Google "Small Vessel Disease". I have this and it is due to arteriosclerosis. It can effect any organ in the body. The small arteries and capillaries of the brain are often affected. Mine shows up on an MRI. The report says "changes noted due to SVD (Small Vessel Disease). I have had 2 strokes and have had many TIAs (transient ischemic attacks) sometimes called mini-strokes that do no damage. One stroke was light. One stroke was heavy.
Do you smoke? If you do, stop it.
You may be referring to a congenital condition that only effects the heart. If so, forget SVD....
In the heart it is classed as either microvascular angina or cmvd or small vessel disease. Im undergoing tests for it.