EKGs Flashcards
what bundles caries the message from the RA to the LA?
bachmann’s bundle
what does the p wave indicate
atrial depolarization
with a right bundle branch block what will happen?
The QRS will be wider
what does the t wave represent
ventricular repolarization
what should the QRS be less than?
120 msec
time it takes to conduct through the AV node
PR segment
how long should the PR interval be?
0.12-0.20 sec
if there is an incomplete bundle branch block what will the length of the QRS be?
100-120
when would the PR interval be less than 120 msec? there is a delta wave
Wolff-Parkinson-White
What causes the delta wave with Wolff-Parkinson-White
accessory pathway
get an early depolarization of ventricles
“slurring” of the R wave
why is the only way to get the conduction from atria to ventricles an AV node?
non-conductive material between
if the PR interval is longer than 200 msec what in there?
a block
when should the T wave end?
before 1/2 the distance b/w each R wave
what happens when the T wave ends longer than 1/2 the distance b/w R waves
Long QT interval
what is limb lead I
right arm to left arm
what is limb lead II
right arm to left leg
avR
right shoulder
avF
foot (vertical line)
avL
left shoulder
for inferior what 3 leads do you look at?
II, III, aVF
what leads tell you the lateral side of the heard?
I, aVL, V5, V6
what leads tell you the septal part of the heart
Vi, V3
what leads for anterior part of the heart
V3,V4
if the movement of electricity is traveling towards the positive end of the lead what do you get?
a positive deflection above baseline
will the QRS with aVR point up or down?
down
II, III, and aVF should look how?
very similar
they are all looking up at the heart
do you look at aVR for pathology
rarely
what should you look at with the precordial leads
normal R wave progression
how does the R wave change as you go from V1-V6
R wave should have a large amplitude (can drop a bit a V5 and V5 since it is more lateral)
how is limb lead III orientated?
down and to the right
5 things to look for on an EKG
Rate Rhythm and Blocks Axis Hypertrophy Infarction
what is the ectopic atrial rate
60-80
what is the AV junctional rate
40-60
what is the ventricular rate
20-40
what is bradychardia
<60
what is tachycardia
> 100
one small box is how many sec
0.04
how many sec in a big box
0.20 sec
one large box is equal to how much of a minutes
1/300 of a minutes
what is the order for the rate (when counting from R to R with big boxes) can only use for regular rate and rhythm
300 150 100 75 60 50 43 37
if someone’s rhythm isn’t regular how do you identify the rate?
count the R waves in the 6 second interval and multiply by 10
should you count R waves or cycles
cycles (should count between R waves, not actual R wave)
how many large boxes are associated w/ 3 seconds
15 boxes
a-fib longer than how long is there a risk of developing a clot/ stroke?
48 hours
what should you check for rhythm on an EKG?
Is there a p wave before every QRS
Is the rhythm regular?
Check to R to R interval
Make sure p waves are rounded and point in the same direction as the QRS
how do you tell supraventricular versus ventricular rhythm
will be narrow complex with SVT
Premature atrial complex
premature junctional complexes captures the atria (retrograde) and the ventricles (Antegrade)
Retrograde P wave may appear before during or after the QRS
Supraventricular arrhythmia
is a fast rhythm usually fatal?
generally not unless there is an underlying problem
common cause of ectopic beats in the heart
stimulants
If P to P interval of 2 normal cycles is shorter than it should be what type pause is there?
incomplete pause
PAC- resets SA node
what type pause is a PVC associated with?
Complete pause
ventricular response is irreguarly irregular and may be fast (HR>100)
a-fib
R to R interval is consistently inconsistent
Saw tooth appearance May see p waves in V1 Atrial rate 300 Often 2:1 conduction, so HR = 150 Drugs can slow conduction to 3:1, 4:1 etc
A flutter
what can slow conduction to AV node
vagal maneuvers (bearing down)
if they have a-fib and their heart rate is >100 what is it called?
a-fib w/ a rapid ventricular response (RVR)
Lots of p waves of different shapes and sizes
Irregularly Irregular
Most often found in severe COPD patients
Multi focal Atrial Tachycardia
how do you treat SVT?
adenosine
what do you Rx for someone w/ a-fib w/ RVR
CCB or digoxin (to slow conduction)
and coumadin
how many different morphologies of the p waves for it to be multifocal atrial tachycarida
3 or more
where are multi focal atrial tachycardia seen?
people w/ COPD
anything that originates above the ventricles that isn’t sinus tachycardia
SVT
narrow complex, junctional re-entry
narrow QRS, may see a retrograde p wave
Paroxysmal supraventricular tachycardia
3 types of SVT
AV reentry tachycardia
AV Nodal reentry tachycardia
Atrial tachycardia
SVT that doesn’t involve AV node
just between atrial and ventricles
AV reentry tachycardia
Wolff Parkinson White
ectopic area w/i area that likes to depolarize at faster rate than SA node so it overdrives it.
