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Notarius C F - - 1996
Central venous pressure (CVP) gives the integral result of changes in cardiac and peripheral factors. Thus, the sudden increase in CVP observed at the onset of dynamic exercise has been attributed to the action of the muscle pump but is also affected by reflex changes in cardiac response. To determine ...
Paterson D J - - 1996
Exercise disturbs cardiac sympathovagal and ionic balance. In arterial blood, vigorous exercise can double plasma K(+), decrease pH by 0.4 unit, and raise catecholamines 15-fold. If any of these changes are experienced at rest, there is an increased risk of arrhythmia and cardiac arrest, yet in exercise they are usually ...
Barton C - - 1996
STUDY OBJECTIVE: To determine whether the computer-derived measures of median frequency or peak amplitude of ventricular fibrillation (VF), obtained by fast Fourier transform of the VF waveform, change during selective aortic arch perfusion in a canine model of cardiac arrest. METHODS: Eight mongrel dogs (including 4 control animals) were sedated, ...
Pianosi P - - 1996
Electric bioimpedance has been used to measure cardiac output for decades. Improvements in modeling and microprocessor technology have spawned newer generations of such devices. This method would be especially useful in children, in whom the use of invasive methods is limited. We tested a device (ICG-M401, ASK Ltd.) in 30 ...
Pianosi P - - 1996
Previous studies comparing cardiac output (Q) and stroke volume (SV) between cystic fibrosis (CF) patients and control subjects have shown conflicting results: some found lower SV in CF patients with severe airflow limitation, and others showed no difference between CF and control subjects. Methodologic problems could explain these discrepant findings. ...
Halliwill J R - - 1996
The occurrence of a sustained vasodilation and hypotension after acute, dynamic exercise suggests that exercise may alter arterial baroreflex mechanisms. Therefore, we assessed systemic hemodynamics, baroreflex regulation of heart rate, and cardiac vagal tone after 60 min of cycling at 60% peak oxygen consumption in 12 healthy, untrained men and ...
Reisner C - - 1996
BACKGROUND: Continuous nebulization is a safe and practical method of administration of beta 2-adrenergic agonists during acute asthma. There are essentially two types of continuous nebulizer systems; one utilizes a large volume nebulizer and the other a small volume nebulizer attached to a constant volume infusion pump. OBJECTIVES: We compared ...
Rådström M - - 1995
Bolus doses of ephedrine are often used by anaesthesiologists for intraoperative hypotension. This randomized single-blind cross-over study was designed to simultaneously evaluate circulatory, respiratory and metabolic effects of intravenously given ephedrine in 12 healthy male volunteers. Oxygen uptake and carbon dioxide excretion were measured with indirect calorimetry and non-invasive transthoracic ...
Thrush D - - 1995
OBJECTIVE: Cardiac outputs were determined with continuous thermodilution, bolus thermodilution, and the Fick method during pharmacologically varied hemodynamics. DESIGN: Prospective comparison of techniques. SETTING: University animal laboratory. PARTICIPANTS: Swine. INTERVENTIONS: Swine were anesthetized, tracheally intubated, and instrumented to measure continuous (QTDC) and bolus (QTDB) thermodilution cardiac outputs and sample arterial ...
Zhang S - - 1995
We performed single-breath tests in closed-chest, paralyzed, and anesthetized dogs (6 with bilateral vagotomy and 6 with intact vagi) with the heart beating and during cardiac arrest. Repeated cardiac arrest was achieved by ventricular fibrillation and subsequent defibrillation. Twenty-four single-breath tests per dog were performed in combinations of three inspiratory ...
Leyh R G - - 1995
Bicaval orthotopic cardiac transplantation leaving the right atrium intact has been introduced recently into clinical practice as an alternative to the standard method. To determine the effect of the surgical technique, 27 patients were studied at rest and supine exercise 19 +/- 5 months after bicaval orthotopic cardiac transplantation (group ...
Nishio M L - - 1995
Existing literature provides an equivocal picture of the behavior of mitochondrial synthesis during the time course of cardiac hypertrophy. Therefore, we examined the effect of cardiac hypertrophy on mitochondrial cytochrome c oxidase (CYTOX) activity, the content of CYTOX subunit VIc mRNA, and the expression of molecular chaperones. Adult male Sprague-Dawley ...
