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Flashcards in 40 Coronary Regulation Deck (30)
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1

What are the 3 main conduit coronary arteries? Do they contribute to coronary vascular resistance? Are they susceptible to atheroscclerosis?

1. LAD, LCFlex, RC
2. very little
3. They are the site of atherosclerosis

2

What vessels regulates coronary vascular resistance?

resistance vessels- intramural arteries <100micrometers in diameter

3

What develops in response to epicardial stenosis? What are the main stimulus?

1. collateral vessels
2. VEGF, bFGF, PDGF

4

What are veins and venues role in coronary regulation or dysregulation?

They have no role

5

What are the 3 most important factors of regulation for coronary blood flow?

1. metabolic factors
2. Autoregulation
3. Wall tension

[neural regulation, humoral regulation, myogenic tone]

6

Myocardial oxygen consumption/metabolism overrides any other stimulus. What are the 3 major determinants?

contractility, HR, Wall tension [preload and after load]

7

What are the 2 determinants of O2 supply to the heart?

coronary flow
oxygen extraction

8

What is unique about oxygen extraction in the heart?

max at rest and exercise…you must change coronary flow then

9

Where is wall stress greatest? Where is blood flow greatest at rest?

1. greater in endocardium
2. greater in endocardium than epicardium

10

What is auto regulation?

maintaining constant flow with changing perfusion pressure= range in the heart = 40 to 120

11

What is myogenic regulation?

stretch on blood vessel wall produces an increase in smooth muscle contraction---occurs over minutes

12

What does a1 stimulation and a2 stimulation direct effects?

a1=increase epicardial and resistance vessel tone
a2=increase release of NO

13

What are the adrenergic stimulation indirect effects?

1. increase in arterial pressure
2. reflex decrease in HR

14

What is the net effect of alpha adrenergic stimulation? beta?

modest decrease in flow
increase in flow

15

What are direct effects of beta 2? indirect effects of beta 1?

1. decrease epicardial and resistance vessel tone
2. up HR, up contractility, increase MVO2 and vasodilation

16

What are the direct effects of paraSNA? Indirect effects?

1. decrease epicardial and resistance vessel tone
2. down HR, down arterial BP, down MVO2 and vasoconstrict

17

What is the overall paraSNA effect on blood flow?

decrease flow

18

What are ROS effects in cardiovascular disease?

O2- and NO combine to form ONOO- , the decreased NO decreases cGMP which leads to less relaxation

19

What are ROS increased by in regards to vascular dysfunction? 5

atherosclerosis
diabetes
hypertension
AngII
Inflammation

20

What antioxidants may be beneficial?

E and C vitamins NO!!!
SOD/Catalase--maybe but not available

21

How is Rho kinase involved in CV disease?

it is increased, which it inhibits MLC phosphatase, which leads to increased phosphorylation of Myosin light chain which is the contractile state

22

What is angina?

When the O2 supply does not meet the MVO2 demand

[Can happen from a decrease in supply or an increase in demand]

23

CHD, CVD, IHD and angina are all the same and have reduced myocardial perfusion. What are the 3 main causes?

1. coronary artery narrowing with atherosclerosis or plaque
2. Vasospasm (with or without thrombus)
3. Plaque rupture

24

When does maximal flow start diminishing in stenotic patients?

past 50%, but resting flow maintains normal until past 75%

25

What is chronic stable angina?

exertional or typical, fixed atherosclerotic lesions

26

What is variant angina?

vasospasms

27

What is acute coronary syndrome?

1. unstable angina/severe atherosclerosis
2. MI

28

About how many people have silent ischemia?

50%--women more often

29

Average time to seek MI care? Why?

1. 2 hours
2. mismatch of expectations and symptoms

30

What is the approach to CHD treatment?

-increase supply and decr. demand
- decrease work of the heart
-inhibit platelet agg.
-prevent vasospasm
-mechanical interventions