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Noninvasive Cardiac Output Assessment During Heart Surgery  

Microsoft Academic Search

Objective. To evaluate the reliability of a new noninvasivemethod for the assessment of cardiac output with the partial carbondioxide rebreathing technique. Methods. This technique wasapplied to patients undergoing heart surgery. Values of cardiac indexobtained with this equipment were compared with the artero-venousCO2 gradient, a reliable index of cardiovascular status.Positive and negative predictive values of the test were assessed.Results. A total

Piero Ceriana; Marco Maurelli; Antonio Braschi; Paola Baiardi; Donatella De Amici



Cardiac Output Assessed by Invasive and Minimally Invasive Techniques  

PubMed Central

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

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



Understanding cardiac output  

PubMed Central

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

Vincent, Jean-Louis



Cardiac output measurement in newborn infants using the ultrasonic cardiac output monitor: an assessment of agreement with conventional echocardiography, repeatability and new user experience  

Microsoft Academic Search

ObjectiveTo assess (1) agreement between the ultrasonic cardiac output monitor (USCOM) 1A device for measurement of cardiac output in newborn infants and conventional echocardiography (ECHO), (2) repeatability of USCOM measurements and (3) agreement between novice and expert users of the USCOM.DesignA prospective observational study.SettingThe Neonatal Unit at the Royal Children's Hospital, Melbourne, Australia.Patients56 term and near-term infants, with no evidence

Neil Patel; Melissa Dodsworth; John F Mills



Assessment of a cardiac output device using arterial pulse waveform analysis, Vigileo, in cardiac surgery compared to pulmonary arterial thermodilution.  


Many devices are available to assess cardiac output (CO) in critically ill patients and in the operating room. Classical CO monitoring via a pulmonary artery catheter involves continuous cardiac output (CCO) measurement. The second generation of Flotrac/Vigileo monitors propose an analysis of peripheral arterial pulse waves to calculate CO (APCO) without calibration. The aim of our study was to compare the CO between the Swan Ganz catheter and the VigileoT. In this observational study, nine patients undergoing coronary artery bypass grafting were prospectively included. APCO, mean (CCO) and instantaneous CO (ICO) were measured. Perioperative and postoperative assessments were performed up to 24 hours post-surgery. Measurements were recorded every minute, resulting in the collection of 6492 data pairs. Comparison of APCO and ICO showed a limited bias of -0.1 l/min but an important percentage error of 48%. Corresponding values were -0.1 l/min and 46% for the APCO versus CCO comparison, and 0 and 17% for ICO versus CCO comparison. Large inter-individual variability does exist. During cardiac surgery and after leaving the operating room, Vigileo is not clinically equivalent to continuous thermodilution by pulmonary artery catheter Nevertheless, the connection between CCO and ICO relates the difference between APCO and CCO more to the different algorithms used. Further efforts should be concentrated on assessing the ability of this device to track changes in cardiac output. PMID:20369763

Hamm, J B; Nguyen, B V; Kiss, G; Wargnier, J P; Jauffroy, A; Helaine, L; Arvieux, C C; Gueret, G



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

National Technical Information Service (NTIS)

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

H. Handelsman



Reliability of peak and maximal cardiac output assessed using thoracic bioimpedance in children  

Microsoft Academic Search

The purpose of this study was to evaluate the reliability of a thoracic electrical bioimpedance based device (PhysioFlow) for the determination of cardiac output and stroke volume during exercise at peak oxygen uptake (peak \\u000a in children. The reliability of peak \\u000a is also reported. Eleven boys and nine girls aged 10–11 years completed a cycle ergometer test to voluntary exhaustion on three

Joanne Welsman; Katie Bywater; Colin Farr; Deborah Welford; Neil Armstrong



A pilot assessment of the FloTrac TM cardiac output monitoring system  

Microsoft Academic Search

Objective  To compare measurement of cardiac output (CO) by means of the FloTracTM CO monitor with the pulmonary artery catheter (PAC).\\u000a \\u000a \\u000a \\u000a Design  Prospective observational study.\\u000a \\u000a \\u000a \\u000a Setting  Intensive care unit of a tertiary hospital.\\u000a \\u000a \\u000a \\u000a Patients  Six post-operative cardiac surgery patients with existing arterial cannulas and PACs.\\u000a \\u000a \\u000a \\u000a Interventions  Attachment of the FloTracTM CO monitor and transducer to an existing arterial cannula. Simultaneous measurements of CO, indexed to body

Helen Ingrid Opdam; Li Wan; Rinaldo Bellomo



Gated single photon emission tomography MIBI stress perfusion imaging for assessing cardiac output and index in obese and non-obese patients  

Microsoft Academic Search

Objective To compare cardiac index, (CI) [i.e. Cardiac output (CO) corrected for body surface area], stroke volume index (SVI) and left ventricular ejection fraction (LVEF) of obese and non obese patients using gated Gated Single Photon Emission Computed Tomography (SPECT) MIBI perfusion imaging. This was done in order to assess haemodynamic function, represented by CI and systolic function represented by

J. P. Coffey; J. C. Hill



Cardiac output: a view from Buffalo  

Microsoft Academic Search

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

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



Near continuous cardiac output by thermodilution.  


A new thermodilution method for frequent (near continuous) estimation of cardiac output, without manual injection of fluid into the blood, was tested. The method utilizes a pulmonary artery catheter equipped with a fluid filled heat exchanger. The technique is based on cyclic cooling of the blood in the right atrium and measurement of the temperature changes in the pulmonary artery. Using this technique, a new estimate of cardiac output can be obtained every 32 s. Cardiac output estimates, obtained for a running mean of three measurements with this method, were compared to the mean of three conventional thermodilution measurements. The measurements were obtained during short periods of stable respiration and circulation. In six pigs, we made 46 paired measurements of conventional thermodilution (TD) and near continuous (TDc) thermodilution. The cardiac output (COTD) ranged from 2.4-13.7 l/min (mean 5.4 l/min). The best linear fit through the paired data points was COTDc = -0.57 + 1.01 COTD. The mean difference between the methods was -0.50 l/min (S.D. = 0.39). The mean coefficient of variation of repeated measurements with the near continuous thermodilution was 3.6%. Considering changes of more than 0.25 l/min to be significant, all changes in cardiac output measured by conventional thermodilution were followed by the running mean of three near continuous thermodilution estimates. This study demonstrates the feasibility of the new method to monitor cardiac output, and to detect all changes greater than 0.25 l/min. PMID:9269617

Jansen, J R; Johnson, R W; Yan, J Y; Verdouw, P D



Rapid assessment of cardiac output and central blood volumes from indicator dilution curves without precalculation using programmable calculators.  


The program described here provides complete analysis of the indicator dilution curve by incorporating densitometric calibration and logarithmic downslope fit for the widely used Hewlett-Packard 67/97 hand calculator series. Densitometric sensitivity is calculated from the linear regression as the dye calibration factor; thus, direct entry of the dye curve deflections eliminate the necessity to precalculate curve concentration. The program displays appropriate sequential time intervals prompting deflection entry of the upslope and initial exponential downslope of the curve. The remainder of the curve is generated from the logarithmically extrapolated initial downslope, and the area of the curve is then obtained for calculation of cardiac output, mean transit time, and central blood volume. Programming versatility and the rapid (4--5 min) immediate analysis of indicator dilution curves are thus available. PMID:6993093

Cole, M A; Crawford, D W



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



Noninvasive Monitoring of Cardiac Output in Critically Ill Patients Using Transesophageal Doppler  

Microsoft Academic Search

Measurement of cardiac output using thermodilution technique in mechanically ventilated patients is associated with significant morbidity. The goal of the present study was to assess the validity of car- diac output measurement using transesophageal Doppler in critically ill patients. Forty-six patients from three different intensive care units underwent 136 paired cardiac output measurements using thermodilution (CO TH ) and transesophageal




Cardiac Output Measurement by Pulse Dye Densitometry: Comparison with Pulmonary Artery Thermodilution in Post-Cardiac Surgery Patients  

Microsoft Academic Search

Objective. Pulse-dye densitometry (PDD) could be a suitable, low-invasive alternative to thermodilution using a pulmonary artery catheter\\u000a (PAC) for monitoring cardiac output. The aim of our study was to assess the reproducibility and validity of PDD compared to\\u000a PAC-thermodilution. Methods. In 43 post-cardiac surgery patients, the mean of triplicate readings of cardiac output was assessed using both methods.\\u000a In a

Martijn Kroon; A. B. Johan Groeneveld; Yvo M. Smulders



Rapid cardiac-output measurement with ungated spiral phase contrast  

Microsoft Academic Search

An ungated spiral phase-contrast (USPC) method was used to measure cardiac output (CO) rapidly and conveniently. The USPC method, which was originally designed for small periph- eral vessels, was modified to assess CO by measuring flow in the ascending aorta (AA). The modified USPC used a 12-inter- leaf spiral trajectory to acquire full-image data every 283 ms with 2-mm spatial

Jong B. Park; Bob S. Hu; Steven M. Conolly; Krishna S. Nayak; Dwight G. Nishimura



Pulseco: a less-invasive method to monitor cardiac output from arterial pressure after cardiac surgery  

Microsoft Academic Search

BackgroundCardiac output is often monitored after cardiac operations with a pulmonary artery catheter. A new method has been introduced that measures cardiac output by lithium dilution (LiDCO) and uses these data to calibrate a system (PulseCO) that calculates cardiac output continuously from the energy of the arterial pressure waveform. It is unknown whether PulseCO measurements are valid early after cardiac

Timothy T Hamilton; Lynne M Huber; Michael E Jessen



A comparison of three minimally invasive cardiac output devices with thermodilution in elective cardiac surgery.  


This study compared the cardiac output responses to haemodynamic interventions as measured by three minimally invasive monitors (Oesophageal Doppler Monitor the VigileoFlotrac and the LiDCOrapid) to the responses measured concurrently using thermodilution, in cardiac surgical patients. The study also assessed the precision and bias of these monitors in relation to thermodilution measurements. After a fluid bolus of at least 250 ml, the measured change in cardiac output was different among the devices, showing an increase with thermodilution in 82% of measurements, Oesophageal Doppler Monitor 68%, VigileoFlotrac 57% and LiDCOrapid 41%. When comparing the test devices to thermodilution, the kappa statistic showed at best only fair agreement, Oesophageal Doppler Monitor 0.34, LiDCOrapid 0.28 and VigileoFlotrac -0.03. After vasopressor administration, there was also significant variation in the change in cardiac output measured by the devices. Using Bland-Altman analysis, the precision of the devices in comparison to thermodilution showed minimal bias, but wide limits of agreement with percentage errors of Oesophageal Doppler Monitor 64.5%, VigileoFlotrac 47.6% and LiDCOrapid 54.2%. These findings indicate that these three devices differ in their responses, do not always provide the same information as thermodilution and should not be used interchangeably to track cardiac output changes. PMID:22165352

Phan, T D; Kluger, R; Wan, C; Wong, D; Padayachee, A



Measurement of Stroke Volume and Cardiac Output Using Echocardiography and Doppler  

Microsoft Academic Search

\\u000a Cardiac output measurement is of prime importance in the hemodynamic assessment of patients with circulatory failure. It helps\\u000a distinguish the different types of shock and, more importantly, is crucial in discriminating between cardiac dysfunction and\\u000a failure and also in evaluating the impact of various interventions.\\u000a \\u000a \\u000a Different methods can be used to measure cardiac output or, more precisely, stroke volume since

Bernard P. Cholley


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



Reduced maximal cardiac output at altitude — mechanisms and significance  

Microsoft Academic Search

When a lowlander ascends to altitude and acclimatizes over days to weeks, both maximal exercise capacity and maximal cardiac output are reduced compared to sea level. Of the several possible mechanisms underlying this reduction of maximal cardiac output, the available data are interpreted as supporting the simplest hypothesis — that this merely reflects the reduced requirement for muscle blood flow

Peter D Wagner



Modelflow underestimates cardiac output in heat-stressed individuals  

PubMed Central

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

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



Gastric intramucosal pH: A predictor of survival in cardiac surgery patients with low cardiac output?  

Microsoft Academic Search

Objective: To assess the value of gastric intramucosal pH measurement in patients with low output after cardiac surgery.Design: Prospective clinical study.Setting: University hospital.Participants: Fifteen patients with low output after cardiac surgery were included. Those who survived the first postoperative day (n = 14) remained in the study.Interventions: Gastric intramucosal pH and arterial lactate concentrations were measured 6, 12, and 24

Hubert Böhrer; Heinfried Schmidt; Johann Motsch; René Gust; Alfons Bach; Eike Martin



The relationship between cardiac output and effective renal plasma flow in patients with cardiac disease  

Microsoft Academic Search

The relationship between effective renal plasma flow (ERPF) and cardiac output was examined in 46 patients (22 with congestive heart failure and 24 following cardiac surgical procedures) by simultaneously measuring the global ERPF by the single-injection method and cardiac output by the thermodilution method. Of the patients in the heart-failure group, 21 also had pulmonary artery end diastolic pressure (PAEDP)

David McGiffin; W. Newlon Tauxe; Clifton Lewis; Robert Karp; John Mantle



Evaluation of Noninvasive Cardiac Output Methods During Exercise.  

National Technical Information Service (NTIS)

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)...

A. D. Moore L. H. Barrows M. Rashid S. F. Siconolfi



High-Output Cardiac Failure Revealing Primary Plasma Cell Leukemia  

PubMed Central

High-output cardiac failure in multiple myeloma (MM) is related to arteriovenous shunting in bone infiltrate disease. We describe such a complication in a patient with primary plasma cell leukemia (pPCL) without bone disease. We review the mechanisms that could be involved. As previously described, traditional cardiac failure therapy is not effective. pPCL therapy should not be delayed.

Chaoui, Driss; Gallet, Bruno; Genet, Philippe; Mbungani, Babette; Al Jijakli, Ahmad; Arakelyan, Nina; Mesbah, Louisa; Sutton, Laurent



Clinical review: Positive end-expiratory pressure and cardiac output  

Microsoft Academic Search

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

Thomas Luecke; Paolo Pelosi



Cardiac output monitoring: aortic transpulmonary thermodilution and pulse contour analysis agree with standard thermodilution methods in patients undergoing lung transplantation  

Microsoft Academic Search

Purpose  The PiCCO System is a relatively new device allowing intermittent cardiac output monitoring by aortic transpulmonary thermodilution\\u000a technique (Aorta intermittent) and continuous cardiac output monitoring by pulse contour analysis (Aorta continuous). The\\u000a objective of this study was to assess the level of agreement of Aorta intermittent and Aorta continuous with intermittent\\u000a (PA intermittent) and continuous cardiac output (PA continuous) measured

Giorgio Della Rocca; Maria Gabriella Costa; Cecilia Coccia; Livia Pompei; Pierangelo Di Marco; Vincenzo Vilardi; Paolo Pietropaoli



Evaluation of heavy water for indicator dilution cardiac output measurement  

SciTech Connect

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

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



Minimally Invasive Monitoring of Cardiac Output in the Cardiac Surgery Intensive Care Unit  

Microsoft Academic Search

Cardiac output monitoring in the cardiac surgery patient is standard practice that is traditionally performed using the pulmonary\\u000a artery catheter. However, over the past 20 years, the value of pulmonary artery catheters has been challenged, with some authors\\u000a suggesting that its use might be not only unnecessary but also harmful. New minimally invasive devices that measure cardiac\\u000a output have become available.

Jamal A. Alhashemi; Maurizio Cecconi; Giorgio della Rocca; Maxime Cannesson; Christoph K. Hofer



Validation of a continuous, arterial pressure-based cardiac output measurement: a multicenter, prospective clinical trial  

Microsoft Academic Search

INTRODUCTION: The present study compared measurements of cardiac output by an arterial pressure-based cardiac output (APCO) analysis method with measurement by intermittent thermodilution cardiac output (ICO) via pulmonary artery catheter in a clinical setting. METHODS: The multicenter, prospective clinical investigation enrolled patients with a clinical indication for cardiac output monitoring requiring pulmonary artery and radial artery catheters at two hospitals

William T McGee; Jeffrey L Horswell; Joachim Calderon; Gerard Janvier; Tom Van Severen; Greet Van den Berghe; Lori Kozikowski



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

Microsoft Academic Search

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

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



Cardiac output, blood pressure variability, and cognitive decline in geriatric cardiac patients  

PubMed Central

OBJECTIVE To prospectively investigate whether baseline findings on specific cardiovascular indices are predictive of subsequent rate of decline in Attention-Executive-Psychomotor function in a cohort of ambulatory older adults with cardiovascular diseases (CVDs). METHODS One hundred seventy-two older adults with CVD were administered a neuropsychological battery of executive functions tests at study entry, and at 12 and 36 months thereafter. At study entry, they also underwent vascular assessments including cardiac output (CO), ejection fraction, blood pressure (BP), brachial artery reactivity, and carotid intima media thickness. Random coefficient regressions were used to investigate the effect of these cardiac indices on rate of decline in Attention-Executive-Psychomotor function. RESULTS Cardiac output, systolic BP variability, and diastolic BP variability predicted decline in Attention-Executive-Psychomotor function. Specifically, lower CO, reduced variability in systolic BP, and increased variability in diastolic BP were associated with a faster rate of decline in Attention-Executive-Psychomotor function. Mean resting systolic and diastolic blood pressure did not predict decline in Attention-Executive-Psychomotor function. CONCLUSION Decline in frontal-subcortical cognitive functions among patients with CVDs appears to be mediated by systemic hypoperfusion and variability in blood pressure. The precise nature of these relationships, especially with regard to blood pressure variability, is complex and demands continued investigation.

Okonkwo, Ozioma C.; Cohen, Ronald A.; Gunstad, John; Poppas, Athena



Rapid cardiac-output measurement with ungated spiral phase contrast.  


An ungated spiral phase-contrast (USPC) method was used to measure cardiac output (CO) rapidly and conveniently. The USPC method, which was originally designed for small peripheral vessels, was modified to assess CO by measuring flow in the ascending aorta (AA). The modified USPC used a 12-interleaf spiral trajectory to acquire full-image data every 283 ms with 2-mm spatial resolution. The total scan time was 5 s. For comparison, a triggered real-time (TRT) method was used to indirectly calculate CO by measuring left-ventricular (LV) volume. The USPC and TRT measurements from all normal volunteers agreed. In a patient with patent ductus arteriosus (PDA), high CO was measured with USPC, which agreed well with the invasive cardiac-catheterized measurement. In normal volunteers, CO dropped about 20-30% with Valsalva maneuvering, and increased about 100% after exercise. Continuous 28-s cycling between Valsalva maneuvering and free-breathing showed that USPC can temporally resolve physiological CO changes. PMID:16802317

Park, Jong B; Hu, Bob S; Conolly, Steven M; Nayak, Krishna S; Nishimura, Dwight G



Effect of an irregular ventricular rhythm on cardiac output  

Microsoft Academic Search

The results of this study suggest that a third mechanism for the reduction of cardiac output in patients with AF is irregularity of the ventricular rhythm. Catheter ablation of the AV junction and implantation of a rate-responsive pacemaker in patients with AF may offer hemodynamic benefit beyond rate control by eliminating the irregularity that is present with medical therapy or

Emile G. Daoud; Raul Weiss; Marwan Bahu; Bradley P. Knight; Frank Bogun; Rajiva Goyal; Mark Harvey; S. Adam Strickberger; K. Ching Man; Fred Morady



Noninvasive cardiac output estimation using a novel photoplethysmogram index  

Microsoft Academic Search

Cardiac output (CO) monitoring is essential for indicating the perfusion status of the human cardiovascular system under different physiological conditions. However, it is currently limited to hospital use due to the need for either skilled operators or big, expensive measurement devices. Therefore, in this paper we devise a new CO indicator which can easily be incorporated into existing wearable devices.

L. Wang; Emma Pickwell-MacPherson; Y. P. Liang; Y. T. Zhang



Applications of minimally invasive cardiac output monitors  

PubMed Central

Because of the increasing age of the population, critical care and emergency medicine physicians have seen an increased number of critically ill patients over the last decade. Moreover, the trend of hospital closures in the United States t imposes a burden of increased efficiency. Hence, the identification of devices that facilitate accurate but rapid assessments of hemodynamic parameters without the added burden of invasiveness becomes tantamount. The purpose of this review is to understand the applications and limitations of these new technologies.



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



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

Microsoft Academic Search

We have analysed the clinical agreement between two methods of continuous cardiac output measurement: pulse contour analysis (PCCO) and a continuous thermodilution technique (CCO), were both compared with the intermittent bolus thermodilution technique (BCO). Measurements were performed in 26 cardiac surgical patients (groups 1 and 2, 13 patients each, with an ejection fraction .45% and ,45%, respectively) at 12 selected

G. Rodig; C. Prasser; C. Keyl; A. Liebold; J. Hobbhahn



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.

Luecke, Thomas; Pelosi, Paolo



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


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

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



Effects of vasopressin on left anterior descending coronary artery blood flow during extremely low cardiac output  

Microsoft Academic Search

Because of the possibility of vasopressin-mediated coronary vasospasm, this study was designed to assess effects of vasopressin compared to saline placebo on left anterior descending (LAD) coronary artery blood flow. Twelve anaesthetized domestic swine were prepared for LAD coronary artery blood flow measurement with ultrasonic flow probes, using cardiopulmonary by-pass adjusted to 10% of the prearrest cardiac output. This 10%

Viktoria D Mayr; Volker Wenzel; Tilko Müller; Herwig Antretter; Klaus Rheinberger; Karl H Lindner; Hans-Ulrich Strohmenger



Erroneous continuous cardiac output by calibrated pulse contour analysis.  


Pulse contour analysis techniques are used for beat-to-beat tracking of cardiac output in critically ill patients. However, an adequate pulse pressure waveform signal and identification of the appropriate (i.e. systolic) part of the waveform by the monitor are crucial for correct calculation of continuous cardiac output. We observed a case where the monitor failed to correctly identify the systolic part of the waveform during tachycardia thus giving false readings. We would like to emphasize the importance of visually checking the waveform for any irregularities that may cause erroneous calculations before initiating a therapy based on these values. One advantage of the system used here is that the part of the pressure curve used for analysis is automatically indicated. PMID:23604580

Grensemann, Jörn; Wappler, Frank; Sakka, Samir G



Errors in the measurement of cardiac output by thermodilution  

Microsoft Academic Search

Cardiac output (CO) determination by thermodilution, which was introduced by Fegler in 1954, has gained wide acceptance in\\u000a clinical medicine and animal experiments because it has several advantages over other methods with respect to simplicity,\\u000a accuracy, reproducibility, repeated measurements at short intervals, and because there is no need for blood withdrawal. However,\\u000a errors in determination of CO by thermodilution may

Toshiaki Nishikawa; Shuji Dohi



Cardiac Output and Central Blood Volume as a Function of Body Weight in the Baboon.  

National Technical Information Service (NTIS)

The relationship between cardiac output and central blood volume as a function of body weight was investigated in tranquilized adult baboons. Cardiac output was determined by the dye dilution method. Central blood volume was calculated as the product of c...



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

PubMed Central

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

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



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.

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



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

Microsoft Academic Search

INTRODUCTION: Continuous cardiac output monitoring is used for early detection of hemodynamic instability and guidance of therapy in critically ill patients. Recently, the accuracy of pulse contour-derived cardiac output (PCCO) has been questioned in different clinical situations. In this study, we examined agreement between PCCO and transcardiopulmonary thermodilution cardiac output (COTCP) in critically ill patients, with special emphasis on norepinephrine

Matthias Gruenewald; Patrick Meybohm; Jochen Renner; Ole Broch; Amke Caliebe; Norbert Weiler; Markus Steinfath; Jens Scholz; Berthold Bein



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


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



Continuous and intermittent cardiac output measurement in hyperdynamic conditions: pulmonary artery catheter vs. lithium dilution technique  

Microsoft Academic Search

Objective  This study aimed to assess the level of agreement of both intermittent cardiac output monitoring by the lithium dilution technique\\u000a (COLi) and continuous cardiac output monitoring (PulseCOLi) using the arterial pressure waveform with intermittent thermodilution using a pulmonary artery catheter (COPAC).\\u000a \\u000a \\u000a \\u000a Design  Prospective, single-center evaluation.\\u000a \\u000a \\u000a \\u000a Setting  University Hospital Intensive Care Unit.\\u000a \\u000a \\u000a \\u000a Patients  Patients (n?=?23) receiving liver transplantation.\\u000a \\u000a \\u000a \\u000a Intervention  Pulmonary artery catheters were placed in all

Maria Gabriella Costa; Giorgio Della Rocca; Paolo Chiarandini; Silvia Mattelig; Livia Pompei; Mauricio Sainz Barriga; Toby Reynolds; Maurizio Cecconi; Paolo Pietropaoli



Arterial pressure waveform derived cardiac output FloTrac/Vigileo system (third generation software): comparison of two monitoring sites with the thermodilution cardiac output.  


The present study was conducted to study the effect of monitoring site, radial or femoral, for arterial pressure waveform derived cardiac output using FloTrac/Vigileo system with third generation software version 3.02 during cardiac surgery. The cardiac output derived from the two sites was also compared to the pulmonary artery catheter (PAC) derived cardiac output to reevaluate the relation between them using the newer software. The effect of cardiopulmonary bypass (CPB) was also studied by doing the sub analysis before and after bypass. Forty patients undergoing coronary artery bypass surgery with cardiopulmonary bypass were enrolled in the study. Cardiac output derived from radial artery (RADCO), femoral artery (FEMCO) using FloTrac/Vigileo system with third generation software version 3.02 and cardiac output using pulmonary artery catheter (PACCO) at predefined nine time points were recorded. Three hundred and forty two cardiac output data triplets were analysed. The Bland-Altman analysis of RADCO and FEMCO revealed a mean bias of -0.28 with percentage error of 20%. The pre CPB precision of both RADCO and FEMCO was 1.25 times as that of PACCO. The post CPB precision of FEMCO was 1.2 times of PACCO while that of RADCO was 1.7 times of PACCO. The third generation of FloTrac/Vigileo system shows good correlation between the radial and femoral derived cardiac outputs in both pre and post bypass periods. The newer software correlates better to PAC derived cardiac output in the post bypass period for femoral artery than radial artery. PMID:22350311

Vasdev, Sumit; Chauhan, Sandeep; Choudhury, Minati; Hote, Millind P; Malik, Madhur; Kiran, Usha



Physiologic and Clinical Principles behind Noninvasive Resuscitation Techniques and Cardiac Output Monitoring.  


Clinical assessment and vital signs are poor predictors of the overall hemodynamic state. Optimal measurement of the response to fluid resuscitation and hemodynamics has previously required invasive measurement with radial and pulmonary artery catheterization. Newer noninvasive resuscitation technology offers the hope of more accurately and safely monitoring a broader range of critically ill patients while using fewer resources. Fluid responsiveness, the cardiac response to volume loading, represents a dynamic method of improving upon the assessment of preload when compared to static measures like central venous pressure. Multiple new hemodynamic monitors now exist that can noninvasively report cardiac output and oxygen delivery in a continuous manner. Proper assessment of the potential future role of these techniques in resuscitation requires understanding the underlying physiologic and clinical principles, reviewing the most recent literature examining their clinical validity, and evaluating their respective advantages and limitations. PMID:21860802

Napoli, Anthony M



Alpha-adrenergic regulation of splanchnic volume and cardiac output in the dog.  


The present study examined whether alpha-adrenergic stimulation causes a change in splanchnic intravascular volume in the anaesthetized animal with an intact circulation, which region(s) mediate the volume change, and whether the splanchnic volume change influences cardiac output. In order to ascertain that a radionuclide imaging technique could be used to assess total splanchnic volume changes, drugs known to increase or decrease splanchnic volume were infused on 21 occasions in eight dogs studied under conditions of selective perfusion and drainage of the splanchnic vasculature with erythrocytes labelled with 99Tcm and a gamma camera placed over the abdomen. For these 21 infusions, volume and radionuclide count changes were related: r greater than or equal to 0.90 (n = 20), r = 0.76 (n = 1). After ascertaining tissue attenuation and blood radioactivity in four of the animals, the standard error for a single estimate of the absolute volume change using the radionuclide technique was determined to be 75 ml. In six animals with intact circulations, phenylephrine (40-80 micrograms min-1) for 20 min was associated with an increase in cardiac output of 12 +/- 2% (P less than 0.001) and a decrease in total splanchnic volume estimated to be 431 +/- 95 ml (P less than 0.001). The splanchnic volume decrease was due entirely to decreases in splenic and intestinal volume. In eight eviscerated animals, cardiac output decreased by 30 +/- 2% (P less than 0.001) during phenylephrine.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2158209

Bell, L; Hennecken, J; Zaret, B L; Rutlen, D L



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


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

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



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

PubMed Central

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



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



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



The relationship between the flow of arteriovenous fistula and cardiac output in haemodialysis patients  

Microsoft Academic Search

Background. Satisfactory haemodialysis (HD) vascular access flow (Qa) is necessary for dialysis adequacy. High Qa is postulated to increase cardiac output (CO) and cause high-output cardiac failure. Aim of the present prospective study was to evaluate the relation- ship between Qa of arteriovenous fistulas (AVFs) and CO in order to have a closer insight into this scarcely explored aspect of

Carlo Basile; Carlo Lomonte; Luigi Vernaglione; Francesco Casucci; Maurizio Antonelli; Nicola Losurdo



Performance of a minimally invasive uncalibrated cardiac output monitoring system (FlotracTM\\/VigileoTM) in haemodynamically unstable patients  

Microsoft Academic Search

Background. Early haemodynamic assessment is of particular importance in the evaluation of haemodynamically compromised patients, but is often precluded by the invasiveness and com- plexity of the established cardiac output (CO) monitoring techniques. The FloTrac TM \\/Vigileo TM system allows minimally invasive CO determination based on the arterial pressure waveform derived from any standard arterial catheter, and the algorithm underlying

F. D. Compton; B. Zukunft; C. Hoffmann; W. Zidek; J.-H. Schaefer



Accuracy of a Novel Approach to Measuring Arterial Thermodilution Cardiac Output During Intra-Aortic Counterpulsation  

Microsoft Academic Search

Objective  To assess the agreement between a novel approach of arterial and the pulmonary artery bolus thermodilution for measuring cardiac\\u000a output in critically ill patients during aortic counterpulsation.\\u000a \\u000a \\u000a \\u000a Methods  Eighteen male patients aged 37–80 years, undergoing preoperative insertion of an intra-aortic balloon pump (IABP) and elective\\u000a coronary artery bypass grafting. A thin 1.3FG thermistor was introduced through the pressure lumen to the tip

Werner Baulig; Philipp Schuett; Oliver Goedje; Edith R. Schmid



Continuous monitoring of cardiac output from TCG signals.  


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

Keenan, D B



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



Lithium Dilution Cardiac Output Measurements Using a Peripheral Injection Site: Comparison with Central Injection Technique and Thermodilution  

Microsoft Academic Search

Objective. The lithium dilution technique for the measurement of cardiac output by the central injection of lithium chloride was introduced by Linton et al. in 1993. In the present report, we compare lithium dilution cardiac output measurement (LD) by the peripheral injection of lithium chloride (pLD) and by central venous injection (cLD), cardiac output determined by electromagnetic flowmetry (EM), and

Tadayoshi Kurita; Koji Morita; Shigeru Kato; Hiroyuki Kawasaki; Mutsuhito Kikura; Tomiei Kazama; Kazuyuki Ikeda



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

SciTech Connect

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

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



Validation of a Modified One-Step Rebreathing Technique for Measuring Exercise Cardiac Output.  

National Technical Information Service (NTIS)

A modification of the Farhi one-step rebreathing technique is described for determining submaximal exercise cardiac output (Q). Factors critical in the estimation of Q are initial rebreathing bag volume and constant bag volume during the maneuver. By subs...

P. C. Szlyk K. C. Evans I. V. Sils



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


The time constant for heat transfer may affect exact determination of cardiac output with Swan-Ganz catheters. Commercially available Swan-Ganz catheters are provided with thermistors with varying time constants. Current monitoring of cardiac output is not corrected for these time constants, so the conventional method of determining cardiac output using the equation of Stewart-Hamilton produces marked errors. The authors propose a new method of determining cardiac output with Swan-Ganz catheters with varying time constants from thermal dilution curve data based on Newton's cooling law. Values for blood flow rate determined by the new method using a completely stirred tank of original design, mimicking the natural heart and using bovine blood, are almost the same as values observed at varying saline infusion volumes, saline temperatures, and saline infusion times. PMID:2252783

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


Continuous measurement of cardiac output with the use of stochastic system identification techniques  

Microsoft Academic Search

The limitations of developing a technique to measure cardiac output continuously are given. Logical explanations are provided\\u000a for the economic, technical, and physiologic benefits of a stochastic system identification technique for measuring cardiac\\u000a output. Heat is supplied by a cathetermounted filament driven according to a pseudorandom binarsequence. Volumetric fluid\\u000a flow is derived by a crosscorrelation algorithm written in the C

Mark Yelderman



Measurement of extravascular lung water by thermal-dye dilution technique: Mechanisms of cardiac output dependence  

Microsoft Academic Search

The extent to which extravascular lung water (EVLW) is dependent on cardiac output was analysed in anaesthetized and mechanically ventilated pigs. EVLW was measured by thermal-dye dilution technique, by a fibreoptic thermistor catheter system (system 1), and by a thermistor catheter-external optical cuvette system (system 2). During baseline conditions, at which cardiac output was 3.65 l\\/min, EVLW was 11.7 and

C.-J. Wickerts; J. Jakobsson; C. Frostell; G. Hedenstierna



Volume loading improves low cardiac output in experimental right ventricular infarction. [Dogs  

SciTech Connect

To evaluate the effect of volume loading in the low output state associated with right ventricular infarction, isolated right ventricular infarction was produced in seven dogs with the pericardium intact. Volume loading and pericardiotomy were then sequentially performed. After the production of right ventricular infarction, right ventricular systolic pressure decreased by 25%, aortic pressure by 36% and cardiac output by 32%. Right ventricular ejection fraction decreased by 57%, but left ventricular ejection fraction did not change significantly. Left ventricular transmural pressure and diastolic size decreased, and right ventricular diastolic size increased. Intrapericardial pressure increased and equalization of diastolic pressures was noted. Volume loading resulted in increased right ventricular systolic pressure and stroke work, increased aortic pressure and cardiac output and increased transmural pressure and diastolic size in both ventricles. Pericardiotomy resulted in further increases in right and left ventricular filling, stroke work and cardiac output, as well as resolution of equalized diastolic pressures. These results indicate that cardiac output in experimental right ventricular infarction increases with volume loading, which enhances left ventricular preload by augmenting right ventricular output. Elevated intrapericardial pressure affects filling of both ventricles and may play a role in the pathophysiology of low cardiac output in right ventricular infarction.

Goldstein, J.A.; Vlahakes, G.J.; Verrier, E.D.; Schiller, N.B.; Botvinick, E.; Tyberg, J.V.; Parmley, W.W.; Chatterjee, K.



Sonographic assessment of fetal cardiac function: introduction and direct measurement of cardiac function.  


