Stanley J. Sarnoff

Ventricular Function I. Starling's Law of the Heart Studied by Means of Simultaneous Right and Left Ventricular Function Curves in the Dog

Starlings law of the heart has been studied in the dog with a complete circulation with the continuous registration of cardiac output, and atrial and arterial pressures. From this data ventricular function curves were constructed. In any given physiologic state there was a consistent and reproducible correlation between atrial pressure and ventricular stroke work on the same side. The classically conceived descending limb did not occur in the normal heart. The concept of a family of Starling or ventricular function curves adds a third dimension to the adaptive capacity of the heart as put forth by Frank and Starling.

Ventricular function. II. Quantitative relationship between coronary flow and ventricular function with observations on unilateral failure.

Left main coronary artery blood flow, cardiac output and pressures in the pulmonary artery, the aorta and both atria were continuously recorded in the dog. Restriction of left coronary flow increased left atrial pressure substantially, but right atrial pressure only slightly; left ventricular work, cardiac output and arterial pressure fell markedly. During restriction of left coronary flow, the left ventricular function curve (modified Starling curve), which does not normally show a descending limb even at high filling pressures, developed a pronounced descending limb. Unilateral ventricular failure was demonstrated.

The Surgical Relief of Aortic Stenosis by Means of Apical—Aortic Valvular Anastomosis

A means has been devised whereby the aortic valve can be effectively by-passed. Left ventricular blood leaves via the apex through a lucite tube in continuity with a modified Hufnagel valve and then enters the thoracic aorta. In dogs so treated the ascending arch of the aorta may be totally and permanently occluded without apparent impairment of the circulation. Postoperatively these dogs run, jump and swim and are not readily distinguishable from normal dogs. The entire ventricular manipulation is completed in 30 to 60 seconds. The applicability of this procedure to the alleviation of aortic stenosis in man is discussed.

Ventricular function: role of the pericardium in regulation of cardiovascular hemodynamics.

The influence of the pericardium on cardiovascular phenomena has been examined and evaluated in the light of both ventricular function (modified Starling) curves and pressure-volume relationship of the pericardium. When the left ventricle is stressed, as by an increased aortic resistance, it dilates. The resulting pericardial tension limits right ventricular diastolic expansion and right ventricular work. By this mechanism pulmonary blood volume and pressures are kept at lower levels than would otherwise be present. The pericardium also protects against ventriculo-atrial regurgitation which may account for the observed descending limb of the classically conceived Starling curve.

Ventricular Function V. The Circulatory Effects of Aramine; Mechanism of Action of "Vasopressor" Drugs in Cardiogenic Shock

The cardiovascular effects of a new, long-acting, sympathomimetic amine, Aramine, are described. Cardiac output, aortic pressure, coronary flow, and ventricular stroke work rise while atrial pressures fall. A sustained increase in myocardial contractility is produced and the myocardium does not require more coronary flow per unit of ventricular work after its administration. The circulatory effects of ventricular failure produced by restricting coronary flow are reversed by the drug. The authors seriously question the premise that the ideal agent for the management of cardiogenic shock should act solely on the peripheral vascular bed.

Graded reduction of arterial pressure in man by means of a thiophanium derivative (Ro 2-2222); preliminary observations on its effect in acute pulmonary edema.

The authors describe the use of a ganglionic blocking agent which acts almost entirely as a peripheral vasodilator with minimal side effects in man. This substance acts almost instantaneously when given intravenously, with the depressor effect quantitatively controlled by regulating the infusion rate without tachyphylaxis over several hours. Depressor effect of the drug disappears 2 to 15 minutes after stopping the infusion and is blocked promptly by intravenous ephedrine, neosynephrine or norepinephrine. The authors discuss its use in the treatment and elucidation of the basic mechanisms of acute pulmonary edema.

The Potter electroturbinometer; an instrument for recording total systemic blood flow in the dog

The flowmeter described is a turbine which can be driven by the bloodstream. In the turbine is a magnet which induces a recordable signal in an adjacent coil. The flowmeter records pulsating flow as well as steady flow; it is insensitive to temperature and wide variations of blood viscosity. The pressure drop is rather high. The baseline and calibration are steady over long periods of time. The flowmeter has been successfully used for continuously recording the systemic output in the dog.

Elevation of left auricular pressure in relation to ammonium pulmonary edema in the cat.

Summary (1) Ammonium chloride was administered intraperitoneally to 12 cats under sodium pentobarbital anesthesia with measurement of left auricular, femoral arterial, and vena caval pressures. (2) Left auricular and vena caval pressures rose significantly in all experiments. Arterial pressures were generally, but not always, lower during the period of the sustained elevation of left auricular pressure than during the control period. (3) Two of the 12 cats developed generalized pulmonary edema. These 2 had sustained left auricle pressures of 24 and 40 cm of water. (4) Although the above experiments do not preclude the possibility that other mechanisms may also be operating, they do suggest that left ventricular failure plays a role in the development of ammonium pulmonary edema in the cat.

The Measurement of Systemic Blood Flow.

Summary A technic of measuring total aortic flow has been presented which essentially reestablishes cardiovascular continuity, limits vascular dead space to less than 100 cc, and is accomplished by connections with intrathoracic arteries. The use of the Potter electro-turbinometer has eliminated the pressure buffer bottle, since it follows pulsatile flow accurately.

Effect of Aramine on the Survival of Dogs Subjected to Hemorrhagic Hypotension

One group of 19 control dogs and other group of 20 “treated” dogs were bled into hemorrhagic hypotension after Nembutal anesthesia and their arterial pressures controlled at 40 mm. Hg for an average period of one hour and fifteen minutes. Neither group had further blood depletion, or replacement, for an additional 1 hour and 39 minutes, but the treated group received Aramine. Reinfusion was performed after an oligemic period totaling 2 hours and 54 minutes. Of the dogs in the control group, 10.5 per cent survived; 50 per cent of the treated dogs survived.