PPT 12: angina

Question 1

What are the two functions of the venous system?

Answer 1

1. Conduct blood back to the heart
2. Reservoir for blood volume (contain 70% of total blood volume, 20-30% in splanchnic bed)

Question 2

What is the benefit of the venous system having larger volume of blood compared to arterial?

Answer 2

Maintains filling of heart despite significant variation in blood volume

Question 3

What are effects from increased venous tone (venous constriction)

Answer 3

increases all the following:
venous return to right ventricle → EDV (end diastolic volume) → stretch of cardiac myocytes → force of contraction (Starling’s law) → stroke volume → cardiac output → blood pressure

Question 4

what are the effects of decreased venous tone (venodilation)

Answer 4

increased capacitance

decreased all the following:
venous return to right ventricle → EDV (end diastolic volume) → stretch of cardiac myocyte → force of contraction (starling’s law) → stroke volume → cardiac output → BP

Question 5

What is angina caused by

Answer 5

accumulation of metabolites due to myocardia ischemia

Question 6

What drug is given for immediate relief of angina?

Answer 6

nitroglycerin

Question 7

What drugs are good for angina prophylaxis?

Answer 7

calcium channel blockers and beta blockers

Question 8

Which type of angina is classic angina

Answer 8

“angina of effort”
O2 requirement increases with activity, but coronary blood flow not enough, leads to O2 debt and ischemia with toxic metabolites

Question 9

what type of angina is also known as Prinzmetal angina or vasospastic?

Answer 9

Variant angina
O2 delivery decreased due to coronary vasospasm

Question 10

What type of angina is also known as “angina at rest”?

Answer 10

Unstable angina
microvascular disease s/t small patelet clots and atherosclerotic plaque

Question 11

Which type of angina is an emergency?

Answer 11

unstable angina

Question 12

Which type of angina is most rare?

Answer 12

variant

Question 13

What is treatment of classic angina?

Answer 13

reduction of demand through beta blockers, calcium channel blockers

Question 14

what is treatment of variant angina?

Answer 14

primarily calcium channel blockers to prevent , vasodilators/nitrates

Question 15

Coronary blood flow is _______ related to perfusion pressure, _______ related to duration of diastole, and ________ related to coronary vascular bed resistance

Answer 15

directly, directly, indirectly

Question 16

Which blood vessels have the best response to nitrates and nitrites?

Answer 16

large veins

Question 17

What is the mechanism of action of nitroglycerin?

Answer 17

NO release in vascular smooth muscle

Question 18

What is the ADME of nitroglycerin

Answer 18

A: low bioavailability (10-20%), subligual or IV route
M: high 1st pass metabolism (nitrate reductase in liver)
E: kidneys

Question 19

How does NO lead to vasodilation?

Answer 19

NO activates guanylyl cyclase, which converts GTP to cGMP. cGMP dephosphorylates Myosin-LC leading to relaxation

Question 20

What Nitrate/Nitrite was used, and abused, by inhaling to reduce BP (and short high)

Answer 20

Amyl Nitrite (“poppers”)

Question 21

What are the good effects from Nitrates and Nitrites?

Answer 21

Increased venous capacitance
decreased ventricular preload
decreased heart size
decreased cardiac output

Question 22

What are the bad effects of nitrates and nitrites?

Answer 22

Headache (most common), orthostatic hypotension, syncope, reflex tachycardia, hemoglobin interactions (methehemoglobin = low affinity for oxygen)

Question 23

What are the 3 types of vascular tone?

Answer 23

1. Arteriolar tone
   
   • Arteries, arterioles
   • Precapillary sphincters
2. Capillary tone
3. Venous tone

Question 24

Describe how Ca++ contributes to blood vessel contraction

Answer 24

• Ca++ binds to calmodulin (protein) → activates MLCK → MLC-P interacts with actin to contract
• cAMP inhibits MLCK

Question 25

What are the different drugs that induce relaxation of vascular tone?

Answer 25

Ca++ channel blockers (prevent contraction)
K+ channel blockers (prevent depolarization)
B2 agonists (increase cAMP)
Nitrates (increase cGMP)

Question 26

How do Ca++ channel blockers treat angina?

Answer 26

• L-type channel most dominant in cardiac and smooth muscle
• Drug binds to depolarized membranes
• Decreased opening frequency with drug binding
• relaxation and reduced BP in smooth muscle
• Heart: ↓ contractility, ↓ SA node pacemaker rate, ↓ AV node conduction velocity

Question 27

How are Beta Blockers used for angina treatment?

Answer 27

Not vasodilators - decrease oxygen demand
↓ HR
↓ BP
↓ Contractility
- more B2 receptors in micro-arteries → dilation

Question 28

How do pFOX inhibitors treat angina?

Answer 28

• Decreased oxygen requirement in cardiac metabolism
• ↓ FOX, ↑ glucose utilization (more efficient)

Question 29

What are the contraindicated vasodilators for angina? Why are they contraindicated?

Answer 29

1. Hydralazine, Minoxidil - May increase angina (increased SNS output)
2. Sodium Nitroprusside - Hypertensive emergencies; High toxicity – better agents for angina (May be useful for vasospastic angina)
3. Fenoldepam - Reflex tachycardia

Question 30

What risk factors contribute to angina symptoms?

Answer 30

• Smoking
• Hypertension
• Hyperlipidemia

Question 31

What are the non-pharmaceutical interventions for angina?

Answer 31

• Surgical revascularization (CABG)
• Cardiac catheter
• Stent