Noninvasive blood flow measurements based on Doppler ultrasound studies are the main clinical tool for studying the cardiovascular status in fetuses at risk for circulatory compromise. Usually, qualitative analysis of peripheral arteries and, in particular clinical situations such as severe growth restriction or volume overload, also of venous vessels close to the heart or of flow patterns in the heart are being used to gauge the level of compensation in a fetus. Quantitative assessment of the driving force of the fetal circulation, the cardiac output, however, remains an elusive goal in fetal medicine. This article reviews the methods for direct and indirect assessment of cardiac function and explains new clinical applications. Part 1 of this review describes the concept of cardiac function and cardiac output and the techniques that have been used to quantify output. Part 2 summarizes the use of arterial and venous Doppler studies in the fetus and gives a detailed description of indirect measures of cardiac function (like indices derived from the duration of segments of the cardiac cycle) with current examples of their application. PMID:21614744

Tutschek, B; Schmidt, K G



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

PubMed Central

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

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



Assessment of global cardiac function.  


High-resolution magnetic resonance cine imaging (cine-MRI) allows for a non-invasive assessment of ventricular function and mass in normal mice and in genetically and surgically modified mouse models of cardiac disease. The assessment of myocardial mass and function by cine-MRI does not rely on geometric assumptions, as the hearts are covered from the base to the apex, typically by a stack of two-dimensional images. The MR data acquisition is then followed by image segmentation of specific cine frames in each slice to obtain geometric and functional parameters, such as end-diastolic volume (EDV), end-systolic volume (ESV) or ejection fraction (EF). This technique has been well established in clinical routine application and it is now also becoming the reference method in experimental cardiovascular MRI. The cine images are typically acquired in short- and long-axis orientations of the heart to facilitate an accurate assessment of cardiac functional parameters. These views can be difficult to identify, particularly in animals with diseased hearts. Furthermore, data analysis can be the source of a systematic error, mainly for myocardial mass measurement. We have established protocols that allow for a quick and reproducible way of obtaining the relevant cardiac views for cine-MRI, and for accurate image analysis. PMID:21874489

Schneider, Jürgen E



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

PubMed Central

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

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



Validation of a new spectrometer for noninvasive measurement of cardiac output  

NASA Astrophysics Data System (ADS)

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

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



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

PubMed Central

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

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



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.

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



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

Microsoft Academic Search

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

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



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

Microsoft Academic Search

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 (fc) showed an initial bradycardia. The lowest

P. Vogelaere; G. Deklunder; J. Lecroart



Comparison between Flotrac-Vigileo and Bioreactance, a totally noninvasive method for cardiac output monitoring  

Microsoft Academic Search

ABSTRACT: INTRODUCTION: This study was designed to compare the clinical acceptability of two cardiac output (CO) monitoring systems: a pulse wave contour-based system (FloTrac-Vigileo) and a bioreactance-based system (NICOM), using continuous thermodilution (PAC-CCO) as a reference method. METHODS: Consecutive patients, requiring PAC-CCO monitoring following cardiac surgery, were also monitored by the two other devices. CO values obtained simultaneously by the

Sophie Marqué; Alain Cariou; Jean-Daniel Chiche; Pierre Squara



Effects of cardiac output on disposition kinetics of sorbitol: recirculatory modelling.  


1. The purpose of this study was to determine the effects of cardiac output on distribution and elimination kinetics of the marker compound sorbitol. 2. The disposition kinetics of sorbitol were investigated after rapid intravenous injection and arterial sampling in nine patients who had undergone cardiac catheterization whereby the cardiac output was measured. 3. A minimal circulatory model consisting of pulmonary and systemic subsystems, both of which were characterized by an inverse Gaussian transit time density function, fitted the data very well. The method involves numerical inverse Laplace transform of the model equations. 4. The mixing clearance introduced as a novel non-compartmental parameter of distribution dynamics was significantly correlated with cardiac output. The steady-state volume of 14 l matched the extracellular volume. The systemic extraction ratio of 23% may reflect the fractional liver blood flow. 5. This pharmacokinetic model can be applied when an independent observation of cardiac output is available. In contrast to the conventional compartmental (or sum of exponential) approach it contains fewer adjustable parameters which can be more readily interpreted in physiological terms. PMID:8730970

Weiss, M; Hübner, G H; Hübner, I G; Teichmann, W



Lack of reliability of cardiac output measurements derived from arterial pressure waveform analysis in on-pump cardiac surgery patients  

Microsoft Academic Search

\\u000a The arterial pressure waveform-based device for cardiac output (CO) measurement FloTrac\\/VigileoTM offers the possibility of minimal-invasive CO monitoring without the need for invasive calibration. The agreement of the\\u000a results of this device with bolus thermodilution remains controversialas is the choice of the best arterial cannulation site.\\u000a \\u000a \\u000a After approval of the local ethics committee 14 Patients scheduled for elective cardiac surgery

S. Eleftheriadis; M. Heringlake; K.-U. Berger; H. V. Groesdonk; J. Schoen


Comparison of calibrated and uncalibrated arterial pressure-based cardiac output monitors during orthotopic liver transplantation.  


Arterial pressure-based cardiac output monitors (APCOs) are increasingly used as alternatives to thermodilution. Validation of these evolving technologies in high-risk surgery is still ongoing. In liver transplantation, FloTrac-Vigileo (Edwards Lifesciences) has limited correlation with thermodilution, whereas LiDCO Plus (LiDCO Ltd.) has not been tested intraoperatively. Our goal was to directly compare the 2 proprietary APCO algorithms as alternatives to pulmonary artery catheter thermodilution in orthotopic liver transplantation (OLT). The cardiac index (CI) was measured simultaneously in 20 OLT patients at prospectively defined surgical landmarks with the LiDCO Plus monitor (CI(L)) and the FloTrac-Vigileo monitor (CI(V)). LiDCO Plus was calibrated according to the manufacturer's instructions. FloTrac-Vigileo did not require calibration. The reference CI was derived from pulmonary artery catheter intermittent thermodilution (CI(TD)). CI(V)-CI(TD) bias ranged from -1.38 (95% confidence interval = -2.02 to -0.75 L/minute/m(2), P = 0.02) to -2.51 L/minute/m(2) (95% confidence interval = -3.36 to -1.65 L/minute/m(2), P < 0.001), and CI(L)-CI(TD) bias ranged from -0.65 (95% confidence interval = -1.29 to -0.01 L/minute/m(2), P = 0.047) to -1.48 L/minute/m(2) (95% confidence interval = -2.37 to -0.60 L/minute/m(2), P < 0.01). For both APCOs, bias to CI(TD) was correlated with the systemic vascular resistance index, with a stronger dependence for FloTrac-Vigileo. The capability of the APCOs for tracking changes in CI(TD) was assessed with a 4-quadrant plot for directional changes and with receiver operating characteristic curves for specificity and sensitivity. The performance of both APCOs was poor in detecting increases and fair in detecting decreases in CI(TD). In conclusion, the calibrated and uncalibrated APCOs perform differently during OLT. Although the calibrated APCO is less influenced by changes in the systemic vascular resistance, neither device can be used interchangeably with thermodilution to monitor cardiac output during liver transplantation. PMID:20517912

Krejci, Vladimir; Vannucci, Andrea; Abbas, Alhan; Chapman, William; Kangrga, Ivan M



Distribution of cardiac output during pentobarbital versus midazolam\\/fentanyl\\/fluanisone anaesthesia in the rat  

Microsoft Academic Search

Summary Differences in effects on central haemodynamics, organ blood flow, and serum corticosterone were studied in 11 rats anaesthetized with midazolam\\/ fentanyl\\/fluanisone (MFF) and 11 other rats anaesthetized with sodium pentobarbital. Compared with pentobarbital, MFF reduced aortic blood pressure by 250\\/0, increased heart rate by 20%, and increased cardiac output by 80%. Unlike most tissues, MFF produced a fivefold increase

Knut C. Skolleborg; Jon E. Grönbech; Ketil Grong; Frank E. Åbyholm; Jon Lekven



Cardiac output distribution and uteroplacental blood flow in the pregnant rabbit: a comparative study  

SciTech Connect

This study presents data on cardiac output distribution and uterine and placental blood flows in pregnant rabbits under chronic steady-state conditions. Ten litters and 67 fetuses were studied at 29 days of gestation, by means of radioactive microspheres. Five nonpregnant female animals were also studied for comparison. Mean cardiac outputs were 747.16 +/- 55.7 and 613.80 +/- 63.76 ml/min in the pregnant and nonpregnant states, respectively. In the pregnant animals, uterine and mammary blood flows were 6.7% +/- 0.7% and 5.1% +/- 0.5% of cardiac output, respectively. Within litters, the highest placental blood flows occurred at the ovarian and vaginal ends of the uterine horn. Placental blood flow per gram of fetus was 0.106 +/- 0.008 ml X min-1 X gm-1. A comparison with analogous data in the guinea pig and sheep demonstrates that toward the end of pregnancy placental blood flow per gram of fetus is approximately 2.5-times higher in sheep than in rabbits and guinea pigs. Expressed as a percentage of cardiac output, near-term uterine blood flow is significantly less in rabbits than in guinea pigs and sheep, whereas mammary blood flow is significantly higher. These interspecies differences are related to differences in placental structure, fetal/maternal mass ratio, and maturity at birth.

Johnson, R.L.; Gilbert, M.; Meschia, G.; Battaglia, F.C.



Effect of region of interest selection on first-pass radionuclide cardiac output determination  

SciTech Connect

In principle, region of interest (ROI) selection should not affect the measurement of cardiac output by the first-pass technique with a radioactive intravascular indicator. Clinical application of the method requires that this theoretical hypothesis be tested. Sixty-eight left anterior oblique first-pass studies were acquired with a scintillation camera and computer using red blood cells labeled in vitro with /sup 99m/Tc. Calculated mean cardiac output varied in the following order with respect to ROI: lung greater than right heart greater than left ventricle greater than whole heart (both ventricles) greater than aorta. Similar variations were observed in patients both with and without valvular regurgitation. Regions of interest over left ventricle or whole heart yielded the best correlations with cardiac output by thermodilution (r = 0.96, 0.95, respectively, n = 28) as well as the smallest interobserver variations (r = 0.994, 0.995, respectively, n = 33). First-pass studies with (/sup 99m/Tc)red blood cells labeled in vitro can yield accurate, reproducible determinations of cardiac output provided that the effect of ROI selection is recognized and that regions are properly selected.

Glass, E.C.; Rahimian, J.; Hines, H.H.



Improvement of cardiac output estimation by the thermodilution method during mechanical ventilation  

Microsoft Academic Search

The reliability of cardiac output estimation by thermodilution during artificial ventilation was studied in anesthetized pigs at the right side of the heart. The estimates exhibited a cyclic modulation related to the ventilation. The amplitude of the modulation was independent of the level of positive end-expiratory pressure, ventilatory pattern and volemic loading of the animals. However, a non-constant phase relation

J. R. C. Jansen; A. Versprille



Precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation  

Microsoft Academic Search

Background: The precision of bolus thermodilution cardiac output measurements in patients with atrial fibrillation (AF) has not previously been determined. A priori we suspected that the precision would be lower in patients with AF than in patients with sinus rhythm (SR). Consequently, we also deter- mined if the precision could be improved by injecting the thermal indicator into the right




Model reference adaptive control of cardiac output and blood pressure through two drug infusions  

Microsoft Academic Search

Control of blood pressure and cardiac output, with dopamine and sodium nitroprusside has been achieved using a model reference adaptive controller. A procedure for selecting the adaptation weights for a 2×2 system has been developed. Satisfactory model following has occurred despite time delays that caused stability criteria to be violated. The structure of the plant prohibited zero steady state error

Elisa Hope Barney; Howard Kaufman



Lithium dilution cardiac output measurement in oleic acid–induced pulmonary edema  

Microsoft Academic Search

Objective: To determine whether lung injury influences the accuracy of lithium dilution cardiac output (CO) measurement. Design: Animal experimental study. Setting: Animal experimental laboratory. Participants: Swine (n = 23) weighing 26.4 ± 2.47 kg (mean ± SD). Interventions: The animals were anesthetized and tracheotomized, then a pulmonary artery catheter was inserted into the right jugular vein, and a catheter (18G)

Tadayoshi Kurita; Koji Morita; Hiroyuki Kawasaki; Kiyoyasu Fujii; Tomiei Kazama; Shigehito Sato



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

Microsoft Academic Search

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

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


Comparison of electrical velocimetry and transoesophageal Doppler echocardiography for measuring stroke volume and cardiac output  

Microsoft Academic Search

Background. Impedance cardiography (ICG) has been used extensively to estimate stroke volume (SV) and cardiac output (CO) from changes of thoracic electrical bioimpedance (TEB). However, studies comparing ICG with reference methods have questioned the reliability of this approach. Electrical velocimetry (EV) provides a new algorithm to calculate CO from variations in TEB. As the transoesophageal Doppler echocardiographic quantification of CO

C. Schmidt; G. Theilmeier; H. Van Aken; P. Korsmeier; S. P. Wirtz; E. Berendes; A. Hoffmeier; A. Meissner



Continuous and intermittent cardiac output measurement: pulmonary artery catheter versus aortic transpulmonary technique  

Microsoft Academic Search

Background. Cardiac output (CO) can be measured intermittently by bolus thermodilution methods in the pulmonary artery (COpa) or in the aorta (COart). A continuous thermodilu- tion method (CCO) and a method for continuous estimation using the arterial pulse wave (PCCO) are also available. Methods. We compared two methods of intermittent CO measurements in patients during liver transplantation: COpa, regarded as

G. Della Rocca; L. Pompei; C. Cocci; P. Pietropaoli



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

PubMed Central

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



Beat-to-beat measurement of cardiac output by intravascular pulse contour analysis: A prospective criterion standard study in patients after cardiac surgery  

Microsoft Academic Search

Objective: To evaluate the accuracy of a new pulse contour method of measuring cardiac output in critically ill patients. p ]Design: A prospective criterion standard study. p ]Setting: Cardiac surgery intensive care unit in a university hospital. p ]Participants: Nineteen cardiac surgery patients requiring intensive care treatment with pulmonary artery catheters after surgery. p ]Interventions: None. p ]Measurements and Main

Christian Zöllner; Mathias Haller; Marion Weis; Karl Mörstedt; Peter Lamm; Erich Kilger; Alwin E. Goetz



A Meta-Analysis of Studies Using Bias and Precision Statistics to Compare Cardiac Output Measurement Techniques  

Microsoft Academic Search

Introduction. Bias and precision statistics have succeeded regression analysis when measurement techniques are compared. However, when applied to cardiac output measurements, inconsistencies occur in reporting the results of this form of analysis. Methods. A MEDLINE search was performed, dating from 1986. Studies comparing techniques of cardiac output measurement using bias and precision statistics were surveyed. An error-gram was constructed from

Lester A. H. Critchley; Julian A. J. H. Critchley



The decrease of cardiac chamber volumes and output during positive-pressure ventilation.  


Positive-pressure ventilation (PPV) is widely used for treatment of acute cardiorespiratory failure, occasionally at the expense of compromised cardiac function and arterial blood pressure. The explanation why has largely rested on interpretation of intracardiac pressure changes. We evaluated the effect of PPV on the central circulation by studying cardiac chamber volumes with cardiac magnetic resonance imaging (CMR). We hypothesized that PPV lowers cardiac output (CO) mainly via the Frank-Starling relationship. In 18 healthy volunteers, cardiac chamber volumes and flow in aorta and the pulmonary artery were measured by CMR during PPV levels of 0, 10, and 20 cmH2O applied via a respirator and a face mask. All cardiac chamber volumes decreased in proportion to the level of PPV. Following 20-cmH2O PPV, the total diastolic and systolic cardiac volumes (±SE) decreased from 605 (±29) ml to 446 (±29) ml (P < 0.001) and from 265 (±17) ml to 212 (±16) ml (P < 0.001). Left ventricular stroke volume decreased by 27 (±4) ml/beat; heart rate increased by 7 (±2) beats/min; and CO decreased by 1.0 (±0.4) l/min (P < 0.001). From 0 to 20 cmH2O, right and left ventricular peak filling rates decreased by -146 (±32) and -187 (±64) ml/s (P < 0.05) but maximal emptying rates were unchanged. Cardiac filling and output decrease with increasing PPV in healthy volunteers. The decrease is seen even at low levels of PPV and should be taken into account when submitting patients to mechanical ventilation with positive pressures. The decrease in CO is fully explained by the Frank-Starling mechanism. PMID:23893161

Kyhl, Kasper; Ahtarovski, Kiril Aleksov; Iversen, Kasper; Thomsen, Carsten; Vejlstrup, Niels; Engstrøm, Thomas; Madsen, Per Lav



Arterial pressure-based cardiac output in septic patients: different accuracy of pulse contour and uncalibrated pressure waveform devices  

Microsoft Academic Search

INTRODUCTION: We compared the ability of two devices estimating cardiac output from arterial pressure-curve analysis to track the changes in cardiac output measured with transpulmonary thermodilution induced by volume expansion and norepinephrine in sepsis patients. METHODS: In 80 patients with septic circulatory failure, we administered volume expansion (40 patients) or introduced\\/increased norepinephrine (40 patients). We measured the pulse contour-derived cardiac

Xavier Monnet; Nadia Anguel; Brice Naudin; Julien Jabot; Christian Richard; Jean-Louis Teboul



First-pass radionuclide determination of cardiac output: an improved gamma camera method  

SciTech Connect

A technique for noninvasive determination of cardiac output by aid of first-pass radionuclide cardiography is described. After intravenous injection of 10-15 mCi technetium-99m-(99mTc) labeled red blood cells the method requires acquisition of a first passage time-activity curve recorded with a gamma camera over the left ventricle, the background corrected left ventricular count rate recorded after complete mixing of the tracer in the circulation, and determination of the distribution volume of the tracer. The method was applied in 14 patients with heart disease of various origins and evaluated against the conventional tracer dilution technique with arterial sampling of blood activity. Cardiac output determinations by external counting ranged from 2.30 to 8.56 l/min, mean +/- s.d. 4.50 +/- 1.66 l/min and by arterial blood sampling from 1.88 to 8.96 l/min, mean +/- s.d. 4.52 +/- 1.71 l/min. An excellent correlation was demonstrated between the two techniques, r = 0.978 (p less than 0.001). When no background subtraction was applied to the left ventricular counts at equilibrium, radionuclide cardiac output values were approximately 40% higher than those obtained by arterial sampling. The new first-pass radionuclide cardiographic technique may prove a useful tool in the noninvasive evaluation of cardiac function, especially in patients with arrhythmias and/or valvular incompetence.

Kelbaek, H.; Hartling, O.J.; Skagen, K.; Munck, O.; Henriksen, O.; Godtfredsen, J.



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


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

Peyton, Philip J



Bench-to-bedside review: The importance of the precision of the reference technique in method comparison studies – with specific reference to the measurement of cardiac output  

Microsoft Academic Search

Bland-Altman analysis is used for assessing agreement between two measurements of the same clinical variable. In the field of cardiac output monitoring, its results, in terms of bias and limits of agreement, are often difficult to interpret, leading clinicians to use a cutoff of 30% in the percentage error in order to decide whether a new technique may be considered

Maurizio Cecconi; Andrew Rhodes; Jan Poloniecki; Giorgio Della Rocca; R Michael Grounds



Cardiothoracic Anesthesia, Respiration and Airway Cardiac output by PulseCO ™ is not interchangeable with thermodilution in patients undergoing OPCAB  

Microsoft Academic Search

Purpose  To investigate the reliability of cardiac output assessed by arterial pressure waveform (PulseCO™) in comparison with bolus thermodilution measurements in patients undergoing off-pump coronary artery bypass grafting (OPCAB).\\u000a \\u000a \\u000a \\u000a Methods  23 patients who underwent OPCAB were enrolled in this study. After premedication with oral diazepam 10 mg, anesthesia was\\u000a induced with midazolam, fentanyl and vecuronium. After induction, radial artery and pulmonary artery

Koichi Yamashita; Tomoki Nishiyama; Takeshi Yokoyama; Hidehiro Abe; Masanobu Manabe



Enhanced cardiac thermal dilution analysis for cardiac output, volumes, stroke volumes, and regurgitation rates--sensitivity analysis using digital simulation.  


Cardiac output is measured by placing a double lumen catheter with a thermistor on the tip through the right ventricle into the pulmonary artery, injecting cold saline into the right atrium, and integrating the resulting pulmonary artery temperature profile. If a similar procedure is performed with thermistors located in the right atrium, right ventricle, and pulmonary artery, the resulting temperature curves are determined by the known or easily measured quantities: injectate temperature, injectate volume, heart rate, systolic time interval, body temperature, and time in the cardiac cycle at which injection begins and the unknown quantities: right atrial, right ventricular, pulmonary artery mean and stroke volumes, inflow and outflow valve regurgitation rates, and cardiac output. A digital computer program using a lumped parameter model has been developed to use these quantities to produce thermal dilution curves and optimize the fit of the model curves to the temperature curves from the thermal dilution measurement to determine the unknown quantities. The program is used to investigate the effects of measuring system time constant, heat transfer, and noise on the accuracy of these measurements. The results indicate that the method is practical. PMID:10999367

Donovan, F M; Taylor, B C



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


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

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



In vitro approach to study the influence of the cardiac output distribution on drug concentration  

Microsoft Academic Search

Summary  Blood flow is not constant during the day, not only due to cardiac output variation but to the variable blood flow fraction\\u000a supplied to the organs. To what extent these variations could affect the relative drug concentration between two different\\u000a tissues, is the purpose of this work. In order to study that, a device was designed which took into account

P. Fagiolino; F. Wilson; E. Samaniego; M. Vázquez



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

Microsoft Academic Search

Pacific tarpon (Megalops cyprinoides) use a modified gas bladder as an air-breathing organ (ABO). We examined changes in cardiac output (V?b) associated with increases in air-breathing that accompany exercise and aquatic hypoxia. Juvenile (0.49 kg) and adult (1.21 kg) tarpon were allowed to recover in a swim flume at 27 °C after being instrumented with a Doppler flow probe around the ventral aorta

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



Comparison of pulmonary artery and arterial thermodilution cardiac output in critically ill patients  

Microsoft Academic Search

Objective: We studied the agreement between cardiac output measurements via pulmonary artery thermodilution [CO(PA)], regarded as the\\u000a current clinical gold standard, and aortic transpulmonary thermodilution [CO(AORTA)]. Design: Prospective clinical study. Setting: Surgical intensive care unit of a university hospital. Patients: 37 patients with sepsis or septic shock (n = 34) and subarachnoid haemorrhage (n = 3). Measurements and results: We

S. G. Sakka; K. Reinhart; A. Meier-Hellmann



Temporal stability of ambulatory stroke volume and cardiac output measured by impedance cardiography  

Microsoft Academic Search

Recently, devices have become available that allow non-invasive measurement of stroke volume and cardiac output through ambulatory thorax impedance recording. If such recordings have adequate temporal stability, they offer great potential to further our understanding of how repeated or chronic cardiovascular activation in response to naturalistic events may contribute to cardiovascular disease. In this study, 24h ambulatory impedance-derived systolic time

Annebet D. Goedhart; Nina Kupper; Gonneke Willemsen; Dorret I. Boomsma; Eco J. C. de Geus



Flow velocity profile of the pulmonary artery measured by the continuous cardiac output monitoring catheter  

Microsoft Academic Search

The KATS catheter (continuous arterial thermodeprivation system catheter) measures the blood flow velocity of the pulmonary\\u000a artery (PA) by thermodeprivation which enables continuous determination of cardiac output. The accuracy of this system may\\u000a depend on the degree of uniformity of flow velocity in the PA, because small movements of the catheter within the PA are inevitable\\u000a with a beating heart.

Keiko Miyasaka; Masao Takata; Katsuyuki Miyasaka MO



Transpulmonary thermodilution cardiac output measurement using the axillary artery in critically ill patients  

Microsoft Academic Search

Study Objective: To compare cardiac output (CO) as measured by the arterial thermodilution technique using only a central venous catheter and an arterial catheter inserted into the axillary artery, with conventional CO measurement with thermodilution using a pulmonary artery (PA) catheter (PAC).Design: Prospective clinical study in which each patient served as his\\/her own control.Setting: General ICU of a large tertiary-care

Eran Segal; Rita Katzenelson; Haim Berkenstadt; Azriel Perel



Measurement of cardiac output by transesophageal echocardiography in mechanically ventilated patients  

Microsoft Academic Search

Objective: The determination of basal cardiac output (CO) and of its variations during different therapeutic interventions liable to\\u000a increase or decrease it in mechanically ventilated patients using transesophageal echocardiography (TEE). Design: To compare CO measurements simultaneously obtained by transmitral single-plane TEE and thermodilution. Setting: Medical intensive care unit. Patients: Twenty-two consecutive mechanically ventilated patients hospitalized for various medical conditions were

P. Estagnasié; K. Djedaini; L. Mier; F. Coste; D. Dreyfuss



Multiple-model adaptive predictive control of mean arterial pressure and cardiac output  

Microsoft Academic Search

A multiple-model adaptive predictive controller has been designed to simultaneously regulate mean arterial pressure and cardiac output in congestive heart failure subjects by adjusting the infusion rates of nitroprusside and dopamine. The algorithm is based on the multiple-model adaptive controller and utilizes model predictive controllers to provide reliable control in each model subspace. A total of 36 linear small-signal models

Clement Yu; Rob J. Roy; Howard Kaufman; B. Wayne Bequette



Pressure Pulse Contour-derived Stroke Volume and Cardiac Output in the Morbidly Obese Patient  

Microsoft Academic Search

Background  The pressure pulse contour method for measuring stroke volume (SV) and cardiac output (CO) has come of age. Various methods\\u000a have been proposed, but at this time no single technique has shown clear superiority over the others. This commentary and\\u000a review discusses the various methods, and particularly the pressure recording analytical method (PRAM). Dissection of the\\u000a method shows that vascular

Donald P. Bernstein



Measurement of cardiac output using near-infrared heating of blood  

NASA Astrophysics Data System (ADS)

Thermodilution-based cardiac output measurements are made using iced saline or blood heated by resistive heating as a dilutable indicator. Because near-infrared irradiation penetrates sufficiently deeply into blood, it can safely deposit up to six times the energy of a resistive heater, improving the accuracy of the measurements while continuously monitoring cardiac output. We have developed a prototype system using 980 nm diode lasers to irradiate blood through a diffuser. This system was tested using an optical blood phantom and was compared to iced-saline injection and resistive heating. Three flow estimates were made at each of 18 combinations of stroke rate, stroke volume, and systole/diastole ratios. Accuracy was determined by the quality of the fit between the estimated flows and the actual flow. Reproducibility was determined by the normalized standard deviation. Results: Measurements made by saline injection were the most accurate (R2 equals 0.982) and reproducible (NSD equals 2.8%). Power limitations on the resistive heating to ensure a safe blood temperature limited its accuracy (R2 equals 0.537) and reproducibility (NSD equals 18.1%). Laser-based heating showed reasonable accuracy and reproducibility (R2 equals 0.950, NSD equals 7.8%). Laser heating thus represents a potentially more accurate alternative to saline injection for cardiac output measurement than does resistive heating.

Curley, Michael G.; Hamilton, Patrick S.; Walsh, Joseph T.



Delayed time response of the continuous cardiac output pulmonary artery catheter.  


Previous studies of the accuracy of pulmonary artery catheters (PAC) which provide continuous cardiac output (CCO) monitoring have investigated the performance during steady-state conditions. We compared the response time to hemodynamic change using a CCO PAC and an ultrasonic flow probe (UFP). In five sheep, a CCO PAC was inserted, and an UFP for measurement of CCO was placed around the pulmonary artery via a left thoracotomy. Six interventions which rapidly alter cardiac output were studied: crystalloid bolus, balloon inflation in the inferior vena cava (IVC), IVC balloon deflation, dobutamine infusion, hemorrhage, and reinfusion of blood. Cardiac output measured before and after each intervention was used to calculate the total change caused by the intervention, and the time intervals from intervention to 20%, 50%, and 80% of that change were noted. For all interventions, the time response of CCO was significantly slower than UFP. The largest differences were seen with the rapid infusion of lactated Ringer's solution for which the time interval for 20% change was 7.3 +/- 2.3 min (mean +/- SD) for CCO versus 0.5 +/- 0.3 min for UFP. The time interval for 80% change was 14.5 +/- 4.1 min for CCO versus 1.8 +/- 0.9 min with UFP. The current study demonstrates clinically important time delays in the response of the CCO catheter. This delay must be considered when rapid alterations of the hemodynamic state may occur. PMID:8942581

Siegel, L C; Hennessy, M M; Pearl, R G



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.



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

PubMed Central

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

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



The influence of nonlinear intra-thoracic vascular behaviour and compression characteristics on cardiac output during CPR.  


Clinical observations suggest that the assumption of a linear relationship between chest compression pressure and cardiac output may be oversimplified. More complex behaviour may occur when the transmural pressure is large, changing the compliances and resistances in the intra-thoracic vasculature. A fundamental understanding of these compression induced phenomena is required for improving CPR. An extensively used, lumped element computer model (model I) of the circulation was upgraded and refined to include the intrathoracic vasculature (model II). After validation, model II was extended by adding variable compliances and resistances (model III) to the vascular structures. Successively, ranges of compression pressures, frequencies, duty cycles and compression pulse shapes were applied while controlling all other parameters. Cardiac output was then compared. The nonlinearities in compliance and resistance become important, limiting factors in cardiac output, starting in our experimental series at 70 mmHg peak compression pressure, and increasing with higher pressures. This effect is reproducible for sinusoidal and trapezoidal compression forms, resulting in lower cardiac output in all experiments at high compression pressures. Duty cycle and wait time are key parameters for cardiac output. Our data strongly indicate that vascular compliance, especially the ability of vessels to collapse (and potentially the cardiac chambers), can be a central factor in the limited output generated by chest compressions. Just pushing 'harder' or 'faster' is not always better, as an 'optimal' force and frequency may exist. Overly forceful compression can limit blood flow by restricting filling or depleting volume in the cardiac chambers and central great vessels. PMID:21324578

Koeken, Yvette; Aelen, Paul; Noordergraaf, Gerrit J; Paulussen, Igor; Woerlee, Pierre; Noordergraaf, Abraham



Evaluation of impedance cardiography as a non-invasive means of measuring systolic time intervals and cardiac output.  


Impedance cardiography was used for non-invasive determinations of systolic time intervals (STI) and cardiac output. The results were compared with simultaneously obtained invasive measurements of STI from central aortic pressure curves and of cardiac output using the dye-dilution technique. The study was performed on eight dogs during increasing halothane concentration. A close correlation was found between non-invasively and invasively measured left ventricular ejection time = LVET (r = 0.986) and pre-ejection period - PEP (r - 0.948). Measurements of cardiac output derived from changes in thoracic impedance were determined 1) using a fixed value of p (p - the resistivity of blood) and 2) using an individual value of p based on the actual hematocrits. When compared to cardiac outputs obtained by dye-dilution the correlation coefficients were r = 0.806 and r = 0.816, respectively. Impedance cardiography is a useful method of evaluating changes in cardiac output. The method permits simultaneous observations of changes in STI and cardiac output as an index of cardiac function. PMID:1101602

Rasmussen, J P; Sorensen, B; Kann, T



Reduced central blood volume and cardiac output and increased vascular resistance during static handgrip exercise in postural tachycardia syndrome.  


Postural tachycardia syndrome (POTS) is characterized by exercise intolerance and sympathoactivation. To examine whether abnormal cardiac output and central blood volume changes occur during exercise in POTS, we studied 29 patients with POTS (17-29 yr) and 12 healthy subjects (18-27 yr) using impedance and venous occlusion plethysmography to assess regional blood volumes and flows during supine static handgrip to evoke the exercise pressor reflex. POTS was subgrouped into normal and low-flow groups based on calf blood flow. We examined autonomic effects with variability techniques. During handgrip, systolic blood pressure increased from 112 +/- 4 to 139 +/- 9 mmHg in control, from 119 +/- 6 to 143 +/- 9 in normal-flow POTS, but only from 117 +/- 4 to 128 +/- 6 in low-flow POTS. Heart rate increased from 63 +/- 6 to 82 +/- 4 beats/min in control, 76 +/- 3 to 92 +/- 6 beats/min in normal-flow POTS, and 88 +/- 4 to 100 +/- 6 beats/min in low-flow POTS. Heart rate variability and coherence markedly decreased in low-flow POTS, indicating uncoupling of baroreflex heart rate regulation. The increase in central blood volume with handgrip was absent in low-flow POTS and blunted in normal-flow POTS associated with abnormal splanchnic emptying. Cardiac output increased in control, was unchanged in low-flow POTS, and was attenuated in normal-flow POTS. Total peripheral resistance was increased compared with control in all POTS. The exercise pressor reflex was attenuated in low-flow POTS. While increased cardiac output and central blood volume characterizes controls, increased peripheral resistance with blunted or eliminated in central blood volume increments characterizes POTS and may contribute to exercise intolerance. PMID:17616747

Stewart, Julian M; Taneja, Indu; Medow, Marvin S



Mathematical basis for the measurement of absolute and fractional cardiac output with diffusible tracers by compartmental analysis methods  

SciTech Connect

Using compartmental analysis methods, a mathematical basis is given for the measurement of absolute and fractional cardiac output with diffusible tracers. Cardiac output is shown to be the product of the blood volume and the sum of the rate constants of tracer egress from blood, modified by a factor reflecting transcapillary diffusibility, the transfer fraction. The return of tracer to the blood and distant (intracellular) events are shown to play no role in the solution. Fractional cardiac output is the ratio of the rate constant of tracer egress from blood to an organ, divided by the sum of the egress constants from blood. Predominantly extracellular ions such as sodium or bromide are best suited for this technique, although theoretically any diffusible tracer whose compartmental model can be solved may be used. It is shown that fractional cardiac output is independent of the transfer fraction, and therefore can be measured accurately by tracers which are not freely diffusible.

Charkes, N.D.



Reliability of Cardiac Output Calculation by the Fick Principle and Central Venous Oxygen Saturation in Emergency Conditions  

Microsoft Academic Search

Background  For many years thermodilution has been the gold standard for determining cardiac output in the critically ill patients. Less\\u000a invasive methods have recently been introduced. This study aimed at evaluating the agreement between cardiac output (CO) measured\\u000a by a new Fick method, using central venous saturation (Scvo2), and that measured by the classic thermodilution technique, in patients requiring emergent CO

Avi A. Weinbroum; Philippe Biderman; Dror Soffer; Joseph M. Klausner; Oded Szold



Accuracy of an indirect carbon dioxide Fick method in determination of the cardiac output in critically ill mechanically ventilated patients  

Microsoft Academic Search

We evaluated the accuracy of an indirect CO2 Fick method for measuring cardiac output in 30 critically ill mechanically ventilated patients. When the Fick principle was applied to CO2 using estimated PaCO2, the cardiac output obtained underestimated the thermodilution technique showing a lack of accuracy. However, there was a significant correlation between thermodilution and CO2 rebreathing methods using measured (r=0.92;

L. Blanch; R. Fernfindez; S. Benito; J. Mancebo; N. Calaf; A. Net



Transpulmonary transit of microbubbles during contrast echocardiography: implications for estimating cardiac output and pulmonary blood volume.  


