Week 2 Flashcards
What does a technically acceptable tracing include?
1) Steady baseline, no distortions from artifacts (I.e. tremors)
2) Print quality - each deflection can be seen clearly.
3) Standardization - visible and set to normal unless noted otherwise.
4) Patient information 100% correct.
5) All correct settings used.
Quality assurance - How do we know the ECG is hooked up correctly?
1) The p and t waves are positive in lead 1.
2) The P and T waves are positive in lead 2.
3) The deflections in lead 2 are the tallest of all the bipolar leads ( einthoven’s law)
4) The P and T waves are negative in a AVR.
5) There is a progression in the R waves from V1-V5. (* at least in V1- V4)
What are artifacts?
And what does it look like on the ECG?
They are non cardiac voltages or interferences.
A distortion in the waves and baseline.
Why do we not want artifacts?
Because they may create problems when the various measurements and readings are made.
What are the two types of artifacts?
Electrical - caused by alternating current (AC)
Physical - caused by the patient or sensor/patient cable.
What does electrical interference look like on the reading?
Consistent and regular pattern of “ saw - tooth,” notching or small - straight-spiked deflections all along the baseline, there will be 60 notches/second.
What causes electrical interference?
An outside electric or magnetic source.
Usually caused by leakage of alternating electric current from neighboring appliances or from wiring, power chords, Or even the ECG machine.
Broken cable wire or poor quality electrolyte may also contribute to AC.
How can we make sure electrical interference does not occur?
Ensure the ECG is grounded using a three-pronged plug.
Ensure the lead wires follow the body contour.
Direct machine power cord or extension cord away from the patient.
Disconnect plugs on all other electrical equipment in the room, especially from the same outlet.
Keep patient bed away from walls that may contain electrical wiring.
Use the battery operation function if possible.
What causes physical interference?
Somatic or muscle tremor appears as a fuzzy, irregular baseline. usually uneven in space and unequal in height. This type of interference may result from voluntary or involuntary patient movement.
What can we do to help patients with physical interferences?
For adults, we can try to gain the patient’s confidence.
For children we can try to make friends. Maybe offer them a sticker if they keep still.
For tiny babies soothing and to keep them warm.
Ensure the room is pleasant and warm. Free from medical devices and unnecessary supplies, equipment, or material.
What can we do for patients with a nervous system disorder such as parkinson’s disease to help with interference?
Place the patient’s hands under their butt or support with a pillow.
May need to use a filter
What is a positive deflection?
Any wave above the isoelectric line is a positive.
What is a negative deflection?
Any wave below the isoelectric line is negative.
What is an isoelectric line?
Anything that’s a flat straight line like the baseline.
Depolarization
Activation of cells.
Repolarization
Resting or return to resting state.
The isoelectric line
Following the Twave ( or U wave if present), the heart returns to its resting or polarized state.
There is no electrical wave at this time, and a straight horizontal line will be recorded called the baseline or isoelectric zero voltage line.
What causes the P wave
The impulse initiated by the SA node causes the left and right atria to contract.
The first event to occur in the normal cardiac cycle is?
P wave
What is the duration of the P wave?
0.06~0.11 seconds
What is the P wave?
It is the depolarization of the atria.
* atrial contraction
What is the PR interval?
It is the time lapsed between the beginning of atrial and ventricular depolization.
The time it takes for the impulse to get from the atria to the ventricles.
What does the QRS complex represent?
It represents the depolarization of the ventricles.
What complex results in ventricular contraction?
QRS complex
What does the T wave represent?
Ventricular repolarization or electrical recovery.
The cells recharge themselves in preparation for the next impulse.
What is the U wave?
It’s sometimes follows the T wave. its significance is unknown.
What happens in a U wave?
U waves become higher when the heart is enlarged or blood potassium (K) level drops below normal.
Hypokalemia
Low serum K level
Where is the rhythm strip and what is it used for?
The rhythm strip runs along the bottom of the ECG tracing.
It is used to measure the distance between beats.
