In anesthetized rats under artificial respiration, intravenous infusion of nisoldipine (0.1 mg/kg x min) caused significant decreases in blood pressure, heart rate, cardiac output and peripheral resistance. The animals died 54.7 +/- 11.1 min after initiation of the infusion. The electrocardiogram showed sinus bradycardia, increasing AV blockade and displacement of ...

1. An improved Doppler ultrasound technique was used to measure stroke volume (SV) and cardiac output (CO) on a beat-to-beat basis in a group of supine humans before, during and after periods of standardized, rhythmic exercise, involving the quadriceps muscle groups on both sides. The development of CO on such ...

We compared metabolic and cardiovascular responses to aerobic exercise with the direct Fick technique in women during and after pregnancy. Seven subjects were studied at 37 weeks' gestation and again 12 weeks postpartum. All were tested at rest and during four sequential exercise bouts consisting of 5 minutes at each ...

To determine the role of cardiac reflexes in mediating exercise hyperpnea, we investigated ventilatory responses to treadmill exercise in seven calves with artificial hearts and seven controls. In both groups, the ventilatory responses were adequate for the metabolic demands of the exercise; this resulted in regulation of arterial PCO2 and ...

We examined the cardiovascular response at rest and during upright cycle exercise in nine women during pregnancy (25.6 +/- 3.0 weeks' gestation) and at 2 months (8.8 +/- 1.8 weeks) and 7 months (30.0 +/- 2.5 weeks) post partum. Antepartum resting cardiac output, heart rate, and stroke volume were higher, ...

Labetalol, a combined alpha- and beta-blocking agent, was administered to 12 patients (mean age 55 years) with idiopathic dilated cardiomyopathy to examine its effects on symptomatology and exercise performance. Studies were performed before treatment, after 8 weeks of placebo, and after 8 weeks of labetalol therapy in a randomized, crossover, ...

This study was designed to determine whether cardiac vagal afferents exert an inhibitory influence on increases in regional vascular resistance during exercise and to determine whether endurance exercise training enhances the inhibitory influence of cardiac vagal afferents. We measured changes in regional vascular resistance in 12 rabbits at rest and ...

Cardiac output was measured by the thermodilution method in three young harbor seals, at rest and while swimming up to the maximum effort for which they could be trained. Stroke volume was determined by counting heart rate simultaneously with determination of cardiac output. Cardiac outputs varied widely between surface breathing ...

The application of the thermodilution method in conditions associated with variations in blood flow implies a misuse of the Stewart Hamilton equation. Therefore, we studied the reliability of the thermodilution method for the estimation of mean cardiac output (CO) during mechanical ventilation in patients (n = 9). Variation of the ...

This software program adds two very interesting data to the usual results of exercise testing: an estimation of cardiac output according to the most recent validations and a reliable estimation of alveolar ventilation. The main advantage of this additional ventilatory and cardiovascular information using the same data: end-tidal PCO2.

Cardiac haemodynamics are deranged in chronic heart failure but fail to predict the exercise capacity of the patient. Cardiac power output is a descriptor of cardiac function derived from preload, blood pressure and cardiac output. Forty-one patients with moderately severe and severe chronic heart failure were exercised on a cycle ...

The influence of cardiac afferents on the arterial baroreflex regulation of renal sympathetic nerve activity (RSNA) was examined before and after an endurance training program. The 8-wk endurance exercise training program resulted in an exercise-induced bradycardia (decreased heart rates at rest and during a graded exercise test). At rest (210 ...

Substantial evidence has accumulated that in the human heart both beta1- and beta2-adrenoceptors coexist. As a rule, the amount of beta2-adrenoceptors is higher in the atria (about 30% of the total beta-adrenoceptor population) than in the ventricular myocardium (about 20%). Both beta1- and beta2-adrenoceptors couple to adenylate cyclase and mediate ...

The central and peripheral haemodynamic effects of a modest meal were investigated in healthy volunteers at rest and in response to submaximal exercise. The meal increased heart rate, cardiac output, oxygen consumption, carbon dioxide production, and minute ventilation at rest and during exercise. The effects of food were additive to ...

Congestive heart failure occurs when myocardial dysfunction is advanced. Although clinical manifestations and diminished functional capacity can be traced back to the poor cardiac contractile state, there are major modifying influences from a complex series of compensatory responses. These particularly involve the heart, vessels, kidneys, sympathetic nervous system, the renin-angiotensin ...

To determine the effect of the Fontan operation on exercise tolerance and cardiorespiratory response to exercise, we compared the preoperative and postoperative responses to graded exercise to maximal effort in 20 patients who underwent a modified Fontan procedure. The mean interval between preoperative and postoperative exercise testing was 1.8 years. ...

This symposium is concerned with the use of resistive exercise in cardiac and coronary prone populations. In the past, these populations have been refrained from resistive exercise. However, recent studies suggest that this form of exercise is safe and has favorable effects on physical fitness, cardiac risk factors such as ...

