EKG Rhythms Flashcards
What are the 4 major narrow complex tachycardias?
- Sinus Tachycardia
- Paroxysmal Supraventricular Tachycardia
- Atrial Flutter
- Atrial Fibrilation
What are three types of Paroxysmal Supraventricular Tachycardia
- AV nodal reentrant Tachycardia (AVNRT): Dual AV nodal pathways like
Wolff Parkinson White - Atrioventricular reentrant tachycardia (AVRT) - “typical” SVT
- Multifocal Atrial Tachycardia
Of the narrow supraventricular tachycardias, which are regular (5)?
Sinus tachycardia,
Atrial tachycardia, or
Atrial flutter with pure 2:1 (or rarely 1:1) conduction,
Atrioventricular nodal reentrant tachycardia (AVNRT) - SVT, and Atrioventricular reentrant tachycardia (AVRT) - WPW
are very regular.
Of the narrow supraventricular tachycardias, which are irregular (3)?
Atrial fibrillation,
Multifocal atrial tachycardia and Atrial flutter or Atrial tachycardia with variable degrees of atrioventricular (AV) block are irregular.
How do we determine the rate of EKG via big boxes?
300 / number of big boxes between R-R. only works for regular rhythms
What is a hallmark of SVT (AVRT) on EKG?
No p waves or retrograde p waves after the QRS
Hallmark of Multifocal Atrial Tachycardia on EKG?
3 or more morphologically different P waves and Irregular
What is the wide regular tachycardia?
Monomophric Ventricular Tachycardia
What are the wide irregular tachycardias?
Polymorphic Ventricular Tachycardia (Tdp)
Ventricular Fibrillation
EKG for sinus bradycardia
PR interval and QRS
Normal PR Interval and no dropped QRS.
EKG for 1st Degree AV Block
PR interval and QRS
PR interval - Prolonged greater than 0.2s
No drop in QRS
EKG for 2nd Degree AV Block Type 1
PR interval and QRS
Progressively longer PR
Dropped QRS
EKG for 2nd Degree AV Block Type II
PR interval and QRS
PR Constant
Drops QRS
Visible QRS usually widened
EKG for 3rd Degree AV Block
PR interval and QRS
AV Dissociation - no communication
What should a normal axis look like? What leads do you look at?
Look at Lead I and aVF.
Are P and QRS both upright?
If aVF is equiphasic, count as up.
if yes, Normal Axis
What would left axis deviation look like? What leads do you look at? Where do you look to confirm?
Look at Lead I and aVF.
If Lead I is positive and aVF is more negative - it is likely Left Axis Deviation.
Look at Lead II to confirm. If it is equal phasic, it is indeterminate.
If Lead II is more negative, then Left Axis Is Deviated.
If Lead II is positive, it is a normal axis.
Causes of Left Axis Deviation
Things that alter LV depolarization
-LBBB
-LVH
-LAFB (left anterior fascicular block)
Normal Variant in Obese People
What would right axis deviation look like? What leads do you look at? Where do you look to confirm?
Look at Lead I and aVF
If Lead I is negative and aVF is positive you have right axis deviation.
Causes of Right Axis Deviation
-RBBB
-RVH
-LPFB (left posterior fascicular block)
-COPD, PE
-WPW
-Previous Lateral/Ant MI (LV atrophy, can’t conduct)
Can be a normal variation in tall/slender people
EKG changes for extreme right axis deviation
Both Lead I and aVF downward reflected
Characteristic EKG changes of Wolf Parkinson White
- Delta wave
- Short PR interval
- QRS greater than 120ms
Some causes of prolonged QT interval (>500ms)
Anti-Arrthymics
Anti-Biotics
Anti-psyChotics
Anti-Depressants
Anti-Emetics
-Hypo K, Mg, Ca
Some causes of short QT interval (<460ms)
Hyperkalemia, Hypercalcemia
Where to look for EKG changes for left atrial enlargement
Lead II and V1
Is lead II p wave biphasic with a sort of dicrotic-looking notch? Then look at V1.
Is V1 a biphasic but mostly negative deflection at the terminal end?
If both yes, it is indicative of left atrial enlargement.
Causes of left atrial enlargement
Left Heart Failure
Cardiomyopathy
Mitral Disease
Where to look for EKG changes for right atrial enlargement?
Lead II and V1
Lead II p-wave tal, greater than or equal to 2.5mm. Then look at V1, if initial component is larger than second of p-wave - indicative of RA enlargement
Causes of right atrial enlargement
Pulmonary HTN
Tricuspid Disease
Where to look on EKG for LBBB
Look at V5 and V6. Does it have a notched R wave? If yes, could be LBBB
Look at V1 and V2. Does it have a rS morphology? Deep (negative) S wave.
Where to look on EKG for RBBB?
First look at V1 and V2 - does it have a rSR’ morphology? (bunny ears)
Next look at V5 and V6. qRs, Is there a wider, slurred s wave?
- if yes to both, RBBB indicated
Where to look for EKG changes indicating LVH
Lead V1 and V2 - Deep S Waves
Then V5 and V6 - Tall R Waves
2 causes of LVH
Aortic Stenosis
Hypertension
Where to look for EKG indicating RVH
V1 and V2 - Tall R wave
V5 and V6 - Deep S wave
Name a cause of RVH
Pulmonary HTN
When assessing for ST depression, where should you first look and what are you looking for?