McConnell T R - - 1995
PURPOSE: Simultaneously measured oxygen uptake (VO2) and Doppler echocardiography could verify if an alteration in the VO2 response to progressive and constant load work is due to reduced cardiac output. METHODS: The study group consisted of nine patients after acute myocardial infarction (MI), five age-matched healthy subjects (HE), and five ...
Hsia C C - - 1995
In dogs during exercise, respiratory rate can reach 200 breaths/min, blood temperature can exceed 42 degrees C, and hematocrit can approach 60%. To determine whether these changes significantly affect the measurement of cardiac output by the acetylene rebreathing method (QcRB), we compared estimates of QcRB with those measured by thermodilution ...
Espersen K - - 1995
Simultaneously measured cardiac output obtained by thermodilution (TD), transcutaneous suprasternal ultrasonic Doppler (DOP), CO2-rebreathing (CR) and the direct Fick method (FI) were compared in eleven healthy subjects in a supine position (SU), a sitting position (SI), and during sitting exercise at a workload of 50 W (EX). The agreements between ...
Hadjis T - - 1995
OBJECTIVE: To determine the intra- and interobserver reproducibility of Doppler-derived ascending aortic flow velocity measurements at rest and during upright exercise of increasing intensity; and to determine the relationship between Doppler-derived measurements and cardiac output obtained by the indirect Fick carbon dioxide rebreathing method in the same conditions. SUBJECTS: Twenty ...
Fahrenbach M C - - 1995
The effects of doxazosin or atenolol on exercise capacity in 15 male distance runners (mean age +/- SD 43 +/- 10 years) were compared in a double-blind, crossover study. Subjects performed a maximal treadmill test and a timed 2-mile run before and after each drug treatment. Cardiac output was determined ...
Sone R - - 1995
The effects of the phase of respiration on the response of respiratory cardiac cycle variability to sensory stimulation were studied in five healthy young male subjects. Transcutaneous electrical stimulation of the ulnar nerve or hand-grip exercise was applied during inspiration or expiration. Although both electrical stimulation and hand-grip exercise depressed ...
O'Neill M - - 1995
Cardiovascular performance was studied in 18 alpha-chloralose anaesthetized pigs when arterial potassium ([K+]a) was raised to levels observed in heavy exercise. The effects of hyperkalaemia were then studied during cardiac sympathetic nerve stimulation or during an infusion of noradrenaline. Elevation of [K+]a up to ca. 10 mM caused a progressive ...
Fagard R H - - 1995
To study the influence of gender on peak oxygen uptake and on the hemodynamic response to dynamic exercise in essential hypertension, 45 male and 45 female patients, matched for age and blood pressure, were studied. Blood pressure was measured intra-arterially and cardiac output by the direct oxygen Fick method. Anthropometric ...
Stebbins C L - - 1995
Angiotensin II (ANG II) is a potent vasoconstrictor of splanchnic and renal resistance vessels. Because ANG II increases during exercise and blood flow in the splanchnic and renal circulations decreases, we tested the hypothesis that ANG II plays a role in arterial blood pressure and regional blood flow responses to ...
Sheriff D D - - 1994
The distribution of cardiac output (CO) between compliant and noncompliant organs is an important determinant of the slope of the relationship predicted between CO and right atrial pressure (RAP). However, curves relating CO to RAP at rest are shifted rightward (higher CO) and upward (higher RAP) by exercise with no ...
Levin H R - - 1994
Left ventricular assist devices (LVADs) increasingly are being used as a bridge to transplantation. We studied changes in New York Heart Association class, mean arterial pressure, resting cardiac output, end-organ function, exercise oxygen consumption, and exercise cardiac output in 12 LVAD recipients. In addition, resting levels of neurohormonal factors were ...
Myers J N - - 1994
Exercise testing is a valuable tool to assess cardiopulmonary function. It can define the limits of performance in an athlete or the functional capabilities of the patient with heart disease. Exercise capacity is determined most accurately by ventilatory oxygen uptake, which is defined by maximal cardiac output and the ability ...
