2. What are we actually going to cover?
• Day 1 (Last Week)
• What is an EKG
• Basics
• Rate
• Day 2 (Today)
• Rhythm
• Day 3
– Axis
– Hypertrophy
• Day 4
– Infarction
– Hemiblock
Goals for today:
Determine Rate and if
regular or IRR rhythm.
If IRR name it.
It will come with practice.
3. Waves Practice
1 = 2 =
3 =
4 =
Q wave R wave
S wave
QS wave
Because there is no upward wave, it’s
considered a Q wave.
Q is always first wave in complex
4. 1. Rate
300, 150, 100, 75, 60, 50
• But for bradycardia:
rate = cycles/6 sec. strip x 10
2. Rhythm
ID basic rhythm
• Scan for premature beats, pauses,
irregularity, and abnormal waves
3. Axis
• QRS above or below baseline for Axis
Quadrant (L/R deviations)
• For Axis in Degrees – find isoelectric QRS
in limb lead (use “Axis in Degrees” Chart)
• Axis rotation in the horizontal plane
(chest leads) find isoelectricQRS
4. Hypertrophy
CheckV1
• p-wave for atrial hypertrophy
• R wave for RV hypertrophy
• S wave depth inV1
+ R wave height inV5 for LV hypertrophy
5. Infarction
Scan all leads for:
• Q waves
• InvertedT waves
• ST segment elevation or depression
PREVIEW
5. PQRST Overview
The classic PQRST waveform is from Lead II.
• P:Atrial depolarization
• QRS:Ventricular Depolarization
• T:Ventricular Repolarization
6. PQRST Overview
• P:Atrial depolarization
Based on the perspective of Lead II, this is
positive.
Can also infer that this depolarization takes
longer and is of less amplitude than the
QRS.
10. QRS Complex
SWave: the Purkinje fiber depolarization
Right Left depolarization but considering the
origin…
Still away from the electrode so negative
deflection
11. TWave
RepresentsVentricular Repolarization
Why is it in the same direction of the QRS complex?
Simply, repolarization is the opposite direction but
the surface is becoming more negative (instead of
positive)
14. ID basic rhythm
• Scan entire tracing for premature beats, pauses,
irregularity, and abnormal waves
ALWAYS:
• Check for: P before each QRS
QRS after each P.
• Check: PR intervals (for AV blocks).
QRS interval (for BBB)
• Look for abnormalities (ST segment depression, U waves, ectopic beats, etc.)
• Has QRS vector shifted outside normal range? (to rule out Hemiblock)
NORMAL SINUS RHYTHM
15. NORMAL INTERVALS
• PR Interval 0 .12-0.20 seconds (3-5 small squares)
• QRS complex <0.12 seconds (3 small squares)
• QT Interval (< or equal to .40 sec)
20. Reminder = Horizontal axis
• Normal RWave Progression
• Starts off negative inV1 progresses towards
positive byV6
• Where it becomes more positive than
negative is the transition.
• If the isoelectric lead isV1 orV2 then there
is rightward (counter-clockwise) rotation.
• V5 orV6 = leftward (clockwise) rotation
• V3 or v4 = no rotation
• What is this?
• Refer to a change in the electrical activity
in a horizontal plane through the heart.
23. Sinus Arrhythmia ( Know that this is OK)
• This sounds pathological , but it is normal
• Extremely minimal increase in heart rate during inspiration & extremely minimal
decrease during expiration.
24.
25. Ok, what are all the rhythms?
• Are there P-Waves?
• Are all the P-Waves the same? (P’?)
• Does each QRS complex have a P wave?
• Measure PR Intervals (Yes, all of them)
• Are the PWaves and QRS complexes associated with each other?
• PR Interval
• Are the QRS Complexes Narrow orWide?
• Are there any dropped beats?
• P without a QRS
28. A set of three arrhythmias that all involve ectopic
atrial foci.
1. Wandering Pacemaker
2. Multifocal Atrial Tachycardia
3. Atrial Fibrillation
Although most people refer to Atrial Fibrillation as
specifically the irregularly irregular rhythm.
Irregular Rhythms
29.
30. Wandering Pacemaker
SA Node is normal
Ectopic foci are created by entrance block
Rate < 100 bpm.
Irregularly spaced ventricular depolarizations that are
still normal width
• (Although difficult to tell in this example)
What do you expect the QRS complexes to look like?
• Intact AV Node.