The cardiac denervation produced by heart transplantation modifies the physiological response to exercise. The cardiorespiratory and sympathoadrenal response of seven "healthy" orthotopic heart transplant recipients was compared to seven age matched normal subjects during progressive dynamic exercise. The initial venous noradrenaline concentration tended to be higher in the transplant group, ...

Over the past few years, a metabolic rate meter has been introduced for easy measurement of oxygen consumption. However, its accuracy is unproved. In 40 patients (26 men, 14 women, ages 34 to 73 years), cardiac output was measured simultaneously by thermodilution and the Fick method using the metabolic rate ...

The side effects associated with recombinant interleukin 2 administration, including systemic hypotension and a vascular leak syndrome, may limit therapy before reaching maximum doses of this innovative and promising treatment for cancer. In an attempt to reverse this hypotension without decreasing cardiac output and systemic oxygen delivery (DO2), we studied ...

The author reviews the haemodynamic changes in response to exercise, autonomic nervous blockade and food take, Left ventricular (LV) volume changes are most pronounced during mild exercise, whereas an increase in heart rate is the primary determinant for the increase in cardiac output during mild to heavy exercise. After autonomic ...

The multidimensional pathophysiology of septic shock is poorly understood and treatment modalities are controversial. The present study evaluates the relative importance of three therapeutic measures: antibiotics (trimethoprim and sulphamethoxazole [TS]); fluid infusions (lactated Ringer's solution [RL] and 3% albumin [Alb]), and pharmacologic doses of corticosteroids (CS) (dexamethasone [DM]), using central ...

This study examines the influence of complement on systemic hemodynamics following severe thermal injury in rats. Animals were injected intraperitoneally at t = -36 and t = -24 hours with either cobra venom factor (20 units/kg/dose; n = 56) to delete circulating complement or with saline alone (n = 64). ...

Animal exercise studies have shown a self-regulated change in cardiac output (CO) with the J-7 total artificial heart (TAH). A 49-year-old, 75 kg patient received a J-7-70 TAH as a bridge to transplant. During bicycle exercise, the TAH heart rate, drive pressures, percent systole, and vacuum were unchanged. Cardiac output ...

Cardiopulmonary exercise testing is an objective method of assessing the functional capacity of a patient. In contrast to clinical assessment and resting investigations, exercise testing is useful in detecting early changes in patients with cardiac or respiratory disease. Although a number of different types of ergometers can be used for ...

The cardiovascular actions of a renin inhibitor, U-71038 (Boc-Pro-Phe-N-MeHis-Leu psi [CHOHCH2]Val-Ile-Amp), and of an angiotensin converting enzyme (ACE) inhibitor, captopril, were determined in conscious sodium-depleted cynomolgus monkeys. Cardiac output was measured with a thermodilution technique. The hypotension induced by U-71038 was associated with a significant reduction in total peripheral resistance ...

The acute effects of 10 mg of oral nisoldipine on hemodynamics, oxygen transport and metabolism, and distribution of cardiac output, at rest and during semiupright bicycle exercise, were evaluated in 10 men with effort angina receiving long-term beta 1 blockade. Cardiac output and leg blood flow were measured using the ...

The haemodynamic responses to isometric exercise of eight recipients of orthotopic heart transplants and eight healthy controls were studied. Each performed sustained exercise at 30% of maximal voluntary contraction for three minutes on a handgrip dynamometer. Cardiac output was measured by combined Doppler and cross sectional echocardiography before exercise and ...

Movement from the supine to the upright position brings about the transfer of blood from the upper to the lower body. Cardiac output and central arterial pressures are reduced causing, in the normal subject, a reflex increase in sympathetic and a decrease in parasympathetic activity. Increased sympathetic activity facilitates cardiovascular ...

Eight mildly to moderately hypertensive subjects free of any antihypertensive medications and on a normal salt diet performed maximal supine arm exercise. Before starting the exercise, a right-sided cardiac catheterization was performed to measure hemodynamic parameters before and during exercise. All patients had normal increases in cardiac output for the ...

Previous studies have documented systolic blood pressure differences in response to dynamic exercise when blacks were compared with whites. This study was performed to validate these data and to determine if the cardiac output and systemic vascular resistance responses to exercise are different in a biracial population of 10-year-old boys. ...

We examined the hemodynamic factors associated with the lower maximal O2 consumption (VO2max) in older formerly elite distance runners. Heart rate and VO2 were measured during submaximal and maximal treadmill exercise in 11 master [66 +/- 8 (SD) yr] and 11 young (32 +/- 5 yr) male runners. Cardiac output ...

Theophylline (0.1, 0.3 mM) produced a positive inotropism which was maximum by 15 min but was partially or completely absent by 45 min. The mechanism for this response was investigated using post-rest potentiation and positive staircase, phenomenon associated with the sarcoplasmic reticulum and sarcolemma, respectively. Staircase was enhanced at 15 ...

