardiac output toward normal. In contrast, pure diastolic dysfunction is associated with preservation of the end-systolic pressure-volume relation but distortion of the diastolic relation, showing higher diastolic pressure at any given volume. However, in patients presenting clinically with heart failure, both systolic and diastolic dysfunction are usually observed. In this context, factors and disorders that influence ventricular dysfunction are described, considering extrinsic or intrinsic to the ventricular chambers.

  19. Ultrasound imaging in teaching cardiac physiology.

    PubMed

    Johnson, Christopher D; Montgomery, Laura E A; Quinn, Joe G; Roe, Sean M; Stewart, Michael T; Tansey, Etain A

    2016-09-01

    This laboratory session provides hands-on experience for students to visualize the beating human heart with ultrasound imaging. Simple views are obtained from which students can directly measure important cardiac dimensions in systole and diastole. This allows students to derive, from first principles, important measures of cardiac function, such as stroke volume, ejection fraction, and cardiac output. By repeating the measurements from a subject after a brief exercise period, an increase in stroke volume and ejection fraction are easily demonstrable, potentially with or without an increase in left ventricular end-diastolic volume (which indicates preload). Thus, factors that affect cardiac performance can readily be discussed. This activity may be performed as a practical demonstration and visualized using an overhead projector or networked computers, concentrating on using the ultrasound images to teach basic physiological principles. This has proved to be highly popular with students, who reported a significant improvement in their understanding of Frank-Starling's law of the heart with ultrasound imaging. PMID:27445285

  20. 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.

  1. Query cardiac pain.

    PubMed

    Todd, J W

    1983-08-01

    Query cardiac pain is a common problem, and immense efforts are made to solve it. No test can prove that a patient has not had a cardiac infarct, though in the recent past eminent authorities wrongly stated that a normal ECG supplied this proof. This history is by far the most important means of interpreting recurrent pain. Coronary arteriography is only useful in diagnosis when the pain is certainly due to myocardial ischaemia but it is uncertain whether this is caused by coronary artery disease or some other cardiac lesion. In practice, much pain is not diagnosed. This need be no cause for concern, and patients who in fact have had a small cardiac infarct gain rather than lose if wrongly reassured of its non-existence. The history of cardiology is a depressing catalogue of error. Bogus cardiac diseases have been diagnosed on an enormous scale, mainly because attention has been concentrated on the cardiac manifestations, while the patient was ignored. Much "excluding" is fatuous. Because treatment was derived from theory, treatment for patients who had had cardiac infarcts was disastrous. The great error at present is to overvalue technology.

  2. 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

  3. 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.

  4. 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.

  5. [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

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

    PubMed Central

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

    2015-01-01

    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 Ca2+ was increased in isolated Rad−/− ventricular myocytes. Higher Ca2+ load was accompanied by sarco/endoplasmic reticulum Ca2+ 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

  7. 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

  8. 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…

  9. 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.

  10. Maintaining Discipline in Classroom Instruction.

    ERIC Educational Resources Information Center

    Gnagey, William J.

    This document focuses on classroom discipline and how the teacher can maintain an environment that will optimize appropriate learning. Part 1 defines classroom discipline. Part 2 discusses classroom misbehavior and describes a number of classroom management techniques. Part 3 offers suggestions for control techniques. Part 4 discusses techniques…

  11. Molecular Basis of Cardiac Myxomas

    PubMed Central

    Singhal, Pooja; Luk, Adriana; Rao, Vivek; Butany, Jagdish

    2014-01-01

    Cardiac tumors are rare, and of these, primary cardiac tumors are even rarer. Metastatic cardiac tumors are about 100 times more common than the primary tumors. About 90% of primary cardiac tumors are benign, and of these the most common are cardiac myxomas. Approximately 12% of primary cardiac tumors are completely asymptomatic while others present with one or more signs and symptoms of the classical triad of hemodynamic changes due to intracardiac obstruction, embolism and nonspecific constitutional symptoms. Echocardiography is highly sensitive and specific in detecting cardiac tumors. Other helpful investigations are chest X-rays, magnetic resonance imaging and computerized tomography scan. Surgical excision is the treatment of choice for primary cardiac tumors and is usually associated with a good prognosis. This review article will focus on the general features of benign cardiac tumors with an emphasis on cardiac myxomas and their molecular basis. PMID:24447924

  12. 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

  13. The output from human inspiratory motoneurone pools

    PubMed Central

    Butler, Jane E; Gandevia, Simon C

    2008-01-01

    Survival requires adequate pulmonary ventilation which, in turn, depends on adequate contraction of muscles acting on the chest wall in the presence of a patent upper airway. Bulbospinal outputs projecting directly and indirectly to ‘obligatory’ respiratory motoneurone pools generate the required muscle contractions. Recent studies of the phasic inspiratory output of populations of single motor units to five muscles acting on the chest wall (including the diaphragm) reveal that the time of onset, the progressive recruitment, and the amount of motoneuronal drive (expressed as firing frequency) differ among the muscles. Tonic firing with an inspiratory modulation of firing rate is common in low intercostal spaces of the parasternal and external intercostal muscles but rare in the diaphragm. A new time and frequency plot has been developed to depict the behaviour of the motoneurone populations. The magnitude of inspiratory firing of motor unit populations is linearly correlated to the mechanical advantage of the intercostal muscle region at which the motor unit activity is recorded. This represents a ‘neuromechanical’ principle by which the CNS controls motoneuronal output according to mechanical advantage, presumably in addition to the Henneman's size principle of motoneurone recruitment. Studies of the genioglossus, an obligatory upper airway muscle that helps maintain airway patency, reveal that it receives simultaneous inspiratory, expiratory and tonic drives even during quiet breathing. There is much to be learned about the neural drive to pools of human inspiratory and expiratory muscles, not only during respiratory tasks but also in automatic and volitional tasks, and in diseases that alter the required drive. PMID:17974589

  14. Cardiac glycoside overdose

    MedlinePlus

    ... found in the leaves of the digitalis (foxglove) plant. This plant is the original source of this medicine. People ... Digitoxin (Crystodigin) Digoxin (Lanoxicaps, Lanoxin) Besides the foxglove plant, cardiac glycosides also occur naturally in plants such ...

  15. 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

  16. 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) ...

  17. Neuroprotection during cardiac surgery.

    PubMed

    Grocott, Hilary P; Yoshitani, Kenji

    2007-01-01

    Cerebral injury following cardiac surgery continues to be a significant source of morbidity and mortality after cardiac surgery. A spectrum of injuries ranging from subtle neurocognitive dysfunction to fatal strokes are caused by a complex series of multifactorial mechanisms. Protecting the brain from these injuries has focused on intervening on each of the various etiologic factors. Although numerous studies have focused on a pharmacologic solution, more success has been found with nonpharmacologic strategies, including optimal temperature management and reducing emboli generation. PMID:17680190

  18. Ranolazine in Cardiac Arrhythmia.

    PubMed

    Saad, Marwan; Mahmoud, Ahmed; Elgendy, Islam Y; Richard Conti, C

    2016-03-01

    Ranolazine utilization in the management of refractory angina has been established by multiple randomized clinical studies. However, there is growing evidence showing an evolving role in the field of cardiac arrhythmias. Multiple experimental and clinical studies have evaluated the role of ranolazine in prevention and management of atrial fibrillation, with ongoing studies on its role in ventricular arrhythmias. In this review, we will discuss the pharmacological, experimental, and clinical evidence behind ranolazine use in the management of various cardiac arrhythmias.

  19. Cardiac rehabilitation in Germany.

    PubMed

    Karoff, Marthin; Held, Klaus; Bjarnason-Wehrens, Birna

    2007-02-01

    The purpose of this review is to give an overview of the rehabilitation measures provided for cardiac patients in Germany and to outline its legal basis and outcomes. In Germany the cardiac rehabilitation system is different from rehabilitation measures in other European countries. Cardiac rehabilitation in Germany since 1885 is based on specific laws and the regulations of insurance providers. Cardiac rehabilitation has predominantly been offered as an inpatient service, but has recently been complemented by outpatient services. A general agreement on the different indications for offering these two services has yet to be reached. Cardiac rehabilitation is mainly offered after an acute cardiac event and bypass surgery. It is also indicated in severe heart failure and special cases of percutaneous coronary intervention. Most patients are men (>65%) and the age at which events occur is increasing. The benefits obtained during the 3-4 weeks after an acute event, and confirmed in numerous studies, are often later lost under 'usual care' conditions. Many attempts have been made by rehabilitation institutions to improve this deficit by providing intensive aftercare. One instrument set up to achieve this is the nationwide institution currently comprising more than 6000 heart groups with approximately 120000 outpatients. After coronary artery bypass grafting or acute coronary syndrome cardiac rehabilitation can usually be started within 10 days. The multidisciplinary rehabilitation team consists of cardiologists, psychologists, exercise therapists, social workers, nutritionists and nurses. The positive effects of cardiac rehabilitation are also important economically, for example, for the improvement of secondary prevention and vocational integration. PMID:17301623

  20. Ranolazine in Cardiac Arrhythmia.

    PubMed

    Saad, Marwan; Mahmoud, Ahmed; Elgendy, Islam Y; Richard Conti, C

    2016-03-01

    Ranolazine utilization in the management of refractory angina has been established by multiple randomized clinical studies. However, there is growing evidence showing an evolving role in the field of cardiac arrhythmias. Multiple experimental and clinical studies have evaluated the role of ranolazine in prevention and management of atrial fibrillation, with ongoing studies on its role in ventricular arrhythmias. In this review, we will discuss the pharmacological, experimental, and clinical evidence behind ranolazine use in the management of various cardiac arrhythmias. PMID:26459200

  1. Cardiac Munchausen's syndrome.

    PubMed Central

    Dickinson, E J; Evans, T R

    1987-01-01

    Ten years' experience of cardiac Munchausen's syndrome in the Cardiac Care Unit of an Inner London teaching hospital is reported. Thirty-six admissions in this category were identified and analysed, and 4 typical cases are described. The common presenting complaints, recurring features and the relationship with other forms of Munchausen's syndrome are discussed, as are possible strategies available to deal with this clinical entity. PMID:3694601

  2. 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.

  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. Compact Circuit Preprocesses Accelerometer Output

    NASA Technical Reports Server (NTRS)

    Bozeman, Richard J., Jr.

    1993-01-01

    Compact electronic circuit transfers dc power to, and preprocesses ac output of, accelerometer and associated preamplifier. Incorporated into accelerometer case during initial fabrication or retrofit onto commercial accelerometer. Made of commercial integrated circuits and other conventional components; made smaller by use of micrologic and surface-mount technology.

  5. 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

  6. Input/output interface module

    NASA Technical Reports Server (NTRS)

    Ozyazici, E. M.

    1980-01-01

    Module detects level changes in any of its 16 inputs, transfers changes to its outputs, and generates interrupts when changes are detected. Up to four changes-in-state per line are stored for later retrieval by controlling computer. Using standard TTL logic, module fits 19-inch rack-mounted console.

  7. 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…

  8. 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.

  9. Cardiac Applications of Optogenetics

    PubMed Central

    Ambrosi, Christina M.; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-01-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics. PMID:25035999

  10. Trends in cardiac metastasis.

    PubMed

    Karwinski, B; Svendsen, E

    1989-11-01

    A review of 8571 autopsies disclosed 2833 patients with malignant tumours from 1975 to 1984 at the Department of Pathology, The Gade Institute. Cardiac metastases were found in 130 cases. An increase of cardiac involvement was shown in the autopsy material from 1.2% in 1975-1979 to 1.8% in 1980-1984. The same trend was seen if cardiac metastases were related to malignant tumours. Numerically, lung cancer accounted for most of the metastases seen, but the increase was made up by other tumours than lung cancer. especially malignant melanoma, mesothelioma, breast cancer and sarcomas. These tumours have a high frequency of heart metastases and the increased incidence of these cancers in the material explains the rise of cardiac metastases. Cardiac metastases increased with rising number of distant metastases. This study shows that mesotheliomas have the highest percentage of cardiac spread. The importance of autopsy for detecting metastatic spread in sites that are difficult to detect clinically is emphasized.