• Normal QRS
31. WANDERING PACEMAKER
What’s the Rate? (Six second strip)
• 70ish BPM (By the six second rule)
• 65ish BPM (by the 1500 rule)
32. WANDERING PACEMAKER
Wait, if the rate is between 60-100… why isn’t this just normal? Sure it
technically should be an irregularly irregular rhythm but can you tell?
How do we know this isWandering Pacemaker?
35. PACEMAKER
Why is the P wave at the light blue arrow in the opposite direction?
Depolarization is going the opposite direction. Also, note the shorter PR
Segment
36. PACEMAKER
Why is the P wave at the light blue arrow in the opposite direction?
Depolarization is going the opposite direction. Also, note the shorter PR
Segment
37. Wandering Pacemaker
SA Node is normal
Ectopic foci are created by entrance block
Rate < 100 bpm.
Irregularly spaced ventricular depolarizations that are
still normal width
• (Although difficult to tell in this example)
What do you expect the QRS complexes to look like?
• Intact AV Node.
• Normal QRS
38. Wandering Pacemaker
• Wandering Pacemaker
• Pacemaker activity wandering from the SA node to nearby atrial automaticity foci. This
produces irregular intervals as well as variation in the shape of the P waves. The overall
rate is however in normal range.
• If the rate should accelerate into tachycardia, it becomes Multifocal AtrialTachycardia.
P’ = automaticity focus producing its own signature.
42. Multifocal Atrial
Tachycardia
SA Node is normal
Ectopic foci are created by entrance block but may be
irritable OR might be a lot more ectopic foci than in
wandering pacemaker.
Rate > 100 bpm.
Irregularly spaced ventricular depolarizations, easier to
tell because of the increased rate.
What do you expect the QRS complexes to look like?
• Intact AV Node
• Normal QRS
46. Multifocal Atrial
Tachycardia
SA Node is normal
Ectopic foci are created by entrance block but may be
irritable OR might be a lot more ectopic foci than in
wandering pacemaker different P-wave morphology
Rate > 100 bpm.
Irregularly spaced ventricular depolarizations, easier to
tell because of the increased rate.
What do you expect the QRS complexes to look like?
• Intact AV Node
• Normal QRS
50. Atrial Fibrillation
SA Node is normal
Ectopic foci are very irritable. Multiple foci firing
randomly AND repeatedly. P:QRS is no longer 1:1
Rate is variable.
• Ventricular rate is very variable
Irregularly spaced ventricular depolarizations
What do you expect the QRS complexes to look like?
• Intact AV Node
• Normal QRS
51. Atrial Fibrillation
“Bag of Worms”, no coordinated muscle
contractions.
How is this compatible with life?
Atrial Kick?
• Decrease in CO, Causes increased sympathetics,
worsens irritation
Mortality related to stroke
52. Atrial Fibrillation
Key difference from WP and MAT?
• P wave to QRS complex ratio is not 1:1
Multiple P waves aren’t communicated into a
QRS complex.
• Too many and not coordinated enough.
Atrial foci are parasystolic = insensitive to
overdrive suppression
53. Atrial Fibrillation
What’s the rate on this six second strip?
90bpm.
The QRS rate is 90bpm but the P wave rate is >>>100bpm.
55. Atrial Fibrillation
A.) Controlled Atrial Fibrillation
B.) Uncontrolled Atrial Fibrillation or Atrial Fibrillation with Rapid Ventricular Response
• Worse CO than controlled A-Fib and suggests worse damage, ischemia, possible issue with
junctional area
A
B
60. Escape Beats and
Rhythms
Escape beats and rhythms occur when
there is a pause in the SA Node.
When there is a pause then any of the
other tissues can initiate a beat or
rhythm.
61. Escape Beats and
Rhythms
Most likely the tissue that is likely to
fire is of atrial origin
• Because they have higher rates.
62. Escape Beats and
Rhythms
If the SA Node pause is short then a
single beat escapes.
This errant depolarizations then helps
to restart the SA Node.
This is called an SA Node Block and
results in an escape beat.
65. Atrial Escape Beat
Where is the Atrial Escape Beat?
Notice the SA Node pause and the morphology of the P Wave that suggests it is of
different origin than the SA Node.
66. Atrial Escape Beat
Also, note that following this escape beat the original P-Wave morphology and rate
returns.
68. Atrial Escape Beat
Does this escape beat originate in the atria or the ventricles?
