Ahmed Valve: From 1 Different Sources
a *shunt used in the treatment of *glaucoma to reduce and control intraocular pressure. The device works by bypassing the *trabecular meshwork and redirecting the outflow of aqueous humour through a small tube into an outlet chamber.
The mitral valve, so-called because of its resemblance to a bishop’s mitre, is the valve which guards the opening between the ATRIUM and VENTRICLE on the left side of the HEART.... mitral valve
The valve, with three cusps or ?aps, that guards the opening from the right atrium into the right ventricle of the HEART.... tricuspid valve
The valve that controls the ?ow of blood from the AORTA to the left ventricle of the HEART.... aortic valve
A structure that allows fluid or semi-fluid material to flow in 1 direction through a tube or passageway but closes to prevent reflux in the opposite direction. The valves at the exits from the heart chambers and in the veins are essential to the circulatory system. There are also small valves in the vessels of the lymphatic system.... valve
These cup-like structures are found in the HEART, VEINS, and lymphatic vessels (see LYMPH); they ensure that the circulation of the blood and lymph goes always in one direction.... valves
See mitral valve prolapse.... floppy valve syndrome
An operation to correct a heart valve defect or to remove a diseased or damaged valve. A heart valve may have to be repaired, widened, or replaced because it is either incompetent (leaky) or stenotic (narrowed). Widening of a valve may involve valvotomy or valvuloplasty. A damaged valve can be replaced by a mechanical one (fashioned from metal and plastic), a valve constructed from human tissue, a pig valve, or a valve taken from a human donor after death. A heart–lung machine is used during replacement.After heart-valve surgery, symptoms such as breathlessness may take weeks to improve and require medication to be continued. Some people need longterm treatment with anticoagulant drugs to prevent the formation of blood clots around the new valve.... heart-valve surgery
A common, slight deformity of the mitral valve, in the left side of the heart, that can produce a degree of mitral incompetence. The prolapse is most common in women and causes a heart murmur. It may be inherited, but the cause is often unknown.Usually, there are no symptoms, and treatment is not needed. Occasionally, the condition may produce chest pain, arrhythmia, or, rarely, heart failure. Often, no treatment is required for mitral valve prolapse, but some people may be treated with beta-blocker drugs, diuretic drugs, antiarrhythmic drugs, or, rarely, heart-valve surgery.... mitral valve prolapse
A surgical operation to replace a defective or diseased heart valve. (See also heart-valve surgery.)... valve replacement
a form of mechanical prosthesis commonly used in the past for replacing damaged heart valves. Currently, most mechanical valve replacements are of the tilting-disc variety.... ball-and-cage valve
see mitral valve.... bicuspid valve
a valve at the junction of the small and large intestines consisting of two membranous folds that close to prevent the backflow of food from the colon and caecum to the ileum.... ileocaecal valve
a valve in the heart lying between the right ventricle and the pulmonary artery. It is a *semilunar valve that prevents blood returning to the ventricle from the pulmonary artery.... pulmonary valve
either of the two valves in the heart situated at the origin of the aorta (see aortic valve) and the pulmonary artery (see pulmonary valve). Each consists of three flaps (cusps), which maintain the flow of blood in one direction.... semilunar valve
a one-way valve used to drain cerebrospinal fluid in order to control *hydrocephalus. The device is inserted into the ventricles of the brain and passes via a subcutaneous tunnel to drain into either the right atrium or the peritoneum.... spitz–holter valve
the most commonly used form of mechanical heart valve replacement.... tilting-disc valve
(TAVI) replacement of the aortic valve in patients with *aortic stenosis using a catheter-delivered prosthesis rather than open heart surgery. Usually the catheter is passed via the femoral artery, but sometimes it can be passed via the subclavian artery or through the wall of the left ventricle via a localized *thoracotomy.... transcatheter aortic valve implantation
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