  11. Cardiac applications of optogenetics.

    PubMed

    Ambrosi, Christina M; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-08-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics.

  12. Repeated pericardiocentesis as palliative treatment for tamponade associated with cardiac lymphoma in a Holstein cow

    PubMed Central

    Buczinski, Sébastien; Boulay, Guillaume; DesCôteaux, Luc

    2011-01-01

    Maintaining a good quality of life for cows with cardiac manifestation of lymphoma may be valuable, especially in high-producing cows. This report describes the medical management of cardiac lymphoma in a cow by means of repeated pericardiocentesis. The cow survived for 34 days and was productive. PMID:22131585

  13. 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.

  14. 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

  15. Comparison of Albumin, Hydroxyethyl Starch and Ringer Lactate Solution as Priming Fluid for Cardiopulmonary Bypass in Paediatric Cardiac Surgery

    PubMed Central

    Prajapati, Mrugesh; Solanki, Atul; Pandya, Himani

    2016-01-01

    Introduction In paediatric cardiac surgery, there is still not any information with regard to the best choice of priming fluids for Cardiopulmonary Bypass (CPB). Albumin, Hydroxyethyl Starch (HES) & ringer lactate are equally used, but each has its advantages & disadvantages. Albumin & HES had better fluid balance which affect outcome in paediatric cardiac surgery significantly. Aim To compare priming solution containing albumin, hydroxyethyl starch and ringer lactate during elective open-heart surgery in paediatrics aged up to 3 years. Materials and Methods All patients were managed by standardized institution protocol and were randomly distributed into three groups based on the priming solution which is used in the CPB Circuit and having 35 patients in each group. Group A: Receive albumin 10 ml/kg in priming solution, Group B: Receive Hydroxyethyl starch (HES130/0.4) 6% 20ml/kg in priming solution, Group C: Receive ringer lactate priming solution. Primary outcome variable included perioperative haemoglobin, total protein, colloid osmotic pressure, platelets, fluid balance, urine output, post-operative blood loss, blood products usage, renal & liver function, extubation time, ICU stay & outcome. Results Patients receiving albumin had higher perioperative platelet count, total protein level & colloid osmotic pressure, lesser post-operative blood loss & blood products requirement. Patients receiving HES had lower level of platelets postoperatively than ringer lactate group but not associated with increase blood loss. HES did not affect renal function & haemostasis in this dose. Patients receiving ringer lactate had positive fluid balance intraoperatively. All three groups have similar effect on renal & liver function, urine output, time to extubation, ICU stay & outcome. Conclusion We conclude that albumin is expensive but better prime as maintain haemostasis, colloid oncotic pressure & reduced blood product requirement. HES will not hamper haemostasis & renal

  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. Anisotropic Silk Biomaterials Containing Cardiac Extracellular Matrix for Cardiac Tissue Engineering

    PubMed Central

    Stoppel, Whitney L.; Hu, Dongjian; Domian, Ibrahim J.; Kaplan, David L.; Black, Lauren D.

    2015-01-01

    Cardiac malformations and disease are the leading causes of death in the United States in live-born infants and adults, respectively. In both of these cases, a decrease in the number of functional cardiomyocytes often results in improper growth of heart tissue, wound healing complications, and poor tissue repair. The field of cardiac tissue engineering seeks to address these concerns by developing cardiac patches created from a variety of biomaterial scaffolds to be used in surgical repair of the heart. These scaffolds should be fully degradable biomaterial systems with tunable properties such that the materials can be altered to meet the needs of both in vitro culture (e.g., disease modeling) and in vivo application (e.g., cardiac patch). Current platforms do not utilize both structural anisotropy and proper cell-matrix contacts to promote functional cardiac phenotypes and thus there is still a need for critically sized scaffolds that mimic both the structural and adhesive properties of native tissue. To address this need, we have developed a silk-based scaffold platform containing cardiac tissue-derived extracellular matrix (cECM). These silk-cECM composite scaffolds have tunable architectures, degradation rates, and mechanical properties. Subcutaneous implantation in rats demonstrated that addition of the cECM to aligned silk scaffold led to 99% endogenous cell infiltration and promoted vascularization of a critically sized scaffold (10 mm × 5 mm × 2.5 mm) after 4 weeks in vivo. In vitro, silk-cECM scaffolds maintained the HL-1 atrial cardiomyocytes and human embryonic stem cell-derived cardiomyocytes and promoted a more functional phenotype in both cell types. This class of hybrid silk-cECM anisotropic scaffolds offers new opportunities for developing more physiologically relevant tissues for cardiac repair and disease modeling. PMID:25826196

  18. Anisotropic silk biomaterials containing cardiac extracellular matrix for cardiac tissue engineering.

    PubMed

    Stoppel, Whitney L; Hu, Dongjian; Domian, Ibrahim J; Kaplan, David L; Black, Lauren D

    2015-06-01

    Cardiac malformations and disease are the leading causes of death in the United States in live-born infants and adults, respectively. In both of these cases, a decrease in the number of functional cardiomyocytes often results in improper growth of heart tissue, wound healing complications, and poor tissue repair. The field of cardiac tissue engineering seeks to address these concerns by developing cardiac patches created from a variety of biomaterial scaffolds to be used in surgical repair of the heart. These scaffolds should be fully degradable biomaterial systems with tunable properties such that the materials can be altered to meet the needs of both in vitro culture (e.g. disease modeling) and in vivo application (e.g. cardiac patch). Current platforms do not utilize both structural anisotropy and proper cell-matrix contacts to promote functional cardiac phenotypes and thus there is still a need for critically sized scaffolds that mimic both the structural and adhesive properties of native tissue. To address this need, we have developed a silk-based scaffold platform containing cardiac tissue-derived extracellular matrix (cECM). These silk-cECM composite scaffolds have tunable architectures, degradation rates, and mechanical properties. Subcutaneous implantation in rats demonstrated that addition of the cECM to aligned silk scaffold led to 99% endogenous cell infiltration and promoted vascularization of a critically sized scaffold (10 × 5 × 2.5 mm) after 4 weeks in vivo. In vitro, silk-cECM scaffolds maintained the HL-1 atrial cardiomyocytes and human embryonic stem cell-derived cardiomyocytes and promoted a more functional phenotype in both cell types. This class of hybrid silk-cECM anisotropic scaffolds offers new opportunities for developing more physiologically relevant tissues for cardiac repair and disease modeling. PMID:25826196

  19. Impairment of cardiac function and energetics in experimental renal failure.

    PubMed Central

    Raine, A E; Seymour, A M; Roberts, A F; Radda, G K; Ledingham, J G

    1993-01-01

    Cardiac function and energetics in experimental renal failure in the rat (5/6 nephrectomy) have been investigated by means of an isolated perfused working heart preparation and an isometric Langendorff preparation using 31P nuclear magnetic resonance (31P NMR). 4 wk after nephrectomy cardiac output of isolated hearts perfused with Krebs-Henseleit buffer was significantly lower (P < 0.0001) at all levels of preload and afterload in the renal failure groups than in the pair-fed sham operated control group. In control hearts, cardiac output increased with increases in perfusate calcium from 0.73 to 5.61 mmol/liter whereas uremic hearts failed in high calcium perfusate. Collection of 31P NMR spectra from hearts of renal failure and control animals during 30 min normoxic Langendorff perfusion showed that basal phosphocreatine was reduced by 32% to 4.7 mumol/g wet wt (P < 0.01) and the phosphocreatine to ATP ratio was reduced by 32% (P < 0.01) in uremic hearts. During low flow ischemia, there was a substantial decrease in phosphocreatine in the uremic hearts and an accompanying marked increase in release of inosine into the coronary effluent (14.9 vs 6.1 microM, P < 0.01). We conclude that cardiac function is impaired in experimental renal failure, in association with abnormal cardiac energetics and increased susceptibility to ischemic damage. Disordered myocardial calcium utilization may contribute to these derangements. PMID:8254048

  20. 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

  1. [In recurrent atrial fibrillation should a sinus rhythm always try to be maintained? How?].

    PubMed

    de Sousa, J

    1999-10-01

    This paper presents the therapeutic options for recurrent paroxysmal atrial fibrillation. In the majority of patients, sinus rhythm should be maintained in order to improve cardiac function and decrease the risk of systemic embolism. Therapeutic options include serial pharmacological agents (with repeated external cardioversion) or non-pharmacological therapy: catheter or surgical ablation and atrial pacing.

  2. [Psychosomatic aspects of cardiac arrhythmias].

    PubMed

    Siepmann, Martin; Kirch, Wilhelm

    2010-07-01

    Emotional stress facilitates the occurrence of cardiac arrhythmias including sudden cardiac death. The prevalence of anxiety and depression is increased in cardiac patients as compared to the normal population. The risk of cardiovascular mortality is enhanced in patients suffering from depression. Comorbid anxiety disorders worsen the course of cardiac arrhythmias. Disturbance of neurocardiac regulation with predominance of the sympathetic tone is hypothesized to be causative for this. The emotional reaction to cardiac arrhythmias is differing to a large extent between individuals. Emotional stress may result from coping with treatment of cardiac arrhythmias. Emotional stress and cardiac arrhythmias may influence each other in the sense of a vicious circle. Somatoform cardiac arrhythmias are predominantly of psychogenic origin. Instrumental measures and frequent contacts between physicians and patients may facilitate disease chronification. The present review is dealing with the multifaceted relationships between cardiac arrhythmias and emotional stress. The underlying mechanisms and corresponding treatment modalities are discussed.

  3. 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.

  4. 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.

  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. Cardiac side population cells and Sca-1-positive cells.

    PubMed

    Nagai, Toshio; Matsuura, Katsuhisa; Komuro, Issei

    2013-01-01

    Since the resident cardiac stem/progenitor cells were discovered, their ability to maintain the architecture and functional integrity of adult heart has been broadly explored. The methods for isolation and purification of the cardiac stem cells are crucial for the precise analysis of their developmental origin and intrinsic potential as tissue stem cells. Stem cell antigen-1 (Sca-1) is one of the useful cell surface markers to purify the cardiac progenitor cells. Another purification strategy is based on the high efflux ability of the dye, which is a common feature of tissue stem cells. These dye-extruding cells have been called side population cells because they locate in the side of dye-retaining cells after fluorescent cell sorting. In this chapter, we describe the methodology for the isolation of cardiac SP cells and Sca-1 positive cells.

  7. Anxious attachment and psychological distress in cardiac rehabilitation patients.

    PubMed

    West, M; Sarah Rose, M; Brewis, C S

    1995-06-01

    This study investigated the relevance of anxious attachment to the differentiation of psychologically distressed and non-psychologically distressed cardiac patients. Attachment is a biologically based behavioral system in which proximity to a special other is sought or maintained to achieve a sense of safety and security. Anxious attachment, as the name denotes, fails to achieve the function of attachment in the sense of individuals having little or no confidence in the availability of their attachment figures. Empirically, three scales (feared loss of the attachment figure, proximity seeking and separation protest) capture the features of anxious attachment as elaborated by Bowlby. These scales were administered to 178 cardiac rehabilitation patients drawn from the cardiac rehabilitation program of the Calgary General Hospital. The results indicate that feared loss and proximity seeking differentiated psychologically distressed from non-psychologically distressed patients. The implications of this finding for the understanding of psychologically distressed cardiac patients are discussed.

  8. Cardiac rehabilitation in New Zealand-moving forward.

    PubMed

    Benatar, Jocelyne; Langdana, Fali; Doolan-Noble, Fiona; McLachlan, Andrew

    2016-01-01

    Modern guideline-based cardiac rehabilitation provides an evidence-based, cost effective and comprehensive approach to reduce re-infarction and mortality. It offers a multidisciplinary approach to support self-management, improves psychological and social functioning and adherence to recommended life-style changes and medications. The challenge is to broaden uptake of cardiac rehabilitation, increase participation in supervised exercise programs and ensure that healthy behaviours are maintained in the long term. Shared care planning between cardiac rehabilitation specialists and primary health providers could improve long-term adherence by ensuring continuity of care of patients who have completed a Phase 2 cardiac rehabilitation program, either facility or home based. PMID:27355170

  9. [Cardiac rehabilitation in Germany: a successful model with promising prospects].

