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1

High output cardiac failure  

Microsoft Academic Search

Opinion statement  Congestive heart failure describes a syndrome with complex and variable symptoms and signs, including dyspnea, increased fatigability,\\u000a tachypnea, tachycardia, pulmonary rales, and peripheral edema. Although this syndrome usually is associated with low cardiac\\u000a output, it may occur in a number of so-called high output states, when the cardiac output is normal or greater than normal.\\u000a A high output state

Inder S. Anand; Viorel G. Florea

2001-01-01

2

The Determinants of Cardiac Output  

NSDL National Science Digital Library

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

Anderson, Robert M.

3

Predictors of low cardiac output syndrome after coronary artery bypass  

Microsoft Academic Search

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

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

1996-01-01

4

Mathematics and the Heart: Understanding Cardiac Output  

ERIC Educational Resources Information Center

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

Champanerkar, Jyoti

2013-01-01

5

Determination of cardiac output by Doppler echocardiography  

Microsoft Academic Search

Cardiac output determined by Doppler echocardiography was compared with that determined by thermodilution at rest and during dobutamine infusion in 10 patients (group A) and by the Fick method at rest in 11 patients (group B). All patients had angina pectoris without valvular heart disease. Maximum spatial blood velocity and cross sectional aortic area were estimated by the Doppler technique

H Ihlen; J P Amlie; J Dale; K Forfang; S Nitter-Hauge; J E Otterstad; S Simonsen; E Myhre

1984-01-01

6

USCOM (Ultrasonic Cardiac Output Monitors) lacks agreement with thermodilution cardiac output and transoesophageal echocardiography valve measurements.  

PubMed

The USCOM (Ultrasonic Cardiac Output Monitors) device is a non-invasive cardiac output monitor, which utilises transaortic or transpulmonary Doppler flow tracing and valve area estimated using patient height to determine cardiac output. We evaluated USCOM against thermodilution cardiac outputs and transoesophageal echocardiography valve area measurements in 22 ASA PS4 cardiac surgical patients. Data collection commenced following pulmonary artery catheter insertion, with cardiac output measurements repeated after sternotomy closure. Failure to obtain transaortic Doppler readings using USCOM occurred in 5% of planned measurements. USCOM transaortic analysis was not planned for 11 patients with known aortic disease. Bias at the aortic window (n = 20) was -0.79 l/min with limits of agreement from -3.66 to 2.08 l/min. At the pulmonary window, failure to obtain Doppler readings occurred in 24% of planned measurements. Bias at the pulmonary window (n = 36) was -0.17 l/min with limits of agreement from -3.30 to 2.97 l/min. The USCOM estimates of valve area based on height showed poor correlation with the echocardiographic measurements of aortic and pulmonary valves (r = 0.57 and r = 0.17, respectively). It was concluded that USCOM showed poor agreement with thermodilution. The estimated valve area was identified as one source of error. PMID:18084981

Van den Oever, H L A; Murphy, E J; Christie-Taylor, G A

2007-12-01

7

Cardiac output changes during hyperbaric hyperoxia  

Microsoft Academic Search

Objectives: Increased ambient pressure and oxygen partial pressure (pO2) influence cardiovascular regulation during diving and caisson work. We measured the cardiac output (Q?) in subjects who practiced moderate work at a usual diving depth of 30?m. Methods: In 23 healthy male Navy divers who performed steady state bicycle exercises (100?W workload) in a hyperbaric chamber Q? was measured by a

Birger Neubauer; Kay Tetzlaff; Carl-Michael Staschen; Eyke Bettinghausen

2001-01-01

8

Clinical review: Positive end-expiratory pressure and cardiac output  

PubMed Central

In patients with acute lung injury, high levels of positive end-expiratory pressure (PEEP) may be necessary to maintain or restore oxygenation, despite the fact that 'aggressive' mechanical ventilation can markedly affect cardiac function in a complex and often unpredictable fashion. As heart rate usually does not change with PEEP, the entire fall in cardiac output is a consequence of a reduction in left ventricular stroke volume (SV). PEEP-induced changes in cardiac output are analyzed, therefore, in terms of changes in SV and its determinants (preload, afterload, contractility and ventricular compliance). Mechanical ventilation with PEEP, like any other active or passive ventilatory maneuver, primarily affects cardiac function by changing lung volume and intrathoracic pressure. In order to describe the direct cardiocirculatory consequences of respiratory failure necessitating mechanical ventilation and PEEP, this review will focus on the effects of changes in lung volume, factors controlling venous return, the diastolic interactions between the ventricles and the effects of intrathoracic pressure on cardiac function, specifically left ventricular function. Finally, the hemodynamic consequences of PEEP in patients with heart failure, chronic obstructive pulmonary disease and acute respiratory distress syndrome are discussed. PMID:16356246

Luecke, Thomas; Pelosi, Paolo

2005-01-01

9

Doppler measurement of cardiac output during cardiopulmonary resuscitation  

Microsoft Academic Search

OBJECTIVE: To estimate the cardiac output produced by external cardiac compression during standard cardiopulmonary resuscitation performed by two groups of operators with different levels of experience and training. METHODS: Cardiac output was measured by Doppler aortovelography. All patients included in the study had necropsy examinations. Only patients without evidence of pulmonary embolism, myocardial rupture, aortic valve disease, or acute depletion

D I Fodden; A C Crosby; K S Channer

1996-01-01

10

Methods and apparatus for determining cardiac output  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

11

Newer methods of cardiac output monitoring.  

PubMed

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

Mehta, Yatin; Arora, Dheeraj

2014-09-26

12

Newer methods of cardiac output monitoring  

PubMed Central

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

Mehta, Yatin; Arora, Dheeraj

2014-01-01

13

Rapid Cardiac-Output Measurement With Ungated Spiral Phase Contrast  

E-print Network

Rapid Cardiac-Output Measurement With Ungated Spiral Phase Contrast Jong B. Park,1* Bob S. Hu,1) method was used to measure cardiac output (CO) rapidly and conveniently. The USPC method, which and TRT measurements from all normal volun- teers agreed. In a patient with patent ductus arteriosus (PDA

Southern California, University of

14

Cardiac output estimation using arterial blood pressure waveforms  

E-print Network

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

Sun, James Xin

2006-01-01

15

The cardiac output from blood pressure algorithms trial  

E-print Network

Objective: The value of different algorithms that estimate cardiac output (CO) by analysis of a peripheral arterial blood pressure (ABP) waveform has not been definitively identified. In this investigation, we developed a ...

Sun, James X.

16

Cardiac output estimation using pulmonary mechanics in mechanically ventilated patients  

Microsoft Academic Search

The application of positive end expiratory pressure (PEEP) in mechanically ventilated (MV) patients with acute respiratory distress syndrome (ARDS) decreases cardiac output (CO). Accurate measurement of CO is highly invasive and is not ideal for all MV critically ill patients. However, the link between the PEEP used in MV, and CO provides an opportunity to assess CO via MV therapy

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

2010-01-01

17

Evaluation of noninvasive cardiac output methods during exercise  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

18

The relationship between cardiac output and dynamic cerebral autoregulation in humans  

PubMed Central

Cerebral autoregulation adjusts cerebrovascular resistance in the face of changing perfusion pressures to maintain relatively constant flow. Results from several studies suggest that cardiac output may also play a role. We tested the hypothesis that cerebral blood flow would autoregulate independent of changes in cardiac output. Transient systemic hypotension was induced by thigh-cuff deflation in 19 healthy volunteers (7 women) in both supine and seated positions. Mean arterial pressure (Finapres), cerebral blood flow (transcranial Doppler) in the anterior (ACA) and middle cerebral artery (MCA), beat-by-beat cardiac output (echocardiography), and end-tidal Pco2 were measured. Autoregulation was assessed using the autoregulatory index (ARI) defined by Tiecks et al. (Tiecks FP, Lam AM, Aaslid R, Newell DW. Stroke 26: 1014–1019, 1995). Cerebral autoregulation was better in the supine position in both the ACA [supine ARI: 5.0 ± 0.21 (mean ± SE), seated ARI: 3.9 ± 0.4, P = 0.01] and MCA (supine ARI: 5.0 ± 0.2, seated ARI: 3.8 ± 0.3, P = 0.004). In contrast, cardiac output responses were not different between positions and did not correlate with cerebral blood flow ARIs. In addition, women had better autoregulation in the ACA (P = 0.046), but not the MCA, despite having the same cardiac output response. These data demonstrate cardiac output does not appear to affect the dynamic cerebral autoregulatory response to sudden hypotension in healthy controls, regardless of posture. These results also highlight the importance of considering sex when studying cerebral autoregulation. PMID:20689094

Deegan, B. M.; Devine, E. R.; Geraghty, M. C.; Jones, E.; ÓLaighin, G.

2010-01-01

19

Comparison of thermodilution bolus cardiac output and Doppler cardiac output in the early post-cardiopulmonary bypass period  

Microsoft Academic Search

Objective: To evaluate the accuracy of measuring cardiac output (CO) in the early post-cardiopulmonary bypass (CPB) period by comparing thermodilution with Doppler methods. Design: Prospective and blinded human trial. Setting: Academic medical center. Participants: Thirty adult patients undergoing elective coronary artery bypass graft surgery. Measurements and Main Results: Thermodilution CO (TCO) was obtained in triplicate. Doppler CO (DCO) in triplicate

Xiaoqin Zhao; John S. Mashikian; Pete Panzica; Adam Lerner; Kyung W. Park; Mark E. Comunale

2003-01-01

20

Measurement of cardiac output from dynamic pulmonary circulation time CT  

SciTech Connect

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.

Yee, Seonghwan, E-mail: Seonghwan.Yee@Beaumont.edu [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States)] [Department of Radiation Oncology, Beaumont Health System, Royal Oak, Michigan 48073 (United States); Scalzetti, Ernest M. [Department of Radiology, SUNY Upstate Medical University, Syracuse, New York 13210 (United States)] [Department of Radiology, SUNY Upstate Medical University, Syracuse, New York 13210 (United States)

2014-06-15

21

Clinical and haemodynamic effects of milrinone in the treatment of low cardiac output after cardiac surgery.  

PubMed

We have studied the haemodynamic effects of i.v. milrinone, a new phosphodiesterase inhibitor, in patients with low cardiac output after cardiac surgery. Thirty-five patients with a cardiac index (Cl) less than 2.5 litre min-1 m-2 and a pulmonary capillary wedge pressure (PCWP) greater than 8 mm Hg were given a loading dose of milrinone 50 micrograms kg-1 followed by an infusion at one of three rates: 0.375 micrograms kg-1 min-1, 0.5 micrograms kg-1 min-1 or 0.75 micrograms kg-1 min-1 for 12 h. After 1 h there were increases in Cl (35%) (P less than 0.001), heart rate (13%) (P less than 0.01) and stroke volume index (19%) (P less than 0.005). There were decreases in mean arterial pressure (12%) (P less than 0.01), systemic vascular resistance (35%) (P less than 0.001) and PCWP (24%) (P less than 0.05). Pulmonary vascular resistance was unchanged or reduced and left ventricular stroke work index was unchanged or increased. The haemodynamic improvements were sustained throughout the infusion period. Milrinone was tolerated well: three patients developed tachycardia greater than 125 beat min-1, one patient developed atrial fibrillation and one patient had a short run of atrial bigemini. We conclude that milrinone is a useful agent in the treatment of patients with a reduced cardiac output after cardiac surgery. PMID:1751273

Wright, E M; Sherry, K M

1991-11-01

22

Significant role of estrogen in maintaining cardiac mitochondrial functions.  

PubMed

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

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

2015-03-01

23

Continuous cardiac output monitoring by peripheral blood pressure waveform analysis.  

PubMed

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

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

2006-03-01

24

Rapid Cardiac-Output Measurement with Ungated Spiral Phase-Contrast J. B. Park1  

E-print Network

Rapid Cardiac-Output Measurement with Ungated Spiral Phase-Contrast J. B. Park1 , B. S. Hu1,2 , S Engineering, University of Southern California, Los Angeles, CA, United States Introduction: Cardiac output (CO) can be a key indicator for assessing patients with cardiovascular diseases and can

Southern California, University of

25

The effects of chronic prostacyclin therapy on cardiac output and symptoms in primary pulmonary hypertension  

Microsoft Academic Search

OBJECTIVESThis study evaluated the response to prostacyclin dose reduction in patients with primary pulmonary hypertension (PPH) who developed high cardiac outputs.BACKGROUNDPatients on prostacyclin require chronic upward dose titration to overcome tolerance to the medication. No upper limit of effective dose has been described.METHODSWe studied 12 patients with PPH treated with chronic prostacyclin therapy who presented in high cardiac output states.

Stuart Rich; Vallerie V McLaughlin

1999-01-01

26

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

Microsoft Academic Search

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

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

1988-01-01

27

Feasibility and variability of six methods for the echocardiographic and Doppler determination of cardiac output  

Microsoft Academic Search

The feasibility and the intrinsic variability of six different methods of echocardiographic and Doppler flow determination of cardiac output were analysed in 34 healthy volunteers. Four were excluded because of poor quality echocardiograms. The mean (range) age of the remaining 30 (12 women, 18 men) was 21 years (13-36 years). Cardiac output was calculated by six methods as a product

G L Nicolosi; E Pungercic; E Cervesato; D Pavan; L Modena; E Moro; V DallAglio; D Zanuttini

1988-01-01

28

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

E-print Network

Changes in cardiac output during swimming and aquatic hypoxia in the air-breathing Pacific tarpon T-breathing organ (ABO). We examined changes in cardiac output (Vb) associated with increases in air to recover in a swim flume at 27 °C after being instrumented with a Doppler flow probe around the ventral

Farrell, Anthony P.

29

Transoesophageal Doppler echocardiographic measurement of cardiac output by the mitral annulus method  

PubMed Central

Objective—To compare cardiac output measured by the transoesophageal Doppler and thermodilution techniques. Design—Prospective direct comparison of paired measurements by both techniques in each patient. Setting—Intensive care unit in a cardiovascular centre. Patients—65 patients after open heart surgery (mean (SD) age 53 (12) years). Interventions—Cardiac output was measured simultaneously by the transoesophageal Doppler and thermodilution techniques. Cardiac output was measured again after a mechanical intervention or volume loading. Results—The limits of agreement were ?2·53 to +0·83 1·min?1 for cardiac output measured by the Doppler and thermodilution techniques. This suggests that the Doppler method alone would not be suitable for clinical use. The second measurement of cardiac output by thermodilution was compared with cardiac output estimated from the first and second Doppler measurements and the first thermodilution measurement. The limits of agreement (?0·55 to +0·51 1·min?1) were good enough for clinical use. Conclusions—After cardiac output had been measured simultaneously by both the Doppler and thermodilution techniques, subsequent transoesophageal Doppler alone gave a clinically useful measurement of cardiac output. PMID:1467040

Shimamoto, Hiroyuki; Kito, Hiroyuki; Kawazoe, Kohei; Fujita, Tsuyoshi; Shimamoto, Yoriko

1992-01-01

30

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

NASA Astrophysics Data System (ADS)

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

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

2008-06-01

31

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

PubMed Central

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

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

2014-01-01

32

Cardiac output during exercise: a comparison of four methods.  

PubMed

Several techniques assessing cardiac output (Q) during exercise are available. The extent to which the measurements obtained from each respective technique compares to one another, however, is unclear. We quantified Q simultaneously using four methods: the Fick method with blood obtained from the right atrium (Q(Fick-M)), Innocor (inert gas rebreathing; Q(Inn)), Physioflow (impedance cardiography; Q(Phys)), and Nexfin (pulse contour analysis; Q(Pulse)) in 12 male subjects during incremental cycling exercise to exhaustion in normoxia and hypoxia (FiO2 ?= 12%). While all four methods reported a progressive increase in Q with exercise intensity, the slopes of the Q/oxygen uptake (VO2) relationship differed by up to 50% between methods in both normoxia [4.9 ± 0.3, 3.9 ± 0.2, 6.0 ± 0.4, 4.8 ± 0.2 L/min per L/min (mean ± SE) for Q(Fick-M), Q(Inn), QP hys and Q(Pulse), respectively; P = 0.001] and hypoxia (7.2 ± 0.7, 4.9 ± 0.5, 6.4 ± 0.8 and 5.1 ± 0.4 L/min per L/min; P = 0.04). In hypoxia, the increase in the Q/VO2 slope was not detected by Nexfin. In normoxia, Q increases by 5-6 L/min per L/min increase in VO2, which is within the 95% confidence interval of the Q/VO2 slopes determined by the modified Fick method, Physioflow, and Nexfin apparatus while Innocor provided a lower value, potentially reflecting recirculation of the test gas into the pulmonary circulation. Thus, determination of Q during exercise depends significantly on the applied method. PMID:24646113

Siebenmann, C; Rasmussen, P; Sørensen, H; Zaar, M; Hvidtfeldt, M; Pichon, A; Secher, N H; Lundby, C

2015-02-01

33

Comparison of bedside measurement of cardiac output with the thermodilution method and the Fick method in mechanically ventilated patients  

Microsoft Academic Search

INTRODUCTION: Bedside cardiac output determination is a common preoccupation in the critically ill. All available methods have drawbacks. We wished to re-examine the agreement between cardiac output determined using the thermodilution method (QTTHERM) and cardiac output determined using the metabolic (Fick) method (QTFICK) in patients with extremely severe states, all the more so in the context of changing practices in

Jésus Gonzalez; Christian Delafosse; Muriel Fartoukh; André Capderou; Christian Straus; Marc Zelter; Jean-Philippe Derenne; Thomas Similowski

2003-01-01

34

Cardiac output and stroke volume estimation using a hybrid of three models  

E-print Network

Cardiac output (CO) and stroke volume (SV) are the key hemodynamic parameters to be monitored and assessed in ambulatory and critically ill patients. The purpose of this study was to introduce and validate a new algorithm ...

Arai, Tatsuya

35

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

E-print Network

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

Chen, Tiffany

2009-01-01

36

Calculating arterial pressure-based cardiac output using a novel measurement and analysis method.  

PubMed

Work on applying physical and physiological principles for determining cardiac output by analysis of pressure measurements has been pursued for decades. Reference measurements for this kind of cardiac output analysis rely on the pulmonary artery catheter (PAC), considered the clinical gold standard for cardiac output monitoring. Recent advances in signal processing, as well as applied information on the relationships that enable arterial pulse pressure to be used to determine stroke volume, have led to the development of a novel system that can continuously measure cardiac output from an arterial pressure waveform that does not require an external calibration reference method. There are significant challenges in applying statistical- and signal-processing practices to the analysis of complex physiological waveforms. This paper reviews the historical basis for measuring flow from the analysis of pressure in a vessel, establishes the physiological and mathematical basis for this new system and describes its performance under various physiological conditions. PMID:17992808

Pratt, Benjamin; Roteliuk, Luchy; Hatib, Feras; Frazier, John; Wallen, Roy D

2007-01-01

37

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

Microsoft Academic Search

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

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

2001-01-01

38

In vitro, in vivo and numerical assessment of the working principle of the truCCOMS continuous cardiac output catheter system.  

PubMed

The truCCOMS cardiac output monitor system provides a continuous and instantaneous measurement of cardiac output, derived from the amount of energy required for heating a filament to maintain a fixed 2 degrees C blood temperature difference between two thermistors located distally on a pulmonary artery catheter. Clinical studies, however, reported relatively poor accuracy of the cardiac output estimation, possibly due to linearly assumed power-cardiac output relationship used for calibration of the catheters. We experimentally studied the shape of the truCCOMS calibration relationship (i) in a hydraulic bench model of the right heart and (ii) in vivo intact animal model. The results showed a nonlinear relationship between the power input into the heating element and the cardiac output; which could satisfactorily be described with an exponential relationship. Comparison of the performance of the same catheters in vitro and in vivo showed that the in vitro determined calibration relationship should not be used for in vivo measurements. Finally, we also simulated the working principle of the catheter using a simplified numerical model of the blood flow and heat transfer around the catheter. The computed results also suggested a pronounced nonlinear relationship between power and cardiac output in pulsatile conditions. We conclude that the observed over- and underestimation of high- and low flows, respectively, by the current truCCOMS system is likely to arise from its linear calibration relationship. An appropriate calibration scheme accounting for the intrinsic nonlinear power-cardiac output relationship and the difference between in vitro and in vivo conditions should improve the clinical performance of the system. PMID:19767233

Claessens, T; Verwilst, P; Missant, C; Claus, P; Verdonck, P; Wouters, P; Segers, P

2009-12-01

39

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

PubMed

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. PMID:15683494

Riedlbauchová, Lucie; Kautzner, Josef; Frídl, Petr

2005-01-01

40

Doppler determination of cardiac output in infants and children: Comparison with simultaneous thermodilution  

Microsoft Academic Search

Summary  Ten children, aged six weeks to 13 years, without intracardiac shunts or lesions that could cause turbulent flow in the ascending\\u000a aorta or aortic regurgitation, underwent cardiac catheterization, including cardiac output measurements by thermodilution.\\u000a Simultaneously with each of six consecutive thermodilution injections, mean and maximal blood velocities in the ascending\\u000a aorta were measured by pulsed Doppler echocardiography from the suprasternal

Mats Mellander; Karl-Göran Sabel; Kenneth Caidahl; Laszlo Solymar; Bengt Eriksson

1987-01-01

41

Epi-aortic Doppler measurement of cardiac output in univentricular connection  

PubMed Central

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

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

2009-01-01

42

Continuous cardiac output measurement - Aspects of Doppler frequency analysis  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

43

Modulation of cardiac output alters the mechanisms of the muscle metaboreflex pressor response  

PubMed Central

Muscle metaboreflex activation during submaximal dynamic exercise in normal subjects elicits a pressor response primarily due to increased cardiac output (CO). However, when the ability to increase CO is limited, such as in heart failure or during maximal exercise, the muscle metaboreflex-induced increases in arterial pressure occur via peripheral vasoconstriction. How the mechanisms of this pressor response are altered is unknown. We tested the hypothesis that this change in metaboreflex function is dependent on the level of CO. The muscle metaboreflex was activated in dogs during mild dynamic exercise (3.2 km/h) via a partial reduction of hindlimb blood flow. Muscle metaboreflex activation increased CO and arterial pressure, whereas vascular conductance of all areas other than the hindlimbs did not change. CO was then reduced to the same level observed during exercise before the muscle metaboreflex activation via partial occlusion of the inferior and superior vena cavae. Arterial pressure dropped rapidly with the reduction in CO but, subsequently, nearly completely recovered. With the removal of the muscle metaboreflex-induced rise in CO, substantial peripheral vasoconstriction occurred that maintained arterial pressure at the same levels as before CO reduction. Therefore, the muscle metaboreflex function is nearly instantaneously shifted from increased CO to increased vasoconstriction when the muscle metaboreflex-induced rise in CO is removed. We conclude that whether vasoconstriction occurs with muscle metaboreflex depends on whether CO rises. PMID:19897706

Ichinose, Masashi J.; Sala-Mercado, Javier A.; Coutsos, Matthew; Li, ZhenHua; Ichinose, Tomoko K.; Dawe, Elizabeth

2010-01-01

44

Impedance cardiography: a comparison of cardiac output vs waveform analysis for assessing left ventricular systolic dysfunction.  

PubMed

Early detection of asymptomatic left ventricular systolic dysfunction (LVSD) is beneficial in managing heart failure. Recent studies have cast doubt on the usefulness of cardiac output as an indicator of LVSD. In impedance cardiography (ICG), the dZ/dt waveform has a systolic wave called the E wave. This study looked at measurements of the amplitude and area of the E wave compared with ICG-derived cardiac output, stroke volume, cardiac index, and stroke index as methods of assessing LVSD. ICG data were obtained from patients (n=26) admitted to a coronary care unit. Clinical LVSD severity was stratified into 4 groups (none, mild, moderate, and severe) based on echocardiography data and standard clinical assessment by a cardiologist blinded to ICG data. Statistical analysis showed that the E wave amplitude and area were better indicators of the level of LVSD than cardiac output, stroke volume, cardiac index, or stroke index. ICG waveform analysis has potential as a simple point-of-care test for detecting LVSD in asymptomatic patients at high risk for developing heart failure and for monitoring LVSD in patients being treated for heart failure. PMID:17786090

DeMarzo, Arthur P; Kelly, Russell F; Calvin, James E

2007-01-01

45

Radioactive microsphere measurement of cardiac output and regional tissue blood flow in the sheep  

Microsoft Academic Search

Previous reports have shown that radioactive microspheres may be used to obtain quantiative measurements of regional tissue blood flow in a number of species. The present work has shown that this also applies to the conscious sheep, and further, that microspheres provide a simple, accurate and reliable method for the routine measurement of cardiac output. Assessment of blood flow through

J. R. S. Hales; Ian Clunies

1973-01-01

46

Comparison of bioimpedance and thermodilution methods for determining cardiac output: Experimental and clinical studies  

Microsoft Academic Search

The changes in electrical bioimpedance caused by the blood flow through a thoracic segment may be measured using a series of electrodes placed at opposing ends of this segment. Cardiac output (CO) is calculated by computer as the change in bioimpedance over time. This study was performed to determine the accuracy of bioimpedance CO (CObi) compared with standard thermodilution CO

Francis G. Spinale; H. David Reines; Fred A. Crawford

1995-01-01

47

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

Microsoft Academic Search

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

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

1993-01-01

48

Postural effect on cardiac output, oxygen uptake and lactate during cycle exercise of varying intensity  

Microsoft Academic Search

Owing to changes in cardiac output, blood volume distribution and the efficacy of the muscle pump, oxygen supply may differ during upright and supine cycle exercise. In the present study we measured, in parallel, circulatory (heart rate, stroke volume, blood pressure) and metabolic parameters (oxygen uptake, lactic acid concentration [1a]) during incremental-exercise tests and at constant power levels ranging from

Dieter Leyk; Dieter Eßfeld; Uwe Hoffmann; Hans-Georg Wunderlich; Klaus Baum; Jiirgen Stegemann

1994-01-01

49

Hemodynamic-Induced Changes in Aortic Valve Area: Implications for Doppler Cardiac Output Determinations  

Microsoft Academic Search

Monitoring cardiac output (CO) by transesophageal echocardiography involves measurements of ascend- ing aortic flow and an initial measurement of aortic valve area (AVA). Hemodynamic-induced changes in AVA are a potential source of error for this simplified method. Our goal was to quantify these changes in AVA and their effects on CO calculations. In 17 anesthe- tized patients, a dobutamine infusion

Pamela E. Gray; Albert C. Perrino

2001-01-01

50

Suprasternal Doppler Estimation of Cardiac Output: Standard Versus Sequential Combined Spinal Epidural Anesthesia for Cesarean Delivery  

Microsoft Academic Search

BACKGROUND: Sequential (Seq) combined spinal epidural (CSE) may provide better cardiovascular stability than standard (Std) CSE for cesarean delivery. We com- pared the cardiovascular stability of both techniques using suprasternal Doppler. METHODS: Healthy women (n 40) scheduled for elective cesarean delivery were randomized into two groups; Std or Seq CSE. Serial measures of cardiac output indices, including minute distance, stroke

Johanna K. Bray; Roshan Fernando; Nisa P. Patel; Malachy O. Columb

2006-01-01

51

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

52

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

Microsoft Academic Search

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

R. M. BEVAN; P. J. BUTLER

53

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

Microsoft Academic Search

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

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

54

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

PubMed

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

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

2007-02-01

55

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

PubMed

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. PMID:19202234

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

2009-03-01

56

Long-term stable timing distribution of an ultrafast optical pulse train over multiple fiber links with polarization maintaining output  

E-print Network

The distribution of an ultrafast optical pulse train over multiple fiber links with long-term stable timing precision within 2 femtoseconds rms is accomplished by integrating a polarization maintaining output with 300 meter ...

Cox, Jonathan A.

57

The cardiac output response and the oxygen cost of increased work of breathing  

E-print Network

of MASTER OF SCIENCE December 1989 Major Subject: Physical Education THE CARDIAC OUTPUT RESPONSE AND THE OXYGEN COST OF INCREASED WORK OF BREATHING A Thesis by KEVIN MICHAEL KRAUSE Approved as to style and content by: J. Richard Coast (Chair... by Liljestrand (1918), by measuring oxygen consumption at rest and at a low level of hyperventilation. Since no non-ventilatory work was being performed, the subsequent increase in oxygen consumption was safely assumed to be utilized by the respiratory system...

Krause, Kevin Michael

1989-01-01

58

Validation and application of single breath cardiac output determinations in man  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

59

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

NASA Astrophysics Data System (ADS)

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.

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

1995-03-01

60

Cardiac output responses of primigravid women during exercise determined by the direct Fick technique.  

PubMed

We compared metabolic and cardiovascular responses to aerobic exercise with the direct Fick technique in women during and after pregnancy. Seven subjects were studied at 37 weeks' gestation and again 12 weeks postpartum. All were tested at rest and during four sequential exercise bouts consisting of 5 minutes at each of two cycle (50 and 75 W) and two treadmill (67 m x min-1 at 2.5 and 12% grade) protocols. Oxygen consumption (VO2) and heart rate were measured during the fifth minute of exercise. Arterial and mixed venous oxygen contents, obtained from catheters placed in the radial and pulmonary arteries, respectively, were used to calculate arterial-venous oxygen difference. Cardiac output and stroke volume were calculated from the Fick equation. Responses of VO2, cardiac output, and stroke volume were greater when exercise was performed at 37 weeks' gestation as compared with postpartum. In contrast, heart rate response (during cycling) and arterial-venous oxygen difference (during treadmill walking) were less when exercise was performed during pregnancy. Our results indicate that there is no compromise in maternal cardiac output during either cycle or treadmill exercise performed late in pregnancy as compared with postpartum conditions. PMID:2342744

Pivarnik, J M; Lee, W; Clark, S L; Cotton, D B; Spillman, H T; Miller, J F

1990-06-01

61

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

PubMed Central

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

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

2011-01-01

62

Porcine cardiac myocyte power output is increased after chronic exercise training.  

PubMed

Chronic exercise training increases the functional capacity of the heart, perhaps by increased myocyte contractile function, as has been observed in rodent exercise models. We examined whether cardiac myocyte function is enhanced after chronic exercise training in Yucatan miniature swine, whose heart characteristics are similar to humans. Animals were designated as either sedentary (Sed), i.e., cage confined, or exercise trained (Ex), i.e., underwent 16-20 wk of progressive treadmill training. Exercise training efficacy was shown with significantly increased heart weight-to-body weight ratios, skeletal muscle citrate synthase activity, and exercise tolerance. Force-velocity properties were measured by attaching skinned cardiac myocytes between a force transducer and position motor, and shortening velocities were measured over a range of loads during maximal Ca2+ activation. Myocytes (n = 9) from nine Ex pigs had comparable force production but a approximately 30% increase in peak power output compared with myocytes (n = 8) from eight Sed. Interestingly, Ex myofibrillar samples also had higher baseline PKA-induced phosphorylation levels of cardiac troponin I, which may contribute to the increase in power. Overall, these results suggest that enhanced power-generating capacity of porcine cardiac myofibrils contributes to improved cardiac function after chronic exercise training. PMID:16565350

Hinken, Aaron C; Korte, F Steven; McDonald, Kerry S

2006-07-01

63

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

PubMed Central

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

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

2012-01-01

64

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

PubMed Central

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

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

2014-01-01

65

Comparison and reliability of two non-invasive acetylene uptake techniques for the measurement of cardiac output  

Microsoft Academic Search

Comparison and reliability of two non-invasive acetylene uptake techniques for the measurement of cardiac output. Thirteen trained male cyclists performed CO2 rebreathing (CO2RB) at intensities from rest to 200 W, and open-circuit acetylene uptake (OpCirc) and single-breath acetylene uptake (SB) at intensities from rest to 300 W, with all procedures using 50 W increments. Oxygen consumption \\u000a cardiac output \\u000a and heart rate (HR), were

D. W. Dibski; D. J. Smith; R. Jensen; S. R. Norris; G. T. Ford

2005-01-01

66

Doppler-derived cardiac output in healthy newborn infants in relation to physiological patency of the ductus arteriosus  

Microsoft Academic Search

Summary Noninvasive Doppler-derived cardiac output was measured with the pulsed Doppler method in 22 healthy newborns during their first four days of life. Maximal blood flow velocity in the aorta was measured with the Doppler ultrasound method. The mean Doppler-derived cardiac output was 273±59 ml\\/min\\/kg. Ductal left-to-right shunting was also determined and then graded according to the flow in the

Hannu Hirsimäki; Pentti Kero; Olli Wanne; Risto Erkkola; Zita Makoi

1988-01-01

67

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

68

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

PubMed

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

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

2015-03-20

69

The measurement of cardiac output and related cardiovascular parameters in the Javelina (Tayassu tajacu)  

E-print Network

values 1'rom 39 observations were: mean arterial pressure - 139 mm. Hg; mean. right atrial pressure - 3. Z7 mm. Hg; mean left atrial pressure - 10. 6 mm. Hg; heart rate ? 1Zl beats/min. ; and mean blood velocity - 38. 4 cm. /sec. The cardiac output... was calculated to be Z778 ml. /min. and the stroke volume to be Z2. 9 ml. /beat. All animals died of an acute bacterial bronchopneumonia within 42 days following surgery. This infection was probably introduced via the catheters. The aortas of 4 of the 5...