Toska K - - 1994
The immediate cardiovascular responses at the onset of supine dynamic leg exercise were studied by noninvasive methods in healthy humans. Total peripheral conductance (TPC), heart rate, and cardiac output increased very rapidly at the onset of exercise. Mean arterial pressure (MAP) showed a moderate anticipatory increase during a 10-s countdown ...
Constable P D - - 1994
The inotropic effects of hypertonic saline (HS) and hyperosmotic dextrose (HD; 2,400 mosmol/l, 4 ml/kg) were determined in normovolumic, chloralose-anesthetized, intact (n = 14) and autonomically blocked (n = 8) dogs. Solutions were infused intravenously over 3 min. HS and HD rapidly increased preload in both intact and autonomically blocked ...
Kollai M - - 1994
Adolescent anorexia nervosa, a psychiatric disease with high mortality, is often associated with bradycardia. We studied the vagal control of sinus node function in anorexic subjects, to investigate the mechanism of anorexic bradycardia. Cardiac vagal tone was determined in a group of 11 adolescent anorexic girls and in 11 age- ...
Kurdibaylo S F - - 1994
Two hundred and thirty subjects with various levels of upper and lower limb amputation were examined with regard to cardiac and respiratory functions. The subjects were examined at rest and in balanced wheelchair ergometer testing. Noncontinuous step-by-step increased loading was performed. The data given are for age-group 20-40 who sustained ...
Pan K M - - 1994
Methods were developed for isolation of bovine cardiac titin in the apparently full-sized T1 form. The pure protein could be obtained either in the denatured state after chromatography of myofibril extracts on Sephacryl S-1000 or in the native state using hydroxylapatite chromatography. Titin-specific chicken polyclonal antibodies against denatured titin stained ...
Abe Y - - 1994
A total artificial heart (TAH) goat survived for 360 days on the new automatic control method (1/R control), in which the cardiac output of the TAH can be controlled through the cardiovascular center by making it function by reflecting the beta-adrenergic reaction in peripheral vascular resistance. This is thought to ...
Haskell W L - - 1994
Physical activity performed by patients with coronary heart disease is a two-edged sword. A number of biological changes produced by regular exercise may reduce the risk of future cardiac events, while the increase in cardiac work produced by this same exercise can predispose the patient to sudden cardiac death. Data ...
Perrault H - - 1994
After a century of research reports, the notion of exercise-induced cardiac hypertrophy is still an expected adaptation to regular exercise training. Experimental evidence reported both in animals and in humans over the past 3 decades suggests, however, that this conclusion may not be totally warranted. Data from 20 years of ...
Sato S - - 1994
Using 14 mongrel dogs, we investigated the correlation between arteriovenous differences of PCO2 (AVD-CO2) and cardiac output (CO) during CPR. Ventricular fibrillation was induced by an electrical current and the respirator was stopped for 5 min. Cardiopulmonary resuscitation (CPR) was performed during the next 10 min and CO was measured ...
Eriksen M - - 1994
Cardiac output and superior mesenteric arterial flow in five healthy young men were followed using Doppler ultrasound techniques at rest and during 4 min bouts of bicycle exercise in both a pre- and a post-meal situation. The meal given was mixed and heavy, with an energy content (related to body ...
Barthélémy G - - 1994
We have compared the ability of a new calcium channel-blocking agent, fantofarone (SR 33557), to modify the cardiovascular function in anesthetized dogs, with that of nifedipine. Administration of fantofarone (50 micrograms/kg, i.v.) resulted in substantial changes in cardiac function, such that stroke volume was increased by 40% (p < 0.05) ...
Nugent A M - - 1994
Cardiac output was measured in 11 patients undergoing routine cardiac catheterization using a carbon dioxide rebreathing technique and compared with cardiac output measured by direct Fick and thermodilution. The carbon dioxide rebreathing technique gave consistently lower values for cardiac output than the other two methods (mean difference -0.73, 95% CI ...
Williamson J W - - 1994
To determine effects of aerobic exercise training on individual contributions of the right and left carotid sinus baroreflex control of the cardiac interval, heart rate [expressed as R-R Interval (RRI)] and mean arterial pressure (MAP) responses were elicited by pulsed trains of neck suction and pressure in exercise trained (ET ...
