The Problem and Its Proposed Solution

The problematic situation in cardiovascular physiology was expressed by Berne and Levy 3
who wrote: "The problem of treating pulsatile flow through the cardiovascular system in
precise mathematical terms is virtually insuperable." A fundamental aspect of this problem
relates to the fact that the major portion of our knowledge of cardiac dynamics has been
deduced from pressure curves. In fact our knowledge of the system has two independent
sources: experimentally determined facts and logically deduced concepts from the pressure
propulsion premise. The situation is so confusing that some life scientists are considering
chaos theory and mathematics to try to find the order in the system. It will be shown that
the chaos derives from a mix of facts and conjectures and not from the nature of the
phenomenon itself.

It is our purpose to demonstrate that Borelli's premise is incorrect and to propose the
concept that the blood is propelled by a unique form of momentum. First, the aortic arch
does not respond as expected if the blood in it were under pressure. The aorta is a curved
tube; as such it has the basic form of the widely used pressure sensitive element of the
Bourdon tube gage*.

When the curved tube of the Bourdon gage is subject to positive pressure, it is forced to
straighten out as one sees in a garden hose. When subject to a negative pressure, the tube's
curvature is increased. During the systolic ejection (period when blood is ejected from
ventricle), the aorta's curvature is seen to increase, signifying that the aorta is not
undergoing a positive pressure, but rather is undergoing a negative pressure 4.
We demonstrate that this negative pressure is that associated with the vacuum center of
traveling vortices of blood. Thus the motion of the aorta, when considered as nature's
own pressure sensor, contradicts the pressure propulsion premise. Of course, the swirling
streams of the vortex have potential pressure, so any attempt to measure pressure will
result in a positive pressure reading due to interrupted momenta.

Movement without applied pressure is movement with momentum, as we observe so
dramatically in the long leaps of racing cats. It is also manifest in nature in flowing water in
open streams, traveling tornadoes, and jet streams which are actually horizontal spirals of
air and moisture that can be thousands of miles long and move around like meandering
rivers in the upper atmosphere. A thrown ball in its trajectory also moves without pressure.
What about the measured blood pressure? The concept under consideration here is the
well known ratio of force to area:

Pressure = force/area (force per unit area)

The pressure is an arithmetical ratio derived from the average force of the moving
blood, and as such, indicates the phenomenon of the moving blood indirectly. In a
momentum system the pressure is a potential while the object is in motion and becomes
manifest when the velocity is impeded:

Momentum (mass x velocity) = impulse (force x time)

The blood moves with various velocities in its vortex streams. At the moment of impact of
an object moving with momentum, the velocity decreases while the pressure of a certain
magnitude appears.

Rudolf Steiner, scientist and philosopher, pointed out on several occasions that the blood
moves autonomously 5, and that the pressure is not the cause of blood flow but the result
of it 6. The clinicians of old used elaborate methods of describing the nature of the arterial
pulse and the ictus cordis or the apex beat, which is the impulse of the heart against the
chest wall. Many descriptive terms such as thready pulse of hypovolemic shock, collapsing
or water-hammer pulse of aortic incompetence and `heaving' apical impulse of left
ventricular hypertrophy, convey the intuitive understanding of the real mechanism of the
heart's action.

An attempt to characterize left ventricular function by indices such as the maximal velocity
of contraction (Vmax) and the maximum change of left ventricular pressure with time
(dP/dtmax) suggests the felt inadequacy of the simple pressure propulsion concept.