Studies on Starling's Law of the Heart. I. The Circulatory Response to Acute Hypervolemia and Its Modification by Ganglionic Blockade

Behavior of Normal Pulmonary Circulation during Changes of Total Blood Volume in Man*

“…Nevertheless, it is noteworthy that a passive distension of the pulmonary vasculature has been suggested to occur by Frye and Braunwald, who measured the "central" blood volume in patients receiving a transfusion of 1j L of blood during the action of a ganglionic blocking agent. The same patients had no significant change of the "central" blood volume when the same amount of blood was infused in the absence of ganglionic blockade (25).…”

“…Consequently, the pressure-volume (distensibility) and pressure-flow (vascular resistance) relationships here described may represent the integrated effect of many determinants. There are several reasons to believe that changes in total effective blood volume activate the autonomic nervous control of the circulation (25), mainly through direct action on the intracardiac and vascular stretch-receptors (26,27). As pointed out by Braunwald, Frahm, and Ross, a rise in total blood volume is usually accompanied by a reflex decrease in the tone of the systemic arteriolar and venous beds (28).…”

“…As a consequence of the decrease in tone, the capacity of the venous bed increases and the infused fluid tends to pool in this portion of the circulatory system. Any notable increment of the volume of blood in the heart and lungs would then be prevented (25,28). Accordingly, the pulmonary circulation would play a completely passive role in the distribution of circulating blood.…”

Autocorrelation Patterns in the Left-Ventricular Pressure Course of Isolated Working Hearts at Sinus Rhythm

“…The response curve is adjusted (shifted) by other regulatory pathways and attributed to Ca 2+ sensitivity of the myocardial filament which increases with precontraction sarcomere length (length dependent activation) [20,22,23,24]. As standing to reason, this effect has been thoroughly investigated by sudden preload changes [25,26] and in the presence of spontaneous [16] or artificially induced ventricular arrhythmia [27,28]. Physiological importance of Frank-Starling's law is acknowledged in attuning right and left cardiac output [21]; apart of that, it is considered somewhat to compensate for lacking neuro-humoral regulation (elderly [19]), transplant recipients [5]) or arrhythmia [16,28].…”

“…Physiological importance of Frank-Starling's law is acknowledged in attuning right and left cardiac output [21]; apart of that, it is considered somewhat to compensate for lacking neuro-humoral regulation (elderly [19]), transplant recipients [5]) or arrhythmia [16,28]. It has been stated that Starling's law cannot readily been demonstrated even by gross volume changes in healthy subjects, due to autonomic nervous counteraction [25]; subsequent studies relativised this notion [22,26].…”