Great interview, but I am open to the mystery of the heart. If I look at it thru engineering eyes, if it were nearly a pump the structure of the vessels would have to be completely different for the blood to reach everywhere it needs to go and the force would have to be substantially greater to have the blood travel thru the kms of arteries and capillaries. No doubt it helps the flow,  but I believe that it’s the turbulising the addition of spiraling of the blood that could be one of the main functions of the heart. If I analyse the valves of the heart, they in their action make the blood spiral. Just like a flowing river with many rocks making much movement, the water is cleaner, more oxygenated and somehow more alive. Steiner wrote an article titled The Heart is not a pump. Worth keeping an open mind to in my opinion.