An<unk>  is a one-way valve implanted into a person's heart to replace a heart valve that is not functioning properly (valvular heart disease).<unk> s can be separated into three broad classes: mechanical heart valves, bioprosthetic tissue valves and engineered tissue valves. The human heart contains four valves: tricuspid valve, pulmonary valve, mitral valve and aortic valve. Their main purpose is to keep blood flowing in the proper direction through the heart, and from the heart into the major blood vessels connected to it (the pulmonary artery and the aorta). Heart valves can malfunction for a variety of reasons, which can impede the flow of blood through the valve (stenosis) and/or let blood flow backwards through the valve (regurgitation). Both processes put strain on the heart and may lead to serious problems, including heart failure. While some dysfunctional valves can be treated with drugs or repaired, others need to be replaced with an artificial valve.
Artificial heart valve
Bioartificial heart
Artificial cardiac pacemaker
Heart valve repair
Adjustable pressure-limiting valve
Cardiac pacemaker
Articulatory technique
Tissue engineering of heart valves