Health & Testing
The MVD Cardiac Protocol: Why Cavaliers Require Heart Testing Beyond DNA
Mitral Valve Disease is the most serious health concern in Cavaliers — and unlike most conditions, it requires clinical evaluation, not just a DNA test. Here's what ethical Cavalier breeders do.
February 3, 2024 · 6 min read
What Is Mitral Valve Disease in Cavaliers?
Mitral Valve Disease (MVD) is a progressive deterioration of the heart's mitral valve — the valve between the left atrium and left ventricle. As the valve deteriorates, it leaks, causing a heart murmur and eventually congestive heart failure. In Cavalier King Charles Spaniels, MVD is shockingly prevalent: over 50% of Cavaliers develop a heart murmur by age 5, and nearly all Cavaliers develop one by age 10. It is the leading cause of death in the breed.
Why DNA Tests Can't Screen for MVD
MVD is not caused by a single identified genetic variant — it's a polygenic condition influenced by many genes, making a simple DNA test impossible with current technology. The only way to assess MVD status is cardiac auscultation by a board-certified cardiologist (ACVIM-certified internist or cardiologist), who listens for a murmur and grades its severity. This evaluation must be repeated before each breeding because MVD progresses with age.
The MVD Breeding Protocol
Developed by the Cavalier Health organization and endorsed by multiple veterinary cardiology groups, the MVD Protocol recommends:
- Both parents must be examined by a board-certified cardiologist and found to be free of murmur before breeding.
- Both parents must be at least 2.5 years old at the time of cardiac clearance for breeding.
- Both parents' parents (all four grandparents) must also have been free of cardiac murmur until at least age 5.
- Annual re-evaluation before each breeding season.
How This Applies to Cavapoos
For Cavapoo breeders, the Cavalier parent must have the same MVD clearance as a pure Cavalier breeding dog. A Cavapoo breeder who shows DNA results without a cardiac clearance from a cardiologist on the Cavalier parent is missing the single most important health test in the program. Ask specifically: 'When was the Cavalier parent last cardiac-cleared by a cardiologist?'