Okay, I have two questions

The first is:Does blood flow to the heart muscle during contraction or relaxation?

The second is:What are problems associated with a hole in the heart?

Thanks:)

Someone who knows better will correct me if I'm wrong. Been a dozen years since I've had a bio or physio book open.

My understanding is that when the atria contract it is to push blood to the lower chambers of the heart, the ventricles. When the right ventricle contracts it pushes blood to the lungs and when the left ventricle contracts it pushes the oxygenated blood to the rest of the body.

Seems to me that blood would most easily enter the atria right after a contraction. If the heart is contracting it is forcing blood away and the valves of the heart are closed by back pressure. After the heart has pushed the blood out, the blood vessels, I believe, force the blood back into the heart by some elastic rebound of the walls and the blood moving toward lower pressure (toward the heart).

As for a hole in the heart, well again, others could fill you in better. This would allow for nonoxygenated blood to mix with oxygenated, and I imagine there are problems with blood pressure since the all the chambers do not constrict at once. Think about blowing liquid through a straw versus blowing liquid through a straw with a hole in it. Wouldn't get the same pressure.

That's all I know or can guess.