ECG Flashcards
What part of the wave form represents atrial depolarization?
P Wave
What part of the wave form represents ventricular depolarization?
QRS Complex
What is a Q wave?
Negative deflection following the P wave
What is an R wave?
Positive deflection following a Q wave
What is an S wave?
1st negative deflection following the R wave
What is special about the P wave in the V1 lead?
It will typically be negative
True or false: Not everyone has a QRS?
True
What is a Q wave called that is <0.04sec?
Physiologic
What is a Q wave called that is >0.04sec?
Pathologic
A QRS complex is wide if it is greater than _____ in length.
0.12 seconds
A QRS complex is narrow if it is shorter than _____ in length.
0.10 seconds
What is a sign of something wrong in the T wave?
If it is lumpy or knotched
What does the T wave represent?
Ventricular Repolarization
What is a span of time following a complex?
Segment
What portion of the ECG is represented at the end of the QRS complex to the beginning of the T wave?
ST segment
What is the period of recovery that cells need after being discharged before they are able to respond to a stimulus?
Refractoriness
What area is represented from onset of QRS complex to approximate peak of T wave when cells cannot be stimulated to conduct an electrical impulse, no matter how strong the stimulus?
Absolute Refractory Period
What PR interval length is abnormal?
> 0.20sec or 200ms
What QT interval length is abnormal?
> 0.40sec or 400ms
A Q wave is pathologic if it is…
More than 0.04sec in length
A Q wave is physiologic if it is…
Less than 0.04sec in length
The onset of the QRS complex to the peak of the T wave is called the…
Absolute Refractory Period
The downslope of the T wave is called the…
Relative Refractory Period
The end of the T wave marks the beginning of the…
Supernormal Period
One small square on an ECG represents…
1mm voltage and 0.04sec time
One block of 5-squares on the ECG represents…
5mm voltage and 0.2sec time
Why is Lead II the preferred lead to look at for heart rhythm and rate?
It starts at the bottom left limb and travels through the heart to the upper right shoulder, showing the complete conduction system of the heart.
What does the PR Segment represent?
Electrical depolarizing from the AV node through the bundle of HIS to the Purkinje fibers.
Where does the PR Segment begin and end on the ECG?
The horizontal line between the end of the P wave and the beginning of the QRS complex.
Where does the TP Segment begin and end on the ECG?
The end of the T wave and the beginning of the following P wave.
Where does the ST Segment begin and end on the ECG?
The end of teh QRS complex and the beginning of the T wave.
Where does the QT interval begin and end on teh ECG?
The beginning of the QRS complex to the end of the T-wave.
Where does the PR interval begin and end on the ECG?
The beginning of the P wave to the beginning of the QRS complex; also called the PQ interval.
What does a long (>0.2sec) PR interval represent?
The electrical impulse was delayed as it passed through the atria or AV node.
What is the intrinsic rate of the SA node?
60-100
What is the intrinsic rate of the AV node (junction all rhythm)?
40-60
What is the intrinsic rate of the ventricles/purkinjes?
20-40
What is the difference between a PJC and a PAC? How are they alike?
PAC- P wave is upright
PJC- P wave is inverted or nonexistent
Both come early
What is the same as a PJC, but occurs late?
Junctional Escape Beat
Junctional Rhythm
40-60, regular
- if visible, P wave will be inverted in leads II, III, and aVF
1st Degree AV Block
- Atrial & Ventricular rates= regular, depends on underlying rhythm
- Regular, normal size/shape of P’s
- PR delay >0.20, QRS narrow
2nd Degree AV Block, Type 1
- Atrial rate is greater than ventricular
- Atrial regular/Ventricular irregular
- P waves normal but not all followed by QRS
- PR interval delayed and gets longer until P is not followed by QRS
2nd Degree AV Block, Type II
- Atrial rate greater than ventricular rate, ventricular rate is slow
- Atrial regular/ Ventricular irregular
- P waves normal but not all followed by QRS
- PR interval normal or slight delay
- QRS wide or non present at times
3rd Degree AV Block
- Atrial rate > Ventricular rate
- Atrial regular, ventricular regular, no relationship between them
- P waves normal
- No true PR interval
- QRS narrow or wide
Which lead is best for viewing bundle branch blocks?
V1
