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VETM 425 Sys Path > Lecture 7: CDV 2 > Flashcards

Lecture 7: CDV 2 Flashcards

1
Q

You are performing a necropsy on a dog and find that the left ventricle has a markedly thickened wall. In addition, its outflow valve has a band of fibrous tissue immediately proximal to it. What are you most likely seeing?

A

Subaortic stenosis. This is a congenital malformation where a ring of fibrous tissue encircles the left ventricular outflow tract beneath the aortic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the left ventricular wall.

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2
Q

Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic systemic hypertension? And why?

A

Concentric and left. Systemic hypertension causes PRESSURE overload in the left side of the heart. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).

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3
Q

Chronic pulmonary hypertension may result in right ventricular concentric hypertrophy. What is a fairly common disease that causes this in (a) dogs, (b) cattle and (c) horses?

A

“(a) Dogs: “Heartworm disease” (dirofilariasis), where
nematodes live in the pulmonary arteries, pulmonary trunk and right atrium.
(b) Cattle: “Brisket disease” (high altitude disease), where
cattle above 7000 feet develop right-sided heart failure.
(c) Horses: “Heaves” (chronic alveolar emphysema), which is an asthma-like condition. “

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4
Q

Grain-free diets may be associated with (a) which disease in (b) which domestic species?

A

(a) Dilated cardiomyopathy in (b) dogs

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5
Q

Fill in the blank: ventricular eccentric hypertrophy is a result of __________ overload.

A

Volume

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6
Q

Which is the least common form of cardiomyopathy in domestic animals: dilated, hypertrophic or restrictive?

A

Restrictive

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7
Q

Canine dilated cardiomyopathy may be associated with which type of diet?

A

Grain-free diets

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8
Q

Aside from the valvular malformation itself, what is the most prominent lesion you would expect in the heart of a dog with congenital pulmonic stenosis?

A

Right ventricular concentric hypertrophy

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9
Q

Which type of ventricular hypertrophy (concentric or eccentric) would be expected in aortic or pulmonic valvular insufficiency (“leakiness”)? And why?

A

Eccentric. Valvular insufficiency (“leakiness”) results in backflow of blood into an already full heart chamber. This is VOLUME overload. Volume overload leads to chamber dilation, or ECCENTRIC hypertrophy. (In contrast, concentric hypertrophy is associated with PRESSURE overload).

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10
Q

From which aortic arch should the aorta develop normally?

A

Left fourth

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11
Q

What are three specialized histologic features of cardiac myocytes that set them apart from other types of muscle cells?

A

(1) They branch; (2) They have intercalated discs; (3) Some of them are specialized (e.g., Purkinje cells) to form a conducting system

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12
Q

What clinical sign is noticed first by owners of dogs suffering from persistent right aortic arch (PRAA)? What are three other, less spectacular but still important clinical effects or lesions of PRAA?

A

“Frequent regurgitation of food is the most obvious clinical sign.
(1) Cranial megaesophagus; (2) Aspiration pneumonia; (3) Stunting”

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13
Q

Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in aortic valvular stenosis? And why?

A

Concentric and left. Aortic stenosis causes PRESSURE overload in the left ventricle. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).

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14
Q

In which two domestic animal species is dilated cardiomyopathy most common?

A

Dogs and cats

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15
Q

Fill in the blank: ventricular concentric hypertrophy is a result of __________ overload.

A

Pressure

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16
Q

Is feline dilated cardiomyopathy more common in females or in males?

A

Males > females

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17
Q

Name the three most common types of cardiomyopathy seen in domestic animals.

A

(1) Hypertrophic cardiomyopathy (HCM); (2) Dilated cardiomyopathy (DCM); (3) Restrictive cardiomyopathy

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18
Q

Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in hyperthyroidism in cats?

A

Concentric and biventricular.

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19
Q

You are performing a necropsy on a dog and find that the right ventricle has a markedly thickened wall. In addition, its outflow valve is malformed and has a band of fibrous tissue immediately proximal to it. What are you most likely seeing?

A

Pulmonic stenosis. This is a congenital malformation of the pulmonic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the right ventricular wall.

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20
Q

Describe the appearance of a transversely sectioned heart with biventricular concentric hypertrophy.

A

The ventricular myocardium is marked thickened (hypertrophied) and the volume of the ventricular chamber lumen on each side is reduced and sometimes slit-like.