Atrial tachycardia
treatment for Wollf Parkinson White
ablation
beta blocker
how do you treat AV nodal reentry tachycardia to prevent it.
CCB (Diltiazem, verpamil)
tx for ectopic atrial tachycardia
Beta blocker (decreases ionotropic and chronotropic) ablation is 2nd line
will the QRS complex with reentry SVT be narrow or wide?
narrow (normal)
if you have a wide complex tachycardia what must you consider
that this is coming from the ventricles
with re-entry will p waves be normal?
No, may be inverted or retrograde
what will a retrograde p wave look like
a notched t wave
can but right up against QRS
see within QRS
what should the QRS duration be?
<0.1 sec
what do significant q waves mean?
significant for a heart attack
are PVCs common?
Yes
3 variations of V tach
monomorphic
polymorphic
torsade de pointes
what is a Q wave considered significant
width of the q wave is greater than 0.04 sec (wider than one box)
or amplitude of Q wave is >1/3 the height of the R wave
definition of a Q wave
first downward deflection (must be before an upward deflection)
ventricular rhythms have a _______ QRS
wide (ventricles depolarizing at different times)
how do you treat torsades de pointes
magnesium
if every third beat is a PVC what is it called
trigemy
If every other beta is a PVC what is in?
bigemy
Delay or total failure of impulse conduction through a part of the heart
Blocks
PR Interval longer than 200 msec
1st degree AV block
PR interval gets longer until a nonconducted P wave occurs
Mobitz Type I- Second degree AV block
Wenckebach
PR intervals are constant until a nonconducted P wave occurs
Mobitz Type II
what is another way to identify 2nd degree blocks
grouped beating
Complete block of signals from atria to Ventricles
No synchronization between Ps & QRS
P waves normal
HR nodal in 60s or Ventricular in 40s
3rd Degree AV Block
with a bundle branch block the QRS is wider than 0.12 sec
Bundle branch blocks
Mobitz Type I goes away with what?
activity
generally isn’t treated
Tx for mobitz Type II
pacemaker
tx for 3rd degree AV block
pacemaker
what do you see with a bundle branch block
R-R’ waves due to separate depolarizations
QRS must be >120 msec
what leads will a Right BBB show up in?
V1 and V2
What leads will a left BBB shop up best in?
V5 and V6
normal QRS axis is
-30° to +90°.
30° to -90° is referred to as
a left axis deviation (LAD)
+90° to +180° is referred to as a
right axis deviation RAD
what lead do you use to tell if north or south hemisphere
aVF
what lead do you use to tell if axis is in left or right 1/2
lead 1
for atrial hypertrophy what do you look at
Look at lead V1 for biphasic p waves- front end will be bigger with RAH and trailing end will be bigger with LAH (deeper trough)
Or p qwave > 1.5 mm
what is the rule for LV hypertrophy
If amplitude of S wave in lead V1 and R wave in V 5 or 6 exceed 35 mm = LVH
what is the rule for RV hypertrophy
Right axis deviation (>90 degrees)
Tall R-waves in RV leads, deep S waves in LV leads
slight increase in QRS duration
if just the subendocardium dies what do you see
ST segment depression
if the entire endocardium dies what is seem?
STEMI
what does t wave inversion mean
ischemia
what serves the front wall of the heart?
LAD
what serves the posterior lateral part of the heart
left circumflex
what serves the right ventricle, interior
right ventricle
inferior
what does the AV node get it’s blood supply from
RCA in 90%
what will you see on a treadmill stress test w/ a blockage
onset of >2 mm ST segment depression
where do you measure ST segment elevation?
At the “J” point where the S wave joints the ST segment
Tx for inferior MI
lots of fluids- need to up the volume to keep blood moving
what is ST depression in V1-3
posterior MI
what is a tall S wave in limb lead 1 and a deep r wave in aVF
left anterior fasicular block
what is a deep S wave in limb lead I and a tall R wave in aVF
left posterior fasicular block
where does a pacemaker lead go?
through superior vena cava into right atria then down into right ventricle
will have a LBBB on ECG
if there is diffuse ST segment elevation what is it?
pericarditis
peaked T waves indicates what
hyperkalemia
with hypokalemia what do you see
prominent U wave
downsloping ST-segment elevation in leads V1 and V2 and QRS morphology resembling a RBBB
brugada syndrome
