ECG Flashcards
What does the ECG recording represent?
The movement of depolarisation through the heart.
What are the two ECG recording planes?
Transverse plane (axial, horizontal) and frontal plane (coronal).
Which leads are in the transverse plane?
Leads V1 - V6.
Which leads are in the frontal plane?
Leads I, II, III, aVR, aVL, aVF.
How many small squares are in one big square on the ECG paper?
Five small squares.
How many millivolts does one big square represent?
Five millivolts.
What is the calibration marker on the ECG paper for?
To show a 10 millivolt signal.
How many milliseconds are in one small square on the ECG paper?
40 milliseconds.
How many milliseconds are in one big square on the ECG paper?
200 milliseconds (0.2 seconds).
What is the paper speed of the ECG recording?
25 millimeters per second.
How do you calculate heart rate for a regular rhythm?
Count the squares between complexes and use the formula: 60 divided by the number of seconds the squares represent.
How do you calculate heart rate for an irregular rhythm?
Count the number of complexes in 30 large squares and multiply by 10.
What is the QRS axis?
The overall direction of the electrical signal in the frontal plane.
How do you find the most isoelectric QRS complex in the standard leads?
Look at leads I, II, III, aVF, aVR, and aVL, and find the lead with the most isoelectric QRS complex.
How do you calculate the mean frontal QRS axis?
The axis is 90 degrees from the most isoelectric QRS complex in the standard leads.
