文档介绍：12 Lead ECG
1998
1
Objectives
Fundamental review
Importance of the EMS 12 lead
Identify the 3 “I’s”
Identify the presence of the ST segment elevation, depression and pathologic Q wave on 12 lead ECG.
1998
2
Fundamentals
SA node:
Impulse formation is initiated
Dominant pacemaker of the heart.
55% population supplied by RCA, 45% by LCA
1998
3
Fundamentals
Internodal Pathways:
Carry the impulse from the SA node to the AV node
1998
4
Fundamentals
AV Junction:
This tissue acts as an escape pacemaker ...if the SA and Atrial tissues fail.
The inherent rate of the AV junction is 45-55 beats per minute.
1998
5
Fundamentals
AV node:
Protects the ventricles from:
run away atrial rates and delays conduction allowing for ventricular filling time.
Heavy vagal(parasympathetic) innervation .
Receives oxygenated blood from the RCA
1998
6
Fundamentals
Bundle Branches
Right and Left bundle branches..
Escape pacemakers are slow (20-30 bpm) and unreliable.
The bundle branches receive virtually all their oxygenated blood from the LCA.
1998
7
Fundamentals
Purkinje fibers:
The bundles divides numerous times into the Purkinje fibers.
Final pathways of conduction to the ventricles
1998
8
Patient Position
Patient positioning important:
Preference to hospitals = flat
Different positions cause 12 lead changes
Include the patient position in your report
Note patients position on the 12 lead also
1998
9
Indications for a 12 Lead
1. Chest Pain:
Unrelieved by Nitroglycerin
Lasting greater than 30 minutes.
2. ST Segment elevation
Greater than 1mm in 2 or more adjacent leads.
1998
10