Schilling, Paul Wesley

1968-01-01

70

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

E-print Network

Output in the Lobster JEFF B. THUMA AND SCOTT L. HOOPER Neuroscience Program, Department of Biological on a movement-related parameter of pyloric network output in the lobster. J Neurophysiol 89: 745­753, 2003; 10 of cardiac sac activity on the OSF of all pyloric neurons in the lobster, Panulirus interruptus

Hooper, Scott

71

Death due to high-output cardiac failure in fetal sacrococcygeal teratoma.  

PubMed

Fetal sacrococcygeal teratoma (SCT) is being recognized with increasing frequency. Placentomegaly and hydrops fetalis are preterminal events, and it has been suggested that fetal death may be due to high-output cardiac failure from arteriovenous shunting through the tumor. We had a chance to examine this hypothesis when a 21-week fetus presented with a huge sacrococcygeal teratoma. There were marked placentomegaly, cardiomegaly, hyperdynamic ventricles, and a pericardial effusion. Doppler studies showed tremendous flow through the SCT with extreme enlargement of the inferior vena cava, consistent with congestive heart failure from increased flow through the tumor. Hydrops developed, and the fetus was delivered because of placental abruption. This case provides supportive evidence that the teratoma acts as a large arteriovenous shunt, causing high-output cardiac failure. We have now collected 18 more cases of sacrococcygeal teratoma diagnosed in utero. Of the total 45 cases of fetal SCT, 9 had placentomegaly and/or fetal hydrops and all 9 fetuses died in utero or shortly after birth. We conclude that the only hope for survival in these severely affected fetuses is to reduce blood flow to the tumor before birth. PMID:2286911

Bond, S J; Harrison, M R; Schmidt, K G; Silverman, N H; Flake, A W; Slotnick, R N; Anderson, R L; Warsof, S L; Dyson, D C

1990-12-01

72

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

NASA Astrophysics Data System (ADS)

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

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

2005-02-01

73

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

Microsoft Academic Search

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

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

2009-01-01

74

Treatment of High Output Cardiac Failure by Flow-Adapted Hepatic Artery Banding (FHAB) in Patients with Hereditary Hemorrhagic Telangiectasia  

Microsoft Academic Search

Involvement of abdominal organs in Osler’s disease may lead to the development of hepatic arteriovenous shunts with a dilatation\\u000a of the hepatic artery. Right and subsequent global heart failure due to cardiac valvular insufficiency, pulmonary artery hypertension,\\u000a and hepatomegaly as well as increased cardiac output may result. This hyperdynamic hepatic blood flow can be reduced by ligature\\u000a or banding of

A. Koscielny; W. A. Willinek; A. Hirner; M. Wolff

2008-01-01

75

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

NASA Technical Reports Server (NTRS)

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

1980-01-01

76

Noninvasive photoacoustic measurement of the composite indicator dilution curve for cardiac output estimation  

PubMed Central

Recently, the measurement of indicator dilution curves using a photoacoustic (PA) technology was reported, which showed promising results on the noninvasive estimation of cardiac output (CO) that is an important hemodynamic parameter useful in various clinical situations. However, in clinical practice, measuring PA indicator dilution curves from an arterial blood vessel requires an ultrasound transducer array capable of focusing on the targeted artery. This causes several challenges on the clinical translation of the PA indicator dilution method, such as high sensor cost and complexity. In this paper, we theoretically derived that a composite PA indicator dilution curve simultaneously measured from both arterial and venous blood vessels can be used to estimate CO correctly. The ex-vivo and in-vivo experimental results with a flat ultrasound transducer verified the developed theory. We believe this new concept would overcome the main challenges on the clinical translation of the noninvasive PA indicator dilution technology. PMID:25780743

Kang, DongYel; Huang, Qiaojian; Li, Youzhi

2015-01-01

77

Reference values for total blood volume and cardiac output in humans  

SciTech Connect

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

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

1994-09-01

78

Elevations in energy expenditure are accompanied by increments in both ventilation and cardiac output to maintain  

E-print Network

aerobic metabolism. In contrast, it has been demonstrated that Burmese pythons (Python molurus) attain cascade. Possible limitations include the capacity of the ventilatory system to take up oxygen, the capacity of the cardiovascular system to deliver oxygen to muscle cells and the oxidative capacity

Bennett, Albert F.

79

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

PubMed

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

Horn, P; Ostadal, P; Ostadal, B

2014-10-15

80

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

PubMed Central

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

Kumar, Girish; Iyer, Parvathi U

2010-01-01

81

Increased systemic cardiac output improves arterial oxygen saturation in bidirectional cavopulmonary shunt.  

PubMed

The low arterial oxygen saturation (SaO2) after bidirectional cavopulmonary shunt (BCPS) predicts poor prognosis. The venous oxygen saturation of inferior vena cava (SivcO2), as well as the pulmonary blood flow/systemic blood flow ratio (Q p/Q s) affects the SaO2. The purpose of this study is to determine whether SivcO2 or Q p/Q s should be increased to achieve better outcomes after BCPS. Forty-eight patients undergoing BCPS were included. Data of patients' age and body weight, SivcO2, Q p/Q s, pulmonary artery (PA) pressure and resistance, PA area index, morphology of ventricle, atrioventricular valve regurgitation, and history of PA plasty were collected. Stepwise multiple logistic regression analyses were used to investigate which of the factors most affected the SaO2 after BCPS. There was a significant correlation between SivcO2 and SaO2 (r = 0.771, P < 0.00001). There was no strong correlation between Q p/Q s and SaO2 (r = 0.358, P < 0.05). Stepwise multiple logistic regression analyses revealed that both SivcO2 (r = 0.49, 95 % confidence interval (CI) 0.37-0.62, P < 0.0001) and Q p/Q s (r = 11.1, 95 % CI 3.3-18.9, P = 0.007) most affected SaO2 after BCPS. Since the SivcO2 has a stronger correlation than Q p/Q s with SaO2, despite the fact that both raising Q p/Q s and raising cardiac output can increase SaO2, raising cardiac output should be considered prior to Q p/Q s to raise the SaO2 after BCPS. PMID:24213974

Oka, Norihiko; Miyaji, Kagami; Kitamura, Tadashi; Itatani, Keiichi; Yoshii, Takeshi; Inoue, Nobuyuki; Fukunishi, Takuma; Shibata, Ko; Torii, Shinzo

2015-01-01

82

Noninvasive cardiac output measurement by inert gas rebreathing in suspected pulmonary hypertension.  

PubMed

The objective of this study was to evaluate inert gas rebreathing (IGR) reliability in cardiac output (CO) measurement compared with Fick method and thermodilution. IGR is a noninvasive method for CO measurement; CO by IGR is calculated as pulmonary blood flow plus intrapulmonary shunt. IGR may be ideal for follow-up of patients with pulmonary hypertension (PH), sparing the need of repeated invasive right-sided cardiac catheterization. Right-sided cardiac catheterization with CO measurement by thermodilution, Fick method, and IGR was performed in 125 patients with possible PH by echocardiography. Patients were grouped according to right-sided cardiac catheterization-measured mean pulmonary and wedge pressures: normal pulmonary arterial pressure (n = 20, mean pulmonary arterial pressure = 18 ± 3 mm Hg, pulmonary capillary wedge pressure = 11 ± 5 mm Hg), PH and normal pulmonary capillary wedge pressure (PH-NW, n = 37 mean pulmonary arterial pressure = 42 ± 13 mm Hg, pulmonary capillary wedge pressure = 11 ± 6 mm Hg), and PH and high pulmonary capillary wedge pressure (PH-HW, n = 68, mean pulmonary arterial pressure = 37 ± 9 mm Hg, pulmonary capillary wedge pressure = 24 ± 6 mm Hg). Thermodilution and Fick measurements were comparable. Fick and IGR agreement was observed in normal pulmonary arterial pressure (CO = 4.10 ± 1.14 and 4.08 ± 0.97 L/min, respectively), whereas IGR overestimated Fick in patients with PH-NW and those with PH-HW because of intrapulmonary shunting overestimation in hypoxemic patients. When patients with arterial oxygen saturation (SO2) ?90% were excluded, IGR and Fick agreement improved in PH-NW (CO = 4.90 ± 1.70 and 4.76 ± 1.35 L/min, respectively) and PH-HW (CO = 4.05 ± 1.04 and 4.10 ± 1.17 L/min, respectively). In hypoxemic patients, we estimated pulmonary shunt as Fick - pulmonary blood flow and calculated shunt as: -0.2423 × arterial SO2 + 21.373 L/min. In conclusion, IGR is reliable for CO measurement in patients with PH with arterial SO2 >90%. For patients with arterial SO2 ?90%, a new formula for shunt calculation is proposed. PMID:24315114

Farina, Stefania; Teruzzi, Giovanni; Cattadori, Gaia; Ferrari, Cristina; De Martini, Stefano; Bussotti, Maurizio; Calligaris, Giuseppe; Bartorelli, Antonio; Agostoni, Piergiuseppe

2014-02-01

83

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

PubMed Central

Muscle metaboreflex activation (MMA) during submaximal dynamic exercise in normal individuals increases mean arterial pressure (MAP) via increases in cardiac output (CO) with little peripheral vasoconstriction. The rise in CO occurs primarily via increases in heart rate (HR) with maintained or slightly increased stroke volume. When the reflex is sustained during recovery (postexercise muscle ischemia, PEMI), HR declines yet MAP remains elevated. The role of CO in mediating the pressor response during PEMI is controversial. In seven chronically instrumented canines, steady-state values with MMA during mild exercise (3.2 km/h) were observed by reducing hindlimb blood flow by ?60% for 3–5 min. MMA during exercise was followed by 60 s of PEMI. Control experiments consisted of normal exercise and recovery. MMA during exercise increased MAP, HR, and CO by 55.3 ± 4.9 mmHg, 42.5 ± 6.9 beats/min, and 2.5 ± 0.4 l/min, respectively. During sustained MMA via PEMI, MAP remained elevated and CO remained well above the normal recovery levels. Neither MMA during dynamic exercise nor during PEMI significantly affected peripheral vascular conductance. We conclude that the sustained increase in MAP during PEMI is driven by a sustained increase in CO not peripheral vasoconstriction. PMID:23427084

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

2013-01-01

84

Although it is well known that fish increase cardiac output (Q) during exercise to meet increased metabolic demands,  

E-print Network

, cardiac output, exercise, heart rate, mean circulatory filling pressure, prazosin, sea bass, stroke volume this increase. One view is that stroke volume (Vs) and, to a lesser extent, heart rate (fH) are responsible exercise will reduce the pressure gradient for venous return (flow) to the heart from the venous periphery

Farrell, Anthony P.

85

Combined use of phenoxybenzamine and dopamine for low cardiac output syndrome in children at withdrawal from cardiopulmonary bypass  

Microsoft Academic Search

The combined use of phenoxybenzamine and dopamine was applied in infants and children when it was difficult to come off cardiopulmonary bypass for low cardiac output. The rationale of this method is to prevent the alpha-adrenergic action of dopamine by phenoxybenzamine and to encourage the beta-adrenergic and direct specific action of dopamine. Dopamine was used in dosage of 10 to

M Kawamura; O Minamikawa; H Yokochi; S Maki; T Yasuda; Y Mizukawa

1980-01-01

86

Regional blood flow in chronic heart failure: the reason for the lack of correlation between patients' exercise tolerance and cardiac output?  

Microsoft Academic Search

BACKGROUND--In patients with chronic heart failure there is no relation between cardiac output and symptom limited exercise tolerance measured on a bicycle or treadmill. Furthermore, the increase in cardiac output in response to treatment may not be matched by a similar increase in exercise tolerance. More important in determining exercise capability is blood flow to skeletal muscle. This implies that

A F Muller; P Batin; S Evans; M Hawkins; A J Cowley

1992-01-01

87

Increased cardiac output elicits higher V?O2max in response to self-paced exercise.  

PubMed

Recently, a self-paced protocol demonstrated higher maximal oxygen uptake versus the traditional ramp protocol. The primary aim of the current study was to further explore potential differences in maximal oxygen uptake between the ramp and self-paced protocols using simultaneous measurement of cardiac output. Active men and women of various fitness levels (N = 30, mean age = 26.0 ± 5.0 years) completed 3 graded exercise tests separated by a minimum of 48 h. Participants initially completed progressive ramp exercise to exhaustion to determine maximal oxygen uptake followed by a verification test to confirm maximal oxygen uptake attainment. Over the next 2 sessions, they performed a self-paced and an additional ramp protocol. During exercise, gas exchange data were obtained using indirect calorimetry, and thoracic impedance was utilized to estimate hemodynamic function (stroke volume and cardiac output). One-way ANOVA with repeated measures was used to determine differences in maximal oxygen uptake and cardiac output between ramp and self-paced testing. Results demonstrated lower (p < 0.001) maximal oxygen uptake via the ramp (47.2 ± 10.2 mL·kg(-1)·min(-1)) versus the self-paced (50.2 ± 9.6 mL·kg(-1)·min(-1)) protocol, with no interaction (p = 0.06) seen for fitness level. Maximal heart rate and cardiac output (p = 0.02) were higher in the self-paced protocol versus ramp exercise. In conclusion, data show that the traditional ramp protocol may underestimate maximal oxygen uptake compared with a newly developed self-paced protocol, with a greater cardiac output potentially responsible for this outcome. PMID:25682980

Astorino, Todd Anthony; McMillan, David William; Edmunds, Ross Montgomery; Sanchez, Eduardo

2015-03-01

88

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

89

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

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

90

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

PubMed Central

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

Lujan, Heidi L.

2013-01-01

91

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

SciTech Connect

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

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

1984-01-01

92

Estimation of cardiac output from peripheral pressure waveforms using Laguerre model blind system identification.  

PubMed

We have developed a new technique, which may enable a more accurate, complete characterization of the circulatory system, including local or global hydrodynamic phenomena, using multiple measurements from several anatomic locations and/or multiple modalities. This technique, Laguerre model blind system identification (LMBSI), uses a Laguerre function series expansion to provide a compact but complete quantitative description of the distinct behavior of two or more circulatory waveforms. LMBSI identifies a set of five parameters per channel plus one common parameter that can be treated as a feature vector and used to predict cardiovascular parameters of interest. Standard statistical techniques can be used to extract information from that compact feature vector. In this paper, multiparameter regression is used to predict cardiac output, using two separate arterial pressure waveforms and the LMBSI algorithm. This serves as a proof-of-principle that two distinct circulatory waveforms, with LMBSI, can be used to characterize the circulatory system. In the future, this technique might be applied to noninvasive circulatory measurements. PMID:17271827

Reisner, A; McCombie, D; Asada, H

2004-01-01

93

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

PubMed

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

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

2013-12-01

94

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

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

95

Estimation of cardiac output and peripheral resistance using square-wave-approximated aortic flow signal  

PubMed Central

This paper presents a model-based approach to estimation of cardiac output (CO) and total peripheral resistance (TPR). In the proposed approach, the response of cardiovascular system (CVS), described by the windkessel model, is tuned to the measurements of systolic, diastolic and mean arterial blood pressures (BP) so as to yield optimal individual- and time-specific system time constant that is used to estimate CO and TPR. Unique aspects of the proposed approach are that it approximates the aortic flow as a train of square waves and that it also assumes pressure-dependent arterial compliance, as opposed to the traditional windkessel model in which aortic flow is approximated as a train of impulses and constant arterial compliance is assumed. It was shown that the proposed model encompasses the standard windkessel model as a limiting case, and that it also yields more realistic BP waveform response than the standard windkessel model. The proposed approach has potential to outperform its standard counterpart by treating systolic, diastolic, and mean BP as independent features in estimating CO and TPR, rather than solely resorting to pulse pressure as in the case of the standard windkessel model. Experimental results from in-vivo data collected from a number of animal subjects supports the viability of the proposed approach in that it could achieve approximately 29% and 24% reduction in CO and TPR errors when compared with its standard counterpart. PMID:22934049

Fazeli, Nima; Hahn, Jin-Oh

2012-01-01

96

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

PubMed

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

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

2015-03-16

97

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

PubMed Central

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

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

2015-01-01

98

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

PubMed Central

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

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

2013-01-01

99

Association of HeartMate II left ventricular assist device flow estimate with thermodilution cardiac output.  

PubMed

Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. However, LVAD flow estimate may be inaccurate in tracking true CO. We correlated LVAD (HeartMate II) flow with thermodilution CO during postoperative care (day 2-10 after implant) in 81 patients (5,616 paired measurements). Left ventricular assist device flow and CO correlated with a low correlation coefficient (r = 0.42). Left ventricular assist device readings were lower than CO measurements by approximately 0.36 L/min, trending for larger difference with higher values. Left ventricular assist device flow measurements showed less temporal variability compared with CO. Grouping for simultaneous measured blood pressure (BP < 60, 60-70, 70-80, 80-90, and ?90), the correlation of CO with LVAD flow differed (R = 0.42, 0.67, 0.48, 0.32, 0.32, respectively). Indicating better correlation when mean blood pressure is 60 to 70 mm Hg. Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation. PMID:25068779

Hasin, Tal; Huebner, Marianne; Li, Zhuo; Brown, Daniel; Stulak, John M; Boilson, Barry A; Joyce, Lyle; Pereira, Naveen L; Kushwaha, Sudhir S; Park, Soon J

2014-01-01

100

EFFECTS OF THYROXINE AND GROWTH HORMONE TREATMENT OF DAIRY COWS ON MILK YIELD, CARDIAC OUTPUT AND MAMMARY BLOOD FLOW 1  

Microsoft Academic Search

Four cows received thyroxine injections (T4; 20 mg\\/d) and three cows received growth hormone injec- tions (GH; 44 rag\\/d) for 4 d during successive 16-d experimental periods. Measurement was made of milk yield, protein yield, mammary tyrosine and phenylalanine uptake, blood plasma hormone concentrations, mammary blood flow and cardiac output. Milk yield increased by 25% with T4 and 21% with

S. R. Davis; R. J. Collier; J. P. McNamara; H. H. Head; W. Sussman

2010-01-01

101

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

Microsoft Academic Search

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

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

102

Non-invasive cardiac output evaluation during a maximal progressive exercise test, using a new impedance cardiograph device  

Microsoft Academic Search

.   One of the greatest challenges in exercise physiology is to develop a valid, reliable, non-invasive and affordable measurement\\u000a of cardiac output (CO). The purpose of this study was to evaluate the reproducibility and accuracy of a new impedance cardiograph\\u000a device, the Physio Flow, during a 1-min step incremental exercise test from rest to maximal peak effort. A group of

Ruddy Richard; Evelyne Lonsdorfer-Wolf; Anne Charloux; Stéphane Doutreleau; Martin Buchheit; Monique Oswald-Mammosser; Eliane Lampert; Bertrand Mettauer; Bernard Geny; Jean Lonsdorfer

2001-01-01

103

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

SciTech Connect

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.

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

1986-03-01

104

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

PubMed Central

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

Sabzi, Feridoun; Faraji, Reza

2015-01-01

105

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

SciTech Connect

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.

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

1985-05-01

106

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

PubMed Central

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

Farraj, Aimen K.

2013-01-01

107

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

PubMed

Background. The pulmonary artery catheter (PAC) is an accepted clinical method of measuring cardiac output (CO) despite no prior validation. The ultrasonic cardiac output monitor (USCOM) is a noninvasive alternative to PAC using Doppler ultrasound (CW). We compared PAC and USCOM CO measurements against a gold standard, the aortic flow probe (FP), in sheep at varying outputs. Methods. Ten conscious sheep, with implanted FPs, had measurements of CO by FP, USCOM, and PAC, at rest and during intervention with inotropes and vasopressors. Results. CO measurements by FP, PAC, and USCOM were 4.0 ± 1.2?L/min, 4.8 ± 1.5?L/min, and 4.0 ± 1.4?L/min, respectively, (n = 280, range 1.9?L/min to 11.7?L/min). Percentage bias and precision between FP and PAC, and FP and USCOM was -17 and 47%, and 1 and 36%, respectively. PAC under-measured Dobutamine-induced CO changes by 20% (relative 66%) compared with FP, while USCOM measures varied from FP by 3% (relative 10%). PAC reliably detected -30% but not +40% CO changes, as measured by receiver operating characteristic area under the curve (AUC), while USCOM reliably detected ±5% changes in CO (AUC > 0.70). Conclusions. PAC demonstrated poor accuracy and sensitivity as a measure of CO. USCOM provided equivalent measurements to FP across a sixfold range of outputs, reliably detecting ±5% changes. PMID:22649718

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

2012-01-01

108

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

PubMed Central

Background. The pulmonary artery catheter (PAC) is an accepted clinical method of measuring cardiac output (CO) despite no prior validation. The ultrasonic cardiac output monitor (USCOM) is a noninvasive alternative to PAC using Doppler ultrasound (CW). We compared PAC and USCOM CO measurements against a gold standard, the aortic flow probe (FP), in sheep at varying outputs. Methods. Ten conscious sheep, with implanted FPs, had measurements of CO by FP, USCOM, and PAC, at rest and during intervention with inotropes and vasopressors. Results. CO measurements by FP, PAC, and USCOM were 4.0 ± 1.2?L/min, 4.8 ± 1.5?L/min, and 4.0 ± 1.4?L/min, respectively, (n = 280, range 1.9?L/min to 11.7?L/min). Percentage bias and precision between FP and PAC, and FP and USCOM was ?17 and 47%, and 1 and 36%, respectively. PAC under-measured Dobutamine-induced CO changes by 20% (relative 66%) compared with FP, while USCOM measures varied from FP by 3% (relative 10%). PAC reliably detected ?30% but not +40% CO changes, as measured by receiver operating characteristic area under the curve (AUC), while USCOM reliably detected ±5% changes in CO (AUC > 0.70). Conclusions. PAC demonstrated poor accuracy and sensitivity as a measure of CO. USCOM provided equivalent measurements to FP across a sixfold range of outputs, reliably detecting ±5% changes. PMID:22649718

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

2012-01-01

109

Rb and p130 control cell cycle gene silencing to maintain the postmitotic phenotype in cardiac myocytes  

PubMed Central

The mammalian heart loses its regenerative potential soon after birth. Adult cardiac myocytes (ACMs) permanently exit the cell cycle, and E2F-dependent genes are stably silenced, although the underlying mechanism is unclear. Heterochromatin, which silences genes in many biological contexts, accumulates with cardiac differentiation. H3K9me3, a histone methylation characteristic of heterochromatin, also increases in ACMs and at E2F-dependent promoters. We hypothesize that genes relevant for cardiac proliferation are targeted to heterochromatin by retinoblastoma (Rb) family members interacting with E2F transcription factors and recruiting heterochromatin protein 1 (HP1) proteins. To test this hypothesis, we created cardiac-specific Rb and p130 inducible double knockout (IDKO) mice. IDKO ACMs showed a decrease in total heterochromatin, and cell cycle genes were derepressed, leading to proliferation of ACMs. Although Rb/p130 deficiency had no effect on total H3K9me3 levels, recruitment of HP1-? to promoters was lost. Depleting HP1-? up-regulated proliferation-promoting genes in ACMs. Thus, Rb and p130 have overlapping roles in maintaining the postmitotic state of ACMs through their interaction with HP1-? to direct heterochromatin formation and silencing of proliferation-promoting genes. PMID:21825075

Sdek, Patima; Zhao, Peng; Wang, Yaping; Huang, Chang-jiang; Ko, Christopher Y.; Butler, Peter C.; Weiss, James N.

2011-01-01

110

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

PubMed Central

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

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

1998-01-01

111

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

112

Cardiac output by Modelflow method from intra-arterial and fingertip pulse pressure profiles.  

PubMed

Modelflow, when applied to non-invasive fingertip pulse pressure recordings, is a poor predictor of cardiac output (Q, litre x min(-1)). The use of constants established from the aortic elastic characteristics, which differ from those of finger arteries, may introduce signal distortions, leading to errors in computing Q. We therefore hypothesized that peripheral recording of pulse pressure profiles undermines the measurement of Q with Modelflow, so we compared Modelflow beat-by-beat Q values obtained simultaneously non-invasively from the finger and invasively from the radial artery at rest and during exercise. Seven subjects (age, 24.0 +/- 2.9 years; weight, 81.2 +/- 12.6 kg) rested, then exercised at 50 and 100 W, carrying a catheter with a pressure head in the left radial artery and the photoplethysmographic cuff of a finger pressure device on the third and fourth fingers of the contralateral hand. Pulse pressure from both devices was recorded simultaneously and stored on a PC for subsequent Q computation. The mean values of systolic, diastolic and mean arterial pressure at rest and exercise steady state were significantly ( P < 0.05) lower from the finger than the intra-arterial catheter. The corresponding mean steady-state Q obtained from the finger (Qporta) was significantly ( P < 0.05) higher than that computed from the intra-arterial recordings (Qpia). The line relating beat-by-beat Qporta and Qpia was y =1.55 x -3.02 ( r2 = 0.640). The bias was 1.44 litre x min(-1) and the precision was 2.84 litre x min(-1). The slope of this line was significantly higher than 1, implying a systematic overestimate of Q by Qporta with respect to Qpia. Consistent with the tested hypothesis, these results demonstrate that pulse pressure profiles from the finger provide inaccurate absolute Q values with respect to the radial artery, and therefore cannot be used without correction with a calibration factor calculated previously by measuring Q with an independent method. PMID:14606952

Azabji Kenfack, Marcel; Lador, Federic; Licker, Marc; Moia, Christian; Tam, Enrico; Capelli, Carlo; Morel, Denis; Ferretti, Guido

2004-04-01

113

Blunted frequency-dependent upregulation of cardiac output is related to impaired relaxation in diastolic heart failure  

PubMed Central

Aims We tested the hypothesis that, in heart failure with normal ejection fraction (HFNEF), diastolic dysfunction is accentuated at increasing heart rates, and this contributes to impaired frequency-dependent augmentation of cardiac output. Methods and results In 17 patients with HFNEF (median age 69 years, 13 female) and seven age-matched control patients, systolic and diastolic function was analysed by pressure–volume loops at baseline heart rate and during atrial pacing to 100 and 120 min?1. At baseline, relaxation was prolonged and end-diastolic left ventricular stiffness was higher in HFNEF, whereas all parameters of systolic function were not different from control patients. This resulted in smaller end-diastolic volumes, higher end-diastolic pressure, and a lower stroke volume and cardiac index in HFNEF vs. control patients. During pacing, frequency-dependent upregulation of contractility indices (+dP/dtmax and Ees) occurred similarly in HFNEF and control patients, but frequency-dependent acceleration of relaxation (dP/dtmin) was blunted in HFNEF. In HFNEF, end-diastolic volume and stroke volume decreased with higher heart rates while both remained unchanged in control patients. Conclusion In HFNEF, frequency-dependent upregulation of cardiac output is blunted. This results from progressive volume unloading of the left ventricle due to limited relaxation reserve in combination with increased LV passive stiffness, despite preserved force–frequency relation. PMID:19720638

Wachter, Rolf; Schmidt-Schweda, Stephan; Westermann, Dirk; Post, Heiner; Edelmann, Frank; Kasner, Mario; Lüers, Claus; Steendijk, Paul; Hasenfuß, Gerd; Tschöpe, Carsten; Pieske, Burkert

2009-01-01

114

Mitofusin-2 Maintains Mitochondrial Structure and Contributes to Stress-Induced Permeability Transition in Cardiac Myocytes ? †  

PubMed Central

Mitofusin-2 (Mfn-2) is a dynamin-like protein that is involved in the rearrangement of the outer mitochondrial membrane. Research using various experimental systems has shown that Mfn-2 is a mediator of mitochondrial fusion, an evolutionarily conserved process responsible for the surveillance of mitochondrial homeostasis. Here, we find that cardiac myocyte mitochondria lacking Mfn-2 are pleiomorphic and have the propensity to become enlarged. Consistent with an underlying mild mitochondrial dysfunction, Mfn-2-deficient mice display modest cardiac hypertrophy accompanied by slight functional deterioration. The absence of Mfn-2 is associated with a marked delay in mitochondrial permeability transition downstream of Ca2+ stimulation or due to local generation of reactive oxygen species (ROS). Consequently, Mfn-2-deficient adult cardiomyocytes are protected from a number of cell death-inducing stimuli and Mfn-2 knockout hearts display better recovery following reperfusion injury. We conclude that in cardiac myocytes, Mfn-2 controls mitochondrial morphogenesis and serves to predispose cells to mitochondrial permeability transition and to trigger cell death. PMID:21245373

Papanicolaou, Kyriakos N.; Khairallah, Ramzi J.; Ngoh, Gladys A.; Chikando, Aristide; Luptak, Ivan; O'Shea, Karen M.; Riley, Dushon D.; Lugus, Jesse J.; Colucci, Wilson S.; Lederer, W. Jonathan; Stanley, William C.; Walsh, Kenneth

2011-01-01

115

Interleukin10, T-lymphocytes, and cardiac output in children after ventricular septal defect repair: a pilot study  

Microsoft Academic Search

Objective  To evaluate the acute inflammatory response and cardiac output in children \\u000aafter surgery for ventricular septal defect.Design and setting  Prospective, observational study in a level III multidisciplinary neonatal \\u000aand pediatric intensive care unit.Patients  Ten children undergoing open-heart surgery for ventricular septal defect.Interventions  All children received methylprednisolone (30?mg\\/kg) in cardiopulmonary \\u000abypass (CPB) prime.Measurements and results  Before and after cardiopulmonary bypass, plasma interleukin-10 and tumor \\u000anecrosis factor

Stefan Grosek; Janez Primozic; Alojz Ihan; Branka Wraber; Tone Gabrijelcic; Miro Kosin

2006-01-01

116

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

PubMed

The report describes a method of impedance cardiography using an improved estimate of thoracic volume. The formulas and their implementation in hardware and software are explained and new shortband electrodes are described which generate a good homogeneous thoracic field. Examples of stroke volume and cardiac output curves underline the capabilities of the monitoring system "Task Force Monitor". In several experiments, results are compared to thermodilution as well as to BioZ measurements: the new method excels in comparison with thermodilution and is comparable to the BioZ device. Compared to traditional electrodes, the new shortband electrodes are shown to provide better reproducibility. PMID:16131462

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

2006-11-01

117

Antenatal thrombosis of torcular herophili presenting with anemia, consumption coagulopathy and high-output cardiac failure in a preterm infant.  

PubMed

Dural sinus malformation occasionally results in the development of giant venous lakes involving torcular herophili. Such dilatation can result in the formation of a massive venous thrombus leading to ventriculomegaly/hydrocephalus. Although, majority of patients have an unremarkable clinical course owing to spontaneous resolution of the thrombus, significant morbidity and mortality has been documented. We report the first case of torcular thrombosis in a preterm infant who survived severe anemia, consumption coagulopathy and high-output cardiac failure during the neonatal period and had a normal neurological outcome. PMID:22931961

Pandey, V; Dummula, K; Parimi, P

2012-09-01

118

Cardiac output and oxygen uptake relationship during physical effort in men and women over 60 years old  

Microsoft Academic Search

This study investigated the relationship between oxygen uptake (VO2), cardiac output (Q), stroke volume (SV), and heart rate (HR) in 54 men and 77 women (age = 69 ± 5 years) during incremental\\u000a effort. Subjects performed a maximal cycle-ergometer test and VO2 was directly measured. HR and SV were assessed by ECG and cardiograph impedance. Regression equations were calculated for\\u000a Q–VO2, HR–VO2, and Q–HR relationships.

