Cardioplegia Bruce's Final Exam

Question 1

Chemical Cardioplegia effect on the heart?

Answer 1

Changes the resting membrane potential of the myocardium rendering it unexcitable

Question 2

Intracellular
Na+ =
K+ =
Cl- =

Answer 2

Na+ =  12mM
K+   =  139mM
Cl-   = 10 nM

Question 3

Extracellular
Na+ =
K+ =
Cl- =

Answer 3

Na+ =  145 mM
K+   =  4 mM
Cl-   = 150 nM

Question 4

Cardiac muscle
(Atrial & ventricular)
resting potential mV?

Answer 4

• 80

Question 5

Cardiac purkinje fiber

resting potential mV?

Answer 5

• 90

Question 6

Atrioventrcular nodal cell resting potential mV?

Answer 6

-65

Question 7

Sinoatrial Nodal cell resting potential mV?

Answer 7

• 55

Question 8

Cardiac threshold2 is =

Answer 8

about 70

Question 9

5 Constituents of Cardioplegia ?

Answer 9

• Hypertonic
• Buffered
• Oxygen Delivery
• Calcium
• Arresting agent

Question 10

– [K+] > 40 =

Answer 10

cell membrane damage

Question 11

Advantages of Chemical cardioplegia ?

Answer 11

Recovery of Function

Question 12

Disadvantages of Cardioplegia

Answer 12

• Ischemic Injury
• Calcium Paradox
• Stone Heart

Question 13

Cellular response to ischemia

Answer 13

Protein production 
• Humeral signaling agents 
• Cell membrane receptors 
• Self destruct messages 
• Immune Reaction and Apoptosis (programmed cell death)

Question 14

Prevent Calcium Paradox with what ?

Answer 14

diltiazem or

trace calcium levels

Question 15

What is Calcium paradox?

Answer 15

in vivo model of multidose cardioplegia and moderate hypothermia

Question 16

Low levels of ATP and a calcium overload can lead what?

Answer 16

(Stone Heart)

Question 17

(Stone Heart)

Answer 17

“massive contraction band necrosis in an irreversibly noncompliant hypertrophied heart

Question 18

Lethal Ischemic injury occurs during ?

Answer 18

Re-perfusion

Question 19

Oxygen Supply < Oxygen demand. What is the cellular response?

Answer 19

Programmed cell death

Question 20

Run out of ATP (energy) > leads to what ?

Answer 20

-Calcium leaks out of the SR
-Calcium leaks out of the cell
-Reperfusion with Ca leads
to massive Ca release
- Absence of ATP results in
tetanic contracture (rigor
mortis)

Question 21

(Q10) For every 10 degree change in temperature causes what?

Answer 21

metabolic rate is cut by 1/2.

Question 22

card 23

Answer 22

card 23

Question 23

Intermittent cardioplegia

Answer 23

has long controlled periods of ischemia

Question 24

Continuous cardioplegia strives for what?

Answer 24

No Ischemia

Question 25

Warm + Ischemia =

Answer 25

BAD

Question 26

Cardioplegia temperature delivered to the heart at _____ reduces MVO2 to what _____ ?

Answer 26

22 degrees

97%

Question 27

O2 delivery of blood is ?

Answer 27

Lowered with

low termperatures

Question 28

Warm fibrillating heart =

Answer 28

Increased MVO2

Question 29

hand held cannulas directly into individual coronary arteries is a technique necessary any time the?

Answer 29

Ao Root is opened

Ao valve surgery, Ao repairs

Question 30

For pre-operative ischemia what protocol should be used?

Answer 30

• Warm induction
• Initiation: Reperfusate bag + 12.5 ml K+
  Q = 150 ml 3min A/R
• Follow with 100 ml cold multidose

Question 31

Reperfusate solution contains what?

Answer 31

Substrates:
- Aspartate
- Glutamate
these amino acids replenish key Krebs-cycle depleted during ischemia by enhancing aerobic metabolism and reparative processes.

Question 32

Interruption of ATP dependant mechanisms cases what 4 things ?

Answer 32

-Na/K pump malfunction
-SR stores of Ca to leak out
-Contractre band forms that
cannot be released
-compare to rigor mortis