Cardio 2 Flashcards
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?
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.
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in chronic systemic hypertension? And why?
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).
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) 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.
Grain-free diets may be associated with (a) which disease in (b) which domestic species?
(a) Dilated cardiomyopathy in (b) dogs
Fill in the blank: ventricular eccentric hypertrophy is a result of __________ overload.
Volume
Which is the least common form of cardiomyopathy in domestic animals: dilated, hypertrophic or restrictive?
Restrictive
Canine dilated cardiomyopathy may be associated with which type of diet?
Grain-free diets
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?
Right ventricular concentric hypertrophy
Which type of ventricular hypertrophy (concentric or eccentric) would be expected in aortic or pulmonic valvular insufficiency (“leakiness”)? And why?
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).
From which aortic arch should the aorta develop normally?
Left fourth
What are three specialized histologic features of cardiac myocytes that set them apart from other types of muscle cells?
(1) They branch; (2) They have intercalated discs; (3) Some of them are specialized (e.g., Purkinje cells) to form a conducting system
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?
“Frequent regurgitation of food is the most obvious clinical sign.
(1) Cranial megaesophagus; (2) Aspiration pneumonia; (3) Stunting”
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in aortic valvular stenosis? And why?
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).
In which two domestic animal species is dilated cardiomyopathy most common?
Dogs and cats
Fill in the blank: ventricular concentric hypertrophy is a result of __________ overload.
Pressure
Is feline dilated cardiomyopathy more common in females or in males?
Males > females
Name the three most common types of cardiomyopathy seen in domestic animals.
(1) Hypertrophic cardiomyopathy (HCM); (2) Dilated cardiomyopathy (DCM); (3) Restrictive cardiomyopathy
Which type of ventricular hypertrophy (concentric or eccentric; left, right or biventricular) would be expected in hyperthyroidism in cats?
Concentric and biventricular.
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?
Pulmonic stenosis. This is a congenital malformation of the pulmonic valve. The resulting narrowing (stenosis) causes concentric hypertrophy of the right ventricular wall.
Describe the appearance of a transversely sectioned heart with biventricular concentric hypertrophy.
The ventricular myocardium is marked thickened (hypertrophied) and the volume of the ventricular chamber lumen on each side is reduced and sometimes slit-like.
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?
FATE (feline aortic thromboembolism or “saddle thrombus”)
Taurine-deficient diets are associated with (a) which disease in (b) which domestic species?
(a) Dilated cardiomyopathy in (b) cats
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.
“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
“
Feline dilated cardiomyopathy may be associated with which nutritional deficiency?
Taurine deficiency. Supplementation can reverse clinical signs.