1. DISEASES OF THE CARDIOVASCULAR SYSTEM:
CONGENITAL DEFECTS

2. CONGENITAL DEFECTS: PATENT DUCTUS ARTERIOSUS
Mostly in small breed dogs. Show signs as puppies.
CHIHUAHUAS, MALTESE, POODLE, POMERANIAN, SHELTIE
PUPPIES COMMONLY AFFECTED

3. CONGENITAL DEFECTS: PATENT DUCTUS ARTERIOSUS
PDA: Open and ductus artesiosus: blood vessel ONLY present in the fetus. Should close off when puppy is born. RA to RV to Pulmonary a. to lungs than back to left. In foetus ungs don’t work. SO their blood is oxygenated by mother. The pulmonary a goes to the aorta via ductus artesiosus. Extra blood goes to the lungs, so extra blood going to LA – LV – Aorta, cycling of blood over time L side of heart more blood than R side. L sided heart failure.
Normally, the ductus arteriosus carries blood from the pulmonary artery
to the aorta during fetal development. It bypasses the lungs of the fetus.

4. CONGENITAL DEFECTS: PATENT DUCTUS ARTERIOSUS
The duct should close in the first hours after birth. If it does not, the blood begins to shunt from the aorta into the pulmonary artery and hyperperfuse the lungs.
The left side of the heart will have an increase in blood return and become volume overloaded.
Too much blood is going to the lungs. RA – RV – Lungs _ LA – LV – Aorta now blood shunts backwards because pressure in L side higher than R so pressure in aorta in higher it backflows (it is already oxygenated) and prevents the blood that needs to be oxyenate doesn’t get there. Dispalces blood that needs to be oxygenated. Mixed blood in oxygenation. L sided heart failure. L to R shunt.
THIS IS CALLED A LEFT-TO-RIGHT SHUNT

5. CONGENITAL DEFECTS: PATENT DUCTUS ARTERIOSUS (PDA)

6. CONGENITAL DEFECTS: PATENT DUCTUS ARTERIOSUS
CLINICAL SIGNS:
A loud murmur best heard over the left base
Sometimes called a “machinery” murmur or a continuous murmur
If the shunt is small some animals may be asymptomatic
In large shunts the animal will develop left-sided heart failure
Pulmonary edema
Cough
Exercise intolerance
Tachypnea
Weight loss
ECG: wide range of arrhythmias including APCs and VPCs
Echocardiography (ultrasound)
Radiographs: left atrial and ventricular enlargement
Diagnose: Heartmurmur that does not go away. We think of PDA. Between S1 and S2.

7. PATENT DUCTUS ARTERIOSUS: TREATMENT
EXCELLENT PROGNOSIS WITH SURGICAL CORRECTION: LIGATION OF
THE DUCTUS ARTERIOSUS

8. PATENT DUCTUS ARTERIOSUS: TREATMENT
CLIENT INFO:
64% OF ANIMALS WILL DIE WITHIN 1 YEAR IF NOT TREATED SURGICALLY
Dogs with this condition should not be used for breeding

9. CONGENITAL DEFECTS: ATRIAL AND VENTRICULAR SEPTAL DEFECTS
Atrial Septal Defect
Defect between RA to LA: Foramen ovale ok in fetus, to bypass the lungs. Same as PDA, backflow of blood. Blood shunt form L to R. Overload to R side, R side heart failure (PDA is L sided heart failure). Flap closes and seals the hole.
During fetal life, the foramen ovale is an openingi n the interatrial septum, allowing shunting of blood from the right atrium to the left atrium in order to bypass the nonfunctioning fetal lungs. It should close at birth. If it doesn’t, after birth, the blood will shunt from left to right resulting in overload of the right side of the heart.

10. CONGENITAL DEFECTS: ATRIAL AND VENTRICULAR SEPTAL DEFECTS
CLINICAL SIGNS: ATRIAL SEPTAL DEFECTS
Result in overload of the right side of the heart → dilation and hypertrophy of the right-sided chambers
Systolic murmur
Right-sided heart failure
Radiographs: right ventricular enlargement
Echo: right ventricular dilatation

11. CONGENITAL DEFECTS: ATRIAL AND VENTRICULAR SEPTAL DEFECTS
Hole between ventrices. Not normal in the foetus. Backflow to RV and lungs, and back to the L side. Left sided heart failure. Defect, high pressure shunts blood. L side feels grunt cause immediately to artery.
Blood is shunted from the oxygen-rich left ventricle into the right ventricle. The blood
goes through pulmonary circulation and right back into the left atrium and ventricle
resulting in volume overload of the left side of the heart. The right ventricle may dilate
as well.