    PubMed

    Korsukéwitz, C; Falk, J; Lindow, B

    2012-02-01

    Over the past 20 years the German Pension Insurance has rehabilitated nearly 800,000 patients with coronary heart disease. In particular, phase-II rehabilitation has been established as an integral part of cardiac patient care. However, the decreasing number of participants in phase-III must be seen critically. Today's cardiac rehabilitation is characterised by evidence-based treatment modules and a sophisticated quality assurance system that ensures quality orientation in all aspects, from access to rehabilitation through to aftercare. Future developments such as vocationally-oriented medical rehabilitation and the use of new technologies will further improve cardiac rehabilitation. Positive patient feedback and scientific evidence of the effectiveness of cardiac rehabilitation are further incentives to maintain this forward-looking approach. PMID:22190191

  10. Output gear of automatic transmission

    SciTech Connect

    Ideta, Y.; Miida, S.

    1986-12-16

    An automatic transmission is described for a front engine, front wheel drive vehicle, comprising: a torque converter; a main power train comprising a rotatory terminal member, the main power train being connected with the torque converter for transmitting a driving torque from the torque converter to the terminal member; housing means enclosing the main power train, the housing means having a cylindrical bore and at least one oil feed passage opening in a cylindrical surface of the bore, and an output gear rotatably supported by the housing means and connected detachably with the terminal member of the main power train for transmitting the driving torque from the main power train to front wheels of the vehicle. The main power train is placed between the torque converter and the output gear, the output gear having a hub which is splined detachably to the terminal member, and which is fitting in the bore of the housing means in such a manner that the hub can rotate in the bore. The hub has an annular groove formed on an outer cylindrical surface of the hub, the output gear being formed with lubricating means extending from the annular groove for conveying oil from the annular groove, the oil feed passage of the housing means opening into the annular groove for supplying oil into the lubricating means through the annular groove. The annular groove has sufficient depth and width within a range permitted by a strength of the hub to prevent a shortage of the oil supply through the annular groove to the lubricating means due to a centrifugal force of the oil rotating in the annular groove together with walls of the annular groove.

  11. Cardiac applications of PET.

    PubMed

    Sarikaya, Ismet

    2015-10-01

    Routine use of cardiac positron emission tomography (PET) applications has been increasing but has not replaced cardiac single-photon emission computerized tomography (SPECT) studies yet. The majority of cardiac PET tracers, with the exception of fluorine-18 fluorodeoxyglucose (18F-FDG), are not widely available, as they require either an onsite cyclotron or a costly generator for their production. 18F-FDG PET imaging has high sensitivity for the detection of hibernating/viable myocardium and has replaced Tl-201 SPECT imaging in centers equipped with a PET/CT camera. PET myocardial perfusion imaging with various tracers such as Rb-82, N-13 ammonia, and O-15 H2O has higher sensitivity and specificity than myocardial perfusion SPECT for the detection of coronary artery disease (CAD). In particular, quantitative PET measurements of myocardial perfusion help identify subclinical coronary stenosis, better define the extent and severity of CAD, and detect ischemia when there is balanced reduction in myocardial perfusion due to three-vessel or main stem CAD. Fusion images of PET perfusion and CT coronary artery calcium scoring or CT coronary angiography provide additional complementary information and improve the detection of CAD. PET studies with novel 18F-labeled perfusion tracers such as 18F-flurpiridaz and 18F-FBnTP have yielded high sensitivity and specificity in the diagnosis of CAD. These tracers are still being tested in humans, and, if approved for clinical use, they will be commercially and widely available. In addition to viability studies, 18F-FDG PET can also be utilized to detect inflammation/infection in various conditions such as endocarditis, sarcoidosis, and atherosclerosis. Some recent series have obtained encouraging results for the detection of endocarditis in patients with intracardiac devices and prosthetic valves. PET tracers for cardiac neuronal imaging, such as C-11 HED, help assess the severity of heart failure and post-transplant cardiac

  12. Cardiac involvement in hemochromatosis.

    PubMed

    Gulati, Vinay; Harikrishnan, Prakash; Palaniswamy, Chandrasekar; Aronow, Wilbert S; Jain, Diwakar; Frishman, William H

    2014-01-01

    Cardiac hemochromatosis or primary iron-overload cardiomyopathy is an important and potentially preventable cause of heart failure. This is initially characterized by diastolic dysfunction and arrhythmias and in later stages by dilated cardiomyopathy. Diagnosis of iron overload is established by elevated transferrin saturation (>55%) and elevated serum ferritin (>300 ng/mL). Genetic testing for mutations in the HFE (high iron) gene and other proteins, such as hemojuvelin, transferrin receptor, and ferroportin, should be performed if secondary causes of iron overload are ruled out. Patients should undergo comprehensive 2D and Doppler echocardiography to evaluate their systolic and diastolic function. Newer modalities like strain imaging and speckle-tracking echocardiography hold promise for earlier detection of cardiac involvement. Cardiac magnetic resonance imaging with measurement of T2* relaxation times can help quantify myocardial iron overload. In addition to its value in diagnosis of cardiac iron overload, response to iron reduction therapy can be assessed by serial imaging. Therapeutic phlebotomy and iron chelation are the cornerstones of therapy. The average survival is less than a year in untreated patients with severe cardiac impairment. However, if treated early and aggressively, the survival rate approaches that of the regular heart failure population.

  13. THIS OLD HEART: CARDIAC AGING AND AUTOPHAGY

    PubMed Central

    Linton, Phyllis-Jean; Gurney, Michael; Sengstock, David; Mentzer, Robert M.; Gottlieb, Roberta A.

    2015-01-01

    Autophagy, a cellular housekeeping process, is essential to maintain tissue homeostasis, particularly in long-lived cells such as cardiomyocytes. Autophagic activity declines with age and may explain many features of age-related cardiac dysfunction. In this review we summarize the current state of knowledge regarding age-related changes in autophagy in the heart. Recent findings from studies in human hearts are presented, including evidence that the autophagic response is intact in the aged human heart. Impaired autophagic clearance of protein aggregates or deteriorating mitochondria will have multiple consequences including increased arrhythmia risk, decreased contractile function, reduced tolerance to ischemic stress, and increased inflammation; thus autophagy represents a potentially important therapeutic target to mitigate the cardiac consequences of aging. PMID:25543002

  14. Intramyocardial transplantation of cardiac telocytes decreases myocardial infarction and improves post-infarcted cardiac function in rats.

    PubMed

    Zhao, Baoyin; Liao, Zhaofu; Chen, Shang; Yuan, Ziqiang; Yilin, Chen; Lee, Kenneth K H; Qi, Xufeng; Shen, Xiaotao; Zheng, Xin; Quinn, Thomas; Cai, Dongqing

    2014-05-01

    The midterm effects of cardiac telocytes (CTs) transplantation on myocardial infarction (MI) and the cellular mechanisms involved in the beneficial effects of CTs transplantation are not understood. In the present study, we have revealed that transplantation of CTs was able to significantly decrease the infarct size and improved cardiac function 14 weeks after MI. It has established that CT transplantation exerted a protective effect on the myocardium and this was maintained for at least 14 weeks. The cellular mechanism behind this beneficial effect on MI was partially attributed to increased cardiac angiogenesis, improved reconstruction of the CT network and decreased myocardial fibrosis. These combined effects decreased the infarct size, improved the reconstruction of the LV and enhanced myocardial function in MI. Our findings suggest that CTs could be considered as a potential cell source for therapeutic use to improve cardiac repair and function following MI, used either alone or in tandem with stem cells.

  15. [Preoperative cardiac assessment before non-cardiac surgery: cardiac risk stratification].

    PubMed

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

    2010-06-01

    Perioperative cardiac events occurring in patients undergoing non-cardiac surgery are a common cause of morbidity and mortality. Current guidelines recommend an individualized approach to preoperative cardiac risk stratification prior to non-cardiac surgery, integrating risk factors both for the patient (active cardiac conditions, clinical risk factors, functional capacity) and for the planned surgery. Preoperative cardiac investigations are currently limited to high-risk patients in whom they may contribute to modify the perioperative management. A multidisciplinary approach to such patients, integrating the general practitioner, is recommended in order to define an individualized peri-operative strategy.

  16. 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.

  17. Cardiac abnormalities in children with hyperthyroidism.

    PubMed

    Lester, L A; Sodt, P C; Rich, B H; Lucky, A W; Hutcheon, N; Arcilla, R A

    1982-01-01

    The cardiac status of 18 hyperthyroid (HT) children (9 black and 9 white) was evaluated by echocardiography. Mitral regurgitation (MR) was diagnosed clinically in 33% (6 of the 9 blacks). None of the 9 white children had MR. Left ventricular end-diastolic diameter (LVEDD) and volume (LVEDV) did not differ from the predicted normal (PN) based on body surface area and heart rate, except in those with MR where increased LVEDD and LVEDV were noted (p less than 0.02). LV mass was +1.75 standard deviations (sigma) of the PN (p less than 0.01), due to increased wall thickness of LVEDV. Left ventricular output (LVO) was +0.35 sigma PN (p = ns); however, when compared to that of normal children, LVO of HT was higher (p less than 0.001) due to the increased heart rate. Enhanced left ventricular contractility was suggested by increased rate of dimensional change during ejection (peak dD/dt-syst), with a mean value of -11.39 cm/sec as compared to the normal of -9.54 cm/sec (p less than 0.01). A linear multivariate regression equation differentiated the cardiac status of HT from that of normal children. Following treatment to euthyroid state, MR disappeared in 2 and became less in 4 patients. LVO, LV mass, and peak dD/dt-syst also became less. Significant cardiac changes occur in children with hyperthyroidism, which may be reversible in part after euthyroidism is restored.

  18. Cardiac arrest in the skies.

    PubMed

    Charles, R A

    2011-08-01

    Cardiac arrest occurring on board aeroplanes is rare, but remains a common cause of inflight incidents. This review examines some of the management problems unique to inflight cardiac arrests, and emphasises the use of cardiopulmonary resuscitation and automated external defibrillators.

  19. 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

  20. 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.

  1. Perioperative management of cardiac disease.

    PubMed

    Aresti, N A; Malik, A A; Ihsan, K M; Aftab, S M E; Khan, W S

    2014-01-01

    Pre-existing cardiac disease contributes significantly to morbidity and mortality amongst patients undergoing non cardiac surgery. Patients with pre-existing cardiac disease or with risk factors for it, have as much as a 3.9% risk of suffering a major perioperative cardiac event (Lee et al 1999, Devereaux 2005). Furthermore, the incidence of perioperative myocardial infarction (MI) is increased 10 to 50 fold in patients with previous coronary events (Jassal 2008).

  2. 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

  3. Penetrating Cardiac Injury: A Review

    PubMed Central

    Lateef Wani, Mohd; Ahangar, Ab Gani; Wani, Shadab Nabi; Irshad, Ifat; Ul-Hassan, Nayeem

    2012-01-01

    Cardiac injury presents a great challenge to the emergency resident because these injuries require urgent intervention to prevent death. Sometimes serious cardiac injury may manifest only subtle or occult symptoms or signs. As there is an epidemic of cardiac injuries in Kashmir valley due to problems of law and order, we herein present a review on management of such injuries. PMID:24829887

  4. Data analysis in cardiac arrhythmias.

    PubMed

    Rodrigo, Miguel; Pedrón-Torecilla, Jorge; Hernández, Ismael; Liberos, Alejandro; Climent, Andreu M; Guillem, María S

    2015-01-01

    Cardiac arrhythmias are an increasingly present in developed countries and represent a major health and economic burden. The occurrence of cardiac arrhythmias is closely linked to the electrical function of the heart. Consequently, the analysis of the electrical signal generated by the heart tissue, either recorded invasively or noninvasively, provides valuable information for the study of cardiac arrhythmias. In this chapter, novel cardiac signal analysis techniques that allow the study and diagnosis of cardiac arrhythmias are described, with emphasis on cardiac mapping which allows for spatiotemporal analysis of cardiac signals.Cardiac mapping can serve as a diagnostic tool by recording cardiac signals either in close contact to the heart tissue or noninvasively from the body surface, and allows the identification of cardiac sites responsible of the development or maintenance of arrhythmias. Cardiac mapping can also be used for research in cardiac arrhythmias in order to understand their mechanisms. For this purpose, both synthetic signals generated by computer simulations and animal experimental models allow for more controlled physiological conditions and complete access to the organ.