We postulated that the pulmonary transit rate of sonicated albumin microbubbles, which have an intravascular rheology similar to that of red blood cells, would be directly proportional to cardiac output (CO) and inversely proportional to pulmonary blood volume (PBV). Accordingly, 4 ml of Albunex ultrasound contrast agent (0.5 billion/ml of 4.3 mu bubbles) was injected into the right atrium of six dogs (Group I) during simultaneously performed two-dimensional echocardiography, and the time between the initial appearance of the bubbles in the right and left ventricle, respectively, was measured. CO was either increased (by intravenous infusion of 15 micrograms/kg/min of dobutamine) or decreased (by producing left ventricular ischemia or by administering 2 mg of intravenous propranolol) in a random order and microbubbles were injected again. At each stage, thermodilution CO was measured. There was a close linear relation between CO and pulmonary transit rate of Albunex in each dog with the correlation coefficient ranging from 0.79 to 0.99, with a mean of 0.92. Pulmonary blood volume was derived in each dog from the reciprocal of the slope of the regression between CO and pulmonary transit rate and varied from 106 to 261 ml in the six dogs with a mean value of 178 +/- 64 ml. There was excellent interobserver and intraobserver correlation (r = 0.99 each) for determining the pulmonary transit rate of Albunex. The reproducibility of pulmonary transit rate estimation from repeated contrast injections at the same hemodynamic state in another group of six dogs (Group II) was also good (r = 0.99). It is concluded that the pulmonary transit rate of Albunex ultrasound contrast agent can be used to assess directional changes in CO and to measure pulmonary blood volume. This method may have clinical applications. PMID:8333975

Galanti, G; Jayaweera, A R; Villanueva, F S; Glasheen, W P; Ismail, S; Kaul, S


Cardiac risk assessment before non-cardiac surgery.  


Cardiovascular events account for half of the deaths related to non-cardiac surgery. Identification of a patient's risk and perioperative management appropriate to that risk is important to optimize the clinical outcome of surgery. Key concepts of preoperative cardiac risk assessment are contained within American and European guidelines. Risk indices stratify patients according to clinical and surgery-specific predictors. The most widely used is the Lee index; however, all have limitations. Patients at intermediate and high risk following risk index stratification and assessment of functional capacity require further non-invasive assessment to detect myocardial ischaemia using, for instance, exercise electrocardiography, myocardial perfusion scintigraphy, or stress echocardiography. It can be difficult, however, to decide which technique and predictor is most effective and local practice differs. Invasive coronary angiography is not recommended unless it would be performed in the absence of surgery. Appropriate pain management should be considered in all patients and beta-blockade may improve the outcome in intermediate- and high-risk patients. Identifying patients with risk factors or previously undiagnosed coronary artery disease enables the preoperative cardiac risk assessment to guide long-term treatment. PMID:23288896

Pannell, Laura M K; Reyes, Eliana M; Underwood, S Richard



Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants.  


Objective:To characterize and investigate the relationship between systemic blood flow and pre- and postoperative cerebral electrical activity in preterm neonates undergoing patent ductus arteriosus (PDA) ligation.Study design:A prospective observational study was conducted in 17 preterm neonates undergoing PDA ligation. All infants had amplitude-integrated electroencephalography (aEEG) recorded continuously from 4?h preoperatively to 24?h postoperatively. Targeted neonatal echocardiography was performed to evaluate myocardial performance and systemic blood flow at four sequential time points: preoperatively; 1, 8 and 24?h postoperatively.Result:PDA ligation was followed by a fall in the lower border of the aEEG trace lower left ventricular output, but recovery of diastolic flow in the middle cerebral artery. Altered lower margin was associated with gestational age and PDA diameter on univariate analysis, but not with low cardiac output.Conclusion:PDA ligation was associated with altered cerebral electrical activity, although these changes were not related to low cardiac output state. PMID:23887196

Leslie, A T F S; Jain, A; El-Khuffash, A; Keyzers, M; Rogerson, S; McNamara, P J



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

PubMed Central

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

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



[High output heart failure due to an iatrogenic arteriovenous fistula after cardiac catheterization].  


The occurrence of an arteriovenous fistula is a potential complication of cardiac catheterization. Most of these fistulas cause no harm. We report the clinical case of a 70 years old woman with high-output heart failure caused by an arteriovenous fistula (FAV) in the groin. The fistula was successfully closed by surgical repair and the heart failure was resolved. This case confirms the potential harmfulness for the vascular bed of certain surgical/endovascular interventions and intravascular monitoring techniques. When heart failure of uncertain etiology appears in patients previously submitted to one of the above mentioned procedures, a careful clinical examination can lead to a correct diagnosis of iatrogenic FAV, whose surgical correction is usually followed by the restoration of a normal cardiac function. PMID:20140291

Ministro, Augusto; Costa, Tiago; Cunha e Sá, Diogo; Evangelista, Ana; da Gama, A Dinis


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

Microsoft Academic Search

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

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



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


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

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



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


We developed a multiple gas rebreathing technique for measuring lung diffusing capacity (DL(CO)), lung volume (V(L)) and cardiac output simultaneously in conscious spontaneously breathing small animals. Lung volume was measured from the dilution of methane (CH4) or sulfur hexafluoride (SF6) and verified independently by a helium washout technique. Cardiac output and DL(CO) were estimated from the uptake of acetylene and carbon monoxide, respectively. We tested guinea pigs at two levels of alveolar oxygen tension in order to estimate membrane diffusing capacity and pulmonary capillary blood volume by the Roughton-Forster technique. Results show that measured DL(CO) are consistent with reported values in anesthetized guinea pigs as well as with allometric comparison across species. Lung volume estimated from SF6 dilution agreed closely with that estimated independently from helium washout; however, lung volume estimated from CH4 dilution was systematically lower due to the addition of endogenously produced CH4 to the rebreathing system. We conclude that this technique can be used to measure resting lung function in conscious unsedated small animals. PMID:15766909

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



Correlation between supra-sternal Doppler cardiac output (USCOM) measurements and chest radiological features.  


Cardiac output can be measured non-invasively using supra-sternal Doppler (USCOM, Sydney, NSW, Australia). However, scanning can be difficult in practice in older patients, the reason for which has not been elucidated previously. Chest radiographs from 60 previously studied anaesthetised patients were reviewed and scored for aortic unfolding, enlargement and calcification, and cardiac enlargement. Corresponding supra-sternal Doppler scans were graded as easy or difficult using the Cattermole scoring system. Twenty patients who were difficult to scan, aged 60-88 years, had mean (SD) radiological scores of 5.9 (2.5) out of 12, while 20 adult controls, 40-60 years, and 20 older patients who were easy to scan, 60-80 years, had radiological scores of 0.9 (1.1) and 1.7 (1.4), respectively (p < 0.001). Over 75% of the patients who were difficult to scan had two or more radiological features suggestive of aortic unfolding and cardiac enlargement. Morphological or anatomical changes associated with ageing within the upper chest play an important part in the success of using supra-sternal Doppler in older patients. PMID:24128014

Huang, L; Critchley, L A H; Lok, R L K; Liu, Y



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



Simultaneous determination of the accuracy and precision of closed-circuit cardiac output rebreathing techniques.  


Foreign and soluble gas rebreathing methods are attractive for determining cardiac output (Q(c)) because they incur less risk than traditional invasive methods such as direct Fick and thermodilution. We compared simultaneously obtained Q(c) measurements during rest and exercise to assess the accuracy and precision of several rebreathing methods. Q(c) measurements were obtained during rest (supine and standing) and stationary cycling (submaximal and maximal) in 13 men and 1 woman (age: 24 +/- 7 yr; height: 178 +/- 5 cm; weight: 78 +/- 13 kg; Vo(2max): 45.1 +/- 9.4; mean +/- SD) using one-N(2)O, four-C(2)H(2), one-CO(2) (single-step) rebreathing technique, and two criterion methods (direct Fick and thermodilution). CO(2) rebreathing overestimated Q(c) compared with the criterion methods (supine: 8.1 +/- 2.0 vs. 6.4 +/- 1.6 and 7.2 +/- 1.2 l/min, respectively; maximal exercise: 27.0 +/- 6.0 vs. 24.0 +/- 3.9 and 23.3 +/- 3.8 l/min). C(2)H(2) and N(2)O rebreathing techniques tended to underestimate Q(c) (range: 6.6-7.3 l/min for supine rest; range: 16.0-19.1 l/min for maximal exercise). Bartlett's test indicated variance heterogeneity among the methods (P < 0.05), where CO(2) rebreathing consistently demonstrated larger variance. At rest, most means from the noninvasive techniques were +/-10% of direct Fick and thermodilution. During exercise, all methods fell outside the +/-10% range, except for CO(2) rebreathing. Thus the CO(2) rebreathing method was accurate over a wider range (rest through maximal exercise), but was less precise. We conclude that foreign gas rebreathing can provide reasonable Q(c) estimates with fewer repeat trials during resting conditions. During exercise, these methods remain precise but tend to underestimate Q(c). Single-step CO(2) rebreathing may be successfully employed over a wider range but with more measurements needed to overcome the larger variability. PMID:17556490

Jarvis, S S; Levine, B D; Prisk, G K; Shykoff, B E; Elliott, A R; Rosow, E; Blomqvist, C G; Pawelczyk, J A



Preoperative cardiac risk assessment for noncardiac surgery  

Microsoft Academic Search

Coronary artery disease (CAD) represents an important risk in patients undergoing elective noncardiac surgical procedures, in whom the stress of surgery and postoperative recovery can represent a significant ischemic burden. Population considerations: Preoperative cardiac assessment should be based on the prevalence of CAD (if known) in the population undergoing the procedure and the institutional event rate for the procedure. Procedures

Jeffrey A. Leppo



Measurement of cardiac output from a test-bolus injection in multislice computed tomography  

Microsoft Academic Search

The aim of this study was to assess the feasibility of non-invasive determination of cardiac function from test-bolus data in multislice spiral computed tomography (MSCT). In 25 patients enhancement data gathered from a standardized test-bolus injection were analyzed. The test-bolus examination was performed prior to a retrospectively ECG-gated MSCT of the heart. A time–attenuation curve was obtained in the ascending

Andreas H. Mahnken; Ernst Klotz; Anja Hennemuth; Bettina Jung; Ralf Koos; Joachim E. Wildberger; Rolf W. Günther



Cardiac assessment in the neonatal population.  


Congenital heart defects are not uncommon among neonatal patients. Although most are benign, the prompt identification of a life-threatening anomaly is essential for rapid intervention and a positive treatment outcome. Cardiac defects may be identified in the newborn nursery with thorough and systematic physical assessment, including inspection, palpation, auscultation, and measurement of blood pressure and oxygen saturations. The ability of the nurse to identify irregular findings during physical assessment aids rapid identification and treatment. PMID:20472530

Federspiel, Mary Clay


Pulmonary carbon dioxide elimination for cardiac output monitoring in peri-operative and critical care patients: history and current status.  


Minimally invasive measurement of cardiac output as a central component of advanced haemodynamic monitoring has been increasingly recognised as a potential means of improving perioperative outcomes in patients undergoing major surgery. Methods based upon pulmonary carbon dioxide elimination are among the oldest techniques in this field, with comparable accuracy and precision to other techniques. Modern adaptations of these techniques suitable for use in the perioperative and critical are environment are based on the differential Fick approach, and include the partial carbon dioxide rebreathing method. The accuracy and precision of this approach to cardiac output measurement has been shown to be similar to other minimally invasive techniques. This paper reviews the underlying principles and evolution of the method, and future directions including recent adaptations designed to deliver continuous breath-by-breath monitoring of cardiac output. PMID:23778012

Peyton, Philip J



Multiple-model adaptive predictive control of mean arterial pressure and cardiac output.  


A multiple-model adaptive predictive controller has been designed to simultaneously regulate mean arterial pressure and cardiac output in congestive heart failure subjects by adjusting the infusion rates of nitroprusside and dopamine. The algorithm is based on the multiple-model adaptive controller and utilizes model predictive controllers to provide reliable control in each model subspace. A total of 36 linear small-signal models were needed to span the entire space of anticipated responses. To reduce computation time, only the six models with the highest probabilities were used in the control calculations. The controller was evaluated on laboratory animals that were either surgically or pharmacologically altered to exhibit symptoms of congestive heart failure. During trials, the controller performance was robust with respect to excessive switching between models and nonconvergence to a single dominant model. A comparison is also made with a previous multiple-drug controller design. PMID:1505992

Yu, C; Roy, R J; Kaufman, H; Bequette, B W



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



Influence of levosimendan, pimobendan, and milrinone on the regional distribution of cardiac output in anaesthetized dogs.  

PubMed Central

1. The distribution of cardiac output during administration of levosimendan, a new myofilament calcium sensitizer, is unknown. We examined and compared the effects of levosimendan, pimobendan, and milrinone on regional tissue perfusion by use of the radioactive microsphere technique in barbiturate-anaesthetized dogs. 2. Haemodynamics and regional blood flow were determined before and during infusions of levosimendan (0.75, 1.5, and 3.0 micrograms kg-1 min-1), pimobendan (10, 20, and 40 micrograms kg-1 min-1), or milrinone (1.0, 2.0, and 4.0 micrograms kg-1 min-1). 3. All three drugs caused similar increases in heart rate, cardiac output, and left ventricular +dP/dt and decreases in end-diastolic pressure and systemic vascular resistance. No changes in subendocardial, midmyocardial, and subepicardial blood flow occurred during administration of levosimendan. However, a redistribution of blood flow from subendocardium to subepicardium was observed. Pimobendan increased midmyocardial and subepicardial blood flow and reduced the endo/epi ratio to a greater degree than levosimendan. Milrinone did not affect myocardial perfusion. 4. Levosimendan increased blood flow to the renal medulla and decreased renal medullary and cortical vascular resistance. Levosimendan increased blood flow to the small intestine and liver and reduced vascular resistance in these organs. Pimobendan increased hepatic blood flow to a greater degree than levosimendan but did not alter small intestinal perfusion. All three drugs decreased splenic blood flow to similar degrees. Levosimendan and pimobendan reduced cerebral vascular resistance. Levosimendan and milrinone reduced skeletal muscle vascular resistance. 5. The results indicate that levosimendan, pimobendan, and milrinone cause subtlety different alterations in regional tissue perfusion while producing similar haemodynamic effects.

Pagel, P. S.; Hettrick, D. A.; Warltier, D. C.



Equipment review: New techniques for cardiac output measurement - oesophageal Doppler, Fick principle using carbon dioxide, and pulse contour analysis  

PubMed Central

Measuring cardiac output is of paramount importance in the management of critically ill patients in the intensive care unit and of 'high risk' surgical patients in the operating room. Alternatives to thermodilution are now available and are gaining acceptance among practitioners who have been trained almost exclusively in the use of the pulmonary artery catheter. The present review focuses on the principles, advantages and limitations of oesophageal Doppler, Fick principle applied to carbon dioxide, and pulse contour analysis. No single method stands out or renders the others obsolete. By making cardiac output easily measurable, however, these techniques should all contribute to improvement in haemodynamic management.

Berton, Christine; Cholley, Bernard



[Scientific output: quality assessment or an accountant's tale?].  


Quality assessment of scientific output is based extensively (if not exclusively) on quantitative bibliometric indicators, despite mounting criticism. The reaction by the academic community has increased in recent years. After presenting a critical evaluation of this model, the article presents an alternative qualitative model oriented towards removing the excessive stimulus for the unbridled production of articles that make a dubious contribution to science. Criticism of the proposed model is presented and discussed. PMID:24068209

Camargo, Kenneth Rochel de



[Clinical Evaluation of Intraoperative Cardiac Output Measurement by a New Arterial Pressure Waveform Analysis Method( FloTrac/Vigileo) in Open Heart Surgery].  


We retrospectively evaluated the initial clinical experience of intraoperative cardiac output measurement by a new arterial pressure-based cardiac output (APCO:FloTrac/Vigileo) analysis in patients undergoing open heart surgery. Thirty-two patients (mean age 76.4, range 59 to 90)who underwent cardiac surgery under cardiopulmonary bypass( CPB) from July 2008 to September 2009 in our institute were enrolled in this study. There were 14 women and 18 men. The cardiac operations included 28 valve surgeries and 4 coronary artery bypass grafting. The APCO was introduced initially, then a continuous cardiac output (CCO:Swan-Ganz catheter) analysis system was established following the induction of anesthesia. The correlation of both cardiac output measurements was evaluated at 5 time points, T1:induction of anesthesia, T2:sternotomy, T3:after weaning from CPB, T4:closure of the chest, and T5:arrival at intensive care unit. There were no serious complications related to APCO and CCO. The correlation between APCO and CCO was evaluated by Bland-Altman plot analysis. The percentages of correlation between both groups were T1:81.2%, T2:78.1%, T3:59.4%, T4:62.5%, and T5:65.6%. A good correlation was shown in all 6 patients with atrial fibrillation at T1 and T2. No correlation was shown in the 3 patients with left ventricular( LV) dysfunction below LVEF 40%, 1 case at T3, all 3 cases at T4, and 2 cases at T5. Before the institution of CPB, 3 of the 6 at T1 and 3 of the 7 at T2 in whom no correlation was shown, had severe aortic valve insufficiency (AVI).From these results, APCO appears to be an acceptable device to evaluate the intraoperative cardiac output measurement compared with CCO, except in patients with LV dysfunction or AVI at some time points. Further studies will be necessary to elucidate the precise clinical evidence to assess the efficacy of this new analysis device. PMID:23917227

Furukawa, Hiroshi; Ohkado, Akihiko; Nagashima, Mitsugi; Ohsawa, Hiroshi; Ichikawa, Sei-Ichi



Enhanced cardiac thermal dilution measurement of cardiac output, volumes, regurgitation, valve effective diameters, ventricular power and efficiency -- Feasibility analysis using digital simulation.  


Cardiac output is measured by the thermal dilution method which uses a quadruple lumen catheter, with a thermistor on the tip, through the right atrium, right ventricle and into the pulmonary artery. Cold saline is injected into the right atrium and the resulting pulmonary artery temperature profile is integrated. The same procedure performed with three thermistors and three pressure sensors located on the catheter to measure temperature and pressure in the atrium, ventricle and artery respectively will produce a set of temperature and pressure curves with shapes determined by injectate temperature, injectate volume, heart rate, systolic time interval, body temperature, cardiac output, volumes, flow rates and valve openings. A digital computer program has been developed to optimize the fit of a lumped parameter model to the thermodilution curves in order to determine heart rate, systolic time as a fraction of cardiac cycle, right atrial systolic and diastolic volumes, ventricular systolic and diastolic volumes, cardiac output, inflow valve forward and reverse flow rates and effective diameters, outflow valve forward and reverse flow rates and effective diameters, ventricular power and efficiency. The program has been tested over a range of operating conditions including noise in the temperature and pressure signals, randomly varying heart rate and cardiac cycle. All of the data for the tests were produced by a digital computer simulation of a pulsatile artificial heart. The results of these tests indicate that the enhanced thermal dilution analysis method is feasible. PMID:11673669

Donovan, F M; Taylor, B C



Arterial pressure-based cardiac output in septic patients: different accuracy of pulse contour and uncalibrated pressure waveform devices  

PubMed Central

Introduction We compared the ability of two devices estimating cardiac output from arterial pressure-curve analysis to track the changes in cardiac output measured with transpulmonary thermodilution induced by volume expansion and norepinephrine in sepsis patients. Methods In 80 patients with septic circulatory failure, we administered volume expansion (40 patients) or introduced/increased norepinephrine (40 patients). We measured the pulse contour-derived cardiac index (CI) provided by the PiCCO device (CIpc), the arterial pressure waveform-derived CI provided by the Vigileo device (CIpw), and the transpulmonary thermodilution CI (CItd) before and after therapeutic interventions. Results The changes in CIpc accurately tracked the changes in CItd induced by volume expansion (bias, -0.20 ± 0.63 L/min/m2) as well as by norepinephrine (bias, -0.05 ± 0.74 L/min/m2). The changes in CIpc accurately detected an increase in CItd ? 15% induced by volume expansion and norepinephrine introduction/increase (area under ROC curves, 0.878 (0.736 to 0.960) and 0.924 (0.795 to 0.983), respectively; P < 0.05 versus 0.500 for both). The changes in CIpw were less reliable for tracking the volume-induced changes in CItd (bias, -0.23 ± 0.95 L/min/m2) and norepinephrine-induced changes in CItd (bias, -0.01 ± 1.75 L/min/m2). The changes in CIpw were unable to detect an increase in CItd ? 15% induced by volume expansion and norepinephrine introduction/increase (area under ROC curves, 0.564 (0.398 to 0.720) and 0.541 (0.377 to 0.700, respectively, both not significantly different from versus 0.500). Conclusions The CIpc was reliable and accurate for assessing the CI changes induced by volume expansion and norepinephrine. By contrast, the CIpw poorly tracked the trends in CI induced by those therapeutic interventions.



Non-invasive determination of stroke volume and cardiac output after high intensity playing exercise in elite female soccer players  

Microsoft Academic Search

BackgroundStroke volume (SV) and heart rate (HR), determining cardiac output (CO), are crucial hemodynamic parameters determining training adoptions to endurance training. In soccer, aerobic power as well as intermittent exercise performance varies significantly among level of competition as well as playing position. In this study cohort study we thought to determine the hemodynamic changes following a standardized soccer-specific exercise in

Karsten Knobloch



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



Interrelationship between cardiac output and vascular resistance as determinants of effective arterial blood volume in cirrhotic patients  

Microsoft Academic Search

Interrelationship between cardiac output and vascular resistance as determinants of effective arterial blood volume in cirrhotic patients. The effect of head-out water immersion (HWI) in decompensated cirrhotic patients to correct sodium and water excretion has been found to be incomplete and variable. The explanation may be that the efficacy of HWI in correcting a decreased effective arterial blood volume (EABV)

Michael D Shapiro; Kathleen M Nicholls; Bertron M Groves; Rudiger Kluge; Hsaio-Min Chung; Daniel G Bichet; Robert W Schrier



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

Microsoft Academic Search

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

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



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

PubMed Central

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

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



The Effects of Spread of Block and Adrenaline on Cardiac Output After Epidural Anesthesia in Young Children: A Randomized, Double-Blind, Prospective Study  

Microsoft Academic Search

Epidural anesthesia is considered to be without signifi- cant hemodynamic consequence in young children. However, conversely to adults, few studies have inves- tigated cardiac output. Using transesophageal Doppler monitoring of cardiac output, we prospectively investi- gated hemodynamic alterations in 48 children (median age, 22.5 mo) receiving sevoflurane general anesthesia combined with caudal or thoracolumbar epidural anes- thesia. They were randomly

Olivier Raux; Alain Rochette; Estelle Morau; Christophe Dadure; Christine Vergnes; Xavier Capdevila



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



Effects of velocity distribution, diameter measurement and velocity tracing on the accuracy of cardiac output measurement by pulsed doppler echocardiography in the aortic annulus of pigs  

Microsoft Academic Search

The accuracy of cardiac output measurement by pulsed Doppler echocardiography can be affected by several factors, such as the velocity distribution, the measurement of diameter and the method of tracing the pulsed Doppler flow spectrum. This experimental study was designed to find the most accurate way of measuring cardiac output in consideration of all these factors. In 10 open-chest normal

Yu-Qing Zhou; Svein Faerestrand; Sigurd Birkeland; Knut Matre; Paul Husby; Mai-Elin Koller



Noninvasive measurement of cardiac output in hemodialysis patients by task force monitor: a comparison with the Transonic System.  


Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysis (MHD) patients. The Transonic (TRS; Transonic Systems, Ithaca, NY) device is frequently used for determination of cardiac output (CO) by an indicator dilution technique. The Task Force Monitor (TFM; CN Systems, Graz, Austria) has gained attention as noninvasive tool for continuous beat-to-beat assessment of cardiovascular variables, including CO by impedance cardiography. Despite its use in cardiology and intensive care settings, the TFM has yet not been validated in dialysis patients. This study compares CO measurements in 12 MHD patients by TFM and TRS. Bland-Altman and regression analysis were used. CO was measured simultaneously by TRS and TFM. Average CO was 5.4 L/min by TRS and 5.0 L/min by TFM, respectively. Bland-Altman analysis revealed no significant systematic differences between the two methods (mean difference: 0.4 L/min; SD: 0.6; p > 0.05). Linear regression analysis showed significant correlation between both techniques (r = 0.802, p = 0.002). The SD of mean individual CO values was 1.1 L/min with TRS and 0.8 L/min with TFM, respectively.CO measured by TFM and TRS does not differ significantly, thus making the TFM an attractive noninvasive tool for the continuous beat-to-beat assessment of CO in MHD patients. PMID:17885328

Kitzler, Thomas M; Sergeyeva, Olga; Morris, Alice; Skrabal, Falko; Kotanko, Peter; Levin, Nathan W


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.

Fazeli, Nima; Hahn, Jin-Oh



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


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

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



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

PubMed Central

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 the management of patients. Indeed, the interchangeability of the methods is a clinically relevant question; for instance, in view of the debate about the risk–benefit balance of right heart catheterization. Patients and methods Eighteen mechanically ventilated passive patients with a right heart catheter in place were studied (six women, 12 men; age, 39–84 years; simplified acute physiology scoreII, 39–111). QTTHERM was obtained using a standard procedure. QTFICK was measured from oxygen consumption, carbon dioxide production, and arterial and mixed venous oxygen contents. Forty-nine steady-state pairs of measurements were performed. The data were normalized for repeated measurements, and were tested for correlation and agreement. Results The QTFICK value was 5.2 ± 2.0 l/min whereas that of QTTHERM was 5.8 ± 1.9 l/min (R = 0.840, P < 0.0001; mean difference, -0.7 l/min; lower limit of agreement, -2.8 l/min; upper limit of agreement, 1.5 l/min). The agreement was excellent between the two techniques at QTTHERM values <5 l/min but became too loose for clinical interchangeability above this value. Tricuspid regurgitation did not influence the results. Discussion and conclusions No gold standard is established to measure cardiac output in critically ill patients. The thermodilution method has known limitations that can lead to inaccuracies. The metabolic method also has potential pitfalls in this context, particularly if there is increased oxygen consumption within the lungs. The concordance between the two methods for low cardiac output values suggests that they can both be relied upon for clinical decision making in this context. Conversely, a high cardiac output value is more difficult to rely on in absolute terms.

Gonzalez, Jesus; Delafosse, Christian; Fartoukh, Muriel; Capderou, Andre; Straus, Christian; Zelter, Marc; Derenne, Jean-Philippe; Similowski, Thomas



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

Microsoft Academic Search

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

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



Assessment of Diastolic Function by Cardiac MRI  

Microsoft Academic Search

Cardiac magnetic resonance imaging (MRI) techniques continue to change rapidly, and cardiac MRI is developing as an alternative\\u000a noninvasive technique having the unique potential of three-dimensional function analysis with great accuracy and reproducibility.\\u000a Advances in rapid cardiac MRI technology are making real-time imaging possible at approaching echocardiographic frame rates.\\u000a Together with the increasing availability of cardiac MRI machines, cardiac MRI

Bernard P. Paelinck; Hildo J. Lamb


Evaluation of a noninvasive continuous cardiac output monitoring system based on thoracic bioreactance.  


Noninvasive cardiac output (CO) measurement can be useful in many clinical settings where invasive monitoring is not desired. Bioimpedance (intrabeat measurement of changes in transthoracic voltage amplitude in response to an injected high-frequency current) has been explored for this purpose but is limited in some clinical settings because of inherently low signal-to-noise ratio. Since changes in fluid content also induce changes in thoracic capacitive and inductive properties, we tested whether a noninvasive CO measurement could be obtained through measurement of the relative phase shift of an injected current (i.e., bioreactance). We constructed a prototype device that applies a 75-kHz current and determines the relative phase shift (dPhi/dt) of the recorded transthoracic voltage. CO was related to the product of peak dPhi/dt, heart rate, and ventricular ejection time. The preclinical study was done in nine open-chest pigs put on right heart bypass so that CO could be varied at known values. This was followed by a feasibility study in 27 postoperative patients who had a Swan-Ganz catheter (SGC). The measurements of noninvasive CO measurement and cardiopulmonary bypass pump correlated to each other (r = 0.84) despite the large variation in CO and temperatures. Similarly, in patients, mean CO values were 5.18 and 5.17 l/min as measured by SGC and the noninvasive CO measurement system, respectively, and were highly correlated over the range of values studied (r = 0.90). Preclinical and clinical data demonstrate the feasibility of using blood flow-related phase shifts of transthoracic electric signals to perform noninvasive continuous CO monitoring. PMID:17384132

Keren, Hanan; Burkhoff, Daniel; Squara, Pierre



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.



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


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

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



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

PubMed Central

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

Yoshida, T; Whipp, B J



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

PubMed Central

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

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



Control of right atrial pressure at constant cardiac output suppresses volume natriuresis in anesthetized rats.  


The blood volume of anesthetized rats was expanded acutely by 33% with donor blood while a caval snare was gradually tightened so that right atrial pressure (RAP) was prevented from rising (n = 6). In control experiments (n = 5) an aortic snare was used to hold mean arterial blood pressure near the values found in the experimental series. However, RAP was allowed to change freely and increased by 1.6 +/- 0.4 mmHg (1 mmHg = 133.322 Pa) during volume expansion. When the two groups were compared, there were no significant differences between their mean arterial blood pressures (near 110 mmHg) or in their cardiac outputs (near 0.25 mL X min-1 X g body weight-1). There were, however, significant differences between their renal responses to the volume load. When RAP was free to change, the rate of volume excretion (V) increased to 30 +/- 15 (SEM) microL X min-1 X g kidney weight-1 (KW) from its control value of 3.49 +/- 0.31 and the rate of sodium excretion (UNaV) increased to 3.59 +/- 0.20 muequiv X min-1 X g KW-1 from its preinfusion value of 0.42 +/- 0.10. When RAP was not allowed to increase during volume loading, V and UNaV did not change from their respective preinfusion values (2.99 +/- 0.46 microL X min-1 X g KW-1 and 0.35 +/- 0.10 muequiv X min-1 X g KW-1). The results imply that during acute blood volume expansion increased central vascular pressure is a prerequisite for the homeostasis of body water and salt. PMID:6498610

Ackermann, U; Rudolph, J R



Clinical validation of cardiac output measurements using femoral artery thermodilution with direct Fick in ventilated children and infants  

Microsoft Academic Search

Objective: To validate clinically cardiac output (CO) measurements using femoral artery thermodilution in ventilated children and infants\\u000a by comparison with CO estimated from the Fick equation via a metabolic monitor. Design: Prospective, comparison study. Setting: Paediatric intensive care unit of a university hospital. Patients: 24 ventilated infants and children, aged 0.3 to 175 months (median age 19 months). Interventions: Oxygen

S. M. Tibby; M. Hatherill; M. J. Marsh; G. Morrison; D. Anderson; I. A. Murdoch



The use of the electrical-impedance technique for the monitoring of cardiac output and limb bloodflow during anaesthesia  

Microsoft Academic Search

A need has long existed during routine anaesthesia for a convenient, noninvasive method for the monitoring of stroke volume,\\u000a and hence of changes in cardiac output. If knowledge of the mean arterial blood pressure is available, it becomes possible\\u000a to monitor changes occurring in the left-ventricular stroke work and the total systemic resistance. Nyboer et al. (1940) proposed\\u000a the use

D. W. Hill; H. J. Lowe



Cardiac output measurement by transpulmonary versus conventional thermodilution technique in intensive care patients after coronary artery bypass grafting  

Microsoft Academic Search

Objective: The aim of the present study was to evaluate the correlation, accuracy, and precision of transpulmonary thermodilution cardiac output (CO) measurement. For this purpose, this technique was compared with the clinical gold standard, the CO measurement by pulmonary artery catheter in patients after coronary artery bypass grafting (CABG).Design: A prospective clinical study.Setting: A university medical center.Participants: Seventy-five patients in

René Gust; André Gottschalk; Harald Bauer; Bernd W. Böttiger; Hubert Böhrer; Eike Martin



Development and in vitro validation of a device for measuring non-shunt cardiac output by nitrous oxide throughflow  

Microsoft Academic Search

A system has been developed for measuring non-shunt cardiac output by the throughflow technique, using nitrous oxide in patients\\u000a undergoing general anaesthesia. The throughflow measurement technique is a non-invasive method based on inert gas throughflow\\u000a theory. In vitro validation of the measurement system was performed using a lung gas exchange simulator. The accuracy and\\u000a precision of the throughflow measurement system

G. M. Vartuli; R. B. Burfoot; G. J. B. Robinson; P. J. Peyton; P. A. Junor



Cardiac Output, Renal Blood Flow and Hepatic Blood Flow in Rats with Glycerol-Induced Acute Renal Failure  

Microsoft Academic Search

Cardiac output (CO), renal blood flow (RBF) and hepatic blood flow (HBF) were measured by the microsphere method before (control) and at 4 and 10 h after the induction of acute renal failure by intramuscular injection of glycerol in water-drinking, long-term saline-drinking and long-term captopril (converting enzyme inhibitor)-drinking rats. At 4 h after glycerol injection, CO, RBF and HBF significantly

T. Kishimoto; W. Sakamoto; T. Nakatani; T. Ito; K. Iwai; T. Kim; Y. Abe



Effects of Endothelin1 and Endothelin1 Receptor Blockade on Cardiac Output, Aortic Pressure, and Pulse Wave Velocity in Humans  

Microsoft Academic Search

Endothelin-1 (ET-1) is a potent vasoconstrictor. Its effect on arterial wave reflections and central pressure augmentation is unknown. We studied whether ET-1, in plasma concentrations present in disease, increases pulse wave velocity (PWV) and augmentation index (AIx) and therefore compromises cardiac output, and whether the ET-1 receptor blocker VML-588 (previously AXV-034343 and Ro 61-1790) prevents such effects. Nine healthy men

Tycho J. L. Vuurmans; Peter Boer; Hein A. Koomans


[Reliability of a less-invasive cardiac output monitor in the perioperative period of a patient with severe dilated cardiomyopathy].  


