Electrophysiology Flashcards
Essential practice and understanding of the electrical activity of the heart
Where are the limb leads placed?
- R leg and L leg
- R arm and L arm
List ways to ensure the best ECG reading.
- shave body hair
- remove oils
- attach to cables prior to placement
What are the limb leads?
I, II, III, aVR, aVL, aVF
What are the precordial leads?
V1 - V6
If you are obtaining a 12-lead ECG, how should you alter the placement of the limb leads?
Leads should be placed on the wrists and ankles.
Describe the placement of V1-V6 precordial leads.
V1:
- right of sternum
- 4th ICS
V2:
- left of sternum
- 4th ICS
V3:
- midway
- between V2 and V4
V4:
- midclavicular
- 5th ICS
V5:
- anterior axillary line
- 5th ICS
V6:
- midaxillary line
- 5th ICS
How is a posterior ECG obtained?
- V7: Between V6 and V8
- V8: Left midscapular line
- V9: Left paraspinal line
5th ICS
Define:
Augmented Unipolar Leads
It contains one true pole, and the other end is referenced against other leads.
aVR, aVF, aVL
Define:
Bipolar Leads
Each of the leads has positive and negative poles.
How much time passes in one small box of ECG paper?
.04 seconds
How many small boxes are inside one large box of ECG paper?
5
How much time passes in one large box of ECG paper?
.20 seconds
What does the P wave represent?
atrial depolarization
What does the PR interval represent?
Atrial depolarization and impulse conduction through the AV node.
What does the QRS complex represent?
ventricular depolarization
What does the J Point represent?
End of depolarization and beginning of repolarization.
What does the ST Segment represent?
early ventricular repolarization
What does the T wave represent?
ventricular repolarization
What is the first half of the T wave?
absolute refractory period
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Brainscape’s Paramedic & EMT Academy
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What is the second half of the T wave?
relative refractory period
What does the QT interval represent?
Electrical activity of one ventricular cycle.
How do you use the 6 second method for calculating the HR on ECG paper?
Count the QRS complexes in a 6 second ECG strip and multiply by 10.
What is the sequence method for determining HR on ECG paper?
Find an R wave and count with the sequence below until you reach the next R wave for each large box.
300, 150, 100, 75, 60, 50
Rhythm:
Normal sinus
- HR 60-100 bpm
- P waves present
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Sinus Tachycardia
- HR > 100 bpm
- P waves present
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Sinus Brady
- HR < 60 bpm
- P waves present
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Sinus Dysrhythmia
- HR 60-100 bpm
- P waves present
- regular rhythm
- narrow <120 ms QRS
- Slight deviation of contraction timing during inspiration.
Rhythm:
Sinus Arrest
- HR 60-100 bpm
- P waves present
- regular rhythm
- narrow <120 ms QRS
- Sudden pause in rhythm to indicate cessation of sinus contraction.
Rhythm:
Atrial Flutter
- HR 60-100 bpm
- P waves present; 3:1 conduction
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Atrial Fibrillation
- Irregular HR/QRS.
- No discernible P waves.
- narrow <120 ms QRS
Rhythm:
Supraventricular Tachycardia
- HR > 150 bpm
- P waves present (sometimes blends with T wave)
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Hint: Complex
Premature Atrial Complex
- A complex within another rhythm
- P waves present
- narrow <120 ms
PAC
Rhythm:
Junctional Escape Rhythm
- HR 40-60 bpm
- P waves absent
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Accelerated Junctional
- HR 60-100 bpm
- P waves absent
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Junctional Tachycardia
- HR >100 bpm
- P waves absent
- regular rhythm
- narrow <120 ms QRS
Rhythm:
Hint: Complex
Premature Junctional Complex
- complex within a rhythm
- P waves absent
- QRS <120 ms
Type of heart block.
First degree heart block
- PR Interval >200 ms
- QRS <120 ms
- regular rhythm
- P waves present
Type of heart block.
Second degree type I
- QRS <120 ms
- HR 60-100 bpm
- P waves are delayed a little longer each beat, until an entire complex is dropped.
- regular rhythm
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Type of heart block.
Second degree type II
- PR interval is constant; several impulses do not contract.
- QRS <120 ms
- HR 60-100 bpm
- regular or irregular rhythm
Type of Heart block.
Third degree
- Impulses reaching the AV node are not conducted to the ventricles; ventricles become their own pacemaker.
- ventricular rate <60 bpm
- SA rate 60-100 bpm
- QRS >120 ms (but can be <120 ms)
Rhythm:
Idioventricular
- HR 20-40 bpm
- P waves absent
- regular rhythm
- wide >120 ms QRS
Rhythm:
Ventricular Tachycardia
- HR >100 bpm
- P waves absent
- regular rhythm
- wide >120 ms QRS
Rhythm:
Hint: Complex
Premature Ventricular Complex
- Complex within a rhythm.
- P wave absent
- QRS >120 ms
Rhythm:
asystole
No electrical activity is present.
Rhythm:
Ventricular Fibrillation
- The heart is quivering, and there is no contraction of the heart.
- No P waves or QRS.
- chaotic baseline
Rhythm:
Ventricular Pacemaker
- wide QRS
- Pacer spikes present before ventricular contraction.
Rhythm:
AV Sequential Pacemaker
- Pacer spikes before P waves and ventricular contraction.
Name the axis deviation.
I is up
aVF is up
normal axis
Name the axis deviation.
I is up
aVF is down
left axis
Name the axis deviation.
I is down
aVF is up
right axis
What is the Axis Deviation?
I is down
aVF is down
extreme right
What type of bundle branch block is present?
When you have a QRS >120 ms and a terminal R wave in V1.
right bundle branch block
What type of bundle branch block do you have?
When you have a QRS >120 ms and terminal S wave in V1.
left bundle branch block
How do you determine right ventricular Hypertrophy in a 12-lead?
- large R wave in V1
- R wave in lead aVR >5 mm
How do you determine left ventricular Hypertrophy in a 12-Lead?
- tallest R wave in V5/V6 + deepest S wave in V1/V2 >35 mm
- R wave in lead aVL >11 mm
Fill in the blank.
Q waves are pathologic if they are in ___ small square on an ECG paper.
1
40 ms
List the progression of ischemia to infarction.
- Ischemia begins with an inverted T wave and leads to elevated ST segment.
- Injury begins when a Q wave starts forming.
- Infarction occurs after the ST segment reaches its maximum elevation and returns to baseline; a pathologic Q wave remains.
What are contiguous leads?
Leads that view similar areas of the heart.
Eg. V1, V2 : II, III, aVF
Fill in the blank.
About ___% of people having an Inferior MI also have ______ ventricular involvement.
40, right
Interpret what’s being shown in this picture.
Inferior STEMI
- Elevation in II, III, aVF.
- Eeciprocal changes in I and aVL.
- Elevation is >1 mm in two contiguous leads.