  5. 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

  6. Caste ratios affect the reproductive output of social trematode colonies.

    PubMed

    Kamiya, T; Poulin, R

    2013-03-01

    Intraspecific phenotypic diversification in social organisms often leads to formation of physical castes which are morphologically specialized for particular tasks within the colony. The optimal caste allocation theory argues that specialized morphological castes are efficient at specific tasks, and hence different caste ratios should affect the ergonomic efficiency, hence reproductive output of the colony. However, the reproductive output of different caste ratios has been documented in few species of insects with equivocal support for the theory. This study investigated whether the ratios of nonreproductive and reproductive morphs affect the reproductive output of a recently discovered social trematode, Philophthalmus sp., in which the nonreproductive members are hypothesized to be defensive specialists. A census of natural infections and a manipulative in vitro experiment demonstrated a positive association between the reproductive output of trematode colonies and the ratio of nonreproductive to reproductive morphs in the presence of an intra-host trematode competitor, Maritrema novaezealandensis. On the contrary, without the competitor, reproductive output was negatively associated with the proportion of nonreproductive castes in colonies. Our findings demonstrate for the first time a clear fitness benefit associated with the nonreproductive castes in the presence of a competitor while illustrating the cost of maintaining such morphs in noncompetitive situations. Although the proximate mechanisms controlling caste ratio remain unclear in this trematode system, this study supports the prediction that the fitness of colonies is influenced by the composition of specialized functional morphs in social organisms, suggesting a potential for adaptive shifts of caste ratios over evolutionary time.

  7. 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.

  8. 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.

  9. The cardiac malpositions.

    PubMed

    Perloff, Joseph K

    2011-11-01

    Dextrocardia was known in the 17th century and was 1 of the first congenital malformations of the heart to be recognized. Fifty years elapsed before Matthew Baillie published his account of complete transposition in a human of the thoracic and abdominal viscera to the opposite side from what is natural. In 1858, Thomas Peacock stated that "the heart may be congenitally misplaced in various ways, occupying either an unusual position within the thorax, or being situated external to that cavity." In 1915, Maude Abbott described ectopia cordis, and Richard Paltauf's remarkable illustrations distinguished the various types of dextrocardia. In 1928, the first useful classification of the cardiac malpositions was proposed, and in 1966, Elliott et al's radiologic classification set the stage for clinical recognition. The first section of this review deals with the 3 basic cardiac malpositions in the presence of bilateral asymmetry. The second section deals with cardiac malpositions in the presence of bilateral left-sidedness or right-sidedness. Previous publications on cardiac malpositions are replete with an arcane vocabulary that confounds rather than clarifies. Even if the terms themselves are understood, inherent complexity weighs against clarity. This review was designed as a guided tour of an unfamiliar subject.

  10. 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…

  11. 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.

  12. 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

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

    PubMed

    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

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

    PubMed

    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.

  15. 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.

  16. 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.

  17. Hydroelectric redevelopment maintains heritage values

    SciTech Connect

    Bulkovshteyn, L.; Chidiac, M.; Hall, W.

    1995-12-31

    The Seymour GS is an 80 year old generating station on the historic Trent-Severn Waterway in Ontario, Canada. The rehabilitation at Seymour was approved by Provincial and Federal authorities on condition that the original appearance of the building be maintained. The capacity of the Generating Station (GS) is being uprated from 3.15 MW to 5.7 MW, by replacing five vertical double runner Francis units with five horizontal Kaplan turbines. The replacement of vertical Francis units with horizontal Kaplan units, necessitated an extensive and innovative demolition approach for the substructure modification. The new turbines required a powerhouse base slab 3.5 m below the grade of the original slab. This required removal of the existing slabs and foundation rock along with most of the interior powerhouse walls. The type of modification and demolition were carefully chosen to accommodate a very tight schedule dictated by the requirement of the Federal Department of Fisheries and Oceans (DFO), where in-water work is restricted to certain months of the year.

  18. 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)...

  19. 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)...

  20. 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)...

  1. 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)...

  2. 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)...

  3. 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

  4. 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

  5. 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.

  6. A dual role for integrin-linked kinase and β1-integrin in modulating cardiac aging

    PubMed Central

    Nishimura, Mayuko; Kumsta, Caroline; Kaushik, Gaurav; Diop, Soda B; Ding, Yun; Bisharat-Kernizan, Jumana; Catan, Hannah; Cammarato, Anthony; Ross, Robert S; Engler, Adam J; Bodmer, Rolf; Hansen, Malene; Ocorr, Karen

    2014-01-01

    Cardiac performance decreases with age, which is a major risk factor for cardiovascular disease and mortality in the aging human population, but the molecular mechanisms underlying cardiac aging are still poorly understood. Investigating the role of integrin-linked kinase (ilk) and β1-integrin (myospheroid, mys) in Drosophila, which colocalize near cardiomyocyte contacts and Z-bands, we find that reduced ilk or mys function prevents the typical changes of cardiac aging seen in wildtype, such as arrhythmias. In particular, the characteristic increase in cardiac arrhythmias with age is prevented in ilk and mys heterozygous flies with nearly identical genetic background, and they live longer, in line with previous findings in Caenorhabditis elegans for ilk and in Drosophila for mys. Consistent with these findings, we observed elevated β1-integrin protein levels in old compared with young wild-type flies, and cardiac-specific overexpression of mys in young flies causes aging-like heart dysfunction. Moreover, moderate cardiac-specific knockdown of integrin-linked kinase (ILK)/integrin pathway-associated genes also prevented the decline in cardiac performance with age. In contrast, strong cardiac knockdown of ilk or ILK-associated genes can severely compromise cardiac integrity, including cardiomyocyte adhesion and overall heart function. These data suggest that ilk/mys function is necessary for establishing and maintaining normal heart structure and function, and appropriate fine-tuning of this pathway can retard the age-dependent decline in cardiac performance and extend lifespan. Thus, ILK/integrin-associated signaling emerges as an important and conserved genetic mechanism in longevity, and as a new means to improve age-dependent cardiac performance, in addition to its vital role in maintaining cardiac integrity. PMID:24400780

  7. Predictors of cardiac hepatopathy in patients with right heart failure

    PubMed Central

    Megalla, Sherry; Holtzman, Dvorah; Aronow, Wilbert S.; Nazari, Reza; Korenfeld, Svetlana; Schwarcz, Aron; Goldberg, Ythan; Spevack, Daniel M.

    2011-01-01

    Summary Background Some patients with right heart failure develop cardiac hepatopathy (CH). The pathophysiology of CH is thought to be secondary to hepatic venous congestion and arterial ischemia. We sought to define the clinical and hemodynamic characteristics associated with CH. Material/Methods A retrospective cross sectional analysis was performed in which subjects were identified from our institutional cardiology database if echocardiography showed either right ventricular (RV) hypokinesis or dilatation, and was performed within 30 days of right heart catheterization. A chart review was then performed to identify patient clinical characteristics and to determine if the patients had underlying liver disease. Subjects with non-cardiac causes for hepatopathy were excluded. Results In 188 included subjects, etiology for right heart dysfunction included left heart failure (LHF), shunt, pulmonary hypertension, mitral- tricuspid- and pulmonic valvular disease. On multivariate analysis, higher RV diastolic pressure and etiology for RV dysfunction other than LHF were both associated with CH. Low cardiac output was associated with CH only amongst those without LHF. Conclusions CH is most often seen in subjects with elevated RV diastolic pressure suggesting a congestive cause in most cases. CH associated with low cardiac output in patients without LHF suggests that low flow may be contributing to the patophysiology in some cases. PMID:21959605

  8. Symmetry of cardiac function assessment.

    PubMed

    Bai, Xu-Fang; Ma, Amy X

    2016-09-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function.

  9. Symmetry of cardiac function assessment.

    PubMed

    Bai, Xu-Fang; Ma, Amy X

    2016-09-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function. PMID:27582768

  10. Symmetry of cardiac function assessment

    PubMed Central

    Bai, Xu-Fang; Ma, Amy X

    2016-01-01

    Both right and left ventricles are developed from two adjacent segments of the primary heart tube. Though they are different with regard to shape and power, they mirror each other in terms of behavior. This is the first level of symmetry in cardiac function assessment. Both cardiac muscle contraction and relaxation are active. This constructs the second level of symmetry in cardiac function assessment. Combination of the two levels will help to find some hidden indexes or approaches to evaluate cardiac function. In this article, four major indexes from echocardiography were analyzed under this principal, another seventeen indexes or measurement approaches came out of the shadow, which is very helpful in the assessment of cardiac function, especially for the right cardiac function and diastolic cardiac function. PMID:27582768

  11. 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.

  12. Hurricane Katrina: impact on cardiac surgery case volume and outcomes.

    PubMed

    Bakaeen, Faisal G; Huh, Joseph; Chu, Danny; Coselli, Joseph S; LeMaire, Scott A; Mattox, Kenneth L; Wall, Matthew J; Wang, Xing Li; Shenaq, Salwa A; Atluri, Prasad V; Awad, Samir S; Berger, David H

    2008-01-01

    Hurricane Katrina produced a surge of patient referrals to our facility for cardiac surgery. We sought to determine the impact of this abrupt volume change on operative outcomes. Using our cardiac surgery database, which is part of the Department of Veterans Affairs' Continuous Improvement in Cardiac Surgery Program, we compared procedural outcomes for all cardiac operations that were performed in the year before the hurricane (Year A, 29 August 2004-28 August 2005) and the year after (Year B, 30 August 2005-29 August 2006). Mortality was examined as unadjusted rates and as risk-adjusted observed-to-expected ratios. We identified 433 cardiac surgery cases: 143 (33%) from Year A and 290 (67%) from Year B. The operative mortality rate was 2.8% during Year A (observed-to-expected ratio, 0.4) and 2.8% during Year B (observed-to-expected ratio, 0.6) (P = 0.9). We identified several factors that enabled our institution to accommodate the increase in surgical volume during the study period. We conclude that, although Hurricane Katrina caused a sudden, dramatic increase in the number of cardiac operations that were performed at our facility, good surgical outcomes were maintained.

  13. 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

  14. Transcriptional control of cardiac fibroblast plasticity.

    PubMed

    Lighthouse, Janet K; Small, Eric M

    2016-02-01

    Cardiac fibroblasts help maintain the normal architecture of the healthy heart and are responsible for scar formation and the healing response to pathological insults. Various genetic, biomechanical, or humoral factors stimulate fibroblasts to become contractile smooth muscle-like cells called myofibroblasts that secrete large amounts of extracellular matrix. Unfortunately, unchecked myofibroblast activation in heart disease leads to pathological fibrosis, which is a major risk factor for the development of cardiac arrhythmias and heart failure. A better understanding of the molecular mechanisms that control fibroblast plasticity and myofibroblast activation is essential to develop novel strategies to specifically target pathological cardiac fibrosis without disrupting the adaptive healing response. This review highlights the major transcriptional mediators of fibroblast origin and function in development and disease. The contribution of the fetal epicardial gene program will be discussed in the context of fibroblast origin in development and following injury, primarily focusing on Tcf21 and C/EBP. We will also highlight the major transcriptional regulatory axes that control fibroblast plasticity in the adult heart, including transforming growth factor β (TGFβ)/Smad signaling, the Rho/myocardin-related transcription factor (MRTF)/serum response factor (SRF) axis, and Calcineurin/transient receptor potential channel (TRP)/nuclear factor of activated T-Cell (NFAT) signaling. Finally, we will discuss recent strategies to divert the fibroblast transcriptional program in an effort to promote cardiomyocyte regeneration. This article is a part of a Special Issue entitled "Fibrosis and Myocardial Remodeling". PMID:26721596

  15. 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.

