ILE VIII- AFib
Describe cardiac action potentials.
0. Opening of Na channels (Na goes from outside to inside)
1. Notch phase; opening of K channels (K goes from inside to outside)
2. Opening of Ca channels (let Ca into cells)
3. Closing of Ca channels; new K channels open (K starts flowing back
in)
What is high and low inside the cell at rest?
K high inside
Na high outside
What is responsible for reestablishing resting potential?
Na/K/ATPase pump in fast tissue (3 Na out/2 K in)
What is slow tissue?
Nodal tissue
What is the pacemaker?
SA Node
What are the two pumps in cardiac tissue?
Na/K/ATPase
Na/Ca exchanger
Where are fast Na channels found?
Phase 0 because nodal tissue requires calcium for initial depolarization
Where are calcium L channels found?
Phase 2 in fast tissue (Lets calcium in)
, Where are calcium T channels found?
Phase 4 (Threshold in slow/nodal tissue)
Where is the inward rectifier K channel?
Phase 4 - brings K in to restore resting potential
Where is the transient outward K channel?
Phase 1 - Na just shot in and is forcing K out
Where is the delayed rectifier K channel?
Phase 3- new K channels open to allow K to flow back into the heart
What does the P wave reflect?
Atrial contraction
What does the QRS complex reflect?
Ventricular contraction
What does the T wave reflect?
Repolarization
What are the 3 mechanisms of arrhythmias?
1. Increased Automaticity
2. Triggered Activity
3. Re-entry
Describe Increased Automaticity
Describe cardiac action potentials.
0. Opening of Na channels (Na goes from outside to inside)
1. Notch phase; opening of K channels (K goes from inside to outside)
2. Opening of Ca channels (let Ca into cells)
3. Closing of Ca channels; new K channels open (K starts flowing back
in)
What is high and low inside the cell at rest?
K high inside
Na high outside
What is responsible for reestablishing resting potential?
Na/K/ATPase pump in fast tissue (3 Na out/2 K in)
What is slow tissue?
Nodal tissue
What is the pacemaker?
SA Node
What are the two pumps in cardiac tissue?
Na/K/ATPase
Na/Ca exchanger
Where are fast Na channels found?
Phase 0 because nodal tissue requires calcium for initial depolarization
Where are calcium L channels found?
Phase 2 in fast tissue (Lets calcium in)
, Where are calcium T channels found?
Phase 4 (Threshold in slow/nodal tissue)
Where is the inward rectifier K channel?
Phase 4 - brings K in to restore resting potential
Where is the transient outward K channel?
Phase 1 - Na just shot in and is forcing K out
Where is the delayed rectifier K channel?
Phase 3- new K channels open to allow K to flow back into the heart
What does the P wave reflect?
Atrial contraction
What does the QRS complex reflect?
Ventricular contraction
What does the T wave reflect?
Repolarization
What are the 3 mechanisms of arrhythmias?
1. Increased Automaticity
2. Triggered Activity
3. Re-entry
Describe Increased Automaticity
