Endocardial fibroelastose

Question 1

Which breeds are reported to develop this condition?

Answer 1

o Dogs: Labs, Great Dane, English Bulldogs, Boxer, Springer Spaniel
o Cats: Burmese, Siamese

Question 2

Epidemio

Answer 2

• Rare cause of myocardial failure in young dogs/cats <6mo
• Unknown mode of inheritance

Question 3

Clinical presentation

Answer 3

• C/s and PE: tachycardia, gallop rhythm, systolic murmur, cardiomegaly, CHF
  o Early development of L or biventricular failure <6mo
• Onset often precipitated by respiratory infection btw 3w-4mo
• Short course
• Sudden death not uncommon

Question 4

Gross lesions

Answer 4

• Diffuse fibrous and elastic endocardial thickening
  o Usually involve L side: LA, LV, MV
• LAE, LVE
• Thickened endocardium: 3-5x normal thickness
• Diffuse, white, opaque endocardial surface
• Dilated lymphatics commons

Question 5

other causes of endocardial thickening

Answer 5

o Other congenital malformations: hypoplastic LV)
o Viral myocarditis
o Cardiomyopathy
o Myocardiosis
o Myocardial necrosis

Question 6

Pathophys

Answer 6

• Diffuse myocardial failure → lesions not confined to endocardium
  o ALTERED LYMPHATIC DRAINAGE
  o If only endocardium would provoke diastolic dysfct from ventricular restriction

Question 7

Histo lesions

Answer 7

• Diffuse, hypocellular, fibroelastic thickening
  of endocardium
  o Purkinje cells: trapped into fibroelastic proliferation → atrophy in later stages
• Layering of thin, randomly organized collagen and elastic fibers
• Thick, more organized fibers adjacent to normal myocardium
• Endocardial edema and dilated lymph vessels
• No endocardial inflammation, fibrosis

Question 8

Sequence of dz

Answer 8

• <2-5days: no lesions
• Day 5-19: endocardial edema + fibroblast proliferation
• Day 19: LVE + endocardial thickening