Diseases of the cardiovascular system II Flashcards
What is a congenital heart disease?
Any functional or anatomical abnormality that is present at birth- caused by either genetic or non-genetic factors
What additional signs can develop with severe defects of congenital heart disease?
- failure to grow at a normal rate or to a normal size
- exertional fatigue
- abdominal distension
- Episodic weakness
- Cyanosis
At what age does congenital heart disease usually disappear
Normally disappears when the animal is 15-16 weeks
Name 4 less common congenital conditions
- Right-sided aortic arch
- Atrial septal defect
- Reversed, R-L shunting, patent ductus arteriosus
- Aortic-Pulmonary window
What does the ductus arteriosus connect?
Connects the main pulmonary artery to the aorta in the fetus
Why might the patent ductus arteriosis fail to close in dogs?
Due to a lack of smooth muscle
What is the pathophysiology of the patent ductus arteriosus?
- 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
What are the clinical signs of patent ductus arteriosus
- 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
How would you diagnose a patent ductus arteriosis?
Auscultation
What is the best way to treat a (left to right) patent ductus arteriosus?
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
What are the clinical signs of a reverse patent ductus arteriosus?
- Differential cyanosis
Why is closure of the PDA contraindicated?
R-L shunt due to high pulmonary pressure so closure would increase pulmonary pressure even more
What is pulmonary stenosis?
Varying degrees of obstruction to the right ventricular outflow tract, lesions are either valvular, subvalvular or supravalvular
In what species is pulmonic stenosis uncommon?
It is uncommon in cats
What breeds are predisposed to pulmonic stenosis?
- Boxers, Beagles, Bull Mastiffs, Bulldogs, Cocker Spaniels, Miniature schnauzers, terriors, chihuahuas
What is the pathophysiology of pulmonic stenosis?
- Fibrous ring of tissue located in the RVOT
- Concentric hypertrophy is proportional to the stenosis severity
What are the clinical findings of pulmonic stenosis?
- syncope -> CHF -> Sudden death -> all depends on the stenosis severity
- Murmur intensity all correlates with the severity of stenosis
How might you treat pulmonic stenosis?
- Medical management includes beta-blockers
- Minimally invasive balloon valvuloplasty
- Various surgical treatments via thoracotomy
What is the prognosis for pulmonic stenosis?
Depends on the severity and presence of CHF
What is aortic stenosis?
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
What is the pathophysiology of subvalvular aortic stenosis?
Fibrous ring of tissue located in the LVOT
* Concentric hypertrophy is proportional to the severity of stenosis
What are the clinical findings of subvalvular aortic stenosis?
- 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
What does an ECG from subvalvular aortic stenosis look like?
- Often normal
- Can indicate left ventricular enlargement
What does the echocardiography of aortic stenosis look like?
- Concentric LV hypertrophy
- Subvalvular obstructive lesion
- Post stenotic dilation of the aorta
- High velocity of blood across the valve
How might you treat a moderate/ severe subvalvular aortic stenosis?
- 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
What is the most common congenital cardiac abnormality in cats?
VSD
What are the two types of ASD?
- Ostium primum
- Ostium secundum
