The heart contains four valves:

1. mitral valve (left AV)- the valve between the left atrium and left ventricle
2. tricuspid valve (right AV)- the valve between the right atrium and right ventricle
3. aortic or left semilunar valve-the valve between the left ventricle and aortic valve
4. pulmonic or right semilunar valve-the valve between right ventricle and the pulmonary artery

Valve dysfunction occurs by either congenital or acquired heart disease. The clinical finding of valvular disease is a cardiac murmur.

Types of valvular disease:

Endocardosis- This is a degenerative disorder and occurs most frequently in dogs and usually involves the mitral valve. Congenital Aortic Stenosis- Congenital pulmonic valve stenosis Bacterial endocarditis Valvular disease due to cardiomyopathy

Diagnosis is made by clinical signs, auscultation (listening to the heart), xray, ultrasound as the definitive diagnostic tool.

Treatment is based on the type and severity of the valvular disease. Currently, treatment of asymptomatic dogs is not recommended unless changes of the heart size are observed on x-ray.

As the severity of the disease progresses, diuretics, low sodium diets, digoxin, and vasodilator therapy is begun. In most cases the vasodilator can be an ACE (angiotension-converting enzyme) inhibitor. Furosamide is usually the diuretic first administered. The use of digoxin in dogs with valvular disease is somewhat controversial. Most cardiologists now advocate its use in mild cases of heart failure. It is most definitely used if arrhythmias (abnormal heart beats) are present and if advanced heart failure is present.

There are many other vasodilators available for use such as hydralizine, prazosin, and diltiazem to name a few. Your veterinarian will prescribe the medication and regimen they are most familiar with.