Cardiovascular Pathology

T

T or F: Cardiac hypertrophy and dilation are beneficial to a point

Eccentric

Chronic volume overload leads to what type of hypertrophy?

Exercise and pregnancy

What are stimuli for physiological cardiac hypertrophy?

F

T or F: Physiological hypertrophy causes depressed cardiac function

Aortic stenois, mitral regurgitation, etc.

What are stimuli for pathological cardiac hypertrophy?

Primary cardiac hypertrophy

Absence of known cause and other cardiac conditions,

inherited non-sex-linked genetic trait

Secondary cardiac hypertrophy

Due to sustained increase in cardiac workload (volume or pressure overload)

Concentric

Chronic pressure overload leads to what type of hypertrophy?

Preload

Valvular insufficiency increases the ___________ on the ventricles

Afterload

Semilunar valvular stenosis, outflow tract stenosis and hypertension increase the ___________ on the ventricles

Decrease

AV valvular stenosis and pericardial diseases __________ the preload on the ventricles

A. Eccentric

B. Concentric

ID type of cardiac hypertrophy for:

A. Left

B. Right

1. Initiation

2. Compensation

3. Deterioration

What are the cellular stages of cardiac hypertrophy?

Initiation

Cellular stage of cardiac hypertrophy characterized by increase in cell size (sarcomeres/mitochondria)

Compensation

Cellular stage of cardiac hypertrophy characterized by stable hyperfunction (no clinical signs)

Deterioration

Cellular stage of cardiac hypertrophy characterized by degeneration of hypertrophied cardiomyocytes (loss of ventricular contractility or compliance)

Blood vessels (which deliver oxygen to cardiomyocytes)

During initiation of cardiac hypertrophy, the cell size increases; however, what does not increase leading to hypoxia/necrosis?

Broad base

What gross change is apparent due to right cardiac hypertrophy?

Increased length

What gross change is apparent due to left cardiac hypertrophy?

Globose (rounded)

What gross change is apparent due to bi-ventricular hypertrophy?

D, G

If a patient has a heart that is gross in appearance as shown in the picture, what are some underlying causes? (Multiple answers apply)

A. Mitral valve disease

B. DCM

C. Aortic stenosis

D. Pulmonary hypertension

E. HCM

F. VSD

G. Pulmonic stenosis

A, C, E

If a patient has a heart that is gross in appearance as shown in the picture, what are some underlying causes? (Multiple answers apply)

A. Mitral valve disease

B. DCM

C. Aortic stenosis

D. Pulmonary hypertension

E. HCM

F. VSD

G. Pulmonic stenosis

B, F

If a patient has a heart that is gross in appearance as shown in the picture, what are some underlying causes? (Multiple answers apply)

A. Mitral valve disease

B. DCM

C. Aortic stenosis

D. Pulmonary hypertension

E. HCM

F. VSD

G. Pulmonic stenosis

0.5-1.0

Hearts should be ___________% of the body weight

18 grams

In cats, if the heart weighs more than ____________ it is hypertrophied, irrespective of body weight

Ductus venosus

Connects the umbilical vein to the inferior vena cava, bypassing the liver

Foramen ovale

Connects the two atria in the fetal heart, bypassing the lungs

Ductus arteriosus

Connects the pulmonary artery to the aorta, bypassing the lungs

1. Patent ductus arteriosus (PDA)

2. Atrial septal defect (ASD)

3. Ventricular septal defect (VSD)

What are the three examples of left to right shunts?

Patent ductus arteriosus

Failure of the ductus arteriosus to close after birth, resulting in an abnormal opening between the pulmonary artery and the aorta

1. Blood shunts from left to right via PDA

2. Increases blood flow to the lung

3. Increases venous return to the LA & LV

4. Volume overload of LV

5. LV eccentric hypertrophy

Describe the hemodynamics of PDA

1. Blood shunts left to right via PDA

2. Increases blood flow to the lung

3. Pulmonary hypertension

4. Pressure overload of RV

5. RV concentric hypertrophy

Describe the hemodynamics of rare cases of PDA

Atrial septal defect

Congenital defect in the septum dividing the left and right atria

Dogs and cattle

ASD is most common in what species?

1. Blood shunt from LA to RA

2. Increase in blood volume in the right ventricle

3. Volume overload of RV

4. RV eccentric hypertrophy

Describe the hemodynamics of ASD

Ventricular septal defect

Congenital opening in the septum separating the ventricles

Horses and cattle

VSD is most common in what species?

High VSD

Defect in the membranous portion of the septum

Low VSD

Defect in the muscular portion of the septum

High

Is a high or low VSD more common?

1. Blood shunt from LV to RV

2. Increase in blood volume in the RV

3. Equalization of pressure across the ventricles

4. LV hypertrophy and RV hypertrophy

Describe the hemodynamics of VSD

Eisenmenger complex

Shunt reversal

Stenosis

Narrowing of the valve orifice

Valvular

What type of pulmonic stenosis is most common in dogs?

1. Stenotic valve restricts outflow

2. Pressure overload of RV

3. RV concentric hypertrophy

4. Right heart failure

Describe the hemodynamics of pulmonic stenosis

1. Stenotic valve restricts outflow

2. Pressure overload of LV

3. LV concentric hypertrophy

(If severe can lead to arrhythmias and sudden cardiac death, left heart failure)

Describe the hemodynamics of subaortic stenosis (SAS)

Cats

Cardiomyopathies are most common in what species?

