endocardial disease

• Endocardial (Valve) disease has two forms…

  • Acquired form
  • Chronic degenerative valvular disease (CDVD) is the most common of heart disease in practice
  • Endocarditis (rarely present with this but there may be more incidences of it)
  • Traumatic injury (v rare)
  • Congenital form –valve dysplasia's
  • Insufficient valve
  • Stenotic valve
• Endocardial (Valve) disease occurs via Myxomatous (nodular appearance) degeneration of the mitral and/or tricuspid valve. There is thickening and redundancy of heart valve leaflets (often the side closest to the septum) with prominent nodular thickenings. As the valve gets thicker it doesn’t shut adequately causing blood regurgitation from ventricles to the atrium. Stroke volume increases and forward output falls. Less blood is then ejected around the body due to regurgitation therefore less blood reaches the circulation.
• Regurgitation = end diastolic volume is bigger while end systolic diameter is smaller
• Signalment of these patients are middle to older age patients (tends to be 8 to 9 years old but disease can occur at a younger age) with smaller breeds being overrepresented
• If in congestive failure, they present with…

  • Exercise intolerance (the most common sign, not the coughing dog)
  • Increased respiratory rate and effort
  • Coughing (usually due to pulmonary oedema not due to cardiac enlargement and hence occurs later in the disease process)
  • Decreased appetite

  But may present for a booster and you find a heart murmur with no other clinical signs!

  • If mitral valve (most common) place of maximum intensity is the left apex
  • If tricuspid the place of maximum intensity is the right apex
• Signs of significant disease include the below and if they are present investigations are needed.

  • Grade 3 murmur or louder
  • If less than a grade 3, well in self, could leave for some time but will likely get worse so always offer investigation
  • Heart rate greater than 120 (put your patient into context)
  • Loss of sinus arrhythmia (cats don’t have a sinus arrhythmia)
  • Pre-cordial thrill
  • Dysrhythmia
  • Pulse deficits
  • Weight loss
  • Signs of congestive failure (fluid build-up in places)

  Treatment depends on the stage of the disease
• Myxomatous - gelatinous connective tissue remodelling causing transformation of mitral valve leaflets and sub valvular apparatus that causes their weakening and increased risk of secondary complications
• Chronic degenerative valve disease - a consequence of degeneration of the valves between the atrium and ventricle on both the right and left however one side may be more affected. This causes a thick and nodular appearance.

  • Can also be the semilunar valves (aortic and pulmonic)
• Endocarditis - a life threatening inflammation of the inner lining of the hearts chambers and valves (the endocardium)
• Arrhythmia - a problem with the rate or rhythm of a heart beat
• stage A heart disease = dogs at a high risk of heart disease but no disease is currently present
• stage B heart disease = a murmur is heard but there are no visible signs of heart failure

  • Stage B1 = the heart does not appear enlarged or changed on radiography
  • stage B2 = the heart does appear enlarged or changed on radiography
• stage C of heart disease = evidence of heart failure is visible and treatment is necessary
• stage D of heart disease = hard to manage heart failure which is not responding to standard treatment
• If medication is given at stage B2 then we can expand their lifespan
• Investigations include…

  • Echocardiography for disease diagnosis and staging
  • If you get a mosaic pattern on doppler then there is regurgitation
  • Thoracic radiography to assess for fluid, cardiac enlargement and staging
  • Electrocardiogram to assess rhythm
  • This looks for any arrhythmia, absence of sinus arrhythmia, tachycardia, changes in complex morphology
  • Biochemistry
  • Blood pressure to identify hypertension
• • Radiographic abnormalities of mitral regurgitation include left sided cardiomegaly…
  • Elevation of distal trachea
  • Increased cardiac silhouette height
  • Straightening of caudal border of the heart and loss of cardiac waist
  • “Tenting” of left atrium
  • Splitting of mainstem bronchi
  • Bulge on cardiac silhouette at 2-3 o’clock in DV = left atrial appendage