Paulo T. V. Farinatti; Pedro P. S. Soares

2009-01-01

119

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

NASA Technical Reports Server (NTRS)

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

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

2011-01-01

120

The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia  

PubMed Central

Objective: The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared. Results: The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0,001). Conclusion: In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations. PMID:24772126

Duck Shin, Young; Hoon Yim, Kyoung; Hi Park, Sang; Wook Jeon, Yong; Ho Bae, Jin; Soo Lee, Tae; Hwan Kim, Myoung; Jin Choi, Young

2014-01-01

121

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

PubMed Central

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 (V?o2) 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 V?o2 28 (6.3)?ml/kg/min), and 10 healthy controls (32.8 (7.2)?years, peak V?o2 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). V?o2 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 V?o2 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 V?o2 are lower than in patients with CAD with preserved left ventricular function and controls, these patients are able to increase cardiac index adequately during water immersion and swimming. PMID:17164483

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

2007-01-01

122

Optimal dose of landiolol for preventing abrupt changes in both cardiac output and middle cerebral artery flow velocity after electroconvulsive therapy.  

PubMed

The purpose of this study was to examine the dose-dependent effects of landiolol on systemic hemodynamics, cardiac output, and cerebral artery blood flow. Eight patients undergoing electroconvulsive therapy (ECT) received 1 of the 3 drugs/doses (saline, 0.125 mg/kg of landiolol, 0.25 mg/kg of landiolol), in turn, for 3 ECT sessions, immediately after the administration of succinylcholine. In the case of 0.25 mg/kg of landiolol, heart rate, mean arterial pressure, and cardiac output remained unchanged throughout the study period.We believe that 0.25 mg/kg of landiolol may be suitable for preventing the increase in systemic hemodynamics, including cardiac output after ECT. PMID:24755725

Kadoi, Yuji; Saito, Shigeru

2014-09-01

123

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

Microsoft Academic Search

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

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

1998-01-01

124

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

PubMed Central

Increasing evidence shows that goal-directed hemodynamic management can improve outcomes in surgical and intensive care settings. Arterial waveform analysis is one of the different techniques used for guiding goal-directed therapy. Multiple proprietary systems have developed algorithms for obtaining cardiac output from an arterial waveform, including the FloTrac, LiDCO, and PiCCO systems. These systems vary in terms of how they analyze the arterial pressure waveform as well as their requirements for invasive line placement and calibration. Although small-scale clinical trials using these monitors show promising data, large-scale multicenter trials are still needed to better determine how intraoperative goal-directed therapy with arterial waveform analysis can improve patient outcomes. This review provides a comparative analysis of the different arterial waveform monitors for intraoperative goal-directed therapy. PMID:24987744

Fernandez-Bustamante, Ana

2014-01-01

125

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

PubMed Central

Motor neuron activity is transformed into muscle movement through a cascade of complex molecular and biomechanical events. This nonlinear mapping of neural inputs to motor behaviors is called the neuromuscular transform (NMT). We examined the NMT in the cardiac system of the lobster Homarus americanus by stimulating a cardiac motor nerve with rhythmic bursts of action potentials and measuring muscle movements in response to different stimulation patterns. The NMT was similar across preparations, which suggested that it could be used to predict muscle movement from spontaneous neural activity in the intact heart. We assessed this possibility across semi-intact heart preparations in two separate analyses. First, we performed a linear regression analysis across 122 preparations in physiological saline to predict muscle movements from neural activity. Under these conditions, the NMT was predictive of contraction duty cycle but was unable to predict contraction amplitude, likely as a result of uncontrolled interanimal variability. Second, we assessed the ability of the NMT to predict changes in motor output induced by the neuropeptide C-type allatostatin. Wiwatpanit et al. (2012) showed that bath application of C-type allatostatin produced either increases or decreases in the amplitude of the lobster heart contractions. We show that an important component of these preparation-dependent effects can arise from quantifiable differences in the basal state of each preparation and the nonlinear form of the NMT. These results illustrate how properly characterizing the relationships between neural activity and measurable physiological outputs can provide insight into seemingly idiosyncratic effects of neuromodulators across individuals. PMID:24133260

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

2013-01-01

126

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

PubMed Central

Objective Permanent biventricular pacing benefits patients with heart failure and interventricular conduction delay, but the importance of pacing with and without optimization in patients at risk of low cardiac output after heart surgery is unknown. We hypothesized that pacing parameters independently affect cardiac output. Accordingly, we analyzed aortic flow measured with an electromagnetic flowmeter in patients at risk of low cardiac output, during an ongoing randomized clinical trial of biventricular pacing (n=11) vs. standard of care (n=9). Methods A sub-study was conducted in all 20 patients, in both groups, with stable pacing after coronary artery bypass grafting and/or valve surgery. Ejection fraction averaged 33±15%, QRS duration 116±19 msec. Effects were measured within one hour of the conclusion of cardiopulmonary bypass. Atrioventricular delay (7 settings) and interventricular delay (9 settings) were optimized in random sequence. Results Optimization of atrioventricular delay (171±8 msec), at an interventricular delay of 0 msec, increased flow 14% vs. the worst setting (111±11 msec, p < 0.001) and 7% vs. nominal atrioventricular delay (120 msec, p < 0.001). Interventricular delay optimization increased flow 10% vs. the worst setting (p < 0.001) and 5% vs. nominal interventricular delay (0 msec, p < 0.001). Optimized pacing increased cardiac output 13% vs. atrial pacing at matched heart rate (5.5±0.5 vs. 4.9±0.6 L/min; p = 0.003) and 10% vs. sinus rhythm (5.0±0.6 L/min; p = 0.019). Conclusions Temporary biventricular pacing increases intraoperative cardiac output in patients with left ventricular dysfunction undergoing cardiac surgery. Atrioventricular and interventricular delay optimization maximizes this benefit. PMID:20800242

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

2010-01-01

127

[Regulation of cardiac output;an approximation at 3 levels: organic, cellular, and protein].  

PubMed

The heart is the central point for adaptation of the organism to physical exercise because it is the center of the energy support system. Its activity is regulated at three levels; organ, cells and molecular and genetic components. During the development of the heart, the organ adapts in response to chronic and acute overloads by instantaneous functional and chronic changes, leading to a variable degree of cardiac growth. Physical exercise (acute and chronic) is the main example of physiologic overload. The acute response of the heart means a mechanical-hemodynamical and energetic modulation, driving to a final point where oxygen supply fits the increased need. Training, as response to chronic exercise, promotes an increase in energetic capacity (heart rate and stroke volume), structurally reflected in the physiological cardiac hypertrophy. Global functional and structural changes express what is happening at the cellular level. Different stimuli signal through specific receptors and second messengers to the nucleus, regulating gene expression and conditioning structural (size) and functional (contractile) changes. Changes in cellular size explain, by Starling mechanism, the increase in individual contractile strength and in reduction of the ventricular cavity in the systolic period. Other structural changes refer to the interstitium, myocardial vasculature and vascular reactivity. Changes in contractility affect the composition of the contractile elements (isoforms of heavy myosin, light myosin and/or modulatory proteins) and sarcoplasmic Ca2+ regulation, through the increase in Ca2+ flow. Many of the adaptations to chronic exercise studied in vivo in intact heart, isolated heart (Langendorf) or papillary muscle (multicellular preparation), are retained in the cardiomyocyte. Isolated cardiomyocytes can be precisely through the medium, temperature, ionic composition, active substances, etc. Shortening speed without load (Vmax), considered an inotropic index (Sonnenblick) can be measured independently of the initial length. Myocytes shorten against an internal load (restoration force) with viscous and elastic components, although they cannot be loaded externally (stretching is difficult). Cardiomyocyte isolation and maintenance requires strict and controlled conditions. This model offers many possibilities for studying dimensions, contraction-relaxation mechanics, Ca2+ and pH dynamics, beta-adrenergic receptors, electrophysiology, pharmacology, genetics, etc. This kind of studies can deal with normal myocytes or myocytes from trained animals, cardiomyopathies, etc. PMID:10386344

Martíenz Caro, D; Rodríguez García, J A; Munguía, L

1999-01-01

128

An investigation of the changes in aortic diameter and an evaluation of their effect on Doppler measurement of cardiac output in pregnancy  

Microsoft Academic Search

Measurement of cardiac output by means of Doppler ultrasound is based on the velocity of aortic blood flow and therefore requires that aortic diameter should not change between measurements. Work has been published which suggests that, in pregnancy, aortic diameter varies significantly with systemic blood pressure. The implication of this is that aortic diameter must be remeasured for each determination

M. H. Warner; A. C. Fairhead; J. Rawles; F. M. MacLennan

1996-01-01

129

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)

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.

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

1971-01-01

130

Effect of increased alpha-adrenergic activity on the blood pressure/cardiac output relationship in dogs.  

PubMed

The relationship between mean aortic blood pressure (MAP) and cardiac output (CO) was examined in anaesthesized, open-chest dogs during variations in pre-load with and without alpha-adrenergic stimulation with phenylephrine. When phenylephrine increased MAP to 200 mmHg, CO fell greatly and could not be increased by volume expansion. Left ventricular ultrasonic measurements and pressure recordings showed that the Frank-Starling mechanism was maximally activated. During vena cava obstruction CO and MAP fell proportionally. At a lower infusion rate of phenylephrine, MAP increased to 160 mmHg without a great reduction of CO. As in control experiments without phenylephrine infusion, CO could be increased by dextran/saline infusion and lowered about 20% below control by vena cava obstruction with no significant change in MAP; by further caval obstruction CO and MAP fell in proportion. Phenylephrine did not alter the relationship between aortic baroreceptor activity and MAP. The same MAP/CO relationships were obtained before and after bilateral vagotomy and nephrectomy. Caval obstruction and pacing tachycardia resulted in similar MAP/CO relationships despite different effects on left ventricular end-diastolic pressure. Thus, phenylephrine infusion may raise MAP to 200 mmHg but no cardiac reserve is left. During reduction of CO by caval obstruction, peripheral vascular resistance remains constant despite varying baroreceptor activity. At the lower infusion rate of phenylephrine, raising MAP to 160 mmHg, peripheral vascular resistance is constant at low CO, but at high CO the vasoconstrictive effect of phenylephrine is counteracted by a vasodilatory mechanism which seems to be flow-dependent. PMID:2564244

Thorvaldson, J; Ilebekk, A; Aars, H; Kiil, F

1989-02-01

131

Maintaining PGC-1? expression following pressure overload-induced cardiac hypertrophy preserves angiogenesis but not contractile or mitochondrial function.  

PubMed

During pathological hypertrophy, peroxisome proliferator-activated receptor coactivator 1? (PGC-1?) is repressed in concert with reduced mitochondrial oxidative capacity and fatty acid oxidation (FAO). We therefore sought to determine if maintaining or increasing PGC-1? levels in the context of pressure overload hypertrophy (POH) would preserve mitochondrial function and prevent contractile dysfunction. Pathological cardiac hypertrophy was induced using 4 wk of transverse aortic constriction (TAC) in mice overexpressing the human PGC-1? genomic locus via a bacterial artificial chromosome (TG) and nontransgenic controls (Cont). PGC-1? levels were increased by 40% in TG mice and were sustained following TAC. Although TAC-induced repression of FAO genes and oxidative phosphorylation (oxphos) genes was prevented in TG mice, mitochondrial function and ATP synthesis were equivalently impaired in Cont and TG mice after TAC. Contractile function was also equally impaired in Cont and TG mice following TAC, as demonstrated by decreased +dP/dt and ejection fraction and increased left ventricular developed pressure and end diastolic pressure. Conversely, capillary density was preserved, in concert with increased VEGF expression, while apoptosis and fibrosis were reduced in TG relative to Cont mice after TAC. Hence, sustaining physiological levels of PGC-1? expression following POH, while preserving myocardial vascularity, does not prevent mitochondrial and contractile dysfunction. PMID:24776744

Pereira, Renata O; Wende, Adam R; Crum, Ashley; Hunter, Douglas; Olsen, Curtis D; Rawlings, Tenley; Riehle, Christian; Ward, Walter F; Abel, E Dale

2014-08-01

132

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

SciTech Connect

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.

Kinsella, J.P.; Morrow, W.R.; Gerstmann, D.R.; Taylor, A.F.; deLemos, R.A. (Wilford Hall U.S.A.F. Medical Center, San Antonio, TX (USA))

1991-04-01

133

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

PubMed Central

Background Older heart failure (HF) patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF) due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. Methods and Results Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF) (aged 68 ± 10 years) without large (aorta) or medium sized (iliac or femoral artery) vessel atherosclerosis, and 13 age and gender matched healthy volunteers underwent a sophisticated battery of assessments including a) peak exercise oxygen consumption (peak VO2), b) physical function, c) cardiovascular magnetic resonance (CMR) submaximal exercise measures of aortic and femoral arterial blood flow, and d) determination of thigh muscle area. Peak VO2 was reduced in HF subjects (14 ± 3 ml/kg/min) compared to healthy elderly subjects (20 ± 6 ml/kg/min) (p = 0.01). Four-meter walk speed was 1.35 ± 0.24 m/sec in healthy elderly verses 0.98 ± 0.15 m/sec in HF subjects (p < 0.001). After submaximal exercise, the change in superficial femoral LBF was reduced in HF participants (79 ± 92 ml/min) compared to healthy elderly (222 ± 108 ml/min; p = 0.002). This occurred even though submaximal stress-induced measures of the flow in the descending aorta (5.0 ± 1.2 vs. 5.1 ± 1.3 L/min; p = 0.87), and the stress-resting baseline difference in aortic flow (1.6 ± 0.8 vs. 1.7 ± 0.8 L/min; p = 0.75) were similar between the 2 groups. Importantly, the difference in submaximal exercise induced superficial femoral LBF between the 2 groups persisted after accounting for age, gender, body surface area, LVEF, and thigh muscle area (p ? 0.03). Conclusion During CMR submaximal bike exercise in the elderly with heart failure, mechanisms other than low cardiac output are responsible for reduced lower extremity blood flow. PMID:19922666

2009-01-01

134

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...

135

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

PubMed

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

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

2014-10-01

136

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

PubMed

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. PMID:19137850

Akbarzadeh, F; Toufan, Mehrnoush

2008-10-15

137

The 24 h pattern of arterial pressure in mice is determined mainly by heart rate?driven variation in cardiac output  

PubMed Central

Abstract Few studies have systematically investigated whether daily patterns of arterial blood pressure over 24 h are mediated by changes in cardiac output, peripheral resistance, or both. Understanding the hemodynamic mechanisms that determine the 24 h patterns of blood pressure may lead to a better understanding of how such patterns become disturbed in hypertension and influence risk for cardiovascular events. In conscious, unrestrained C57BL/6J mice, we investigated whether the 24 h pattern of arterial blood pressure is determined by variation in cardiac output, systemic vascular resistance, or both and also whether variations in cardiac output are mediated by variations in heart rate and or stroke volume. As expected, arterial pressure and locomotor activity were significantly (P < 0.05) higher during the nighttime period compared with the daytime period when mice are typically sleeping (+12.5 ± 1.0 mmHg, [13%] and +7.7 ± 1.3 activity counts, [254%], respectively). The higher arterial pressure during the nighttime period was mediated by higher cardiac output (+2.6 ± 0.3 mL/min, [26%], P < 0.05) in association with lower peripheral resistance (?1.5 ± 0.3 mmHg/mL/min, [?13%] P < 0.05). The increased cardiac output during the nighttime was mainly mediated by increased heart rate (+80.0 ± 16.5 beats/min, [18%] P < 0.05), as stroke volume increased minimally at night (+1.6 ± 0.5 ?L per beat, [6%] P < 0.05). These results indicate that in C57BL/6J mice, the 24 h pattern of blood pressure is hemodynamically mediated primarily by the 24 h pattern of cardiac output which is almost entirely determined by the 24 h pattern of heart rate. These findings suggest that the differences in blood pressure between nighttime and daytime are mainly driven by differences in heart rate which are strongly correlated with differences in locomotor activity. PMID:25428952

Kurtz, Theodore W.; Lujan, Heidi L.; DiCarlo, Stephen E.

2014-01-01

138

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

PubMed Central

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

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

2011-01-01

139

A new impedance cardiograph device for the non-invasive evaluation of cardiac output at rest and during exercise: comparison with the “direct” Fick method  

Microsoft Academic Search

The objectives of this study were to evaluate the reliability and accuracy of a new impedance cardiograph device, the Physio\\u000a Flow, at rest and during a steady-state dynamic leg exercise (work intensity ranging from 10 to 50?W) performed in the supine\\u000a position. We compared cardiac output determined simultaneously by two methods, the Physio Flow (Q?\\u000a cPF) and the direct Fick

Anne Charloux; Evelyne Lonsdorfer-Wolf; Ruddy Richard; Eliane Lampert; Monique Oswald-Mammosser; Bertrand Mettauer; Bernard Geny; Jean Lonsdorfer

2000-01-01

140

Comparison Between Cardiac Output Measured by the Pulmonary Arterial Thermodilution Technique and that Measured by the Femoral Arterial Thermodilution Technique in a Pediatric Animal Model  

Microsoft Academic Search

This study compares the correlation between two methods for the determination of cardiac output—the pulmonary arterial thermodilution technique using the Swan–Ganz catheter and the femoral arterial thermodilution technique using a pulse contour analysis computer (PiCCO) catheter. We performed a prospective animal study using 16 immature Maryland pigs weighing 9 to 16 kg. A 5.5- or 7.5-Fr Swan–Ganz catheter was introduced

M. Rupérez; J. López-Herce; C. García; C. Sánchez; E. García; D. Vigil

2004-01-01

141

The effects of cardiac output and pulmonary arterial hypertension on volumetric capnography derived-variables during normoxia and hypoxia.  

PubMed

The aim of this study was to test the effect of cardiac output (CO) and pulmonary artery hypertension (PHT) on volumetric capnography (VCap) derived-variables. Nine pigs were mechanically ventilated using fixed ventilatory settings. Two steps of PHT were induced by IV infusion of a thromboxane analogue: PHT25 [mean pulmonary arterial pressure (MPAP) of 25 mmHg] and PHT40 (MPAP of 40 mmHg). CO was increased by 50 % from baseline (COup) with an infusion of dobutamine ?5 ?g kg(-1) min(-1) and decreased by 40 % from baseline (COdown) infusing sodium nitroglycerine ?30 ?g kg(-1) min(-1) plus esmolol 500 ?g kg(-1) min(-1). Another state of PHT and COdown was induced by severe hypoxemia (FiO2 0.07). Invasive hemodynamic data and VCap were recorded and compared before and after each step using a mixed random effects model. Compared to baseline, the normalized slope of phase III (SnIII) increased by 32 % in PHT25 and by 22 % in PHT40. SnIII decreased non-significantly by 4 % with COdown. A combination of PHT and COdown associated with severe hypoxemia increased SnIII by 28 % compared to baseline. The elimination of CO2 per breath decreased by 7 % in PHT40 and by 12 % in COdown but increased only slightly with COup. Dead space variables did not change significantly along the protocol. At constant ventilation and body metabolism, pulmonary artery hypertension and decreases in CO had the biggest effects on the SnIII of the volumetric capnogram and on the elimination of CO2. PMID:24908108

Mosing, Martina; Kutter, Annette P N; Iff, Samuel; Raszplewicz, Joanna; Mauch, Jacqueline; Bohm, Stephan H; Tusman, Gerardo

2015-02-01

142

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

PubMed Central

Introduction The response to exogenous epinephrine (Ep) is difficult to predict given the multitude of factors involved such as broad pharmacokinetic and pharmacodynamic between-subject variabilities, which may be more pronounced in children. We investigated the pharmacokinetics and pharmacodynamics of Ep, co-administered with milrinone, in children who underwent open heart surgical repair for congenital defects following cardiopulmonary bypass, including associated variability factors. Methods Thirty-nine children with a high risk of low cardiac output syndrome were prospectively enrolled. Ep pharmacokinetics, hemodynamic and metabolic effects were analyzed using the non-linear mixed effects modeling software MONOLIX. According to the final model, an Ep dosing simulation was suggested. Results Ep dosing infusions ranged from 0.01 to 0.23 ?g.kg-1.min-1 in children whose weight ranged from 2.5 to 58 kg. A one-compartment open model with linear elimination adequately described the Ep concentration-time courses. Bodyweight (BW) was the main covariate influencing clearance (CL) and endogenous Ep production rate (q0) via an allometric relationship: CL(BWi)?=??CL x (BWi)3/4 and q0(BWi)?=??q0 x (BWi )3/4. The increase in heart rate (HR) and mean arterial pressure (MAP) as a function of Ep concentration were well described using an Emax model. The effect of age was significant on HR and MAP basal level parameters. Assuming that Ep stimulated the production rate of plasma glucose, the increases in plasma glucose and lactate levels were well described by turnover models without any significant effect of age, BW or exogenous glucose supply. Conclusions According to this population analysis, the developmental effects of BW and age explained a part of the pharmacokinetic and pharmacodynamics between-subject variabilities of Ep administration in critically ill children. This approach ultimately leads to a valuable Ep dosing simulation which should help clinicians to determine an appropriate a priori dosing regimen. PMID:24456639

2014-01-01

143

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

SciTech Connect

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.

Yan, Lifeng [State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029 (China); Zhou, Yong [Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China); Yu, Shanhe [Shanghai Institute of Hematology, RuiJin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025 (China); Ji, Guixiang [Nanjing Institute of Environmental Sciences/Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection, Nanjing 210042 (China); Wang, Lei [Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China); Liu, Wei [State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029 (China); Gu, Aihua, E-mail: aihuagu@njmu.edu.cn [State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029 (China)

2013-11-15

144

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

PubMed

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

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

2013-12-01

145

Reduced heart rate and cardiac output differentially affect angiogenesis, growth, and development in early chicken embryos (Gallus domesticus).  

PubMed

An increase in both vascular circumferential tension and shear stress in the developing vasculature of the chicken embryo has been hypothesized to stimulate angiogenesis in the developing peripheral circulation chorioallantoic membrane (CAM). To test this hypothesis, angiogenesis in the CAM, development, and growth were measured in the early chicken embryo, following acute and chronic topical application of the purely bradycardic drug ZD7288. At hour 56, ZD7288 reduced heart rate (f(H)) by ~30% but had no significant effect on stroke volume (~0.19 ± 0.2 ?L), collectively resulting in a significant fall in cardiac output (CO) from ~27 ± 3 to 18 ± 2 ?L min(-1). Mean f(H) at 72 h of development was similarly significantly lowered by acute ZD7288 treatment (250 ?M) to 128 ± 0.3 beats min(-1), compared with 174.5 ± 0.3 and 174.7 ± 0.8 beats min(-1) in control and Pannett-Compton (P-C) saline-treated embryos, respectively. Chronic dosing with ZD7288-and the attendant decreases in f(H) and CO-did not change eye diameter or cervical flexion (key indicators of development rate) at 120 h but significantly reduced overall growth (wet and dry body mass decreased by 20%). CAM vessel density index (reflecting angiogenesis) measured 200-400 ?m from the umbilical stalk was not altered, but ZD7288 reduced vessel numbers-and therefore vessel density-by 13%-16% more distally (500-600 ?m from umbilical stalk) in the CAM. In the ZD7288-treated embryos, a decrease in vessel length was found within the second branch order (~300-400 ?m from the umbilical stock), while a decrease in vessel diameter was found closer to the umbilical stock, beginning in the first branch order (~200-300 ?m). Paradoxically, chronic application of P-C saline also reduced peripheral CAM vessel density index at 500 and 600 ?m by 13% and 7%, respectively, likely from washout of local angiogenic factors. In summary, decreased f(H) with reduced CO did not slow development rate but reduced embryonic growth rate and angiogenesis in the CAM periphery. This study demonstrates for the first time that different processes in the ontogeny of the early vertebrate embryo (i.e., hypertrophic growth vs. development) have differential sensitivities to altered convective blood flow. PMID:23629887

Branum, Sylvia R; Yamada-Fisher, Miho; Burggren, Warren

2013-01-01

146

Cardiac Function and Architecture Are Maintained in a Model of Cardiorestricted Overexpression of the Prorenin-Renin Receptor  

PubMed Central

The (pro)renin-renin receptor, (P)RR has been claimed to be a novel element of the renin-angiotensin system (RAS). The function of (P)RR has been widely studied in renal and vascular pathology but the cardio-specific function of (P)RR has not been studied in detail. We therefore generated a transgenic mouse (Tg) with cardio-restricted (P)RR overexpression driven by the alpha-MHC promotor. The mRNA expression of (P)RR was ?170-fold higher (P<0.001) and protein expression ?5-fold higher (P<0.001) in hearts of Tg mice as compared to non-transgenic (wild type, Wt) littermates. This level of overexpression was not associated with spontaneous cardiac morphological or functional abnormalities in Tg mice. To assess whether (P)RR could play a role in cardiac hypertrophy, we infused ISO for 28 days, but this caused an equal degree of cardiac hypertrophy and fibrosis in Wt and Tg mice. In addition, ischemia-reperfusion injury was performed in Langendorff perfused isolated mouse hearts. We did not observe differences in parameters of cardiac function or damage between Wt and Tg mouse hearts under these conditions. Finally, we explored whether the hypoxia sensing response would be modulated by (P)RR using HeLa cells with and without (P)RR overexpression. We did not establish any effect of (P)RR on expression of genes associated with the hypoxic response. These results demonstrate that cardio-specific overexpression of (P)RR does not provoke phenotypical differences in the heart, and does not affect the hearts’ response to stress and injury. It is concluded that increased myocardial (P)RR expression is unlikely to have a major role in pathological cardiac remodeling. PMID:24587131

Mahmud, Hasan; Candido, Wellington Mardoqueu; van Genne, Linda; Vreeswijk-Baudoin, Inge; Yu, Hongjuan; van de Sluis, Bart; van Deursen, Jan; van Gilst, Wiek H.; Silljé, Herman H. W.; de Boer, Rudolf A.

2014-01-01

147

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

PubMed

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

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

2010-03-01

148

Effects of TIPS on global end-diastolic volume and cardiac output and renal resistive index in ICU patients with advanced alcoholic cirrhosis.  

PubMed

The transjugular porto-systemic stent-shunt (TIPS) reduces portal pressure in cirrhotic patients and is used as a nonsurgical treatment for refractory ascites, recurrent variceal hemorrhage or hepatorenal syndrome. There are concerns regarding a negative impact on cirrhotic cardiomyopathy and deterioration of hyperkinetic circulatory dysfunction. We analyzed a prospectively maintained database containing hemodynamic data on cirrhotic ICU patients. Hemodynamic monitoring was performed using transpulmonary thermodilution (PiCCO, Pulsion Medical Systems, Munich, Germany). Renal perfusion was assessed by Doppler ultrasound during studies of portal and TIPS perfusion before and after the procedure. Complete data sets of 8 patients (4 male, 4 female, age 60 years (52-67), Child-Pugh-Turcotte score 10 (8-12)) were available. After TIPS, there was a substantial increase of GEDVI (646 ml/m2 (580-737) to 663 mL/m2 (643-792); p=0.036) that was even more pronounced at 24 hours (716 mL/m2 (663-821); P=0.012). CI increased from 3.3 L/min/m2 (3.1-4.2) to 3.9 L/min/m2 (3.6-5.3) (p=0.012) and 3.9 L/min/m2 (3.7-5.2) (p=0.017), respectively. There was a significant decrease of renal RI from 0.810 (0.781-0.864) to 0.746 (0.710-0.798) (p=0.028) and a transient increase of fractional excretion of sodium. SVRI (1737 dyn*s/cm5/m2 (1088 . 2115) vs. 1917 dyn*s/cm5/m2 (1368-2177) was not significantly altered immediately after TIPS but decreased to 1495 dyn*s/cm5/m2 (833- 1765) at 24 hours (p=0.036). There were no significant changes of mean arterial pressure (MAP). In conclusion, TIPS resulted in a pronounced increase of central blood volume. The observed hemodynamic effects are compatible with a preload driven increase of cardiac output and secondary decreases in SVRI and RI. PMID:20308721

Umgelter, Andreas; Reindl, Wolfgang; Geisler, Fabian; Saugel, Bernd; Huber, Wolfgang; Berger, Hermann; Schmid, Roland M

2010-01-01

149

Trending ability and limitations of transpulmonary thermodilution and pulse contour cardiac output measurement in cats as a model for pediatric patients.  

PubMed

The present study evaluated transpulmonary thermodilution (TPTD) and pulse contour cardiac output (PCCO) both measured by the PiCCO Plus™ monitor (Pulsion Medical Systems, Munich, Germany) against pulmonary artery thermodilution (PATD) in cats as a hemodynamic model for small children. A wide range of cardiac outputs (CO) was simultaneously measured. Accuracy and trending abilities were critically evaluated. Three cats were studied under isoflurane anesthesia and 160 CO measurements were performed with 3 mL ice-cold 5 % dextrose with PATD and TPTD. The results were compared with the PCCO measurement before the bolus measurement. Cardiac output was manipulated from 32 to 224 mL/kg/min by dobutamine, dopamine, phenylephrine, medetomidine and increased concentrations of isoflurane. Bland-Altman analysis, concordance and polar plot analysis were performed to assess accuracy and trending ability. TPTD was measuring constantly higher than PATD with a mean bias of 73 mL/kg/min and limits of agreement of 34-112 mL/kg/min, a concordance rate of 94 % and a mean polar angle of -5° with radial limits of agreement (RLOA) of 33°. Concordance rate of the PCCO versus PATD was 82 % with a mean polar angle of -10° and RLOA of 46° and versus TPTD 90 % with a mean polar angle of -6° and RLOA of 46°. Both tested methods constantly overestimated simultaneous PATD measurements. The small size, low flows and the relative short catheter not reaching the abdominal aorta may explain that. However TPTD tracked changes accurately opposed to a poor trending ability of the PCCO measurement. PMID:25228023

Kutter, Annette P N; Bektas, Rima N; Hofer, Christoph K; Larenza Menzies, M Paula; Bettschart-Wolfensberger, Regula

2014-09-17

150

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

SciTech Connect

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.

Tateishi, Kento [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan)]|[Department of Cardiovascular Medicine, Kyoto Prefectural University School of Medicine, Kyoto 602-8566 (Japan); Ashihara, Eishi [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan); Honsho, Shoken [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan)]|[Department of Cardiovascular Medicine, Kyoto Prefectural University School of Medicine, Kyoto 602-8566 (Japan); Takehara, Naofumi [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan); Nomura, Tetsuyaital [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan)]|[Department of Cardiovascular Medicine, Kyoto Prefectural University School of Medicine, Kyoto 602-8566 (Japan); Takahashi, Tomosaburo [Department of Cardiovascular Medicine, Kyoto Prefectural University School of Medicine, Kyoto 602-8566 (Japan); Ueyama, Tomomi [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan); Yamagishi, Masaaki; Yaku, Hitoshi [Department of Cardiovascular Surgery, Kyoto Prefectural University School of Medicine, Kyoto 602-8566 (Japan); Matsubara, Hiroaki [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan)]|[Department of Cardiovascular Medicine, Kyoto Prefectural University School of Medicine, Kyoto 602-8566 (Japan)]. E-mail: matsubah@koto.kpu-m.ac.jp; Oh, Hidemasa [Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, Kyoto 606-8507 (Japan)]. E-mail: hidemasa@kuhp.kyoto-u.ac.jp

2007-01-19

151

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

PubMed

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

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

2014-06-01

152

Co-administration of ephedrine prevents reductions in cardiac output and systemic oxygen delivery secondary to lung compression maneuvers during one-lung ventilation, without reducing arterial oxygenation  

Microsoft Academic Search

Purpose  We previously showed that compression of the nondependent lung during one-lung ventilation (OLV) in patients undergoing esophagectomy\\u000a improves arterial oxygenation but impairs cardiac output (CO) and systemic oxygen delivery (DO2). The objective of this study was to test the hypothesis that the combination of nondependent lung compression and ephedrine\\u000a improves arterial oxygenation without compromising DO2.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Twenty patients undergoing esophagectomy through

Seiji Ishikawa; Fumi Makino; Satomi Kobinata; Hiroyuki Ito; Tatsuyuki Kawano; Koshi Makita

2011-01-01

153

[The effect of an intracardiac left-right shunt on thermodilution measurements of cardiac output. An extracorporeal circulation model].  

