Ventricular Response to a Pressure Load

Abstract

Mongrel dogs, weighing 12 to 25 TCg., were anesthetized with Dial (6 nig./Kg.). The trachea WHS intubated, and appropriate femoral, jugular, and carotid vessels were isolated and eannnlnted as required. Heparin (3.5 mg./Kg.) was administered intravenously. When a change in blond volume was desired, blood (20 cc./Kg.) was withdrawn from, and reinfused into, the femoral artery via a, polyethylene cannula and a pressurized inverted flask containing heparin. Dextrnn was used to replenish blood lost through operative procedures. To modify myocardial contractility, tnetaraininol (Aramine) was infused in 0.9 per cent saline solution via one femoral vein in a mounts sufficient to raise the systolic blood pressure about 20 mm. ITg. Anoxia (with hypercapnia.) was induced by suppressing respiration with added anesthesia. When abrupt changes of cardiac output were desired, arteriovenous fistulae, created by placing large-bore cannulae in adjacent iliac veins and arteries and connecting the ends of the cannulae with plastic tubing, were opened or closed. PRESSURE MEASUREMENTSThe left ventricle was eannulated rctrogradely through the carotid artery and aortic, valve. A con-16. SARNOFF, S.

Experimental myocardial infarction

“…These data were also examined in terms of the maximal developed pressure which the ventricle could generate in the three different study states. Maximal pressure at the plateau of the ventricular function curve is a reflection of "maximum strength" since ventricular contraction is essentially isometric (19 (Fig. 1) Hemodynamic measurements.…”

“…The method of Goodyer et al (19,20) for pressure loading of the left ventricle was chosen because of its reproducibility, suitability for serial studies, and speed with which ventricular function could be tested in the intact, conscious animal. With this method, alterations in heart rate and marked arterial hypotension distal to the obstruction (21) are produced.…”

“…It has been the impression that improvement of left ventricular function occurs during recovery, but this has not been cons stently documented (14,15,17 to left ventricular-developed pressure during transient aortic obstruction (19)(20)(21)(22). In addition, routine hemodynamic measurements were carried out.…”

“…Only the ventricular function curves in which no ventricular arrhythmia occurred (19) were analyzed. Pressure tracings were made using a multichannel photographic recorder (Hewlett-Packard Co., Palo Alto, Calif.).…”

Effect of Hypothermia on High-Energy Phosphate Stores and Contractile Function in Supported Isolated, Blood Perfused Heart

“…The choice of a load test and the expression in terms of PLVP as a function of EDLVP seems perfectly adequate [14,19], the reproducibility for the same heart, parallel changes of these curves with changes of ventricular contractility [14], high correlation coefficient obtained when ventricular function were normalized [19] support the validity of the test.…”