Cardiopulmonary: Lecture 4 - ECG Flashcards
What are the 4 questions to ask when interpreting an ECG
Speed?
QRS Width?
P Wave?
Regular or Irregular?
How long is a normal ECG strip?
6 seconds
What is atrial kick?
Normal contraction of atria to increase pressure gradient and send blood to ventricals through mitral valve
What does the P wave represent?
Depolarization of atria
What does the PR interval represent?
Duration of time for electricity to go from SA to AV node (Atria to ventricals)
What does the QRS complex represent
R and L ventricular depolarization
What does the T wave represent?
Ventricular repolarization
What does the QT interval represent
Time between ventricular start of depolarization and end of repolarization
If an ECG is reading with an abnormally low voltage, does this mean a problem is likely?
Yes
What is the isoelectric line?
The x=(0) in an ECG
Monitoring a Q wave is important because it can tell you….
If there was a recent MI
The normal rythmicity of the SA node is…
60-100bpm
The normal rythmicity of the AV node, the AV junction, and the Bundle of His is…
40-60bpm
What is the normal rhythmicity of the purkinje networks?
20-40
The rate of an arythmia can tell you what?
Where its coming from based on the autorythmicity of the different heart cells
An inverted T wave could potentially indicate what 2 problems?
Myocardial ischemia or infarction
An ST segment depressed by 2 boxes could mean what
Myocardial ischemia
An ST segment elevated by 2 boxes could mean what
Myocardial infarction
What is the risk associated with an ST segment being too long?
RIsk of serious ventricular arrythmias due to slow repolarization time
How many leads does a typical ECG have?
12
Limb Lead 1 goes from where to where?
From R to L
Limb Lead 2 goes from where to where?
From upper right to lower left
Note: this is why it is the most important in capturing the electrical impulse path inside the heart
Limb Lead 3 goes from where to where?
Upper left to lower left
Lead aVF goes to and from where?
From top to bottom
Lead aVR goes to and from where?
From Middle to left
Lead aVL goes to and from where?
From middle to left
What are the “artificial leads”
These leads are calculated by combining the signals from two limb electrodes and the Wilson’s Central Terminal (an imaginary point formed by averaging the voltage of the three limb electrodes)
How many precordial leads are there?
6
V1 and V2 leads look at what?
The right side of the heart
V3 and V4 leads look at what?
The septum of the heart
V5 and V6 leads look at what?
The left side of the heart
A wide QRS complex indicates that there could be an arrtyhmia coming from ________
The myocardium of the ventricals
If you suspect something is wrong on an ECG what is the first thing you should do?
Check the patient
What heart rate is considered too fast?
Too slow?
above 100 or below 60
What should you do if you see something wrong on an ECG but the patient is presenting fine?
Sit the patient down and check the leads
If the ECG reads the patients heart is too fast or too slow, they will likely show symptoms of _______
Poor cardiac output
What produces the S4 heart sound?
Atrial kick against a stiff ventricular wall/hypertension
What produces the S3 heart sound?
Turbulence when filling the ventricals (particularly the left ventrical) during early diastole. Ventricular walls are too compliant (sign of stretch/insufficinecy of the ventricular wall)
The S3 heart sound is potentially indicative of ______ cardioMyopathy
Dilated
When does the S3 heart sound take place?
Early diastole, Right after the closing of the aortic and pulmonary valves
When does the S4 heart sound take place?
Late diastole, just before the closing of the atrioventricular valves.
What kind of cardiomyopathies are associated with the S4 heart sound?
Restrictive Cardiomyopathy and Hypertrophic cardiomyopathy
How will an ECG look coming from the right side of the heart (V1 and V2)
ECG will be inverted because current is moving away from it
If an impulse is traveling perpendicular to an electrode it may create a _______ waveform
Biphasic
If a patient’s ECG is reading with a wide T wave with a long pause afterwards, what is likely happening?
PVC (premature ventricular contraction)
If you have a PVC every 2nd beat what is this called?