PubMed

Thermodilution measurements of cardiac output (CO) by means of Swan-Ganz catheters, in a strict sense, represent pulmonary arterial blood flow (PBF). In principle, this is also true in the presence of intracardiac left-to-right shunts due to atrial or ventricular septal defects. However, early recirculation of indicator may give rise to serious methodological problems in these cases. We sought to determine the influence of intracardiac left-to-right shunts on different devices for thermodilution measurements of CO using an extra-corporeal flow model. METHODS. Blood flow was regulated by means of a centrifugal pump that at the same time enabled complete mixing of the indicator after injection (Fig. 1). Pulmonary and systemic parts of the circulation were simulated using two membrane oxygenators and a systemic-venous reservoir to delay systemic recirculation of indicator. Control measurements of PBF (Qp) and systemic (Qs) blood flow were performed by calibrated electromagnetic flow-meters (EMF). Blood temperature was kept constant using a heat exchanger without altering the indicator mass balance in the pulmonary circulation. Left-to-right shunt was varied at different systemic flow levels applying a Qp:Qs ratio ranging from 1:1 to 2.5:1. Thermodilution measurements of PBF were performed using two different thermodilution catheters that were connected to commercially available CO computers. Additionally, thermodilution curves were recorded on a microcomputer and analysed with custom-made software that enabled iterative regression analyses of the initial decay to determine that part of the downslope that best fits a mono-exponentially declining function. Extrapolation of the thermodilution curve was then based on the respective curve segment in order to eliminate indicator recirculation due to shunt flow. RESULTS. At moderate left-to-right shunts (Qp:Qs < 2:1) all thermodilution measurements showed close agreement with control measurements. At higher shunt flows (Qp:Qs > or = 2:1), however, conventional extrapolation procedures of CO computers considerably underestimated PBF (Fig. 2). This was particularly true when a slow-response thermistor catheter was used (Fig. 3). The reason for this underestimation of Qp was an overestimation of the area under curve because of inadequate mathematical elimination of indicator recirculation by standard truncation methods (Fig. 4). However, curve-alert messages of the commercially implemented software did not occur. A high level of agreement could be consistently obtained using a fast-response thermistor together with individual definition of extrapolation limits according to logarithmic regression analyses. DISCUSSION AND CONCLUSION. Under varying levels of left-to-right shunt, both the response time of thermodilution catheters and the algorithms for calculation of flow considerably influenced the validity of thermodilution measurements of PBF in an extracorporeal flow model. The use of computer-based regression analyses to define the optimal segment for monoexponential extrapolation could effectively eliminate indicator recirculation from the initial portion of the declining thermodilution curve and showed the closest agreement with EMF measurements of Qp. The quality of thermodilution curves with respect to recirculation peaks in the flow model was slightly better than in clinical routine. Nevertheless, the clinical applicability of the modified extrapolation algorithm could be illustrated during pulmonary thermodilution measurements in an exemplary patient with a ventricular septal defect (Fig. 5). PBF at extremely high shunt ratios, however, cannot be assessed by monoexponential extrapolation in principle (Fig. 6). Insufficient elimination of indicator recirculation resulted in flow values that closely resembled systemic rather than PBF. This finding is in accordance with a mathematical analysis of the underlying Steward-Hamilton equation if an infinite number of recirculations would be PMID:7695076

Weyland, A; Wietasch, G; Hoeft, A; Buhre, W; Allgeier, B; Weyland, W; Kettler, D

1995-01-01

154

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

PubMed Central

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

2014-01-01

155

Blood flow in the common carotid artery in term and preterm infants: reproducibility and relation to cardiac output  

Microsoft Academic Search

Aim: To assess the reproducibility of, and determine normative data for, flow volume measurements from the right common carotid artery (CCA) and its relation to left ventricular output (LVO) in stable term and preterm babies using Doppler ultrasound.Methods: Right CCA flow volume was measured using a near focus, high frequency transducer by obtaining intensity weighted mean velocity and right CCA

A K Sinha; C Cane; S T Kempley

2006-01-01

156

Clinical Significance of a Spiral Phenomenon in the Plot of CO2 Output Versus O2 Uptake During Exercise in Cardiac Patients.  

PubMed

A spiral phenomenon is sometimes noted in the plots of CO2 output (VCO2) against O2 uptake (VO2) measured during cardiopulmonary exercise testing (CPX) in patients with heart failure with oscillatory breathing. However, few data are available that elucidate the clinical significance of this phenomenon. Our group studied the prevalence of this phenomenon and its relation to cardiac and cardiopulmonary function. Of 2,263 cardiac patients who underwent CPX, 126 patients with a clear pattern of oscillatory breathing were identified. Cardiopulmonary indexes were compared between patients who showed the spiral phenomenon (n = 49) and those who did not (n = 77). The amplitudes of VO2 and VCO2 oscillations were greater and the phase difference between VO2 and VCO2 oscillations was longer in the patients with the spiral phenomenon than in those without it. Patients with the spiral phenomenon also had a lower left ventricular ejection fraction (43.4 ± 21.4% vs 57.1 ± 16.8%, p <0.001) and a higher level of brain natriuretic peptide (637.2 ± 698.3 vs 228.3 ± 351.4 pg/ml, p = 0.002). The peak VO2 was lower (14.5 ± 5.6 vs 18.1 ± 6.3, p = 0.002), the slope of the increase in ventilation versus VCO2 was higher (39.8 ± 9.5 vs 33.6 ± 6.8, p <0.001), and end-tidal PCO2 both at rest and at peak exercise was lower in the patients with the spiral phenomenon than in those without it. In conclusion, the spiral phenomenon in the VCO2-versus-VO2 plot arising from the phase difference between VCO2 and VO2 oscillations reflects more advanced cardiopulmonary dysfunction in cardiac patients with oscillatory breathing. PMID:25591892

Nagayama, Osamu; Koike, Akira; Himi, Tomoko; Sakurada, Koji; Kato, Yuko; Suzuki, Shinya; Sato, Akira; Yamashita, Takeshi; Wasserman, Karlman; Aonuma, Kazutaka

2015-03-01

157

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

PubMed

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

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

2009-02-01

158

Sex differences in carotid baroreflex control of arterial blood pressure in humans: relative contribution of cardiac output and total vascular conductance  

PubMed Central

It is presently unknown whether there are sex differences in the magnitude of blood pressure (BP) responses to baroreceptor perturbation or if the relative contribution of cardiac output (CO) and total vascular conductance (TVC) to baroreflex-mediated changes in BP differs in young women and men. Since sympathetic vasoconstrictor tone is attenuated in women, we hypothesized that carotid baroreflex-mediated BP responses would be attenuated in women by virtue of a blunted vascular response (i.e., an attenuated TVC response). BP, heart rate (HR), and stroke volume were continuously recorded during the application of 5-s pulses of neck pressure (NP; carotid hypotension) and neck suction (NS; carotid hypertension) ranging from +40 to ?80 Torr in women (n = 20, 21 ± 0.5 yr) and men (n = 20, 21 ± 0.4 yr). CO and TVC were calculated on a beat-to-beat basis. Women demonstrated greater depressor responses to NS (e.g., ?60 Torr, ?17 ± 1%baseline in women vs. ?11 ± 1%baseline in men, P < 0.05), which were driven by augmented decreases in HR that, in turn, contributed to larger reductions in CO (?60 Torr, ?15 ± 2%baseline in women vs. ?6 ± 2%baseline in men, P < 0.05). In contrast, pressor responses to NP were similar in women and men (e.g., +40 Torr, +14 ± 2%baseline in women vs. +10 ± 1%baseline in men, P > 0.05), with TVC being the primary mediating factor in both groups. Our findings indicate that sex differences in the baroreflex control of BP are evident during carotid hypertension but not carotid hypotension. Furthermore, in contrast to our hypothesis, young women exhibited greater BP responses to carotid hypertension by virtue of a greater cardiac responsiveness. PMID:21963834

Kim, Areum; Deo, Shekhar H.; Vianna, Lauro C.; Balanos, George M.; Hartwich, Doreen; Fisher, James P.

2011-01-01

159

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

PubMed Central

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

2013-01-01

160

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

PubMed Central

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

Bishop, C. M.

1997-01-01

161

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

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. PMID:24322474

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

162

I-Band Titin in Cardiac Muscle Is a Three-Element Molecular Spring and Is Critical for Maintaining Thin Filament Structure  

Microsoft Academic Search

In cardiac muscle, the giant protein titin ex- ists in different length isoforms expressed in the mole- cule's I-band region. Both isoforms, termed N2-A and N2-B, comprise stretches of Ig-like modules separated by the PEVK domain. Central I-band titin also contains isoform-specific Ig-motifs and nonmodular sequences, notably a longer insertion in N2-B. We investigated the elastic behavior of the I-band

Wolfgang A. Linke; Diane E. Rudy; Thomas Centner; Mathias Gautel; Christian Witt; Siegfried Labeit; Carol C. Gregorio

1999-01-01

163

Cardiac gated ventilation  

SciTech Connect

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

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

1995-12-31

164

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 ...

165

Cardiac Fibroblast: The Renaissance Cell  

PubMed Central

The permanent cellular constituents of the heart include cardiac fibroblasts, myocytes, endothelial cells and vascular smooth muscle cells. Previous studies have demonstrated that there are undulating changes in cardiac cell populations during embryonic development, through neonatal development and into the adult. Transient cell populations include lymphocytes, mast cells and macrophages, which can interact with these permanent cell types to affect cardiac function. It has also been observed that there are marked differences in the makeup of the cardiac cell populations depending on the species, which may be important when examining myocardial remodeling. Current dogma states that the fibroblast makes up the largest cell population of the heart; however, this appears to vary for different species, especially mice. Cardiac fibroblasts play a critical role in maintaining normal cardiac function, as well as in cardiac remodeling during pathological conditions such as myocardial infarct and hypertension. These cells have numerous functions, including synthesis and deposition of extracellular matrix, cell-cell communication with myocytes, cell-cell signaling with other fibroblasts, as well as with endothelial cells. These contacts affect the electrophysiological properties, secretion of growth factors and cytokines, as well as potentiating blood vessel formation. While a plethora of information is known about several of these processes, relatively little is understood about fibroblasts and their role in angiogenesis during development or cardiac remodeling. In this review we provide insight into the various properties of cardiac fibroblasts that helps illustrate their importance in maintaining proper cardiac function, as well as their critical role in the remodeling heart. PMID:19959782

Souders, Colby A.; Bowers, Stephanie L.K.; Baudino, Troy A.

2012-01-01

166

Cardiac Amyloidosis  

MedlinePLUS

... pdf/view ). Previous Section Next Section Sources of Funding Dr Quarta received funding from the “Istituto Nazionale per le Ricerche Cardiovascolari ( ... Women's Hospital Cardiac Amyloidosis Fund. Dr Falk received funding from the Brigham and Women's Hospital Cardiac Amyloidosis ...

167

Overload protection circuit for output driver  

DOEpatents

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.

Stewart, Roger G. (Neshanic Station, NJ)

1982-05-11

168

The cardiac lymphatic system.  

PubMed

The lymphatic system, a network of vessels carrying clear interstitial fluid called lymph, is found throughout the human body. The system maintains homeostasis, receiving proteins and excess fluid from the interstitial tissues, and returning them to the venous system. Understanding of lymphatic drainage remains important in the diagnosis, prognosis, and treatment of diseases, including the metastasis of malignant diseases. Information specific to the cardiac lymphatics is scarce. Indeed, quite often the topic is not even mentioned in many medical textbooks. The goal of our review is to compile and analyze the information currently available concerning the cardiac lymphatics, hoping further to demonstrate the clinical importance of this neglected system. PMID:21387415

Loukas, Marios; Abel, Nicole; Tubbs, R Shane; Grabska, Joanna; Birungi, Judith; Anderson, Robert H

2011-09-01

169

IMPROVING CARDIAC FUNCTION WITH NEW GENERATION PLASMA VOLUME EXPANDERS  

PubMed Central

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

Chatpun, Surapong; Nacharaju, Parimala; Cabrales, Pedro

2012-01-01

170

Advanced Imaging Applications to Cardiac Resynchronization Therapy  

E-print Network

Advanced Imaging Applications to Cardiac Resynchronization Therapy Justin D. Pearlman Professor pacemaker leads can be placed to improve cardiac output, avoiding areas of dead tissue, and achieving of Medicine and Radiology Director of Advanced CV Imaging Dartmouth 4pm, Wed, Jan. 31, 2007 Auditorium

Zanibbi, Richard

171

[Cardiac sarcoidosis].  

PubMed

Cardiac sarcoidosis induces heart failure death or sudden death in many cases and is thus often associated with a poor prognosis. In Japan 47-78% of sarcoidosis patients die of cardiac lesions. Early diagnosis is important in such cases, and a comprehensive judgment based on the endomyocardial biopsy, echocardiography and nuclear medicine examination findings should be made according to the 'Handbook of the Diagnosis of Cardiac Sarcoidosis'. Once a diagnosis is made the introduction of steroid therapy should be considered. Steroid administration should be conducted referring to the 'Guidelines to the Treatment of Cardiac Sarcoidosis'. PMID:12233077

Uemura, Akihisa; Morimoto, Shin-ichiro

2002-09-01

172

Redox Control of Cardiac Excitability  

PubMed Central

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

Aggarwal, Nitin T.

2013-01-01

173

Maintaining Maintainability = Recognizing Reachability Tim Menzies  

E-print Network

Maintaining Maintainability = Recognizing Reachability Tim Menzies NASA/WVU IV&V Facility 100 University Drive, Fairmont WV 26554, USA tim@menzies.com;http://www.tim.menzies.com Bojan Cukic Dept an operational profile). White-box (WB) testing costs more than black-box to define: analysts must reflect over

Menzies, Tim

174

Renal perfusion index reflects cardiac systolic function in chronic cardio-renal syndrome.  

PubMed

Background Cardiac dysfunction can modify renal perfusion, which is crucial to maintain sufficient kidney tissue oxygenation. Renal cortex perfusion assessed by dynamic ultrasound method is related both to renal function and cardiac hemodynamics. The aim of the study was to test the hypothesis that Renal Perfusion Index (RPI) can more closely reflect cardiac hemodynamics and differentiate etiology of chronic cardio-renal syndrome. Material and Methods Twenty-four patients with hypertension and chronic kidney disease (CKD) at 2-4 stage (12 with hypertensive nephropathy and 12 with CKD prior to hypertension) were enrolled in the study. Blood tests, 24-h ABPM, echocardiography, and ultrasonography with estimation of Total renal Cortical Perfusion intensity and Renal Perfusion Index (RPI) were performed. Results In the group of all patients, RPI correlated with left ventricular stoke volume (LVSV), and cardiac index, but not with markers of renal function. In multiple stepwise regression analysis CKD-EPI(Cys-Cr) (b=-0.360), LVSV (b=0.924) and MAP (b=0.376) together independently influenced RPI (R2=0.74; p<0.0001). RPI<0.567 allowed for the identification of patients with chronic cardio-renal syndrome with sensitivity of 41.7% and specificity of 83.3%. Conclusions Renal perfusion index relates more strongly to cardiac output than to renal function, and could be helpful in recognizing chronic cardio-renal syndrome. Applicability of RPI in diagnosing early abnormalities in the cardio-renal axis requires further investigation. PMID:25881555

Lubas, Arkadiusz; Ryczek, Robert; Kade, Grzegorz; Niemczyk, Stanis?aw

2015-01-01

175

Cardiac Catheterization  

MedlinePLUS

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

176

CARDIAC MUSCLE  

PubMed Central

Cardiac muscle fibers of the hummingbird and finch have no transverse tubules and are smaller in diameter than those of mammalian hearts. The fibers are connected by intercalated discs which are composed of desmosomes and f. adherentes; small nexuses are often interspersed. As in cardiac muscle of several other animals, the junctional SR of the couplings is highly structured in these two birds but, in addition, and after having lost sarcolemmal contact, the junctional SR continues beyond the coupling to extend deep into the interior of the cells and to form belts around the Z-I regions of the sarcomeres. This portion of the sarcoplasmic reticulum, which we have named "extended junctional SR," and which is so prominent and invariant a feature of cardiac cells of hummingbirds and finches, has not been observed in chicken cardiac cells. The morphological differences between these species of birds may be related to respective differences in heart rates characteristic for these birds. PMID:5555579

Jewett, Paul H.; Sommer, J. R.; Johnson, E. A.

1971-01-01

177

Cardiac Aspergillosis  

Microsoft Academic Search

\\u000a Cardiac aspergillosis has been increasingly recognized as a complication of immunocompromise in recent times. The use of progressively\\u000a more potent immunosuppressive agents and the longer survival times of transplant recipients is likely contributing to an increasing\\u000a prevalence of the disease. Although still uncommon, the disease has an extremely high mortality rate and management remains\\u000a difficult. Cardiac aspergillosis can present as

Philippe Lagacé-Wiens; Ethan Rubinstein

178

Nuclear cardiac  

SciTech Connect

The relationship between nuclear medicine and cardiology has continued to produce a surfeit of interesting, illuminating, and important reports involving the analysis of cardiac function, perfusion, and metabolism. To simplify the presentation, this review is broken down into three major subheadings: analysis of myocardial perfusion; imaging of the recent myocardial infarction; and the evaluation of myocardial function. There appears to be an increasingly important relationship between cardiology, particularly cardiac physiology, and nuclear imaging techniques. (KRM)

Slutsky, R.; Ashburn, W.L.

1982-01-01

179

Cardiac factors in orthostatic hypotension  

NASA Astrophysics Data System (ADS)

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

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

180

Cardiac cephalgia.  

PubMed

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

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

2015-04-01

181

Polarization-maintaining property of tapered polarization-maintaining fibers.  

PubMed

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

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

2013-03-10

182

Cardiac conditions.  

PubMed

Cardiovascular disease (CVD) is the leading cause of death in the US. The growth of the older population in coming decades will inevitably increase the incidence of age-related cardiac disease. Increasing evidence has shown the prevalence of co-morbid mental health conditions in CVD patients. Specifically, depression and anxiety have been linked with CVD mortality. Due to the risk of psychosocial conditions with cardiac patients, mental health practitioners in health and gerontology need to be well-informed about CVD-related mental health comorbidity and current research developments. Accordingly, this article provides a systematic review of the clinical evidence about the efficacy, cost-effectiveness, and any potential risk of psychosocial intervention with cardiac patients. PMID:18924386

Peck, Michel D; Ai, Amy L

2008-01-01

183

Dipyridamole cardiac imaging  

SciTech Connect

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

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

1988-02-01

184

Cardiac angiosarcoma.  

PubMed

Angiosarcoma is one of the most common cardiac tumors, but early detection of this tumor is often difficult, as exemplified by our patient, a 55-year-old woman whose cardiac tumor was first detected by echocardiography. Surgical removal of the tumor was impossible due to its extensive pericardial invasion. Pathological diagnosis was not complete before autopsy because of the wide occupied necrotized area of the tumor. There is no diagnostic imaging technique available to detect such a necrotized area. An imaging technique more powerful than echocardiography and able to diagnose angiosarcoma earlier is needed. PMID:8933189

Ohtahara, A; Hattori, K; Fukuki, M; Hirata, S; Ahmmed, G U; Kato, M; Fujimoto, Y; Shigemasa, C; Mashiba, H

1996-10-01

185

Setting and maintaining  

E-print Network

Setting and maintaining boundaries within the context of attachment relationships Menna Thomas-child relationship'? 2. What are `boundaries' and how to set and maintain them? 3. Different ways of coping ·Traditional behaviour principles of reinforcement and conditioning ·Impact of family social setting on parent

Harman, Neal.A.

186

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

SciTech Connect

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)? 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.

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

2010-07-02

187

Cardiac optogenetics.  

PubMed

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

Entcheva, Emilia

2013-05-01

188

Cardiac optogenetics  

PubMed Central

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

2013-01-01

189

Cardiac Surgery  

PubMed Central

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

Weisse, Allen B.

2011-01-01

190

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

PubMed

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

Nelson, O Lynne; Rourke, Bryan C

2013-12-15

191

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

PubMed Central

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

Nelson, O. Lynne; Rourke, Bryan C.

2013-01-01

192

Maintaining Plant Genebanks  

NSDL National Science Digital Library

This lesson explores the benefits and problems of maintaining plant genebanks globally. Students can plan a genebank or agricultural cryopreservation business venture, write a biography about a famous botanist, present views at a genebank symposium for developing nations and more!

Brian R. Shmaefsky (Kingwood College; )

2003-06-02

193

Prophylactic intravenous use of milrinone after cardiac operation in pediatrics (PRIMACORP) study  

Microsoft Academic Search

Background Many pediatric patients undergoing cardiac surgery involving cardiopulmonary bypass have a predictable fall in the cardiac index 6 to18 hours after surgery, the so-called low cardiac output syndrome (LCOS). Because patients who have LCOS require more monitoring and support and have a prolonged stay in the intensive care unit, the syndrome is associated with a costly morbidity. Milrinone, a

Timothy M. Hoffman; Gil Wernovsky; Andrew M. Atz; James M. Bailey; Akbar Akbary; John F. Kocsis; David P. Nelson; Anthony C. Chang; Thomas J. Kulik; Thomas L. Spray; David L. Wessel

2002-01-01

194

Tapping the brake on cardiac growth-endogenous repressors of hypertrophic signaling-  

Microsoft Academic Search

Cardiac hypertrophy is considered an early hallmark during the clinical course of heart failure and an important risk factor for cardiac morbidity and mortality. Although hypertrophy of individual cardiomyocytes in response to pathological stimuli has traditionally been considered as an adaptive response required to sustain cardiac output, accumulating evidence from studies in patients and animal models suggests that in most

Joost J. Leenders; Yigal M. Pinto; Esther E. Creemers

2011-01-01

195

Sudden Cardiac Arrest  

MedlinePLUS

... the NHLBI on Twitter. What Is Sudden Cardiac Arrest? Sudden cardiac arrest (SCA) is a condition in which the heart ... This Content: Next >> April 1, 2011 Sudden Cardiac Arrest Clinical Trials Clinical trials are research studies that ...

196

Cardiac pacemakers: an update.  

PubMed

In this update of cardiac pacing we review the new revised ACC/AHA/NASPE Guidelines for implantation of cardiac pacemakers, including selection of pacing mode, possible new indications, and other more recent advances in cardiac pacing. PMID:15008358

Johnson, Charles D; Arzola-Castañer, Daniel

2003-01-01

197

Cardiac Syndrome X  

MedlinePLUS

... What causes cardiac syndrome X? There are many theories about what causes cardiac syndrome X. Some doctors ... disease. How is cardiac syndrome X treated? A number of medicines can help relieve the angina pain ...

198

Cardiac Rehabilitation in Older Cardiac Patients  

Microsoft Academic Search

Cardiac rehabilitation services are comprehensive, long-term programs involving medical evaluation, prescribed exercise,\\u000a cardiac risk factor modification, education and counseling. These programs are designed to limit the physiologic and psychologic\\u000a effects of cardiac illness, reduce the risk for sudden death or reinfarction, control cardiac symptoms, stabilize or reverse\\u000a the atherosclerotic process, and enhance the psychosocial and vocational status of patients with

Philip A. Ades

199

Central Venous Saturation: A Prognostic Tool in Cardiac Surgery patients  

Microsoft Academic Search

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

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

2010-01-01

200

Visualization of Model Output  

NSDL National Science Digital Library

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

201

Maintaining Medicinal Plant Germplasm  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

202

August 2008 Maintained by  

E-print Network

TELEPHONE DIRECTORY August 2008 Maintained by: Information Systems & Technology 22222 #12 listed below or any activity that you feel is unusual may be the sign of criminal activity. Do you may do so. a scream or call for help the sound of a whistle or loud horn a strange vehicle

Le Roy, Robert J.

203

Vasomotor sympathetic neural control is maintained during sustained upright posture in humans  

PubMed Central

Vasomotor sympathetic activity plays an important role in arterial pressure maintenance via the baroreflex during acute orthostasis in humans. If orthostasis is prolonged, blood pressure may be supported additionally by humoral factors with a possible reduction in sympathetic baroreflex sensitivity. We tested the hypothesis that baroreflex control of muscle sympathetic nerve activity (MSNA) decreases during prolonged upright posture. MSNA and haemodynamics were measured supine and during 45 min 60 deg upright tilt in 13 healthy individuals. Sympathetic baroreflex sensitivity was quantified using the slope of the linear correlation between MSNA and diastolic pressure during spontaneous breathing. It was further assessed as the relationship between MSNA and stroke volume, with stroke volume derived from cardiac output (C2H2 rebreathing) and heart rate. Total peripheral resistance was calculated from mean arterial pressure and cardiac output. We found that MSNA increased from supine to upright (17 ± 8 (s.d.) versus 38 ± 12 bursts min?1; P < 0.01), and continued to increase to a smaller degree during sustained tilt (39 ± 11, 41 ± 12, 43 ± 13 and 46 ± 15 bursts min?1 after 10, 20, 30 and 45 min of tilt; between treatments P < 0.01). Sympathetic baroreflex sensitivity increased from supine to upright (?292 ± 180 versus ?718 ± 362 units beat?1 mmHg?1; P < 0.01), but remained unchanged as tilting continued (?611 ± 342 and ?521 ± 221 units beat?1 mmHg?1 after 20 and 45 min of tilt; P = 0.49). For each subject, changes in MSNA were associated with changes in stroke volume (r = 0.88 ± 0.13, P < 0.05), while total peripheral resistance was related to MSNA during 45 min upright tilt (r = 0.82 ± 0.15, P < 0.05). These results suggest that the vasoconstriction initiated by sympathetic adrenergic nerves is maintained by ongoing sympathetic activation during sustained (i.e. 45 min) orthostasis without obvious changes in vasomotor sympathetic neural control. PMID:17008377

Fu, Qi; Shook, Robin P; Okazaki, Kazunobu; Hastings, Jeffrey L; Shibata, Shigeki; Conner, Colin L; Palmer, M Dean; Levine, Benjamin D

2006-01-01

204

Cardiac Cells Beating in Culture: A Laboratory Exercise  

ERIC Educational Resources Information Center

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

Weaver, Debora

2007-01-01

205

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

PubMed Central

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

Cabrales, Pedro

2014-01-01

206

Acoustic Levitator Maintains Resonance  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

207

Direct bonded space maintainers.  

PubMed

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. PMID:8217886

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

1993-01-01

208

Cardiac matrix: a clue for future therapy  

PubMed Central

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

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

2014-01-01

209

Linear output nitinol engine  

SciTech Connect

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

Banks, R.M.

1986-01-14

210

Extracellular Matrix Roles During Cardiac Repair  

PubMed Central

The cardiac extracellular matrix (ECM) provides a platform for cells to maintain structure and function, which in turn maintains tissue function. In response to injury, the ECM undergoes remodeling that involves synthesis, incorporation, and degradation of matrix proteins, with the net outcome determined by the balance of these processes. The major goals of this review are a) to serve as an initial resource for students and investigators new to the cardiac ECM remodeling field, and b) to highlight a few of the key exciting avenues and methodologies that have recently been explored. While we focus on cardiac injury and responses of the left ventricle (LV), the mechanisms reviewed here have pathways in common with other wound healing models. PMID:20670633

Jourdan-LeSaux, Claude; Zhang, Jianhua; Lindsey, Merry L.

2010-01-01

211

Cardiac pearls.  

PubMed

Most diagnoses of cardiovascular disease are made in the office or at the bedside. For example, in pulsus alternans of the radial pulse, observed when first greeting a patient, alteration of intensity of the second sound and systolic murmur and a ventricular (S3) gallop are clinical pearls--often subtle--that diagnose cardiac decompensation. A faint gallop, ventricular (S3) or atrial (S4), might be overlooked in a patient who has an emphysematous chest and an increase in anteroposterior diameter if one listens over the usual areas of the precordium. However, the gallop might be detected easily by listening over the xiphoid or epigastric area. How do you tell the difference between an S4, a split first sound, and an ejection sound? The S4 is eliminated with pressure on the stethoscope, but pressure does not eliminate the ejection sound or the splitting of S1. The atrial sound (S4) is most frequently found in patients who have coronary heart disease, and it is a constant finding in patients who have hypertension. It does not denote heart failure, as does the S3 (ventricular) gallop. In some patients, both atrial (S4) and ventricular (S3) diastolic gallops may be present. This occurrence is common in patients with cardiac decompensation associated with coronary heart disease, hypertensive heart disease, and dilated cardiomyopathy. When these diastolic filling sounds occur in close proximity, a short rumbling murmur may be heard, which causes confusion of this sound with that of a valvular or congenital lesion. When both sounds occur exactly simultaneously, a single sound results. Often, this sound is louder than either the first or second sound and can be misinterpreted as either a valvular or congenital lesion. This, however, is a summation gallop, which is rare. For the most accurate timing of heart sounds and murmurs, the simple technique called "inching" is the best. Keeping the second sound in mind as a reference, the physician moves (inches) the stethoscope from the aortic area to the apex. An extra sound may be noted to occur in systole before the second sound, thereby diagnosing a systolic click. If the sound occurs after the second sound, however, it is an S3 or ventricular diastolic gallop. If a murmur appears before S2, it is a systolic murmur; if it appears after S2, it is a diastolic murmur. When the Austin-Flint murmur is heard, significant aortic regurgitation exists.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8306847

Harvey, W P

1994-02-01

212

Cardiac decompression after operation for congenital heart disease in infancy.  

PubMed

Between January 1987 and July 1992, 641 infants (less than 1 year of age) underwent cardiac surgical procedures through a median sternotomy incision at the UCLA Medical Center. In 36 (5.6%), to achieve cardiac decompression, the chest was left open after the operation, or was re-opened immediately postoperatively because of low cardiac output. The incidence of cardiac decompression was 31% (4/13) after the Norwood procedure and 24% (7/29) after truncus arteriosus repair. Opening of the chest reduced intrathoracic pressure and allowed complete expansion of the lungs. Delayed sternal closure was carried out in 27 patients at a mean of 5 days (range, 2 to 14 days) postoperatively. By the time of chest closure, left atrial pressure had decreased from a mean of 12 +/- 1.4 to 8.4 +/- 0.8 mm Hg (p < 0.004), and inotropic drug support with dopamine and dobutamine had also decreased significantly. Thirteen (36%) patients died of low cardiac output and multiorgan failure (4 of them after delayed chest closure) that was complicated by sepsis in 2. The incidence of sternal wound infection was relatively low at 5.6% (2/36); 1 patient died of generalized sepsis complicating multiorgan failure and the second case occurred in a patient who survived long term after sternectomy. With optimal ventilatory and inotropic drug support and meticulous wound care, delayed sternal closure may improve the survival of infants in low cardiac output after cardiac surgical procedures. PMID:7979665

Elami, A; Permut, L C; Laks, H; Drinkwater, D C; Sebastian, J L

1994-11-01

213

Diodes stabilize LED output  

NASA Technical Reports Server (NTRS)

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.

Deters, R. A.

1977-01-01

214

AN INTEGRATEDMICROELECTROMECHANICALRESONANT OUTPUT GYROSCOPE -  

E-print Network

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

Tang, William C

215

Dome pressure maintaining valve  

SciTech Connect

This patent describes a system for maintaining dome fluid pressure in a pilot operated relief valve. It comprises: a fluid pressure maintenance means having an inlet port for receiving pressurized fluid supply from a source requiring pressure relief maintenance and an outlet port for expelling the pressurized fluid from the fluid pressure maintenance means; the fluid pressure maintenance means being placed in a circuit between a sensor inlet and the pilot valve, means capable of being adapted with fixed or adjustable pressure setting functionality; the fluid pressure maintenance means outlet port in communication with a dome of the relief valve through the pilot; the fluid pressure maintenance means functioning through a poppet check valve for equalizing inlet and outlet pressure. The poppet check valve providing inlet flow and check for reverse flow; the poppet check valve and a piston valve integrated into one piston valve embodiment with the piston valve providing outlet flow in a backflow relief mode; and the fluid pressure maintenance means having a pressure storage chamber for providing a maintaining fluid pressure in the relief valve dome.

