Coronary Artery A&p

Front 1

wall separating the lower chambers (the ventricles) of the heart from one another.

Back 1

interventricular septum

Front 2

The atria of the heart are separated from the ventricles by the ________________.

Back 2

atrioventricular groove.

Front 3

outer layer of heart tissue, mostly CT.

Back 3

epicardium

Front 4

innermost layer of tissue that lines the chambers of the heart.

Back 4

endocardium

Front 5

Left main coronary artery bifurcates into what two branches (usually)?

Back 5

Left anterior descending (LAD)

Left Circumflex (LCx)

Front 6

In 20% of cases, what is the 3rd branch of the left main coronary ?

Back 6

A ramus intermediate branch

Front 7

3 major branches of the LAD and what they supply

Back 7

1) Septal perforators : dive into interventricular septum

2) Diagonal branches : anterolateral surface of LV

3) Right ventricular branches - part of RV myocardium, but major supply to RV is usually R coronary.

Front 8

What 3 segments (pretty specific) is the LAD divided into?

Back 8

Proximal, Apical, and mid-LAD

1) Proximal: portion before the origin of the first major septal perforators

2) Apical: begins at origin of 2nd major diagonal branch from LAD

3) mid-LAD: between these two

Front 9

portion of LAD before the origin of the first major septal perforators

Back 9

proximal

Front 10

portion of LAD that begins at origin of 2nd major diagonal branch from LAD

Back 10

apical

Front 11

portion of LAD between proximal and apical

Back 11

mid

Front 12

The left circumflex artery after branching from the L main extends laterally in the ___________

Back 12

left atrioventricular groove

Front 13

Branches of left circumflex artery that supply the left ventricle are __________

Back 13

obtuse marginal

Front 14

In 15% of cases, the left circumflex artery is the dominant vessel. It extends to the crux cordis and gives rise to the _____________ that supplies the inferior portion of interventricular septum

Back 14

posterior descending artery

Front 15

6 branches typically given off by R coronary artery

Back 15

1) Sinoatrial node artery - 60%
2) Conus artery
3) Acute marginal
4) Atrial branches
5) Posterior descending
6) Posterolateral branches (highly variable)

Front 16

Supplies majority of right ventricle

Back 16

Right coronary artery

Front 17

Channels that can provide alternate/supplemental sources of blood flow, become especially important when a blockage occurs

Back 17

Collateral coronary circulation

Front 18

What happens when both coronary arteries arise from the pulmonary trunk?

Back 18

Incompatible with life

Front 19

What happens when the left main artery originates from the pulmonary trunk?

Back 19

Most die in first year of life. Some survive into adulthood, but survival depends on development of collateral circulation from R coronary artery.

Incidence of sudden death is high. Have continuous murmur.

Front 20

junction of the atrioventricular groove and the posterior interventricular sulcus

Back 20

crux cordis

Front 21

Left or right coronary artery dominance is determined by the _______

Back 21

origin of the posterior descending / aka posterior interventricular artery

Front 22

The atrioventricular node artery originates from the RCA in approximately __% of the population and LCx coronary artery in _%.

Back 22

90; 10

Front 23

Most people are (left, right) heart dominant

Back 23

Right (70%)

Front 24

What happens when the right coronary artery originates from the pulmonary trunk?

Back 24

less common than origin of left main, less serious, most people with this survive to adulthood.

Most are asymptomatic.

Better prognosis because less myocardium is in jeopardy when the RCA relies on the Left coronary for collateral flow.

Front 25

Left main artery normally originates from the Left aortic sinus. What happens if it arises from the R?

Back 25

a major cause of extertional syncope and angina in young patients.

Associated with sudden death, correlated with vigorous exertion.

Front 26

2 major mechs of ischemia when the left main artery originates from the right aortic sinus

Back 26

1) It can get compressed between aorta and pulmonary artery which expand during exercise.

2) It will angulate at its origin, with compromise of ostial lumen or channel.

Front 27

Most common coronary anomaly (1-2% incidence)

Back 27

Left circumflex originates from the right aortic cusp. Not associated with significant consequences. When present, it goes posterior so it doesn't get trapped.

Front 28

What happens when the right coronary artery comes out of the left aortic sinus?

Back 28

More benign in comparison to L main coming out of R side, but sudden death and other problems have been reported.

Front 29

Flow =

Back 29

Pressure / Resistance

Front 30

Sympathetic activation elicits an (increase, decrease) in coronary vascular resistance followed by an (increase, decrease)

Back 30

Decrease; eg. vasodilation THEN an increase

Front 31

parasympathetic activation elicits an (increase, decrease) in coronary vascular resistance

Back 31

decrease

Front 32

Most important metabolic regulator of coronary resistance

Back 32

oxygen.

Front 33

Oxygen deprivation results in an (increase, decrease) in coronary vascular resistance

Back 33

decrease (vasodilation)

Front 34

What effects do metabolites such as adenosine, prostaglandins, kinins, and potassium have on coronary resistance?

Back 34

They're released by an oxygen-deprived or ischemic myocardium and cause a DECREASE in resistance (vasodilation)

Front 35

The result of this process is that there's a range where perfusion pressure can change, but coronary flow stays the same

Back 35

autoregulation

Front 36

How is coronary flow maintained across changes in perfusion pressure?

Back 36

by adjusting the size of the arterioles/adjusting resistance

Front 37

Resistance to coronary blood flow occurs in what two locations?

Back 37

R1 : epicardial (large) artery

R2 : arteriole level (smaller)

Front 38

What are the major types of adrenergic receptors on coronary arteries?

Back 38

beta2, alpha

Front 39

In normal, non atherosclerotic vessels, the resistance at the epicardial level (R1) is (smaller, larger) than resistance at the arteriolar level (R2)

Back 39

Smaller. Usually R2 is the primary determinant of coronary flow.

Front 40

What is coronary flow reserve?

Back 40

The ability of coronary circulation to increase flow.

Mathemetically defined as the ratio of resting flow : maximal flow

Front 41

What changes are responsible for coronary flow reserve?

Back 41

Changes in arteriolar resistance (R2)

Front 42

Primary mech by which coronary blood flow (the supply) is linked to myocardial oxygen requirements (the demand).

Back 42

Changes in coronary vascular resistance

Front 43

Coronary atherosclerosis primarily affects (R1, R2).

Back 43

R1 - the epicardial arteries, as a result, atherosclerotic narrowing mainly affects resistance at the epicardial level.

Front 44

As R1 increases due to atherosclerotic blockages, what happens to R2?

Back 44

R2 decreases because the arterioles dilate to compensate for the reduced flow - to a point.

Front 45

The coronary circulation is able to compensate and keep resting/basal coronary flow constant in presence of coronary stenosis, but it occurs at the expense of ________.

Back 45

coronary reserve.

Front 46

What are the consequences of decreased coronary reserve?

Back 46

The coronary arterioles (and as a result, R2) are already as dilated as they can get, so when more is demanded of them in exertion, they're not able to accomodate --> can result in ischemia.

Front 47

What is Fractional Flow Reserve?

Back 47

Max. myocardial blood flow
in the presence of a stenosis
/
Normal maximum blood flow

Front 48

Once Fractional Flow Reserve (FFR) decreases to ____, there is risk of ischemia

Back 48

<0.8 (normally it's over 0.8)