  16. Maintaining quality in blood banking.

    PubMed

    Harvey, E; Hewison, C; Nevalainen, D E; Lloyd, H L

    1995-03-01

    component will warrant redress. The degree of fault attributed to the producer will in part depend on whether they have met the best available standards at all stages in the preparation of the product. If a Transfusion Service can show that it's operation has external accreditation, particularly to an internationally recognised standard such as ISO 9000 and they can show that staff have been properly trained, that equipment is properly supplied and maintained and that the facility is appropriate to the work being carried out, then the liability that exists when something goes wrong will be reduced.(ABSTRACT TRUNCATED AT 400 WORDS)

  17. Maintaining quality in blood banking.

    PubMed

    Harvey, E; Hewison, C; Nevalainen, D E; Lloyd, H L

    1995-03-01

    component will warrant redress. The degree of fault attributed to the producer will in part depend on whether they have met the best available standards at all stages in the preparation of the product. If a Transfusion Service can show that it's operation has external accreditation, particularly to an internationally recognised standard such as ISO 9000 and they can show that staff have been properly trained, that equipment is properly supplied and maintained and that the facility is appropriate to the work being carried out, then the liability that exists when something goes wrong will be reduced.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7795421

  18. 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.

  19. Cardiac arrhythmias in pregnancy.

    PubMed

    Knotts, Robert J; Garan, Hasan

    2014-08-01

    As more women with repaired congenital heart disease survive to their reproductive years and many other women are delaying pregnancy until later in life, a rising concern is the risk of cardiac arrhythmias during pregnancy. Naturally occurring cardiovascular changes during pregnancy increase the likelihood that a recurrence of a previously experienced cardiac arrhythmia or a de novo arrhythmia will occur. Arrhythmias should be thoroughly investigated to determine if there is a reversible etiology, and risks/benefits of treatment options should be fully explored. We discuss the approach to working up and treating various arrhythmias during pregnancy with attention to fetal and maternal risks as well as treatment of fetal arrhythmias. Acute management in stable patients includes close monitoring and intravenous pharmacologic therapy, while DC cardioversion should be used to terminate arrhythmias in hemodynamically unstable patients. Long-term management may require continued oral antiarrhythmic therapy, with particular attention to fetal safety, to prevent complications associated with arrhythmias.

  20. Recovery after cardiac events.

    PubMed

    Davidson, D M; Maloney, C A

    1985-12-01

    This article describes an interdisciplinary program of cardiac rehabilitation that integrates physical therapy with medical, nursing, nutritional, and psychological assessment and treatment. Hospitalized patients recovering from myocardial infarction or cardiac surgery progress through a seven-level program of physical activity, education, and emotional support. These components of the program continue during their early home period and again are integrated during the active training period. In the active training period, patients participate in support groups and receive nutritional, exercise, and medical education and engage in one hour of exercise three times weekly. In all phases, considerable attention is given to the development of behavioral skills necessary for long-term adherence to healthy life style habits.

  1. 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.

  2. 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

  3. Polarization maintaining linear cavity Er-doped fiber femtosecond laser

    NASA Astrophysics Data System (ADS)

    Jang, Heesuk; Jang, Yoon-Soo; Kim, Seungman; Lee, Keunwoo; Han, Seongheum; Kim, Young-Jin; Kim, Seung-Woo

    2015-10-01

    We present a polarization-maintaining (PM) type of Er-doped fiber linear oscillator designed to produce femtosecond laser pulses with high operational stability. Mode locking is activated using a semiconductor saturable absorber mirror (SESAM) attached to one end of the linear PM oscillator. To avoid heat damage, the SESAM is mounted on a copper-silicon-layered heat sink and connected to the linear oscillator through a fiber buffer dissipating the residual pump power. A long-term stability test is performed to prove that the proposed oscillator design maintains a soliton-mode single-pulse operation without breakdown of mode locking over a week period. With addition of an Er-doped fiber amplifier, the output power is raised to 180 mW with 60 fs pulse duration, from which an octave-spanning supercontinuum is produced.

  4. The Role of Cardiac Side Population Cells in Cardiac Regeneration

    PubMed Central

    Yellamilli, Amritha; van Berlo, Jop H.

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies.

  5. The Role of Cardiac Side Population Cells in Cardiac Regeneration

    PubMed Central

    Yellamilli, Amritha; van Berlo, Jop H.

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies. PMID:27679798

  6. The Role of Cardiac Side Population Cells in Cardiac Regeneration.

    PubMed

    Yellamilli, Amritha; van Berlo, Jop H

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies.

  7. The Role of Cardiac Side Population Cells in Cardiac Regeneration.

    PubMed

    Yellamilli, Amritha; van Berlo, Jop H

    2016-01-01

    The heart has a limited ability to regenerate. It is important to identify therapeutic strategies that enhance cardiac regeneration in order to replace cardiomyocytes lost during the progression of heart failure. Cardiac progenitor cells are interesting targets for new regenerative therapies because they are self-renewing, multipotent cells located in the heart. Cardiac side population cells (cSPCs), the first cardiac progenitor cells identified in the adult heart, have the ability to differentiate into cardiomyocytes, endothelial cells, smooth muscle cells, and fibroblasts. They become activated in response to cardiac injury and transplantation of cSPCs into the injured heart improves cardiac function. In this review, we will discuss the current literature on the progenitor cell properties and therapeutic potential of cSPCs. This body of work demonstrates the great promise cSPCs hold as targets for new regenerative strategies. PMID:27679798

  8. 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

  9. 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.

  10. Some aspects of the NASTRAN program output

    NASA Technical Reports Server (NTRS)

    Gregory, D. J.

    1972-01-01

    The NASTRAN program output is discussed from a structural analysts point of view, and the simple modifications which were made to the program in order to improve it are also described. The convenience of the output for use in original design work is critically appraised and compared with the output from ASTRAL. It is shown that considerable hand calculation is necessary in order to extract useful load distribution data from the available NASTRAN output. For this reason, some effort was directed toward providing additional force output for the NASTRAN shear panel element.

  11. Cardiac Signatures of Personality

    PubMed Central

    Koelsch, Stefan; Enge, Juliane; Jentschke, Sebastian

    2012-01-01

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

  12. Cardiac outflow tract anomalies

    PubMed Central

    Neeb, Zachary; Lajiness, Jacquelyn D.; Bolanis, Esther; Conway, Simon J

    2014-01-01

    The mature outflow tract (OFT) is, in basic terms, a short conduit. It is a simple, although vital, connection situated between contracting muscular heart chambers and a vast embryonic vascular network. Unfortunately, it is also a focal point underlying many multifactorial congenital heart defects (CHDs). Through the use of various animal models combined with human genetic investigations, we are beginning to comprehend the molecular and cellular framework that controls OFT morphogenesis. Clear roles of neural crest cells (NCC) and second heart field (SHF) derivatives have been established during OFT formation and remodeling. The challenge now is to determine how the SHF and cardiac NCC interact, the complex reciprocal signaling that appears to be occurring at various stages of OFT morphogenesis, and finally how endocardial progenitors and primary heart field (PHF) communicate with both these colonizing extra-cardiac lineages. Although we are beginning to understand that this dance of progenitor populations is wonderfully intricate, the underlying pathogenesis and the spatiotemporal cell lineage interactions remain to be fully elucidated. What is now clear is that OFT alignment and septation are independent processes, invested via separate SHF and cardiac neural crest (CNC) lineages. This review will focus on our current understanding of the respective contributions of the SHF and CNC lineage during OFT development and pathogenesis. PMID:24014420

  13. 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

  14. 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

  15. 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.

  16. The left ventricle as a mechanical engine: from Leonardo da Vinci to the echocardiographic assessment of peak power output-to-left ventricular mass.

    PubMed

    Dini, Frank L; Guarini, Giacinta; Ballo, Piercarlo; Carluccio, Erberto; Maiello, Maria; Capozza, Paola; Innelli, Pasquale; Rosa, Gian M; Palmiero, Pasquale; Galderisi, Maurizio; Razzolini, Renato; Nodari, Savina

    2013-03-01

    The interpretation of the heart as a mechanical engine dates back to the teachings of Leonardo da Vinci, who was the first to apply the laws of mechanics to the function of the heart. Similar to any mechanical engine, whose performance is proportional to the power generated with respect to weight, the left ventricle can be viewed as a power generator whose performance can be related to left ventricular mass. Stress echocardiography may provide valuable information on the relationship between cardiac performance and recruited left ventricular mass that may be used in distinguishing between adaptive and maladaptive left ventricular remodeling. Peak power output-to-mass, obtained during exercise or pharmacological stress echocardiography, is a measure that reflects the number of watts that are developed by 100 g of left ventricular mass under maximal stimulation. Power output-to-mass may be calculated as left ventricular power output per 100 g of left ventricular mass: 100× left ventricular power output divided by left ventricular mass (W/100 g). A simplified formula to calculate power output-to-mass is as follows: 0.222 × cardiac output (l/min) × mean blood pressure (mmHg)/left ventricular mass (g). When the integrity of myocardial structure is compromised, a mismatch becomes apparent between maximal cardiac power output and left ventricular mass; when this occurs, a reduction of the peak power output-to-mass index is observed.

  17. 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.

  18. 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

  19. PULMONARY HEPATIC FLOW DISTRIBUTION IN TOTAL CAVOPULMONARY CONNECTIONS: EXTRA CARDIAC VS INTRA CARDIAC

    PubMed Central

    Dasi, Lakshmi P.; Whitehead, Kevin; Pekkan, Kerem; de Zelicourt, Diane; Sundareswaran, Kartik; Kanter, Kirk; Fogel, Mark A.; Yoganathan, Ajit P.

    2010-01-01

    Background Pulmonary arteriovenous malformations (PAVMs) can occur after the Fontan and are believed to be associated with disproportionate pulmonary distribution of hepatic venous effluent. We studied the impact of total cavo-pulmonary connection (TCPC) geometry and the effect of increased cardiac output (CO) on distribution of inferior vena caval (IVC) return to the lungs. Methods 10 Fontan patients – 5 with extra-cardiac (EC) and 5 with intra-cardiac (IC) configurations of the TCPC previously analyzed for power loss were processed for calculating the distribution of inferior vena caval return to the lungs (2nd order accuracy). One idealized TCPC was similarly analyzed under parametric variation of IVC offset and CO flow split Results Streaming of the IVC return in the idealized TCPC model was dependent on both IVC offset magnitude and CO flow split ratio. For patient-specific TCPCs, preferential streaming of the IVC return was directly proportional to CO flow split ratio in the IC type TCPCs (p < 0.0001). Preferential streaming in EC TCPCs correlated to the IVC offset (p<0.05) and did not correlate to CO flow split. Enhanced mixing in IC is speculated to explain the contrasting results. Exercising tends to reduce streaming towards LPA in IC, while for EC, exercising tends to equalize the streaming. Conclusions EC and IC TCPCs have inherently different streaming characteristics due to contrasting mixing characteristics owing to their geometric differences. PA diameters and IVC offsets may together determine hepatic flow streaming. PMID:20621314

  20. An overview of cardiac morphogenesis.

    PubMed

    Schleich, Jean-Marc; Abdulla, Tariq; Summers, Ron; Houyel, Lucile

    2013-11-01

    Accurate knowledge of normal cardiac development is essential for properly understanding the morphogenesis of congenital cardiac malformations that represent the most common congenital anomaly in newborns. The heart is the first organ to function during embryonic development and is fully formed at 8 weeks of gestation. Recent studies stemming from molecular genetics have allowed specification of the role of cellular precursors in the field of heart development. In this article we review the different steps of heart development, focusing on the processes of alignment and septation. We also show, as often as possible, the links between abnormalities of cardiac development and the main congenital heart defects. The development of animal models has permitted the unraveling of many mechanisms that potentially lead to cardiac malformations. A next step towards a better knowledge of cardiac development could be multiscale cardiac modelling. PMID:24138816