Snyder, D.E.

1990-12-04

216

Reagan: Maintain Antarctic program  

NASA Astrophysics Data System (ADS)

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.

Richman, Barbara T.

217

Cardiac conduction system  

MedlinePLUS Videos and Cool Tools

... cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components ... the cardiac conduction system’s electrical activity in the heart.

218

Cardiac sodium channelopathies  

Microsoft Academic Search

Cardiac sodium channel are protein complexes that are expressed in the sarcolemma of cardiomyocytes to carry a large inward\\u000a depolarizing current (INa) during phase 0 of the cardiac action potential. The importance of INa for normal cardiac electrical activity is reflected by the high incidence of arrhythmias in cardiac sodium channelopathies,\\u000a i.e., arrhythmogenic diseases in patients with mutations in SCN5A,

Ahmad S. Amin; Alaleh Asghari-Roodsari; Hanno L. Tan

2010-01-01

219

Maintaining proper dental records.  

PubMed

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

Leeuw, Wilhemina

2014-01-01

220

Echocardiography in cardiac amyloidosis.  

PubMed

Echocardiography is the most widely used noninvasive test in patients with heart failure or abnormal cardiac findings on examination. Patients with amyloidosis may have significant cardiac abnormalities, several of which are highly suggestive of the disease. This article reviews echocardiographic features found in cardiac amyloidosis. PMID:25597027

Falk, Rodney H; Quarta, C Cristina

2015-03-01

221

ADAS Update and Maintainability  

NASA Technical Reports Server (NTRS)

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.

Watson, Leela R.

2010-01-01

222

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

SciTech Connect

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.

Yasuda, Yoshikazu; Fukushima, Yuji; Kaneki, Masao [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States)] [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States); Martyn, J.A. Jeevendra, E-mail: jmartyn@partners.org [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States)] [Department of Anaesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Shriners Hospitals for Children, Harvard Medical School, Boston, MA 02114 (United States)

2013-02-01

223

Cardiac Trauma: Clinical and Experimental Correlations of Myocardial Contusion  

PubMed Central

Clinical and experimental observations in myocardial contusion have been correlated. Cardiac arrhythmia is always an important consequence and may be fatal. Reduction in cardiac output often accompanies significant cardiac injury. The coronary arterial circulation is not interrupted and is generally enhanced to the area of injury. Healing of the injury under these circulatory conditions may result in patchy scarring and peculiar adynamic areas of myocardium. Early diagnosis of myocardial contusion may be aided using radionuclide imaging with 99mTc-Sn-polyphosphate. ImagesFig. 1.Fig. 2.Fig. 3.Fig. 4.Fig. 5.Fig. 6.Fig. 7.Fig. 8. PMID:4412327

Doty, Donald B.; Anderson, Alan E.; Rose, Earl F.; Go, Raymundo T.; Chiu, Chiang L.; Ehrenhaft, J. L.

1974-01-01

224

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

SciTech Connect

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

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

1985-01-01

225

Diabetes influences cardiac extracellular matrix remodelling after myocardial infarction and subsequent development of cardiac dysfunction  

PubMed Central

This study was conducted to examine the influence of acute streptozotocin-induced diabetes on cardiac remodelling and function in mice subjected to myocardial infarction (MI) by coronary artery ligation. Echocardiography analysis indicated that diabetes induced deleterious cardiac functional changes as demonstrated by the negative differences of ejection fraction, fractional shortening, stroke volume, cardiac output and left ventricular volume 24 hrs after MI. Temporal analysis for up to 2 weeks after MI showed higher mortality in diabetic animals because of cardiac wall rupture. To examine extracellular matrix remodelling, we used fluorescent molecular tomography to conduct temporal studies and observed that total matrix metalloproteinase (MMP) activity in hearts was higher in diabetic animals at 7 and 14 days after MI, which correlated well with the degree of collagen deposition in the infarct area visualized by scanning electron microscopy. Gene arrays indicated temporal changes in expression of distinct MMP isoforms after 1 or 2 weeks after MI, particularly in diabetic mice. Temporal changes in cardiac performance were observed, with a trend of exaggerated dysfunction in diabetic mice up to 14 days after MI. Decreased radial and longitudinal systolic and diastolic strain rates were observed over 14 days after MI, and there was a trend towards altered strain rates in diabetic mouse hearts with dyssynchronous wall motion clearly evident. This correlated with increased collagen deposition in remote areas of these infarcted hearts indicated by Masson's trichrome staining. In summary, temporal changes in extracellular matrix remodelling correlated with exaggerated cardiac dysfunction in diabetic mice after MI. PMID:22862852

Eguchi, Megumi; Xu, Guoxiong; Li, Ren-Ke; Sweeney, Gary

2012-01-01

226

Morphological studies of the cardiac lymphatic system.  

PubMed

The distribution and structure of the mammalian cardiac lymphatic system have been investigated by puncture injection, intra-arterial injection of silver nitrate, hydrogen peroxide immersion, and light and electron microscopy. The cardiac lymphatic system consists of drainage vessels and lymphatic capillaries. The drainage vessels contain many valves and are mainly situated subepicardially following branches of the coronary artery. The lymphatic capillaries are composed of a thin layer of endothelial cells, and form relatively dense networks in a fishnet arrangement. These lymphatic networks are richer in the ventricles than in the atria, being present in the subepicardial myocardial and subendocardial regions. In addition, networks are found in all cusps of the atrioventricular valves, and in the sinuatrial node and atrioventricular system. The lymphatic system maintains cardiac homeostasis by receiving proteins, electrolytes and excess fluid from the interstitial tissue and returning them to the venous system. PMID:2252624

Shimada, T; Morita, T; Oya, M; Kitamura, H

1990-01-01

227

4D iterative reconstruction in cardiac CT  

NASA Astrophysics Data System (ADS)

In this paper, a 4D iterative reconstruction scheme is developed to improve noise characteristics and/or reduce radiation exposure in multi-slice cardiac CT. In our implementation, image volume datasets are reconstructed at adjacent temporal positions with respect to an optimized cardiac phase (best phase). Nonlinear regularization priors operate on a 4D cube surrounding each voxel in 4D space, reducing image noise while maintaining temporal and spatial image sharpness. The temporal resolution of image data is maintained despite the usage of temporal data that can substantially exceed the reconstruction range of the 'best phase' reconstruction. Consequently, the noise statistics is significantly improved because non-correlated image data at different temporal positions are utilized. To reduce the high computational load, the iterative regularization in 4D can be transferred into image space. Raw data based Iterative Reconstruction reducing artifacts due to the non-exactness of the backprojector is decoupled from regularization and restricted to only those projection data belonging to the 'best phase' reconstruction. Finally, the image formation is achieved by a normalized combination of the low frequency part of the raw data based Iterative Reconstruction at cardiac best phase and the high frequency part of the image based regularization image at best phase. We demonstrate the potential of noise reduction on basis of clinical cardiac CT data. As an example for cardiac dual source CT (DSCT) data a noise reduction up to 70% was achieved. Even in case of a very high and irregular heart beat with an average heart rate of 115 bpm the high temporal resolution of DSCT could be maintained.

Bruder, H.; Raupach, R.; Allmendinger, T.; Sunnegårdh, J.; Stierstorfer, K.; Flohr, T.

2012-03-01

228

Cardiac Magnetic Resonance Imaging  

Microsoft Academic Search

Magnetic resonance imaging (MRI) has proven to be extremely versatile and useful for studying cardiac anatomy and function,\\u000a both for providing a deeper understanding of cardiac physiology and as a means to diagnose cardiac diseases. The capabilities\\u000a of MRI as a tomographic imaging modality to capture, with high spatial resolution, the anatomy of 3D structures was already\\u000a well appreciated before

Michael Jerosch-Herold; Ravi Teja Seethamraju; Carsten Rickers

229

Increasing Photocathode Charge Output  

SciTech Connect

A fundamental concern in the operation of electron accelerators is the generation of intense beams with high polarization. The time structure of the electron beam determines whether the limiting factor in emission is laser power or surface charge buildup. The presence of excess surface charge comes about due to the photon absorption that excites electrons from the valence to the conduction band. Some fraction of the electrons can be trapped near the surface which induces a rise in the electron affinity through the increased electrostatic potential. The higher affinity causes a lower emission probability and thus less emitted charge at later times. The electron affinity can recover to the zero charge limit after electron-hole recombination. As an example, the Next Linear Collider requires 95 micropulses having 2 x 10{sup 10} electrons per pulse in 0.7 ns with an interpulse spacing of 2.8 ns. Experience at SLAC has shown it is possible to generate 16 x 10{sup 10} electrons in 2 ns pulses with the requisite polarization. However, subsequent pulses may experience strong intensity damping. Several parameters can be varied to enhance the net charge output of the later pulses. Among these are increasing either the electric field at the photocathode surface or the surface charge dissipation rate by raising the carrier concentration or shunting the trapped charge. We present a series of measurements and a phenomenological model to characterize the range of these influences.

Mulhollan, Gregory A

1999-10-19

230

Cardiac stem cell niches.  

PubMed

The critical role that stem cell niches have in cardiac homeostasis and myocardial repair following injury is the focus of this review. Cardiac niches represent specialized microdomains where the quiescent and activated state of resident stem cells is regulated. Alterations in niche function with aging and cardiac diseases result in abnormal sites of cardiomyogenesis and inadequate myocyte formation. The relevance of Notch1 signaling, gap-junction formation, HIF-1? and metabolic state in the regulation of stem cell growth and differentiation within the cardiac niches are discussed. PMID:25267073

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

2014-11-01

231

Hippo pathway effector Yap promotes cardiac regeneration  

PubMed Central

The adult mammalian heart has limited potential for regeneration. Thus, after injury, cardiomyocytes are permanently lost, and contractility is diminished. In contrast, the neonatal heart can regenerate owing to sustained cardiomyocyte proliferation. Identification of critical regulators of cardiomyocyte proliferation and quiescence represents an important step toward potential regenerative therapies. Yes-associated protein (Yap), a transcriptional cofactor in the Hippo signaling pathway, promotes proliferation of embryonic cardiomyocytes by activating the insulin-like growth factor and Wnt signaling pathways. Here we report that mice bearing mutant alleles of Yap and its paralog WW domain containing transcription regulator 1 (Taz) exhibit gene dosage-dependent cardiac phenotypes, suggesting redundant roles of these Hippo pathway effectors in establishing proper myocyte number and maintaining cardiac function. Cardiac-specific deletion of Yap impedes neonatal heart regeneration, resulting in a default fibrotic response. Conversely, forced expression of a constitutively active form of Yap in the adult heart stimulates cardiac regeneration and improves contractility after myocardial infarction. The regenerative activity of Yap is correlated with its activation of embryonic and proliferative gene programs in cardiomyocytes. These findings identify Yap as an important regulator of cardiac regeneration and provide an experimental entry point to enhance this process. PMID:23918388

Xin, Mei; Kim, Yuri; Sutherland, Lillian B.; Murakami, Masao; Qi, Xiaoxia; McAnally, John; Porrello, Enzo R.; Mahmoud, Ahmed I.; Tan, Wei; Shelton, John M.; Richardson, James A.; Sadek, Hesham A.; Bassel-Duby, Rhonda; Olson, Eric N.

2013-01-01

232

Experimental Control of Cardiac Muscle Alternans  

NASA Astrophysics Data System (ADS)

We demonstrate that alternans in small pieces of in vitro paced bullfrog (Rana Catesbeiana) myocardium can be suppressed by making minute adjustments to the pacing period in response to real time measurements of the action potential duration. Control is possible over a large range of physiological conditions over many animals and the self-referencing control protocol can automatically adjust to changes in the pacing interval. Our results suggest the feasibility of developing low-energy methods for maintaining normal cardiac function.

Hall, G. Martin; Gauthier, Daniel J.

2002-05-01

233

On Maintaining Concentration Neil Tennant  

E-print Network

@jstor.org. http://www.jstor.org Tue Mar 18 17:37:32 2008 #12;On Maintaining Concentration Peter Milne (this issue, then, can be done to save the situation in the light of Milne's counterexample? The sequent that Milne: (y) Maintain Concentration! What Milne has shown is that concentration lapsed when I formulated

Tennant, Neil

234

Lightweight multiple output converter development  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

235

Cardiac effects of 3-iodothyronamine: a new aminergic system modulating cardiac function  

Microsoft Academic Search

iodothyronamine T1AM is a novel en- dogenous thyroid hormone derivative that activates the G protein-coupled receptor known as trace anime- associated receptor 1 (TAAR1). In the isolated working rat heart and in rat cardiomyocytes, T1AM produced a reversible, dose-dependent negative inotropic effect (e.g. ,2 75, 513, and 652% decrease in cardiac output at 19, 25, and 38 M concentration, respec-

Grazia Chiellini; Sabina Frascarelli; Sandra Ghelardoni; Vittoria Carnicelli; Sandra C. Tobias; Andrea DeBarber; Simona Brogioni; Simonetta Ronca-Testoni; Elisabetta Cerbai; David K. Grandy; Thomas S. Scanlan; Riccardo Zucchi

2007-01-01

236

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

NASA Astrophysics Data System (ADS)

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

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

2005-10-01

237

Serial Input Output  

SciTech Connect

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

Waite, Anthony; /SLAC

2011-09-07

238

Postgraduate in Cardiac Electrophysiology  

E-print Network

and myocardial infarction), · Diseases affecting the mechanical function of the heart (heart failure), · Diseases by an acute obstruction of a coronary artery can cause acute heart failure and acute arrhythmias that may lead to cardiogenic shock or sudden cardiac death. Cardiac arrhythmias can also cause heart failure and heart failure

Einmahl, Uwe

239

What Is Cardiac Rehabilitation?  

MedlinePLUS

... if your doctor says you can. • Have your heart rate, blood pressure and EKG monitored. A cardiac rehabilitation (rehab) program takes place in a hospital or in the community. Cardiac rehab is for patients who are getting better after heart problems or surgery. One of the best things ...

240

Prospectively gated cardiac CT  

Microsoft Academic Search

Future cardiac CT protocols will utilize large area detectors with whole heart scans performed within one heartbeat. For such scans, accurate prospective ECG gating is essential to capture the heart at the correct phase. This report addresses one of the main factors affecting the prospective gating accuracy: the ability to predict the cardiac phase from the ECG signal. Two different

Dominic Heuscher; S. Zabic

2007-01-01

241

Cardiac risk telemonitoring  

Microsoft Academic Search

Utilization of advanced information, telecommunication and implant technology for cardiac risk stratification and management is one of the greatest challenges for modern health care provision. Sudden cardiac death is the major contributor to overall cardiovascular mortality with approximately 60% of all coronary heart disease fatalities occurring annually. Although some high-risk patient groups have been identified with reasonable sensitivity and specificity

H. Hutten; M. Hribernigg; G. Rauchegger

2001-01-01

242

Garfinkel Cardiac Data  

NSDL National Science Digital Library

Cardiac data on multiple variables for a selected population of 220 men and 338 women participating in a drug treatment study of dobutamine for heart attack prevention. Garfinkel, Alan, et. al. "Prognostic Value of Dobutamine Stress Echocardiography in Predicting Cardiac Events in Patients With Known or Suspected Coronary Artery Disease." Journal of the American College of Cardiology 33.3 (1999) 708-16.

Alan Garfinkel (University of California Los Angeles; Physiological Sci/Med-Cardio)

2009-01-10

243

Cardiac Resynchronization Therapy Upregulates Cardiac Autonomic Control  

PubMed Central

Objective: To determine the effect of cardiac resynchronization therapy (CRT) on sympathetic nervous function in heart failure (HF). Background: Neurohormonal dysregulation and cardiac autonomic dysfunction are associated with HF and contribute to HF progression and its poor prognosis. We hypothesized that mechanical resynchronization improves cardiac sympathetic function in HF. Methods: Sixteen consecutive patients receiving CRT for advanced cardiomyopathy and 10 controls were included in this prospective study. NYHA class, 6-minute walk distance, echocardiographic parameters, plasma norepinephrine (NE) were assessed at baseline, 3-month and 6-month follow-up. Cardiac sympathetic function was determined by 123iodine metaiodobenzylguanidine (123I-MIBG) scintigraphy and 24-hour ambulatory electrocardiography. Results: Along with improvement in NYHA class (3.1 ± 0.3 to 2.1 ± 0.4, P < 0.001) and LVEF (23 ± 6% to 33 ± 12%, P < 0.001 delayed heart/mediastinum (H/M) 123 I-MIBG ratio increased significantly (1.8 ± 0.7 to 2.1 ± 0.6, P = 0.04) while the H/M 123I-MIBG washout rate decreased significantly (54 ± 25% to 34± 24%, P = 0.01) from baseline to 6-month follow-up. The heart rate variability (HRV) measured in SD of normal-to-normal intervals also increased significantly from baseline (82 ± 30 ms) to follow-up (111 ± 32 ms, P = 0.04). The improvement in NYHA after CRT was significantly associated with baseline 123I-MIBG H/M washout rate (r = 0.65, P = 0.03). The improvement in LVESV index was associated with baseline 123I-MIBG delayed H/M ratio (r = ?0.67, P = 0.02) and H/M washout rate (r = 0.65, P = 0.03). Conclusion: After CRT, improvements in cardiac symptoms and LV function were accompanied by rebalanced cardiac autonomic control as measured by 123I-MIBG and HRV. PMID:18479331

CHA, YONG-MEI; OH, JAE; MIYAZAKI, CHINAMI; HAYES, DAVID L.; REA, ROBERT F.; SHEN, WIN-KUANG; ASIRVATHAM, SAMUEL J.; KEMP, BRAD J.; HODGE, DAVID O.; CHEN, PENG-SHENG; CHAREONTHAITAWEE, PANITHAYA

2009-01-01

244

Cardiac Hegemony of Senescence  

PubMed Central

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

Siddiqi, Sailay; Sussman, Mark A.

2013-01-01

245

Corticospinal drive during painful voluntary contractions at constant force output  

Microsoft Academic Search

In the voluntary contractions, output force can be maintained constant although the inhibitory influences exerted by pain on muscle activity. We investigated changes in the spontaneous and evoked activity of the abductor digiti minimi muscle (ADM) and the biceps brachii muscle (BIC) in healthy volunteers during constant force noxious contraction, resulting from chemically activated nociceptive afferents. EMG–force relationship, motor-evoked response

Francesco Del Santo; Francesca Gelli; Raffaele Spidalieri; Alessandro Rossi

2007-01-01

246

Trichloroethylene Exposure during Cardiac Valvuloseptal Morphogenesis Alters Cushion Formation and Cardiac Hemodynamics in the Avian Embryo  

PubMed Central

It is controversial whether trichloroethylene (TCE) is a cardiac teratogen. We exposed chick embryos to 0, 0.4, 8, or 400 ppb TCE/egg during the period of cardiac valvuloseptal morphogenesis (2–3.3 days’ incubation). Embryo survival, valvuloseptal cellularity, and cardiac hemodynamics were evaluated at times thereafter. TCE at 8 and 400 ppb/egg reduced embryo survival to day 6.25 incubation by 40–50%. At day 4.25, increased proliferation and hypercellularity were observed within the atrioventricular and outflow tract primordia after 8 and 400 ppb TCE. Doppler ultrasound revealed that the dorsal aortic and atrioventricular blood flows were reduced by 23% and 30%, respectively, after exposure to 8 ppb TCE. Equimolar trichloroacetic acid (TCA) was more potent than TCE with respect to increasing mortality and causing valvuloseptal hypercellularity. These results independently confirm that TCE disrupts cardiac development of the chick embryo and identifies valvuloseptal development as a period of sensitivity. The hypercellular valvuloseptal profile is consistent with valvuloseptal heart defects associated with TCE exposure. This is the first report that TCA is a cardioteratogen for the chick and the first report that TCE exposure depresses cardiac function. Valvuloseptal hypercellularity may narrow the cardiac orifices, which reduces blood flow through the heart, thereby compromising cardiac output and contributing to increased mortality. The altered valvuloseptal formation and reduced hemodynamics seen here are consistent with such an outcome. Notably, these effects were observed at a TCE exposure (8 ppb) that is only slightly higher than the U.S. Environmental Protection Agency maximum containment level for drinking water (5 ppb). PMID:16759982

Drake, Victoria J.; Koprowski, Stacy L.; Lough, John; Hu, Norman; Smith, Susan M.

2006-01-01

247

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

PubMed

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

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

2014-08-01

248

Maintaining Subsurface Drip Irrigation Systems  

E-print Network

A subsurface drip irrigation system should last more than 20 years if properly maintained. Important maintenance procedures include cleaning the filters, flushing the lines, adding chlorine and injecting acids. Details of these procedures...

Enciso, Juan; Porter, Dana; Bordovsky, Jim; Fipps, Guy

2004-09-07

249

Matrix metalloproteinase expression in cardiac myocytes following myocardial infarction in the rabbit  

Microsoft Academic Search

Myocardial infarction (MI), leads to cardiac remodeling, thinning of the ventricle wall, ventricular dilation, and heart failure, and is a leading cause of death. Interactions between the contractile elements of the cardiac myocytes and the extracellular matrix (ECM) help maintain myocyte alignment required for the structural and functional integrity of the heart. Following MI, reorganization of the ECM and the

Anne M. Romanic; Cynthia L. Burns-Kurtis; Bernard Gout; Isabelle Berrebi-Bertrand; Eliot H. Ohlstein

2001-01-01

250

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

PubMed Central

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

Buczinski, Sébastien; Boulay, Guillaume; DesCôteaux, Luc

2011-01-01

251

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

PubMed Central

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

Kimura, Wataru

2012-01-01

252

Enhanced performance CCD output amplifier  

DOEpatents

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.

Dunham, Mark E. (Los Alamos, NM); Morley, David W. (Santa Fe, NM)

1996-01-01

253

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

PubMed

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

Little, Alexander G; Seebacher, Frank

2014-03-01

254

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

PubMed Central

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 ?m2) 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 ?g/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

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

2013-01-01

255

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

PubMed

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 ?m(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 ?g/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

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

2014-03-01

256

Molecular Basis of Cardiac Myxomas  

PubMed Central

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

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

2014-01-01

257

Effects of Lifestyle Modification Programs on Cardiac Risk Factors  

PubMed Central

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

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

2014-01-01

258

Effects of lifestyle modification programs on cardiac risk factors.  

PubMed

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

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

2014-01-01

259

Low dose applications of lightspeed VCT in cardiac imaging  

NASA Astrophysics Data System (ADS)

We introduced and evaluated the techniques LightSpeed VCT uses to reduce X-ray dose and image noise in cardiac helical CT applications. These techniques include the use of much improved VCT data acquisition system (VDAS) with reduced electronic noise; cardiac bowtie that redistributes X-rays to have more signals for heart and much less flux to the peripheries; adaptive post-processing filters to reduce cardiac image noise; and ECG modulated tube currents to concentrate X-ray dose for desired cardiac phases. Phantom and patient scans were used to evaluate the dose saving and noise reduction potentials of these techniques. The results demonstrated that the improved VDAS reduced image noise 15-20% for cardiac imaging. With same scan technique, the use of cardiac bowtie reduced about 10% dose in terms of CTDIw measurement and clinical evaluation demonstrated additional 7% image noise reduction and equivalent image quality with cardiac bowtie vs. regular body bowtie. The adaptive filter generated 15-20% noise reduction while maintaining image resolution and artery sharpness. Finally, the use of ECG modulated mA method provided up to 50% dose reduction based on CTDIw measurements, but the saving potentials depended on the heart rate and cardiac phase selection. For heart rate of 60bpm and +/-15% cardiac phase margin, the average dose reduction could be 30%. Since these dose and noise reduction methods are inclusive and can be combined to produce even greater dose/noise reduction. It is reasonable to believe that with VCT we maybe able to acquire cardiac helical CT images with only 30-40% of the dose of older generation 16-slice CT scanners with similar noise level and same slice thickness.

Li, Jianying; Hsieh, Jiang; Lundgren, Ronald; Shen, Yun

2007-03-01

260

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

PubMed

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

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

2015-01-01

261

Cardiac Applications for Human Pluripotent Stem Cells  

PubMed Central

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

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

2010-01-01

262

Cardiac muscle cells  

NSDL National Science Digital Library

Cardiac muscles are found only in the heart. They work together to bring deoxygenated blood in and push oxygenated blood out into the body. Essentially, they keep your heart pumping and your body alive.

Nathanael Reveal (None; )

2007-07-02

263

[Drugs for cardiac arrest].  

PubMed

After publication of the 2005 international recommendations on resuscitation, a French panel of experts on cardiac arrest published guidelines adapted to French practice. Despite the absence of placebo-controlled trials, adrenaline remains the standard vasopressor for cardiac arrest, at a dose of 1 mg about every 4 minutes. Amiodarone has replaced lidocaine in treatment of refractory ventricular fibrillation.No other drug is indicated during cardiopulmonary resuscitation,except for particular causes of cardiac arrest. Fibrinolysis should be considered only for cardiac arrest due to pulmonary embolism. Isotonic saline solution is recommended for infusions, and routine administration of sodium bicarbonate is not recommended. Intravenous access is necessary, but when unavailable rapidly,intraosseous is preferred to endotracheal delivery in adults and children PMID:18434074

Gueugniaud, Pierre-Yves; David, Jean-Stéphane; Dubien, Pierre-Yves

2008-06-01

264

Primary Cardiac Angiofibroma  

PubMed Central

Cardiac Angiofibroma is an uncommon intracardiac tumor. Thus far, only 4 cases of the rare intracardiac tumor have been reported. The present case-report describes an intracardiac angiofibroma in a 57-year-old healthy female. The patient was incidentally diagnosed with a left ventricle mass during echocardiography. We performed cardiac imaging, surgical excision and histological evaluation of the mass. The angiofibroma demonstrated features different from the relatively common cardiac tumors such as fibroma, myxoma and angiosarcoma. The cardiac MRI showed slightly high signal intensity on both T1 and T2, with the central core of lower signal intensity. The resected tumor was a whitish and rubbery mass. Histologically, the tumor showed the benign vascular proliferations associated with the surrounding collagen deposition. PMID:24174966

Kim, Young Ju; Kim, Young Jin; Kim, Se Hoon; Youn, Young-Nam

2013-01-01

265

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) ...

266

Autonomic cardiac innervation  

PubMed Central

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

Hasan, Wohaib

2013-01-01

267

Measuring Air-Ionizer Output  

NASA Technical Reports Server (NTRS)

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.

Lonborg, J. O.

1985-01-01

268

Predictive value of the stomach wall pH for complications after cardiac operations: comparison with other monitoring  

Microsoft Academic Search

The ability to predict impending complications after elective cardiac operations from measurements of BP, cardiac index, arterial pH, and urine output on the day of operation was compared with that of indirect measurement of stomach wall pH in 85 patients. We found that acidosis in the stomach wall was the most sensitive predictor for complications. The specificity of this predictive

Richard G. Fiddian-Green; Stephen P. Baker

1987-01-01

269

Abnormal Cardiac Autonomic Regulation in Mice Lacking ASIC3  

PubMed Central

Integration of sympathetic and parasympathetic outflow is essential in maintaining normal cardiac autonomic function. Recent studies demonstrate that acid-sensing ion channel 3 (ASIC3) is a sensitive acid sensor for cardiac ischemia and prolonged mild acidification can open ASIC3 and evoke a sustained inward current that fires action potentials in cardiac sensory neurons. However, the physiological role of ASIC3 in cardiac autonomic regulation is not known. In this study, we elucidate the role of ASIC3 in cardiac autonomic function using Asic3?/? mice. Asic3?/? mice showed normal baseline heart rate and lower blood pressure as compared with their wild-type littermates. Heart rate variability analyses revealed imbalanced autonomic regulation, with decreased sympathetic function. Furthermore, Asic3?/? mice demonstrated a blunted response to isoproterenol-induced cardiac tachycardia and prolonged duration to recover to baseline heart rate. Moreover, quantitative RT-PCR analysis of gene expression in sensory ganglia and heart revealed that no gene compensation for muscarinic acetylcholines receptors and beta-adrenalin receptors were found in Asic3?/? mice. In summary, we unraveled an important role of ASIC3 in regulating cardiac autonomic function, whereby loss of ASIC3 alters the normal physiological response to ischemic stimuli, which reveals new implications for therapy in autonomic nervous system-related cardiovascular diseases. PMID:24804235

Cheng, Ching-Feng; Kuo, Terry B. J.; Chen, Wei-Nan

2014-01-01

270

Maintaining Sustainability for Green Schools  

ERIC Educational Resources Information Center

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…

Kennedy, Mike

2011-01-01

271

LEARN TO BUILD AND MAINTAIN  

E-print Network

of person we are. There is no such thing as a perfect relationship. We do much better when we can accept meaningful relationships and interests exist If you are in a romantic relationship you might also likeLEARN TO BUILD AND MAINTAIN HEALTHY RELATIONSHIPS CAPS #12;PLAY As humans we use our relationships

Viglas, Anastasios

272

Cardiac radiology: centenary review.  

PubMed

During the past century, cardiac imaging technologies have revolutionized the diagnosis and treatment of acquired and congenital heart disease. Many important contributions to the field of cardiac imaging were initially reported in Radiology. The field developed from the early stages of cardiac imaging, including the use of coronary x-ray angiography and roentgen kymography, to nowadays the widely used echocardiographic, nuclear medicine, cardiac computed tomographic (CT), and magnetic resonance (MR) applications. It is surprising how many of these techniques were not recognized for their potential during their early inception. Some techniques were described in the literature but required many years to enter the clinical arena and presently continue to expand in terms of clinical application. The application of various CT and MR contrast agents for the diagnosis of myocardial ischemia is a case in point, as the utility of contrast agents continues to expand the noninvasive characterization of myocardium. The history of cardiac imaging has included a continuous process of advances in our understanding of the anatomy and physiology of the cardiovascular system, along with advances in imaging technology that continue to the present day. PMID:25340434

de Roos, Albert; Higgins, Charles B

2014-11-01

273

Cardiac metabolism and arrhythmias  

PubMed Central

Sudden cardiac death remains a leading cause of mortality in the Western world, accounting for up to 20% of all deaths in the U.S.1, 2 The major causes of sudden cardiac death in adults age 35 and older are coronary artery disease (70–80%) and dilated cardiomyopathy (10–15%).3 At the molecular level, a wide variety of mechanisms contribute to arrhythmias that cause sudden cardiac death, ranging from genetic predisposition (rare mutations and common polymorphisms in ion channels and structural proteins) to acquired electrophysiological and structural remodeling in left ventricular hypertrophy and failure.4, 5 A growing body of evidence suggests that altered ion channel function is closely linked to changes in metabolic activity in a wide variety of pathological conditions. In this review we focus on the mechanisms by which altered metabolic function impacts cardiac electrophysiology. We will review the specific molecular targets that allow cardiomyocytes to recognize alterations in their metabolic state and translate this information into changes in membrane excitability in various pathophysiological conditions including ischemia-reperfusion, heart failure (HF), left ventricular hypertrophy, diabetic cardiomyopathy and atrial fibrillation. A comprehensive understanding of the interrelated processes of metabolic and electrical remodeling promises to identify new molecular targets for the treatment of cardiac arrhythmias. PMID:19808483

Barth, Andreas S; Tomaselli, Gordon F

2009-01-01

274

Influence of gravity on cardiac performance.  