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21
Q

Both feline hypertrophic cardiomyopathy and hyperthyroidism cause cardiac changes predisposing to turbulence and the formation of thrombi within the heart. What is a common sequela of this thrombosis?

A

FATE (feline aortic thromboembolism or “saddle thrombus”)

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22
Q

Taurine-deficient diets are associated with (a) which disease in (b) which domestic species?

A

(a) Dilated cardiomyopathy in (b) cats

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23
Q

Describe the gross appearance of the heart of a dog that died from dilated cardiomyopathy. Try to name three lesions, not just the single obvious one.

A

“Rounded heart with biventricular dilation. Markedly dilated cardiac chambers; these make the walls appear relatively thin in comparison but it is important to remember that they are still hypertrophic. Diffuse endocardial fibrosis -> thick, white lining in chambers
“

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24
Q

Feline dilated cardiomyopathy may be associated with which nutritional deficiency?

A

Taurine deficiency. Supplementation can reverse clinical signs.

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25
Q

You are performing a necropsy on a cat that died from heart failure. You note marked concentric hypertrophy of the left ventricular wall and interventricular septum that results in severe reduction of the left ventricular lumen. What is the most likely diagnosis?

A

Hypertrophic cardiomyopathy

26
Q

Name two diseases of cats that can predispose to FATE (feline aortic thromboembolism or “saddle thrombus”).

A

(1) Hypertrophic cardiomyopathy and (2) hyperthyroidism

27
Q

Describe the (a) appearance and (b) function of an AV valve affected by congenital atrioventricular valve dysplasia.

A

(a) AV valve leaflets and chordae tendineae are short and thickened; (b) Incompetent valve function -> regurgitation of blood [-> heart failure]

28
Q

Is canine dilated cardiomyopathy more common in females or in males?

A

Males > females

29
Q

Describe the pathogenesis of feline restrictive cardiomyopathy.

A

Severe endocardial fibrosis (possibly caused by end stage endomyocarditis) -> impaired diastolic relaxation -> reduced ventricular filling (decreased preload) -> decreased cardiac output [->] heart failure

30
Q

In which domestic animal species is restrictive cardiomyopathy most common?

A

cats

31
Q

What does the term cor pulmonale mean?

A

Right-sided heart failure caused by chronic pulmonary hypertension

32
Q

Describe the appearance of a transversely sectioned heart with biventricular eccentric hypertrophy.

A

The ventricular myocardium is thickened (hypertrophied) but this is overshadowed by marked enlargement (dilation) of the ventricular chamber lumen on each side. Because of this chamber dilation the myocardium may appear relatively thinned, but it is still hypertrophied.

33
Q

Fill in the blank: cardiac ventricular volume overload results in __________ hypertrophy.

A

Eccentric

34
Q

Which feline cardiomyopathy is more common in OLDER cats: dilated or hypertrophic?

A

Dilated cardiomyopathy

35
Q

Fill in the blank: cardiac ventricular pressure overload results in __________ hypertrophy.

A

Concentric

36
Q

Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in pulmonic valvular stenosis? And why?

A

Concentric and right. Pulmonic stenosis causes PRESSURE overload in the right ventricle. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).

37
Q

Aside from the valvular malformation itself, what is the most prominent lesion you would expect in the heart of a dog with congenital subaortic stenosis?

A

Left ventricular concentric hypertrophy

38
Q

What is the term for the developmental anomaly where the heart develops at an abnormal site outside of the thoracic cavity?

A

Ectopia cordis. The most common ectopic location is subcutaneously in the caudoventral neck, just cranial to the thoracic inlet.

39
Q

What is a common and frequently fatal NON-cardiac complication of hypertrophic cardiomyopathy in cats?

A

Secondary caudal abdominal aortic thromboembolism (“saddle thrombus”) in ~20% of cases

40
Q

What are valvular hematocysts, where are they most commonly found, and in which domestic species?

A

These are bulging blood-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.

41
Q

You are performing a necropsy on a calf and find a clear 7 mm diameter spherical cyst on the free edge of the left AV valve. What is this and what is its significance?

A

A valvular lymphocyst. These are bulging lymph-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.

42
Q

In the condition persistent right aortic arch, what specific structure causes esophageal entrapment and stenosis?

A

The ligamentum arteriosum

43
Q

What is the term for right-sided heart failure caused by chronic pulmonary hypertension?

A

Cor pulmonale

44
Q

You are performing a necropsy on a calf and find a dark purple 7 mm diameter spherical cyst on the free edge of the left AV valve. What is this and what is its significance?