  1. 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

  2. Transpulmonary thermodilution-derived cardiac function index identifies cardiac dysfunction in acute heart failure and septic patients: an observational study

    PubMed Central

    2009-01-01

    Introduction There is limited clinical experience with the single-indicator transpulmonary thermodilution (pulse contour cardiac output, or PiCCO) technique in critically ill medical patients, particularly in those with acute heart failure (AHF). Therefore, we compared the cardiac function of patients with AHF or sepsis using the pulmonary artery catheter (PAC) and the PiCCO technology. Methods This retrospective observational study was conducted in the medical intensive care unit of a university hospital. Twelve patients with AHF and nine patients with severe sepsis or septic shock had four simultaneous hemodynamic measurements by PAC and PiCCO during a 24-hour observation period. Comparisons between groups were made with the use of the Mann-Whitney U test. Including all measurements, correlations between data pairs were established using linear regression analysis and are expressed as the square of Pearson's correlation coefficients (r2). Results Compared to septic patients, AHF patients had a significantly lower cardiac index, cardiac function index (CFI), global ejection fraction, mixed venous oxygen saturation (SmvO2) and pulmonary vascular permeability index, but higher pulmonary artery occlusion pressure. All patients with a CFI less than 4.5 per minute had an SmvO2 not greater than 70%. In both groups, the CFI correlated with the left ventricular stroke work index (sepsis: r2 = 0.30, P < 0.05; AHF: r2 = 0.23, P < 0.05) and cardiac power (sepsis: r2 = 0.39, P < 0.05; AHF: r2 = 0.45, P < 0.05). Conclusions In critically ill medical patients, assessment of cardiac function using transpulmonary thermodilution technique is an alternative to the PAC. A low CFI identifies cardiac dysfunction in both AHF and septic patients. PMID:19671146

  3. 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.

  4. 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.

  5. 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.

  6. Sudden Cardiac Death in Athletes.

    PubMed

    Wasfy, Meagan M; Hutter, Adolph M; Weiner, Rory B

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  7. Sudden Cardiac Death in Athletes

    PubMed Central

    Wasfy, Meagan M.; Hutter, Adolph M.; Weiner, Rory B.

    2016-01-01

    There are clear health benefits to exercise; even so, patients with cardiac conditions who engage in exercise and athletic competition may on rare occasion experience sudden cardiac death (SCD). This article reviews the epidemiology and common causes of SCD in specific athlete populations. There is ongoing debate about the optimal mechanism for SCD prevention, specifically regarding the inclusion of the ECG and/or cardiac imaging in routine preparticipation sports evaluation. This controversy and contemporary screening recommendations are also reviewed. PMID:27486488

  8. PREVIMER : Meteorological inputs and outputs

    NASA Astrophysics Data System (ADS)

    Ravenel, H.; Lecornu, F.; Kerléguer, 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 Océanographique de la Marine, SHOM), the French National Weather Service (Météo-France), the French public science and technology research institute (Institut de Recherche pour le Développement, IRD), the European Institute of Marine Studies (Institut Universitaire Européen 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

  9. Autophagy in cardiac metabolic control: Novel mechanisms for cardiovascular disorders.

    PubMed

    Yang, Yufei; Zhao, Cong; Yang, Pingzhen; Wang, Xianbao; Wang, Lizi; Chen, Aihua

    2016-09-01

    As an extensively studied quality control system, autophagy is responsible for clearance of dysfunctional organelles and damaged marcomolecules in cells. In addition to its biological recycling function, autophagy plays a significant role in the pathogenesis of metabolic syndromes such as obesity and diabetes. In particular, metabolic disorders contribute to cardiovascular disease development. As energy required to maintain cardiac cells functional is immense, disturbances in the balance between anabolic and catabolic metabolism possibly contribute to cardiovascular disorders. Therefore, an urgent need to expand our knowledge on the role of autophagy on the metabolic regulation of hearts emerges. In this review, the potential relationship between autophagic activity and cardiac metabolism is explored and we also discuss how dysregulated autophagy leads to severe cardiac disorders from the perspective of metabolic control. PMID:27191043

  10. Cardiac size during prenatal development.

    PubMed

    Jordaan, H V

    1987-06-01

    In this study, the cardiac circumference as measured in a four-chamber view was analyzed to determine its relationship to three linear, sonar measurements--biparietal diameter, femoral length, and abdominal circumference--and two sonographically derived fetal parameters--gestational age and estimated fetal weight. The results showed that the cardiac circumference correlates significantly with these direct and derived variables. It is recommended that the magnitude of the cardiac circumference as a function of any or all of these variables be used as an index of organ size when assessing fetuses at risk for anomalous cardiac development.

  11. Registry of Unexplained Cardiac Arrest

    ClinicalTrials.gov

    2016-05-16

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

  12. Salacia oblonga root improves cardiac lipid metabolism in Zucker diabetic fatty rats: modulation of cardiac PPAR-alpha-mediated transcription of fatty acid metabolic genes.

    PubMed

    Huang, Tom Hsun-Wei; Yang, Qinglin; Harada, Masaki; Uberai, Jasna; Radford, Jane; Li, George Q; Yamahara, Johji; Roufogalis, Basil D; Li, Yuhao

    2006-01-01

    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. PMID:16129467

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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

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

    PubMed

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

    2013-09-01

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

  19. Cardiac-specific overexpression of inducible nitric oxide synthase does not result in severe cardiac dysfunction.

    PubMed

    Heger, Jacqueline; Gödecke, Axel; Flögel, Ulrich; Merx, Marc W; Molojavyi, Andrei; Kühn-Velten, W Nikolaus; Schrader, Jürgen

    2002-01-11

    Nitric oxide (NO), a potent regulator of myocardial contractility, has been implicated in the development of heart failure; however, no study exists describing the relation between expression of inducible nitric oxide synthase (iNOS), formation of NO in vivo, and cardiac contractility. We have therefore generated transgenic (TG) mice overexpressing iNOS under the cardiospecific alpha-myosin heavy chain (alpha-MHC) promoter. In vitro, iNOS activity in hearts of two transgenic lines was 260- to 400-fold above controls (wild type [WT]), but TG mice were viable and appeared normal. Ventricular mass/body weight ratio did not differ; heart rate and cardiac output as well as mean arterial blood pressure were decreased by 10%. NO(x) levels of hearts and blood of TG mice were 2.5- and 2-fold above WT controls, respectively. In the isolated heart, release of the NO oxidation products nitrate and nitrite, an index of in vivo NOS activity, was 40-fold over WT. However, cardiac hemodynamics and levels of ATP and phosphocreatine were unaltered. The high iNOS activity was associated with reduced cardiac L-arginine in TG hearts to only 15% of the WT, indicating limited substrate availability, whereas L-citrulline was 20-fold elevated. Our findings demonstrate that the heart can tolerate high levels of iNOS activity without detrimental functional consequences. The concept that iNOS-derived NO is the triggering factor in the pathomechanism leading to heart failure therefore needs to be reevaluated. PMID:11786524

  20. Cardiac-specific overexpression of inducible nitric oxide synthase does not result in severe cardiac dysfunction.

    PubMed

    Heger, Jacqueline; Gödecke, Axel; Flögel, Ulrich; Merx, Marc W; Molojavyi, Andrei; Kühn-Velten, W Nikolaus; Schrader, Jürgen

    2002-01-11

    Nitric oxide (NO), a potent regulator of myocardial contractility, has been implicated in the development of heart failure; however, no study exists describing the relation between expression of inducible nitric oxide synthase (iNOS), formation of NO in vivo, and cardiac contractility. We have therefore generated transgenic (TG) mice overexpressing iNOS under the cardiospecific alpha-myosin heavy chain (alpha-MHC) promoter. In vitro, iNOS activity in hearts of two transgenic lines was 260- to 400-fold above controls (wild type [WT]), but TG mice were viable and appeared normal. Ventricular mass/body weight ratio did not differ; heart rate and cardiac output as well as mean arterial blood pressure were decreased by 10%. NO(x) levels of hearts and blood of TG mice were 2.5- and 2-fold above WT controls, respectively. In the isolated heart, release of the NO oxidation products nitrate and nitrite, an index of in vivo NOS activity, was 40-fold over WT. However, cardiac hemodynamics and levels of ATP and phosphocreatine were unaltered. The high iNOS activity was associated with reduced cardiac L-arginine in TG hearts to only 15% of the WT, indicating limited substrate availability, whereas L-citrulline was 20-fold elevated. Our findings demonstrate that the heart can tolerate high levels of iNOS activity without detrimental functional consequences. The concept that iNOS-derived NO is the triggering factor in the pathomechanism leading to heart failure therefore needs to be reevaluated.

  1. UPDATE: CARDIAC XENOTRANSPLANTATION

    PubMed Central

    Ekser, Burcin; Cooper, David K.C.

    2009-01-01

    Purpose of review To review the latest development in cardiac xenotransplantation in small and large animal models and related in vitro studies. Recent findings With the recent introduction of α1,3-galactosyltransferase gene-knockout (GT-KO) pig organs for xenotransplantation, improved cardiac graft survival has been obtained. However, this experience has demonstrated the importance of pig antigens other than Galα1,3Gal (Gal) antigens (so-called nonGal antigens) as targets for primate anti-pig antibodies. Several in vitro studies have confirmed that, although the incidence and levels of anti-nonGal antibodies in non-human primates and humans are significantly less when compared with total anti-pig antibodies (i.e., anti-Gal + anti-nonGal), they can result in complement-mediated lysis of GT-KO pig cells. More recently, it has been demonstrated that regulatory T cells (Treg) suppress the cellular xenogeneic response, thus potentially preventing or reducing T cell-mediated rejection. The importance of thrombotic microangiopathy as a feature of the immune/inflammatory response and incompatibilities between the coagulation-anticoagulation systems of pig and primate are receiving increasing attention. Development of GT-KO pigs transgenic for one or more ‘anti-thrombotic’ genes, e.g., CD39 or tissue factor pathway inhibitor, may contribute to overcoming these problems. Summary Although GT-KO pigs have provided an advance over wild-type pigs as a source of Organs for transplantation into primates, further genetic modification of GT-KO pigs is required to overcome the remaining immune barriers before a clinical trial of cardiac xenotransplantation can be contemplated. PMID:19060538

  2. Output order in immediate serial recall.

    PubMed

    Tan, Lydia; Ward, Geoff

    2007-07-01

    In two experiments, we examined the effect of output order in immediate serial recall (ISR). In Experiment 1, three groups of participants saw lists of eight words and wrote down the words in the rows corresponding to their serial positions in an eight-row response grid. One group was precued to respond in forward order, a second group was precued to respond in any order, and a third group was postcued for response order. There were significant effects of output order, but not of cue type. Relative to the forward output order, the free output order led to enhanced recency and diminished primacy, with superior performance for words output early in recall. These results were replicated in Experiment 2 using six-item lists, which further suggests that output order plays an important role in the primacy effect in ISR and that the recency items are most highly accessible at recall.

  3. Exercise efficiency of low power output cycling.

    PubMed

    Reger, M; Peterman, J E; Kram, R; Byrnes, W C

    2013-12-01

    Exercise efficiency at low power outputs, energetically comparable to daily living activities, can be influenced by homeostatic perturbations (e.g., weight gain/loss). However, an appropriate efficiency calculation for low power outputs used in these studies has not been determined. Fifteen active subjects (seven females, eight males) performed 14, 5-min cycling trials: two types of seated rest (cranks vertical and horizontal), passive (motor-driven) cycling, no-chain cycling, no-load cycling, cycling at low (10, 20, 30, 40 W), and moderate (50, 60, 80, 100, 120 W) power outputs. Mean delta efficiency was 57% for low power outputs compared to 41.3% for moderate power outputs. Means for gross (3.6%) and net (5.7%) efficiencies were low at the lowest power output. At low power outputs, delta and work efficiency values exceeded theoretical values. In conclusion, at low power outputs, none of the common exercise efficiency calculations gave values comparable to theoretical muscle efficiency. However, gross efficiency and the slope and intercept of the metabolic power vs mechanical power output regression provide insights that are still valuable when studying homeostatic perturbations.