Recently, various less-invasive cardiac output monitors are used for a variety of cases. We used FloTrac system for a patient with severe dilated cardiomyopathy (LVDd/Ds = 75/62 mm, EF = 22%) and recognized its limitation. A 52-year-old woman underwent left partial mastectomy. There were no significant events during the operation. In the ICU, she developed symptoms of low output state, but we could not detect any significant changes on Vigileo Monitor. Arterial pressure-based cardiac output (APCO) measurement with FloTrac is based on the patient's characteristics, blood pressure waveform and basic data stored in Vigileo Monitor. Its accuracy is worse with arterial wave artifact, compromise of the arterial catheter, aortic regurgitation, intense peripheral vasoconstriction, irregular pulse and severe cardiac hypofunction. Thus, its reliability is influenced by various conditions, especially in critically ill patients. FloTrac system is very useful for the management of cardiocirculatory dynamics, but we should be familiar with its limitations. PMID:21384657

Sotomi, Yohei; Nishiyama, Chie; Shimizu, Tomoaki; Kita, Takashi; Maki, Naritoshi; Sasaki, Shigeta



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

PubMed Central

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

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



The methodology of quantitative assess economic output of climate change  

Microsoft Academic Search

A method is introduced in this paper to study the effect of future climatic change on the economy. The researchers determine\\u000a the economic output of climate change from historical data, and provide a method to quantitatively predict economic output\\u000a of climate change by an economic-climatic model. A historical reciprocating examination is used to analyze output data for\\u000a various crops in

JieMing Chou; WenJie Dong; GuoLin Feng



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


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

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



Pharmacologic Interventions in Nuclear Medicine Assessment of Cardiac Perfusion  

Microsoft Academic Search

Drugs that are currently used for therapeutic purposes can also be used in diagnostic tests. This paper will review the use of such pharmacological interventions in cardiac assessment in Nuclear Medicine. To fully com- prehend the effect of these drugs, a small review of diag- nostic nuclear medicine as currently used to assess cardiac perfusion is included. This will allow

Gilbert G. Matte; David C. Barnes; Douglas N. Abrams



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



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

PubMed Central

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

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



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


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



Cardiac Assessment in Duchenne and Becker Muscular Dystrophies  

Microsoft Academic Search

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

Tae-Jin Song; Young-Chul Choi


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

PubMed Central

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 the reduction in skeletal muscle blood flow is not directly proportional to the reduction in cardiac output and that there are regional differences in blood flow in patients with heart failure. METHODS--Cardiac output and regional blood flow measured in 30 patients with chronic heart failure were compared with values obtained from 10 healthy controls. Measurements were made at rest and in response to treadmill exercise and were all made non-invasively. RESULTS--Cardiac output was lower in the patients at rest and during exercise. Blood flow in the superior mesenteric and renal arteries was also lower in the patients and represented a different proportion of cardiac output than in the controls. In response to exercise the increase in blood flow to the calf and therefore to skeletal muscle, was reduced in the patients. In the patients there was no correlation between resting cardiac output and blood flow in the superior mesenteric artery, renal artery, or calf. CONCLUSIONS--Because blood flow to skeletal muscle and to the kidneys is likely to be important in determining patients' symptoms this factor may explain why central haemodynamic variables do not correlate with the exercise tolerance in patients with chronic heart failure.

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



[Applicability of the two-compartment coaxial cylindrical model for ambulatory measuring of cardiac output with spot-electrodes].  


The principle of ambulatory cardiac output (CO) measuring technique is introduced in this paper. Experimental studies about the applicability of the two-compartment coaxial cylindrical model for ambulatory measurement of cardiac output with spot-electrodes have been carried out with using our newly-developed multi-channel impedance mapping system. The key factors using a spot-electrode array instead of a conventional band-electrode array for non-invasive CO) measurement are elaborated. The variations of the electric impedance pulsatile component (deltaZ waveform) and the two kinds of typical modes of deltaZ distributions measured by six electrodes on the midsternal (midian) line from the medial portion at the level of clavicle to the portion above the xiphisternum are discussed. The applicability of the two-compartment coaxial cylindrical model for ambulatory measurement of CO with spot-electrodes is analyzed. Synthesizing the deltaZ distributions and their typical changing models on the midsternal (midian) line during blood inflowing into aorta is the optimal positions of a pair of spot-electrodes for voltage pick-up at the level of clavicle for the upper electrode and the position at the level of nipple for the lower electrode when spot-electrode is being used to measure non-invasive CO. PMID:24059037

Song, Yilin; Gao, Shumei; Ikrashi, Akira; Yamakoshi, Ken-ichi



Scintigraphic assessment of heterotopic cardiac transplants  

SciTech Connect

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

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



Scintigraphic assessment of heterotopic cardiac transplants  

SciTech Connect

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

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



Numerical observer for cardiac motion assessment using machine learning  

NASA Astrophysics Data System (ADS)

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

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



Self-calibrating pulse contour cardiac output: do validation studies really show its clinical reliability?  

Microsoft Academic Search

The present study was performed to test a new software version of the FloTrac\\/Vigileo using head-up–head-down tilting in post-cardiac\\u000a surgery patients. Impressive improvements in Bland and Altman limits of agreement from 37.5% to 21.6% were recorded. The results,\\u000a however could be attributed to a failure to produce a wide enough range of test circulatory conditions. A more rigorous test\\u000a of

Lester AH Critchley; Intensive Care



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

PubMed Central

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

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



Interactive Visualization for Rapid Noninvasive Cardiac Assessment  

Microsoft Academic Search

New interactive computerized visualization technology promises to give doctors easier, quicker and less expensive ways to determine whether and to what extent patients have heart disease. This new visualization technology, combined with new image acquisition methods, may allow doctors to take the results of one noninvasive cardiac examination and produce a variety of 3D displays that can be easily manipulated

Meiyappan Solaiyappan; Tim Poston; Pheng-ann Heng; Elliot R. Mcveigh; Michael A. Guttman; Elias A. Zerhouni



Assessment of calcium scoring performance in cardiac computed tomography  

Microsoft Academic Search

  \\u000a Electron beam tomography (EBT) has been used for cardiac diagnosis and the quantitative assessment of coronary calcium since\\u000a the late 1980s. The introduction of mechanical multi-slice spiral CT (MSCT) scanners with shorter rotation times opened new\\u000a possibilities of cardiac imaging with conventional CT scanners. The purpose of this work was to qualitatively and quantitatively\\u000a evaluate the performance for EBT

Stefan Ulzheimer; Willi A. Kalender



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


The Type D personality, identified by high negative affectivity paired with high social inhibition, has been associated with a number of health-related outcomes in (mainly) cardiac populations. However, despite its prevalence in the health-related literature, how this personality construct fits within existing personality theory has not been directly tested. Using a sample of 134 healthy university students, this study examined the Type D personality in terms of two well-established personality traits; introversion and neuroticism. Construct, concurrent and discriminant validity of this personality type was established through examination of the associations between the Type D personality and psychometrically assessed anxiety, depression and stress, as well as measurement of resting cardiovascular function. Results showed that while the Type D personality was easily represented using alternative measures of both introversion and neuroticism, associations with anxiety, depression and stress were mainly accounted for by neuroticism. Conversely, however, associations with resting cardiac output were attributable to the negative affectivity-social inhibition synergy, explicit within the Type D construct. Consequently, both the construct and concurrent validity of this personality type were confirmed, with discriminant validity evident on examination of physiological indices of well-being. PMID:21809947

Howard, Siobhán; Hughes, Brian M



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

PubMed Central

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



Variations in arterial blood pressure are associated with parallel changes in FlowTrac/Vigileo®-derived cardiac output measurements: a prospective comparison study  

PubMed Central

Introduction The reliability of autocalibrated pressure waveform analysis by the FloTrac-Vigileo® (FTV) system for the determination of cardiac output in comparison with intermittent pulmonary arterial thermodilution (IPATD) is controversial. The present prospective comparison study was designed to determine the effects of variations in arterial blood pressure on the reliability of the FTV system in patients undergoing coronary artery bypass grafting (CABG). Methods Comparative measurements of cardiac output by FTV (derived from a femoral arterial line; software version 1.14) and IPATD were performed in 16 patients undergoing elective CABG in the period before institution of cardiopulmonary bypass. Measurements were performed after induction of anesthesia, after sternotomy, and during five time points during graft preparation. During graft preparation, arterial blood pressure was increased stepwise in intervals of 10 to 15 minutes by infusion of noradrenaline and lowered thereafter to baseline levels. Results Mean arterial blood pressure was varied between 85 mmHg and 115 mmHg. IPATD cardiac output did not show significant changes during periods with increased arterial pressure either during sternotomy or after pharmacological manipulation. In contrast, FTV cardiac output paralleled changes in arterial blood pressure; i.e. increased significantly if blood pressure was raised and decreased upon return to baseline levels. Mean arterial blood pressure (MAP) and FTV cardiac output were closely correlated (r = 0.63 (95% confidence interval [CI]: 0.49 - 0.74), P < 0.0001) while no correlation between MAP and IPATD cardiac output was observed. Bland-Altman analyses for FTV versus IPATD cardiac output measurements revealed a bias of 0.4 l/min (8.5%) and limits of agreement from 2.1 to -1.3 l/min (42.2 to -25.3%). Conclusions Acute variations in arterial blood pressure alter the reliability of the FlowTrac/Vigileo® device with the second-generation software. This finding may help to explain the variable results of studies comparing the FTV system with other cardiac output monitoring techniques, questions the usefulness of this device for hemodynamic monitoring of patients undergoing rapid changes in arterial blood pressure, and should be kept in mind when using vasopressors during FTV-guided hemodynamic optimization.



[Clinical practice guide for the management of low cardiac output syndrome in the postoperative period of heart surgery].  


The low cardiac output syndrome is a potential complication in cardiac surgery patients and associated with increased morbidity and mortality. This guide is to provide recommendations for the management of these patients, immediately after surgery, admitted to the ICU. The recommendations are grouped into different sections, trying to answer from the most basic concepts such as the definition to the different sections of basic and advanced monitoring and ending with the complex management of this syndrome. We propose an algorithm for initial management, as well as two other for ventricular failure (predominantly left or right). Most of the recommendations are based on expert consensus because of the lack of randomized trials of adequate design and sample size in this group of patients. The quality of evidence and strength of the recommendations were made following the GRADE methodology. The guide is presented as a list of recommendations (and level of evidence for each recommendation) for each question on the selected topic. Then for each question, we proceed to the justification of the recommendations. PMID:22445905

Pérez Vela, J L; Martín Benítez, J C; Carrasco González, M; de la Cal López, M A; Hinojosa Pérez, R; Sagredo Meneses, V; del Nogal Saez, F



Objective assessment of technical skills in cardiac surgery  

Microsoft Academic Search

Objective: Reduced training time combined with no rigorous assessment for technical skills makes it difficult for trainees to monitor their competence. We have developed an objective bench-top assessment of technical skills at a level commensurate with a junior registrar in cardiac surgery. Methods: Forty cardiothoracic surgeons were recruited for the study, consisting of 12 junior trainees (year 1–3), 15 senior

Julian Hance; Rajesh Aggarwal; Rex Stanbridge; Christopher Blauth; Yaron Munz; Ara Darzi; John Pepper



Output products of the Federal Radiological Monitoring and Assessment Center  

Microsoft Academic Search

The Federal Radiological Emergency Response Plan (FRERP) mandates that the U.S. Department of Energy (DOE) establish a Federal Radiological Monitoring and Assessment Center (FRMAC) when a major radiological emergency occurs. The Nevada Operations Office (DOE\\/NV) has played a key role in developing the FRMAC concept. This paper explains the center's concept, summarizes the specific tasks of the FRMAC, and describes




Comparison of ergonomic risk assessment output in four sawmill jobs.  


The objectives of this study were to examine the agreement between 5 ergonomic risk assessment methods calculated on the basis of quantitative exposure measures and to examine the ability of the methods to correctly classify 4 at risk jobs. Surface electromyography and electrogoniometry were used to record the physical exposures of 87 sawmill workers performing 4 repetitive jobs. Five ergonomic risk assessment tools (rapid upper limb assessment [RULA], rapid entire body assessment [REBA], American conference of governmental industrial hygienist's threshold limit value for mono-task hand work [ACGIH TLV], strain index [SI], and concise exposure index [OCRA]) were calculated. Dichotomization of risk to no risk and at risk resulted in high agreement between methods. Percentage of perfect agreement between methods when 3 levels of risk were considered was moderate and varied by job. Of the methods examined, the RULA and SI were best (correct classification rates of 99 and 97% respectively). The quantitative ACGIH-TLV for mono-task hand work and Borg scale were worst (misclassification rates of 86 and 28% respectively). PMID:20331923

Jones, Troy; Kumar, Shrawan



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

PubMed Central

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

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



Cardiac output monitoring in septic shock: evaluation of the third-generation Flotrac-Vigileo.  


Continuous cardiac index (CI) monitoring is frequently used in critically ill patients. Few studies have compared the pulse contour-based device FloTrac/Vigileo to pulmonary artery thermodilution (PAC) in terms of accuracy for CI monitoring in septic shock. The aim of our study was to compare the third-generation FloTrac/Vigileo to PAC in septic shock. Eighteen patients with septic shock requiring monitoring by PAC were included in this study. We monitored CI using both FloTrac/Vigileo and continuous thermodilution (PAC-CI). Hemodynamic data were recorded every hour or every 2 min during fluid challenges. The primary endpoint was the global agreement of all CI-paired measurements determined using the Bland-Altman method adapted to replicated data. We tested the linearity of the bias by regression analysis, and compared the reactivity of the 2 techniques during fluid challenges. A receiver operating characteristic (ROC) curve analysis tested the ability of FloTrac/Vigileo to detect concordant and significative CI changes, using PAC-CI as the reference method. Overall, 1,201 paired CI measurements were recorded. The Bland-Altman analysis for global agreement of the 2 techniques showed a bias of -0.1 ± 2.1 L min(-1) m(-2) and a percentage error of 64 %. The overall correlation coefficient between PAC-CI and FloTrac/Vigileo CI was 0.47 (p < 0.01), with r(2) = 0.22. The area under the curve of the ROC curve for detecting concordant and significant changes in CI was 0.72 (0.53; 0.87). In our study, third-generation Flowtrac-Vigileo appears to be too inaccurate to be recommended for CI monitoring in septic shock. PMID:23361128

Marqué, Sophie; Gros, Antoine; Chimot, Loic; Gacouin, Arnaud; Lavoué, Sylvain; Camus, Christophe; Le Tulzo, Yves



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))



Clinical assessment of cardiac performance in infants and children following cardiac  

Microsoft Academic Search

Objective: To compare clinical assessment of cardiac per- formance with an invasive method of haemodynamic monitoring. Design and setting: Prospective observa- tional study in a 16-bed tertiary pae- diatric intensive care unit. Patients and participants: Infants and children undergoing cardiopulmonary bypass and surgical repair of congenital heart lesions. Interventions: Based on physical examination and routinely available haemodynamic monitoring in the

Jonathan R. Egan; Marino Festa; Andrew D. Cole; Graham R. Nunn; Jonathan Gillis; David S. Winlaw



Clinical assessment of cardiac performance in infants and children following cardiac surgery  

Microsoft Academic Search

Objective: To compare clinical assessment of cardiac per- formance with an invasive method of haemodynamic monitoring. Design and setting: Prospective observa- tional study in a 16-bed tertiary pae- diatric intensive care unit. Patients and participants: Infants and children undergoing cardiopulmonary bypass and surgical repair of congenital heart lesions. Interventions: Based on physical examination and routinely available haemodynamic monitoring in the

Jonathan R. Egan; Marino Festa; Andrew D. Cole; Graham R. Nunn; Jonathan Gillis; David S. Winlaw



Comparison of impedance cardiography with thermodilution and direct fick methods for noninvasive measurement of stroke volume and cardiac output during incremental exercise in patients with ischemic cardiomyopathy  

Microsoft Academic Search

In the last decade, an inexpensive and simple noninvasive method (i.e., transthoracic electrical bioimpedance cardiography, has been tested in healthy subjects and patients with various heart diseases for measuring stroke volume and cardiac output at rest and\\/or during exercise. However, the results are still controversial, especially when measurements are obtained during exercise and data on reproducibility during exercise are lacking.

Romualdo Belardinelli; Nino Ciampani; Carlo Costantini; Alfonso Blandini; Augusto Purcaro



Acute effects of muscular counterpulsation therapy on cardiac output and safety in patients with chronic heart failure.  


Our aim was to investigate acute effects of muscular counterpulsation (MCP) on hemodynamic parameters and to evaluate its safety in regard to myocardial integrity and interferences with implanted rhythm devices in patients with chronic heart failure (CHF). A total of 22 patients with CHF (16 male, 67.8?±?9.5 years, New York Heart Association [NYHA] class II?+?III, left ventricular ejection fraction 29.6?±?6.6%) were treated with MCP for 3 consecutive days for 45?min, while hemodynamic parameters were measured noninvasively by bioimpedance (Task Force Monitor). Laboratory control and a complete device testing were performed prior to the first and after the third treatment. In addition, continuous rhythm device interrogation was performed online during the first MCP application. During each application, a significant increase in cardiac output (CO; average change +2.08?±?2.33?L/min, P?Cardiac markers and enzymes were within normal limits at all times and did not increase during treatment. MCP stimuli were monitored using surface electrocardiogram, and no abnormal sensing or pacing events occurred. MCP acutely improves CO in patients with stable CHF. No adverse influence on myocardial integrity was observed nor were any inappropriate sensing or pacing artifacts detected in patients with implanted rhythm devices. PMID:22145938

Ostojic, Dominique; Seifert, Ingmar; Pütz, Vanessa; Bartsch, Stephan; Bitter, Thomas; Horstkotte, Dieter; Oldenburg, Olaf



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

PubMed Central

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



Computer-aided assessment of cardiac computed tomographic images  

NASA Astrophysics Data System (ADS)

The accurate interpretation of cardiac CT images is commonly hindered by the presence of motion artifacts. Since motion artifacts commonly can obscure the presence of coronary lesions, physicians must spend much effort analyzing images at multiple cardiac phases in order to determine which coronary structures are assessable for potential lesions. In this study, an artificial neural network (ANN) classifier was designed to assign assessability indices to calcified plaques in individual region-of-interest (ROI) images reconstructed at multiple cardiac phases from two cardiac scans obtained at heart rates of 66 bpm and 90 bpm. Six individual features (volume, circularity, mean intensity, margin gradient, velocity, and acceleration) were used for analyzing images. Visually-assigned assessability indices were used as a continuous truth, and jack-knife analysis with four testing sets was used to evaluate the performance of the ANN classifier. In a study in which all six features were inputted into the ANN classifier, correlation coefficients of 0.962 +/- 0.006 and 0.935 +/- 0.023 between true and ANN-assigned assessability indices were obtained for databases corresponding to 66 bpm and 90 bpm, respectively.

King, Martin; Giger, Maryellen; Suzuki, Kenji; Pan, Xiaochuan



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 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.



Assessment of fetal cardiac function in mild preeclampsia.  


This study investigated cardiac function in 65 fetuses of mildly preeclamptic mothers and 55 fetuses of healthy mothers at 26-40 weeks of gestation. Fetuses with intrauterine growth restriction were excluded. Cardiac functions were evaluated by M-mode, pulsed-wave, and tissue Doppler echocardiography. The two groups were similar in terms of maternal age, gravidity, parity, and gestational age. Peak systolic aortic and pulmonary artery velocities were significantly lower in the fetuses of the preeclamptic mothers than in the fetuses of the healthy mothers. The two groups did not differ significantly in terms of shortening fraction or with regard to mitral or tricuspid annular plane systolic excursion. Pulsed-wave Doppler-derived E/A ratios in the mitral and tricuspid valves were similar in the two groups. The deceleration time of early mitral inflow was prolonged in the fetuses of the preeclamptic mothers. The Ea, Aa, and Ea/Aa ratios in the interventricular septum, left ventricle posterior wall, and right ventricle free wall were lower in the preeclampsia group than in the control group. The E/Ea ratio was higher in the preeclampsia group than in the control group. The isovolumic relaxation time and the right and left myocardial performance indices were higher in the fetuses of the preeclamptic mothers than in the fetuses of the healthy mothers. An increased ductus venosus pulsatility index (PI) and a decreased middle cerebral artery (MCA) PI were found in the fetuses of the preeclamptic mothers. All the fetuses were asymptomatic. The results suggest that the increase in fetal cardiac afterload in mild preeclampsia may have caused early subclinical changes in fetal systolic and diastolic cardiac function. In addition, the decrease in MCA-PI may have been caused by redistribution of fetal cardiac output in favor of the left ventricle, secondary to increased placental vascular resistance. PMID:23591803

Balli, Sevket; Kibar, Ayse Esin; Ece, Ibrahim; Oflaz, Mehmet Burhan; Yilmaz, Ozcan



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

SciTech Connect

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

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



Nimodipine has no effect on the cerebral circulation in conscious pigs, despite an increase in cardiac output.  

PubMed Central

1. We studied the effects of four doses of nimodipine (0.5, 1, 2 and 4 micrograms kg-1 min-1) on systemic haemodynamics and on regional vascular beds, in particular the cerebral circulation, in conscious pigs. 2. Nimodipine caused dose-dependent, probably reflex-mediated, increases in heart rate (42% with the highest dose) and cardiac output (54%), while arterial blood pressure was only minimally affected. Left ventricular end-diastolic pressure and systemic vascular resistance decreased dose-dependently (35-40% at the highest dose) while stroke volume remained unchanged. 3. Total brain blood flow was not affected by the drug. Furthermore, we could not demonstrate any regional cerebral differences, as blood flows to both cerebral hemispheres as well as the diencephalon, cerebellum and brain stem remained unchanged. 4. Blood flow to the kidneys, liver, small intestine and skin also did not change. Nimodipine caused dose-dependent increases in blood flow to the stomach (95%), myocardium (97%) and adrenal glands (102%), while blood flow to skeletal muscles (267%) increased most. 5. It is concluded that in the conscious pig, nimodipine is an arterial vasodilator which shows some selectivity for the skeletal muscle vasculature but does not increase total or regional cerebral blood flow.

van der Giessen, W. J.; Duncker, D. J.; Saxena, P. R.; Verdouw, P. D.



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


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; O'Leary, Donal S



Crystalloid and colloid preload for maintaining cardiac output in elderly patients undergoing total hip replacement under spinal anesthesia  

PubMed Central

The aim of the present study was to compare the effects of colloid and crystalloid preload on cardiac output (CO) and incidence of hypotension in elderly patients under spinal anesthesia (SA). A randomized, double-blinded study was conducted including 47 elderly patients undergoing scheduled total hip replacement (THR), who were randomized to three groups: the control group (C group, n = 15), crystalloid (RS group, n =16) and colloid group (HES group, n = 16). An intravenous preload of 8 mL/kg of either lactated Ringer's solution in the RS group or 6% hydroxyethyl starch in the HES group was infused within 20 min before SA induction, while no intravenous preload was given in the C group. There was a trend of decrease in CO and systolic blood pressure after SA with time in the C group. In the RS and HES groups, CO increased significantly after fluid preloading as compared with baseline (P < 0.01). Thereafter, CO remained higher than baseline until 30 min after SA in the HES group. The change of systolic blood pressure was similar to CO, but no significant difference from baseline was observed in each group. Hypotension occurred in 3 patients in the C group and one each in the RS and HES group, respectively (P = 0.362). Intravascular volume preload with colloid is more effective than crystalloid solution in maintaining CO, which may be improved the hemodynamic stability in elderly patients during SA.

Xie, Rufeng; Wang, Lizhong; Bao, Hongguang



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

PubMed Central

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

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



Validation of Cardiac Output Measurement by Ultrasound Dilution Technique With Pulmonary Artery Thermodilution in a Pediatric Animal Model  

PubMed Central

Novel COstatus system (Transonic Systems, Inc., NY), based on ultrasound dilution (UD), works off in situ arterial and central venous catheters in pediatric patients to measure cardiac output (CO). The purpose of the present study was to validate CO measurement by UD (COUD) with pulmonary artery (PA) thermodilution (COTD) in a prospective animal study. Ten anesthetized pigs (16–45 kg) were instrumented with pediatric PA, central venous, and peripheral artery catheters. For COUD measurements, normothermic saline (0.5–1.0 ml/kg body weight, up to a maximum of 30 ml) was injected into the venous limb of an arteriovenous loop that was connected between in situ catheters. For COTD measurements, 5–10 ml cold saline was injected into the PA catheter. Sixty-four averaged sets were obtained for comparison. COTD mean was 2.98 ± 1.21 l/min (range 1.33–6.29), and COUD mean was 2.68 ± 1.16 l/min (range 1.33–5.85). This study yielded a correlation r = 0.96, COUD = 0.91* (COTD) ? 0.04 l/min; bias was 0.3 l/min with limits of agreement as ?0.39 to 0.99 l/min; and the percentage error was 23.73% between the methods. CO measurements by UD agreed well with thermodilution measurements in the pediatric swine model.

Thuramalla, Naveen; Searles, Bruce



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

Microsoft Academic Search

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

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



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

PubMed Central

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

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



Dietary Intake and Psychological Assessment of Patients Entering Phase II Cardiac Rehabilitation  

Microsoft Academic Search

LEARNING OUTCOME:To describe dietary intake and psychological status of patients entering Phase II cardiac rehabilitation.Assessment of nutritional intake and psychological status at entry to a Phase II Cardiac Rehabilitation program can aid in individualization of the program. In addition to physical assessment, baseline dietary and psychological assessments were performed on 22 consecutive patients entering cardiac rehabilitation over a seven week

M. S. Weintraub; M. K. Stavros; K. S. Rhodes



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

PubMed Central

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

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



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

NASA Astrophysics Data System (ADS)

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

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



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


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

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



G16R single nucleotide polymorphism but not haplotypes of the ?(2)-adrenergic receptor gene alters cardiac output in humans.  


Variation in genes encoding the ?(2)-adrenergic receptor (ADRB2) and angiotensin-converting enzyme (ACE) may influence Q (cardiac output). The 46G>A (G16R) SNP (single nucleotide polymorphism) has been associated with ?(2)-mediated vasodilation, but the effect of ADRB2 haplotypes on Q has not been studied. Five SNPs within ADRB2 (46G>A, 79C>G, 491C>T, 523C>A and 1053G>C by a pairwise tagging principle) and the I/D (insertion/deletion) polymorphism in ACE were genotyped in 143 subjects. Cardiovascular variables were evaluated by the Model flow method at rest and during incremental cycling exercise. Only the G16R polymorphism was associated with Q. In carriers of the Arg(16) allele, Q(rest) (resting Q) was 0.4 [95% CI (confidence interval), 0.0-0.7] l/min lower than in G16G homozygotes (P=0.048). During exercise, the increase in Q was by 4.7 (95% CI, 4.3-5.2) l/min per litre increase in pulmonary Vo(2) (oxygen uptake) in G16G subjects, but the increase was 0.5 (0.0-0.9) l/min lower in Arg16 carriers (P=0.035). A similar effect size was observed for the Arg16 haplotypes ACCCG and ACCCC. No interaction was found between ADRB2 and ACE polymorphisms. During exercise, the increase in Q was 0.5 (CI, 0.0 -1.0) l/min greater in ACE I/I carriers compared with I/D and D/D subjects (P=0.054). In conclusion, the ADRB2 Arg16 allele in humans is associated with a lower Q both at rest and during exercise, overriding the effects of haplotypes. PMID:23438238

Rokamp, Kim Z; Staalsoe, Jonatan M; Gartmann, Martin; Sletgaard, Anna; Nordsborg, Nicolai B; Secher, Niels H; Nielsen, Henning B; Olsen, Niels V



Dynamic cardiac output regulation at rest, during exercise, and muscle metaboreflex activation: impact of congestive heart failure  

PubMed Central

We tested whether mild and moderate dynamic exercise and muscle metaboreflex activation (MMA) affect dynamic baroreflex control of heart rate (HR) and cardiac output (CO), and the influence of stroke volume (SV) fluctuations on CO regulation in normal (N) and pacing-induced heart failure (HF) dogs by employing transfer function analyses of the relationships between spontaneous changes in left ventricular systolic pressure (LVSP) and HR, LVSP and CO, HR and CO, and SV and CO at low and high frequencies (Lo-F, 0.04–0.15 Hz; Hi-F, 0.15–0.6 Hz). In N dogs, both workloads significantly decreased the gains for LVSP-HR and LVSP-CO in Hi-F, whereas only moderate exercise also reduced the LVSP-CO gain in Lo-F. MMA during mild exercise further decreased the gains for LVSP-HR in both frequencies and for LVSP-CO in Lo-F. MMA during moderate exercise further reduced LVSP-HR gain in Lo-F. Coherence for HR-CO in Hi-F was decreased by exercise and MMA, whereas that in Lo-F was sustained at a high level (>0.8) in all settings. HF significantly decreased dynamic HR and CO regulation in all situations. In HF, the coherence for HR-CO in Lo-F decreased significantly in all settings; the coherence for SV-CO in Lo-F was significantly higher. We conclude that dynamic exercise and MMA reduces dynamic baroreflex control of HR and CO, and these are substantially impaired in HF. In N conditions, HR modulation plays a major role in CO regulation. In HF, influence of HR modulation wanes, and fluctuations of SV dominate in CO variations.

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



Rapid assessment of cardiac contractility on a home bathroom scale.  


Analyzing systolic time intervals-specifically the preejection-period (PEP)-is widely accepted as one of the few methods for the noninvasive assessment of cardiac contractility. In this paper, we investigated the ballistocardiogram (BCG) as a way to noninvasively measure myocardial contractility when combined with the ECG. Specifically, we derived a parameter from the BCG and ECG that we hypothesized would be highly correlated to PEP. This is the time delay between the J-wave peak of the BCG and the R-wave of the ECG, which we refer to as the RJ interval. The RJ interval was correlated to PEP (r(2) = 0.86) for 2126 heartbeats across ten subjects, with a y-intercept of 138 ms and slope of 1.05. This suggests that the RJ interval can be reliably used as a noninvasive assessment of cardiac contractility. PMID:21843998

Etemadi, Mozziyar; Inan, Omer T; Giovangrandi, Laurent; Kovacs, Gregory T A



Acute Heart Failure With Low Cardiac Output: Can We Develop a Short-term Inotropic Agent That Does Not Increase Adverse Events?  

Microsoft Academic Search

Acute heart failure represents an increasingly common cause of hospitalization, and may require the use of inotropic drugs\\u000a in patients with low cardiac output and evidence of organ hypoperfusion. However, currently available therapies may have deleterious\\u000a effects and increase mortality. An ideal inotropic drug should restore effective tissue perfusion by enhancing myocardial\\u000a contractility without causing adverse effects. Such a drug

Umberto Campia; Savina Nodari; Mihai Gheorghiade



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



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



Cardiac Output Measurement in Ventilated Lambs with a Significant Left-to-Right Shunt Using the Modified Carbon Dioxide Fick Method  

Microsoft Academic Search

Background: It remains a great challenge to measure systemic blood flow in critically ill newborns. In a former study we validated the modified carbon dioxide Fick (mCO2F) method for measurement of cardiac output in a newborn lamb model. In this new study we studied the influence of a left-to-right shunt on the accuracy of the mCO2F method. Objective: To analyze

Willem P. de Boode; Jeroen C. W. Hopman; Marc H. W. A. Wijnen; Ronald B. Tanke; Hans G. van der Hoeven; K. Djien Liem



Role of heart rate and stroke volume during muscle metaboreflex-induced cardiac output increase: differences between activation during and after exercise  

Microsoft Academic Search

We hypothesized that the role of stroke volume (SV) in the metaboreflex-induced cardiac output (CO) increase was blunted when\\u000a the metaboreflex was stimulated by exercise muscle ischemia (EMI) compared with post-exercise muscle ischemia (PEMI), because\\u000a during EMI heart rate (HR) increases and limits diastolic filling. Twelve healthy volunteers were recruited and their hemodynamic\\u000a responses to the metaboreflex evoked by EMI,

Antonio Crisafulli; Francesco Piras; Michele Filippi; Carlo Piredda; Paolo Chiappori; Franco Melis; Raffaele Milia; Filippo Tocco; Alberto Concu


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

PubMed Central

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



Prospective Assessment After Pediatric Cardiac Ablation  

PubMed Central

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

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



Assessment of nasal and sinus nitric oxide output using single-breath humming exhalations  

Microsoft Academic Search

Assessment of nasal and sinus nitric oxide output using single-breath humming exhalations. M. Maniscalco, E. Weitzberg, J. Sundberg, M. Sofia, J.O. Lundberg. #ERS Journals Ltd 2003. ABSTRACT: Nasal nitric oxide (NO) levels increase greatly during humming compared to silent exhalation. In this study, the physiological and anatomical factors that regulate NO release during humming have been characterised in 10 healthy

M. Maniscalco; E. Weitzberg; J. Sundbergz; M. Sofia; J. O. Lundberg



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

Microsoft Academic Search

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

Peter W. Barry; Chris O’Callaghan



Prospective Assessment after Pediatric Cardiac Ablation  

PubMed Central

Objectives A multicenter prospective study was performed to assess the results and risks associated with radiofrequency ablation in children. This report focuses on recurrences following initially successful ablation. Methods Patients recruited for the study were aged 0 to 16 years and had supraventricular tachycardia due to accessory pathways or atrioventricular nodal reentrant tachycardia (AVNRT), excluding patients with more than trivial congenital heart disease. A total of 481 patients were recruited into the prospective cohort and were followed at 2, 6, and 12 months following ablation. Results There were 517 successfully ablated substrates out of 540 attempted (95.7%). Loss to follow-up for individual substrates was 3.3%, 10.6%, and 21.2% at 2, 6, and 12 months, respectively. Recurrence was observed in 7.0%, 9.2%, and 10.7% of these substrates at 2, 6, and 12 months, respectively (adjusted for loss to follow-up as an independent source of data censoring). Recurrence rate varied by substrate location (24.6% for right septal, 15.8% for right free wall, 9.3% for left free wall, and 4.8% for left septal), as well as for AVNRT versus all others (4.8% vs 12.9%) at 12 months. The recurrence rate was higher for substrates ablated using power control but was not a function of whether isoproterenol was used for postablation testing. Conclusions Recurrence after initially successful ablation occurs commonly in children. It is least common after AVNRT ablation and most common following ablation of right-sided pathways. These results serve as a benchmark for the time course of recurrence following initially successful ablation of supraventricular tachycardia in children.

Van Hare, George F.; Javitz, Harold; Carmelli, Dorit; Saul, J. Philip; Tanel, Ronn E.; Fischbach, Peter S.; Kanter, Ronald J.; Schaffer, Michael; Dunnigan, Ann; Colan, Steven; Serwer, Gerald



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

PubMed Central

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



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


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



Assessing cardiac and neurological maturation during the intrauterine period.  


The world's first magnetoencephalography (MEG) system specifically designed for fetal and newborn assessment has been installed at the University of Arkansas for Medical Sciences. This noninvasive system called SARA (SQUID Array for Reproductive Assessment) consists of 151 primary superconducting sensors that detect biomagnetic fields from the human body. Since the installation of SARA, significant progress has been made toward the ultimate goal of developing a clinical neurological assessment tool for the developing fetus. Using appropriate analysis techniques, cardiac and brain signals are recorded and studied to gain new understanding of fetal maturation. It is clear from our investigations that a combination of assessment protocols including both fetal heart and brain activity is necessary for the development of a comprehensive new method of fetal neurological testing. We plan to implement such a test protocol for fetuses at high risk for neurological impairment due to certain maternal risk factors and/or fetal diagnostic findings. PMID:18652925

Lowery, Curtis L; Govindan, R B; Murphy, Pamela; Eswaran, Hari



Remote Cardiac Monitoring:A Systematic Review. Technology Assessment Report.  