Ventricular Bigeminy
If you have a PVC every 3rd beat, what is this this called?
Ventricular Trigeminy
For every 1 litre of blood tranfused a patient needs ______ of rest
30 mins
How wide is a normal QRS wave?
1.5-3 spaces
Junctional rythm usually presents as ____(fast/slow) and with a missing _ Wave
Slow with a missing P wave
Why could P wave inversion be normal?
You’re looking at Lead 3, AVR, or lead v1 v2
(anything looking at right side)
What could be a pathological cause of P wave inversion
Heart block/junctional rhythm
What causes this dip (characterized by rounded edges)
Digoxin medication
A Q wave is normally _______ after a heart attack and 2 days later it is _______
Deep after a heart attack and 2 days later it’s deeper
Why does the Q wave change when you’ve had a heart attack?
Scar tissue from the MI blocks impulses which leads to lower current in that region
What can cause a peaked T wave?
Hyperkalemia or cardiac ischemia
How can hypokalemia effect a T wave?
Flattened T wave
(wack repolarization bc no potassum)
Inverted T waves are associated with
Cardiac ischemia
In what populations is T wave inversion normal?
Normal in children due to heart being smaller
Hypertrophic cardiac myopathy is associated with ________ Inversion
T wave Inversion
Note: T wave inversion also associated with raised intracranial pressure, ischemia, infarction, PE, and Bundle Branch BLock
What is an ectopic beat?
Heart beat coming from area of the heart that has lost the rhythm with the rest of the heart
Identify this rhythm
Premature ventricular contraction
If 2 PVC’s do not look the same, what can you conclude?
They’re coming from 2 different sources
What is the difference between atrial flutter and atrial fibrillation?
Atrial fibrillation is irregularly irregular whereas atrial flutter is regularly irregular
What is torsade de pointe rhythm?
Ventricular tachycardia due to prolonged QT interval
If you see a bundle branch block on an ECG what should you think?
Not lifethreatening on it’s own but it is a warning sign of future issues
A major criteria of a bundle branch block is that the QRS wave takes longer than __s
0.12 seconds
What is the best lead to see a left bundle branch block from?
V6
If you see an M shape on an ECG, what could this mean?
R or L bundlebranch block
What is the best lead to see a R bundle branch block (RSR pattern) from?
V1
During a right bundle branch block, you will see a deep S wave in what 2 leads?
Lead 1 and V6
(both are looking left so it is inverted)
What kind of AV block is normal and may occur in athletes?
First degree AV block
(essentially just the heart rate slowing down normally)
The qualification for a first degree AV block is if the P-R interval is over __ squares on the ECG
5
In a first degree AV block, there is a delay through the AV node, and ____ signals eventually reach the ventricals
all of the signal (Not an actual problem!)
What is the name for a type 1 second degree AV block?
Mobitz (Wenckebach)
What will you normally see in a type 1 Second degree AV block?
Longer PR intervals which leads to eventually skipping a QRS complex
What is more dangerous? A type 1 or type 2 second degree AV block?
Type 2
What is normally seen in a second degree type 2 AV block?
Randomly dropped QRS complex with no increasing PR interval
What is the difference between a type 1 and type 2 second degree block?
Type 1- Lengthened PR interval
Type 2- Consisted PR interval (Shortened QRS complex)
If a patient has a Second degree type 2 or type 3 heart block what to they need in order to work with PT?
A pace maker!!!!
With a third degree AV block (AKA COMPLETE) there is a risk of __________
A-systole (no systole)
What is typically seen in a patient with a 3rd degree AV block?
No synchronization between atria and ventricals
Patient’s with long term atrial fibrillation are more likely to have a ______
Stroke
If a patient has long term atrial fibrillation what medication should they be on?
Blood thinner to prevent stroke
Patients with mitral valve disease may develop _____ -fib
Atrial fibrillation
Because the mitral valve is not closing and it regurgitates blood to the atrium and dilates the atrium
