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Flashcards in Congenital heart diseases Deck (47)
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31

Tetralogy of Fallot

Abnormalities found on special exams

  • Lab--erythrocytosis, inc. PCV 60-70%
  • Rads--R heart enlargement, small pulmonary vessels
  • Echo
    • Overriding aorta and VSD
    • Hypertrophy of R ventricle
  • Doppler--inc. peak flow across pulmonary valve, shunting through VSD
  • Angio--ID's the VSD, R ventricular hypertrophy, pulmonic stenosis, and direction of the shunt
  • Catheterization--measurement of the pressure gradient across the VSD
  • ECG--possible R ventricular enlargement

32

Tetralogy of Fallot

DDx

Prevention

  • DDx = other causes of cyanosis
  • Prevention = do not breed animals w/ this defect

33

Tetralogy of Fallot

Treatment

Prognosis

  • Surgical procedures to re-route blood--variable success
    • Subclavian attached to pulmonary artery to increase oxygenation or connect aorta to pulmonary artery--like PDA
  • Beta blockers--possibly lessen MVO2 of R ventricle or imrove distensibility
  • Hydroxurea--anti-cancer drug, blocks RBC production
  • Phlebotomies and replace blood with sterile saline; low dose aspirin to prevent thromboembolism
  • Vasodilators are contraindicated--will make R-L shunting worse and increase hypoxia
  • Prognosis--depends on the severity; some dogs live a long (though inactive) life

34

Atrial septal defect

Pathophysiology

  • "Common atrium"
  • Blood flows to right atrium because of its thinner, distensible walls
  • R ventricular enlargement due to volume overload
  • Enlarged pulmonary vessels
  • L-R shunt

35

Atrial septal defect

Signalment

Probable owner complaint/history

  • Signalment--found in younger animals during pediatric vaccinations
  • Complaint/history
    • Small defects present asymptomatically
    • Larger defects may present with heart failure signs

36

Atrial septal defect

Common abnormalities seen on PE

Abnormalities found on special exam

DDx

  • PE
    • Possible murmur heard over L heart base
    • May hear splitting of S2
  • Rads--R heart enlargement, prominent pulmonary vessels
  • DDx--pulmonic or aortic stenosis

37

Atrial septal defect

Treatment

Prognosis

Prevention

  • Treatment
    • Dependent on size of the defect--most with small defects will remain asymtomatic
    • Surgical correction of large defects will require bypass
  • Prognosis--depends on size; worse if tricuspid stenosis is also involved
  • Prevention--don't breed

38

Atrioventricular valve malformations

Pathophysiology

  • Thickened or fused valves
  • Papillary muscles that are malpositioned, partially developed, or absent
  • Chordae tendinae that are too long, too short, or absent
  • Valvular insufficiency most commonly seen with dyslastic valves failing to meet during systole--> regurg and volume overload
  • Valvular stenosis (rare)--stenotic valves decrease ventricular filling during diastole --> inc. atrial pressure and CHF

39

Atrioventricular valve malformations

Signalment

Probable owner complaint/history

  • Signalment
    • Most common congenital malformation in cats
    • Large breed dogs may be predisposed
  • History
    • Signs depend on the valve involved--L or R CHF signs

40

Atrioventricular valve malformations

Common abnormalities seen on PE

Abnormalities seen on special exam

Valve insufficiency--depend on valve affected

41

Atrioventricular valve malformations

DDx

Prevention

  • DDx
    • Other causes of diastolic murmurs--PDA, possible aortic stenosis
  • Prevention--don't breed

42

Atrioventricular valve malformations

Treatment

Prognosis

  • Treatment
    • Furosemide and an ACE inhibitor
    • Arterial vasodilators may be helpful by reducing regurg and promoting forward flow
    • Low sodium diet may be helpful
  • Prognosis
    • Depends on severity of defects

43

Endocardial fibroelastosis

All the things

 

  • Seen more in Burmese and Siamese kittens
  • Fibrosis of ventricular endocardium--> stiffening of walls--> decrease ability to dilate and fill during diastole
  • Left CHF by the time the animal is 2-4mo
  • No treatment

44

Persistent right aortic arch (PRAA)

Pathophysiology

Signlament

  • Vascular ring formed by the ligamentum arteriosus dorsally, aorta to the right, pulmonary artery to the left, and cardiac base ventrally--constricts esophagus and trachea
  • Signalment: common occurrence in GSDs

45

PRAA

Signs

Abnormalities on special exam

  • Signs
    • Megaesophagus cranial to the constriction = regurg of solid food
    • Asymptomatic at young age (liquid diet)
  • Rads: esophageal dilation cranial to the heart base

46

PRAA

Treatment

Prognosis

DDx

  • Treatment--surgical ligation and transection of LA
  • Guarded prognosis--esophageal fx may remain abnormal
    • Animals at risk for aspiration pneumonia
  • DDx: congenital megaesophagus

47

Inherited ventricular arrhythmias in GSDs

All the things

  • Possible genetic link in some lines of GSDs, otherwise idiopathic
  • Starting at 3 months, animals may be affected w/ mild VPDs or eisodes of VT and poss. sudden death
  • Severity will inc. until 7mo and then decreases
    • By 18mo risk of sudden death is markedly dec.
  • Severely affected animals can be given sotalol and mexiletine to dec. episodes of VT (does not prevent sudden death)
    • Sotalol alone is roarrhythmogenic and mexiletine alone has no affect
    • Drug trtmt until animals are 18 mo to 2 yrs