Where is impulse generated?
Sinoatrial (SA) node - right atrium near Sup. VC
Where is the AV node?
Posterior septal wall of right atrium near tricuspid valve
What is the order of conduction?
- SA node
- AV node
- AV (His) bundle
- Right/Left bundle branches
- Purkinje fiber network
What are the Bipolar limb leads?
- I - right arm to left arm
- II - right arm to left leg
- III - left arm to left leg
What are the Augmented unipolar limb leads?
- aVR - V to right arm
- aVL - V to left arm
- aVF - V to left leg
What is the triangle made up by the bipolar limb leads?
What is responsible for the P wave?
Atrial muscle depolarization
What is responsible for the QRS complex?
- Ventricular depolarization
- also, atrial repolarization
Measure of conduction through the AV node
Measure of time where all myocardium in Phase 2 plateau state
What is responsible for the T wave?
Repolarization of the ventricles
What is responsible for the U wave?
Repolarization of myocardial "M" cells
What are the leads of a 12 lead ECG?
- Bipolar (I, II, III)
- Augmented unipolar (aVR, aVL, aVF)
- Precordial leads (V1-V6)
3. Sinus rhythm
- 1. >100 bpm
- 2. <60 bpm
- 3. impulse originates at SA node
Define Mean QRS Vector
How to determine?
- Sum of all vectors in ventricles during depolarization
- Closest to most positive lead
- If both I and aVF have positive QRS, then probably normal