What Is Valve Disease?

Mitral valve disease is the most common form of heart disease in the dog.1

As the name suggests, this disease affects one or more of the heart valves. Mitral valve disease causes the edges to become thickened, lumpy, and distorted. The seal is now imperfect and when the ventricle pumps, some of the blood flows backwards into the atrium. Heart valves normally form a perfect seal when closed. However, in valve disease one or more of these valves "leak," allowing blood to be pumped backwards. This backward flow creates a noise, called a murmur, which your veterinarian can hear with a stethoscope.

Listen to a normal heartbeat

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Now listen to a heart murmur

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For a time your dog’s body may make adjustments to allow it to cope. In fact, some dogs manage with a murmur for many years. However, at some point, the disease may override the adjustments that have been made and the dog can become unwell and show some signs of congestive heart failure.

Valvular disease is 1.5 times more common in male dogs than females.1 This form of heart disease usually occurs in small- to medium-size dogs, less than 20 kg.1,2 The most susceptible breeds are Cavalier King Charles Spaniels, Poodles, Schnauzers, Chihuahuas, and Fox Terriers.3

 

Almost all small breeds are at risk for disease of the heart valve:

  • Cavalier King Charles Spaniel
  • Boston Terrier
  • Chihuahua
  • Fox Terrier
  • Miniature Pinscher
  • Poodle
  • Pekingese
  • Pomeranian
  • Whippet


If your dog is one of these breeds, there is no need to be alarmed. But you should watch for early signs of heart failure.

1. Atkins C, Bonagura J, Ettinger S, et al. Guidelines for the diagnosis and treatment of canine chronic valvular heart disease. J Vet Intern Med 2009; 23(6):1142–1150. 2. Rush JE. Chronic valvular heart disease in dogs. Proceedings from: 26th Annual Waltham Diets/OSU Symposium for the treatment of small animal cardiology, October 19–20, 2002. 3. Ware WA. Cardiovascular Disease in Small Animal Medicine. London: Manson Publishing Ltd; 2011.

Facts about heart disease brochure

Facts about heart disease brochure

Learn more about canine heart disease…and help protect your dog’s heart.