1. Hypertrophic cardiomyopathy

2. Dilated (congestive) cardiomyopathy

3. Restrictive (infiltrative) cardiomyopathy

What are the three classifications of primary cardiomyopathies?

Hypertrophic cardiomyopathy

What is the most common form of feline cardiomyopathy?

1. Left side heart failure

2. Pulmonary edema

3. Dyspnea

Describe how hypertrophic cardiomyopathy lead to dyspnea?

Myosin binding protein c

Mutations in the cardiac protein called ____________________ can lead to feline HCM

Symmetrical

If both the septum and free wall are affected in feline HCM, it is considered what?

Diastolic (ventricle cannot fill properly)

Feline HCM causes impaired (systolic or diastolic) function

Myofibers are in disarray with interstitial fibrosis present

Why is the image on the left not normal myocardium?

1. Severe atrial enlargement (because blood cannot flow to left ventricle)

2. Caudal abdominal aorta (saddle thrombus)

What are some sequelae of feline HCM?

Dilated cardiomyopathy

All chambers enlarged, ventricles are dilated, flabby with thin walls

Taurine

A _____________ deficiency leads to myocardial failure (dilated cardiomyopathy)

Systolic

Dilated cardiomyopathy causes impaired (systolic or diastolic) function

Diastolic

Restrictive cardiomyopathy causes impaired (systolic or diastolic) function

Young to middle aged, large breed dogs (St. Bernard, Great Dane)

Dilated cardiomyopathies are common in what canine breeds?

Striatin

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is common in Boxers and caused by a mutation in what gene?

Right ventricle

ARVC can lead to ventricular arrhythmia of _________ origin

Pericardium

A double-layered serous membrane that surrounds the heart

Hydropericardium

Transudate in the pericardial sac

1. Increases in hydrostatic pressure: right heart failure

2. Hypoproteinemia: emaciation, protein losing enteropathy/nephropathy

What is the pathogenesis of hydropericardium?

Hemopericardium

Blood in the pericardial cavity

1. Cardiac puncture

2. Aortic rupture

3. Ulcerative atrial endocarditis

4. Atrial hemangiosarcoma in dogs

What are causes for hemopericardium?

Horses and turkeys

Aortic rupture leading to hemopericardium is most common in what species?

Atrial hemangiosarcoma

What is the most common cause for hemopericardium in dogs?

Cardiac tamponade

Acute compression of the heart caused by fluid accumulation in the pericardial cavity

Diastolic filling

Cardiac tamponade may prevent what?

Serous atrophy of pericardial fat

Epicardial fat appears gelatinous

Emaciation

Serous atrophy of pericardial fat occurs due to what?

BCS

Serous atrophy of pericardial fat is indicative of poor what?

Fibrinous pericarditis

Pericardial sac contains effusion rich in fibrin that clots soon after exposure to air

Vascular

Fibrinous pericarditis is reflective of ____________ disease

Fibrinous pericarditis

FIP in cats leads to what pericardial disease?

"Shaggy heart" or "bread and butter heart"

What are names given for fibrinous pericarditis?

Purulent pericarditis

Pericarditis where pericardial space is invaded by infection that enters due to neighboring inflammation

Traumatic reticulopericarditis

Uncommon consequence of hardware disease due to penetration of a sharp metal object from the reticulum into the pericardium

Chronic constrictive pericarditis

What is the ultimate fate of purulent and fibrinous pericarditis?

Chronic constrictive pericarditis

A fibrous thickening of the pericardium that prevents adequate filling of the ventricles (diastolic dysfunction) and eventually results in cardiac failure

1. Ischemic

2. Toxic

3. Nutritional

4. Neurogenic

Myocardial necrosis is due to what?

Brain-heart syndrome

Injury to brain can cause myocardial necrosis due to catecholamine surge

Vitamin E and selenium

Nutritional myocardial necrosis is due to deficiencies in what?

F (common in humans)

T or F: Myocardial necrosis due to ischemia is common in animals

1. Coagulative necrosis

2. Infiltration of leukocytes

3. "Healing" begins (fibroblast proliferation)

What are the steps of myocardial necrosis?

T

T or F: There is no regenerative power of myocardium in adults

1. Loss of cross striations

2. Karyolysis

Acute myocardial necrosis (12-24 hours) is characterized by what microscopically?

Macrophages and neutrophils infiltrate and phagocytize necrotic debris

Acute myocardial necrosis (2-3 days) is characterized by what microscopically?

1. Fibrosis

2. Mineralization

Myocardial fibrosis (> 12-20 days) is characterized by what microscopically?

Monensin toxicity

Incredibly toxic in horses causes myocardial degeneration and necrosis in left ventricle

Ionophores and Doxorubicin

What are some important toxins that cause toxic myocardial necrosis?

White muscle disease

Nutritional myopathy due to vitamin E or selenium deficiency

Young farm animals

White muscle disease typically affects what group of animals?

T

T or F: White muscle disease can affect skeletal muscle, or cardiac muscle, and sometimes both

1. Selenium and vitamin E deficiency

2. Free radicals are produced during normal cardiac metabolism

3. Decreased scavenging of free radicals

4. Peroxidation of cell membranes

5. Cardiac and skeletal muscle necrosis and mineralization

Describe the mechanism of white muscle disease

Left ventricle

White muscle disease of calves typically affects what?

Right ventricle

White muscle disease of lambs typically affects what?

T

T or F: Myocarditis rarely occurs alone, it is typically part of a systemic disease