Valvular heart disease is what the name implies, it is the when the valves of the heart are diseased. They can be stenosed, or regurgitant. These terms, the causes and the consequences will be listen below.
Often auscultation of the heart valves is the diagnostic tool to listen for the murmurs heard in the different valvular pathologies
Stenosis
Stenosis is where the heart valves get worse at letting blood flow through. This can be because of fusion of commissures (the edges of the leaflets), and/or calcification and hardness of the valves.
An example of this is calcified aortic stenosis, which occurs due to a lot of the same factors as atherosclerosis but different pathogenesis. There is producetion of bone matrix proteins in the valves which become calcified and result in stenosis and some regurgitation
This can cause pressure overload in the (left) ventricle and subsequent hypertrophy (which can lead to eventual failure and dilation. This increased pressure can predispose to regurgitation by the mitral valve.
Regurgitation
This is when the valves get worse at letting blood back through in the backflow.
Causes
There are a few causes that lead to valvular pathologies, Some big ones are congential defect, like bicuspid aortic valve, which can lead to early failure, age, like we see in calcified aortic stenosis, or infectious origin, like we see in rheumatic heart disease and infectious endocarditis.
Sounds
To figure out where the valvular lesion is you can listen to the areas of the heart for each valve and listen where it is loudest, as well as comparing against pulse finishthis