  4. Development of the cardiac conduction system in zebrafish.

    PubMed

    Poon, Kar-Lai; Liebling, Michael; Kondrychyn, Igor; Brand, Thomas; Korzh, Vladimir

    2016-07-01

    The cardiac conduction system (CCS) propagates and coordinates the electrical excitation that originates from the pacemaker cells, throughout the heart, resulting in rhythmic heartbeat. Its defects result in life-threatening arrhythmias and sudden cardiac death. Understanding of the factors involved in the formation and function of the CCS remains incomplete. By transposon assisted transgenesis, we have developed enhancer trap (ET) lines of zebrafish that express fluorescent protein in the pacemaker cells at the sino-atrial node (SAN) and the atrio-ventricular region (AVR), termed CCS transgenics. This expression pattern begins at the stage when the heart undergoes looping morphogenesis at 36 h post fertilization (hpf) and is maintained into adulthood. Using the CCS transgenics, we investigated the effects of perturbation of cardiac function, as simulated by either the absence of endothelium or hemodynamic stimulation, on the cardiac conduction cells, which resulted in abnormal compaction of the SAN. To uncover the identity of the gene represented by the EGFP expression in the CCS transgenics, we mapped the transposon integration sites on the zebrafish genome to positions in close proximity to the gene encoding fibroblast growth homologous factor 2a (fhf2a). Fhf2a is represented by three transcripts, one of which is expressed in the developing heart. These transgenics are useful tools for studies of development of the CCS and cardiac disease. PMID:27593944

  5. 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

    2014-06-10

    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

  6. Capillary Force Lithography for Cardiac Tissue Engineering

    PubMed Central

    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 worldwide1. 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 scale2. Local mechanical loading conditions and cell-ECM interactions have recently been recognized as vital components in cardiac tissue engineering3-5. A large portion of the cardiac ECM is composed of aligned collagen fibers with nano-scale diameters that significantly influences tissue architecture and electromechanical coupling2. 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 heart6-9. 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 function10-14. 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), respectively15,16. Briefly, PU or PLGA pre-polymer is drop dispensed onto a glass coverslip and the PUA

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Cardiovascular anatomy and cardiac function in the air-breathing swamp eel (Monopterus albus).

    PubMed

    Iversen, Nina K; Lauridsen, Henrik; Do, Thi Thanh Huong; Nguyen, Van Cong; Gesser, Hans; Buchanan, Rasmus; Bayley, Mark; Pedersen, Michael; Wang, Tobias

    2013-01-01

    Monopterus albus, a swamp eel inhabiting the freshwaters of South East Asia, relies on an extensive vascularisation of the buccal cavity, pharynx and anterior oesophagus for gas exchange, while the gills are much reduced. In the present study we describe the macro-circulation in the cephalic region and the vascularisation of the buccal cavity of M. albus using vascular fillings and micro-computed tomography (μCT). We also show that M. albus has the capacity to use the buccal cavity for aquatic gas exchange, being able to maintain normal arterial blood gas composition, blood pressure, heart rate and cardiac output throughout 10h of forced submergence. M. albus therefore can be characterised as a facultative air-breather. Because M. albus aestivates for many months in moist mud during the dry season we characterised in vivo cardiovascular function during exposure to anoxia as well as the effects of anoxia on in vitro contractility of strip preparations from atria and ventricle. Both studies revealed a low anoxia tolerance, rendering it unlikely that M. albus can survive prolonged exposure to anoxia.

  12. 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…

  13. Psychological aspects of cardiac arrhythmia.

    PubMed

    Lynch, J J; Paskewitz, D A; Gimbel, K S; Thomas, S A

    1977-05-01

    A review of data from a wide spectrum of research studies suggests that psychological-emotional factors can significantly influence and alter the incidence of cardiac arrhythmia. While the existing data are, in many cases, difficult to interpret because of theoretical and methodological problems, sufficient evidence does exist to warrant a concerted investigation into the total involvement of psychological factors in cardiac arrhythmia.

  14. Ictal Cardiac Ryhthym Abnormalities

    PubMed Central

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic–clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  15. Ictal Cardiac Ryhthym Abnormalities.

    PubMed

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic-clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  16. 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

  17. Interventional cardiac catheterization.

    PubMed

    Pihkala, J; Nykanen, D; Freedom, R M; Benson, L N

    1999-04-01

    Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart lesions. These procedures may be broadly grouped as dilations (e.g., septostomy, valvuloplasty, angioplasty, and endovascular stenting) or as closures (e.g., vascular embolization and device closure of defects). Balloon valvuloplasty has become the treatment of choice for patients in all age groups with simple valvar pulmonic stenosis and, although not curative, seems at least comparable to surgery for congenital aortic stenosis in newborns to young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Stents are useful in dilating lesions of which the intrinsic elasticity results in vessel recoil after balloon dilation alone. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although some devices remain investigational, they have been successfully used for closure of many arterial ducts and atrial and ventricular septal defects. In the therapy for patients with complex CHD, best results may be achieved by combining cardiac surgery with interventional catheterization. The cooperation among interventional cardiologists and cardiac surgeons was highlighted in a report of an algorithm to manage patients with tetralogy of Fallot or pulmonary atresia with diminutive pulmonary arteries, involving balloon dilation, coil embolization of collaterals, and intraoperative stent placement. In this setting, well-planned catheterization procedures have an important role in reducing the overall number of procedures that patients may require over a lifetime, with improved outcomes.

  18. Leadership in cardiac surgery.

    PubMed

    Rao, Christopher; Patel, Vanash; Ibrahim, Michael; Ahmed, Kamran; Wong, Kathie A; Darzi, Ara; von Segesser, Ludwig K; Athanasiou, Thanos

    2011-06-01

    Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importance.

  19. 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

  20. 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

  1. 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

  2. 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.

  3. Space maintainers in dentistry: past to present.

    PubMed

    Setia, Vikas; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Sekhon, Harveen Kaur

    2013-10-01

    Early orthodontic interventions are often initiated in the developing dentition to promote favourable developmental changes. Interceptive orthodontic can eliminate or reduce the severity of a developing malocclusion, the complexity of orthodontic treatment, overall treatment time and cost. The safest way to prevent future malocclusions from tooth loss is to place a space maintainer that is effective and durable. An appropriate use of space maintainer is advocated to hold the space until the eruption of permanent teeth. This case report describes the various changing trends in use of space maintainers: conventional band and loop, prefabricated band with custom made loop and glass fibre reinforced composite resins as space maintainers.

  4. Space Maintainers in Dentistry: Past to Present

    PubMed Central

    Setia, Vikas; Pandit, Inder Kumar; Srivastava, Nikhil; Gugnani, Neeraj; Sekhon, Harveen Kaur

    2013-01-01

    Early orthodontic interventions are often initiated in the developing dentition to promote favourable developmental changes. Interceptive orthodontic can eliminate or reduce the severity of a developing malocclusion, the complexity of orthodontic treatment, overall treatment time and cost. The safest way to prevent future malocclusions from tooth loss is to place a space maintainer that is effective and durable. An appropriate use of space maintainer is advocated to hold the space until the eruption of permanent teeth. This case report describes the various changing trends in use of space maintainers: conventional band and loop, prefabricated band with custom made loop and glass fibre reinforced composite resins as space maintainers. PMID:24298544

  5. 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.

  6. 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.

  7. Estimation of cardiac output and total peripheral resistance in preterm infants by arterial waveform analysis.

    PubMed

    Zhang, Ying; Chan, Gregory S H; Tracy, Mark B; Hinder, Murray; Redmond, Stephen J; Savkin, Andrey V; Lovell, Nigel H

    2013-01-01

    This study investigated whether arterial blood pressure waveform analysis could be useful for estimating left ventricular outflow (LVO) and total peripheral resistance (TPR) in preterm infants. A cohort of 27 infants were studied, with 89 measurements of left ventricular outflow (LVO) using Doppler echocardiography and arterial pressure using catheters, performed in 0, 12, 24 and 36 hours after birth. TPR was computed as mean arterial pressure divided by LVO. The diastolic decay rate (1/τ) was obtained via fitting an exponential function to the last one third of each arterial pulse, with the mean rate computed from 50 pulses selected from each infant. This decay rate was considered to be inversely related to TPR while positively related to LVO. The results of regression analysis have confirmed that the diastolic decay rate had significant positive and negative relationships with LVO and TPR respectively(r = 0.383, P = 0.0002 and r = -0.379, P = 0.0002 respectively). These preliminary results demonstrated the potential utility of arterial pressure waveform analysis for estimating LVO and TPR in preterm infants, but more advanced multi-parameter models may be needed to improve accuracy of the estimation.

  8. 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.

  9. 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.

  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. 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…

  12. 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…

  13. 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

  14. Output beam analysis of high power COIL

    NASA Astrophysics Data System (ADS)

    Yu, Deli; Sang, Fengting; Jin, Yuqi; Sun, Yizhu

    2003-03-01

    As the output power of a chemical oxygen iodine laser (COIL) increases, the output laser beam instability appears as the far-field beam spot drift and deformation for the large Fresnel number unstable resonator. In order to interpret this phenomenon, an output beam mode simulation code was developed with the fast Fourier transform method. The calculation results show that the presence of the nonuniform gain in COIL produces a skewed output intensity distribution, which causes the mirror tilt and bulge due to the thermal expansion. With the output power of COIL increases, the mirror surfaces, especially the back surface of the scraper mirror, absorb more and more heat, which causes the drift and deformation of far field beam spot seriously. The initial misalignment direction is an important factor for the far field beam spot drifting and deformation.

  15. Nonlinearities in Magnetostrictive Transducer Dynamic Output

    NASA Astrophysics Data System (ADS)

    Flatau, Alison; Faidley, L. E.; Calkins, F. T.; Dapino, M. J.

    1997-03-01

    We have designed a magnetostrictive transducer for use in characterizing material properties of 11.5 cm long by 1.27 cm diameter cylindrical samples of the magnetostrictive material Terfenol-D. The material studied is a commercially available Terfenol-D, made using a modified Brigman manufacturing process. Output displacements in the stiffness controlled portion of the transducer's dynamic range (as loaded, up to 1000 Hz) were measured using a LVDT. Trends in output were observed as controlled changes in operating conditions were made. Excitation frequency, amplitude of magnetic excitation, and prestress were varied independently as other operating conditions (including temperature, mass load, and magnetic bias) were held fixed. Data are presented demonstrating distinct nonlinearities associated with a monotonic decrease in output with increased excitation frequency, a monotonic increase in output with increased excitation amplitude, and an initial increase followed by a decrease in output with increased prestress.

  16. 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.

  17. 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.

  18. 7 CFR 784.12 - Maintaining records.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Maintaining records. 784.12 Section 784.12 Agriculture Regulations of the Department of Agriculture (Continued) FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE SPECIAL PROGRAMS 2004 EWE LAMB REPLACEMENT AND RETENTION PAYMENT PROGRAM § 784.12 Maintaining...

  19. An Unexpected Effect: Restitution Maintains Object Throwing.

    ERIC Educational Resources Information Center

    Jensen, Mary

    1988-01-01

    This study examined effects of restitution on object throwing behavior of an adolescent male with severe mental retardation. Restitution was shown to maintain throwing behavior. When the subject was not forced to pick up what he threw (no restitution), throwing dropped to zero and was maintained at a very low rate. (Author/PB)

  20. The Cost of Maintaining Educational Communications Equipment.

    ERIC Educational Resources Information Center

    Humphrey, David A.

    Tentative formulas for calculating the cost of maintaining educational communications equipment are proposed. The formulas are based on a survey of campuses of the State University of New York. The survey analyzed the types of equipment to be maintained, types of maintenance, who uses the equipment, who services the equipment, and the cost…

  1. 42 CFR 431.230 - Maintaining services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Maintaining services. 431.230 Section 431.230 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Applicants and Recipients Procedures § 431.230 Maintaining services. (a) If the agency mails the 10-day or...

  2. 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.