O'Hagan K P - - 1994
Activation of cardiac sensory receptors with vagal afferents can result in inhibition of sympathetic outflow to the peripheral circulation. This study investigated whether the regulation of renal sympathetic nerve activity (RSNA) during dynamic exercise was modulated by cardiac sensory receptors. RSNA, blood pressure, and heart rate were measured in seven ...
Leyk D - - 1994
Owing to changes in cardiac output, blood volume distribution and the efficacy of the muscle pump, oxygen supply may differ during upright and supine cycle exercise. In the present study we measured, in parallel, circulatory (heart rate, stroke volume, blood pressure) and metabolic parameters (oxygen uptake, lactic acid concentration [la]) ...
Kiss D - - 1994
The present study examined possible short-term effects of the heat stress during sauna bathing on gas exchange, especially in correlation with changes in cardiac output. The results obtained are as follows: (1) The heat stress of sauna bathing caused a slight but not significant increase in diffusion capacity (p = ...
Welch E - - 1994
Since cardiac output measured by the noninvasive pulsed Doppler technique has not been well correlated to results from the invasive thermodilution or Fick methods in neonates, the three methods were evaluated in 6 sedated newborn piglets (age < or = 7 days, weight 1.5 +/- 0.7 kg) in room air ...
Broeder C E - - 1993
The effects of a nonselective beta-adrenergic blocking agent with (pindolol) and without (propranolol) intrinsic sympathomimetic activity properties, compared with placebo-controlled conditions, on metabolic and cardiorespiratory function during long-duration (2 hours) physical activity were examined. After initial cardiorespiratory testing, subjects performed 2-hour walks at 25 and 45% of maximal oxygen consumption ...
Collins H L - - 1993
Naloxone eliminates postexertional hypotension (PEH) in human and animal models. The effect of naloxone on sympathetic activity during hemorrhage and generation of arterial baroreflex function curves can be stimulated by blockade of cardiac afferent receptors. We tested the hypothesis that cardiac afferent blockade would eliminate PEH in eight spontaneously hypertensive ...
Schandry R - - 1993
The mediation of heartbeat perception by cardiodynamic parameters was investigated by experimentally introducing changes in heart performance. Twenty-five subjects (14 women, 11 men) underwent bicycle ergometric exercises (0-75 W) at different tilt angles (90 degrees-0 degree). After each of the 31 tilt/exercise phases, the following measures of cardiac performance were ...
Patterson R - - 1993
A study was conducted on 26 healthy male adults comparing the stroke volume (SV) and cardiac output (CO) measured with green dye and impedance cardiography in supine, sitting and during 50 W bicycle exercise. The impedance voltage pick-up electrodes were modified from the standard band location and placed at the ...
Miles D S - - 1993
Impedance cardiography has been used over the last 30 years to measure stroke volume on a beat-by-beat basis. Cardiac output has been successfully measured with either upper or lower body exercise during light or moderate workloads. With strenuous exercise, movement artifacts severely limit the acquisition of a quality impedance cardiogram. ...
Adamson P B - - 1993
Prior studies have shown that in vivo systemic administration of pertussis toxin in conscious dogs catalyzes ADP ribosylation of Gi and G(o) proteins, which attenuates intracellular transduction of muscarinic receptor activation. We tested the hypothesis that this impairment may result in the alteration of the following indexes of cardiac vagal ...
Nakanishi N - - 1993
To determine whether continuous Fick cardiac output measurement is applicable to exercise testing, cardiac output data obtained by the continuous Fick method (Qcf) during exercise were compared with data obtained by the thermodilution method (Qth). Seventeen patients with old myocardial infarction underwent a 1-min or 3-min incremental exercise test (protocols ...
O'Neill M - - 1993
A rapid increase in arterial plasma potassium concentration to values seen during intense exercise depresses cardiac function at rest. Increasing the cardiac concentration of noradrenaline by right-sided sympathetic stimulation in eleven anaesthetized pigs significantly augmented cardiovascular performance during hyperkalaemia, while electrical pacing of the right atrium at equivalent rates to ...
Sheriff D D - - 1993
At rest, central venous pressure (CVP) falls when cardiac output (CO) rises. This can be attributed to flow-dependent redistribution of blood volume from central to peripheral blood vessels. In contrast, CVP rises during dynamic exercise despite a rise in CO. Therefore peripheral circulatory changes during exercise must counteract the factors ...
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