During an acute bout of dynamic exercise, cardiac output increases in direct proportion to the increase in oxygen uptake. The mechanisms by which the cardiac output is increased during exercise may differ between men and women. The increased blood flow is distributed to the exercising skeletal muscle, to the myocardium, ...

Photometrically measured values of O2-saturation (SO2) were compared with SO2 predictions on the basis of the equations proposed by Heck, Kelman, Lutz, Marsoner, Severinghaus, and Siggaard-Andersen on 1350 occasions. Capillary, venous and mixed venous blood samples from 23 healthy subjects and 30 patients, suffering from cardio-pulmonary diseases were analyzed at ...

A computerized continuous wave Doppler instrument was used to monitor changes in cardiac output and stroke volume during supine symptom limited graded bicycle exercise in 30 subjects. Eight patients were studied before and after coronary artery bypass graft (CABG) and were found to have patent grafts (group 1). Six patients ...

Congenital heart defects arise in approximately 1% of all live births, independent of ethnic and geographical considerations. With the development of new surgical procedures and current technologies a large number of these heart lesions can be surgically corrected in infancy. In the majority of cases patients evaluated some 10 to ...

Cardiac output was determined by impedance cardiography (Q(imp)) and a rebreathing method (Q(reb)) during exercise of loads up to 90 W. The correlation between Q(imp) and Q(reb) was generally good, but it was found in two of four subjects that Q(imp) was slightly lower than Q(reb) at the higher exercise ...

To estimate the accuracy of cardiac output measured by continuous wave Doppler echocardiography from the suprasternal notch and the utility of this method for evaluating left ventricular function during dynamic exercise, simultaneous thermodilution and Doppler cardiac output were measured in 34 patients with coronary artery disease during multistage ergometer exercise ...

Correction of a base deficit with hypertonic sodium bicarbonate (NaHCO3) according to the formula 0.3 x body weight (kg) x BE may overestimate the real demands, especially during shock and cardiopulmonary resuscitation (CPR). Life threatening alkalosis and osmolal poisoning may be the consequence. As an explanation, the possibly impaired functional ...

Ventilation and cardiac output in response to four different exercises, namely, volitional pedalling using a bicycle ergometer with a very mild (7 Watt) load, passive pedalling, electrically-induced isometric twitches of one leg, and voluntary twitches simulating the previous electrical twitches, were measured simultaneously during the transient phase from rest. Cardiac ...

A modification of the Farhi one-step rebreathing technique (1) is described for determining submaximal exercise cardiac output (Q). Factors critical in the estimation of Q are initial rebreathing bag volume and constant bag volume during the maneuver. By substituting a high flow rate analyzer (500 ml.min-1) for the recommended low ...

Tribulin (endogenous monoamine oxidase inhibitor/benzodiazepine receptor binding inhibitor) output was measured in the urine of 18 patients with post-traumatic stress disorder (PTSD) and 13 controls. The level of the two inhibitory activities was highly significantly correlated in the group as a whole. There was no difference between output of either ...

The purpose of these experiments is to see if reflex nervous hyperventilation obtained by passive limb movements in man is a consequence of the activation of a direct ascending nervous pathway from mechanoreceptors of moving limbs to respiratory centres, or if it is the consequence of a primary enhanced cardiodynamic ...

The present study was carried out 1) to compare blood flow in the costal and crural regions of the equine diaphragm during quiet breathing at rest and during graded exercise and 2) to determine the fraction of cardiac output needed to perfuse the diaphragm during near-maximal exercise. By the use ...

After the Mustard operation, patients have reduced exercise tolerance, abnormal right and left ventricular responses to exercise and cardiac rhythm disturbances. The cardiovascular response to exercise was measured noninvasively in 19 patients from 4.5 to 20 years (mean 10.3) after operation. Mean work performed and maximal oxygen uptake for the ...

The literature dealing with sudden cardiac death in relation to exercise, particularly sport, is reviewed. The exact incidence of unexpected sudden cardiac death during physical activity in persons previously presumed healthy is difficult to determine due to the wide variation in reporting methods; by all indications, it is extremely low. ...

The nervous regulation of heart rate and stroke volume in the Atlantic cod Gadus morhua was investigated both in vivo, during rest and exercise, and in vitro. The cholinergic and adrenergic influences on the heart were estimated in experiments with injections of atropine and sotalol. At rest the cholinergic and ...

Six patients with chronic atrial fibrillation (AF) took single doses of digoxin, verapamil and diltiazem, alone and in combination. Three hours after dosing, resting and post-exercise heart rate, exercise tolerance and resting and post-exercise cardiac output were measured. Post-exercise heart rates ranged from 167 bpm (after placebo) to 122 bpm ...

No control method has yet been established for the total artificial heart (TAH) during exercise. As the simple intrinsic control method does not significantly increase cardiac output (CO), this study attempted to develop a new TAH control method that increases the CO during exercise in a manner similar to a ...