PubMed

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. PMID:9846932

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

275

Research outputs in respiratory medicine  

PubMed Central

Background: There is currently little information regarding how much the distribution of research activity in respiratory medicine reflects the interests of its clinicians and scientists, the disease burden in any country, or the availability of funding. Methods: A total of 81 419 respiratory medicine publications identified in the Science Citation Index for the years 1996–2001 were assigned to 14 subject areas (mainly based on title words) and to 15 OECD countries. Outputs were compared with a nation's disease burdens and, for the UK, the sources of research funding were investigated. Results and conclusions: Overall, Finland, Canada, Spain and the UK had the greatest relative commitment to respiratory medicine research expressed as a ratio of their share of world biomedical research. The largest subject areas were asthma, lung cancer, and paediatric lung disease, each with over 1400 papers published per year. Australia and Canada led in relative commitment to sleep research and Sweden and Finland led in research on asthma. Australia and the UK produced significant numbers of publications on cystic fibrosis (CF) but Finland produced few. The Netherlands has a strong output on chronic obstructive pulmonary disease (COPD), France and the UK on diffuse parenchymal lung disease (DPLD), and Finland dominated occupational lung disease research but had few publications on HIV/AIDS where Spain proportionately produced most. Finland and Australia had strong outputs in paediatric lung disease research. For most subject areas the research output of a country correlated poorly with disease burden. In the UK, lung cancer research appeared unduly low in relation to the number of deaths and COPD outputs were low compared with those for asthma. However, correlations were positive for the burden of CF and pulmonary complications of HIV/AIDS which explains, for example, the low outputs in these subject areas from Finland. The strong performance in CF research in the UK is likely to reflect significant charitable funding, while sleep research, pulmonary circulatory disease, and DPLD had little stated external funding or sponsorship. PMID:15618586

Rippon, I; Lewison, G; Partridge, M

2005-01-01

276

NMG documentation, part 3: maintainer`s guide  

SciTech Connect

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.

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

1996-07-01

277

Desktop micro-CT with a nanotube field emission x-ray source for high-resolution cardiac imaging  

NASA Astrophysics Data System (ADS)

We have previously reported the development of a dynamic micro-CT scanner with a stationary mouse bed using a compact carbon nanotube (CNT) field emission x-ray tube and preliminary results on its utility for prospectively gated cardiac imaging. In this paper we report the recent progress in improving the performance characteristics of this scanner. Through optimization of the CNT cathode, the stable emission current has been increased. The output power of the CNT x-ray source has reached ~100W peak power at 100?m focal spot size. The higher flux enables improvement of the xray energy spectrum to minimize the beam hardening effect and increasing the system temporal resolution by using shorter x-ray exposure time. The scanner's temporal resolution has been increased to ~10 msec, which is sufficient for high-resolution micro-CT imaging of mouse heart and lung under free-breathing setting. The spatial resolution is maintained at 6.2 lp per mm at 10% system MTF. The nanotube micro-CT scanner's application in mouse cardiac imaging has been demonstrated with high-resolution (80 ?m and 15 msec) micro-CT of the mouse heart under freebreathing setting.

Cao, Guohua; Calderon-Colon, Xiomara; Burk, Laurel; Lee, Yueh Z.; Sultana, Shabana; Lu, Jianping; Zhou, Otto

2010-04-01

278

A New Frontier for Cardiac Monitoring  

NASA Technical Reports Server (NTRS)

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

2001-01-01

279

Advanced imaging of cardiac sarcoidosis.  

PubMed

Sarcoidosis with cardiac involvement is underdiagnosed and can put patients at risk of morbidity including conduction defects, arrhythmias and heart failure, as well as sudden cardiac death. In addition, cardiac sarcoidosis may have no clinical manifestations or non-specific presentation and diagnosis may be difficult on clinical criteria. Investigation for cardiac sarcoidosis should be considered in those with extra-cardiac sarcoidosis and cardiac findings as well as those under the age of 60 years presenting with atrioventricular block without a clear cause. Advanced imaging modalities including cardiac magnetic resonance and positron emission tomography may help in both the diagnosis and assessment of response to treatment for cardiac sarcoidosis. This ultimately may help to minimize associated adverse outcomes from this enigmatic disease. PMID:25702313

Ayoub, Chadi; Pena, Elena; Ohira, Hiroshi; Dick, Alexander; Leung, Eugene; Nery, Pablo B; Birnie, David; Beanlands, Rob S B

2015-04-01

280

Cardiac contusion: a capricious syndrome.  

PubMed Central

Cardiac contusions are being recognized with frequency. Among 507 patients with non-penetrating chest injuries, 210 had serial electrocardiograms sufficient to evaluate the heart. Forty-five of these 210 patients (21%) had cardiac contusions. These 45 patients and 3 others who were confirmed to have cardiac contusions at necropsy, comprise the 48 patients in this series. Life-indangering cardiac complications occurred in 14 (29%) of the 48 patients, and 4 patients died. The development of cardiac complications following cardiac contusions appears to have a significant relationship to the presence of shock, hypoxia and to factors related to the severity of multiple injuries. These observations have therapeutic implications in management of patients with cardiac contusions through prevention of hypovolemia and hypoxia and avoidance of fluid overload as well as treatment of specific cardiac complications. Images Fig. 4B. Fig. 4C. Fig. 4D. PMID:1130875

Jones, J W; Hewitt, R L; Drapanas, T

1975-01-01

281

Cardiac pacing leads.  

PubMed

Many of the advances that have been seen in the last decade concerning the functionality, size, and longevity of cardiac pacemakers have been dependent upon concomitant advances in cardiac pacing leads. The most difficult component of a pacing lead to develop has been the insulator. There are many choices for physicians implanting pacing leads: active versus passive fixation, standard impedance versus high impedance and polyurethane versus silicone. The current state of affairs of cardiac pacing leads is quite good in that we have leads that have excellent electrical properties and appear to be more resistant to the hostile environment into which the lead is placed. In spite of this, the goal of a perfect lead remains elusive and there continues to be many challenges in lead design. PMID:10709688

Crossley, G H

2000-02-01

282

Cardiac regeneration in children.  

PubMed

Very young mammals have an impressive cardiac regeneration capacity. In contrast, cardiac regeneration is very limited in adult humans. The hearts of young children have a higher regenerative capacity compared with adults, as, for example, seen after surgical correction of an anomalous left coronary artery arising from the pulmonary artery or in children with univentricular hearts, who present enormous morphological changes after volume unloading. In addition, the enormous regenerative potential of growing children's hearts is reflected in the spontaneous courses of children with severely deteriorated cardiac function (e.g., patients with dilated cardiomyopathy). The extent of this regenerative capacity and its time dependency remain to be elucidated in the future and should be exploited to improve the treatment of children with severe heart insufficiency. PMID:25633820

Rupp, Stefan; Schranz, Dietmar

2015-04-01

283

A dual role for integrin-linked kinase and ?1-integrin in modulating cardiac aging  

PubMed Central

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 ?1-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 ?1-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

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

284

Cardiac Tumors: A Brief Commentary  

PubMed Central

Patients with cardiac tumors may present with cardiovascular related or constitutional symptoms, but more often than not a cardiac mass is discovered incidentally during an imaging examination performed for an unrelated indication. Cardiac myxoma is generally considered to be a surgical emergency. Echocardiography, including the transesophageal approach, is the most important means of diagnosis; computed tomography and magnetic resonance imaging. The clinical presentation has changed, and the management of cardiac myxoma now needs to be reviewed. PMID:25538934

Roever, Leonardo; Casella-Filho, Antonio; Dourado, Paulo Magno Martins; Resende, Elmiro Santos; Chagas, Antônio Carlos Palandri

2014-01-01

285

10 CFR 26.71 - Maintaining authorization.  

Code of Federal Regulations, 2012 CFR

...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)...

2012-01-01

286

10 CFR 26.71 - Maintaining authorization.  

Code of Federal Regulations, 2013 CFR

...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)...

2013-01-01

287

Cardiac Bioelectricity and Arrhythmias  

NSDL National Science Digital Library

Deep inside a human heart, its pacemaker sends out bursts of electrical signals that keep the heart pumping rhythmically, supplying life-giving oxygen to the body. When these electrical waves become disorganized, the heart starts beating irregularly or arrhythmically. Flavio Fenton and Elizabeth Cherry of Cornell University made this interactive program to provide education on arrhythmias. It presents detailed information on cardiac anatomy, normal cardiac electrophysiology, and different kinds of arrhythmias using a combination of words, pictures, and interactive, computer simulations and animations.

Flavio Fenton (Cornell University; )

2006-09-22

288

Keeping the engine primed: HIF factors as key regulators of cardiac metabolism and angiogenesis during ischemia.  

PubMed

Myocardial ischemia, the most common cause of cardiac hypoxia in clinical medicine, occurs when oxygen delivery cannot meet myocardial metabolic requirements in the heart. This deficiency can result from either a reduced supply of oxygen (decreased coronary bloodflow) or an increased myocardial demand for oxygen (increased wall stress or afterload). Patients with stable coronary artery disease as well as patients experiencing acute myocardial infarction can experience episodes of severe ischemia. Although hypoxia is an obligatory component, it is not the sole environmental stress experienced by the ischemic heart. Reperfusion after ischemia is associated with increased oxidative stress as the heart reverts to aerobic respiration and thereby generates toxic levels of reactive oxygen species (ROS). During mild ischemia, mitochondrial function is partially compromised and substrate preferences adapt to sustain adequate ATP generation. With severe ischemia, mitochondrial function is markedly compromised and anaerobic metabolism must provide energy no matter what the cost in generation of toxic ROS adducts. Ischemia produces a variety of environmental stresses that impair cardiovascular function. As a result, multiple signaling pathways are activated in mammalian cells during ischemia/reperfusion injury in an attempt to minimize cellular injury and maintain cardiac output. Amongst the transcriptional regulators activated are members of the hypoxia inducible factor (HIF) transcription factor family. HIF factors regulate a variety of genes that affect a myriad of cellular processes including metabolism, angiogenesis, cell survival, and oxygen delivery, all of which are important in the heart. In this review, we will focus on the metabolic and angiogenic aspects of HIF biology as they relate to the heart during ischemia. We will review the metabolic requirements of the heart under normal as well as hypoxic conditions, the effects of preconditioning and its regulation as it pertains to HIF biology, the apparent roles of HIF-1 and HIF-2 in intermediary metabolism, and translational applications of HIF-1 and HIF-2 biology to cardiac angiogenesis. Increased understanding of the role of HIFs in cardiac ischemia will ultimately influence clinical cardiovascular practice. PMID:18026917

Shohet, Ralph V; Garcia, Joseph A

2007-12-01

289

The Outputs of Higher Education.  

ERIC Educational Resources Information Center

Presents a review of efforts over the last several decades to assess the outputs of higher education, including economic and noneconomic, and public and private benefits. Recommends resisting the viewing of higher education merely in terms of its quantifiable economic returns because that line of reasoning diminishes its substantial intangible…

Breneman, David W.

2001-01-01

290

Patient Guide to Cardiac Surgery  

E-print Network

Patient Guide to Cardiac Surgery at the Massachusetts General Hospital #12;Contents Welcome 1 Your cover #12;Welcome to the MGH Cardiac Surgical Service The cardiac surgical team at the Massachusetts General Hospital is committed to giving you the best medical care. As a patient, you are a part of our

Mootha, Vamsi K.

291

Management of the pediatric patient after cardiac surgery.  

PubMed Central

The medical management of the child with congenital cardiac disease prior to and following cardiac surgery has made a substantial contribution to the improved morbidity and mortality attributed to surgical advances. This paper provides a framework for understanding the problems that arise in the perioperative period and a systematic approach, by organ system, to monitoring and management of these problems. The discussion is intended to be of general application, focusing on initial stabilization following surgery and the cardiorespiratory, renal, metabolic, hematologic, and neurologic alterations that result from surgery with cardiopulmonary bypass. An approach for the management of the low output state is also provided. Little attempt has been made to focus on problems unique to a specific type of cardiac disease or certain operative approaches. Rather, it is the contention that an understanding of general principles and an appreciation of the common problems will provide adequate preparation for those responsible for the care of the child. PMID:6375165

Lister, G.

1984-01-01

292

End-tidal CO 2 pressure decreases during exercise in cardiac patients  

Microsoft Academic Search

OBJECTIVESWe measured end-tidal CO2 pressure (PETCO2) during exercise and investigated the relationship between PETCO2 and exercise capacity, ventilatory parameters and cardiac output to determine the mechanism(s) of changes in this parameter.BACKGROUNDIt is unclear whether PETCO2 is abnormal at rest and during exercise in cardiac patients.METHODSCardiac patients (n = 112) and normal individuals (n = 29) performed exercise tests with breath-by-breath

Akihiro Matsumoto; Haruki Itoh; Yoko Eto; Toshio Kobayashi; Makoto Kato; Masao Omata; Hiroshi Watanabe; Kazuzo Kato; Shin-ichi Momomura

2000-01-01

293

Elevated miR499 Levels Blunt the Cardiac Stress Response  

Microsoft Academic Search

BackgroundThe heart responds to myriad stresses by well-described transcriptional responses that involve long-term changes in gene expression as well as more immediate, transient adaptations. MicroRNAs quantitatively regulate mRNAs and thus may affect the cardiac transcriptional output and cardiac function. Here we investigate miR-499, a microRNA embedded within a ventricular-specific myosin heavy chain gene, which is expressed in heart and skeletal

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

2011-01-01

294

Chronic kidney disease is associated with increased risk of sudden cardiac death among patients with coronary artery disease  

Microsoft Academic Search

Sudden cardiac death is the most common cause of mortality among patients with end-stage kidney disease maintained on hemodialysis. To examine whether this increased risk is also seen with less advanced kidney disease, we studied the relationship between glomerular filtration rate and risk of sudden cardiac death in patients with moderate kidney disease and known coronary artery disease. This retrospective

Patrick H Pun; Thomas R Smarz; Emily F Honeycutt; Linda K Shaw; Sana M Al-Khatib; John P Middleton

2009-01-01

295

MK-801, an Excitatory Amino Acid Antagonist, Does Not Improve Neurologic Outcome Following Cardiac Arrest in Cats  

Microsoft Academic Search

Summary: The excitatory amino antagonist MK-801 was administered to cats following resuscitation from cardiac arrest to evaluate its effect on neurologic and neuropathology outcome in a clinically relevant model of complete cerebral ischemia. In 29 cats studied, cardiac arrest (ventricular fibrillation) was maintained for 18 min and resuscitation was successfully performed in 21 cats. Four animals underwent a sham arrest.

Jerry E. Fleischer; Akio Tateishi; John C. Drummond; Mark S. Scheller; Marjorie R. Grafe; Mark H. Zornow; Gary T. Shearman; Harvey M. Shapiro

1989-01-01

296

Nonexercise cardiac stress testing  

SciTech Connect

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

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

1989-09-15

297

Comparative cardiac imaging  

SciTech Connect

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.

Brundage, B.H.

1990-01-01

298

Hepato-cardiac disorders  

PubMed Central

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

Fouad, Yasser Mahrous; Yehia, Reem

2014-01-01

299

Digital cardiac imaging  

SciTech Connect

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

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

1985-01-01

300

Cardiac mitochondria and arrhythmias  

PubMed Central

Despite a high prevalence of sudden cardiac death throughout the world, the mechanisms that lead to ventricular arrhythmias are not fully understood. Over the last 20 years, a growing body of evidence indicates that cardiac mitochondria are involved in the genesis of arrhythmia. In this review, we have attempted to describe the role that mitochondria play in altering the heart's electrical function by introducing heterogeneity into the cardiac action potential. Specifically, we have focused on how the energetic status of the mitochondrial network can alter sarcolemmal potassium fluxes through ATP-sensitive potassium channels, creating a ‘metabolic sink’ for depolarizing wave-fronts and introducing conditions that favour catastrophic arrhythmia. Mechanisms by which mitochondria depolarize under conditions of oxidative stress are characterized, and the contributions of several mitochondrial ion channels to mitochondrial depolarization are presented. The inner membrane anion channel in particular opens upstream of other inner membrane channels during metabolic stress, and may be an effective target to prevent the metabolic oscillations that create action potential lability. Finally, we discuss therapeutic strategies that prevent arrhythmias by preserving mitochondrial membrane potential in the face of oxidative stress, supporting the notion that treatments aimed at cardiac mitochondria have significant potential in attenuating electrical dysfunction in the heart. PMID:20621924

Brown, David A.; O'Rourke, Brian

2010-01-01

301

Ethical Issues in Cardiac Surgery  

PubMed Central

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

Kavarana, Minoo N.; Sade, Robert M.

2012-01-01

302

Biomechanics of Early Cardiac Development  

PubMed Central

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

Goenezen, Sevan; Rennie, Monique Y.

2012-01-01

303

Maternal cardiac metabolism in pregnancy  

PubMed Central

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

Liu, Laura X.; Arany, Zolt

2014-01-01

304

Are Electronic Cardiac Devices Still Evolving?  

PubMed Central

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

Mabo, P.

2014-01-01

305

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

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

306

[Relation between cardiac function and the pulse condition, sphygmogram in patients with hemopathy].  

PubMed

The authors determined the impedance plethysmogram, differentiator (dz/dt), carotid arterial pulse wave, apexcardiogram, electrocardiogram and radial sphygmogram of 106 cases with hemopathy by using a RM-6000 polygraph systems. The results showed that the cardiac function of the patients with hemopathy had obviously been injured. The time of ejecting blood was shortened markedly in the left ventricle. The heart rate increased, total peripheral resistance and cardiac output decreased. These led to the formation of rapid slippery and thready pulse. The formation of string-like pulse is related to the injury of cardiac function and decrease of the arterial compliance. PMID:1504532

Chen, S Y

1992-03-01

307

Standardized multiple output power supply  

NASA Technical Reports Server (NTRS)

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

Ragusa, E. V.

1975-01-01

308

Microgyroscope with closed loop output  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

309

UFO - The Universal FEYNRULES Output  

NASA Astrophysics Data System (ADS)

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.

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

2012-06-01

310

Maintaining consistency in distributed systems  

NASA Technical Reports Server (NTRS)

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.

Birman, Kenneth P.

1991-01-01

311

Output Effects of Government Purchases  

Microsoft Academic Search

The theoretical analysis focuses on the distinction between temporary and permanent movements in government purchases. Under plausible conditions, the temporary case involves an output response that is positive, less than one-to-one with the change in government purchases, and larger than that generated by an equal-sized, but permanent, shift in purchases. The equilibrium real rate of return rises in the temporary

Robert J. Barro

1981-01-01

312

[Cardiac glycosides: From ancient history through Withering's foxglove to endogeneous cardiac glycosides].  

PubMed

For centuries, drugs that increase the power of contraction of the failing heart have been used for the treatment of congestive heart failure (dropsy). The cardiac effect is due to the content of cardiac glycosides. Squill or sea onion, Urginea (Scilla) maritima, a seashore plant, was known by the ancient Romans and Syrians and possibly also by the ancient Egyptians. Squills were used erratically, but some prescriptions indicate that they may have been used for the treatment of oedematous states. The toxic effect of strophanthus species was known from poisoned arrows used by the natives in Africa. Digitalis, derived form the foxglove plant, Digitalis purpurea, is mentioned in writings as early as 1250; a Welsh family, known as the Physicians of Myddvai, collected different herbs and digitalis was included in their prescriptions. However, the druge was used erratically until the 18th century, when William Withering, an English physician and botanist, published a monograph describing the clinical effects of an extract of the foxglove plant. Later, in 1785, the indication and the toxicity of digitalis were reported in his book, "An account of the Foxglove and some of its medical uses with practical remarks on dropsy, and other diseases". In Denmark, the leaves of Digitalis purpurea or Digitalis lanata were tested for cardiac glycoside activity. The standardized digitalis powder was used in tinctures, infusions, and tablets. The preparations were included in successive editions of the Danish pharmacopoeia, some of the tinctures already in 1828, i.e. before the standardization of the drug. Isolation of cardiac glycosides from digitalis, strophanthus and squill and determination of their chemical structures initiated biochemical and pharmacological studies. The scientific advances led to an understanding of cardiac muscle contractility and the Na,K pump as the cellular receptor for the inotropic action of digitalis. Examination of putative endogenous ligands to the receptor revealed some endogenous cardiac glycosides of similar or identical structures as those found in digitalis, strophanthus and squill. Increased concentrations of these glycosides are found in patients with heart failure. Further investigations are needed to determine whether the secretion of glycosides might be a physiologic response to a diminished cardiac output. PMID:15685783

Norn, Svend; Kruse, Poul R

2004-01-01

313

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

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

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

314

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

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.

Huang, Tom H.-W. [Herbal Medicines Research and Education Centre, Faculty of Pharmacy, University of Sydney, NSW 2006 (Australia); Yang Qinglin [Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, GA 30310 (United States); Harada, Masaki [Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Uberai, Jasna [Herbal Medicines Research and Education Centre, Faculty of Pharmacy, University of Sydney, NSW 2006 (Australia); Radford, Jane [Faculty of Medicine, University of Sydney (Australia); Li, George Q. [Herbal Medicines Research and Education Centre, Faculty of Pharmacy, University of Sydney, NSW 2006 (Australia); Yamahara, Johji [Pharmafood Institute, Kyoto (Japan); Roufogalis, Basil D. [Herbal Medicines Research and Education Centre, Faculty of Pharmacy, University of Sydney, NSW 2006 (Australia); Li Yuhao [Herbal Medicines Research and Education Centre, Faculty of Pharmacy, University of Sydney, NSW 2006 (Australia)]. E-mail: yuhao@pharm.usyd.edu.au

2006-01-15

315

Cardiac nuclear medicine  

SciTech Connect

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.

Gerson, M.C.

1987-01-01

316

Primary cardiac lipoblastoma.  

PubMed

Lipoblastoma is a benign adipose tumor in children that has been described in various anatomic locations, most commonly the extremities. We describe the case of a 17-month-old boy diagnosed with cardiac lipoblastoma, a previously unreported primary cardiac tumor in children. Our patient presented with symptoms of coughing, wheezing, and hoarseness and was found to have a large mediastinal mass, which narrowed the left mainstem bronchus and compressed the right atrium and superior vena cava, causing superior vena cava syndrome. Surgical exploration revealed an intrapericardial soft tissue mass arising from the area of the posterior interatrial septum. Grossly, the resected mass was lobulated, pale yellow, and fatty with focal areas of gray myxoid tissue. Microscopically, the tumor consisted of both immature and mature adipocytes, with focal vascular myxoid areas containing lipoblasts, diagnostic of lipoblastoma. Two months after surgery, the patient was in good health without evidence of recurrence. PMID:11370265

Dishop, M K; O'Connor, W N; Abraham, S; Cottrill, C M

2001-01-01

317

Cardiac index and oxygen delivery during low and high tidal volume ventilation strategies in patients with acute respiratory distress syndrome: a crossover randomized clinical trial  

PubMed Central

Introduction The beneficial effect of low tidal volume (TV) ventilation strategy on mortality in patients with acute respiratory distress syndrome (ARDS) has been attributed to the protective effect on ventilator-induced lung injury, and yet its effect on cardiovascular function might also play an important role. The aim of this study was to assess whether low TV ventilation improves cardiac output and oxygen delivery compared with high TV ventilation strategy in patients with ARDS. Methods In this crossover randomized clinical trial 16 ARDS patients were recruited in an intensive care unit at a university-affiliated hospital. Each patient was ventilated for 30 min with low (6 mL/kg) and 30 min with high (12 mL/kg) TV. The two experimental periods, applied in random order and with allocation concealment, were separated by 30 min of basal ventilation. Minute ventilation was constantly maintained by appropriate respiratory rate changes. Results Compared with high TV ventilation, low TV ventilation showed decreased pH (7.37 vs. 7.41, P = 0.001) and increased PaCO2 (49 vs. 43 mmHg; P = 0.002). Cardiac index and oxygen delivery index were increased with low compared with high TV ventilation (3.9 vs. 3.5 L.min-1.m-2, P = 0.012, and 521 vs. 463 mL.min-1.m-2, P = 0.002, respectively), while oxygen extraction ratio decreased (0.36 vs. 0.44, P = 0.027). In four patients oxygen extraction ratio was >0.5 during high TV but not during low TV strategy. The magnitude of the change in cardiac index was positively associated with PaCO2 variation (P = 0.004), while it was unrelated to the magnitude of changes in TV and airway pressure. The decrease of cardiac index was predicted by PaCO2 reduction, with and area under ROC curve of 0.72. Conclusions Our findings suggest that a low TV ventilation strategy increases cardiac index and oxygen delivery, thus supporting the hypothesis that the beneficial effect of low TV ventilation in patients with ARDS could be partially explained by hemodynamic improvement. In other words, low tidal volume ventilation could be protective also for the cardiovascular system and not only for the lung. The slight increase of PaCO2 during low TV ventilation seems to predict the increase of cardiac index. Trial registration ClinicalTrials.gov: NCT00713713 PMID:23880084

2013-01-01

318

Sucrose non-fermenting related kinase enzyme is essential for cardiac metabolism  

PubMed Central

ABSTRACT In this study, we have identified a novel member of the AMPK family, namely Sucrose non-fermenting related kinase (Snrk), that is responsible for maintaining cardiac metabolism in mammals. SNRK is expressed in the heart, and brain, and in cell types such as endothelial cells, smooth muscle cells and cardiomyocytes (CMs). Snrk knockout (KO) mice display enlarged hearts, and die at postnatal day 0. Microarray analysis of embryonic day 17.5 Snrk hearts, and blood profile of neonates display defect in lipid metabolic pathways. SNRK knockdown CMs showed altered phospho-acetyl-coA carboxylase and phospho-AMPK levels similar to global and endothelial conditional KO mouse. Finally, adult cardiac conditional KO mouse displays severe cardiac functional defects and lethality. Our results suggest that Snrk is essential for maintaining cardiac metabolic homeostasis, and shows an autonomous role for SNRK during mammalian development. PMID:25505152

Cossette, Stephanie M.; Gastonguay, Adam J.; Bao, Xiaoping; Lerch-Gaggl, Alexandra; Zhong, Ling; Harmann, Leanne M.; Koceja, Christopher; Miao, Robert Q.; Vakeel, Padmanabhan; Chun, Changzoon; Li, Keguo; Foeckler, Jamie; Bordas, Michelle; Weiler, Hartmut; Strande, Jennifer; Palecek, Sean P.; Ramchandran, Ramani

2015-01-01

319

Sucrose non-fermenting related kinase enzyme is essential for cardiac metabolism.  

PubMed

In this study, we have identified a novel member of the AMPK family, namely Sucrose non-fermenting related kinase (Snrk), that is responsible for maintaining cardiac metabolism in mammals. SNRK is expressed in the heart, and brain, and in cell types such as endothelial cells, smooth muscle cells and cardiomyocytes (CMs). Snrk knockout (KO) mice display enlarged hearts, and die at postnatal day 0. Microarray analysis of embryonic day 17.5 Snrk hearts, and blood profile of neonates display defect in lipid metabolic pathways. SNRK knockdown CMs showed altered phospho-acetyl-coA carboxylase and phospho-AMPK levels similar to global and endothelial conditional KO mouse. Finally, adult cardiac conditional KO mouse displays severe cardiac functional defects and lethality. Our results suggest that Snrk is essential for maintaining cardiac metabolic homeostasis, and shows an autonomous role for SNRK during mammalian development. PMID:25505152

Cossette, Stephanie M; Gastonguay, Adam J; Bao, Xiaoping; Lerch-Gaggl, Alexandra; Zhong, Ling; Harmann, Leanne M; Koceja, Christopher; Miao, Robert Q; Vakeel, Padmanabhan; Chun, Changzoon; Li, Keguo; Foeckler, Jamie; Bordas, Michelle; Weiler, Hartmut; Strande, Jennifer; Palecek, Sean P; Ramchandran, Ramani

2014-01-01

320

Nipping at cardiac remodeling  

PubMed Central

Much of the mortality following myocardial infarction results from remodeling of the heart after the acute ischemic event. Cardiomyocyte apoptosis has been thought to play a key role in this remodeling process. In this issue of the JCI, Diwan and colleagues present evidence that Bnip3, a proapoptotic Bcl2 family protein, mediates cardiac enlargement, reshaping, and dysfunction in mice without influencing infarct size (see the related article beginning on page 2825). PMID:17909620

Whelan, Russell S.; Mani, Kartik; Kitsis, Richard N.

2007-01-01

321

Cardiac stem cell therapy  

Microsoft Academic Search

In cardiac stem cell therapy, the past decade has been interesting with respect to preclinical and clinical research. The\\u000a high diversity of applied stem cell populations and evaluation methods represent a challenge to fully understand the impact\\u000a of stem cell administration, leaving uncertain answers to the questions that have been dealt with thus far. In the present\\u000a work, registered studies

C. Nesselmann; A. Kaminski; G. Steinhoff

2011-01-01

322

Blunt cardiac injury.  

PubMed

In summary, the incidence of BCI following blunt thoracic trauma patients has been reported between 20% and 76%, and no gold standard exists to diagnose BCI. Diagnostic tests should be limited to identify those patients who are at risk of developing cardiac complications as a result of BCI. Therapeutic interventions should be directed to treat the complications of BCI. Finally, the prognosis and outcome of BCI patients is encouraging PMID:14979329

Schultz, Jess M; Trunkey, Donald D

2004-01-01

323

Understanding Cardiac Calcium Channelopathies  

Microsoft Academic Search

imothy syndrome is a rare genetic disorder characterized by QT prolongation (designated LQT8), arrhythmias and sudden death, structural heart disease, cognitive defects with autism, syndactyly (webbed fingers and toes), hypoglycemia, and immune deficiencies.1,2 A single mutation (G406R) in exon 8a of the cardiac L-type calcium channel (CACNA1C, Cav1.2, 1c) was shown to cause Timothy syndrome in multiple unrelated subjects, whereas

Barry London

324

Engineered Human Cardiac Tissue  

Microsoft Academic Search

The human heart is the first organ to develop during embryogenesis and is arguably the most essential organ for life. However,\\u000a after birth, the heart has very little capacity to repair malformations such as congenital heart defects or to regenerate\\u000a after an injury such as myocardial infarction. Cardiac tissue engineering addresses the need for a therapeutic biologic implant\\u000a to restore

Kareen L. Kreutziger; Charles E. Murry

2011-01-01

325

Cardiac rehabilitation I  

Microsoft Academic Search

Cardiovascular disease (CVD) is the leading cause of death and disability for women and men. There are gender differences in recovery from coronary events, which may be due physiological, sociodemographic, or psychosocial factors. Cardiac rehabilitation programs have beneficial effects on coronary recovery. The following presents a review of the literature from MedLine (1997–2001) and PsychInfo (1984–2001) on gender differences in

Sherry L. Grace; Susan E. Abbey; Zachary M. Shnek; Jane Irvine; Renée-Louise Franche; Donna E. Stewart

2002-01-01

326

Cardiac arrhythmias during sleep  

Microsoft Academic Search

Summary  Different types of cardiac arrhythmias may arise in healthy subjects during sleep. Whereas bradyarrhythmias (severe sinus\\u000a bradycardia, sinus arrest, first and second degree A-V blocks) predominate in the young, elderly subjects more commonly present\\u000a supraventricular and ventricular ectopic beats and tachyarrhythmias (supraventricular paroxysmal tachycardia, atrial flutter,\\u000a etc.). A rare potentially life-threatening syndrome, characterised by sinus arrests accompanied by vagal overactivity,

Giorgio Coccagna

2000-01-01

327

Tissue-engineered cardiac constructs for cardiac repair.  

PubMed

Several recent basic research studies have described surgical methods for cardiac repair using tissue cardiomyoplasty. This review summarizes recent advances in cardiac repair using bioengineered tissue from the viewpoint of the cardiac surgeon. We conclude that the results of many basic and preclinical studies indicate that bioengineered tissue can be adapted to conventional surgical techniques. However, no clinical studies have yet proved bioengineered tissue is effective as a treatment for human heart failure. Today's cardiac surgeons can look forward to the advent of new techniques to benefit patients who respond poorly to existing treatment for heart failure. PMID:21172551

Miyagawa, Shigeru; Roth, Matthias; Saito, Atsuhiro; Sawa, Yoshiki; Kostin, Sawa

2011-01-01

328

The Alberta Cardiac Access Collaborative: improving the cardiac patient journey.  

