1. cardiac SA Node
conduc- tion
system
Intra-Atrial Pathways
AV Node
Bundle of HIS
Bundle Branches
2. Sinoatrial Purkinje Fibers
Node (SA
Node)
Normal pacemaker of heart
Initiates an impulse
3. Intra-Atrial Intrinsic rate of 60 - 100 BPM
and Nodal
Pathways
Located in atrial tissue between SA and AV nodes
Conducts impulse from SA node - atrial musculature -
4. Atrioventricula AV node Anterior, middle and posterior tracts
r Node (AV
Node)
Delays impulse from atria
Allows for ventricular filling
Protective mechanism against rapid supraventricular impulses
5. Junctional Tissue Tissue in lower AV node
Back up pacemaker
Intrinsic rate of 40 - 60 BPM
6. Bundle of His and Bundle of His connects AV node to right and left bundle branches
Right/Left Bundle Right bundle carries impulse to right ventricle; left bundle carries impulse
to left
Branches sue
7. Ventricular Tis-
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ventricle
Back up pacemaker
Intrinsic rate of 20 - 40
BPM
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8. Purkinje System Distal to the bundle branches
Rapidly conducts impulses to ventricular sub-endocardial layers
9. Normal PR
Inter- val 0.12 - 0.20 seconds
measurement
10. Normal QRS 0.04 - < 0.12 seconds
Complex
mea-
surement
11. Normal QT < 0.44 seconds
Inter- val
measurement
12. Normal ST Normally isoelectric
seg- ment
measure-
ment
13. Ischemia > 0.5mm below baseline (all leads)
mea-
surement
14. Infarct > 1mm above baseline in limb leads; > 2mm above baseline in V
measure- leads
ments
15. normal The SA node (normal pacemaker) of the heart is in
sinus
rhythm control Regular rhythm
PR normal (0.12 - 0.20
sec) QRS normal (0.04 - <
0.12 sec) Rate is 60 - 100
BPM
16. Sinus
Tachycar- dia
Same characteristics as sinus
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