[Anonymous]

The echo is important to rule out a leaky valve, found a decent article on mitral valve insufficiency. Excerpt below: Can’t post the link but you can find the complete article at:
Doctors Foster and Smith Pet Education, Search articles for: Heart Failure (Mitral Valve Insufficiency) in the Dog

Treatment of dogs with mitral insufficiency depends upon the size of the heart and if clinical signs are present. Guidelines for the diagnosis and treatment of valvular heart disease in dogs are based on classifying dogs into several stages:
•Stage A: Dogs with no murmur or symptoms but who are at risk of developing valvular heart disease. These include Cavalier King Charles spaniels and small breeds of dogs.
•Stage B1: Dogs with no heart enlargement or symptoms.
•Stage B2: Dogs with enlarged left atriums and/or ventricles but no symptoms.
•Stage C: Dogs with heart enlargement and symptoms of congestive heart failure.
•Stage D: Dogs not responding to treatment for congestive heart failure.

Dogs in Stages A and B1 generally do not receive treatment, but are monitored for any changes in heart size or progression into symptoms.

Treatment of dogs in Stage B2 is controversial. Some veterinarians believe treatment of these dogs will slow progression of the disease, others do not.

Treatment of dogs in the Stage C with heart enlargement and symptoms is based on medications to help the heart pump more efficiently. Drugs that may be used include diuretics that cause the dog to urinate more and thereby remove excess fluids from his lungs. These include furosemide (Lasix) or spironolactone .
Medications such as pimobendan or an angiotensin-converting-enzyme (ACE) inhibitor like enalapril may be given to help the heart pump more efficiently. Digoxin, another heart medication may also be prescribed. If the dog does not respond well to these medications and is in Stage D, other therapies such as amlodipine may be used. Cough suppressants and bronchodilators may be prescribed is there is a chronic cough.

Diets lower in sodium may assist in decreasing the fluid build-up. It is important to maintain adequate protein intake. Attempts should be made to maintain the dog at his ideal weight. The use of omega-3 fatty acid supplements is often recommended.

What is prognosis for dogs with mitral valve insufficiency?

Many dogs with heart murmurs due to mitral valve insufficiency may live for years before developing any symptoms. They should be carefully monitored however, so treatment can be started as soon as warranted. In those dogs with heart failure, approximately half will not survive for more than 6-12 months.