Cardio 12

Question 1

Describe heart failure.

Answer 1

-pathophysiological state where the heart is impaired in the ability to eject or receive blood
>physical disability w clinical signs that vary with cause & between species
>weakness, lethargy, exercise intolerance
>right X left side congestive heart failure

Question 2

What can heart failure result from?

Answer 2

-heart valve dis function
-arrythmias
-myocardial disease
-pericardial disease
-increased resistance to ejection

Question 3

What are the 4 functional classifications of heart failure?

Answer 3

1. Impeded cardiac filling
2. Increased resistance to ejection of blood (afterload)
3. Impaired ejection or volume overload
4. Arrhythmias & conduction disorders

Question 4

Describe impeded cardiac filling.

Answer 4

-pericardial disease with restricted filling
(Ex: pericardial effusion)
-valvular inflow obstruction
(ex: AV valve stenosis)
-intrinsic myocardial disease with impaired diastolic function
(Ex: hypertrophic cardiomyopathy)

Question 5

Describe increased resistance to ejection of blood (afterload).

Answer 5

Ex: pulmonic or aortic stenosis; pulmonary hypertension

Question 6

Describe impaired ejection or volume overload.

Answer 6

-primary & secondary myocardial disease with impaired systolic function
>ex: dilated cardiomyopathy
-misdirected blood flow = volume overload
>ex: valvular insufficiency

Question 7

Describe arrhythmias & conduction disorders.

Answer 7

-sustained tachyarrhythmias
>supraventricular tachycardia
>atrial fibrillation
-chronic bradyarrhythmias
>complete heart block

Question 8

Describe compensatory mechanisms.

Answer 8

-when CO falls = BP falls = triggers compensatory mechanisms
-beginning = beneficial then contribute to clinical signs of heart failure

Question 9

Which fast mechanism is activated & responds after a fall in BP?

Answer 9

-baroreflex

Question 10

Describe neurohumoral responses.

Answer 10

-begin with detection of decrease in MAP by arterial baroreceptors
-increase sympathetic activity to heart, peripheral arterioles & veins
>vasoconstriction to skin, kidneys, spleen, resting muscles, mucosa
-decrease parasympathetic tone
>increase HR

Question 11

Which receptors are involved with increase in sympathetic tone to the heart?

Answer 11

-beta adrenergic B1

Question 12

Which receptors are involved with enhanced sympathetic outflow, vasoconstriction, & increase of TPR?

Answer 12

-alpha adrenergic A1&A2

Question 13

Describe how the arterial baroreflex becomes counterproductive.

Answer 13

-Initially the arterial baroreflex maintains BP but as heart failure progresses & CO declines = counterproductive
-tissue ischemia to non vital organs
>skin, spleen, & kidneys = reduced perfusion activates RAAS
-rise in TPR = reduces SV

Question 14

Why does the increase in TPR reduce SV?

Answer 14

-increase in afterload

Question 15

Describe what happens when there’s an increase in blood volume.

Answer 15

-initially increase SV bc of frank starling mechanism
>compensates for low pumping ability of heart by increasing venous return

Question 16

What are the volume overload physiological consequences?

Answer 16

-increase workload of heart
-overstretching of heart = weakens
>chronic excess stretch on actin-myosin cross bridges
>decreased ability to generate force of contraction
cardiac enlargement

Question 17

Volume overload will increase capillary hydrostatic pressure. What is the consequence?

Answer 17

Movement of fluid from capillary to interstitial space

Question 18

What happens when a failing ventricle is unable to pump all the blood returned to it?

Answer 18

-veins behind the failing ventricle becomes congested with blood
>filtration of fluid into lungs = pulmonary edema
>extensive edema in parts of the body
*increased venous congestion & capillary hydrostatic pressure
*pulmonary & systemic congestion

Question 19

Describe L & R heart failure.

Answer 19

Question 20

What are other neuroendocrine responses?

Answer 20

-induce alterations in heart failure
>natriuertic peptides (atrial, brain & C type)
>endothelin
>adrenomedullin (produced by adrenal medulla, heart, lungs, kidneys)
vasodilator & natriuretic action
>cytokine & integrins signaling
important role in inflammation ex. Myocarditis

Question 21

Describe angiotensin II in heart failure.

Answer 21

-stimulates vascular & cardiac remodeling
>myocyte growth
>sm muscle growth
>collagen
cardiac & vascular hypertrophy

Question 22

What is the vascular remodeling part of?

Answer 22

Long term control of local blood flow

Question 23

What is the mechanism designed for acute loss in CO?

Answer 23

chronic activation of mechanism worsen the heart failure