Diseases of the cardiovascular system II

Question 1

What is a congenital heart disease?

Answer 1

Any functional or anatomical abnormality that is present at birth- caused by either genetic or non-genetic factors

Question 2

What additional signs can develop with severe defects of congenital heart disease?

Answer 2

• failure to grow at a normal rate or to a normal size
• exertional fatigue
• abdominal distension
• Episodic weakness
• Cyanosis

Question 3

At what age does congenital heart disease usually disappear

Answer 3

Normally disappears when the animal is 15-16 weeks

Question 4

Name 4 less common congenital conditions

Answer 4

1. Right-sided aortic arch
2. Atrial septal defect
3. Reversed, R-L shunting, patent ductus arteriosus
4. Aortic-Pulmonary window

Question 5

What does the ductus arteriosus connect?

Answer 5

Connects the main pulmonary artery to the aorta in the fetus

Question 6

Why might the patent ductus arteriosis fail to close in dogs?

Answer 6

Due to a lack of smooth muscle

Question 7

What is the pathophysiology of the patent ductus arteriosus?

Answer 7

• Flow through PDA
• pulmonary overcirculation
• Increase in pulmonary venous return and therefore left end-diastolic volume
• Increased LV stroke volume
• LV remodels with eccentric hypertrophy
• Increased systolic aortic pressure

Question 8

What are the clinical signs of patent ductus arteriosus

Answer 8

• High-Grade Continuous ‘machinery’ murmur
• Hyperkinetic ‘water hammer’ pulses caused by increased aortic systolic pressure and decreased aortci diastolic pressure
• Precordial impulse felt over a larger area
• 2/3 present with congestive heart failure if not treated within a year

Question 9

How would you diagnose a patent ductus arteriosis?

Answer 9

Auscultation

Question 10

What is the best way to treat a (left to right) patent ductus arteriosus?

Answer 10

Ligation of the ductus via a thoracotomy or interventional catheterisation procedure
* immediate decrease in left sided volume overload, gradual reversal of eccentric hypertrophy over time + excellent prognosis

Question 11

What are the clinical signs of a reverse patent ductus arteriosus?

Answer 11

• Differential cyanosis

Question 12

Why is closure of the PDA contraindicated?

Answer 12

R-L shunt due to high pulmonary pressure so closure would increase pulmonary pressure even more

Question 13

What is pulmonary stenosis?

Answer 13

Varying degrees of obstruction to the right ventricular outflow tract, lesions are either valvular, subvalvular or supravalvular

Question 14

In what species is pulmonic stenosis uncommon?

Answer 14

It is uncommon in cats

Question 15

What breeds are predisposed to pulmonic stenosis?

Answer 15

• Boxers, Beagles, Bull Mastiffs, Bulldogs, Cocker Spaniels, Miniature schnauzers, terriors, chihuahuas

Question 16

What is the pathophysiology of pulmonic stenosis?

Answer 16

• Fibrous ring of tissue located in the RVOT
• Concentric hypertrophy is proportional to the stenosis severity

Question 17

What are the clinical findings of pulmonic stenosis?

Answer 17

• syncope -> CHF -> Sudden death -> all depends on the stenosis severity
• Murmur intensity all correlates with the severity of stenosis

Question 18

How might you treat pulmonic stenosis?

Answer 18

• Medical management includes beta-blockers
• Minimally invasive balloon valvuloplasty
• Various surgical treatments via thoracotomy

Question 19

What is the prognosis for pulmonic stenosis?

Answer 19

Depends on the severity and presence of CHF

Question 20

What is aortic stenosis?

Answer 20

Varying degrees of obstruction of the left ventricular outflow tract, lesions may be subvalvuar, valvular or supravalvular
(important disease in large-breed dogs)
very rare in cats

Question 21

What is the pathophysiology of subvalvular aortic stenosis?

Answer 21

Fibrous ring of tissue located in the LVOT
* Concentric hypertrophy is proportional to the severity of stenosis

Question 22

What are the clinical findings of subvalvular aortic stenosis?

Answer 22

• Asymptomatic
• Clinical heart failure
• Auscultation = systolic ejection type, harsh murmur is the loudest over the heart base, radiating up the carotid arteries in severe cases
• murmur intensity correlates with the stenosis severity

Question 23

What does an ECG from subvalvular aortic stenosis look like?

Answer 23

• Often normal
• Can indicate left ventricular enlargement

Question 24

What does the echocardiography of aortic stenosis look like?

Answer 24

• Concentric LV hypertrophy
• Subvalvular obstructive lesion
• Post stenotic dilation of the aorta
• High velocity of blood across the valve

Question 25

How might you treat a moderate/ severe subvalvular aortic stenosis?

Answer 25

• Atenolol- beta blocker, decreases myocardial oxygen consumption, slows the maximum HR, improves diastolic filling
• Balloon dilation- no evidence to suggest it imptoves survival over atenolol
• Surgery- again no evdience to suggest it improves survival

Question 26

What is the most common congenital cardiac abnormality in cats?

Answer 26

VSD

Question 27

What are the two types of ASD?

Answer 27

• Ostium primum
• Ostium secundum