PubMed

The Alberta Cardiac Access Collaborative (ACAC) is a joint initiative of Alberta's health system to improve access to adult cardiac services across the patient journey. ACAC has created new care delivery models and implemented best practices across Alberta in four streams across the continuum: heart attack, patient navigation, heart failure and arrhythmia. Emergency medical providers, nurses, primary care physicians, hospitals, cardiac specialists and clinicians are all working together to integrate services, bridge jurisdictions and geography with one aim--improving the patient journey for adults in need of cardiac care. PMID:20057256

Blackadar, Robyn; Houle, Mishaela

2009-01-01

329

Neuregulin-1 attenuated doxorubicin-induced decrease in cardiac troponins  

PubMed Central

Neuregulin-1 (NRG1) is a potential therapeutic agent for the treatment of doxorubicin (Dox)-induced heart failure. NRG1, however, activates the erbB2 receptor, which is frequently overexpressed in breast cancers. It is, therefore, important to understand how NRG1, via erbB2, protects the heart against Dox cardiotoxicity. Here, we studied NRG1-erbB2 signaling in Dox-treated mice hearts and in isolated neonatal rat ventricular myocytes (NRVM). Male C57BL/6 mice were treated with recombinant NRG1 before and daily after a single dose of Dox. Cardiac function was determined by catheterization. Two-week survival was analyzed by the Kaplan-Meier method. Cardiac troponins [cardiac troponin I (cTnI) and cardiac troponin T (cTnT)] and phosphorylated Akt protein levels were determined in mice hearts and in NRVM by Western blot analysis. Activation of caspases and ubiquitinylation of troponins were determined in NRVM by caspase assay and immunoprecipitation. NRG1 significantly improved survival and cardiac function in Dox-treated mice. NRG1 reduced the decrease in cTnI, cTnT, and cardiac troponin C (cTnC) and maintained Akt phosphorylation in Dox-treated mice hearts. NRG1 reduced the decrease in cTnI and cTnT mRNA and proteins in Dox-treated NRVM. Inhibition of erbB2, phosphoinositide 3-kinase (PI3K), Akt, and mTOR blocked the protective effects of NRG1 on cTnI and cTnT in NRVM. NRG1 significantly reduced Dox-induced caspase activation, which degraded troponins, in NRVM. NRG1 reduced Dox-induced proteasome degradation of cTnI. NRG1 attenuates Dox-induced decrease in cardiac troponins by increasing transcription and translation and by inhibiting caspase activation and proteasome degradation of troponin proteins. NRG1 maintains cardiac troponins by the erbB2-PI3K pathway, which may lessen Dox-induced cardiac dysfunction. PMID:19801490

Bian, Yun; Sun, Maoyun; Silver, Marcy; Ho, Kalon K. L.; Marchionni, Mark A.; Caggiano, Anthony O.; Stone, James R.; Amende, Ivo; Hampton, Thomas G.; Morgan, James P.

2009-01-01

330

Cardiac hybrid imaging.  

PubMed

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

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

2014-05-01

331

Cardiac outflow tract anomalies  

PubMed Central

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

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

2014-01-01

332

Nuclear imaging for cardiac amyloidosis.  

PubMed

Histological analysis of endomyocardial tissue is still the gold standard for the diagnosis of cardiac amyloidosis, but has its limitations. Accordingly, there is a need for non-invasive modalities to diagnose cardiac amyloidosis. Echocardiography and ultrasound and magnetic resonance imaging can show characteristics which may not be very specific for cardiac amyloid. Nuclear medicine has gained a precise role in this context: several imaging modalities have become available for the diagnosis and prognostic stratification of cardiac amyloidosis during the last two decades. The different classes of radiopharmaceuticals have the potential to bind different constituents of the amyloidotic infiltrates, with some relevant differences among the various aetiologic types of amyloidosis and the different organs and tissues involved. This review focuses on the background of the commonly used modalities, their present clinical applications, and future clinical perspectives in imaging patients with (suspected) cardiac amyloidosis. The main focus is on conventional nuclear medicine (bone scintigraphy, cardiac sympathetic innervation) and positron emission tomography. PMID:25424887

Noordzij, Walter; Glaudemans, Andor W J M; Longhi, Simone; Slart, Riemer H J A; Lorenzini, Massimiliano; Hazenberg, Bouke P C; Rapezzi, Claudio

2015-03-01

333

Cardiac Emergencies in Neurosurgical Patients  

PubMed Central

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

Petropolis, Andrea; Cappellani, Ronald B.

2015-01-01

334

An overview of cardiac morphogenesis.  

PubMed

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

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

2013-11-01

335

Effects of Ozone and Particulate Matter on Cardiac Mechanics: Role of the Atrial Natriuretic Peptide Gene  

PubMed Central

A positive association between air pollution exposure and increased human risk of chronic heart disease progression is well established. In the current study, we test two hypotheses: (1) the cardiac compensatory changes in response to air pollution are dependent on its composition and (2) specific cardiac adaptations are regulated by atrial natriuretic peptide (ANP). We address these hypotheses by initially examining the exposure effects of ozone (O3) and/or particulate matter (PM) on cardiac function in C57Bl/6J (B6) mice. Subsequently, the results are compared with cardiac functional changes to the same exposures in Nppa (the precursor gene for ANP) knockout (KO) mice. Separate groups of mice underwent 3 consecutive days of the same exposure sequence for 3h each consisting of the following: (1) 6h of filtered air (FAFA), (2) O3 then FA (O3FA), (3) FA then carbon black (FACB), or (4) O3 then CB. Cardiac function was assessed using a conductance catheter to generate cardiac pressure-volume loops 8–10h following each exposure sequence. As compared with FAFA, each sequence led to a substantial drop (as much as 33%) in stroke volume and cardiac output. However, these losses of cardiac function occurred by different compensatory mechanisms dependent on the pollutant composition. For example, O3FA exposure led to reductions in both end-systolic and end-diastolic left ventricular (LV) volumes, whereas FACB exposure led an increase in end-diastolic LV volume. These same cardiac compensatory changes were largely abolished in Nppa KO mice following O3FA or FACB exposure. These results suggest that cardiac functional changes in response to air pollution exposure are strongly dependent on the pollutant constituents, especially related to O3 and/or PM. Furthermore, ANP regulation appears to be crucial to these cardiac compensatory mechanisms induced by air pollution. PMID:22977167

Tankersley, Clarke G.

2013-01-01

336

Sudden cardiac death – Historical perspectives  

PubMed Central

Sudden cardiac death (SCD) is an unexpected death due to cardiac causes that occurs in a short time period (generally within 1 h of symptom onset) in a person with known or unknown cardiac disease. It is believed to be involved in nearly a quarter of human deaths, with ventricular fibrillation being the most common mechanism. It is estimated that more than 7 million lives per year are lost to SCD worldwide. Historical perspectives of SCD are analyzed with a brief description on how the developments in the management of sudden cardiac arrest evolved over time. PMID:24568828

Abhilash, S.P.; Namboodiri, Narayanan

2014-01-01

337

CT Imaging: Cardiac Electrophysiology Applications  

Microsoft Academic Search

\\u000a An understanding of detailed 3-D cardiac anatomy is important to the field of cardiac electrophysiology. Cardiovascular computed\\u000a tomographic angiography (CCTA) can comprehensively assess cardiovascular structure and function relevant to the assessment,\\u000a treatment, and follow-up of patients with electrophysiologically-related disease processes. CCTA provides 3-D visualization\\u000a of cardiac chambers, coronary vessels, and thoracic vasculature including structures particularly important to cardiac electrophysiology,\\u000a such

Jerold S. Shinbane; Marc J. Girsky; Leslie A. Saxon; Michael K. Cao; David A. Cesario; Matthew J. Budoff

338

Cardiac Dysautonomia in Huntington's Disease.  

PubMed

Huntington's disease is a fatal, hereditary, neurodegenerative disorder best known for its clinical triad of progressive motor impairment, cognitive deficits and psychiatric disturbances. Although a disease of the central nervous system, mortality surveys indicate that heart disease is a leading cause of death. The nature of such cardiac abnormalities remains unknown. Clinical findings indicate a high prevalence of autonomic nervous system dysfunction - dysautonomia - which may be a result of pathology of the central autonomic network. Dysautonomia can have profound effects on cardiac health, and pronounced autonomic dysfunction can be associated with neurogenic arrhythmias and sudden cardiac death. Significant advances in the knowledge of neural mechanisms in cardiac disease have recently been made which further aid our understanding of cardiac mortality in Huntington's disease. Even so, despite the evidence of aberrant autonomic activity the potential cardiac consequences of autonomic dysfunction have been somewhat ignored. In fact, underlying cardiac abnormalities such as arrhythmias have been part of the exclusion criteria in clinical autonomic Huntington's disease research. A comprehensive analysis of cardiac function in Huntington's disease patients is warranted. Further experimental and clinical studies are needed to clarify how the autonomic nervous system is controlled and regulated in higher, central areas of the brain - and how these regions may be altered in neurological pathology, such as Huntington's disease. Ultimately, research will hopefully result in an improvement of management with the aim of preventing early death in Huntington's disease from cardiac causes. PMID:25062674

Abildtrup, Mads; Shattock, Michael

2013-01-01

339

Hierarchical approaches for systems modeling in cardiac development.  

PubMed

Ordered cardiac morphogenesis and function are essential for all vertebrate life. The heart begins as a simple contractile tube, but quickly grows and morphs into a multichambered pumping organ complete with valves, while maintaining regulation of blood flow and nutrient distribution. Though not identical, cardiac morphogenesis shares many molecular and morphological processes across vertebrate species. Quantitative data across multiple time and length scales have been gathered through decades of reductionist single variable analyses. These range from detailed molecular signaling pathways at the cellular levels to cardiac function at the tissue/organ levels. However, none of these components act in true isolation from others, and each, in turn, exhibits short- and long-range effects in both time and space. With the absence of a gene, entire signaling cascades and genetic profiles may be shifted, resulting in complex feedback mechanisms. Also taking into account local microenvironmental changes throughout development, it is apparent that a systems level approach is an essential resource to accelerate information generation concerning the functional relationships across multiple length scales (molecular data vs physiological function) and structural development. In this review, we discuss relevant in vivo and in vitro experimental approaches, compare different computational frameworks for systems modeling, and the latest information about systems modeling of cardiac development. Finally, we conclude with some important future directions for cardiac systems modeling. PMID:23463736

Gould, Russell A; Aboulmouna, Lina M; Varner, Jeffrey D; Butcher, Jonathan T

2013-01-01

340

Amino Acids as Metabolic Substrates during Cardiac Ischemia  

PubMed Central

The heart is well known as a metabolic omnivore in that it is capable of consuming fatty acids, glucose, ketone bodies, pyruvate, lactate, amino acids and even its own constituent proteins, in order of decreasing preference. The energy from these substrates supports not only mechanical contraction, but also the various transmembrane pumps and transporters required for ionic homeostasis, electrical activity, metabolism and catabolism. Cardiac ischemia – for example, due to compromise of the coronary vasculature or end-stage heart failure – will alter both electrical and metabolic activity. While the effects of myocardial ischemia on electrical propagation and stability have been studied in depth, the effects of ischemia on metabolic substrate preference has not been fully appreciated: oxygen deprivation during ischemia will significantly alter the relative ability of the heart to utilize each of these substrates. Although changes in cardiac metabolism are understood to be an underlying component in almost all cardiac myopathies, the potential contribution of amino acids in maintaining cardiac electrical conductance and stability during ischemia is underappreciated. Despite clear evidence that amino acids exert cardioprotective effects in ischemia and other cardiac disorders, their role in the metabolism of the ischemic heart has yet to be fully elucidated. This review synthesizes the current literature of the metabolic contribution of amino acids during ischemia by analyzing relevant historical and recent research. PMID:23354395

Drake, Kenneth J.; Sidorov, Veniamin Y.; McGuinness, Owen P.; Wasserman, David H.; Wikswo, John P.

2013-01-01

341

Amino acids as metabolic substrates during cardiac ischemia.  

PubMed

The heart is well known as a metabolic omnivore in that it is capable of consuming fatty acids, glucose, ketone bodies, pyruvate, lactate, amino acids and even its own constituent proteins, in order of decreasing preference. The energy from these substrates supports not only mechanical contraction, but also the various transmembrane pumps and transporters required for ionic homeostasis, electrical activity, metabolism and catabolism. Cardiac ischemia - for example, due to compromise of the coronary vasculature or end-stage heart failure - will alter both electrical and metabolic activity. While the effects of myocardial ischemia on electrical propagation and stability have been studied in depth, the effects of ischemia on metabolic substrate preference has not been fully appreciated: oxygen deprivation during ischemia will significantly alter the relative ability of the heart to utilize each of these substrates. Although changes in cardiac metabolism are understood to be an underlying component in almost all cardiac myopathies, the potential contribution of amino acids in maintaining cardiac electrical conductance and stability during ischemia is underappreciated. Despite clear evidence that amino acids exert cardioprotective effects in ischemia and other cardiac disorders, their role in the metabolism of the ischemic heart has yet to be fully elucidated. This review synthesizes the current literature of the metabolic contribution of amino acids during ischemia by analyzing relevant historical and recent research. PMID:23354395

Drake, Kenneth J; Sidorov, Veniamin Y; McGuinness, Owen P; Wasserman, David H; Wikswo, John P

2012-12-01

342

Dual roles of telomerase in cardiac protection and repair.  

PubMed

Together, the limited capacity for regenerative growth in cardiac muscle after injury and the prevalence of ongoing sporadic cell death due to apoptosis in chronic heart failure states pose one of the paramount challenges in heart failure therapeutics. In adults, the unique self-renewal potential of progenitor/stem cells is associated with telomerase reverse transcriptase (TERT), an RNA-dependent DNA polymerase that maintains the lariat-like loop capping chromosome ends. We have identified telomere uncapping, mediated by down-regulation of telomere repeat-binding factor 2 (TRF2) as a novel trigger of cell death in human dilated cardiomyopathy. Conversely, we identified a residual TERT+ population in adult myocardium, as a potential source of cardiac progenitor cells. Residual TERT expression was localized to cells expressing stem cell antigen 1 (Sca1). Cardiac-resident Sca1+ cells lack haematopoietic stem cell markers and transcripts for cardiac structural genes, yet express many cardiogenic transcription factors. If given intravenously to mice just after ischemia-reperfusion injury, cardiac Sca1+ cells home selectively to injured myocardium and differentiate spontaneously in situ. PMID:17019817

Schneider, Michael D

2006-01-01

343

7 CFR 1430.508 - Maintaining records.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Maintaining records. 1430.508 Section 1430.508 Agriculture Regulations of the Department...PRODUCTS Dairy Market Loss Assistance Program § 1430.508 Maintaining records. Dairy operations...

2010-01-01

344

7 CFR 1430.312 - Maintaining records.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Maintaining records. 1430.312 Section 1430.312 Agriculture Regulations of the Department... 2004 Dairy Disaster Assistance Payment Program § 1430.312 Maintaining records. Persons applying...

2010-01-01

345

7 CFR 1430.612 - Maintaining records.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Maintaining records. 1430.612 Section 1430.612 Agriculture Regulations of the Department...Disaster Assistance Payment Program II (DDAP-II) § 1430.612 Maintaining records. Persons applying...

2010-01-01

346

What to Expect during Cardiac Rehabilitation  

MedlinePLUS

... NHLBI on Twitter. What To Expect During Cardiac Rehabilitation During cardiac rehabilitation (rehab), you'll learn how to: Increase your ... Rate This Content: Next >> December 24, 2013 Cardiac Rehabilitation Clinical Trials Clinical trials are research studies that ...

347

Red wine antioxidant resveratrol-modified cardiac stem cells regenerate infarcted myocardium  

PubMed Central

Abstract To study the efficiency of maintaining the reduced tissue environment via pre-treatment with natural antioxidant resveratrol in stem cell therapy, we pre-treated male Sprague-Dawley rats with resveratrol (2.5 mg/kg/day gavaged for 2 weeks). After occlusion of the left anterior descending coronary artery (LAD), adult cardiac stem cells stably expressing EGFP were injected into the border zone of the myocardium. One week after the LAD occlusion, the cardiac reduced environment was confirmed in resveratrol-treated rat hearts by the enhanced expression of nuclear factor-E2-related factor-2 (Nrf2) and redox effector factor-1 (Ref-1). In concert, cardiac functional parameters (left ventricular ejection fraction and fractional shortening) were significantly improved. The improvement of cardiac function was accompanied by the enhanced stem cell survival and proliferation as demonstrated by the expression of cell proliferation marker Ki67 and differentiation of stem cells towards the regeneration of the myocardium as demonstrated by the enhanced expression of EGFP 28 days after LAD occlusion in the resveratrol-treated hearts. Our results demonstrate that resveratrol maintained a reduced tissue environment by overexpressing Nrf2 and Ref-1 in rats resulting in an enhancement of the cardiac regeneration of the adult cardiac stem cells as demonstrated by increased cell survival and differentiation leading to cardiac function. PMID:20716127

Gurusamy, Narasimman; Ray, Diptarka; Lekli, Istvan; Das, Dipak K

2010-01-01

348

AMPK Regulation of Cardiac Metabolism in Heart Disease  

Microsoft Academic Search

AMP-activated protein kinase (AMPK) plays an important role in regulating cardiac metabolism, and once stimulated, AMPK turns\\u000a on ATP-generating mechanisms believed to be essential in maintaining a normal heart function. AMPK is activated during various\\u000a physiological or pathophysiological conditions. During cellular stresses, such as glucose deprivation, ischemia, hypoxia,\\u000a and oxidative stress, ATP generation is compromised, leading to a rise in

Ding An; Min-Suk Kim; Brian Rodrigues

349

The Network Structure of Economic Output  

E-print Network

Much of the analysis of economic growth has focused on the study of aggregate output. Here, we deviate from this tradition and look instead at the structure of output embodied in the network connecting countries to the ...

Hidalgo, Cesar A.

350

Maintaining Minimum Spanning Trees in Dynamic Graphs  

E-print Network

Maintaining Minimum Spanning Trees in Dynamic Graphs Monika R. Henzinger 1 and Valerie King 2 1 for maintaining a minimum spanning tree in time o( p n) per operation. To be precise, the algorithm uses O(n 1 We consider the problem of maintaining a minimum spanning tree during an arbitrary sequence of edge

King, Valerie

351

Initial efficacy of a cardiac rehabilitation transition program: Cardiac TRUST.  

PubMed

The purpose of this pilot study was to test the initial efficacy, feasibility, and safety of a specially designed postacute care transitional rehabilitation intervention for cardiac patients. Cardiac Transitional Rehabilitation Using Self-Management Techniques (Cardiac TRUST) is a family-focused intervention that includes progressive low-intensity walking and education in self-management skills to facilitate recovery following a cardiac event. Using a randomized two-group design, exercise self-efficacy, steps walked, and participation in an outpatient cardiac rehabilitation (CR) program were compared in a sample of 38 older adults (17 Cardiac TRUST, 21 usual care). At discharge from postacute care, the intervention group trended toward higher levels of self-efficacy for exercise outcomes than the usual care group. During the 6 weeks following discharge, the intervention group had greater attendance in outpatient CR and a trend toward more steps walked during the first week. The feasibility of the intervention was better for the home health care participants than for those in the skilled nursing facility. The provision of CR during postacute care has the potential to bridge the gap in transitional services from hospitalization to outpatient CR for these patients at high risk for future cardiac events. Further evidence of the efficacy of Cardiac TRUST is warranted. PMID:22084960

Dolansky, Mary A; Zullo, Melissa D; Boxer, Rebecca S; Moore, Shirley M

2011-12-01

352

Optimal output-transitions for linear systems  

Microsoft Academic Search

This article addresses the optimal (minimum-input-energy) output-transition problem for linear systems. The goal is to transfer the output from an initial value y(t )= y (for all time t 6 ti) to a \\/nal output value y(t )= 0 y (for all time t ¿ tf ). Previous methods solve this output-transition problem by transforming it into a state-transition problem;

Hector Perez; Santosh Devasia

2003-01-01

353

Command system output bit verification  

NASA Technical Reports Server (NTRS)

An automatic test was developed to test the ability of the deep space station (DSS) command subsystem and exciter to generate and radiate, from the exciter, the correct idle bit sequence for a given flight project or to store and radiate received command data elements and files without alteration. This test, called the command system output bit verification test, is an extension of the command system performance test (SPT) and can be selected as an SPT option. The test compares the bit stream radiated from the DSS exciter with reference sequences generated by the SPT software program. The command subsystem and exciter are verified when the bit stream and reference sequences are identical. It is a key element of the acceptance testing conducted on the command processor assembly (CPA) operational program (DMC-0584-OP-G) prior to its transfer from development to operations.

Odd, C. W.; Abbate, S. F.

1981-01-01

354

Digital plus analog output encoder  

NASA Technical Reports Server (NTRS)

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

Hafle, R. S. (inventor)

1976-01-01

355

Low temperature cardiac response to exhaustive exercise in fish with different levels of winter quiescence.  

PubMed

We examined the cardiac responses of different fish species to anaerobic exercise at low temperatures (3 degrees C). Three species of sympatric warmwater fish with perceived differences in winter activity were used for this comparative study: the winter-quiescent largemouth bass (Micropterus salmoides); the winter-active white bass (Morone chrysops); and the intermediately winter-active black crappie (Pomoxis nigromaculatus). Perceived differences in winter activity were reflected in cardiac responses; e.g. basal cardiac values were lowest for largemouth bass, highest for white bass, and intermediate for black crappie. In addition, cardiac recovery was most rapid for white bass, slowest for largemouth bass and intermediate for black crappie. When disturbed at low temperatures, largemouth bass and black crappie elevated cardiac output principally through increases in heart rate despite substantial decreases in stroke volume. Conversely, white bass principally used stroke volume modulation to change cardiac output. The results of this study indicate that different species respond differently to exercise at low temperatures. Management strategies should recognize that such variation exists and ensure that management decisions are based upon an understanding of the low temperature exercise physiology and winter biology of the species of interest. PMID:12507619

Cooke, Steven J; Grant, Emily C; Schreer, Jason F; Philipp, David P; Devries, Arthur L

2003-01-01

356

Basal ganglia outputs map instantaneous position coordinates during behavior.  

PubMed

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

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

2015-02-11

357

Light-operated proximity detector with linear output  

DOEpatents

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.

Simpson, Marc L. (Harriman, TN); McNeilly, David R. (Maryville, TN)

1985-01-01

358

Light-operated proximity detector with linear output  

DOEpatents

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.

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

1984-01-01

359

Dielectric elastomer transducers with enhanced force output and work density  

NASA Astrophysics Data System (ADS)

We demonstrate that the force output and work density of polydimethylsiloxane (PDMS) based dielectric elastomer transducers can be significantly enhanced by the addition of high permittivity titanium dioxide nanoparticles. The nanocomposites are capable of maintaining the actuation strain performance of the pure PDMS at relatively low electric fields while increasing the force output and work density due to mechanical reinforcement. A model relating the Maxwell stress to the measured force from the actuator was used to determine the dielectric permittivity at high electric fields thus providing results that can be directly correlated to device performance. This approach toward higher work density materials should enable smaller, lighter, and less intrusive actuator systems ideal for biomedical and robotic devices in particular.

Stoyanov, Hristiyan; Brochu, Paul; Niu, Xiaofan; Della Gaspera, Enrico; Pei, Qibing

2012-06-01

360

Effect of hypokinesia on cardiac contractile function and nervous regulation of the heart  

NASA Technical Reports Server (NTRS)

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.

Meyerson, F. Z.; Kapelko, V. I.; Gorina, M. S.; Shchegolkov, A. N.; Larinov, N. P.

1980-01-01

361

Health Instruction Packages: Cardiac Anatomy.  

ERIC Educational Resources Information Center

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…

Phillips, Gwen; And Others

362

Optogenetic Control of Cardiac Function  

Microsoft Academic Search

The cardiac pacemaker controls the rhythmicity of heart contractions and can be substituted by a battery-operated device as a last resort. We created a genetically encoded, optically controlled pacemaker by expressing halorhodopsin and channelrhodopsin in zebrafish cardiomyocytes. Using patterned illumination in a selective plane illumination microscope, we located the pacemaker and simulated tachycardia, bradycardia, atrioventricular blocks, and cardiac arrest. The

Aristides B. Arrenberg; Didier Y. R. Stainier; Herwig Baier; Jan Huisken

2010-01-01

363

Evolutionary innovations in cardiac pacing  

Microsoft Academic Search

Cardiac pacing has played a significant role in mitigating morbidity and mortality associated with bradyarrhythmias. Throughout the years, advances made in battery reliability, lead performance, and device portability have rapidly expanded the use of cardiac pacemakers in many different disease states. Despite the benefits, there has been growing awareness of the potential deleterious effects of long-term artificial electrical stimulation including

Alan Cheng; Larisa G. Tereshchenko

364

Current perspectives on cardiac amyloidosis  

PubMed Central

Amyloidosis represents a group of diseases in which proteins undergo misfolding to form insoluble fibrils with subsequent tissue deposition. While almost all deposited amyloid fibers share a common nonbranched morphology, the affected end organs, clinical presentation, treatment strategies, and prognosis vary greatly among this group of diseases and are largely dependent on the specific amyloid precursor protein. To date, at least 27 precursor proteins have been identified to result in either local tissue or systemic amyloidosis, with nine of them manifesting in cardiac deposition and resulting in a syndrome termed “cardiac amyloidosis” or “amyloid cardiomyopathy.” Although cardiac amyloidosis has been traditionally considered to be a rare disorder, as clinical appreciation and understanding continues to grow, so too has the prevalence, suggesting that this disease may be greatly underdiagnosed. The most common form of cardiac amyloidosis is associated with circulating amyloidogenic monoclonal immunoglobulin light chain proteins. Other major cardiac amyloidoses result from a misfolding of products of mutated or wild-type transthyretin protein. While the various cardiac amyloidoses share a common functional consequence, namely, an infiltrative cardiomyopathy with restrictive pathophysiology leading to progressive heart failure, the underlying pathophysiology and clinical syndrome varies with each precursor protein. Herein, we aim to provide an up-to-date overview of cardiac amyloidosis from nomenclature to molecular mechanisms and treatment options, with a particular focus on amyloidogenic immunoglobulin light chain protein cardiac amyloidosis. PMID:22058156

Guan, Jian; Mishra, Shikha; Falk, Rodney H.

2012-01-01

365

Challenges in Cardiac Tissue Engineering  

PubMed Central

Cardiac tissue engineering aims to create functional tissue constructs that can reestablish the structure and function of injured myocardium. Engineered constructs can also serve as high-fidelity models for studies of cardiac development and disease. In a general case, the biological potential of the cell—the actual “tissue engineer”—is mobilized by providing highly controllable three-dimensional environments that can mediate cell differentiation and functional assembly. For cardiac regeneration, some of the key requirements that need to be met are the selection of a human cell source, establishment of cardiac tissue matrix, electromechanical cell coupling, robust and stable contractile function, and functional vascularization. We review here the potential and challenges of cardiac tissue engineering for developing therapies that could prevent or reverse heart failure. PMID:19698068

Tandon, Nina; Godier, Amandine; Maidhof, Robert; Marsano, Anna; Martens, Timothy P.; Radisic, Milica

2010-01-01

366

Cardiac Remodeling in Obesity  

PubMed Central

The dramatic increase in the prevalence of obesity and its strong association with cardiovascular disease have resulted in unprecedented interest in understanding the effects of obesity on the cardiovascular system. A consistent, but puzzling clinical observation is that obesity confers an increased susceptibility to the development of cardiac disease, while at the same time affording protection against subsequent mortality (termed the obesity paradox). In this review we focus on evidence available from human and animal model studies and summarize the ways in which obesity can influence structure and function of the heart. We also review current hypotheses regarding mechanisms linking obesity and various aspects of cardiac remodeling. There is currently great interest in the role of adipokines, factors secreted from adipose tissue, and their role in the numerous cardiovascular complications of obesity. Here we focus on the role of leptin and the emerging promise of adiponectin as a cardioprotective agent. The challenge of understanding the association between obesity and heart failure is complicated by the multifaceted interplay between various hemodynamic, metabolic, and other physiological factors that ultimately impact the myocardium. Furthermore, the end result of obesity-associated changes in the myocardial structure and function may vary at distinct stages in the progression of remodeling, may depend on the individual pathophysiology of heart failure, and may even remain undetected for decades before clinical manifestation. Here we summarize our current knowledge of this complex yet intriguing topic. PMID:18391168

ABEL, E. DALE; LITWIN, SHELDON E.; SWEENEY, GARY

2010-01-01

367

Safer cardiac surgery.  

PubMed

Safety in cardiac surgery should be evaluated in the context of the other elements of quality in healthcare (timeliness, effectiveness, efficiency, equity, and most importantly, patient-centeredness). Mortality alone is not an adequate index of safety: Stroke is particularly feared by patients and prolonged periods of hospitalization can be very difficult for families to cope with. Advances in knowledge, technology, and medications have improved outcomes, but pharmacological means of reducing cerebral dysfunction after cardiopulmonary bypass remain elusive. Clear differences can be demonstrated between the results of different surgeons and also between different anesthesiologists. The World Health Organization's recently introduced Surgical Safety Checklist provides a validated and inexpensive cognitive aid to reduce human error and improve teamwork and communication in the operating room. Patient selection is very important, and patients should be given clear information on the relative merits of alternative treatments (for example, coronary surgery, percutaneous intervention, and medical treatment in the case of coronary artery disease). In the end, outcomes that the patients themselves desire are the most meaningful endpoint of the pursuit of safer cardiac surgery. PMID:20092087

Merry, Alan F

2009-12-01

368

Concrete induced cardiac contusion.  

PubMed

A previously fit 22 year old man was struck in the chest by a concrete block dropped through the windscreen of his car while he was driving on the motorway. He suffered extensive chest wall trauma and lung contusion, which subsequently precipitated acute respiratory distress. On admission ECG showed right bundle branch block and left axis deviation. Three days later QRS duration was normal but there was anterior ST segment elevation and subsequent T wave change. There was a large rise in creatine kinase, and echocardiography revealed septal and apical hyokinesis as well as a mobile mass attached to the left side of the interventricular septum, which had the echogenic texture of myocardium. The patient had fixed perfusion defects in the areas of hypokinesis on thallium scanning but the coronary arteries were unobstructed at angiography. He was treated with warfarin in the short term and an angiotensin converting enzyme inhibitor in the longer term and has made an asymptomatic recovery. Outpatient echocardiography two months after the injury demonstrated some recovery in overall left ventricular systolic function and no evidence of the intracardiac mass. This case illustrates some of the typical features of non-fatal cardiac contusion associated with non-penetrating cardiac trauma, and was complicated by partial thickness avulsion of a strip of the myocardium in the interventricular septum. PMID:9391297

Curzen, N; Brett, S; Fox, K

1997-09-01

369

Decoding the Cardiac Message  

PubMed Central

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

Dorn, Gerald W

2012-01-01

370

Cardiac pacing in infants and children.  

PubMed

Pacemakers have been implanted in pediatric patients since the late 1960s. Indications for cardiac pacing in infants and children have evolved to include controlling symptoms as well as providing a life-sustaining cardiac rhythm. Pacemakers have become smaller and able to perform more complex functions. Current pacemakers offer a variety of operation modes, which are chosen on the basis of the pacing indication or the potential hemodynamic benefit. Today's pacemakers have the ability to maintain AV synchrony, perform rate-responsive pacing, and sometimes prevent or treat tachyarrhythmias. Recent advances in pacing lead technology, such as steroid elution, have narrowed the gap between epicardial and endocardial leads in terms of chronic pacing thresholds and sensing characteristics. The choice of a permanent pacing system is determined by the patient's size, underlying arrhythmia, and the anatomic details of any structural heart disease. Selection of temporary pacing modalities depends on the urgency of initiating pacing and the anticipated duration of temporary pacing. The decision to implant a permanent pacemaker in a pediatric patient commits the patient to long-term follow-up of pacemaker function. Such follow-up is important to ensure adequate safety margins for pacing and sensing, anticipate the need for pacemaker replacement, screen for pacemaker malfunctions, and optimize programmable settings. Pediatric cardiac pacing has evolved into its own subspecialty over the past decade. As more infants with complex congenital heart disease are being successfully treated with surgical palliation and repair, the population of pediatric patients with permanent pacemakers is likely to increase. PMID:11174899

Sliz, N B; Johns, J A

2000-01-01

371

Modelling of an Oesophageal Electrode for Cardiac Function Tomography  

PubMed Central

There is a need in critical care units for continuous cardiopulmonary monitoring techniques. ECG gated electrical impedance tomography is able to localize the impedance variations occurring during the cardiac cycle. This method is a safe, inexpensive and potentially fast technique for cardiac output imaging but the spatial resolution is presently low, particularly for central locations such as the heart. Many parameters including noise deteriorate the reconstruction result. One of the main obstacles in cardiac imaging at the heart location is the high impedance of lungs and muscles on the dorsal and posterior side of body. In this study we are investigating improvements of the measurement and initial conductivity estimation of the internal electrode by modelling an internal electrode inside the esophagus. We consider 16 electrodes connected around a cylindrical mesh. With the random noise level set near 0.05% of the signal we evaluated the Graz consensus reconstruction algorithm for electrical impedance tomography. The modelling and simulation results showed that the quality of the target in reconstructed images was improved by up to 5 times for amplitude response, position error, resolution, shape deformation and ringing effects with perturbations located in cardiac related positions when using an internal electrode. PMID:22481975

Tehrani, J. Nasehi; Jin, C.; McEwan, A. L.

