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  • Geriatric small/toy breeds of dogs
  • May occur in other breeds of dogs, including larger breeds (especially the German Shepherd)
  • May be inherited in the Cavalier King Charles Spaniel and the Dachshund
  • Occurs in males > females, and males may be affected earlier than females


  • Usually free of clinical signs
    • Most dogs with CMVI never experience clinical signs related to this disorder. This occurs because the disease is very slowly progressive and it occurs in geriatric dogs at risk for other geriatric disorders that become life limiting prior to the onset of clinical signs of heart disease.
    • Presence of a mitral regurgitation (MR) murmur for months to years prior to onset of clinical signs
    • Coughing
      • May have been present for months
      • Productive or non-productive cough
    • Often no obvious exercise intolerance until in congestive heart failure
    • If heart failure is present, signs typical of congestive heart failure may occur (dyspnea, tachypnea, orthopnea, wheezing, coughing, weakness, exercise intolerance, etc)
    • Syncope may occur in some dogs,
      • May be associated with exertion, excitement, coughing, micturition, defecation
      • Secondary to pulmonary artery hypertension, arrhythmias, or vasovagal syncope
    • Ascites may be present.

Physical Examination:

  • Systolic heart murmur of MR (PMI over left apex)
    • If MR is moderate to severe, the murmur tends to continue into and through the second heart sound, obscuring the second heart sound (pansystolic murmur)
    • The severity of MR is related to the intensity of the systolic murmur (grade of murmur).
  • A mid-systolic click may be heard in early CMVI
  • Arrhythmias are uncommon in the early stage of the disease and may be present late in the disease
  • Femoral pulses are often normal
  • Cough may be easily elicited on tracheal palpation. This is not an indication of advanced CMVI but is usually related to co-existing tracheal disease particularly tracheal collapse
  • Fine crackles, snaps, or popping sounds at end inspiration and early expiration may be heard if pulmonary edema is present. However these sounds may also represent small airway disease.
  • If heart failure is present, other signs may be observed (see Clinical Evaluation of Heart Disease section

Comment: When pulmonary hypertension develops, dogs become severely exercise intolerant and syncope is common.