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Anatomy
ECG Electrodes
ECG Waveform
The 12 lead ECG
How does the heart work
AV node activated by Atrial depolarizationSends signal through His-purkinje bundleGet depolarization of SEPTUM
Left and Right BUNDLES transmit signal to Left and Right VENTRICLESNet “Vector” towards the LVShould be narrow (<120msec) if bundles working properlyThen have REPOLARIZATION = Twave
The appearance of this electrical activity depends on which lead you are using to look at it
Review of waveforms
How to Look at an ECG• Rate: Is the heart rate too fast or slow?• Rhythm: Sinus rhythm or not?• Axis: Where does the majority of
electrical activity point?• P wave: How big are the atria?• PR interval: How healthy is the AV node?• QRS wave: Is there abnormal conduction
or a ventricular source?• QT: Long is bad• Ischemia and hypertrophy
ECG PaperCan Determine Heart Rate
Rule: 300, 150, 100, 75, 60, 50 counting over for each big sqaure
What is the heart rate?
Answer = 75 per min
Rhythm : Is there a p wave? = Sinus
Is it followed by a QRS?
Is the rhythm regular or irregular?
Reasons to have an irregular rhythm
• Irregular pacemaker– Multifocal atrial
rhythm
– Atrial fibrillation
– Atrial fib/flutter
• Ectopic beats– PVC
– PAC
– PJC
• Irregular conduction– AV node block
• 1st degree:– PR interval > 200 msec
• 2nd degree:– Type 1: Wenkebach
– Type 2: dropped beat
• 3rd degree:– p waves marching
independent to QRS
Examples of Rhythms
Multifocal Atrial Rhythm
AFIB
Atrial Flutter
AFIB
V TACH
Example of a PVC
Telling the Axis from the leads
The axis wheel
The P wave
The QRS
QRS < 120 msec
QRS > 120 msecRabbit ears in V1 & V2
Wide S wave in V5 & V6
R axis deviation
QRS > 120 msecDeep slurred S wave in V1
Wide R wave in V6, I & avL
L axis deviation
Ishcemia vs Acute Infarct
Example of Ischemia
Examples of Infarctions
Review• Rate: Is the heart rate too fast or slow?• Rhythm: Sinus rhythm or not?• Axis: Where does the majority of
electrical activity point?• P wave: How big are the atria?• PR interval: How healthy is the AV node?• QRS wave: Is there abnormal conduction
or a ventricular source?• QT: Long is bad• Ischemia and hypertrophy
Describe this ECG
Describe this Strip