National Technical Information Service (NTIS)

Remote cardiac monitoring technologies allow home electrocardiographic (ECG) monitoring of patients with suspected cardiac arrhythmias or at risk for developing arrhythmias. Two major categories of remote cardiac monitoring devices are evaluated in this r...



Assessing the link between omega-3 fatty acids, cardiac arrest, and sudden unexpected death in epilepsy  

Microsoft Academic Search

People with epilepsy may have abnormal cardiac function. This has been linked to a greater incidence of sudden unexpected death in epilepsy (SUDEP). In the present review, we assess the evidence linking cardiac failure to SUDEP, and propose the use of the maximal pentylenetetrazol seizure test to model SUDEP in animals to identify causal links between cardiac failure and SUDEP.

Ameer Y. Taha; Flaviu A. Ciobanu; Anjali Saxena; W. McIntyre Burnham



Using climate model output to assess the impacts of climate change on water resources  

SciTech Connect

The use of general circulation models (GCMs) to provide climate data for regional assessments of the impacts of changing climate on water resources stretches the limits of what the models were designed for. Problems that must be addressed include disagreement on a regional scale among GCMs and between the modeled and observed climate; coarse spatial resolution of the models; and simplistic representation of surface hydrology. It is important that continued progress be made in developing the methodology for using GCM output in climate-impact assessments. 18 refs.

Cushman, R.M.



A regional version of a US economic input-output life-cycle assessment model  

Microsoft Academic Search

Background, Aims and Scope  Life cycle assessment models typically use product-specific, plant-level or national aggregate data. However, many decisions\\u000a by regional policy makers would be better informed by local or regional aggregate data. This research is intended to construct\\u000a and apply a regional US economic input-output analysis-based life cycle assessment (REIO-LCA) model based upon publicly available\\u000a datasets. The model uses Gross

Gyorgyi Cicas; Chris T. Hendrickson; Arpad Horvath; H. Scott Matthews



Cardiac output measured by uncalibrated arterial pressure waveform analysis by recently released software version 3.02 versus thermodilution in septic shock.  


To evaluate the 3.02 software version of the FloTrac/Vigileo™ system for estimation of cardiac output by uncalibrated arterial pressure waveform analysis, in septic shock. Nineteen consecutive patients in septic shock were studied. FloTrac/Vigileo™ measurements (COfv) were compared with pulmonary artery catheter thermodilution-derived cardiac output (COtd). The mean cardiac output was 7.7 L min(-1) and measurements correlated at r = 0.53 (P < 0.001, n = 314). In Bland-Altman plot for repeated measurements, the bias was 1.7 L min(-1) and 95 % limits of agreement (LA) were -3.0 to 6.5 L min(-1), with a %error of 53 %. The bias of COfv inversely related to systemic vascular resistance (SVR) (r = -0.54, P < 0.001). Above a SVR of 700 dyn s cm(-5) (n = 74), bias was 0.3 L min(-1) and 95 % LA were -1.6 to 2.2 L min(-1) (%error 32 %). Changes between consecutive measurements (n = 295) correlated at 0.67 (P < 0.001), with a bias of 0.1 % (95 % limits of agreement -17.5 to 17.0 %). All changes >10 % in both COtd and COfv (n = 46) were in the same direction. Eighty-five percent of the measurements were within the 30°-330° of the polar axis. COfv with the latest software still underestimates COtd at low SVR in septic shock. The tracking capacities of the 3.02 software are moderate-good when clinically relevant changes are considered. PMID:23154918

Slagt, Cornelis; de Leeuw, Marcel A; Beute, Jan; Rijnsburger, Emmy; Hoeksema, Martijn; Mulder, Jan W R; Malagon, Ignacio; Groeneveld, A B Johan



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

PubMed Central

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

Arai, Andrew E.



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



Compressing the non-dependent lung during one-lung ventilation improves arterial oxygenation, but impairs systemic oxygen delivery by decreasing cardiac output  

Microsoft Academic Search

Purpose  We have previously found that compression of the non-dependent lung improves arterial oxygenation during one-lung ventilation\\u000a (OLV) in patients undergoing esophagectomy. The purpose of this study was to investigate the effects of compression of the\\u000a non-dependent lung on hemodynamic indices and oxygen delivery using a minimally invasive cardiac output (CO) monitor.\\u000a \\u000a \\u000a \\u000a Methods  Sixteen consecutive patients undergoing esophagectomy through a right thoracotomy

Seiji Ishikawa; Madoka Shirasawa; Michiko Fujisawa; Tatsuyuki Kawano; Koshi Makita



Integrating economic input–output life cycle assessment with risk assessment for a screening-level analysis  

Microsoft Academic Search

Goal, Scope, and Background  The paper describes the integration of the economic input–output life cycle assessment (EIO-LCA) model and the environmental\\u000a fate and transport model (CHEMGL) with a risk assessment tool. Utilizing the EIO-LCA, instead of a traditional LCA, enables\\u000a a rapid, screening-level analysis of an emerging chemical of concern, decabromodiphenyl ether (DecaBDE). The risk assessment\\u000a in this study is evaluated

Heather E. Wright; Qiong Zhang; James R. Mihelcic



Assessment of presence of isolated periodic and aperiodic bands in laser electrophotographic printer output  

NASA Astrophysics Data System (ADS)

Laser electrophotographic printers are complex systems with many rotating components that are used to advance the media, and facilitate the charging, exposure, development, transfer, fusing, and cleaning steps. Irregularities that are constant along the axial direction of a roller or drum, but which are localized in circumference can give rise to distinct isolated bands in the output print that are constant in the scan direction, and which may or may not be observed to repeat at an interval in the process direction that corresponds to the circumference of the roller or drum that is responsible for the artifact. In this paper, we describe an image processing and analysis pipeline that can effectively assess the presence of isolated periodic and aperiodic bands in the output from laser electrophotographic printers. In our paper, we will discuss in detail the algorithms that comprise the image processing and analysis pipeline, and will illustrate the efficacy of the pipeline with an example.

Zhang, Jia; Astling, Stephen; Jessome, Renee; Maggard, Eric; Nelson, Terry; Shaw, Mark; Allebach, Jan P.



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

National Technical Information Service (NTIS)

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

E. Feigenbaum E. Carter



Efficient algorithms for Life Cycle Assessment, Input-Output Analysis, and Monte-Carlo Analysis  

Microsoft Academic Search

Goal, Scope, and Background  As Life Cycle Assessment (LCA) and Input-Output Analysis (IOA) systems increase in size, computation times and memory usage\\u000a can increase rapidly. The use of efficient methods of solution allows the use of a wide range of analysis techniques. Some\\u000a techniques, such as Monte-Carlo Analysis, may be limited if computational times are too slow.\\u000a \\u000a \\u000a \\u000a Discussion of Methods  In this

Glen P. Peters; Realfagbygget E



Cardiac assessment of patients with late stage Duchenne muscular dystrophy.  


Background. Duchenne muscular dystrophy (DMD) patients used to die mainly from pulmonary problems. However, as advances in respiratory care increase life expectancy, mortality due to cardiomyopathy rises. Echocardiography remains the standard diagnostic modality for cardiomyopathy in DMD patients, but is hampered by scoliosis and poor echocardiographic acoustic windows in adult DMD patients. Multigated cardiac radionuclide ventriculography (MUGA) does not suffer from these limitations. N-terminal proBNP (NTproBNP) has shown to be a diagnostic factor for heart failure. We present our initial experience with plasma NT-proBNP measurement in the routine screening and diagnosis of cardiomyopathy in adult mechanically ventilated DMD patients.Methods. Retrospective study, 13 patients. Echocardiography classified left ventricular (LV) function as preserved or depressed. NT-proBNP was determined using immunoassay. LV ejection fraction (LVEF) was determined using MUGA.Results. Median (range) NT-proBNP was 73 (25 to 463) ng/l. Six patients had an NT-proBNP >125 ng/l. Seven patients showed an LVEF <45% on MUGA. DMD patients with depressed LV function (n=4) as assessed by echocardiography had significantly higher median NT-proBNP than those (n=9) with preserved LV function: 346 (266 to 463) ng/l versus 69 (25 to 257) ng/l (p=0.003). NT-proBNP significantly correlated with depressed LV function on echocardiogram and with LVEF determined by MUGA.Conclusion. Although image quality of MUGA is superior to echocardiography, the combination of echocardiography and NT-proBNP achieves similar results in the evaluation of left ventricular function and is less time consuming and burdensome for our patients. We advise to add NT-proBNP to echocardiography in the routine cardiac assessment of DMD patients. (Neth Heart J 2009;17:232-7.). PMID:19789685

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



Cardiac assessment of patients with late stage Duchenne muscular dystrophy  

PubMed Central

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

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



Cardiac output in idiopathic normal pressure hydrocephalus: association with arterial blood pressure and intracranial pressure wave amplitudes and outcome of shunt surgery  

PubMed Central

Background In patients with idiopathic normal pressure hydrocephalus (iNPH) responding to shunt surgery, we have consistently found elevated intracranial pressure (ICP) wave amplitudes during diagnostic ICP monitoring prior to surgery. It remains unknown why ICP wave amplitudes are increased in these patients. Since iNPH is accompanied by a high incidence of vascular co-morbidity, a possible explanation is that there is reduced vascular compliance accompanied by elevated arterial blood pressure (ABP) wave amplitudes and even altered cardiac output (CO). To investigate this possibility, the present study was undertaken to continuously monitor CO to determine if it is correlated to ABP and ICP wave amplitudes and the outcome of shunting in iNPH patients. It was specifically addressed whether the increased ICP wave amplitudes seen in iNPH shunt responders were accompanied by elevated CO and/or ABP wave amplitude levels. Methods Prospective iNPH patients (29) were clinically graded using an NPH grading scale. Continuous overnight minimally-invasive monitoring of CO and ABP was done simultaneously with ICP monitoring; the CO, ABP, and ICP parameters were parsed into 6-second time windows. Patients were assessed for shunt surgery on clinical grade, Evan's index, and ICP wave amplitude. Follow-up clinical grading was performed 12 months after surgery. Results ICP wave amplitudes but not CO or ABP wave amplitude, showed good correlation with the response to shunt treatment. The patients with high ICP wave amplitude did not have accompanying high levels of CO or ABP wave amplitude. Correlation analysis between CO and ICP wave amplitudes in individual patients showed different profiles [significantly positive in 10 (35%) and significantly negative in 16 (55%) of 29 recordings]. This depended on whether there was also a correlation between ABP and ICP wave amplitudes and on the average level of ICP wave amplitude. Conclusions These results gave no evidence that the increased levels of ICP wave amplitudes seen in iNPH shunt responders prior to surgery were accompanied by elevated levels of ABP wave amplitudes or elevated CO. In the individual patients the correlation between CO and ICP wave amplitude was partly related to an association between ABP and ICP wave amplitudes which can be indicative of the state of cerebrovascular pressure regulation, and partly related to the ICP wave amplitude which can be indicative of the intracranial compliance.



Computerized assessment and tracking of cardiac angiographic image quality  

NASA Astrophysics Data System (ADS)

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

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



Assessment of cardiac volumes using an isotropic whole-heart dual cardiac phase sequence in pediatric patients.  


PURPOSE: To evaluate the accuracy of a three-dimensional dual phase (3D DP) whole-heart technique for cardiac volumetric assessment in pediatric patients with cardiac abnormalities. MATERIALS AND METHODS: The institutional approved this study, and informed consent was obtained from patients or their guardians. This prospective study involved 31 pediatric patients (mean age, 7.9 years; range, 15 days to 15 years) for the assessment of cardiac abnormalities using cardiovascular MR. A standard protocol was performed for assessing cardiac anatomy and function. For evaluating the 3D DP technique, statistical comparison with a 2D cine multi-slice technique (2D steady-state free-precession [SSFP]) was performed using linear regression, intraclass correlation coefficient, and Bland Altman plots. RESULTS: Left (LV) and right (RV) ventricular cardiac volumes obtained with the 3D DP technique were in strong agreement with those obtained with the 2D SSFP technique for small and large ventricular volumes. The intraclass correlation coefficients (ICC) between both techniques were 0.992 for the LV end-diastolic volume (EDV), 0.983 for the LV end-systolic volume (ESV), 0.952 for the LV-systolic volume (SV), 0.992 for the RV-EDV, 0.992 for the RV-ESV, 0.928 for the RV-SV. Interobserver analysis indicated good reproducibility for both the 2D SSFP and the 3D DP techniques. CONCLUSION: The 3D DP technique provides as accurate cardiac volumes as the 2D SSFP technique in the pediatric population, but with the added benefits of easier data acquisition and detailed anatomical information of the whole heart and great vessels in a single free-breathing scan. J. Magn. Reson. Imaging 2013;. © 2013 Wiley Periodicals, Inc. PMID:23723135

Delgado, Jorge A; Abad, Pedro; Rascovsky, Simon; Calvo, Victor; Castrillon, Gabriel; Greil, Gerald; Uribe, Sergio



Environmental impact assessment including indirect effects--a case study using input-output analysis  

SciTech Connect

Environmental impact assessment (EIA) is a process covered by several international standards, dictating that as many environmental aspects as possible should be identified in a project appraisal. While the ISO 14011 standard stipulates a broad-ranging study, off-site, indirect impacts are not specifically required for an Environmental Impact Statement (EIS). The reasons for this may relate to the perceived difficulty of measuring off-site impacts, or the assumption that these are a relatively insignificant component of the total impact. In this work, we describe a method that uses input-output analysis to calculate the indirect effects of a development proposal in terms of several indicator variables. The results of our case study of a Second Sydney Airport show that the total impacts are considerably higher than the on-site impacts for the indicators land disturbance, greenhouse gas emissions, water use, emissions of NO{sub x} and SO{sub 2}, and employment. We conclude that employing input-output analysis enhances conventional EIA, as it allows for national and international effects to be taken into account in the decision-making process.

Lenzen, Manfred; Murray, Shauna A.; Korte, Britta; Dey, Christopher J



[Summary of the consensus document: "Clinical practice guide for the management of low cardiac output syndrome in the postoperative period of heart surgery"].  


Low cardiac output syndrome is a potential complication in cardiac surgery patients and is associated with increased morbidity and mortality. This guide provides recommendations for the management of these patients, immediately after surgery and following admission to the ICU. The recommendations are grouped into different sections, addressing from the most basic concepts such as definition of the disorder to the different sections of basic and advanced monitoring, and culminating with the complex management of this syndrome. We propose an algorithm for initial management, as well as two others for ventricular failure (predominantly left or right). Most of the recommendations are based on expert consensus, due to the lack of randomized trials of adequate design and sample size in patients of this kind. The quality of evidence and strength of the recommendations were based on the GRADE methodology. The guide is presented as a list of recommendations (with the level of evidence for each recommendation) for each question on the selected topic. For each question, justification of the recommendations is then provided. PMID:22445904

Pérez Vela, J L; Martín Benitez, J C; Carrasco Gonzalez, M; de la Cal López, M A; Hinojosa Pérez, R; Sagredo Meneses, V; del Nogal Saez, F



Infant Temperament and Cardiac Vagal Tone: Assessments at Twelve Weeks of Age.  

ERIC Educational Resources Information Center

Explored relation between temperament and cardiac vagal tone in 12-week olds. Found that infants with higher baseline vagal tone showed fewer negative behaviors in the laboratory and were less disrupted by experimental procedures than infants with lower baselines. Infants who decreased cardiac vagal tone during assessments were rated by mothers as…

Huffman, Lynne C.; And Others



Psychosocial outcome assessments for use in cardiac rehabilitation service evaluation: a 10-year systematic review  

Microsoft Academic Search

A variety of measures are currently used to assess psychosocial outcome (quality of life) in cardiac rehabilitation programmes. However, there is no consensus on the most appropriate instruments to use. Instruments that are not sufficiently responsive to change in cardiac populations are unsuitable as audit tools as they underrepresent the benefits of programme attendance. To identify the most responsive instruments

H. M. McGee; D. Hevey; J. H. Horgan




Microsoft Academic Search

End users and distributors of PV modules are often faced with the problem of how to verify the power output specification of a new shipment consisting of a larger number of PV modules. As a first step, claims can be based on the data sheet containing information on the nominal power output (related to STC) and the power output tolerance.

W. Herrmann; J. Althaus; A. Steland; H. Zähle


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


The interpretation of the heart as a mechanical engine dates back to the teachings of Leonardo da Vinci, who was the first to apply the laws of mechanics to the function of the heart. Similar to any mechanical engine, whose performance is proportional to the power generated with respect to weight, the left ventricle can be viewed as a power generator whose performance can be related to left ventricular mass. Stress echocardiography may provide valuable information on the relationship between cardiac performance and recruited left ventricular mass that may be used in distinguishing between adaptive and maladaptive left ventricular remodeling. Peak power output-to-mass, obtained during exercise or pharmacological stress echocardiography, is a measure that reflects the number of watts that are developed by 100 g of left ventricular mass under maximal stimulation. Power output-to-mass may be calculated as left ventricular power output per 100 g of left ventricular mass: 100× left ventricular power output divided by left ventricular mass (W/100 g). A simplified formula to calculate power output-to-mass is as follows: 0.222 × cardiac output (l/min) × mean blood pressure (mmHg)/left ventricular mass (g). When the integrity of myocardial structure is compromised, a mismatch becomes apparent between maximal cardiac power output and left ventricular mass; when this occurs, a reduction of the peak power output-to-mass index is observed. PMID:21934524

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



Assessment of cardiac parameters in evaluation of cardiac functions in patients with thalassemia major.  


The aim of the study was to evaluate cardiac function and early cardiac dysfunction of patients followed as thalassemia major. In this study, the authors compared 100 patients, diagnosed as thalassemia major with mean age 11.84 ± 4.35, with 60 healthy control subjects at the same age between 2008 and 2011. Early diagnosis of iron overload that may occur after repeated transfusions is important in this patient group. To detect early iron accumulation, the authors compared ferritin with the echo findings, the 24-hour Holter, and cardiac magnetic resonance imaging (MRI) T2* values in the patients of same age and sex, treated with chelators, without heart failure, nonsplenectomized, and do not differ in the presence of hepatitis C. Ferritin levels, left ventricular systolic functions (ejection fraction [EF], shortening fraction [SF]), left ventricular measurements, left ventricular diastolic functions, T2* image on cardiac magnetic resonance, heart rate variables in 24 hours, and Holter rhythm were evaluated to show the early failure of cardiac functions. In this study the authors confirmed that iron-related cardiac toxicity damages electrical activity earlier than myocardial contractility. Left ventricular diastolic diameter (LVDd), left ventricular mass (LVM), and LV systolic diameter (LVDs) levels were significantly higher in the patient group with ectopia. Patients with ectopia are the ones in whom LVM and LVDd are increased. In thalassemia major patients with ectopia, LF/HF ratio was markedly increased, QTc dispersion was clearly found higher in patients with ectopia rather than nonectopic patients. The standard deviation all normal RR interval series (SDNN) was found clearly lower in thalassemia major group with ectopia than control group because it is assumed that increase in cardiac sympathetic neuronal activity is related to exposure to chronic diastolic and systolic failure. PMID:22475298

Oztarhan, Kazim; Delibas, Yavuz; Salcioglu, Zafer; Kaya, Guldemet; Bakari, Suleyman; Bornaun, Helen; Aydogan, Gonul



Imminent cardiac risk assessment via optical intravascular biochemical analysis.  


Heart disease is by far the biggest killer in the United States, and type II diabetes, which affects 8% of the U.S. population, is on the rise. In many cases, the acute coronary syndrome and/or sudden cardiac death occurs without warning. Atherosclerosis has known behavioral, genetic and dietary risk factors. However, our laboratory studies with animal models and human post-mortem tissue using FT-IR microspectroscopy reveal the chemical microstructure within arteries and in the arterial walls themselves. These include spectra obtained from the aortas of ApoE-/- knockout mice on sucrose and normal diets showing lipid deposition in the former case. Also pre-aneurysm chemical images of knockout mouse aorta walls, and spectra of plaque excised from a living human patient are shown for comparison. In keeping with the theme of the SPEC 2008 conference 'Spectroscopic Diagnosis of Disease...' this paper describes the background and potential value of a new catheter-based system to provide in vivo biochemical analysis of plaque in human coronary arteries. We report the following: (1) results of FT-IR microspectroscopy on animal models of vascular disease to illustrate the localized chemical distinctions between pathological and normal tissue, (2) current diagnostic techniques used for risk assessment of patients with potential unstable coronary syndromes, and (3) the advantages and limitations of each of these techniques illustrated with patent care histories, related in the first person, by the physician coauthors. Note that the physician comments clarify the contribution of each diagnostic technique to imminent cardiac risk assessment in a clinical setting, leading to the appreciation of what localized intravascular chemical analysis can contribute as an add-on diagnostic tool. The quality of medical imaging has improved dramatically since the turn of the century. Among clinical non-invasive diagnostic tools, laboratory tests of body fluids, EKG, and physical examination are still the first line of defense. However, with the fidelity of 64-slice CT imaging, this technique has recently become an option when the patient presents with symptoms of reduced arterial flow. Single photon emission computerized tomography (SPECT) treadmill exercise testing is a standard non-invasive test for decreased perfusion of heart muscle, but is time consuming and not suited for emergent evaluation. Once the invasive clinical option of catherization is chosen, this provides the opportunity for intravascular ultrasound (IVUS) imaging. As the probe is pulled through the artery, the diameter at different parts is measurable, and monochrome contrast in the constricted area reveals the presence of tissue with a different ultrasonic response. Also, via an optical catheter with a fiber-optic conductor, the possibly of spectroscopic analysis of arterial walls is now a reality. In this case, the optical transducer is coupled to a near-infrared spectrometer. Revealing the arterial chemical health means that plaque vulnerability and imminent risk could be assessed by the physician. The classical emergency use of catherization involves a contrast agent and dynamic X-ray imaging to locate the constriction, determine its severity, and possibly perform angioplasty, and stent placement. PMID:19475135

Wetzel, David L; Wetzel, Louis H; Wetzel, Mark D; Lodder, Robert A



Assessment of survey radiography as a method for diagnosis of congenital cardiac disease in dogs.  


In order to assess the diagnostic accuracy of survey radiography for canine congenital cardiac anomalies, thoracic radiographs of 57 dogs with congenital cardiac anomalies, 31 normal dogs and 27 dogs with acquired cardiac disease were mixed, and reviewed by two independent observers, who were blinded to any patient information. The congenital anomalies were aortic stenosis (n=25), pulmonic stenosis (n=10), patent ductus arteriosus (n=9), ventricular septal defect (n=8), tricuspid dysplasia (n=3) and mitral dysplasia (n=2). Both observers were moderately accurate at identifying dogs with cardiac disease. Their ability to distinguish dogs with congenital versus acquired cardiac disease was poorer and this assessment was probably influenced by the recognition of patients that were skeletally immature, which biased observers towards a diagnosis of congenital cardiac anomaly. The diagnosis rate for specific congenital anomalies was also poor (the differential list included a correct diagnosis in only 40 and 37 per cent of cases). Radiographic signs of specific cardiac chamber enlargement or pulmonary vascular abnormalities were recognised by both observers in only 20 per cent of instances in which they might be expected. They were, however, recognised more frequently in dogs with anomalies that imposed a volume load on the heart than in dogs with anomalies that induced a pressure load on the organ. It is concluded that survey radiography is an inaccurate method for diagnosis of canine congenital cardiac anomalies because of the difficulty of recognising radiographic signs, which are not present in many cases. PMID:11721982

Lamb, C R; Boswood, A; Volkman, A; Connolly, D J



Assessing the inputs and outputs of partnership arrangements for health and safety management  

Microsoft Academic Search

Partnerships have the potential to create significant benefits for all participants provided that there is a mutual understanding of and respect for the inputs required and the outputs sought from the arrangements by each party. The aim of this study was to explore the inputs required and the outputs achieved by partners as a function of the level of involvement

L. H. Vassie; C. W. Fuller



Role Of Cardiac Mri In The Assessment Of Nonischemic Cardiomyopathies  

PubMed Central

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

Nabi, Faisal



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

Microsoft Academic Search

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

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



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

Microsoft Academic Search

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

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



Cross-comparison of cardiac output trending accuracy of LiDCO, PiCCO, FloTrac and pulmonary artery catheters  

PubMed Central

Introduction Although less invasive than pulmonary artery catheters (PACs), arterial pulse pressure analysis techniques for estimating cardiac output (CO) have not been simultaneously compared to PAC bolus thermodilution CO (COtd) or continuous CO (CCO) devices. Methods We compared the accuracy, bias and trending ability of LiDCO™, PiCCO™ and FloTrac™ with PACs (COtd, CCO) to simultaneously track CO in a prospective observational study in 17 postoperative cardiac surgery patients for the first 4 hours following intensive care unit admission. Fifty-five paired simultaneous quadruple CO measurements were made before and after therapeutic interventions (volume, vasopressor/dilator, and inotrope). Results Mean CO values for PAC, LiDCO, PiCCO and FloTrac were similar (5.6 ± 1.5, 5.4 ± 1.6, 5.4 ± 1.5 and 6.1 ± 1.9 L/min, respectively). The mean CO bias by each paired method was -0.18 (PAC-LiDCO), 0.24 (PAC-PiCCO), -0.43 (PAC-FloTrac), 0.06 (LiDCO-PiCCO), -0.63 (LiDCO-FloTrac) and -0.67 L/min (PiCCO-FloTrac), with limits of agreement (1.96 standard deviation, 95% confidence interval) of ± 1.56, ± 2.22, ± 3.37, ± 2.03, ± 2.97 and ± 3.44 L/min, respectively. The instantaneous directional changes between any paired CO measurements displayed 74% (PAC-LiDCO), 72% (PAC-PiCCO), 59% (PAC-FloTrac), 70% (LiDCO-PiCCO), 71% (LiDCO-FloTrac) and 63% (PiCCO-FloTrac) concordance, but poor correlation (r2 = 0.36, 0.11, 0.08, 0.20, 0.23 and 0.11, respectively). For mean CO < 5 L/min measured by each paired devices, the bias decreased slightly. Conclusions Although PAC (COTD/CCO), FloTrac, LiDCO and PiCCO display similar mean CO values, they often trend differently in response to therapy and show different interdevice agreement. In the clinically relevant low CO range (< 5 L/min), agreement improved slightly. Thus, utility and validation studies using only one CO device may potentially not be extrapolated to equivalency of using another similar device.



Utility of cardiac magnetic resonance in assessing right-sided heart failure in sarcoidosis  

PubMed Central

Background Cardiac involvement in sarcoidosis is associated with a poor prognosis. In patients with right sided heart failure, differentiating between cor-pulmonale, or cardiac sarcoidosis has important implications to management. Case presentation We present the case of a patient with severe but stable pulmonary sarcoidosis and new onset right sided heart failure despite only mild elevations of pulmonary artery pressure. CMR demonstration of extensive right ventricular fibrosis with associated dilatation and hypokinesis was a key finding for prognosis and management of the patient. Conclusion Cardiac magnetic resonance (CMR) is the preferred investigation in the diagnosis of cardiac sarcoidosis, allowing assessment of myocardial inflammation and fibrosis, as well as function, in a manner not matched by other technologies.



In vivo assessment of cardiac remodeling after myocardial infarction in rats by cine-magnetic resonance imaging.  


The rat infarct model offers important parallels to the process of remodeling after myocardial infarction (MI) in humans. The aim of this study was to test the feasibility of cine fast low-angle shot (FLASH) magnetic resonance imaging (MRI) for assessment of the infarcted and noninfarcted rat heart and to compare the results with established methods. In group A, MRI was done 8-16 weeks after MI on a 7-T scanner using an electrocardiogram-triggered cine-FLASH sequence. We determined left ventricular (LV) volumes and mass, wall thickness, MI size, cardiac output, and ejection fraction. Afterward, MI size was histologically determined. In group B, after MRI eight controls and eight rats 16 weeks after MI underwent conventional hemodynamic measurements for determination of cardiac output, LV volumes, and ejection fraction by electromagnetic flowmeter and pressure-volume curves. LV wet weight was determined. In group A, MRI-acquired MI size (18.5 +/- 2%) was smaller than histology (22.8 +/- 2.5%, p < 0.05) with close correlation (r = 0.97). In group B, agreement in LV mass was found between MRI and wet weight (controls, 537.6 +/- 19.6 vs. 540.3 +/- 18.4 mg; MI, 865.1 +/- 39.2 vs. 865.1 +/- 41.3 mg; for the difference p = ns, r = 0.97, p < 0.05) and in the MRI and flowmeter measurements (cardiac output, controls 73.1 +/- 2.9 vs. 75.2 +/- 2.6 ml/min; MI 82.4 +/- 5.2 vs. 81.9 +/- 3.7 ml/min; for the difference p = ns, r = 0.80, p < 0.05). End-diastolic volume by MRI differed from pressure-volume curves with good correlation (controls, 343.9 +/- 8.4 vs. 262.7 +/- 12.8 microl; MI, 737.0 +/- 70.5 vs. 671.1 +/- 64.1 microl; p < 0.05 each, r = 0.96, p < 0.05). Cine-FLASH-MRI is a valuable diagnostic tool applicable to the rat model of MI. Being noninvasive and exact, it offers new insights in the remodeling process after MI because serial measurements are possible. PMID:11545114

Nahrendorf, M; Wiesmann, F; Hiller, K H; Han, H; Hu, K; Waller, C; Ruff, J; Haase, A; Ertl, G; Bauer, W R



Heat shock protein 27 is increased in cyanotic tetralogy of Fallot myocardium and is associated with improved cardiac output and contraction.  


Tetralogy of Fallot (TOF) is a congenital heart condition in which the right ventricle is exposed to cyanosis and pressure overload. Patients have an increased risk of right ventricle dysfunction following corrective surgery. Whether the cyanotic myocardium is less tolerant of injury compared to non-cyanotic is unclear. Heat shock proteins (HSPs) protect against cellular stresses. The aim of this study was to examine HSP 27 expression in the right ventricle resected from TOF patients and determine its relationship with right ventricle function and clinical outcome. Ten cyanotic and ten non-cyanotic patients were studied. Western blotting was used to quantify HSP 27 in resected myocardium at (1) baseline (first 15 min of aortic cross clamp and closest representation of pre-operative status) and (2) after 15 min during ischemia until surgery was complete. The cyanotic group had significantly increased haematocrit, lower O2 saturation, thicker interventricular septal wall thickness and released more troponin-I on post-operative day 1 (p < 0.05). HSP 27 expression was significantly increased in the < 15 min cyanotic compared to the < 15 min non-cyanotic group (p = 0.03). In the cyanotic group, baseline HSP 27 expression also significantly correlated with oxygen extraction ratio (p = 0.028), post-operative basal septal velocity (p = 0.036) and mixed venous oxygen saturation (p = 0.02), markers of improved cardiac output/contraction. Increased HSP 27 expression and associated improved right ventricle function and systemic perfusion supports a cardio-protective effect of HSP 27 in cyanotic TOF. PMID:23080524

Walker, Susan; Danton, Mark; Peng, Edward Weng Koon; Lyall, Fiona



Varying the heart rate response to dynamic exercise in pacemaker-dependent subjects: effects on cardiac output and cerebral blood velocity.  


Cerebral blood flow increases upon the transition from rest to moderate exercise, but becomes affected when the ability to raise CO (cardiac output) is limited. HR (heart rate) is considered to contribute significantly to the increase in CO in the early stages of dynamic exercise. The aim of the present study was to test whether manipulation of the HR response in patients dependent on permanent rate-responsive ventricular pacing contributes to the increase in CO, MCA V(mean) [mean MCA (middle cerebral artery) velocity] and work capacity during exercise. The effect of setting the pacemaker to DSS ('default' sensor setting) compared with OSS ('optimized' sensor setting) on blood pressure, CO, SV (stroke volume) and MCA V(mean) was evaluated during ergometry cycling. From rest to exercise at 75 W, the rise in HR in OSS [from 73 (65-87) to 116 (73-152) beats/min; P<0.05] compared with DSS [70 (60-76) to 97 (67-117) beats/min; P<0.05] was larger. There was an increase in SV during exercise with DSS, but not with OSS, such that, at all workloads, SVs were greater during DSS than OSS. The slope of the HR-CO relationship was larger with DSS than OSS (P<0.05). From rest to exercise, MCA V(sys) (systolic MCA velocity) increased in OSS and DSS, and MCA V(dias) (diastolic MCA velocity) was reduced with DSS. No changes were observed in MCA V(mean). Manipulation of the pacemaker setting had no effect on the maximal workload [133 (100-225) W in OSS compared with 129 (75-200) W in DSS]. The results indicate that, in pacemaker-dependent subjects with complete heart block and preserved myocardial function, enhancing the HR response to exercise neither augments CO by a proportional offset of the exercise-induced increase in SV nor improves cerebral perfusion. PMID:16038616

Bogert, Lysander W J; Erol-Yilmaz, Ayten; Tukkie, Raymond; Van Lieshout, Johannes J



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

ERIC Educational Resources Information Center

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

Aristovnik, Aleksander



Critical infrastructure dependency assessment using the input–output inoperability model  

Microsoft Academic Search

The input–output inoperability model (IIM) is a simple, but powerful, mechanism for analyzing the cascading effects induced by critical infrastructure dependencies and interdependencies. IIM typically uses financial data as a measure of the dependency phenomena. Since financial data is only one of the many dimensions for analyzing dependency phenomena, the quality of IIM parameters and, thus, the reliability of IIM

Roberto Setola; Stefano De Porcellinis; Marino Sforna



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

ERIC Educational Resources Information Center

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

Houck, Eric A.; Eom, Moonyoung



A mathematical model for patient skin dose assessment in cardiac catheterization procedures.  


A mathematical model has been developed for the assessment of patient skin doses from cardiac catheterization procedures. This uses exposure and projection data stored in the DICOM image files. Since these contain only information about the acquisition runs, a correction is needed to estimate and include the contribution from fluoroscopy. Maximum skin doses calculated by the model were found to correlate well with those measured on Kodak EDR2 film. Three methods for including the contribution from fluoroscopy were investigated, and all successfully identified patients receiving skin doses in excess of 1 Gy. It is hoped to automate this tool for routine assessment of skin doses in our cardiac catheterization laboratories. PMID:16940375

Morrell, R E; Rogers, A T



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

Microsoft Academic Search

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

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



Short-Term Effects of Transjugular Intrahepatic Shunt on Cardiac Function Assessed by Cardiac MRI: Preliminary Results  

SciTech Connect

The purpose of this study was to assess short-term effects of transjugular intrahepatic shunt (TIPS) on cardiac function with cardiac magnetic resonance imaging (MRI) in patients with liver cirrhosis. Eleven patients (six males and five females) with intractable esophageal varices or refractory ascites were imaged with MRI at 1.5 T prior to, within 24 h after, and 4-6 months after TIPS creation (n = 5). Invasive pressures were registered during TIPS creation. MRI consisted of a stack of contiguous slices as well as phase contrast images at all four valve planes and perpendicular to the portal vein. Imaging data were analyzed through time-volume curves and first derivatives. The portoatrial pressure gradient decreased from 19.8 {+-} 2.3 to 6.6 {+-} 2.3, accompanied by a nearly two fold increase in central pressures and pulmonary capillary wedge pressure immediately after TIPS creation. Left and right end diastolic volumes and stroke volumes increased by 11, 13, and 24%, respectively (p < 0.001), but dropped back to baseline at follow-up. End systolic volumes remained unchanged. E/A ratios remained within normal range. During follow-up the left ventricular mass was larger than baseline values in all patients, with an average increase of 7.9 g (p < 0.001). In conclusion, the increased volume load shunted to the heart after TIPS creation transiently exceeded the preload reserve of the right and left ventricle, leading to significantly increased pulmonary wedge pressures and persistent enlargement of the left and right atria. Normalization of cardiac dimensions was observed after months together with mild left ventricular hypertrophy.

