Flashcards in Cardioplegia Bruce's Final Exam Deck (32)
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1
Chemical Cardioplegia effect on the heart?
Changes the resting membrane potential of the myocardium rendering it unexcitable
2
Intracellular
Na+ =
K+ =
Cl- =
Na+ = 12mM
K+ = 139mM
Cl- = 10 nM
3
Extracellular
Na+ =
K+ =
Cl- =
Na+ = 145 mM
K+ = 4 mM
Cl- = 150 nM
4
Cardiac muscle
(Atrial & ventricular)
resting potential mV?
- 80
5
Cardiac purkinje fiber
resting potential mV?
- 90
6
Atrioventrcular nodal cell resting potential mV?
-65
7
Sinoatrial Nodal cell resting potential mV?
- 55
8
Cardiac threshold2 is =
about 70
9
5 Constituents of Cardioplegia ?
• Hypertonic
• Buffered
• Oxygen Delivery
• Calcium
• Arresting agent
10
– [K+] > 40 =
cell membrane damage
11
Advantages of Chemical cardioplegia ?
Recovery of Function
12
Disadvantages of Cardioplegia
• Ischemic Injury
• Calcium Paradox
• Stone Heart
13
Cellular response to ischemia
Protein production
• Humeral signaling agents
• Cell membrane receptors
• Self destruct messages
• Immune Reaction and Apoptosis (programmed cell death)
14
Prevent Calcium Paradox with what ?
diltiazem or
trace calcium levels
15
What is Calcium paradox?
in vivo model of multidose cardioplegia and moderate hypothermia
16
Low levels of ATP and a calcium overload can lead what?
(Stone Heart)
17
(Stone Heart)
“massive contraction band necrosis in an irreversibly noncompliant hypertrophied heart
18
Lethal Ischemic injury occurs during ?
Re-perfusion
19
Oxygen Supply < Oxygen demand. What is the cellular response?
Programmed cell death
20
Run out of ATP (energy) > leads to what ?
-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)
21
(Q10) For every 10 degree change in temperature causes what?
metabolic rate is cut by 1/2.
22
card 23
card 23
23
Intermittent cardioplegia
has long controlled periods of ischemia
24
Continuous cardioplegia strives for what?
No Ischemia
25
Warm + Ischemia =
BAD
26
Cardioplegia temperature delivered to the heart at _____ reduces MVO2 to what _____ ?
22 degrees
97%
27
O2 delivery of blood is ?
Lowered with
low termperatures
28
Warm fibrillating heart =
Increased MVO2
29
hand held cannulas directly into individual coronary arteries is a technique necessary any time the?
Ao Root is opened
(Ao valve surgery, Ao repairs)
30
