No-one seems to be clicking the link to read Cowans proposition. So here’s the basics (from the link)
The Problem With Viewing the Heart as a Pump
Cardiologists and doctors in general are taught that the walls of the heart create pressure, which causes propulsion of the blood through the body. In essence, the heart is viewed as a pump — a pressure propulsion system caused by the muscular contraction of the ventricles.
However, your body actually contains an enormous amount of blood vessels. Most of the blood vessels in your heart and body are capillaries, which are very thin-walled, very narrow tubes.
If you were to spread these blood vessels out, they would cover three football fields. If you were to place the blood vessels end to end, in a series, they would encircle the Earth between one and three times.
"The pump theory is you have a 1-pound, somewhat thin-walled organ, and it’s going to pump [blood] around the Earth every single day for 70 years; 60 to 70 times a minute. That 1-pound, thin-walled organ can [supposedly] generate enough pressure [to do that] by squeezing …
Frankly, that's ridiculous. But it actually gets worse than that. If you do a flow velocity diagram, it turns out that the blood is moving the fastest at the heart, both before and after the heart.
As it goes into the arterioles and then the smaller arteries, it gets to the capillaries … [where] it actually stops and does a little shimmy, or it goes very slow, depending on who you believe … The analogy is, a narrow river goes fast and when it goes out into a wetland, it goes very slow.
It has to go slow — it has to stop almost — to exchange the gasses and the food. So not only are we pushing all the way around the Earth, but halfway around our travel, we stop and then we get going again. You're expecting that to be all from the push from behind …
It even gets worse than that because we have an outflow tube of the left ventricle called the aortic arch … which is shaped like McDonald's arch. The blood goes from the left ventricle, out the aortic valve, through the arch, then down to the body.
The analogy here is if you stick a similarly shaped arched garden hose off your spigot outside your house, and then turn it on really hard, which recreates the pumping … you would expect the garden hose to straighten out because if you put pressure, the arch would straighten.
In fact, you can look on any angiogram and catheterization and you can see that arch actually bends in a little bit during systole, which from a pressure propulsion model makes absolutely no sense at all."
The Hydraulic Ram Model of the Heart
Clearly, if your heart stops beating, you won’t live very long, but if the heart isn’t actually pumping the blood, how does it work? In his book, Cowan describes the heart as a hydraulic ram, which he explains thus:
"What does the heart do? The blood is moving fast. It comes into the heart. The heart stops the blood, and like a hydraulic ram, it holds it back. The walls expand. The pressure differential happens, and then it opens the gate and comes out.
More so when the blood is in the heart, because of the unique shape of the heart … The heart is a vortex-creating machine … *t has these trabeculae (fibers) inside the heart. Each area of the trabeculae is connected with a certain part of the body.
[One] area of the heart is connected with the spleen, another area of the inner part of the heart is connected with the foot, and so on.
The blood comes in and these areas of the heart create their individual spirals, and package up certain parts of the blood, like the old red blood cells, into a vortex and send it to the spleen, whereas another part sends the fresh new red blood cells up to the brain.
If there's a cut on your leg, it dissolves some of the inner fibers, puts that in a vortex and sends that to the cut on your leg. It's so wild. Again, there's an article about this on my website, as hard as it is to believe, that actually documents that in very clear terminology how this happens."