A substitute valve used to replace a diseased valve. There are two main types of prostheses: those made from biological tissues (e.g., the heart valves of animals, esp. pigs) and those made from biocompatible materials (e.g., metals or polymers). Biocompatible mechanical valves may be constructed in a variety of ways, e.g., from a ball that moves up and down in a cage; with bileaflet valves that close in the midline; or with a single leaflet (which tilts to open and close).
Valves responsible for controlling the flow of blood into and out of the chambers of the heart.
A heart chamber has a structure at its exit, comprising two or three cup-shaped flaps. This structure permits blood to flow out of the chamber while preventing it from flowing back. There are four heart valves in total: aortic, pulmonary, mitral, and tricuspid. Throughout each heart cycle, these valves open and close, creating the characteristic sounds of the heart.
Heart valves can suffer from two main issues: stenosis, which involves narrowing and forces the heart to work harder to pump blood through the valve, and incompetence or insufficiency, which results in leakiness and an inability of the valve to prevent blood from flowing backward (regurgitation). These defects can lead to the occurrence of heart murmurs.
Heart valve defects can either be present from birth (known as congenital heart disease) or acquired later in life. The most common congenital valve defects include aortic stenosis and pulmonary stenosis. On the other hand, acquired heart valve diseases usually result from degenerative changes or reduced blood supply (ischemia) affecting certain parts of the heart, leading to conditions like aortic stenosis or mitral incompetence. Mitral stenosis, mitral incompetence, defects of the aortic valve, tricuspid stenosis, and tricuspid incompetence can be caused by rheumatic fever. Additionally, bacterial endocarditis can also damage heart valves.
Heart valve disorders often result in heart failure, arrhythmias, or symptoms caused by insufficient blood supply to the tissues.
Heart valve defects can be detected through methods such as auscultation, chest X-ray, ECG (electrocardiogram), or echocardiography. Once diagnosed, these defects can often be corrected through heart valve surgery.