2012-01-01

372

X-ray source assembly having enhanced output stability, and fluid stream analysis applications thereof  

DOEpatents

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.

Radley, Ian (Glenmont, NY); Bievenue, Thomas J. (Delmar, NY); Burdett, John H. (Charlton, NY); Gallagher, Brian W. (Guilderland, NY); Shakshober, Stuart M. (Hudson, NY); Chen, Zewu (Schenectady, NY); Moore, Michael D. (Alplaus, NY)

2008-06-08

373

X-ray source assembly having enhanced output stability, and fluid stream analysis applications thereof  

DOEpatents

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.

Radley, Ian; Bievenue, Thomas J.; Burdett Jr., John H.; Gallagher, Brian W.; Shakshober, Stuart M.; Chen, Zewu; Moore, Michael D.

2007-04-24

374

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

NASA Astrophysics Data System (ADS)

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 ten 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.

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

2012-10-01

375

EGF is required for cardiac differentiation of P19CL6 cells through interaction with GATA-4 in a time- and dose-dependent manner.  

PubMed

The regulation of cardiac differentiation is critical for maintaining normal cardiac development and function. The precise mechanisms whereby cardiac differentiation is regulated remain uncertain. Here, we have identified a GATA-4 target, EGF, which is essential for cardiogenesis and regulates cardiac differentiation in a dose- and time-dependent manner. Moreover, EGF demonstrates functional interaction with GATA-4 in inducing the cardiac differentiation of P19CL6 cells in a time- and dose-dependent manner. Biochemically, GATA-4 forms a complex with STAT3 to bind to the EGF promoter in response to EGF stimulation and cooperatively activate the EGF promoter. Functionally, the cooperation during EGF activation results in the subsequent activation of cyclin D1 expression, which partly accounts for the lack of additional induction of cardiac differentiation by the GATA-4/STAT3 complex. Thus, we propose a model in which the regulatory cascade of cardiac differentiation involves GATA-4, EGF, and cyclin D1. PMID:25504289

Ma, Cai-Xia; Song, Yang-Liu; Xiao, Liyun; Xue, Li-Xiang; Li, Wen-Juan; Laforest, Brigitte; Komati, Hiba; Wang, Wei-Ping; Jia, Zhu-Qing; Zhou, Chun-Yan; Zou, Yunzeng; Nemer, Mona; Zhang, Shan-Feng; Bai, Xiaowen; Wu, Huijian; Zang, Ming-Xi

2015-05-01

376

Space Maintainers in Dentistry: Past to Present  

PubMed Central

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

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

2013-01-01

377

Designing for Maintainability and System Availability  

NASA Technical Reports Server (NTRS)

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.

Lalli, Vincent R.; Packard, Michael H.

1997-01-01

378

Space maintainers in dentistry: past to present.  

PubMed

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

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

2013-10-01

379

[Tolerance of +Gz accelerations in chronic compensated cardiac muscle disease].  

PubMed

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

Suvorov, P M; Bykova, Iu I

1975-01-01

380

Trends in cardiac pacemaker batteries.  

PubMed

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

Mallela, Venkateswara Sarma; Ilankumaran, V; Rao, N Srinivasa

2004-01-01

381

PREVIMER : Meteorological inputs and outputs  

NASA Astrophysics Data System (ADS)

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 which the system has been operational almost everyday and propose perspectives in terms of technical improvements and possible business models.

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

2009-09-01

382

Sudden Cardiac Arrest: ECG Repolarization after Resuscitation  

E-print Network

1 Sudden Cardiac Arrest: ECG Repolarization after Resuscitation Short title: sudden cardiac arrest;22(2):131-6" DOI : 10.1111/j.1540-8167.2010.01871.x #12;2 INTRODUCTION Out-of-hospital sudden cardiac arrest (OHCA after a cardiac arrest (5) and the prediction of an acute ischemic event from an ECG immediately

Paris-Sud XI, Université de

383

Cardiac cone-beam CT  

SciTech Connect

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

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

2005-10-15

384

Metoclopramide-induced cardiac arrest  

PubMed Central

The authors report a case of cardiac arrest in a patient receiving intravenous (IV) metoclopramide and review the pertinent literature. A 62-year-old morbidly obese female admitted for a gastric sleeve procedure, developed cardiac arrest within one minute of receiving metoclopramide 10 mg via slow intravenous (IV) injection. Bradycardia at 4 beats/min immediately appeared, progressing rapidly to asystole. Chest compressions restored vital function. Electrocardiogram (ECG) revealed ST depression indicative of myocardial injury. Following intubation, the patient was transferred to the intensive care unit. Various cardiac dysrrhythmias including supraventricular tachycardia (SVT) associated with hypertension and atrial fibrillation occurred. Following IV esmolol and metoprolol, the patient reverted to normal sinus rhythm. Repeat ECGs revealed ST depression resolution without pre-admission changes. Metoclopramide is a non-specific dopamine receptor antagonist. Seven cases of cardiac arrest and one of sinus arrest with metoclopramide were found in the literature. The metoclopramide prescribing information does not list precautions or adverse drug reactions (ADRs) related to cardiac arrest. The reaction is not dose related but may relate to the IV administration route. Coronary artery disease was the sole risk factor identified. According to Naranjo, the association was possible. Other reports of cardiac arrest, severe bradycardia, and SVT were reviewed. In one case, five separate IV doses of 10 mg metoclopramide were immediately followed by asystole repeatedly. The mechanism(s) underlying metoclopramide's cardiac arrest-inducing effects is unknown. Structural similarities to procainamide may play a role. In view of eight previous cases of cardiac arrest from metoclopramide having been reported, further elucidation of this ADR and patient monitoring is needed. Our report should alert clinicians to monitor patients and remain diligent in surveillance and reporting of bradydysrrhythmias and cardiac arrest in patients receiving metoclopramide. PMID:24765383

Rumore, Martha M.; Lee, Spencer Evan; Wang, Steven; Farmer, Brenna

2011-01-01

385

Cardiac action potential imaging  

NASA Astrophysics Data System (ADS)

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 ?M. 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.

Tian, Qinghai; Lipp, Peter; Kaestner, Lars

2013-06-01

386

Videoscope-assisted cardiac surgery  

PubMed Central

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

Chen, Robert Jeen-Chen

2014-01-01

387

Cardiac catheterization is underutilized after in-hospital cardiac arrest  

PubMed Central

Background Indications for immediate cardiac catheterization in cardiac arrest survivors without ST elevation myocardial infarction (STEMI) are uncertain as electrocardiographic and clinical criteria may be challenging to interpret in this population. We sought to evaluate rates of early catheterization after in-hospital ventricular fibrillation (VF) arrest and the association with survival. Methods Using a billing database we retrospectively identified cases with an ICD-9 code of cardiac arrest (427.5) or VF (427.41). Discharge summaries were reviewed to identify in-hospital VF arrests. Rates of catheterization on the day of arrest were determined by identifying billing charges. Unadjusted analyses were performed using chi square, and adjusted analyses were performed using logistic regression. Results 110 in-hospital VF arrest survivors were included in the analysis. Cardiac catheterization was performed immediately or within one day of arrest in 27% (30/110) of patients and of these patients, 57% (17/30) successfully received percutaneous coronary intervention. Of those who received cardiac catheterization the indication for the procedure was STEMI or new left bundle branch block (LBBB) in 43% (13/30). Therefore, in the absence of standard ECG data suggesting acute myocardial infarction, 57% (17/30) received angiography. Patients receiving cardiac catheterization were more likely to survive than those who did not receive catheterization (80% vs. 54%, p<.05). Conclusion In patients receiving cardiac catheterization, more than half received this procedure for indications other than STEMI or new LBBB. Cardiac catheterization was associated with improved survival. Future recommendations need to be established to guide clinicians on which arrest survivors might benefit from immediate catheterization. PMID:18951683

Merchant, Raina M.; Abella, Benjamin S.; Khan, Monica; Huang, Kuang-Ning; Beiser, David B.; Neumar, Robert W.; Carr, Brendan G.; Becker, Lance B.; Vanden Hoek, Terry L.

2009-01-01

388

Cardiac performance correlates of relative heart ventricle mass in amphibians.  

PubMed

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. PMID:23619575

Kluthe, Gregory J; Hillman, Stanley S

2013-08-01

389

Inaccurate calculation of drug output from nebulisers.  

PubMed

A multistage liquid impinger was used to collect the nebulised cloud from three separate nebulisers. The output of sodium cromoglycate collected was determined by a spectrophotometric assay. Estimating drug output purely from weight loss during nebulisation resulted in a considerable overestimate compared with direct assay of the drug output from the nebulised cloud. During nebulisation, weight loss from the nebuliser occurs in the form of particle formation and also by evaporation. By only weighing the nebuliser chamber before and after nebulisation, weight loss due to evaporation is not taken into account and this is the cause of the overestimation of drug output by this method. PMID:2493380

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

1989-02-01

390

PRODUCING SALMON TO MAINTAIN COMMERCIAL AND  

E-print Network

THIS IS A SALMO HATCH PRODUCING SALMON TO MAINTAIN COMMERCIAL AND SPORT FISHERIES SHKT* illiiniltiiiii SALMON HATCHERY? To maintain the resource, enough of the mature salmon entering and destroyed young salmon. To counteract the effects of these, salmon hatcheries are necessary. Hatchery salmon

391

Maintaining the Gains in Malaria Control  

E-print Network

Maintaining the Gains in Malaria Control Ethiopia | Rwanda | Senegal | Tanzania (Mainland and Zanzibar) COUNTRY BRIEFS September 2011 #12;#12;SEpTEMbER 2011 MainTaining ThE gainS in MalaRia conTRol | ExEcuTivE SuMMaRy | 3 Key messages · aggressive campaigns to scale up malaria control have led

Klein, Ophir

392

Maintaining Stream Statistics over Sliding Windows  

Microsoft Academic Search

We consider the problem of maintaining aggregates and statistics over data streams, with respect to the last N data elements seen so far. We refer to this model as the sliding window model. We consider the following basic problem: Given a stream of bits, maintain a count of the number of 1's in the last N elements seen from the

Mayur Datar; Aristides Gionis; Piotr Indyk; Rajeev Motwani

2002-01-01

393

Agent Program Planning Information Maintain No Gain  

E-print Network

, or as an Employee Wellness Program. The Maintain No Gain program can be flexible to meet the needs of the local groups, or for use in an employee wellness program or to start an employee wellness program. Agent Training Agents can be trained to deliver the Maintain No Gain program by participating in and/or viewing

394

Encapsulation method for maintaining biodecontamination activity  

DOEpatents

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.

Rogers, Robert D. (Idaho Falls, ID); Hamilton, Melinda A. (Idaho Falls, ID); Nelson, Lee O. (Idaho Falls, ID); Benson, Jennifer (Cockermouth, GB); Green, Martin J. (Wooton, GB); Milner, Timothy N. (Centerville, VA)

2002-01-01

395

Encapsulation method for maintaining biodecontamination activity  

DOEpatents

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.

Rogers, Robert D.; Hamilton, Melinda A.; Nelson, Lee O.; Benson, Jennifer; Green, Martin J.; Milner, Timothy N.

2006-04-11

396

Myocardial metabolism during hypoxia: Maintained lactate oxidation during increased glycolysis  

SciTech Connect

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.

Mazer, C.D.; Stanley, W.C.; Hickey, R.F.; Neese, R.A.; Cason, B.A.; Demas, K.A.; Wisneski, J.A.; Gertz, E.W. (Univ. of California, San Francisco (USA))

1990-09-01

397

Respirometric Oxidative Phosphorylation Assessment in Saponin-permeabilized Cardiac Fibers  

PubMed Central

Investigation of mitochondrial function represents an important parameter of cardiac physiology as mitochondria are involved in energy metabolism, oxidative stress, apoptosis, aging, mitochondrial encephalomyopathies and drug toxicity. Given this, technologies to measure cardiac mitochondrial function are in demand. One technique that employs an integrative approach to measure mitochondrial function is respirometric oxidative phosphorylation (OXPHOS) analysis. The principle of respirometric OXPHOS assessment is centered around measuring oxygen concentration utilizing a Clark electrode. As the permeabilized fiber bundle consumes oxygen, oxygen concentration in the closed chamber declines. Using selected substrate-inhibitor-uncoupler titration protocols, electrons are provided to specific sites of the electron transport chain, allowing evaluation of mitochondrial function. Prior to respirometric analysis of mitochondrial function, mechanical and chemical preparatory techniques are utilized to permeabilize the sarcolemma of muscle fibers. Chemical permeabilization employs saponin to selectively perforate the cell membrane while maintaining cellular architecture. This paper thoroughly describes the steps involved in preparing saponin-skinned cardiac fibers for oxygen consumption measurements to evaluate mitochondrial OXPHOS. Additionally, troubleshooting advice as well as specific substrates, inhibitors and uncouplers that may be used to determine mitochondria function at specific sites of the electron transport chain are provided. Importantly, the described protocol may be easily applied to cardiac and skeletal tissue of various animal models and human samples. PMID:21403632

Hughey, Curtis C.; Hittel, Dustin S.; Johnsen, Virginia L.; Shearer, Jane

2011-01-01

398

Cardiac Metabolism in Heart Failure - Implications beyond ATP production  

PubMed Central

The heart has a high rate of ATP production and turnover which is required to maintain its continuous mechanical work. Perturbations in ATP generating processes may therefore affect contractile function directly. Characterizing cardiac metabolism in heart failure revealed several metabolic alterations termed metabolic remodeling, ranging from changes in substrate utilization to mitochondrial dysfunction, ultimately resulting in ATP deficiency and impaired contractility. However, ATP depletion is not the only relevant consequence of metabolic remodeling during heart failure. By providing cellular building blocks and signaling molecules, metabolic pathways control essential processes such as cell growth and regeneration. Thus, alterations in cardiac metabolism may also affect the progression to heart failure by mechanisms beyond ATP supply. Our aim is therefore to highlight that metabolic remodeling in heart failure not only results in impaired cardiac energetics, but also induces other processes implicated in the development of heart failure such as structural remodeling and oxidative stress. Accordingly, modulating cardiac metabolism in heart failure may have significant therapeutic relevance that goes beyond the energetic aspect. PMID:23989714

Doenst, Torsten; Nguyen, T. Dung; Abel, E. Dale

2013-01-01

399

DISTRIBUTION OF CARDIAC OUTPUT DURING DIURNAL CHANGES IN ACTIVITY IN RATS  

EPA Science Inventory

The hepatotoxicity of carbon tetrachloride and chloroform in rats is increased when exposure occurs during the dark part of the lighting cycle when rats are more active. ats are used as surrogates for humans in toxicology, but have opposite activity patterns, with humans being ac...

400

Changes in cardiac output and tibial artery flow during and after progressive LBNP  

NASA Technical Reports Server (NTRS)

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.

1980-01-01

401

Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity  

NASA Technical Reports Server (NTRS)

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.

Verbanck, S.; Larsson, H.; Linnarsson, D.; Prisk, G. K.; West, J. B.; Paiva, M.

1997-01-01

402

Increased mediastinal pressure and decreased cardiac output during laparoscopic Nissen fundoplication  

Microsoft Academic Search

Background. Laparoscopic Nissen fundoplication (LNF) is gaining popularity. Although the hemodynamic effects of the typical pneumoperitoneum have been studied, the additional consequences of the hiatal dissection necessary for LNF have not.Methods. Seven female pigs were anesthetized, intubated, and ventilated with a volume ventilator and hemodynamic and mechanical pressure monitoring devices were placed. Pressures were recorded every 15 minutes for 1

Mark A Talamini; Mario Mendoza-Sagaon; Christopher A Gitzelmann; Syed Ahmad; Robert Moesinger; Michael Kutka; Thomas Toung

1997-01-01

403

42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.  

Code of Federal Regulations, 2012 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2012-10-01

404

42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.  

Code of Federal Regulations, 2011 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2011-10-01

405

42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.  

Code of Federal Regulations, 2014 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2014-10-01

406

42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.  

Code of Federal Regulations, 2010 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2010-10-01

407

42 CFR 410.49 - Cardiac rehabilitation program and intensive cardiac rehabilitation program: Conditions of coverage.  

Code of Federal Regulations, 2013 CFR

...prescribed exercise, cardiac risk factor...individual patient that includes...intensive cardiac rehabilitation, based on patient-centered...measures of exercise performance...Physician-prescribed exercise each day cardiac rehabilitation...tailored to the patients'...

2013-10-01

408

Cardiac Rehabilitation: Then and Now.  

ERIC Educational Resources Information Center

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)

Wilson, Philip K.

1988-01-01

409

Blood Conservation in Cardiac Surgery   

E-print Network

Cardiac surgery is traditionally a heavy user of blood and blood products. Until recently, the benefits of transfusion have been largely assumed and the risks relatively ignored. This has prompted us to examine new ways ...

Slight, Robert

2008-01-01

410

Image guidance in cardiac electrophysiology  

E-print Network

Cardiac arrhythmias are characterized by a disruption or abnormal conduction of electrical signals within the heart. Treatment of arrhythmias has dramatically evolved over the past half-century, and today, minimally-invasive ...

Malchano, Zachary John

2006-01-01

411

Therapeutic hypothermia after cardiac arrest.  

PubMed

Prognosis following out-of-hospital cardiac arrest is generally poor, which is mostly due to the severity of neuronal damage. Recently, the use of therapeutic hypothermia has gradually occupied an important role in managing neuronal injuries in some cases of cardiac arrests. Some of the clinical trials conducted in comatose post-resuscitation cardiac arrest patients within the last decade have shown induced hypothermia to be effective in facilitating neuronal function recovery. This method has since been adopted in a number of guidelines and protocols as the standard method of treatment in carefully selected patient groups. Patient inclusion criteria ensure that hypothermia-associated complications are kept to a minimum while at the same time maximizing the treatment benefits. In the present work, we have examined different aspects in the use of therapeutic hypothermia as a means of managing comatose patients following cardiac arrest. PMID:25281626

Alshimemeri, Abdullah

2014-01-01

412

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 ...

413

A new approach to rowing ergometry: establishing exercise intensity relative to maximum force output  

Microsoft Academic Search

Summary  The present experiment evaluated a new approach to establish exercise intensity during hydraulic rowing ergometry. In contrast to the traditional approach where exercise intensity is augmented by systematically increasing workload, the new procedure increments the intensity of exercise while maintaining a constant percentage of maximum force output. Ten college females exercised on a hydraulic rower that allowed for control of

Randall L. Jensen; Frank I. Katch

1991-01-01

414

A compact large Voltage-compliance high output-impedance programmable current source for implantable microstimulators  

Microsoft Academic Search

A new CMOS current source is described for biomedical implantable microstimulator applications, which utilizes MOS transistors in deep triode region as linearized voltage controlled resistors (VCR). The VCR current source achieves large voltage compliance, up to 97% of the supply voltage, while maintaining high output impedance in the 100 M? range to keep the stimulus current constant within 1% of

Maysam Ghovanloo; Khalil Najafi

2005-01-01

415

An early proof-of-concept of cardiac resynchronization therapy  

PubMed Central

Almost 50 years ago, we published detailed hemodynamic findings in a patient with heart failure and intermittent left bundle branch block. Delayed intraventricular conduction was consistently accompanied by an increased duration of left ventricular (LV) isometric contraction, a drop in systolic blood pressure, a rise in heart rate, and a drop in cardiac output. To our knowledge, this observation provided the first ever evidence that delayed mechanical LV contraction was associated with deterioration, and return to a normal pre-ejection phase with improvement in LV function. PMID:22216372

Bourassa, Martial G; Khairy, Paul; Roy, Denis

2011-01-01

416

An early proof-of-concept of cardiac resynchronization therapy.  

PubMed

Almost 50 years ago, we published detailed hemodynamic findings in a patient with heart failure and intermittent left bundle branch block. Delayed intraventricular conduction was consistently accompanied by an increased duration of left ventricular (LV) isometric contraction, a drop in systolic blood pressure, a rise in heart rate, and a drop in cardiac output. To our knowledge, this observation provided the first ever evidence that delayed mechanical LV contraction was associated with deterioration, and return to a normal pre-ejection phase with improvement in LV function. PMID:22216372

Bourassa, Martial G; Khairy, Paul; Roy, Denis

2011-12-26

417

Pulmonary Hypertension in Cardiac Surgery  

PubMed Central

Pulmonary hypertension is an important prognostic factor in cardiac surgery associated with increased morbidity and mortality. With the aging population and the associated increase severity of illness, the prevalence of pulmonary hypertension in cardiac surgical patients will increase. In this review, the definition of pulmonary hypertension, the mechanisms and its relationship to right ventricular dysfunction will be presented. Finally, pharmacological and non-pharmacological therapeutic and preventive approaches will be presented. PMID:21286273

Denault, André; Deschamps, Alain; Tardif, Jean-Claude; Lambert, Jean; Perrault, Louis

2010-01-01

418

Cardiac effects of noncardiac neoplasms  

SciTech Connect

Clinically significant cardiovascular abnormalities may occur as secondary manifestations of noncardiac neoplasms. The principal cardiac effects of noncardiac tumors include the direct results of metastases to the heart or lungs, the indirect effects of circulating tumor products (causing nonbacterial thrombotic endocarditis, myeloma-associated amyloidosis, pheochromocytoma-associated cardiac hypertrophy and myofibrillar degeneration, and carcinoid heart disease), and the undesired cardiotoxicities of chemotherapy and radiotherapy. 89 references.

Schoen, F.J.; Berger, B.M.; Guerina, N.G.

1984-11-01

419

Implantable Cardiac Rhythm Device Batteries  

Microsoft Academic Search

Batteries used for implantable cardiac rhythm devices are described herein. Fully implanted cardiac rhythm devices, pacemakers,\\u000a and defibrillators treat patients with various cardiomyopathies. Each of these devices contains a battery that supplies all\\u000a of the energy for device functions. As devices were developed with increased longevity, more features and reduced size, batteries\\u000a were designed with considerably greater energy and power.

Michael J. Root

2008-01-01

420

Cardiac manifestations in systemic sclerosis  

PubMed Central

Primary cardiac involvement, which develops as a direct consequence of systemic sclerosis (SSc), may manifest as myocardial damage, fibrosis of the conduction system, pericardial and, less frequently, as valvular disease. In addition, cardiac complications in SSc may develop as a secondary phenomenon due to pulmonary arterial hypertension and kidney pathology. The prevalence of primary cardiac involvement in SSc is variable and difficult to determine because of the diversity of cardiac manifestations, the presence of subclinical periods, the type of diagnostic tools applied, and the diversity of patient populations. When clinically manifested, cardiac involvement is thought to be an important prognostic factor. Profound microvascular disease is a pathognomonic feature of SSc, as both vasospasm and structural alterations are present. Such alterations are thought to predict macrovascular atherosclerosis over time. There are contradictory reports regarding the prevalence of atherosclerosis in SSc. According to some authors, the prevalence of atherosclerosis of the large epicardial coronary arteries is similar to that of the general population, in contrast with other rheumatic diseases such as rheumatoid arthritis and systemic lupus erythematosus. However, the level of inflammation in SSc is inferior. Thus, the atherosclerotic process may not be as aggressive and not easily detectable in smaller studies. Echocardiography (especially tissue Doppler imaging), single-photon emission computed tomography, magnetic resonance imaging and cardiac computed tomography are sensitive techniques for earlier detection of both structural and functional scleroderma-related cardiac pathologies. Screening for subclinical cardiac involvement via modern, sensitive tools provides an opportunity for early diagnosis and treatment, which is of crucial importance for a positive outcome. PMID:25276300

Lambova, Sevdalina

2014-01-01

421

21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).  

Code of Federal Regulations, 2011 CFR

...false External transcutaneous cardiac pacemaker (noninvasive). 870.5550 Section...5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device...

2011-04-01

422

21 CFR 870.5550 - External transcutaneous cardiac pacemaker (noninvasive).  

Code of Federal Regulations, 2013 CFR

...false External transcutaneous cardiac pacemaker (noninvasive). 870.5550 Section...5550 External transcutaneous cardiac pacemaker (noninvasive). (a) Identification. An external transcutaneous cardiac pacemaker (noninvasive) is a device...

2013-04-01

423

Estrogen-Related Receptor ? (ERR?) and ERR? Are Essential Coordinators of Cardiac Metabolism and Function.  

PubMed

Almost all cellular functions are powered by a continuous energy supply derived from cellular metabolism. However, it is little understood how cellular energy production is coordinated with diverse energy-consuming cellular functions. Here, using the cardiac muscle system, we demonstrate that nuclear receptors estrogen-related receptor ? (ERR?) and ERR? are essential transcriptional coordinators of cardiac energy production and consumption. On the one hand, ERR? and ERR? together are vital for intact cardiomyocyte metabolism by directly controlling expression of genes important for mitochondrial functions and dynamics. On the other hand, ERR? and ERR? influence major cardiomyocyte energy consumption functions through direct transcriptional regulation of key contraction, calcium homeostasis, and conduction genes. Mice lacking both ERR? and cardiac ERR? develop severe bradycardia, lethal cardiomyopathy, and heart failure featuring metabolic, contractile, and conduction dysfunctions. These results illustrate that the ERR transcriptional pathway is essential to couple cellular energy metabolism with energy consumption processes in order to maintain normal cardiac function. PMID:25624346

Wang, Ting; McDonald, Caitlin; Petrenko, Nataliya B; Leblanc, Mathias; Wang, Tao; Giguere, Vincent; Evans, Ronald M; Patel, Vickas V; Pei, Liming

2015-04-01

424

Cardiac effects of 3-iodothyronamine: a new aminergic system modulating cardiac function.  

PubMed

3-Iodothyronamine T1AM is a novel endogenous thyroid hormone derivative that activates the G protein-coupled receptor known as trace anime-associated receptor 1 (TAAR1). In the isolated working rat heart and in rat cardiomyocytes, T1AM produced a reversible, dose-dependent negative inotropic effect (e.g., 27+/-5, 51+/-3, and 65+/-2% decrease in cardiac output at 19, 25, and 38 microM concentration, respectively). An independent negative chronotropic effect was also observed. The hemodynamic effects of T1AM were remarkably increased in the presence of the tyrosine kinase inhibitor genistein, whereas they were attenuated in the presence of the tyrosine phosphatase inhibitor vanadate. No effect was produced by inhibitors of protein kinase A, protein kinase C, calcium-calmodulin kinase II, phosphatidylinositol-3-kinase, or MAP kinases. Tissue cAMP levels were unchanged. In rat ventricular tissue, Western blot experiments with antiphosphotyrosine antibodies showed reduced phosphorylation of microsomal and cytosolic proteins after perfusion with synthetic T1AM; reverse transcriptase-polymerase chain reaction experiments revealed the presence of transcripts for at least 5 TAAR subtypes; specific and saturable binding of [125I]T1AM was observed, with a dissociation constant in the low micromolar range (5 microM); and endogenous T1AM was detectable by tandem mass spectrometry. In conclusion, our findings provide evidence for the existence of a novel aminergic system modulating cardiac function. PMID:17284482

Chiellini, Grazia; Frascarelli, Sabina; Ghelardoni, Sandra; Carnicelli, Vittoria; Tobias, Sandra C; DeBarber, Andrea; Brogioni, Simona; Ronca-Testoni, Simonetta; Cerbai, Elisabetta; Grandy, David K; Scanlan, Thomas S; Zucchi, Riccardo

2007-05-01

425

Drosophila Models of Cardiac Disease  

PubMed Central

The fruit fly Drosophila melanogaster has emerged as a useful model for cardiac diseases, both developmental abnormalities and adult functional impairment. Using the tools of both classical and molecular genetics, the study of the developing fly heart has been instrumental in identifying the major signaling events of cardiac field formation, cardiomyocyte specification, and the formation of the functioning heart tube. The larval stage of fly cardiac development has become an important model system for testing isolated preparations of living hearts for the effects of biological and pharmacological compounds on cardiac activity. Meanwhile, the recent development of effective techniques to study adult cardiac performance in the fly has opened new uses for the Drosophila model system. The fly system is now being used to study long-term alterations in adult performance caused by factors such as diet, exercise, and normal aging. The fly is a unique and valuable system for the study of such complex, long-term interactions, as it is the only invertebrate genetic model system with a working heart developmentally homologous to the vertebrate heart. Thus, the fly model combines the advantages of invertebrate genetics (such as large populations, facile molecular genetic techniques, and short lifespan) with physiological measurement techniques that allow meaningful comparisons with data from vertebrate model systems. As such, the fly model is well situated to make important contributions to the understanding of complicated interactions between environmental factors and genetics in the long-term regulation of cardiac performance. PMID:21377627

Piazza, Nicole; Wessells, R.J.

2013-01-01

426

Dental considerations for cardiac surgery.  

PubMed

Many patients requiring cardiac surgery possess poor oral health. The presence of decayed teeth, untreated dental abscesses, and periodontitis can all represent potentially potent causes of an odontogenic infection. Ultimately, such an infection can have catastrophic consequences if it occurs during or soon after certain cardiac procedures. Since an association exists between poor oral hygiene and various systemic diseases, many patients scheduled for cardiac procedures inherently possess poor oral hygiene and untreated dental infections. Inadequate patient education, financial constraints, and dental phobia all serve as barriers for patients receiving routine intraoral care. Consequently, patients may unknowingly present for cardiac surgery with undetected oral infections that can magnify the likelihood of an adverse outcome, leading to increased costs, morbidity, and possibly mortality. It is recommended to view oral health in the perspective of systemic health, specifically, recognizing the deleterious impact that an untreated odontogenic infection can have upon cardiac surgery. Therefore, considering scheduling constraints and the urgency of the operation, if time and resources permit, then it is suggested that patients who undergo elective cardiac surgery should be screened preoperatively to ensure that any oral infection is diagnosed and definitively treated. Such an investment can yield significant improvements in surgical outcome and overall patient health. PMID:18778297

Yasny, Jeffrey S; White, Jennifer

2009-01-01

427

Notch signaling and cardiac repair  

PubMed Central

Notch signaling is critical for proper heart development and recently has been reported to participate in adult cardiac repair. Notch resides at the cell surface as a single pass transmembrane receptor, transits through the cytoplasm following activation, and acts as a transcription factor upon entering the nucleus. This dynamic and widespread cellular distribution allows for potential interactions with many signaling and binding partners. Notch displays temporal as well as spatial versatility, acting as a strong developmental signal, controlling cell fate determination and lineage commitment, and playing a pivotal role in embryonic and adult stem cell proliferation and differentiation. This review serves as an update of recent literature addressing Notch signaling in the heart, with attention to findings from non cardiac research that provide clues for further interpretation of how the Notch pathway influences cardiac biology. Specific areas of focus include Notch signaling in adult myocardium following pathologic injury, the role of Notch in cardiac progenitor cells with respect to differentiation and cardiac repair, crosstalk between Notch and other cardiac signaling pathways, and emerging aspects of noncanonical Notch signaling in heart. PMID:22465038

Gude, Natalie; Sussman, Mark

2012-01-01

428

Design of hydraulic output Stirling engine  

Microsoft Academic Search

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

W. M. Toscano; A. C. Harvey; K. Lee

1983-01-01

429