Aortic insufficiency (AI), also known as aortic regurgitation (AR), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle.
Definition of echidna. : a spiny-coated toothless burrowing nocturnal monotreme mammal (Tachyglossus aculeatus) of Australia, Tasmania, and New Guinea that has a long extensible tongue and long heavy claws and that feeds chiefly on ants; also : a related mammal (Zaglossus bruijni) of New Guinea having a longer snout and shorter spines.
What is henna? Henna is a small flowering shrub that has many uses. The fragrant flowers are used to create perfume, and the leaves are dried and then turned into a fine powder that's used for dying clothes, hair and temporarily dying the skin -- hence henna tattooing. The plant has even been known to treat skin conditions.