Kovacs, A., E-mail: Attila.Kovacs@ukb.uni-bonn.d [University of Bonn, Department of Radiology (Germany); Schepke, M.; Heller, J. [University of Bonn, Department of Internal Medicine I (Germany); Schild, H. H.; Flacke, S. [University of Bonn, Department of Radiology (Germany)



Ultrasonography assessment of vocal cords mobility in children after cardiac surgery  

PubMed Central

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

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



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

PubMed Central

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

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



Uncertainty Assessment in Long-lead Drought Prediction Using GCMs Outputs  

NASA Astrophysics Data System (ADS)

Drought is one of the major hazards that could cause excessive damages especially in arid and semiarid regions. A study by international panel on climate changes (IPCC) showed that the frequency of drought is increasing because of climate change impact. In this study certain scenarios on climate change that are included in the outputs of the GCM models, are considered in order to evaluate climate change effects on the characteristics of future drought events. For this purpose, different indices that reflect different aspects of drought impacts are considered. These indices consider precipitation, water supply and soil moisture variations in the drought periods. These indices are integrated through a hybrid index that is calculated based on drought damages using Probabilistic Neural Network (PNN). The drought characteristics are then estimated using the proposed algorithm over a one hundred year time horizon that the GCM outputs are available. For evaluation of the uncertainties in the long lead drought prediction, one hundred ensemble data are generated using Statistical Down Scaling Model (SDSM). Uncertainty analysis has been done by fitting probability distribution function to the ensemble results of the drought characteristics prediction. A small basin located at the northwestern part of Iran is used as the case study. The results of this study can be utilized by decision makers in the region to decide on future development plans of the basin and for developing drought emergency plans.

Karamouz, M.; Nazif, S.; Rasouli, K.



Improved Cardiac Risk Assessment with Non-Invasive measures of Coronary flow reserve  

PubMed Central

Background Impaired vasodilator function is an early manifestation of coronary artery disease and may precede angiographic stenosis. It is unknown whether non-invasive assessment of coronary vasodilator function in patients with suspected or known coronary artery disease (CAD) carries incremental prognostic significance. Methods and Results 2783 consecutive patients referred for rest/stress PET were followed for a median of 1.4 years (inter-quartile range: 0.7–3.2 years). The extent and severity of perfusion abnormalities were quantified by visual evaluation of myocardial perfusion images (MPI). Rest and stress myocardial blood flow (MBF) were calculated using factor analysis and a 2-compartment kinetic model, and were used to compute coronary flow reserve (CFR=stress/rest MBF). The primary endpoint was cardiac death. Overall 3-year cardiac mortality was 8.0%. The lowest tertile of CFR (<1.5) was associated with a 5.6-fold increase in the risk of cardiac death (95%CI 2.5–12.4, p<0.0001) compared to the highest tertile. Incorporation of CFR into cardiac death risk assessment models resulted in an increase in the c-index from 0.82 (95%CI 0.78–0.86) to 0.84 (95%CI 0.80–0.87, p=0.02) and in a net reclassification improvement (NRI) of 0.098 (95%CI 0.025–0.180). Addition of CFR resulted in correct reclassification of 34.8% of intermediate risk patients (NRI=0.487, 95%CI 0.262–0.731). Corresponding improvements in risk assessment for mortality from any cause were also demonstrated. Conclusions Non-invasive quantitative assessment of coronary vasodilator function using PET is a powerful, independent predictor of cardiac mortality in patients with known or suspected CAD and provides meaningful incremental risk stratification over clinical and gated MPI variables.

Murthy, Venkatesh L.; Naya, Masanao; Foster, Courtney R.; Hainer, Jon; Gaber, Mariya; Di Carli, Gilda; Blankstein, Ron; Dorbala, Sharmila; Sitek, Arkadiusz; Pencina, Michael J.; Di Carli, Marcelo F.



Assessment of myocardial abnormalities in rheumatoid arthritis using a comprehensive cardiac magnetic resonance approach: a pilot study  

Microsoft Academic Search

INTRODUCTION: Rheumatoid arthritis (RA) is a multi-organ inflammatory disorder associated with high cardiovascular morbidity and mortality. We sought to assess cardiac involvement using a comprehensive cardiac magnetic resonance imaging (cMRI) approach and to determine its association with disease characteristics in RA patients without symptomatic cardiac disease. METHODS: RA patients with no history and\\/or clinical findings of systemic or pulmonary hypertension,

Yasuyuki Kobayashi; Jon T Giles; Masaharu Hirano; Isamu Yokoe; Yasuo Nakajima; Joan M Bathon; Joao AC Lima; Hitomi Kobayashi



Assessing impacts of climate change in a semi arid watershed using downscaled IPCC climate output  

Microsoft Academic Search

This presentation discusses our research aimed at helping water managers at Salt River Project (SRP), Phoenix, assess long term climate change impacts for the Salt and Verde River basins, and make informed policy decisions. Our goal was to assess the future 100 year water balance by development, application and testing of a physically based distributed hydrologic model forced by downscaled

S. Rajagopal; F. Dominguez; H. V. Gupta; P. A. Troch; C. L. Castro



The Hirsch-index: a simple, new tool for the assessment of scientific output of individual scientists  

PubMed Central

In this brief paper we explore the Hirsch-index together with a couple of other bibliometric parameters for the assessment of the scientific output of 29 Dutch professors in clinical cardiology. It appears that even within such a homogeneous group there is large interindividual variability. Although the differences are quite remarkable, it remains undetermined what they mean; at least it is premature to interpret them as differences in scientific quality. It goes without saying that even more prudence is required when different fields of medicine and life sciences are compared (for example within University Medical Centres). Recent efforts to produce an amalgam of scientific ‘productivity’, ‘relevance’ and ‘viability’ as a surrogate parameter for the assessment of scientific quality, as for example performed in the AMC in Amsterdam, should be discouraged in the absence of a firm scientific base. Unfortunately for politicians and ‘managers of science’ only reading papers and studying are suitable for quality assessment of scientific output. Citations analyses can't substitute that. (Neth Heart J 2009;17:145-54.19421360) PMID:19421360

Opthof, T.; Wilde, A.A.M.



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

NASA Astrophysics Data System (ADS)

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

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



Animal welfare assessment at slaughter in Europe: moving from inputs to outputs.  


Producers, retailers and other food chain actors increasingly recognize that consumer concerns for good animal welfare represent a business opportunity that could be profitably incorporated into their commercial strategies. Therefore, during the last decade, numerous trade groups (producers, processors, retailers and restaurant chains) have developed certification systems with their suppliers which include elements of animal welfare. The Welfare Quality® project has developed an integrated and standardised welfare assessment system based on twelve welfare criteria grouped into four main principles (good feeding, good housing, good health and appropriate behaviour) according to how they are experienced by animals. One of the innovations of the Welfare Quality® assessment system is that it focuses more on outcome measures (e.g. directly related to animal body condition, health aspects, injuries, behaviour, etc.). This paper has the objective to discuss the rationale behind the welfare assessment and to describe the Welfare Quality® assessment of pigs and cattle at the slaughterhouse. PMID:22551869

Velarde, Antonio; Dalmau, Antoni



Bleeding risk assessment using whole blood impedance aggregometry and rotational thromboelastometry in patients following cardiac surgery.  


Excessive bleeding after cardiopulmonary bypass (CPB) is risk factor for adverse outcomes after elective cardiac surgery (ECS). Differentiating between patients who bleed due to surgical issues and those whose excessive chest tube output (CTO) is due to coagulopathy, remains challenging. Bedside suitable tests to identify hemostatic disturbances and predict excessive bleeding are desirable. The study sought to evaluate prediction of excessive bleeding after ECS using two bedside suitable devices for platelet function and viscoelastic blood clot properties assessment. We enrolled 148 patients (105 male and 43 female) undergoing ECS in a prospective observational study. Patients were characterized as bleeders if their 24 h CTO exceeded the 75th percentile of distribution. Multiple electrode aggregometry (MEA, with ASPI, ADP and the TRAP test) and rotational thromboelastometry (TEM, with ExTEM, HepTEM and FibTEM test), were performed at three time points: preoperatively (T1), during CPB (T2), and after protamine administration (T3). The primary endpoint was CTO and the secondary endpoint was administration of blood products, 30-day and 1 year mortality. The best predictors of increased bleeding tendency were the tests performed after protamine administration (T3). At T3, patients characterized as bleeders had significantly lower MEA ASPI (median, 14 vs. 27 AUC, p = 0.004) and ADP test values (median, 22 vs. 41 AUC, p = 0.002) as well as TEM values expressed in maximum clot firmness after 30 min (MCF 30) for ExTEM (53 vs. 56 mm, p = 0.005), HepTEM (48 vs. 52 mm, p = 0.003) and FibTEM (8 vs. 11 mm, p < 0.001) test. 24 h CTO inversely correlated with both the MEA (ASPI test: r = -0.236, p = 0.004; ADP test: r = -0.299, p < 0.001), and TEM MCF 30 (ExTEM: r = -0.295, p < 0.001; HepTEM: -0.329, p < 0.001; FibTEM: -0.377, p < 0.001) test values. Our study showed that MEA and TEM are useful methods for prediction of excessive bleeding after ECS. In order to prevent excessive postoperative CTO, hemostatic interventions with timely and targeted blood component therapy according to MEA and TEM results should be considered. PMID:23341179

Petricevic, Mate; Biocina, Bojan; Milicic, Davor; Konosic, Sanja; Svetina, Lucija; Leki?, Ante; Zdilar, Boris; Burcar, Ivan; Milosevic, Milan; Brahimaj, Rifat; Samardzic, Jure; Gasparovic, Hrvoje



Health Technology Assessment on Reprocessing Single-use Catheters for Cardiac Electrophysiology: Results of a Three-years Study  

Microsoft Academic Search

The study aims to define the technical, ethical, juridical and economic issues involved in the assessment of a reprocessing policy for single-use interventional cardiac devices (SUDs). The feasibility of reprocessing was evaluated for cardiac electrophysiology catheters by comparing the chemical, physical and functional properties of new and reprocessed devices. The issue of hygiene was addressed by developing microbiological tests for

F. Tessarolo; M. Disertori; I. Caola; G. M. Guarrera; C. Favaretti; G. Nollo



Sexual problems in cardiac patients: how to assess, when to refer.  


It is increasingly realized that discussing sexuality is an important issue in the holistic care for cardiac patients. In this review article, the conditions of a good assessment of sexual problems are identified such as creating an appropriate environment, ensuring confidentiality, and using appropriate language. Second, we present different styles and approaches that can be used to start the assessment, differing between settings, persons, or disciplines. The PLISSIT (permission, limited information, specific suggestion, and intensive therapy) model can be helpful to initiate discussion about sexuality with the cardiac patient and his/her partner. This model is a stepwise approach using various levels of discussion or treatment. Open-ended question can facilitate discussion about sexual concerns, and validated questionnaires or diaries can be used to assess sexual problems. Patients with sexual concerns and problems should be counseled and/or treated appropriately, and adequate follow-up is needed. Additional training and research are needed to further improve the quality of sexual assessment and counseling in cardiac patients. PMID:20168196

Jaarsma, Tiny; Steinke, Elaine E; Gianotten, Woet L


Exercise-induced ST-segment changes permit prediction of improvement in left ventricular ischemic dysfunction after revascularization: Evaluation with positron emission tomographic measurements of regional myocardial blood flow and cardiac output  

Microsoft Academic Search

Background  Prediction of the recovery of left ventricular (LV) ischemic dysfunction after revascularization is important in patients\\u000a with coronary artery disease (CAD). We investigated whether the improvement in LV ischemic dysfunction after revascularization\\u000a could be predicted preoperatively by exercise-induced ST-segment changes.\\u000a \\u000a \\u000a \\u000a Methods and Results  Regional myocardial blood flow (RMBF) and cardiac output were measured with nitrogen 13-ammonia positron emission tomography\\u000a at rest

Takuya Watanabe; Kenichi Harumi; Tetsuo Michihatas; Osamu Okazaki; Hideyuki Yamanaka; Yasushi Akutsu; Takashi Katagiri



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

PubMed Central

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

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



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

SciTech Connect

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

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



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

Microsoft Academic Search

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

A. Schubert; T. Braun



Functional Cardiac Magnetic Resonance Imaging (MRI) in the Assessment of Myocardial Viability and Perfusion  

PubMed Central

Executive Summary Objective The objective of this health technology policy assessment was to determine the effectiveness safety and cost-effectiveness of using functional cardiac magnetic resonance imaging (MRI) for the assessment of myocardial viability and perfusion in patients with coronary artery disease and left ventricular dysfunction. Results Functional MRI has become increasingly investigated as a noninvasive method for assessing myocardial viability and perfusion. Most patients in the published literature have mild to moderate impaired LV function. It is possible that the severity of LV dysfunction may be an important factor that can alter the diagnostic accuracy of imaging techniques. There is some evidence of comparable or better performance of functional cardiac MRI for the assessment of myocardial viability and perfusion compared with other imaging techniques. However limitations to most of the studies included: Functional cardiac MRI studies that assess myocardial viability and perfusion have had small sample sizes. Some studies assessed myocardial viability/perfusion in patients who had already undergone revascularization, or excluded patients with a prior MI (Schwitter et al., 2001). Lack of explicit detail of patient recruitment. Patients with LVEF >35%. Interstudy variability in post MI imaging time(including acute or chronic MI), when patients with a prior MI were included. Poor interobserver agreement (kappa statistic) in the interpretation of the results. Traditionally, 0.80 is considered “good”. Cardiac MRI measurement of myocardial perfusion to as an adjunct tool to help diagnose CAD (prior to a definitive coronary angiography) has also been examined in some studies, with methodological limitations, yielding comparable results. Many studies examining myocardial viability and perfusion report on the accuracy of imaging methods with limited data on long-term patient outcome and management. Kim et al. (2000) revealed that the transmural extent of hyperenhancement was significantly related to the likelihood of improvement in contractility after revascularization. However, the LVEF in the patient population was 43% prior to revascularization. It is important to know whether the technique has the same degree of accuracy in patients who have more severe LV dysfunction and who would most benefit from an assessment of myocardial viability. “Substantial” viability used as a measure of a patient’s ability to recover after revascularization has not been definitively reported (how much viability is enough?). Patients with severe LV dysfunction are more likely to have mixtures of surviving myocardium, including normal, infarcted, stunned and hibernating myocardium (Cowley et al., 1999). This may lead to a lack of homogeneity of response to testing and to revascularization and contribute to inter- and intra-study differences. There is a need for a large prospective study with adequate follow-up time for patients with CAD and LV dysfunction (LVEF<35%) comparing MRI and an alternate imaging technique. There is some evidence that MRI has comparable sensitivity, specificity and accuracy to PET for determining myocardial viability. However, there is a lack of evidence comparing the accuracy of these two techniques to predict LV function recovery. In addition, some studies refer to PET as the gold standard for the assessment of myocardial viability. Therefore, PET may be an ideal noninvasive imaging comparator to MRI for a prospective study with follow-up. To date, there is a lack of cost-effectiveness analyses (or any economic analyses) of functional cardiac MRI versus an alternate noninvasive imaging method for the assessment of myocardial viability/perfusion. Conclusion There is some evidence that the accuracy of functional cardiac MRI compares favourably with alternate imaging techniques for the assessment of myocardial viability and perfusion. There is insufficient evidence whether functional cardiac MRI can better select which patients [who have CAD and severe LV dysfuncti



Stroke volume variations for assessment of cardiac responsiveness to volume loading in mechanically ventilated patients after cardiac surgery  

Microsoft Academic Search

Objective: We hypothesized that measuring stroke volume variation (SVV) during mechanical ventilation by continuous arterial pulse contour analysis allows the accurate prediction and monitoring of changes in cardiac index (CI) in response to volume administration. Design and setting: Prospective study in an university hospital. Patients: Twenty mechanically ventilated patients following cardiac surgery. Interventions: Volume loading with oxypolygelatin (3.5%) 20 ml

Daniel A. Reuter; Thomas W. Felbinger; Christian Schmidt; Erich Kilger; Oliver Goedje; Peter Lamm; Alwin E. Goetz



Nuclear cardiac imaging for the assessment of myocardial viability  

PubMed Central

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

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



Serial Assessment of Cardiac Function during and following Mitoxantrone Infusion in 30 Consecutive Patients with Multiple Sclerosis  

PubMed Central

Immunosuppressive therapy is an established therapeutic option in patients suffering from multiple sclerosis (MS). In an open nonrandomized study we serially assessed cardiac function in 30 consecutive patients with MS before, during, and after mitoxantrone therapy. Mitoxantrone (12?mg/m2) was administered intravenously at 3-month intervals. Before each infusion, cardiac function was assessed by history taking, resting electrocardiogram, and echocardiography. Whereas no patient experienced clinical signs of heart failure, left ventricular pump function decreased continuously during mitoxantrone therapy and did not recover after cessation. The presented data suggest a dose-dependent and long-lasting toxic cardiac effect of low-dose mitoxantrone therapy in MS.

Franzen, Damian; Haus, Angelika; Hellmich, Martin



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

SciTech Connect

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

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



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

NASA Astrophysics Data System (ADS)

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

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



Current and evolving clinical applications of multidetector cardiac CT in assessment of structural heart disease.  


Multidetector computed tomography (CT) has an established role in the evaluation of selected patients suspected of having coronary disease; however, in addition to coronary assessment, multidetector CT can be used to evaluate numerous noncoronary structures in the same examination. In particular, the use of multidetector CT to provide pulmonary and cardiac venous anatomic information prior to electrophysiology procedures is well established, and its important role in the periprocedural evaluation of patients undergoing percutaneous procedures, such as transcatheter aortic valve replacement and left atrial appendage device occlusion, is being increasingly recognized. Such advances have resulted in multidetector CT being increasingly used as a complementary imaging technique to echocardiography and magnetic resonance imaging for the comprehensive evaluation of cardiac structure and function in particular clinical situations. This review provides an overview of the noncoronary cardiac structures that can be evaluated with multidetector CT, and outlines the established appropriate clinical uses of multidetector CT in the assessment of structural heart disease, as well as evolving periprocedural clinical applications. PMID:23525715

Nasis, Arthur; Mottram, Philip M; Cameron, James D; Seneviratne, Sujith K



[Assessment of outcome in treatment of cardiac shock after myocardial infarction with intravenous streptokinase].  


In 1986 a prospective randomized study coordinated by the Institute of Cardiology in Warsaw was started in 10 teaching cardiology hospitals in Poland for assessment of the results of treatment with intravenous streptokinase infusion in acute myocardial infarction. The studied population comprised 927 patients admitted to intensive treatment units within 6 hours after the onset of infarction pain. For the groups treated with streptokinase or heparin 752 patients were selected at random. In 175 cases the administration of streptokinase was contraindicated. These patients received conventional treatment and served as controls. The age of the patients was from 38 to 70 years, mean age 57.6 +/- 9.3 years. In 105 out of 927 cases cardiac shock was diagnosed. In the groups of early shock during hospitalization the death rate was 82%. No statistically significant difference was found in the death rates between patients with cardiac shock treated with heparin or with streptokinase. PMID:8351236

Sadowski, Z; Srzednicki, M; Poprawski, K; Kalici?ski, A; Stolarczyk, L; Nartowicz, E; Kuch, J; Mazurek, S; Opolski, G; Wójcik, J



Cardiac Resynchronization Therapy and Implantable Cardiac Defibrillators in Left Ventricular Systolic Dysfunction. Evidence Report/Technology Assessment Number 152.  

National Technical Information Service (NTIS)

Cardiac resynchronization therapy (CRT) refers to atrial-synchronized biventricular pacing (i.e., pacing the right atrium, right ventricle, and left ventricle). CRT improves the electrical dyssynchrony found in many patients with heart failure (HF) and th...

B. Vandermeer C. Friesen C. Spooner D. M. Dryden F. A. McAlister J. Ezekowitz N. Hooton



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

PubMed Central

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




PubMed Central

The world’s first magnetoencephalography (MEG) system specifically designed for fetal and newborn assessment has been installed at the University of Arkansas for Medical Sciences. This non-invasive system called SARA (Squid Array for Reproductive Assessment) consists of 151 primary superconducting sensors which detect biomagnetic fields from the human body. Since the installation of SARA, significant progress has been made toward the ultimate goal of developing a clinical neurological assessment tool for the developing fetus. Using appropriate analysis techniques, cardiac and brain signals are recorded and studied to gain new understanding of fetal maturation. It is clear from our investigations that a combination of assessment protocols including both fetal heart and brain activity is necessary for the development of a comprehensive new method of fetal neurological testing. We plan to implement such a test protocol for fetuses at high-risk for neurological impairment due to certain maternal risk factors and/or fetal diagnostic findings.

Lowery, Curtis L.; Govindan, R. B.; Murphy, Pamela; Eswaran, Hari



A novel cardiac MR chamber volume model for mechanical dyssynchrony assessment  

NASA Astrophysics Data System (ADS)

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

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



[Positron emission tomography (PET): a useful tool for the assessment of cardiac metabolism].  


Under normal conditions, myocardial metabolism is based on the oxidation of fatty acids and in a lesser extent carbohydrates. Cardiac function depends upon an adequate supplement of adenosine triphosphate (ATP) by these substrates. However, the main source of energy is susceptible to change upon a various physiologic (exercise) as well as pathologic (ischemia-reperfusion) conditions. Recently, carnitine has gained attention as a modulator of fatty acids and carbohydrates metabolism by means of modifying intramitochondrial Acetyl-CoA/CoA ratio. Disturbances in fatty acids and carbohydrates metabolism in the myocardium have been associated with cardiovascular diseases (chronic ischemic disease, ventricular hypertrophy and dilated cardiomyopathy). The evaluation of cardiac metabolism attains great value regarding diagnosis, treatment and prognosis of these diseases. Currently, positron emission tomography (PET) is one of the preferred methods to evaluate cardiac energy metabolism in clinical practice. In PET images the tracers most commonly used are 11C-palmitate, 11C-acetate y 18Fluoro-2-deoxyglucose (FDG), the first two are employed to assess fatty acids oxidation and FDG is used to evaluate carbohydrates metabolism. PMID:15559875

Alexánderson, Erick; Gómez-Martín, Diana; Benito, Israel; Ruíz-Ramírez, Leonel; Ricalde, Alejandro; Meave, Aloha


The Efficacy of Cardiac Findings in Assessing the Outcome in Preterms with Bronchopulmonary Dysplasia.  


OBJECTIVES: To evaluate if cardiac dysfunctions are important in assessing the outcome in newborns with Bronchopulmonary Dysplasia (BPD), by evaluating cardiac functions with N-terminal prohormone of brain natriüretic peptide (NT-proBNP) levels, M-mode and tissue doppler echocardiography at 6-12 mo of age. METHODS: Twenty eight patients were retrospectively classified as mild, moderate and severe according to the diagnostic criterias for BPD. All cases were assessed with standard M-mode, tissue doppler echocardiography and NT-proBNP levels. Control group consisted of 28 healthy infants, having similar postnatal ages as patients and were assessed with standard M-mode and tissue doppler echocardiography. RESULTS: The age of patients with BPD was 9.8?±?2.3 mo and control group was 9.5?±?2.6 mo. There was no significant difference between the postnatal ages of two groups (p?>?0.05). Neither pulmonary hypertension nor pulmonary/tricuspid regurgitation was detected. The M-mode echocardiography measurements did not differ between patients and control group (p?>?0.05). Tissue doppler echocardiography, tricuspid valve medial segment early diastolic myocardial relaxation velocity (TME') measurements of patients were found significantly lower, peak transtricuspid filling velocity in the early diastole (TE)/TME' ratios and isovolumetric relaxation time (IVRT) measurements were found significantly higher than control group (p??0.05). CONCLUSIONS: This is the first study evaluating cardiac findings in patients with BPD by tissue doppler echocardiography and NT-proBNP at the same time. On the basis of cardiac evaluations, tissue doppler echocardiography measurements were found as significant and specific for the early assessment of right ventricular diastolic disfunctions. PMID:23504480

Akcan, Abdullah Bar??; Kardelen, F?rat; Oygucu, Seyhan Eri?ir; Kocaba?, Abdullah; Ozel, Deniz; Akba?, Halide; Oygür, Nihal



High-sensitivity troponin T and C-reactive protein to identify patients without cardiac structural and functional abnormalities as assessed by cardiac CT and SPECT imaging: can biomarkers predict cardiac health?  


While high-sensitivity troponin-T (hsTnT) and C-reactive protein (hsCRP) are associated with structural heart disease, we thought to determine whether biomarkers can predict which heart is healthy based on multimodality imaging. Patients from the emergency department with acute chest pain suggestive of acute coronary syndrome undergoing contrast enhanced cardiac CT and stress single photon emission computed tomography (SPECT) myocardial perfusion imaging were included. HsTnT and hsCRP were assessed at time of CT. Imaging data were assessed for coronary atherosclerosis, left ventricular hypertrophy/dysfunction and myocardial perfusion abnormalities. Patients were stratified into those with or without any cardiac findings, who were considered as cardiac healthy. For biomarkers, low cut-off corresponding to good specificity and high cut-off corresponding to good sensitivity for cardiac health were derived. Among 117 patients (52 years, 55 % male), 42 (36 %) were cardiac healthy based on cardiac CT and SPECT imaging. These patients had significantly lower hsTnT and hsCRP levels as compared to those with functional or structural abnormalities (3.58 vs. 5.63 ng/L, p = 0.002; 0.82 vs. 1.93 mg/L, p = 0.0005; respectively). Patients with both low hsTnT (<3.00 ng/L) and hsCRP (<0.45 mg/L) had a probability of 85 % for being cardiac healthy. In contrast, patients with high hsTnT (>7.00 ng/L) and hsCRP (>2.00 mg/L) had 8 % probability for being cardiac healthy. Discriminative capacity of a dual-biomarker strategy was significantly improved as compared to hsTnT or hsCRP alone or to Framingham Risk score (AUC: 0.781 vs. 0.691; vs. 0.678; vs. 0.649; all p ? 0.02, respectively). A dual-biomarker strategy of hsTnT and hsCRP is highly discriminative for patients with normal cardiac structure and function and provides incremental value beyond the Framingham risk score. PMID:23274882

Schlett, Christopher L; Truong, Quynh A; Ahmed, Waleed; Blankstein, Ron; Ferencik, Maros; Uthamalingam, Shanmugam; Bamberg, Fabian; Koenig, Wolfgang; Januzzi, James L; Hoffmann, Udo



An adaptive regional input-output model and its application to the assessment of the economic cost of Katrina.  


This article proposes a new modeling framework to investigate the consequences of natural disasters and the following reconstruction phase. Based on input-output tables, its originalities are (1) the taking into account of sector production capacities and of both forward and backward propagations within the economic system; and (2) the introduction of adaptive behaviors. The model is used to simulate the response of the economy of Louisiana to the landfall of Katrina. The model is found consistent with available data, and provides two important insights. First, economic processes exacerbate direct losses, and total costs are estimated at $149 billion, for direct losses equal to $107 billion. When exploring the impacts of other possible disasters, it is found that total losses due to a disaster affecting Louisiana increase nonlinearly with respect to direct losses when the latter exceed $50 billion. When direct losses exceed $200 billion, for instance, total losses are twice as large as direct losses. For risk management, therefore, direct losses are insufficient measures of disaster consequences. Second, positive and negative backward propagation mechanisms are essential for the assessment of disaster consequences, and the taking into account of production capacities is necessary to avoid overestimating the positive effects of reconstruction. A systematic sensitivity analysis shows that, among all parameters, the overproduction capacity in the construction sector and the adaptation characteristic time are the most important. PMID:18643833

Hallegatte, Stéphane



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

PubMed Central

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

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



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

PubMed Central

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

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



The cyclooxygenase-2 product prostaglandin E 2 modulates cardiac contractile function in adult rat ventricular cardiomyocytes  

Microsoft Academic Search

Prostaglandin E2 (PGE2), a product of the cyclooxygenase-2 pathway, has been shown to increase cardiac output and modulate cardiac contractile function. However, whether the cardiac contractile response of PGE2 is due to its action on single ventricular myocytes has not been elucidated. To assess the mechanical effect of PGE2 at the cellular level, adult rat ventricular myocytes were isolated and

Aaron L. Klein; Loren E. Wold; Jun Ren



Cardiac anatomy, function and metabolism in elite cyclists assessed by magnetic resonance imaging and spectroscopy.  


We investigated whether left ventricular hypertrophy in elite cyclists is associated with functional changes or abnormal energy metabolism. Left ventricular hypertrophy is a powerful risk factor for sudden cardiac death with different prognostic significance among the various geometric forms. Cyclists may have a combination of mixed eccentric and concentric hypertrophy. Magnetic resonance imaging was used to define left ventricular mass, geometry and function. Thirteen highly trained male cyclists and 12 healthy controls were investigated. Proton-decoupled phosphorus-31 cardiac spectroscopy was performed to assess parameters of myocardial high-energy phosphate metabolism. Left ventricular mass and end-diastolic volumes normalized for body surface area were significantly higher in cyclists (124.1 +/- 9.4 g.m-2 and 106.2 +/- 11.4 ml.m-2, respectively) than in controls (85.9 +/- 9.3 g.m-2 and 79.1 +/- 11.6 ml.m-2, respectively), (both P < 0.0001). The left ventricular mass to end-diastolic volume ratio, as a parameter of left ventricular geometry, was not significantly increased in cyclists compared to controls. Resting left ventricular ejection fraction, cardiac index, and systolic wall stress in cyclists did not differ significantly from those of controls. The phosphocreatine to adenosine triphosphate ratio was not significantly different between cyclists and controls (2.2 +/- 0.34 vs 2.2 +/- 0.17, ns). Cyclists show prominent left ventricular hypertrophy with normal geometry. The finding that the hypertrophic hearts of the cyclists had normal left ventricular function and a normal phosphocreatine to adenosine triphosphate ratio suggests that sport-induced left ventricular hypertrophy is a physiological adaptation rather than a pathophysiological response. PMID:8869870

Pluim, B M; Chin, J C; De Roos, A; Doornbos, J; Siebelink, H M; Van der Laarse, A; Vliegen, H W; Lamerichs, R M; Bruschke, A V; Van der Wall, E E



Assessment of updated CAD without a new reader study: effect of calibration of computer output on the computer-aided reader performance in CADx  

Microsoft Academic Search

It is very resource-demanding to assess each new version of a CAD system through a new reader study. We conjecture that the aided reader performance on a new version can be predicted by using certain characteristics of the computer output and the reader study conducted when the CAD system was initially introduced. This would likely reduce the need for additional

Weijie Chen; Nicholas Petrick; Berkman Sahiner



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

PubMed Central

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

Molnar, Frank J.; Simpson, Christopher S.



Assessment of Outputs from Smith-Root Model5.0 GPP and Model7.5 GPP Electrofishers  

Microsoft Academic Search

We evaluated the outputs from eight Smith-Root electrofishers (two factory-rigged model-5.0 GPP boats, four biologist-rigged model-5.0 GPP boats, and two biologist-rigged model-7.5 GPP boats), using an oscilloscope to determine the actual waveforms (voltage as a function of time), current, and power produced for various settings. Differences were found in average power outputs among the six model-5.0 GPP electrofishing boats. In

Kevin L. Pope; Brian E. Van Zee; Michael C. Mayo; Mohammed Rahman



Cardiac magnetic resonance for the assessment of myocardial viability: from pathophysiology to clinical practice.  


Cardiac magnetic resonance (CMR) is commonly applied for the assessment of myocardial viability in patients with ischemic ventricular dysfunction, and it holds potential advantages over more traditional imaging modalities, including single-photon emission computed tomography (SPECT) and dobutamine stress echocardiography (DSE). CMR-based techniques for viability assessment include the evaluation of transmural extent of the scar using late gadolinium enhancement (LGE) images, the evaluation of end-diastolic wall thickness from resting cine images and the study of inotropic reserve during low-dose dobutamine infusion. During the past decade, the diffusion of the use of CMR for viability assessment confirmed the clinical strengths of this modality and, at the same time, helped to use old techniques with an increased level of awareness. With LGE CMR, both viable and nonviable dysfunctional myocardium can be visualized in a single image, allowing a direct quantification of the amount of regional viability, with a significant impact on the estimation of chance for recovery. As well, studies with CMR applied in the setting of ischemic heart disease allowed a better understanding of the best way to apply and interpret other tests for viability evaluation. For instance, it has been demonstrated that the transmural extension of the scar may influence the level of concordance between SPECT and DSE in assessing myocardial viability. The transmural extent of scar on LGE CMR also correlates with the timing of postrevascularization recovery of systolic function, with significant impact on the diagnostic accuracy of any applied imaging modality. PMID:23756415

Dellegrottaglie, Santo; Guarini, Pasquale; Savarese, Gianluigi; Gambardella, Francesco; Iudice, Francesco Lo; Cirillo, Annapaola; Vitagliano, Alice; Formisano, Tiziana; Pellegrino, Angela M; Bossone, Eduardo; Perrone-Filardi, Pasquale



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

PubMed Central

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

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



Cardiac Output Responses During Exercise in Volume-Expanded Heart Transplant Recipients 1 1 This work was supported by National Institutes of Health Clinical Research Center Grant RR00082 and Dr. Braith was supported by a NIH National Research Service Award (HL08777), Bethesda, Maryland  

Microsoft Academic Search

The mechanisms responsible for immediate adjustments in cardiac output at onset of exercise, in the absence of neural drive, are not well defined in heart transplant (HT) recipients. Seven male HT recipients (mean ± SD 57 ± 6 years) and 7 age-matched sedentary normal control subjects (mean age 57 ± 5 years) performed constant load cycle exercise at 40% of

Randy W Braith; Mary B Plunkett; Roger M Mills



Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.  


