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The systemic hemodynamics at rest, and the response to graded exercise in the sitting position were examined in 33 men with mild untreated arterial hypertension, and compared with the results from a control group of 59 normotensive men. Hypertensive men without retinal vascular changes were characte

The authors studied the effect of N-[β-(p-1-hydroxypropyl)phenoxyethyl]-1-phenyl-2-aminopropane (I) on respiration and general metabolism and on systemic hemodynamic in the chloralosed dog. Under the

The role of the β-adrenergic system in the adaptation of cardiac output and coronary flow to exercise was investigated in 9 conscious dogs. Some of the experiments were carried out in dogs with experimental atrio-ventricular block and paced heart rates.

The influence of acute changes in systemic hemodynamics on the rate of oxygen utilization by the left ventricle has been studied in intact anesthetized dogs. Certain types of hemodynamic changes caused reproducible alterations in the relationship between oxygen consumption of the left ventricle and its external mechanical work. The relationship of left ventricular minute oxygen consumption to the product of mean systolic aortic pressure and systolic ejection period per minute was constant over an extreme range of varied types of hemodynamic alterations. Changes in oxygen consumption were proportionately less than concomitant changes in heart rate. These findings are in accord with previous studies of isolated heart preparations.

Excerpt Many studies of the systemic hemodynamics of arterial hypertension have been done, both in the experimental animal and in man, and these have recently been reviewed by Fries.1The specific d...

In order to examine the influence of the sympathetic innervation on coronary and systemic hemodynamics, dogs have been chemically sympathectomized by repeated administration of 6-hydroxydopamine i.v. This procedure results in a selective degeneration of peripheral nerve endings (8). In adult animals the adrenal medulla remains unaffected, but may show compensatory hyperactivity (6). Since in the adult animal the sympathetic ganglionic cells and axons remain intact, regeneration of sympathetic nerve endings takes place within a few weeks (4). This technique allows one to obtain data before and after sympathectomy in the same animal within a short period of time and without the additional trauma and complications due to surgical denervation.

Coronary and systemic hemodynamics were compared in 15 normal men and 15 normal women. Systemic hemodynamics were very similar. The women had 26.5 per cent greater coronary flow and 19.6 per cent more oxygen consumption/100 Gm. of left ventricular myocardium. Their calculated coronary vascular resistance was 35 per cent less. Significant negative correlations between coronary flow and calculated heart weight, and between cardiac oxygen consumption and calculated heart weight, as well as between coronary flow and hematocrit probably explain the differences in part. Whether hormonal or anatomic differences are also significant is not known.

Nineteen observations were made in 12 patients with early essential hypertension. The comparative effects upon mean arterial blood pressure, cardiac index, and total peripheral resistance of the acute and long-term administration of chlorothiazide were studied. With acute administration of the drug, a 10 per cent drop in mean arterial blood pressure, a decrease of 18 per cent in cardiac index, and an increase of 7 per cent in peripheral resistance were observed. With long-term administration, a decrease of 21 per cent in mean arterial blood pressure, an increase of 4 per cent in cardiac index, and a drop of 26 per cent in peripheral resistance were found. The conclusion is drawn that reduction of mean arterial blood pressure with acute administration of chlorothiazide is due to decrease in cardiac output, whereas with long-term use it is due to reduction in total peripheral resistance.

Isoproterenol hydrochloride and lactated Ringer's solution were employed in the treatment of low perfusion acidosis produced by acute blood volume reduction in 27 dogs. Their relative effectiveness was determined by measuring oxygen consumption, cardiac rate and output, and blood pressure. Neither isoproterenol nor lactated Ringer's solution produced significant improvement in either cardiac function or oxygen uptake. Significant improvement did, however, result when lactated Ringer's solution and isoproterenol were used in combination.