EKG Ch. 3 Flashcards
Lead Review (20 cards)
What does a 12-lead EKG provide once interpreted correctly?
A wealth of information regarding heart conditions such as heart block, ischemia, and infarction.
This is achieved by measuring electrical currents from the heart through electrodes placed at consistent distances.
What are the two types of leads in a 12-lead EKG?
- Limb leads
- Chest leads
What are the two types of limb leads?
- Bipolar leads (I, II, III)
- Unipolar augmented leads (aVR, aVL, aVF)
What are the standard bipolar limb leads?
- Lead I
- Lead II
- Lead III
What is Einthoven’s law?
The magnitude of the deflection of lead II is equal to the sum of the deflections of leads I and III.
This is represented by the equation I + III = II.
What is the purpose of the right-leg electrode in limb lead placement?
Functions as an electrical grounding system.
What does lead I measure?
The electrical difference between the left-arm (LA) and right-arm (RA) electrodes.
What does lead II measure?
The electrical difference between the left-leg (LL) and right-arm (RA) electrodes.
What does lead III measure?
The electrical difference between the left-leg (LL) and left-arm (LA) electrodes.
What is the significance of the term ‘augmented’ in unipolar augmented leads?
These leads record voltages at one location relative to zero and are augmented over the actual voltage from each extremity.
What are the three unipolar augmented leads?
- aVR
- aVL
- aVF
What does the equation aVR + aVL + aVF equal?
0
What is the placement for lead V1?
Right fourth intercostal space.
What is the placement for lead V4?
Left fifth intercostal space in the midclavicular line.
What is R wave progression?
The normal changes in the QRS complex height as you move across the chest leads.
What is poor R wave progression indicative of?
- Right or left ventricular hypertrophy
- Left bundle branch block
- Lead misplacement
- Infarction
What leads are considered lateral leads?
- I
- aVL
- V5
- V6
What leads are considered inferior leads?
- II
- III
- aVF
Which leads are referred to as anteroseptal leads?
V1 and V2
Which clinical conditions are associated with poor R wave progression?
- Anterior and/or lateral wall myocardial infarction
- Left ventricular hypertrophy
- Left bundle branch block
- Fascicular block
- Lead misplacement