  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. 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.

  5. 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

  6. Trends in cardiac pacemaker batteries.

    PubMed

    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

  7. The Pathogenesis of Cardiac Fibrosis

    PubMed Central

    Kong, Ping; Christia, Panagiota; Frangogiannis, Nikolaos G

    2013-01-01

    Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. This review manuscript discusses the cellular effectors and molecular pathways implicated in the pathogenesis of cardiac fibrosis. Although activated myofibroblasts are the main effector cells in the fibrotic heart, monocytes/macrophages, lymphocytes, mast cells, vascular cells and cardiomyocytes may also contribute to the fibrotic response by secreting key fibrogenic mediators. Inflammatory cytokines and chemokines, reactive oxygen species, mast cell-derived proteases, endothelin-1, the renin/angiotensin/aldosterone system, matricellular proteins and growth factors (such as TGF-β and PDGF) are some of the best-studied mediators implicated in cardiac fibrosis. Both experimental and clinical evidence suggests that cardiac fibrotic alterations may be reversible. Understanding the mechanisms responsible for initiation, progression and resolution of cardiac fibrosis is crucial to design anti-fibrotic treatment strategies for patients with heart disease. PMID:23649149

  8. 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.

  9. Dilated cardiomyopathy and impaired cardiac hypertrophic response to angiotensin II in mice lacking FGF-2

    PubMed Central

    Pellieux, Corinne; Foletti, Alessandro; Peduto, Giovanni; Aubert, Jean-François; Nussberger, Jürg; Beermann, Friedrich; Brunner, Hans-R.; Pedrazzini, Thierry

    2001-01-01

    FGF-2 has been implicated in the cardiac response to hypertrophic stimuli. Angiotensin II (Ang II) contributes to maintain elevated blood pressure in hypertensive individuals and exerts direct trophic effects on cardiac cells. However, the role of FGF-2 in Ang II–induced cardiac hypertrophy has not been established. Therefore, mice deficient in FGF-2 expression were studied using a model of Ang II–dependent hypertension and cardiac hypertrophy. Echocardiographic measurements show the presence of dilated cardiomyopathy in normotensive mice lacking FGF-2. Moreover, hypertensive mice without FGF-2 developed no compensatory cardiac hypertrophy. In wild-type mice, hypertrophy was associated with a stimulation of the c-Jun N-terminal kinase, the extracellular signal regulated kinase, and the p38 kinase pathways. In contrast, mitogen-activated protein kinase (MAPK) activation was markedly attenuated in FGF-2–deficient mice. In vitro, FGF-2 of fibroblast origin was demonstrated to be essential in the paracrine stimulation of MAPK activation in cardiomyocytes. Indeed, fibroblasts lacking FGF-2 expression have a defective capacity for releasing growth factors to induce hypertrophic responses in cardiomyocytes. Therefore, these results identify the cardiac fibroblast population as a primary integrator of hypertrophic stimuli in the heart, and suggest that FGF-2 is a crucial mediator of cardiac hypertrophy via autocrine/paracrine actions on cardiac cells. PMID:11748268

  10. Functional evolution of cardiac microRNAs in heart development and functions.

    PubMed

    Lin, Chen-Ching; Chang, Yao-Ming; Pan, Cheng-Tsung; Chen, Chien-Chang; Ling, Li; Tsao, Ku-Chi; Yang, Ruey-Bing; Li, Wen-Hsiung

    2014-10-01

    MicroRNAs (miRNAs) are a class of endogenous small noncoding RNAs that regulate gene expression either by degrading target mRNAs or by suppressing protein translation. miRNAs have been found to be involved in many biological processes, such as development, differentiation, and growth. However, the evolution of miRNA regulatory functions and networks has not been well studied. In this study, we conducted a cross-species analysis to study the evolution of cardiac miRNAs and their regulatory functions and networks. We found that conserved cardiac miRNA target genes have maintained highly conserved cardiac functions. Additionally, most of cardiac miRNA target genes in human with annotations of cardiac functions evolved from the corresponding homologous targets, which are also involved in heart development-related functions. On the basis of these results, we investigated the functional evolution of cardiac miRNAs and presented a functional evolutionary map. From this map, we identified the evolutionary time at which the cardiac miRNAs became involved in heart development or function and found that the biological processes of heart development evolved earlier than those of heart functions, for example, heart contraction/relaxation or cardiac hypertrophy. Our study of the evolution of the cardiac miRNA regulatory networks revealed the emergence of new regulatory functional branches during evolution. Furthermore, we discovered that early evolved cardiac miRNA target genes tend to participate in the early stages of heart development. This study sheds light on the evolution of developmental features of genes regulated by cardiac miRNAs.

  11. Registration-based segmentation of murine 4D cardiac micro-CT data using symmetric normalization

    PubMed Central

    Clark, Darin; Badea, Alexandra; Liu, Yilin; Johnson, G. Allan; Badea, Cristian T.

    2013-01-01

    Micro-CT can play an important role in preclinical studies of cardiovascular disease because of its high spatial and temporal resolution. Quantitative analysis of 4D cardiac images requires segmentation of the cardiac chambers at each time point, an extremely time consuming process if done manually. To improve throughput this study proposes a pipeline for registration-based segmentation and functional analysis of 4D cardiac micro-CT data in the mouse. Following optimization and validation using simulations, the pipeline was applied to in vivo cardiac micro-CT data corresponding to 10 cardiac phases acquired in C57BL/6 mice (n = 5). After edge-preserving smoothing with a novel adaptation of 4D bilateral filtration, one phase within each cardiac sequence was manually segmented. Deformable registration was used to propagate these labels to all other cardiac phases for segmentation. The volumes of each cardiac chamber were calculated and used to derive stroke volume, ejection fraction, cardiac output, and cardiac index. Dice coefficients and volume accuracies were used to compare manual segmentations of two additional phases with their corresponding propagated labels. Both measures were, on average, >0.90 for the left ventricle and >0.80 for the myocardium, the right ventricle, and the right atrium, consistent with trends in inter- and intra-segmenter variability. Segmentation of the left atrium was less reliable. On average, the functional metrics of interest were underestimated by 6.76% or more due to systematic label propagation errors around atrioventricular valves; however, execution of the pipeline was 80% faster than performing analogous manual segmentation of each phase. PMID:22971564

  12. 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.

  13. Cardiac ion channels in health and disease.

    PubMed

    Amin, Ahmad S; Tan, Hanno L; Wilde, Arthur A M

    2010-01-01

    Cardiac electrical activity depends on the coordinated propagation of excitatory stimuli through the heart and, as a consequence, the generation of action potentials in individual cardiomyocytes. Action potential formation results from the opening and closing (gating) of ion channels that are expressed within the sarcolemma of cardiomyocytes. Ion channels possess distinct genetic, molecular, pharmacologic, and gating properties and exhibit dissimilar expression levels within different cardiac regions. By gating, ion channels permit ion currents across the sarcolemma, thereby creating the different phases of the action potential (e.g., resting phase, depolarization, repolarization). The importance of ion channels in maintaining normal heart rhythm is reflected by the increased incidence of arrhythmias in inherited diseases that are linked to mutations in genes encoding ion channels or their accessory proteins and in acquired diseases that are associated with changes in ion channel expression levels or gating properties. This review discusses ion channels that contribute to action potential formation in healthy hearts and their role in inherited and acquired diseases. PMID:19875343

  14. 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

  15. 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.

  16. 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

  17. 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

  18. 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

    2015-03-20

    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.

  19. 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.

  20. [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.

  1. [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

  2. 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

  3. Acupuncture therapy related cardiac injury.

    PubMed

    Li, Xue-feng; Wang, Xian

    2013-12-01

    Cardiac injury is the most serious adverse event in acupuncture therapy. The causes include needling chest points near the heart, the cardiac enlargement and pericardial effusion that will enlarge the projected area on the body surface and make the proper depth of needling shorter, and the incorrect needling method of the points. Therefore, acupuncture practitioners must be familiar with the points of the heart projected area on the chest and the correct needling methods in order to reduce the risk of acupuncture therapy related cardiac injury.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Managing high-output stomas: module 3 of 3.

    PubMed

    Slater, Rebecca; Gabe, Simon

    Enterocutaneous fistulae (ECF) and high-output stomas are challenging to manage, owing to the large volume of loss that may result in severe dehydration, electrolyte imbalances, malnutrition and sepsis. It is imperative that this group of patients receive adequate nutrition, as malnutrition and sepsis are the leading cause of death. Treatment is complex and based on various situations, treatment can be medical/conservative management or surgical. Depending on the site of the fistula and the length of residual intestine contributing as the cause of a high output stoma with the nutritional status of the patient, clinicians have to decide whether parenteral nutrition (PN) or enteral nutrition (EN) should be established. As previously discussed in module 1 and 2 (Gabe, 2013; Gabe and Slater, 2013) the theme of nutritional management and appliance/accessory selection to manage patients with ECF and high output stomas was outlined. The aim of providing an understanding of the nutritional needs and the practicalities of maintaining appliance adherence, and in turn, a reduction in the breakdown of the peri-stomal skin was described. Module 3 aims to provide understanding for the reader that may encounter patients undergoing surgery for the management of their ECF or high-output stoma. Lastly it was felt necessary to discuss the subject of intestinal transplantation. This complex surgical option is not available to all patients with intestinal failure and only undertaken at a couple of recognised centres. The process of referring patients that are deemed suitable for intestinal transplantation will be addressed and what the surgery entails with long-term outcomes and the quality of life for the patient.

  9. 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

  10. Programmed evolution for optimization of orthogonal metabolic output in bacteria.

    PubMed

    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

  11. Programmed evolution for optimization of orthogonal metabolic output in bacteria.

    PubMed

    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

  12. Cardiac performance correlates of relative heart ventricle mass in amphibians.

    PubMed

    Kluthe, Gregory J; Hillman, Stanley S

    2013-08-01

    This study used an in situ heart preparation to analyze the power output and stroke work of spontaneously beating hearts of four anurans (Rhinella marina, Lithobates catesbeianus, Xenopus laevis, Pyxicephalus edulis) and three urodeles (Necturus maculosus, Ambystoma tigrinum, Amphiuma tridactylum) that span a representative range of relative ventricle mass (RVM) found in amphibians. Previous research has documented that RVM correlates with dehydration tolerance and maximal aerobic capacity in amphibians. The power output (mW g(-1) ventricle mass) and stroke work (mJ g(-1) ventricle muscle mass) were independent of RVM and were indistinguishable from previously published results for fish and reptiles. RVM was significantly correlated with maximum power output (P max, mW kg(-1) body mass), stroke volume, cardiac output, afterload pressure (P O) at P max, and preload pressure (P I) at P max. P I at P max and P O at P max also correlated very closely with each other. The increases in both P I and P O at maximal power outputs in large hearts suggest that concomitant increases in blood volume and/or increased modulation of vascular compliance either anatomically or via sympathetic tone on the venous vasculature would be necessary to achieve P max in vivo. Hypotheses for variation in RVM and its concomitant increased P max in amphibians are developed.

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

    EPA Science Inventory

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

  14. 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.

  15. 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

  16. Recent developments in cardiac pacing.

    PubMed

    Rodak, D J

    1995-10-01

    Indications for cardiac pacing continue to expand. Pacing to improve functional capacity, which is now common, relies on careful patient selection and technical improvements, such as complex software algorithms and diagnostic capabilities.

  17. Robot-Assisted Cardiac Surgery

    PubMed Central

    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

  18. Cardiac Rehabilitation: Then and Now.

    ERIC Educational Resources Information Center

    Wilson, Philip K.

    1988-01-01

    As more and more patients survive a coronary event, the need for cardiac rehabilitation will increase. The author reviews the history and current status of this field and predicts what lies ahead. (JD)

  19. 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

  20. MedlinePlus: Cardiac Rehabilitation

    MedlinePlus

    ... available Research Clinical Trials Journal Articles Resources Reference Desk Find an Expert For You Patient Handouts Summary Cardiac rehabilitation (rehab) is a medically supervised program to help people who have A heart attack Angioplasty or ...