What are the four anterior leads?
V1-V4
What are the four lateral leads?
I
aVL
V5, V6
What are the three inferior leads?
II, III
aVF
What does one “small box” represent horizontally? Vertically?
- Horizontal = 0.04 seconds in duration
- Vertical = 1 mm (0.1 mV) in amplitude
What is the NORMAL duration for a P wave? NORMAL amplitude?
P wave
- Duration: 0.06-0.10 seconds
- Amplitude: 0.5-2.5 mm high
When does the PR interval start and end?
- Start: P wave
- End: beginning of QRS complex
What is the NORMAL duration for a PR interval?
PR interval
- Duration: 0.12-0.20 seconds
What deflection correlates with each part of the QRS complex?
- Q wave = first negative deflection
- R wave = any positive deflection following Q wave/PR segment
- S wave = any negative deflection following R wave
What is the NORMAL duration for a QRS complex?
QRS complex
- Duration: 0.06-0.12 seconds
What is the ST segment? What is the J point?
- ST segment: flat line that follows QRS complex
- J point: where QRS complex meets ST segment
When does the QT interval start and end, and what part of the cardiac cycle does it represent?
Time of ventricular depolarization and repolarization
- Start: beginning of QRS complex
- End: end of T wave
What is the NORMAL duration for a QT interval? What is it dependent on?
Duration: 0.36-0.44 seconds
- Dependent on HR (as HR decreases, QT interval increases = inverse relationship)
What are the NORMAL values for the following:
- Rate?
- Rhythm?
- P wave (2)?
- QRS complex?
- PR interval?
- QT interval?
- Rate: 60-100 bpm
- Rhythm: regular
- P wave: 0.06-0.10 seconds, 0.5-2.5 mm
- QRS complex: 0.0.6-0.12 seconds
- PR interval: 0.12-0.20 seconds
- QT interval: 0.36-0.44 seconds
What does a NORMAL P wave look like (2)? NORMAL QRS complex (2)? NORMAL T wave (2)?
- P wave = upright, rounded
- QRS complex = upright, narrow
- T wave = upright, slightly asymmetrical
What would the amplitude be for a “tall, rounded or peaked” P wave? What does this indicate?
Amplitude is greater than 2.5 mm
- RAE = “P pulmonale”
What would the duration be for a “wide, notched or biphasic” P wave? What does this indicate?
Duration is greater than 0.10 seconds
- LAE = “P mitrale”
What are the five steps of EKG analysis?
- Determine rhythm (regularity)
- Calculate rate
- Evaluate P wave
- Evaluate QRS complex
- Evaluate PR interval
What type of rhythm is the Large-Box Estimate LESS accurate with? What is the number order (300, …), and where do you start/end?
Less accurate with irregular rhythms
- 300, 150, 100, 75, 60, 50
- Start at first R wave on/near a bolded line - next bold line is 300…
- End at next R wave on/near a bolded line (if between, use range)
What type of rhythm can the 1500 Method NOT be used with? How does this method work?
CANNOT be used with irregular rhythms
- Count small boxes between two R waves and divide by 1500
What type of rate might cause the P wave to be buried in the T wave, and what will the T wave likely look like?
Rapid rates can have P wave hidden in T wave
- T wave will be peaked, notched or larger than normal
What pathology might cause a wide/bizarre QRS complex?
BBB (left or right)