A

A valvular hematocyst. These are bulging blood-filled cysts along the free edges of AV valves, most commonly seen in young ruminants. They cause no functional abnormalities and regress spontaneously. They should not be misinterpreted as valvular endocarditis.

45
Q

Which (a) endocrine disease in (b) which domestic species may cause cardiac lesions resembling those of hyeprtrophic cardiomyopathy?

A

(a) Hyperthyroidism in (b) cats

46
Q

Describe the pathogenesis of the condition persistent right aortic arch, from causal developmental abnormality to production of the most common clinical signs and lesions.

A

Aorta develops abnormally from the right 4th aortic arch instead of the left 4th aortic arch -> this creates a vascular ring with the ligamentum arteriosum (which developed normally from the left 6th aortic arch) -> the esophagus passes through and is entrapped by this vascular ring -> esophageal narrowing at this point -> frequent regurgitation of food [+/- cranial megaesophagus, aspiration pneumonia and stunting]

47
Q

Which feline cardiomyopathy is more common in YOUNGER cats: dilated or hypertrophic?

A

Hypertrophic cardiomyopathy

48
Q

You are performing a necropsy on a dog that died from heart failure. You note: (a) a rounded heart with biventricular dilation, (b) markedly dilated cardiac chambers, and (c) diffuse endocardial fibrosis resulting in a thick, white lining in all chambers. What is the most likely diagnosis?

A

Dilated cardiomyopathy

49
Q

What is the typical (a) signalment and (b) clinical presentation for a cat with hypertrophic cardiomyopathy?

A

(a) Young, adult male. Possibly Maine Coon breed; (b) sudden death or congestive heart failure

50
Q

Hyperthyroidism in cats may cause cardiac enlargement resembling hypertrophic cardiomyopathy. Explain why this cardiac enlargement is NOT classified as cardiomyopathy.

A

Cardiomegaly seen in feline hyperthyroidism is due to enhanced production of myocardial contractile proteins under the influence of increased concentration of circulating thyroid hormones. This is reversible if thryoid hormone levels are returned to normal. It is NOT a primary disease of the myocardium; it has an extra-cardiac cause. On the other hand, HCM IS a primary myocardial disease and is not reversible.

51
Q

In which domestic animal species is hypertrophic cardiomyopathy most common?

A

Cats (»> dogs)

52
Q

Describe the gross appearance of the heart of a cat that died from hypertrophic cardiomyopathy.

A

Marked concentric hypertrophy of left ventricular wall and interventricular septum -> severe reduction of ventricular lumen

53
Q

Do cardiac myocytes undergo (a) hyperplasia or (b) hypertrophy in response to increased workload?

A

(b) Hypertrophy

54
Q

What is the most common vascular ring anomaly in dogs?

A

Persistent right aortic arch

55
Q

In cases of persistent right aortic arch, from which aortic arch did the aorta develop?

A

Right fourth

56
Q

Which canine congenital cardiac developmental disorder is most likely in a stunted young dog with frequent regurgitation of food?

A

Persistent right aortic arch

57
Q

Which dog breeds are particularly predisposed to development of dilated cardiomyopathy?

A

Large breeds: Doberman pinschers especially predisposed. Also Irish wolfhounds, St. Bernards, great Danes etc. although any breed can be affected.

58
Q

Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic pulmonary hypertension? And why?

A

Concentric and right. Pulmonary hypertension causes PRESSURE overload in the right side of the heart. Pressure overload results in CONcentric hypertrophy. (In contrast, eccentric hypertrophy is associated with VOLUME overload).

59
Q

Which canine congenital cardiac developmental anomaly is associated with esophageal obstruction?

A

Persistent right aortic arch

60
Q

What is ectopia cordis?

A

A developmental anomaly where the heart develops at an abnormal site outside of the thoracic cavity. The most common ectopic location is subcutaneously in the caudoventral neck, just cranial to the thoracic inlet.

61
Q

Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in a ventricular septal defect? And why?

A

Eccentric and right. Ventricular septal defects result in blood crossing into an already full right ventricle. Blood moves left to right rather than right to left because the pressure in the left ventricle exceeds pressure in the right ventricle. This is VOLUME overload. Volume overload leads to chamber dilation, or ECCENTRIC hypertrophy. (In contrast, concentric hypertrophy is associated with PRESSURE overload).

VETM 425 Sys Path (15 decks)

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