The heart’s job is to pump blood to and from all tissues. It pumps blood returning from the body through the right side of the heart to the lungs, where it collects oxygen. Then the left side pumps the blood back out into the body. However, when valves are not working, this process becomes less efficient, causing the heart to work harder.
The heart has two sides the right (red) and the left (blue). Each side is divided into two chambers: an atrium on the top and a ventricle on the bottom.
Between the atrium and ventricle on each side is a valve, the tricuspid on the left and the mitral on the right. These two valves regulate blood flow by opening and closing as the heart pumps, maintaining the blood flow in one direction.
For reasons we don’t completely understand, the mitral or tricuspid valves can become abnormally thickened and develop nodules. These changes mean the valves cannot form a tight seals between the atrium and ventricle, and begin to leak. This is called degenerative valve disease (DVD).
If the valve does not work properly, blood flow can leak back in the wrong direction. This is called valve regurgitation.
What Animals Are Affected by DVD (Degenerative Valve Disease)?
DVD is the cause of 75% of cardiovascular disease in dogs, and in 60% of the cases the mitral valve is degenerated. Small breed dogs have the highest incidence of DVD. The disease is uncommon in cats.The outcome of DVD in dogs really depends on the severity, and how early it is treated.
The regurgitation caused by DVD results in a murmur that your veterinarian can detect when listening to the heart.
- When the mitral valve fails, blood backs up into the atrium.
- This causes the left atrium and ventricle to become stretched or dilated.
- As blood backs up to the atrium, the heart eventually fails to pump blood forward.
- This causes the fluid to collect in the lungs.
- With nowhere else for the excess fluid to go, it builds up in the lungs.
- This results in congestive heart failure due to DVD of the mitral valve.
- Symptoms include: cough, shortness of breath, tiredness, lack of appetite and weight loss.
- When the tricuspid valve fails this builds up excess volume on the right side of the heart.
- This enlarges the right side of the heart.
- The excess volume backs up into the body causing fluid in the belly and limbs.
- Dogs with right sided congestive heart failure tend to develop enlarged abdomens with a “fluid wave”. They may seem uncomfortable, especially when laying down, and may have shortness of breath when sleeping or resting.
How is DVD treated?
Degenerative valve disease is generally treated with oral medications which reduce the excess fluid retention by the kidneys, relax blood vessels to control high blood pressure, and make it easier for the heart to pump blood. It is important to monitor your pet’s overall attitude at home. Keep a log of your pets respiratory rate at rest. This should be around 20-30 breaths per minute. Monitor for:
- Heavy or labored breathing
- Increased coughing
- Fainting spells
- Lack of appetite