Aortic regurgitation occurs when blood flows retrograde (backwards) across the aortic valve from the aorta into the left ventricle during diastole. This abnormal backflow of blood leads to ...

goes to the thick walled left ventricle, then to the single right aortic arch then on to body. Also 4 chambered heart, with full double circulation. Sinus venosus is incorporated into the wall of the ...