Introduction
There are two cardiac valves on the left side (aortic and mitral) and two on the right side (pulmonary and tricuspid). The four valves control the direction of blood flow through the heart. The valves open and close passively in response to changes in volume and pressure within the chambers. Closure of the tricuspid and mitral valves is helped by the papillary muscles which are attached to the cusps of the atrioventricular (AV) valves by the chordae tendinae. Abnormalities of the papillary muscles or chordae tendinae can lead to valve incompetence. Valve dysfunction disrupts normal forward blood flow and places a haemodynamic burden on one or both ventricles. Picking up a murmur during auscultation of the heart is commonly the first step in diagnosing valvular heart disease.
Valvular stenosis and valvular incompetence
Valvular stenosis (restricted opening) causes pressure overloading and valvular incompetence (failure of closure) causes volume overloading. The symptoms and signs of valvular heart disease can be understood by considering the effects of pressure and/or volume overloading on the heart and cardiovascular system as a whole.
Types of valvular dysfunction
There are two main forms of aortic valve disease:
- Aortic stenosis (AS)
- Aortic regurgitation – aortic incompetence (AR)
There are three types of mitral valve dysfunction:
- Mitral stenosis (MS)
- Mitral regurgitation (MR)
- Mitral valve prolapse (MVP)
We will look at each of these in turn.