12. CONGENITAL DEFECTS: ATRIAL AND VENTRICULAR SEPTAL DEFECTS
CLINICAL SIGNS: VENTRICULAR SEPTAL DEFECTS:
Animals with small defects may have minimal or no signs
Larger defects may result in acute left-sided heart failure, usually by 8 weeks of age
A harsh holosystolic murmur
CLIENT INFO:
Repair of these defects requires open-heart surgery or cardiopulmonary bypass. These procedures are uncommon in the dog and cat
Most of these animals will eventually experience development of congestive heart failure
Holosystolic murmur: All the time during systole.

13. CONGENITAL DEFECTS: PULMONIC STENOSIS
Valve is too narrow.
Chihuahuas, English Bulldogs, are commonly affected. CAUSE: polygenic inheritance

14. PULMONIC STENOSIS
In pulmonic stenosis, the right ventricular outflow tract is narrowed,
either at the valve itself, just below it, or just after it.

15. PULMONIC STENOSIS The most common form of pulmonic stenosis involves
a deformed pulmonary valve such that the valve leaflets
are too thick, the opening is too narrow, or the valve cusps
are fused.
The heart must pump extra hard to get blood through
This unusually narrow, stiff valve.
The right ventricle becomes thickened from all this extra work. The right atrium
May become dilated and hypertrophied.

16. CONGENITAL DEFECTS: PULMONIC STENOSIS
Cranial border R side, caudal border is the L side.
NORMAL CANINE CHEST RADS
THIS DOG HAS PULMONIC STENOSIS –
THE HEART LOOKS “PREGNANT” IN THE
FRONT DUE TO RIGHT VENTRICULAR
ENLARGEMENT

17. CONGENITAL DEFECTS: PULMONIC STENOSIS
CLINICAL SIGNS:
Syncope
Tiring on exercise
Right-sided congested heart failure
Left basilar (base) murmur
Right ventricular enlargement
Radiographs: right ventricular enlargement, dilation of the pulmonary artery, pulmonary underperfusion
Echo: right ventricular hypertrophy and enlargement, dilation of the main pulmonary artery
Underperfusion: narrow.

18. PULMONIC STENOSIS: TREATMENT
A special balloon is inserted into the
valve where it is inflated and the
obstruction is broken down.
B blockers: Slow the heart. Relaxation it stretches the heart.
Unfortunately, medical management is not
very beneficial in these cases. Beta-blockers
may be used to relax the heart muscle and
possibly dilate the stenosis.

19. CONGENITAL DEFECTS: SUBAORTIC STENOSIS
Same as above but in the aortic valve.
Newfoundland, Boxer, Golden Retriever, and Bull Terrier are most commonly affected
LESION DEVELOPS IN THE FIRST 4-8 WEEKS OF LIFE

20. CONGENITAL DEFECTS: SUBAORTIC STENOSIS
There is a scar-like narrowing just below the aortic valve. The heart must pump extra hard to get blood through the narrowed area. The blood is pushed through in a turbulent fashion creating a heart murmur.
At base of heart.

21. CONGENITAL DEFECTS: SUBAORTIC STENOSIS
L side heart failure.
THE HARD WORK RESULTS IN LEFT VENTRICULAR HYPERTROPHY, LEFT
ATRIAL ENLARGEMENT, AORTIC DILATION

22. CONGENITAL DEFECTS: SUBAORTIC STENOSIS:
CLINICAL SIGNS:
Fatigue
Exercise intolerance (low cardiac output)
Syncope
Systolic murmur at the left heart base
ECG: evidence of left ventricular enlargement - ↑ QRS height
Echo: left ventricular hypertrophy, subvalvular fibrous ring, aortic dilation

23. CONGENITIAL DEFECTS: SUBAORTIC STENOSIS
TREATMENT
Balloon catheter dilation – has been done with variable and temporary results
Medical management: THE GOAL IS TO SLOW THE HEART RATE AND DECREASE CONTRACTILITY; PROPRANOLOL (BETA-BLOCKER WILL DO THIS)
Propanalol B blocker.

24. CONGENITAL DEFECTS: SUBAORTIC STENOSIS
CLIENT INFO:
Should not be used for breeding
Acute, left-sided congestive heart failure is possible
Sudden death is not uncommon

25. DCM
HCM
PDA
Aortic stenosis
Pulmonic stenosis
1 – dogs
Enlarged Heart bronchile constriction
Dilated Flappy muscle
Nutritional: no taurin in cats
1 – Cats
Saddle thrombus
Rarely in dogs (hereditary)
Noncompliant heart muscle
Aorta – pulmonary a – lungs back L side
Stenotic aortic valve causes LV hypertrophy
High pressure in aortic valve can lead to aortic dilatation
Stenotic pulmonic valve
Pregnant heart
L sided heart failure (HF)
LV hypertrophy
RV hypertrophy
R sided HF
Increased HR
Cough
Weakness in hindlimbs, acute pain, rear cold feet
Pulmonary edema
Sudden death if aorta ruptures
Digoxin: increased contractibility
Beta blocker: Slow HR
Diuretic
Blood thinner
No cure
Treat surgically or die
No breeding
Balloon valvuloplasty