41. Cardiovascular System: Anatomy, Heart Failure, & Congenital Cardiac Defects

What are the functions of the cardiovascular system?

1. M

2. F

1. maintain an adequate and steady supply of nutrients to all organs and tissues of the body

2. facilitate removal of waste products from organs and tissues

a progressive clinical syndrome of impaired pumping of the heart that decreases ventricular ejection thus impeding venous return

heart failure

decreased pumping that results in an inability to maintain arterial pressure

low output heart failure

inability to empty venous reservoirs

congestive heart failure

True or false: There can be a combination of both low output heart failure and congestive heart failure.

true

Heart failure can be either ________ or ________.

acute; chronic

True or false: Congestive heart failure is a clinical syndrome that can be right sided, left sided, or both.

true

What are clinical signs associated with right sided congestive heart failure?

C
A
H
M
S
P

• chronic hepatic passive congestion “nutmeg liver”

• ascites

• hydroperitoneum

• modified transudate (protein rich) peritoneal effusion

• subcutaneous edema

• pleural effusion (in small animals, this is a sign of biventricular CHF)

What clinical sign is associated with left sided congestive heart failure?

pulmonary edema

This is typically associated with what clinical syndrome?

right sided heart failure

What clinical syndrome is this typically associated with?

right sided heart failure

This symptom is commonly associated with what clinical syndrome?

right sided heart failure

What clinical syndrome is this associated with?

left sided heart failure

This is associated with what clinical syndrome?

left sided heart failure

What is a sign of bilateral (right and left sided) congestive heart failure in small animals?

pleural effusion

This is typically associated with what clinical syndrome?

bilateral congestive heart failure

increase in muscle mass due to increased size of cardiac muscle cells

myocardial hypertrophy

What are the two forms of myocardial hypertrophy?

C
E

• concentric hypertrophy

• eccentric hypertrophy

form of myocardial hypertrophy in which the myocardium thickens, narrowing the ventricular lumen

concentric hypertrophy

In concentric hypertrophy, what is the hypertrophied ventricle prone to? What does this lead to?

ischemia; fibrosis

Concentric hypertrophy occurs with what?

pressure overload

form of myocardial hypertrophy in which there is an increase in the length of the myofibers

eccentric hypertrophy

What will eccentric hypertrophy result in?

ventricular dilation with normal to decreased wall thickness

What does eccentric hypertrophy occur with?

volume overload

What are the two main causes for congen

What are other causes for congenital cardiac malformations?

D
X
F
M

• drug or toxic compound induced

• x-irradiation

• fetal hypoxia

• maternal nutritional imbalances

What are common drugs/toxins that can cause congenital cardiac malformations?

salicylates (in aspirin) and griseofulvin

What is a specific maternal nutritional imbalance that can lead to congenital cardiac malformations?

vitamin A deficiency/excess

What results in volume overload of the pulmonary circuit? What will this lead to?

left to right shunting; left atrial and ventricular eccentric hypertrophy

Which congenital cardiac malformations result in volume overload?

V
P
P
A

• ventricular septal defect

• patent foramen ovale

• patent ductus arteriosus

• atrial septal defect

What is the most common congenital cardiac defect of cattle and horses?

ventricular septal defect

What are the two types of ventricular septal defects?

high and low

ventricular septal defect that is located just below the aortic semilunar valves and is most common

high defect

ventricular septal defect that is closer to the apex of the heart

low defect

What is this showing?

ventricular septal defect

What is this showing?

high and low ventricular septal defect

What is the most common congenital cardiac defect in small ruminants?

patent foramen ovale

one of the two pulmonary bypases in a fetus that connects the right atrium to the left atrium and is best visualized by opening the caudal vena cava ostia that closes after birth with a small flap of connective tissue, which covers the opening due to the pressure change of taking a first breath

foramen ovale

What is this showing?

patent foramen ovale

What is the most common congenital cardiac defect in dogs?

patent ductus arteriosus

the second pulmonic fetal bypass to the lungs that connects the main pulmonary artery to the aorta

ductus arteriosus

failure of the closure of the ductus arteriosus

patent ductus arteriosus

What is this showing?

patent ductus arteriosus

What is this showing?

patent ductus arteriosus

What is the second most common septal defect in cattle

atrial septal defect

What are the two types of atrial septal defects? Which is most common?

septum primum and septum secundum; septum secundum

atrial septal defect that is adjacent to the foramen ovale

septum primum

atrial septal defect that is in the mid atrial septum

septum secundum

What is this showing?

atrial septal defect

In congenital cardiac malformations that result in pressure overload, what will ventricular outflow obstruction lead to? This will then lead to what?

progressive increase in intraventricular pressure; concentric ventricular hypertrophy

What are the congenital cardiac malformations that result in pressure overload?

P
S

• pulmonic stenosis

• subaortic stenosis

What is the second most common congenital cardiac malformation in dogs?

pulmonic stenosis

development of a dense band of fibrous muscular tissue below the pulmonic semilunar valves with or without malformation of the valve

pulmonic stenosis or subaortic stenosis

What is this showing?

pulmonic stenosis

What is the most common congenital cardiac malformation in the pig and the third most common malformation in the dog?

subaortic stenosis

What is this showing?

subaortic stenosis

What congenital cardiac diseases result in cyanosis and collapse due to reduced cardiac output?

T
T

• tricuspid/mitral valvular dysplasia

• tetralogy of fallot

What is the most common congenital cardiac defect in cats and is also frequently seen in pigs?

tricuspid/mitral valvular dysplasia

Is mitral or tricuspid valvular dysplasia more common?

tricuspid

Valvular dysplasia can be a combination of what?

1. S

2. I

3. E

4. D

5. A

1. shortened, rolled, or notched valves

2. incomplete separation of the valve leaflets from the wall

3. elongation, shortening, fusion, or thickening of the chordae tendinae

4. direct insertion of the valve into a papillary muscle

5. atrophy, fusion, or malpositioning of the papillary muscles

True or false: Valvular dysplasia can be seen in conjunction with septal defects.

true

What is this showing?

tricuspid/mitral valvular dysplasia

Tetralogy of fallot is ________ in all species and comprises ________ lesions.

uncommon; four

What are the four lesions that comprise tetralogy of fallot?

1. H

2. D

3. P

4. R

1. high VSD

2. dextroposition of the aorta (aorta connecting to RV outflow tract)

3. pulmonic stenosis

4. right ventricular hypertrophy

What is this showing?

tetralogy of fallot

vascular ring anomaly that is a failure of regression during fetal development

persistent right aortic arch (PRAA)

With a persistent right aortic arch (PRAA), what is there entrapment of? What does this cause? This will then lead to what? Ultimately, what does this result in?

esophagus and trachea; megaesophagus; regurgitation; aspiration pneumonia

What is this showing?

persistent right aortic arch (PRAA)