Heart valve defects including aortic stenosis and mitral valve conditions
Every mammalian heart has four chambers, and each has a valve that functions to prevent blood from passing in the opposite direction to normal flow. Heart valve defects are an important cause of heart failure and symptoms of breathlessness. They can mostly be detected by auscultation of the heart with a stethoscope.
All all four valves can be affected by conditions, the common conditions in humans are of the mitral and aortic valve. The aortic valve is the heart’s main non-return valve that blood passes through as it leaves the heart. This valve has a propensity to narrow with age, particularly in the 1 to 2% of the population born with two instead of the normal three cusps (so-called bicuspid valve).
The aortic valve can also leak, either due to defects of its leaflets or, in most cases, due to dilatation of the ring that it sits in, common enough in diseases that cause dilation or enlargement of the aorta, some of which, like high blood pressure, are quite common.
The mitral valve, separating the left atrium and the left ventricle, is the other valve that is also most commonly defective. Now that rheumatic fever in the UK is rare and mitral stenosis caused by rheumatic involvement is therefore also rare, the main condition causing mitral valve problems in adults is mitral regurgitation or leakiness, in many cases due to either dilatation of the mitral valve ring that it sits in within the heart, or rupture of one or more chordae tendineae (‘heart strings’), which, like parachute cords, support the mitral leaflet tips which prevent prolapse of the leaflets during each heartbeat.
All valve defects should be assessed with a combination of a bedside examination by a skilled practitioner, an echocardiogram, BNP blood test, and a 12-lead ECG. More sophisticated tests are needed in some patients who are being considered for mitral valve or aortic valve repair. Other techniques that are used include aortic valve surgery, TAVI, and minimally invasive mitral valve repair using MitraClip and Tendyne.