V2 and V3 - ST Depression 0.5mm or more
All other leads >1mm
Horizontal and/or Down-Sloping ST Depression in two contiguous leads
What morphology of ST depression is less indicative of ischemia?
An upsloping ST depression
ST depression and T wave inversion can be indicative of?
If trops positive - NSTEMI
If trops negative - Unstable Angina
Digoxin Toxicity, Hypokalemia
Which is more concerning: ST Elevation with a concave or Convex morphology
Convex
What amount of elevation is concerning for ST Elevation in all leads? Is there an exception?
New ST elevation at the J point in two contiguous leads of 0.1mV in all leads EXCEPT V2 and V3.
V2 and V3: greater than or equal to 0.2mV in men 40 years old or more
greater than or equal to 0.25mV in men less than 40
greater than or equal to 0.15mV in women
Causes of ST elevations
STEMI
Pericarditis
Hyperkalemia
How can you differentiate between Pericarditits and STEMI
Pericarditis usually has a concave ST elevation shape and more diffuse across almost all leads
What is the difference between Atrial Tachycardia and Multifocal Atrial Tachycardia?
AT: 3 or more consecutive PACs coming from a single atrial focus, having identical, NON-SINUS, P-wave morphology
MAT: 3 or more consecutive different morphologies P waves
MAT most commonly occurs in patients with?
chronic lung disease
Longer runs, or chronic, atrial tachycardias are usually treated with?
Antiarrhythmics or Ablations
An isolated posterior MI is treated as a STEMI. What would you see on a regular 12 lead EKG that would make you want to investigate and consider a posterior 12 lead?
ST depression in Anterior leads (V1-V2) may indicate the presence of a posterior MI
When assessing for R wave progression, what direction of the chest leads do you expect the R wave to go from smaller to larger?
V1 smallest -> V5-6 biggest
What leads do you review for R wave progression?
Precordial / Chest Leads
As the R wave gets bigger, what happens to the S wave?
As R wave gets bigger, S wave gets smaller
What are the characteristics of an Accelerated Idioventricular Rhythm?
3+ consecutive ventricular beats that are faster than regular intrinsic ventricular beats >40bpm, but slower the vTach which is >100
1st degree AV Block has a PR interval greater than?
0.2s or 200ms
What is the difference in PR interval between 2nd-degree type II and 3rd-degree AV block?
2nd degree type II has a consistent PR interval
The atrial rate is always faster than the ventricular rate in 3rd degree
Your potassium is ~5.5 or greater; what EKG findings could you see?
QRS > 0.20, no visible p waves, Peaked T wave in MORE THAN ONE LEAD.
Your potassium is less than ~2.7; what ekg changes could you see?
Prominent U wave due to delayed ventricular repolarization. Small or inverted T-wave may or may not be visible.
What are some ECG changes that could occur with hypermagnesemia - Mag > 10
Delayed intraventricular conduction, prolonged QT interval, first-degree heart block, Can progress to worsening blocks
ECG findings with hypomagnesemia Mg<1.0
Prolongation of QT and PR intervals
With what electrolyte disturbance would you see an Osborn or J wave? What condition can also produce J waves?
Hypercalcemia - send troponins AND a calcium level.
Hypothermia
What ECG changes can you see with hypercalcemia?
Shortening the ST segment corresponds to shortening or QT.
Osborn Wave / J wave
T waves usually have a gradual ascending limb and a steeper descending limb. What electrolyte disturbance may cause a reverse of this, steep ascending and gradual descending?
Hypercalcemia
Atrial Flutter is commonly a macro-reentrant tachycardia, what does that mean?
Develops a circuit within the RA where the impulses keep firing at the AV node.
What is Sick Sinus Syndrome? How does it manifest? How is it treated?
Irreversible dysfunction of SA node. Idiopathic, “normal” wear of the heart.
Manifests as SB, sinus arrest, SA block, tachybrady syndrome
Tx: Permanent Pacemaker
Normal T wave morphology. How should the ascending and descending parts of the wave look?
Upstroke should be slower and downstroke should drop / be steeper.
Think rollercoaster
In a normal EKG, the T wave is always upright in what leads?
Leads I, II, V3-V6
And inverted in aVR (if it’s not, we have some sort of pathology going on)
T waves may be flipped in what leads as a normal variant
V1 and V2 (maybe V3)
What is the normal degree range for the QRS axis
-30 to 90 degrees
If you’re having extreme right axis deviation, that means electrical activation is originating from?
The ventricles. Bad news, bears.
Causes of extreme right axis deviation
VT
Accelerated Idioventricular Rhythm (death of primary pacer cells)
Massive MIs
Severe RVH
Hyperkalemia
What is an incomplete Right BBB or LBBB?
It meets the morphology criteria, but it is within normal QRS duration. Less than 0.12s.
In a LBBB, which ventricle depolarizes first?
Right Ventricle, then Left Ventricle
What is the most common intraventricular conduction defect?
Left Anterior Fascicular Block (LAFB)
What do you expect to see on an EKG with a patient with a Left Anterior Fascicular Block?
Left Axis Deviation
rS complexes in II, III, aVF
qR complexes in I and/or aVL