The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises. PMID:23327555

Sugisaki, Norihide; Okada, Junichi; Kanehisa, Hiroaki



Sequelae of Acute Myocardial Infarction Regarding Cardiac Structure and Function and Their Prognostic Significance as Assessed by Magnetic Resonance Imaging  

Microsoft Academic Search

Aims Because of its high spatial resolution and tissue contrast, magnetic resonance imaging (MRI) was used to assess cardiac structure and function in a large population of patients with acute myocardial infarction (AMI). Methods and results One hundred and ten patients were studied by MRI 6.1 + 2.2 days after AMI. Infarct size (IS), persistent microvascular obstruction (PMO), left and

Vinzenz Hombach; Olaf Grebe; Nico Merkle



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

PubMed Central

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

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



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


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

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



Combining input-output analysis and micro-simulation to assess the effects of carbon taxation on Spanish households  

Microsoft Academic Search

This paper explores the effects of a tax levied on Spanish energy-related CO2 emissions. After justifying the relevance of carbon taxation in the Spanish context, we consider the introduction of a product (fossil-fuel) tax with a rate obtained through the ‘actual damage cost’ method. Our empirical analysis proceeds in two stages. First, we employ an input-output demand model to calculate

Xavier Labandeira; José M. Labeaga



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

Microsoft Academic Search

BACKGROUND: Cardiac rehabilitation programs offer effective means to prevent recurrence of a cardiac event, but poor uptake of current programs have been reported globally. Home based models are considered as a feasible alternative to avoid various barriers related to care centre based programs. This paper sets out the study design for a clinical trial seeking to test the hypothesis that

Darren L Walters; Antti Sarela; Anita Fairfull; Kylie Neighbour; Cherie Cowen; Belinda Stephens; Tom Sellwood; Bernadette Sellwood; Marie Steer; Michelle Aust; Rebecca Francis; Chi-Keung Lee; Sheridan Hoffman; Gavin Brealey; Mohan Karunanithi



Assessment of regional myocardial strain using cardiac elastography: distinguishing infarcted from non-infarcted myocardium  

Microsoft Academic Search

Estimation of the regional mechanical properties of the cardiac muscle has been shown to play a crucial role in the detection of cardiovascular disease. Current echocardiography-based cardiac motion estimation techniques, such as Doppler Myocardial Imaging (DMI), are limited due to angle dependence. By contrast, elastography, a method designed and used for the detection of tumors, measures displacement and strain by

E. E. Konofagou; T. Harrigan; S. Solomon



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


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

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



Delayed contrast-enhanced MRI: use in myocardial viability assessment and other cardiac pathology.  


As in other organs, tissue characterization is important for many cardiac diseases. For example, in ischemic heart disease, differentiation between reversibly and irreversibly damaged myocardium in patients with a prior myocardial infarction is crucial in determining disease severity, functional recovery and patient outcome. With the recent advent of the single inversion-recovery contrast-enhanced magnetic resonance imaging (MRI) sequence (delayed contrast-enhanced MRI), contrast between normal and abnormal tissues could be significantly enhanced compared with the conventional cardiac MRI sequences, enabling even subtle abnormalities to be visualized. Together with other advances in cardiac MRI (e.g. functional imaging, coronary artery imaging), MRI has become one of the preferred non-invasive modalities to study cardiac diseases. In this paper an overview of the versatility of delayed contrast-enhanced MRI for investigating cardiac diseases is given. PMID:15801058

Bogaert, Jan; Dymarkowski, Steven



Is Magnetic Resonance Imaging the 'Reference Standard' for Cardiac Functional Assessment? Factors Influencing Measurement of Left Ventricular Mass and Volumes  

Microsoft Academic Search

Purpose\\u000a   MRI is considered\\u000a reference standard for the\\u000a assessment of left ventricular (LV)\\u000a volume and mass measurements.\\u000a There are few accepted guidelines\\u000a for uniform assessment of cardiac\\u000a function with MRI. We sought to\\u000a investigate different confounding\\u000a factors influencing LV measurement\\u000a results.\\u000a \\u000a \\u000a \\u000a \\u000a Material and Methods\\u000a   In 60 diabetic type-II patients\\u000a (group A) we compared intra-\\/inter-reader variability of MRI for\\u000a cardiac function

Henning Steen; Khurram Nasir; Ellen Flynn; Iman El-Shehaby; Shenghan Lai; Hugo A. Katus; David Bluemcke; João A. C. Lima



Assessment of Cardiac Structure and Left Atrial Appendage Functions in Primary Antiphospholipid Syndrome A Transesophageal Echocardiographic Study  

Microsoft Academic Search

Background and Purpose—Although thromboembolic events are the major complication of primary antiphospholipid syndrome (PAPS), cardiac involvement is commonly present. Left atrial appendage (LAA) is recognized as an important source for thrombus formation and thromboembolism. The purpose of the study was to assess the structure and function of LAA with transesophageal echocardiography (TEE) in PAPS patients. Methods—Thirty-one PAPS patients (22 women,

Dogan Erdogan; M. Taner Goren; Reyhan Diz-Kucukkaya; Murat Inanc


Development of a Pacemaker Monitor with Cardiac Simulator.  

National Technical Information Service (NTIS)

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

T. O. Steiner



Restored cardiac conditions and left ventricular function after parathyroidectomy in a hemodialysis patient. Parathyroidectomy improves cardiac fatty acid metabolism assessed by 123I-BMIPP.  


A 62 year-old female hemodialysis patient underwent parathyroidectomy to treat secondary hyperparathyroidism. On the preoperative assessment, the plasma levels of parathyroid hormone (PTH) and B-type natriuretic peptide (BNP) were elevated. Echocardiography showed reduced left ventricular (LV) contraction. Myocardial iodine-123-15-(p-iodophenyl)-3-(R,S) methylpentadecanoic acid ((123)I-BMIPP) scintigraphy showed moderately reduced tracer uptake in the postero-inferior area on single-photon emission computed tomography and decreased washout on the planar images. After parathyroidectomy, the plasma levels of PTH and BNP decreased, followed by improvement in LV contraction. Myocardial (123)I-BMIPP scintigraphy revealed that the washout on planar images had increased, which suggests that myocardial (123)I-BMIPP scintigraphy is useful for estimating the effect of parathyroidectomy on cardiac function. PMID:19179778

Nanasato, Mamoru; Goto, Norihiko; Isobe, Satoshi; Unno, Kazumasa; Hirayama, Haruo; Sato, Tetsuhiko; Matsuoka, Susumu; Nagasaka, Takaharu; Tominaga, Yoshihiro; Uchida, Kazuharu; Murohara, Toyoaki



Experimental study of afterload-reducing therapy: the effects of the reduction of systemic vascular resistance on cardiac output, aortic pressure and coronary circulation in isolated, ejecting canine hearts.  


The relationship between cardiac output (CO) and peripheral resistance (Rp) was examined under the following conditions for coronary perfusion: constant coronary flow perfusion; perfusion with a pressure equal to mean aortic pressure (AoP perfusion); and perfusion with a pressure equal to the mean AoP - 30 mm Hg (AoP - 30 mm Hg perfusion). We also examined the coronary pressure-flow relationship. For these studies, we used paced, isolated, ejecting canine hearts, which were loaded by a hydraulic system that simulated the input impedance of a dog's systemic arterial tree. The CO in the constant coronary flow perfusion continued to increase with the reduction of Rp. The CO in the AoP perfusion became maximal at a slightly subphysiologic Rp, or at an average mean AoP of 65 mm Hg. This mean AoP was closely associated with the lower limit of the autoregulation of coronary blood flow. In the AoP - 30 mm Hg perfusion, the mean AoP at which CO became maximal was 72 mm Hg and the corresponding coronary perfusion pressure appeared to be lower than the lower limit of the perfusion pressure range for coronary flow autoregulation. The Rp value at that point was slightly higher than the physiologic range. We conclude that when coronary perfusion pressure changes with mean AoP, and when left ventricular end-diastolic pressure is fixed, there is a clear optimal Rp at which CO becomes maximal, and this optimal Rp is higher if coronary perfusion pressure is biased from mean AoP to a significant degree. PMID:7261281

Isoyama, S; Maruyama, Y; Koiwa, Y; Ishide, N; Kitaoka, S; Tamaki, K; Sato, S; Shimizu, Y; Ino-Oka, E; Takishima, T



Monitoring during paediatric cardiac anaesthesia  

Microsoft Academic Search

Monitoring of paediatric anaesthesia has become increasingly more complex in recent years and this is particulary true of\\u000a cardiac anaesthesia. The purpose of this review is to give a comprehensive update of published material related to both routine\\u000a and specialized cardiac monitoring. Routine monitoring can be particularly affected by the alterations of cardiac rhythm,\\u000a blood flow, cardiac output and oxygenation

Jonathan P. Purday



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

Microsoft Academic Search

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

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


Delirium in cardiac surgery : a study on risk-assessment and long-term consequenses  

Microsoft Academic Search

BACKGROUND:\\u000aDelirium or acute confusion is a temporary mental disorder, which occurs frequently among hospitalized elderly patients. Patients who undergo cardiac surgery have an increased risk of developing delirium. Delirium is associated with many negative consequences. Therefore, prevention or early recognition of delirium is essential. -\\u000a\\u000aMAIN AIMS:\\u000a?\\u0009measure incidence delirium and duration of delirium episode after cardiac surgery

Sandra Koster



Cardiac syncope.  


Clinicians who diagnose and manage epilepsy frequently encounter diagnoses of a nonneurological nature, particularly when assessing patients with transient loss of consciousness (T-LOC). Among these, and perhaps the most important, is cardiac syncope. As a group, patients with cardiac syncope have the highest likelihood of subsequent sudden death, and yet, unlike sudden unexpected death in epilepsy (SUDEP) for example, it is the norm for these tragic occurrences to be both easily predictable and preventable. In the 12 months following initial presentation with cardiac syncope, sudden death has been found to be 6 times more common than in those with noncardiac syncope (N Engl J Med 309, 1983, 197). In short, for every patient seen with T-LOC, two fundamental aims of the consultation are to assess the likelihood of cardiac syncope as the cause, and to estimate the risk of future sudden death for the individual. This article aims to outline for the noncardiologist how to recognize cardiac syncope, how to tell it apart from more benign cardiovascular forms of syncope as well as from seizures and epilepsy, and what can be done to predict and prevent sudden death in these patients. This is achieved through the assessment triad of a clinical history and examination, risk stratification, and 12-lead electrocardiography (ECG). PMID:23153208

Anderson, Joseph; O'Callaghan, Peter



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

PubMed Central

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

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



Cost and effectiveness assessment of cardiac rehabilitation for dialysis patients following coronary bypass  

PubMed Central

Dialysis patients have a high risk of cardiovascular disease. In the general population, cardiac rehabilitation is recommended as a standard component of care and is covered by Medicare for patients who have undergone coronary artery bypass grafting (CABG). Previous investigation demonstrated survival benefit of cardiac rehabilitation in dialysis patients. This study investigated its impact on Medicare expenditure and its cost effectiveness. A cohort of 4,324 end-stage renal disease (ESRD) patients who initiated chronic hemodialysis and underwent CABG between 1998 and 2004 was selected from the United States Renal Data System. Cardiac rehabilitation was defined by Current Procedural Terminology codes for monitored and nonmonitored exercise in Medicare claims data. Medicare expenditure included inpatient and outpatient claims with cost adjusted to 1998 dollars. At 42 months of follow-up after a 6-month entry period following CABG hospitalization discharge, cardiac rehabilitation at baseline was associated with higher cumulative Medicare expenditure, incurring a statistically nonsignificant increment of $2,904 (95% CI: ?7,028, 11,940). During the same period, cardiac rehabilitation was significantly associated with longer cumulative lifetime, having an incremental benefit of 76 days (95% CI: 22, 129). The incremental cost-effectiveness ratio was $13,887 per year of life saved, suggesting that cardiac rehabilitation is highly cost-effective in ESRD patients following CABG.

Huang, Yijian; Zhang, Rebecca; Culler, Steven; Kutner, Nancy



Assessment of PDA shunt and systemic blood flow in newborns using cardiac MRI.  


Patent ductus arteriosus (PDA) remains common in preterm newborns, but uncertainty over optimal management is perpetuated by clinicians' inability to quantify its true haemodynamic impact. Our aim was to develop a technique to quantify ductal shunt volume and the effect of PDA on systemic blood flow volume in neonates. Phase contrast MRI sequences were optimized to quantify left ventricular output (LVO) and blood flow in the distal superior vena cava (SVC) (below the azygos vein insertion), descending aorta (DAo) and azygos vein. Total systemic flow was measured as SVC + DAo-azygos flow. Echo measures were included and correlated to shunt volumes. 75 infants with median (range) corrected gestation 33(+6) (26(+4) -38(+6) ) weeks were assessed. PDA was present in 15. In 60 infants without PDA, LVO matched total systemic flow (mean difference 2.06 ml/kg/min, repeatability index 13.2%). In PDA infants, ductal shunt volume was 7.9-74.2% of LVO. Multiple linear regression analysis correcting for gestational age showed that there was a significant association between ductal shunt volume and decreased upper and lower body flow (p = 0.01 and p < 0.001). However, upper body blood flow volumes were within the control group 95% confidence limits in all 15 infants with PDA, and lower body flow volumes within the control group limits in 12 infants with PDA. Echocardiographic assessment of reversed diastolic flow in the descending aorta had the strongest correlation with ductal shunt volume. We have demonstrated that quantification of shunt volume is feasible in neonates. In the presence of high volume ductal shunting the upper and lower body flow volume are somewhat reduced, but levels remain within or close to the normal range for preterm infants. PMID:23412748

Broadhouse, Kathryn M; Price, Anthony N; Durighel, Giuliana; Cox, David J; Finnemore, Anna E; Edwards, A David; Hajnal, Joseph V; Groves, Alan M



Heterogeneity and time course of improvement in cardiac function after cardioversion of chronic atrial fibrillation: assessment of serial echocardiographic indices.  

PubMed Central

OBJECTIVE--To assess the clinical characteristics of patients in whom cardiac function improved after cardioversion of atrial fibrillation and the time course of the improvement. DESIGN--A prospective serial study of echocardiograms recorded before cardioversion and one day, seven days, one month, and three months after cardioversion. SETTING--Echocardiography laboratory of a university hospital. PATIENTS--23 patients with chronic atrial fibrillation in whom cardioversion was successful. MAIN OUTCOME MEASURES--M mode indices of the left ventricular wall motion and pulsed Doppler indices of the left ventricular inflow. RESULTS--Three months after cardioversion percentage fractional shortening had increased by more than 5% in 14 patients (improved group) and by less than 5% in nine patients (non-improved group). Those in whom cardiac function improved had significantly higher heart rates and a greater reduction in ventricular filling during atrial fibrillation and a more prominent atrial filling wave three months after cardioversion than those patients in the non-improved group. Over the three months of follow up the mean (1SD) percentage fractional shortening increased from 22 (3)% to 30 (4)% in the improved group and in this group heart rate fell one day after cardioversion. A month after cardioversion the percentage fractional shortening had increased to 35 (5)% and the atrial systolic contribution to left ventricular filling increased from 30 (9)% on day 1 to 47 (12)%. CONCLUSIONS--Cardioversion improved cardiac function in patients with tachycardia and reduced ventricular filling during atrial fibrillation. Because both an immediate reduction of heart rate and a delayed recovery of atrial booster pump function played an important part in the improvement of cardiac function the long-term effects of cardioversion should be assessed at least a month after cardioversion. Images

Shite, J; Yokota, Y; Yokoyama, M



Preoperative cardiac risk assessment for noncardiac surgery: defining costs and risks.  


Cardiac risk stratification before noncardiac surgery remains important. Two major areas have been emphaized, namely, cost-effective risk stratification and enhanced identification of high risk populations. Recent studies have highlighted the lack of quality and affordable medical consultation. The indications for resting preoperative echocardiography merit streamlining, given recent data that failed to demonstrate tangible benefit. Further more, noninvasive cardiac stress testing is expensive and unnecessary in low risk patients. Perioperative troponin determination significantly improves the detection of myocardial infarction, facilitating its early management. The revised cardiac risk index is a standard tool for risk stratification, despite multiple limitations. The first approach has been tore calibrate the traditional risk index to specific high-risk surgical subgroups. The second approach has been to develop new cardiac risk models with more power. Both approaches have yielded risk calculators that out perform the traditional risk model. Furthermore, this latest generation of risk models is available as online calculators that can be accessed at the bedside. Further clinical trials are indicated to test the validity, clinical utility, and cost-effectiveness of these novel risk calculators. It is likely that these powerful instruments will refine the indications for specialized cardiac testing, offering multiple opportunities to reduce perioperative risk and cost simultaneously. PMID:23620898

Augoustides, John G T; Neuman, Mark D; Al-Ghofaily, Lourdes; Silvay, George



A nonparametric assessment of the relative output of INAA and PIXE on joint determinands in environmental samples (atmospheric biomonitors)  

NASA Astrophysics Data System (ADS)

Other than their inherent accuracy, analytical robustness and nondestructive features, instrumental neutron activation analysis (INAA) and particle-induced X-ray emission (PIXE) are both multi-elemental techniques that complement - and partially overlap - each other with respect to a vast majority of elements of interest in environmental studies and life sciences at large. Analytical accuracy notwithstanding, INAA and PIXE ask for different sample-preparation procedures and rely on dissimilar energy-related profiles, which can lead to some divergence in their operational outputs. Especially interesting are the elements determined by either technique, in that they can provide what one might call an index of intrinsic reliability as to an elemental pool. This paper presents an evaluation of the relative performance of INAA and PIXE on measurements in atmospheric biomonitors, namely epiphytic lichens of the Parmelia genus. The study is based upon 4 elements - Fe, Mn, Rb (customary crustal references) and K (an indicator of physiological status) - in lichen samples from 58 sites in mainland Portugal. Distribution-free statistics - rank-order correlations and enhanced-sign tests - were used for checking the degree of association between concentration patterns (variables) and any significant differences between individual values (variates), respectively. The results show that (i) for all elements, the area-wide patterns by either technique display similar trends; and (ii) for all elements but rubidium, no statistically sound evidence for relative bias - consistently higher or lower values by one technique - could be found. As far as this investigation goes, the techniques may be used interchangeably for determining Fe, K and Mn in Parmelia spp. samples.

Pacheco, Adriano M. G.; Freitas, Maria Do Carmo; Ventura, Márcia G.




EPA Science Inventory

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


Role of cardiac MRI in evaluating patients with Anderson-Fabry disease: assessing cardiac effects of long-term enzyme replacement therapy  

Microsoft Academic Search

Purpose  Anderson-Fabry disease is a multisystemic disorder of lipid metabolism secondary to X-chromosome alterations and is frequently\\u000a associated with cardiac manifestations such as left ventricular (LV) hypertrophy, gradually leading to an alteration in cardiac\\u000a performance. The purpose of this study was to monitor, using magnetic resonance imaging (MRI), any changes produced by enzyme\\u000a replacement therapy with agalsidase beta at the cardiac

G. Messalli; M. Imbriaco; G. Avitabile; R. Russo; D. Iodice; L. Spinelli; S. Dellegrottaglie; F. Cademartiri; M. Salvatore; A. Pisani


Feasibility of aortic valve assessment with low dose prospectively triggered adaptive systolic (PTAS) cardiac computed tomography angiography  

PubMed Central

Background Cardiac computed tomography angiography (CTA) is feasible for aortic valve evaluation, but retrospective gated protocols required high radiation doses for aortic valve assessment. A prospectively triggered adaptive systolic (PTAS) cardiac CT protocol was recently described in arrhythmia using second-generation dual-source CT. In this study, we sought to evaluate the feasibility of PTAS CTA to assess the aortic valve at a low radiation dose. Findings A retrospective cohort of 29 consecutive patients whom underwent PTAS protocols for clinical indications other than aortic valve assessment and whom also received echocardiography within 2 months of CT, was identified. Images were reviewed for aortic valve morphology (tricuspid/bicuspid/prosthetic) and stenosis (AS) by experienced blinded readers. Accuracy versus echocardiography and radiation doses were assessed. All PTAS coronary CTAs were clinically diagnostic with 0 un-evaluable coronary segments. The accuracy of PTAS for aortic valve morphology was 92.6%, and for exclusion of severe AS was 93.1%. Two exams were un-evaluable for the aortic valve due to inadequate number of phases archived for interpretation. Total radiation dose was a median of 2.8 mSv (interquartile range 1.4–4.4 mSv). Conclusions PTAS CTA protocols using second-generation dual-source CT for aortic valve evaluation are feasible at low doses. This protocol should be investigated further in larger cohorts.



Impaired cardiac function in chronic fatigue syndrome measured using magnetic resonance cardiac tagging  

PubMed Central

Objectives Impaired cardiac function has been confirmed in patients with chronic fatigue syndrome (CFS). Magnetic resonance cardiac tagging is a novel technique that assesses myocardial wall function in vivo. We hypothesized that patients with CFS may have impaired development and release of myocardial torsion and strain. Methods Cardiac morphology and function were assessed using magnetic resonance imaging and cardiac tagging methodology in 12 CFS patients (Fukuda) and 10 matched controls. Results Compared to controls, the CFS group had substantially reduced left ventricular mass (reduced by 23%), end-diastolic volume (30%), stroke volume (29%) and cardiac output (25%). Residual torsion at 150% of the end-systolic time was found to be significantly higher in the patients with CFS (5.3 ± 1.6°) compared to the control group (1.7 ± 0.7°, P = 0.0001). End-diastolic volume index correlated negatively with both torsion-to-endocardial-strain ratio (TSR) (r = ?0.65, P = 0.02) and the residual torsion at 150% end-systolic time (r = ?0.76, P = 0.004), so decreased end-diastolic volume is associated with raised TSR and torsion persisting longer into diastole. Reduced end-diastolic volume index also correlated significantly with increased radial thickening (r = ?0.65, P = 0.03) and impaired diastolic function represented by the ratio of early to late ventricular filling velocity (E/A ratio, r = 0.71, P = 0.009) and early filling percentage (r = 0.73, P = 0.008). Conclusion Patients with CFS have markedly reduced cardiac mass and blood pool volumes, particularly end-diastolic volume: this results in significant impairments in stroke volume and cardiac output compared to controls. The CFS group appeared to have a delay in the release of torsion.

Hollingsworth, K G; Hodgson, T; MacGowan, G A; Blamire, A M; Newton, J L



Assessment of cardiac iron deposition in sickle cell disease using 3.0 Tesla cardiovascular magnetic resonance.  


Many patients with sickle cell disease receive blood transfusions as a life-saving treatment. However, excess transfusions may lead to increased body iron burden. Specifically, heart failure due to cardiac iron overload is the leading cause of death in these patients. The purpose of this study was to investigate the potential role of high-field 3.0-Tesla (T) cardiovascular magnetic resonance (CMR) for assessment of cardiac iron content by measuring the transverse relaxivity rate R2*. The R2* was measured in calibrated phantoms with different iron concentrations at 3.0T and 1.5T using optimized pulse sequences. Myocardial R2* was measured at 3.0T in a group of sickle cell disease patients with different disease stages, and the results were compared to the serum ferritin levels and hepatic R2*. The phantom R2* measurements at 3.0T were double those at 1.5T, and the measurements of both systems showed linear relationships with iron concentration. The 3.0T R2* was more sensitive than 1.5T in detecting low iron concentration. In patients, myocardial R2* had weak and good correlations with hepatic R2* and serum ferritin levels, respectively. Bland-Altman analysis showed low inter- and intra-observer variabilities. In conclusion, measuring myocardial R2* at 3.0T is a promising technique with high sensitivity and reproducibility for evaluating cardiac iron overload in sickle cell disease patients. PMID:22563880

Ibrahim, El-Sayed H; Rana, Fauzia N; Johnson, Kevin R; White, Richard D



Cardiac disease in mucopolysaccharidosis type I attributed to catecholaminergic and hemodynamic deficiencies  

PubMed Central

Cardiac dysfunction is a common cause of death among pediatric patients with mutations in the lysosomal hydrolase ?-l-iduronidase (IDUA) gene, which causes mucopolysaccharidosis type I (MPS-I). The purpose of this study was to analyze adrenergic regulation of cardiac hemodynamic function in MPS-I. An analysis of murine heart function was performed using conductance micromanometry to assess in vivo cardiac hemodynamics. Although MPS-I (IDUA?/?) mice were able to maintain normal cardiac output and ejection fraction at baseline, this cohort had significantly compromised systolic and diastolic function compared with IDUA+/? control mice. During dobutamine infusion MPS-I mice did not significantly increase cardiac output from baseline, indicative of blunted cardiac reserve. Autonomic tone, measured functionally by ?-blockade, indicated that MPS-I mice required catecholaminergic stimulation to maintain baseline hemodynamics. Survival analysis showed mortality only among MPS-I mice. Linear regression analysis revealed that heightened end-systolic volume in the resting heart is significantly correlated with susceptibility to mortality in MPS-I hearts. This study reveals that cardiac remodeling in the pathology of MPS-I involves heightened adrenergic tone at the expense of cardiac reserve with cardiac decompensation predicted on the basis of increased baseline systolic volumes.

Palpant, Nathan J.; Bedada, Fikru B.; Peacock, Brandon; Blazar, Bruce R.; Metzger, Joseph M.



Effect of right ventricular pacing on cardiac apex rotation assessed by a gyroscopic sensor.  


To quantify cardiac apex rotation (CAR), the authors recently proposed the use of a Coriolis force sensor (gyroscope) as an alternative to other complex techniques. The aim of this study was to evaluate the effects of right ventricular (RV) pacing on CAR. A sheep heart was initially paced from the right atrium to induce a normal activation sequence at a fixed heart rate (AAI mode) and then an atrioventricular pacing was performed (DOO mode, AV delay = 60 ms). A small gyroscope was epicardially glued on the cardiac apex to measure the angular velocity (Ang V). From AAI to DOO pacing mode, an increase (+9.2%, p < 0.05) of the maximum systolic twisting velocity (Ang VMAX) and a marked decrease (-19.9%, p < 0.05) of the maximum diastolic untwisting velocity (Ang VMIN) resulted. RV pacing had negligible effects (-3.1%, p = 0.09) on the maximum angle of CAR, obtained by integrating Ang V. The hemodynamic parameters of systolic (LVdP/dtMAX) and diastolic (LVdP/dtMIN) cardiac function showed slight variations (-3.8%, p < 0.05 and +3.9%, p < 0.05, respectively). Results suggest that cardiac dyssynchrony induced by RV pacing can alter the normal physiological ventricular twist patterns, particularly affecting diastolic untwisting velocity. PMID:17515719

Marcelli, Emanuela; Cercenelli, Laura; Parlapiano, Mario; Fumero, Roberto; Bagnoli, Paola; Costantino, Maria Laura; Plicchi, Gianni


MIBG scintigraphic assessment of cardiac adrenergic activity in response to altitude hypoxia  

SciTech Connect

High altitude hypoxia induces a decrease in the cardiac chronotropic function at maximal exercise or in response to isoproterenol infusion, suggesting an alteration in the cardiac sympathetic activation. Iodine-123 metaiodobenzylguanidine (({sup 123}I)MIBG) was used to map scintigraphically the cardiac sympathetic neuronal function in six male subjects (aged 32 {plus minus} 7 yr) after an exposure to high altitude that created hypoxic conditions. Results obtained just after return to sea level (RSL) were compared with the normal values obtained after 2 or 3 mo of normoxia (N). A static image was created as the sum of the 16-EKG gated images recorded for 10 min in the anterior view of the chest at 20, 60, 120, and 240 min after injection. Regions of interest were located over the heart (H), lungs (L), and mediastinum (M) regions. There was a significant decrease in the H/M and the L/M ratios in RSL compared to N condition. Plasma norepinephrine concentration was elevated during the stay at altitude but not significantly different in RSL compared to N. In conclusion, cardiac ({sup 123}I)MIBG uptake is reduced after an exposure to altitude hypoxia, supporting the hypothesis of an hypoxia-induced reduction of adrenergic neurotransmitter reserve in the myocardium. Furthermore, the observed significant decrease in pulmonary MIBG uptake suggests an alteration of endothelial cell function after exposure to chronic hypoxia.

Richalet, J.P.; Merlet, P.; Bourguignon, M.; Le-Trong, J.L.; Keromes, A.; Rathat, C.; Jouve, B.; Hot, M.A.; Castaigne, A.; Syrota, A. (Unite INSERM U 138, Faculte de Medecine, Creteil (France))



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

Microsoft Academic Search

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

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



Echocardiographic assessment of cardiac function and morphology in patients with generalised lipodystrophy  

Microsoft Academic Search

Because cardiomegaly has been observed in lipodystrophic patients we studied cardiac morphology and function with one- and two-dimensional echocardiography in addition to general cardiologic examination in a series of seven patients. Muscular hypertrophy with increased chamber size and myocardial indentations were found. Two patients had asymmetrical septal hypertrophy (ASH), and two patients demonstrated systolic anterior movement (SAM) of the mitral

P. G. Bjørnstad; B. K. H. Semb; O. Trygstad; M. Seip



Beyond auscultation - acoustic cardiography in the diagnosis and assessment of cardiac disease  

Microsoft Academic Search

Auscultation has long been an important part of the evaluation of patients with known and sus- pected cardiac disease. The subsequent develop- ment of phonocardiography provided an ana- logue visual display that permitted a more de- tailed analysis of the timing and acoustical charac- teristics of heart sounds, murmurs, clicks and rubs. In addition, the measurement of systolic time intervals

Paul Erne



Health Technology Assessment Reports, 1989. Number 6. Cardiac Catheterization in a Freestanding Setting.  

National Technical Information Service (NTIS)

Cardiac catheterization is a procedure used to diagnose and treat heart disease. The procedure involves inserting the tip of a small catheter into a patient's blood vessel and advancing it until the tip of the catheter is placed in or near the heart. When...

M. N. Jackson



Assessment of cardiac safety for PPAR? agonists in rodent models of heart failure: a translational medicine perspective.  


PPAR?-modulators, a class of anti-diabetic drugs as represented by thiazolidinediones (TZD), have been associated with cardiovascular risks in type-2 diabetes in humans but a similar liability has not been demonstrated in preclinical models. This gap between clinical and preclinical observations may reflect the lack of a translational model for cardiac safety assessment because preclinical efficacy for glycemic control for PPAR?-modulators is routinely conducted in animals with diabetic background while drug safety study is performed in young and health animals with little risk of heart failure, in contrast to the complex pathophysiological conditions of patients subjected to the treatment of TZDs. Therefore, some key steps are important to address this translational gap. First, it is essential to use an appropriate translational model that mimics most of human pathophysiology for the assessment of cardiovascular safety for TZDs. Second, it calls for the discovery of a translational biomarker (most likely a collection of biomarkers due to multiple risk factors contributed to the complex disease) to be able to sensitively detect the disease progression and in response to therapy. Specific examples are provided in this review for the use of a rodent model of myocardial infarction-induced heart failure to address the cardiac safety concern in response to chronic treatment of rosiglitazone. Multiple biomarkers, including physiological, biochemical, pharmacogenomic and imaging biomarkers, were applied to assess the cardiovascular risk in this heart failure model. The data and strategic approach are discussed from translational medicine perspectives. PMID:22122456

Wang, Xinkang



Validation of transcatheter left ventricular electromechanical mapping for assessment of cardiac function and targeted transendocardial injection in a porcine ischemia-reperfusion model  

PubMed Central

Ischemic heart disease, despite advances in treatment, remains the major cause of mortality worldwide. NOGA 3D left ventricular electromechanical mapping allows accurate determination of cardiac function and precise identification of sites of injury. In a porcine model of ischemia-reperfusion injury, we validate the use of the NOGA mapping system for assessment of cardiac function along with the Myostar injection catheter for directed delivery of therapeutics to localized target sites in the setting of acute myocardial injury.

Taghavi, Sharven; Duran, Jason M; Berretta, Remus M; Makarewich, Catherine A; Udeshi, Foram; Sharp, Thomas E; Kubo, Hajime; Houser, Steven R; George, Jon C



Validation of transcatheter left ventricular electromechanical mapping for assessment of cardiac function and targeted transendocardial injection in a porcine ischemia-reperfusion model.  


Ischemic heart disease, despite advances in treatment, remains the major cause of mortality worldwide. NOGA 3D left ventricular electromechanical mapping allows accurate determination of cardiac function and precise identification of sites of injury. In a porcine model of ischemia-reperfusion injury, we validate the use of the NOGA mapping system for assessment of cardiac function along with the Myostar injection catheter for directed delivery of therapeutics to localized target sites in the setting of acute myocardial injury. PMID:22611476

Taghavi, Sharven; Duran, Jason M; Berretta, Remus M; Makarewich, Catherine A; Udeshi, Foram; Sharp, Thomas E; Kubo, Hajime; Houser, Steven R; George, Jon C



Are Output Fluctuations Transitory?  

Microsoft Academic Search

According to the conventional view of the business cycle, fluctuations in output represent temporary deviations from trend. The purpose of this paper is to question this conventional view. If fluctuations in output are dominated by temporary deviations from the natural rate of output, then an unexpected change in output today should not substantially change one's forecast of output in, say,

John Y. Campbell; N. Gregory Mankiw



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

PubMed Central

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

Palmer, Thomas G.; Uhl, Timothy L.



Cardiac assessment prior to vascular surgery: Is dipyridamole-sestamibi necessary?  

Microsoft Academic Search

Dipyridamole-sestamibi (PMIBI) is recommended prior to vascular surgery in patients with 1 Eagle criteria (Q waves, history of ventricular ectopy, diabetes, advanced age, and\\/or angina). To review our cardiac morbidity and mortality and the need for preoperative PMIBI, we reviewed 109 consecutive patients with a mean age of 59 years who underwent 145 elective major vascular procedures over a 1-year

Christian de Virgilio; Sang Pak; Tracey Arnell; Carlos Donayre; Roger J. Lewis; Bruce E. Stabile; Rodney White



Fundamentals of ECG Interpretation in Clinical Research and Cardiac Safety Assessment  

Microsoft Academic Search

The interpretation of ECGs recorded during clinical drug trials shares many similarities with the clinical interpretation\\u000a of ECGs, but also differs in several significant ways. The fundamental rules for measurement of ECG intervals and overall\\u000a ECG interpretation (cardiac rhythm, conduction, etc.) are identical whether an ECG is recorded from a patient having chest\\u000a pain in an emergency room, or from

Ihor Gussak; Robert Kleiman; Jeffrey S. Litwin


Self-report measures for assessing treatment outcomes in cardiac surgery patients.  


Patient self-report measures are increasingly valued as outcome variables in health services research studies. In this article, the authors describe the Functional Status, Health Related Quality of Life, Life Satisfaction, and Patient Satisfaction scales included in the Processes, Structures, and Outcomes of Cardiac Surgery (PSOCS) cooperative study underway within the Department of Veterans Affairs health care system. In addition to reporting on the baseline psychometric characteristics of these instruments, the authors compared preoperative Medical Outcomes Study SF-36 data from the study patients with survey data from a probability sample of the US population and with preoperative data on cardiac surgery patients from a high volume private sector surgical practice. Descriptive analyses indicate that the SF-36 profiles for all of the cardiac patients are highly similar. The Veterans Affairs and private sector patients report diminished physical functioning, physical role functioning, and emotional role functioning as well as reduced energy relative to an age-matched comparison sample. At the same time, however, the Veterans Affairs patients evidenced lower levels of capacity on most of the SF-36 dimensions relative to the private sector patients. PMID:7475415

McCarthy, M J; Shroyer, A L; Sethi, G K; Moritz, T E; Henderson, W G; Grover, F L; London, M J; Gibbs, J O; Lansky, D; Miller, D



Relationship between peak cardiac pumping capability and indices of cardio-respiratory fitness in healthy individuals.  


