Lecture 22

Question 1

Heart failure

Answer 1

despite adequate venous return, CO is insufficient to meet tissue demands at rest or on physical exertion

Question 2

Signs of heart failure(3)

Answer 2

poor exercise tolerance
shortness of breath
cool extremities

Question 3

early compensated heart failure

arterial BP falls->

Answer 3

destimulated baroreceptors->inc sympathetic activity->inc catecholamines into blood stream

Question 4

Early compensated heart failure
alpha 1 receptors bind

beta 1 receptors bind

Answer 4

->vasoconstriction (arterial)-> inc TPR->inc workload of heart

in myocardium and lead to inc HR and force of contraction->inc workload of the heart

Question 5

early compensated heart failure

how to increase preload/afterload(arrows)

Answer 5

inc sympathetic stimulation->hypothalamus secrete ADH->fluid retention in kidneys->inc blood volume and BP->inc preload and afterload->increased work on failing heart

Question 6

chronically high levels of circulating neuroendocrine hormones (catecholamines, renin, angiotensin, aldosterone) leads to

Answer 6

affecting myocardium directly->structural remodeling long term

Question 7

early compensated heart failure

reduced perfusion to skeletal muscle(2)

Answer 7

atrophy of muscle fibers(cachexia)

exercise intolerance

Question 8

Chronic activation of SNS(2)

Answer 8

dec baroreceptor sensitivity- maintained sympathetic drive even when MAP is normal
down regulation of Beta receptors in the heart-dec capacity of heart to respond to sympathetic stimulation

Question 9

Cardiac hypertrophy(4)

Answer 9

dec mitochondria density-dec energy supply
dec inotropy-weak heart
stiff heart
inc risk of arrythmias

Question 10

Counter regulatory mechanisms in heart failure(2)

Answer 10

atrial naturetic peptide

prostaglandins- antagonize vasoconstrictive effects of angiotensin (to protect kidney)

Question 11

Volume overload leads to

Answer 11

eccentric hypertrophy

Question 12

Eccentric hypertrophy
response to what
what occurs
end stage

Answer 12

response to elevated ventricular end diastolic pressures
ventricular dilation occurs as new sarcomeres are added in series to existing sarcomeres
not enough overlap of actin and myosin

Question 13

pressure overload leads to

Answer 13

concentric hypertrophy

Question 14

concentric hypertrophy
due to
what occurs
end stage

Answer 14

due to chronic pressure overloads (afterload)
ventricular chamber radius may not change, but wall thickness greatly inc as new sarcomeres are added in parallel
capable of generating greater forces and higher pressures

Question 15

Changes in cardiac parameters in heart failure (4)

Answer 15

dec contractility
dec SV
dec exercise tolerance
inc HR- sympathetic NS response to fall in BP

Question 16

dec contractility in end stage eccentric hypertrophy leads to

Answer 16

inc ESV

Question 17

dec filling in concentric hypertrophy leads to

Answer 17

dec EDV