Cardiac power output (CPO) is a unique and direct measure of overall cardiac function (i.e. cardiac pumping capability) that integrates both flow- and pressure-generating capacities of the heart. The present study assessed the relationship between peak exercise CPO and selected indices of cardio-respiratory fitness. Thirty-seven healthy adults (23 men and 14 women) performed an incremental exercise test to volitional fatigue using the Bruce protocol with gas exchange and ventilatory measurements. Following a 40-min recovery, the subjects performed a constant maximum workload exercise test at or above 95% of maximal oxygen consumption. Cardiac output was measured using the exponential CO(2) rebreathing method. The CPO, expressed in W, was calculated as the product of the mean arterial blood pressure and cardiac output. At peak exercise, CPO was well correlated with cardiac output (r = 0·92, P<0·01), stroke volume (r = 0·90, P<0·01) and peak oxygen consumption (r = 0·77, P<0·01). The coefficient of correlation was moderate between CPO and anaerobic threshold (r = 0·47, P<0·01), oxygen pulse (r = 0·57, P<0·01), minute ventilation (r = 0·53, P<0·01) and carbon dioxide production (r = 0·56, P<0·01). Small but significant relationship was found between peak CPO and peak heart rate (r = 0·23, P<0·05). These findings suggest that only peak cardiac output and stroke volume truly reflect CPO. Other indices of cardio-respiratory fitness such as oxygen consumption, anaerobic threshold, oxygen pulse, minute ventilation, carbon dioxide production and heart rate should not be used as surrogates for overall cardiac function and pumping capability of the heart. PMID:22856346

Jakovljevic, Djordje G; Popadic-Gacesa, Jelena Z; Barak, Otto F; Nunan, David; Donovan, Gay; Trenell, Michael I; Grujic, Nikola G; Brodie, David A



Prediction of Cardiac Events in Patients with Reduced Left Ventricular Ejection Fraction Using Dobutamine Cardiovascular Magnetic Resonance Assessment of Wall Motion Score Index  

PubMed Central

Objectives To assess the utility of dobutamine cardiovascular magnetic resonance (DCMR) results for predicting cardiac events in individuals with reduced left ventricular ejection fraction (LVEF). Background It is unknown whether DCMR results identify a poor cardiac prognosis when the resting LVEF is moderately to severely reduced. Methods Two-hundred consecutive patients aged 30 to 88 (average 64) years with a LVEF ?55% that were poorly suited for stress echocardiography, underwent DCMR in which LV wall motion score index (WMSI), defined as the average wall motion of the number of segments scored, was assessed at rest, during low dose, and after peak intravenous infusion of dobutamine/atropine. All participants were followed for an average of 5 years after DCMR to ascertain the post testing occurrence of cardiac death, myocardial infarction (MI), and unstable angina or congestive heart failure warranting hospitalization. Results After accounting for risk factors associated with coronary arteriosclerosis and MI, a stress induced increase in WMSI during DCMR was associated with future cardiac events (p< 0.001). After accounting for resting LVEF, a DCMR stress induced change in WMSI added significantly to predicting future cardiac events (p=0.003), but this predictive value was confined primarily to those with a LVEF >40%. Conclusions In individuals with mild to moderate reductions in LVEF (40% to 55%), dobutamine induced increases in WMSI forecast MI and cardiac death to a greater extent than an assessment of resting LVEF. In those with a LVEF < 40%, a dobutamine induced increase in WMSI does not predict MI and cardiac death beyond the assessment of resting LVEF.

Dall'Armellina, Erica; Morgan, Timothy M.; Mandapaka, Sangeeta; Ntim, William; Carr, J. Jeffrey; Hamilton, Craig A.; Hoyle, John; Clark, Hollins; Clark, Paige; Link, Kerry M.; Case, Doug; Hundley, W. Gregory



Multicentre evaluation of the diagnostic value of cardiac troponin T, CK-MB mass, and myoglobin for assessing patients with suspected acute coronary syndromes in routine clinical practice  

PubMed Central

Objective: To assess the diagnostic efficiency of the third generation cardiac troponin T assay in routine clinical practice. Design: Prospective observational study of unselected consecutive admissions. Setting: Multicentre study in 43 teaching and non-teaching hospitals in 13 countries. Subjects: 1105 hospital admissions, median age 67 years (range 15–96 years, 63.7% male) with suspected acute coronary syndromes (72.3% of cases) or other non-specific symptoms where cardiac disease required exclusion (27.7%). Interventions: Over the study period, myoglobin, creatine kinase MB isoenzyme (CK-MB), and cardiac troponin T where measured in parallel with conventional diagnostic tests. Final diagnostic classification involved standard ECG changes and CK-MB mass exceeding 5.0 ?g/l. Main outcome measures: Diagnostic efficiency was assessed by receiver operator characteristic curve analysis including and excluding patients with unstable angina. Results: Measurement of cardiac troponin T was diagnostically equivalent to CK-MB and both were better than myoglobin, with areas under the curve at 12 hours of 0.94, 0.99, and 0.80, respectively. Diagnostic criteria using CK-MB were inadequate and showed bias when patients with unstable angina were included. Elevations of cardiac troponin T did not occur when cardiac disease could be categorically excluded but were found in clinical conditions other than suspected acute coronary syndromes. Conclusions: CK-MB is unsuitable as a diagnostic gold standard even at the proposed lower threshold. A lower cut off for cardiac troponin T of 0.05 ?g/l should be used for diagnosis of acute myocardial infarction. Diagnosis of acute myocardial infarction cannot be made solely on the basis of a cardiac troponin T result.

Collinson, P O; Stubbs, P J; Kessler, A-C



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

NASA Astrophysics Data System (ADS)

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

Shuman, J.; Shugart, H.



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


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

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



Combining clinical and thallium data optimizes preoperative assessment of cardiac risk before major vascular surgery  

SciTech Connect

STUDY OBJECTIVE: To determine whether clinical markers and preoperative dipyridamole-thallium imaging are both useful in predicting ischemic events after vascular surgery. Two hundred fifty-four consecutive patients were referred to a nuclear cardiology laboratory before surgery. Forty-four patients had surgery cancelled or postponed after clinical evaluation and dipyridamole-thallium imaging. Surgery was not confirmed for ten. Two hundred patients receiving prompt vascular surgery were the study group. Thirty patients (15%) had early postoperative cardiac ischemic events, with cardiac death in 6 (3%) and nonfatal myocardial infarction in 9 (4.5%). Logistic regression identified five clinical predictors (Q waves, history of ventricular ectopic activity, diabetes, advanced age, angina) and two dipyridamole-thallium predictors of postoperative events. Of patients with none of the clinical variables (n = 64), only 2 (3.1%; 95% CI, 0% to 8%) had ischemic events with no cardiac deaths. Ten of twenty (50%; 95% CI, 29% to 71%) patients with three or more clinical markers had events. Eighteen of one hundred sixteen (15.5%; 95% CI, 7% to 21%) patients with either 1 or 2 clinical predictors had events. Within this group, 2 of 62 (3.2%; 95% CI, 0% to 8%) patients without thallium redistribution had events compared with 16 events in 54 patients (29.6%; 95% CI, 16% to 44%) with thallium redistribution. The multivariate model using both clinical and thallium variables showed significantly higher specificity at equivalent sensitivity levels than models using either clinical or thallium variables alone. Preoperative dipyridamole-thallium imaging appears most useful to stratify vascular patients determined to be at intermediate risk by clinical evaluation.

Eagle, K.A.; Coley, C.M.; Newell, J.B.; Brewster, D.C.; Darling, R.C.; Strauss, H.W.; Guiney, T.E.; Boucher, C.A.



Non-invasive cardiac imaging techniques and vascular tools for the assessment of cardiovascular disease in type 2 diabetes mellitus  

PubMed Central

Cardiovascular disease is the major cause of mortality in type 2 diabetes mellitus. The criteria for the selection of those asymptomatic patients with type 2 diabetes who should undergo cardiac screening and the therapeutic consequences of screening remain controversial. Non-invasive techniques as markers of atherosclerosis and myocardial ischaemia may aid risk stratification and the implementation of tailored therapy for the patient with type 2 diabetes. In the present article we review the literature on the implementation of non-invasive vascular tools and cardiac imaging techniques in this patient group. The value of these techniques as endpoints in clinical trials and as risk estimators in asymptomatic diabetic patients is discussed. Carotid intima–media thickness, arterial stiffness and flow-mediated dilation are abnormal long before the onset of type 2 diabetes. These vascular tools are therefore most likely to be useful for the identification of ‘at risk’ patients during the early stages of atherosclerotic disease. The additional value of these tools in risk stratification and tailored therapy in type 2 diabetes remains to be proven. Cardiac imaging techniques are more justified in individuals with a strong clinical suspicion of advanced coronary heart disease (CHD). Asymptomatic myocardial ischaemia can be detected by stress echocardiography and myocardial perfusion imaging. The more recently developed non-invasive multi-slice computed tomography angiography is recommended for exclusion of CHD, and can therefore be used to screen asymptomatic patients with type 2 diabetes, but has the associated disadvantages of high radiation exposure and costs. Therefore, we propose an algorithm for the screening of asymptomatic diabetic patients, the first step of which consists of coronary artery calcium score assessment and exercise ECG.

Beishuizen, E. D.; Pereira, A. M.; Rabelink, T. J.; Smit, J. W.; Tamsma, J. T.; Huisman, M. V.; Jukema, J. W.



Real time assessment of RF cardiac tissue ablation with optical spectroscopy  

SciTech Connect

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

Demos, S G; Sharareh, S



Noninvasive assessment of cardiopulmonary function in critically ill infants and children.  


Echocardiography and Doppler echocardiography allow for the accurate noninvasive assessment of cardiac structure and function. Two-dimensional echocardiography accurately demonstrates both normal and abnormal intracardiac and great vessel anatomy and assists in differentiating cardiac from noncardiac causes of respiratory distress. M-mode echocardiography allows for documentation of cardiac chamber size and left ventricular function. Doppler echocardiography is used to measure cardiac output, assess AV and semilunar valve function, detect abnormal flow patterns within the heart and great vessels, and assist in the assessment of pulmonary artery pressures. This article discusses the uses of all these modalities as they apply to the critically ill infant and child. PMID:3322647

Fripp, R R; Berman, W



Radiation dose exposure of patients undergoing 320-row cardiac CT for assessing coronary angiography and global left ventricular function.  


A 320-row multidetector CT provides the capability for prospective electrocardiogram (ECG)-gated coronary CT angiography (CTA) and tube current modulated cardiac function assessment (CFA). We assessed and compared the effective radiation dose of these two modes. On a prospective basis, we performed ECG-gated cardiac CT on 119 patients (87 were males). For heart rates (HRs) /=80 bpm were scanned with either two or three heartbeats acquisitions, respectively. We used two types of scans. One type was based on a prospective ECG-gated CTA mode and the other using a tube current modulated CFA mode covering an entire R-R interval. The mean BMI of patients was 25.4 (range 18.8-49.3). Fifty-one patients (42.9 %) underwent CFA scanning, while the remaining 68 (57.1 %) had CTA. The majority of patients completed the scan in a single heartbeat (59.7 %). The mean dose of CTA mode at 65-85 % phase window for one and two heartbeats was 3.68 mSv (2.40-7.23) and 8.61 mSv (6.76-10.60), respectively. The mean dose of CFA mode for a single heartbeat measurement with dose modulation (25 % dose for CFA, and 100 % dose during 65-85 % phase window for CTA) was 6.32 mSv (4.69-8.89). CTA with prospective ECG-gating allows for acceptable image quality and radiation dose. HR reduction is mandatory to minimize radiation exposure. Global left ventricle function can be assessed with a single heartbeat within an acceptable radiation dose. PMID:22610716

Chen, Chien-Ming; Liu, Yuan-Chang; Chen, Chun-Chi; Wen, Ming-Shien; Hung, Chien-Fu; Wan, Yung-Liang



The hemodynamics of cardiac tamponade.  


The changes produced by acute pericardial tamponade were examined. Tamponade produced the expected hemodynamic alteration; namely, depression on cardiac output, left ventricular pressure and LV dp/dt and elevation of right atrial and intrapericardial pressures. The mechanism of the hemodynamic disturbances was that the elevation of the intrapericardial pressure produced a negative atrial transmural pressure and disturbed atrial and ventricle filling producing the vicious cycle: diminished venoatrial gradient leads to decreased cardiac output leads to attenuated effect of ventricular systole on atrial filling, and so forth. The myocardial contractility was not impaired in cardiac tamponade. PMID:642185

Nakata, Y; Takahashi, F



Safety assessment and biodistribution of povidone as a coating material for cardiac pacing leads  

SciTech Connect

Cardiac pacing leads coated with povidone-(/sup 131/I) were implanted in dogs and the leaching of radioactivity from the leads was monitored by external scintigraphy. The activity which had dissipated from the pacing leads was not as (/sup 131/I)-iodide, but as povidone-(/sup 131/I). Only 50% (mean) of the activity remained on the pacing leads after two weeks while a significant amount of radioactivity was eliminated via urine and feces. The liver was a major site of accumulation of retained activity which had leached off the pacing leads. There was no evidence of large pieces of povidone-(/sup 131/I) in the lungs of the dogs, all of which appeared healthy at the time of sacrifice. The results of this study support the conclusions of a long-term study indicating that povidone is a safe and suitable coating material for pacing leads.

Jay, M.; Digenis, G.A.



Un nuovo test (VITTORIO Test) per la valutazione dell'efficienza fisica in soggetti ammessi a programmi di riabilitazione dopo intervento di chirurgia cardiaca A new test (VITTORIO Test) for functional fitness assessment in rehabilitation after cardiac surgery  

Microsoft Academic Search

A new test (VITTORIO Test) for functional fitness assessment in rehabilitation after cardiac surgery. G. Calsamiglia, F. Camera, A. Mazza, P. Villa, F. Gigli Berzolari, R. Tramarin, F. Cobelli. An adequate assessment of physical function (PF) in Cardiac Rehabilitation (CR) plays a central role in early de- tection of physical limitations. Traditionally exercise toler- ance has been used as an

Giuseppe Calsamiglia; Federica Camera; Antonio Mazza; Paola Villa; Francesca Gigli Berzolari; Roberto Tramarin; Franco Cobelli


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

PubMed Central

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

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



Assessment of NGAL as an early biomarker of acute kidney injury in adult cardiac surgery patients.  


Early and predictive acute kidney injury (AKI) markers may be decisive for the clinical outcome of heart surgery. Hence, this study set out to evaluate the biological variability of urinary neutrophil gelatinase-associated lipocalin (uNGAL) levels in adult cardiac surgery patients, to test their feasibility as a biomarker of early AKI in a routine laboratory setting. uNGAL levels were measured with an automated immunoassay in urine samples from patients undergoing cardiac surgery using cardiopulmonary bypass, at the time of admission (T0) and 4 hours (T1) and 24 hours (T2) after surgery. Patients without post-operative AKI did not show significant differences in urine NGAL levels after surgery. In contrast, patients developing AKI displayed a significant increase (P=0.011) in uNGAL levels compared to T0. This increase was detectable at an earlier time point (T1, 4 hours) with respect to serum creatinine (T2, 24 hours). Confirming its utility as a biomarker, at T1 the uNGAL levels were significantly higher in AKI patients than in non-AKI patients (P=0.021). A receiver operating characteristic curve analysis of the uNGAL assay gave a sensitivity of 55.3 (95percent confidence interval, 26.59-78.73), a specificity of 72.9 (95 percent CI, 55.88-86.21), and a cut-off value for AKI prediction of 55.2. These results support the notion that urinary NGAL is an earlier marker of AKI than serum creatinine. However, the cut-off value of the assay was too low to consider it as a positive or negative diagnostic marker in AKI patients with moderate degree of severity. Likewise, its sensitivity and specificity were not high enough for it to be considered better than the others currently in use. PMID:23034268

Sargentini, V; Mariani, P; D' Alessandro, M; Pistolesi, V; Lauretta, M P; Pacini, F; Tritapepe, L; Morabito, S; Bachetoni, A


Plasma Brain Natriuretic Peptide Levels in Cardiac Function Assessment in Chronic Dialysis Patients.  


BACKGROUND: Brain natriuretic peptide (BNP) is elevated in patients with end-stage renal disease and could reflect left ventricular dysfunction. Aim: To evaluate the plasma levels of BNP in two groups of asymptomatic patients on different dialysis programs and to correlate their variations with echocardiographic parameters. METHODS: Group A consisted of 36 patients on chronic hemodialysis (HD), and group B included 38 patients on continuous ambulatory peritoneal dialysis (CAPD). ECG and echocardiography were performed, and concomitantly plasma BNP levels were determined before and after a regular 4-hour session in HD patients and before performing a dialysate exchange in patients on CAPD. RESULTS: BNP values in group A were found to be higher than in group B (419 ± 76 vs. 193 ± 56 pg/ml; p < 0.03). The cutoff point which discriminated both groups was 194 pg/ml (sensitivity: 64% and specificity: 76%; p = 0.001). Significant differences were found with respect to the following echocardiographic data (group A vs. group B): left atrial (LA) size (40 ± 13 vs. 34 ± 1 mm), LA volume (59 ± 16 vs. 41 ± 32 ml), transmitral flow E/A (1.17 ± 0.01 vs. 0.9 ± 0.06), the movement of the mitral valve annulus e/a (tissue Doppler imaging; 1.19 ± 0.15 vs. 1.05 ± 0.13) and left ventricular mass index (133 ± 10 vs. 108 ± 11). CONCLUSION: Patients on CAPD had lower levels of BNP, and echocardiographic findings indicated decreased volume overload. In asymptomatic patients, marked increases in BNP levels may reflect early stages of pathological processes that precede the development of apparent cardiac manifestations (left ventricular hypertrophy). Only echocardiographic parameters of cardiac dysfunction should be used as diagnostic criteria. PMID:22258537

Sanjuan, R; Oliva, S Martín; Blasco, M L; Puchades, M; Torregrosa, I; Ramón, R García; Carrasco, A Miguel



Prevalence of troponin elevations in patients with cardiac arrest and implications for assessing quality of care in hypothermia centers.  


The prevalence of troponin elevations in patients with cardiac arrest (CA) using newer generation troponin assays when the ninety-ninth percentile is used has not been well described. We studied patients admitted with CA without ST elevation myocardial infarction (MI). Treatment included a multidisciplinary protocol that included routine use of hypothermia for appropriate patients. Serial assessment of cardiac biomarkers, including troponin I was obtained over the initial 24 to 36 hours. Patients were classified into 1 of 5 groups on the basis of multiples of the ninety-ninth percentile (upper reference limit [URL]), using the peak troponin I value: <1×, 1 to 3×, 3 to 5×, 5 to 10×, and >10×. Serial changes between the initial and second troponin I values were also assessed. A total of 165 patients with CA (mean age 58 ± 16, 67% men) were included. Troponin I was detectable in all but 2 patients (99%); all others had peak troponin I values that were greater than or equal to the URL. Most patients had peak troponin I values >10× URL, including patients with ventricular fibrillation or ventricular tachycardia (85%), asystole (50%), and pulseless electrical activity (59%). Serial changes in troponin I were present in almost all patients: ?20% change in 162 (98%), ?30% change in 159 (96%), and an absolute increase of ?0.02 ng/ml in 85% of patients. In conclusion, almost all patients with CA who survived to admission had detectable troponin I, most of whom met biomarker guideline criteria for MI. Given the high mortality of these patients, these data have important implications for MI mortality reporting at CA treatment centers. PMID:23800547

Kontos, Michael C; Ornato, Joseph P; Kurz, Michael C; Roberts, Charlotte S; Gossip, Michelle; Dhindsa, Harinder S; Reid, Renee D; Peberdy, Mary A



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

SciTech Connect

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

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



Automated Assessment of Mitral Regurgitant Volume and Regurgitant Fraction by a Newly Developed Digital Color Doppler Velocity Profile Integration Method  

Microsoft Academic Search

Recent development of the automated cardiac flow measurement (ACFM) method has provided automated measurement of stroke volume and cardiac output by spatial and temporal integration of digital Doppler velocity profile data. The purpose of this study was to evaluate the clinical usefulness of the ACFM method using digital color Doppler velocity profile integration in the assessment of mitral regurgitant volume

Takeshi Hozumi; Kiyoshi Yoshida; Takashi Akasaka; Tsutomu Takagi; Atsushi Yamamuro; Toshikazu Yagi; Junichi Yoshikawa



Echocardiographic Assessment of Cardiac Involvement in Patients with Thalassemia Major: Evidence of Abnormal Relaxation Pattern of the Left Ventricle in Children and Young Patients  

Microsoft Academic Search

Background- Cardiac involvement which leads to congestive heart failure (CHF) is a major cause of death in patients with thalassemia major due to hemosiderosis and chronic anemia. Although the left ventricular (LV) systolic function in patients with thalassemia major has been considerably studied, LV diastolic function has not been assessed adequately. In this current study we used Doppler echocardiography to

A. Shahmohammadi; P. N. Davari; Y. Aarabi; M. Meraji; A. Tabib; H. Mortezaeian


Cardiac magnetic resonance, transthoracic and transoesophageal echocardiography: a comparison of in vivo assessment of ventricular function in rats.  


In vivo assessment of ventricular function in rodents has largely been restricted to transthoracic echocardiography (TTE). However 1.5?T cardiac magnetic resonance (CMR) and transoesophageal echocardiography (TOE) have emerged as possible alternatives. Yet, to date, no study has systematically assessed these three imaging modalities in determining ejection fraction (EF) in rats. Twenty rats underwent imaging four weeks after surgically-induced myocardial infarction. CMR was performed on a 1.5?T scanner, TTE was conducted using a 9.2?MHz transducer and TOE was performed with a 10?MHz intracardiac echo catheter. Correlation between the three techniques for EF determination and analysis reproducibility was assessed. Moderate-strong correlation was observed between the three modalities; the greatest between CMR and TOE (intraclass correlation coefficient (ICC)?=?0.89), followed by TOE and TTE (ICC?=?0.70) and CMR and TTE (ICC?=?0.63). Intra- and inter-observer variations were excellent with CMR (ICC?=?0.99 and 0.98 respectively), very good with TTE (0.90 and 0.89) and TOE (0.87 and 0.84). Each modality is a viable option for evaluating ventricular function in rats, however the high image quality and excellent reproducibility of CMR offers distinct advantages even at 1.5?T with conventional coils and software. PMID:23836849

Richardson, Jd; Bertaso, Ag; Frost, L; Psaltis, Pj; Carbone, A; Koschade, B; Wong, Dt; Nelson, Aj; Paton, S; Williams, K; Azarisman, S; Worthley, Mi; Teo, Ks; Gronthos, S; Zannettino, Acw; Worthley, Sg



Caffeine enhances doxorubicin cardiac toxicity in an animal model  

Microsoft Academic Search

Based on in vitro data suggesting an interaction between methylxanthines and doxorubicin in regulating Ca2+ across muscle sarcoplasmic reticulum, this study was designed to test the hypothesis that a commonly used methylxanthine, caffeine, might influence the cardiac toxicity of doxorubicin. Three days following doxorubicin treatment, in vivo intracardiac pressures, cardiac outputs, in vitro cardiac weights, and cardiac electron microscopy were

Jeffrey D. Hosenpud; Jay Wright; Leonard Simpson; Jonathan J. Abramson



Generalized Radar Output Simulation.  

National Technical Information Service (NTIS)

Using the outputs from the simulation of overall body motion related to observations at a complex of earth stations, this report develops a model for generating the scattering matrix and radar output voltages. The general multistatic case is treated using...

J. F. A. Ormsby S. H. Bickel



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

ERIC Educational Resources Information Center

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

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



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

ERIC Educational Resources Information Center

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

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



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

SciTech Connect

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

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



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

Microsoft Academic Search

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

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



Calibration of Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures  

NASA Astrophysics Data System (ADS)

Kodak EDR2 film has been calibrated across the range of exposure conditions encountered in our cardiac catheterization laboratory. Its dose-response function has been successfully modelled, up to the saturation point of 1 Gy. The most important factor affecting film sensitivity is the use of beam filtration. Spectral filtration and kVp together account for a variation in dose per optical density of -10% to +25%, at 160 mGy. The use of a dynamic wedge filter may cause doses to be underestimated by up to 6%. The film is relatively insensitive to variations in batch, field size, exposure rate, time to processing and day-to-day fluctuations in processor performance. Overall uncertainty in the calibration is estimated to be -20% to +40%, at 160 mGy. However, the uncertainty increases at higher doses, as the curve saturates. Artefacts were seen on a number of films, due to faults in the light-proofing of the film packets.

Morrell, Rachel E.; Rogers, Andy



Coronary artery calcium score assessed by a 64 multislice computed tomography and early indexes of functional and structural vascular remodeling in cardiac syndrome X patients  

Microsoft Academic Search

Background. Regardless of normal coronary angiograms, coronary artery calcium (CAC) can be found in cardiac syndrome X (CSX) patients.\\u000a According to some data, a relationship between the CAC score and markers of early atherosclerosis in CSX has been observed.\\u000a Our aim was to assess whether the extent of the CAC score assessed by multislice computed tomography (MSCT) with a 64-slice

Katarzyna Mizia-Stec; Maciej Haberka; Magdalena Mizia; Artur Chmiel; Joanna Wierzbicka-Chmiel; Mariusz Skowerski; Zbigniew Gasior



Cardiac disease in pregnancy: value of echocardiography.  


Cardiovascular disease in women during pregnancy poses particular challenges. It continues to be a leading cause of maternal mortality and contributes to significant morbidity. Echocardiography is essential in characterizing the extent and effects of heart disease prior to, during, and after pregnancy. By understanding the physiologic adaptation in pregnancy with increases in heart rate, blood volume, and cardiac output, and decrease in vascular resistance, one can anticipate and recognize the effects of these changes on various cardiac lesions. Cardiomyopathy, severe, obstructive valvular disease, aortic dilation due to Marfan's disease, and cyanotic congenital heart disease are poorly tolerated in pregnancy. These disorders can be readily distinguished from normal structural changes of pregnancy and their severity assessed by echocardiography. Cardiovascular disease in women of reproductive age requires careful, multidisciplinary management by obstetric and medical teams ideally beginning preconception and continuing through the postpartum period. PMID:20424969

Tsiaras, Sarah; Poppas, Athena



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

PubMed Central

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

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



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

PubMed Central

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

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



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

PubMed Central

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

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



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


1. The role of the renin-angiotensin system in the regulation of myocardial contractility is still debated. In order to investigate whether renin inhibition affects myocardial contractility and whether this action depends on intracardiac rather than circulating angiotensin II, the regional myocardial effects of systemic (i.v.) and intracoronary (i.c.) infusions of the renin inhibitor remikiren, were compared and related to the effects on systemic haemodynamics and circulating angiotensin II in open-chest anaesthetized pigs (25-30 kg). The specificity of the remikiren-induced effects was tested (1) by studying its i.c. effects after administration of the AT1-receptor antagonist L-158,809 and (2) by measuring its effects on contractile force of porcine isolated cardiac trabeculae. 2. Consecutive 10 min i.v. infusions of remikiren were given at 2, 5, 10 and 20 mg min-1. Mean arterial pressure (MAP), cardiac output (CO), heart rate (HR), systemic vascular resistance (SVR), myocardial oxygen consumption (MVO2) and left ventricular (LV) dP/dtmax were not affected by remikiren at 2 and 5 mg min-1, and were lowered at higher doses. At the highest dose, MAP decreased by 48%, CO by 13%, HR by 14%, SVR by 40%, MVO2 by 28% and LV dp/dtmax by 52% (mean values; P < 0.05 for difference from baseline, n = 5). The decrease in MVO2 was accompanied by a decrease in myocardial work (MAP x CO), but the larger decline in work (55% vs. 28%; P < 0.05) implies a reduced myocardial efficiency ((MAP x CO)/MVO2). 3. Consecutive 10 min i.c. infusions of remikiren were given at 0.2, 0.5, 1, 2, 5 and 10 mg min-1. MAP, CO, MVO2 and LV dP/dtmax were not affected by remikiren at 0.2, 0.5 and 1 mg min-1, and were reduced at higher doses. At the highest dose, MAP decreased by 31%, CO by 26%, MVO2 by 46% and LV dP/dtmax by 43% (mean values; P < 0.05 for difference from baseline, n = 6). HR and SVR did not change at any dose. 4. Thirty minutes after a 10 min i.v. infusion of the AT1 receptor antagonist, L-158,809 at 1 mg min-1, consecutive 10 min i.c. infusions (n = 5) of remikiren at 2, 5 and 10 mg min-1 no longer affected CO and MVO2, and decreased LV dP/dtmax by maximally 27% (P < 0.05) and MAP by 14% (P < 0.05), which was less than without AT1-receptor blockade (P < 0.05). HR and SVR remained unaffected. 5. Plasma renin activity and angiotensin I and II were reduced to levels at or below the detection limit at doses of remikiren that were not high enough to affect systemic haemodynamics or regional myocardial function, both after i.v. and i.c. infusion. 6. Remikiren (10(-10) to 10(-4) M) did not affect contractile force of porcine isolated cardiac trabeculae precontracted with noradrenaline. In trabeculae that were not precontracted no decrease in baseline contractility was observed with remikiren in concentrations up to 10(-5) M, whereas at 10(-4) M baseline contractility decreased by 19% (P < 0.05). 7. Results show that with remikiren i.v., at the doses we used, blood pressure was lowered primarily by vasodilation and with remikiren i.c. by cardiac depression. The blood levels of remikiren required for its vasodilator action are lower than the levels affecting cardiac contractile function. A decrease in circulating angiotensin II does not appear to be the sole explanation for these haemodynamic responses. Data support the contention that myocardial contractility is increased by renin-dependent angiotensin II formation in the heart. PMID:8851507

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



Choice of cardiac tissue in vitro plays an important role in assessing the risk of drug-induced cardiac arrhythmias in human: Beyond QT prolongation  

Microsoft Academic Search

IntroductionRecently we have demonstrated that to the choice of tissue type is important in identifying IKr and IKs-induced prolongation of the action potential. However, the differential sensitivity of cardiac tissues to other ionic current blockers or modulators is relatively unknown. The aim of the present study was therefore to evaluate tissue-specific effects of different ion channel blockers or activators on

Hua Rong Lu; Eddy Vlaminckx; David J. Gallacher



Rehabilitating elderly cardiac patients.  

PubMed Central

The aging cardiovascular system undergoes many anatomic and physiologic changes. Increased vascular resistance, myocardial "stiffness," abnormalities of rhythmicity of the sinoatrial node, irregular cardiac rhythms, and alterations in heart rate and blood pressure responses are all seen more frequently in older patients. These changes are likely to impair these patients' ability to make the rapid adjustments necessary to maintain cardiac output during exercise and activity. When cardiovascular disease processes are superimposed on the "normal" concomitants of aging, greater alterations in hemodynamic response to exercise activity are noted than usually occur in younger cardiac patients. Exercise testing of older cardiac patients is safe and is usually needed to prescribe an appropriate intensity of exercise activity. The choice of the exercise protocol, the timing of the exercise test in relation to taking prescribed cardiac medication, the choice of exercise equipment, and special considerations for devices such as pacemakers and automatic implantable cardiodefibrillators must be considered before the exercise test is done. Many of these factors and the presence of either silent or overt cardiac symptoms or untoward hemodynamic events will also affect the exercise prescription. Elderly patients usually show substantial functional improvement when participating in a cardiac rehabilitation program and comply well with prescribed exercise. Early educational intervention may be crucial to reducing disability in these patients.

Anderson, J. M.



Preoperative and long-term cardiac risk assessment. Predictive value of 23 clinical descriptors, 7 multivariate scoring systems, and quantitative dipyridamole imaging in 360 patients.  

PubMed Central

A total of 360 patients underwent preoperative cardiac risk assessment using 23 clinical parameters, seven multivariate clinical scoring systems, and quantitative dipyridamole-thallium imaging to predict postoperative and long-term myocardial infarction and cardiac death after noncardiac surgery. There were 30 postoperative and an additional 13 cumulative long-term cardiac events after an average follow-up of 15 months. Clinical descriptors were not useful in predicting the outcome of individual patients. The postoperative and long-term cardiac event rates were 1% and 3.5%, respectively, in patients with normal scans or fixed perfusion defects, and 17.5% and 22% in patients with reversible defects. Using quantitative indices reflecting the amount of jeopardized myocardium, patients could be stratified by dipyridamole imaging into multiple scintigraphic subsets, with corresponding postoperative and 1-year coronary morbidity and mortality rates ranging from 0.5% to 100% (p = 0.0001). Thus, postoperative and long-term cardiac events cannot be predicted clinically, whereas quantitative dipyridamole imaging accurately identifies high-risk patients who require preoperative coronary angiography.

Lette, J; Waters, D; Bernier, H; Champagne, P; Lassonde, J; Picard, M; Cerino, M; Nattel, S; Boucher, Y; Heyen, F



Polymer waveguide output coupler  

NASA Astrophysics Data System (ADS)

Waveguide output couplers fabricated in Norlund Optical Adhesive (NOA) #81 are investigated. The output coupler is implemented using periodic relief gratings on a planar waveguide. Design theory of the coupler is based ont he perturbation approach. Coupling of light from waveguide propagation modes to output radiation modes is described by coupled mode theory and the transmission line approximation of the perturbed area (grating structure). Using these concepts, gratings can be accurately designed to output a minimum number of modes at desired output angles. Waveguide couplers were designed using these concepts. The couplers were fabricated and analyzed for structural accuracy, output beam accuracy, and output efficiency. Applications for these couplers include databus and clock distribution system interfaces requiring coupling to out-of- plane detectors.

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



Cardiac findings in the precompetition medical assessment of football players participating in the 2009 African Under17 Championships in Algeria  

Microsoft Academic Search

Objectives:To screen all players registered for the 8th CAF African Under-17 Championship for risk factors of sudden cardiac death.Design:Standardised cardiac evaluation prior to the start of the competition.Study population:155 male football players from all eight qualified teams; mean age 16.4 (SD 0.68) years (range 14 to 17).Methods:The cardiac evaluation consisted of a medical history, clinical examination, 12-lead resting electrocardiogram (ECG)

C Schmied; Y Zerguini; A Junge; P Tscholl; A Pelliccia; B M Mayosi; J Dvorak



[Anesthetic management for pneumonectomy in a patient with cardiac amyloidosis].  


Cardiac amyloidosis may cause restrictive cardiomyopathy associated with heart failure, conduction disorder and ischemic heart disease. Therefore, patients with amyloidosis require careful hemodynamic monitoring in perioperative period. A 63-year-old man with cardiac amyloidosis was scheduled for pneumonectomy. His transthoracic echocardiography assessment showed a hypertrophic interventricular septum and slight decreased ejection fraction of 55%, but left ventricular (LV) diastolic func