The atria. Notice how the QRS is still normal width.
It doesn’t look like this…
69. Escape Beats and
Rhythms
If the SA Node pause is short then a
single beat escapes.
This errant depolarizations then helps
to restart the SA Node.
This is called an SA Node Block and
results in an escape beat.
70. Escape Beats and
Rhythms
use lasts for several
es then an “escape
beats) occurs.
depolarizations
the SA Node which
vere damage.
A Node Arrest.
71. Sinus Arrest
• Sinus Arrest occurs when a very sick SA Node ceases pacemaking
completely. But the hearts efficient, failsafe mechanism provides three
separate levels of automaticity foci for backup pacemaking.
74. Origin of the Escape
Beat/Rhythm
• SA Node Block
• To the Normal Activation Sequence.
75. If the SA Node fails which “structure”
will take over the rate?
• If we just consider the rate then the
Atrial Myocardium is the most likely
tissue to send depolarization.
Origin of the Escape
Beat/Rhythm
77. What would a Ventricular Escape Beat
look like?
If the escape beat (or rhythm)
originates from the ventricular tissue,
then it bypasses the AV Node.
What would the QRS complex look
like?
Origin of the Escape
Beat/Rhythm
78. Ventricular Escape Beat
And we looked at this already. Here is an Atrial Escape Beat compared to a Ventricular
Escape Beat.
Disregard the baseline artifact in B. Just focus on the timing of the QRS waves.
A
B
83. Ventricular Escape Beat
Why is there a P-wave (ectopic) for an Atrial Escape Beat but no P-wave for a ventricular
escape beat?
A
B
84. Ventricular Escape Beat
Wait… did the SA Node, atrial and junctional foci not fire either? Yep
Parasympathetic activity on the heart has an effect on nodal and atrial tissue but not ventricular
tissue.
Ventricular Beats commonly come from a blast of parasympathetic activity and more often during
sinus bradycardia.
A
B
85. What about a Junctional Escape Beat?
Junctional refers to being at or near the
AV Node.
Origin of the Junctional
Beats/Rhythms
86. What about a Junctional Escape Beat?
Junctional refers to being at or near the
AV Node.
Origin of the Junctional
Beats/Rhythms
87. QRS Morphology:
A QRS complex that originates from a
junctional foci can either look normal
or be slightly wider than a normal QRS
complex.
Origin of the Junctional
Beats/Rhythms
88. QRS Morphology:
A QRS complex that originates from a
junctional foci can either look normal
or be slightly wider than a normal QRS
complex.
What?
Origin of the Junctional
Beats/Rhythms
89. Identifying junctional origins of any
ectopic foci is notoriously difficult.
Depending on where in the “junctional
area” (AV Node area)
Note the P-wave location and direction.
Not depicted in these diagrams but if
the junct
Origin of the Junctional
Beats/Rhythms
90. Not depicted in these diagrams but as
the ectopic foci enters more into the
ventricular tissue the QRS complex will
become wider.
Origin of the Junctional
Beats/Rhythms
91. Junctional Escape Beat
“A” represents a junctional foci that is closer to the ventricles or at the midway point
(Difficult to interpret)
“B” represents a junctional foci that is closer to the atria
A
B
98. Escape Rhythms
How can you tell that it’s a rhythm and not just a single beat?
• The rate is different than the initial rhythm.
• Look at the P-waves
What’s the rate of the escape rhythm?
<75bpm
A
99. Escape Rhythms
Obviously a Ventricular Escape Rhythm…
• SA Node pause
• Wide QRS complexes… many of them.
What’s the rate of the escape rhythm?
< 50bpm
B
100. Escape Rhythms
Well it says Junctional Escape Rhythm… but would you be able to tell?
• P-waves are missing or occluded?
• QRS complex looks the same as during the SA Node initiated depolarizations.
What is the rate of the escape rhythm here?
<50bpm, so this might be a clue that it is a junctional rhythm and not atrial.
C
101. Escape Rhythms
For beats, it would be difficult to
tell junctional apart from atrial.
But for rhythms, if you calculate
the rate you can assume
junctional vs atrial based on
their intrinsic rates.
102. Beat or Rhythm?
Note the SA Node delay…
Is this an Escape Beat or an Escape Rhythm?
More difficult to tell when the rate is slower.
103. Beat or Rhythm?
This is a beat.
Note that the original P-wave returns which suggests SA Node function has returned.
104. •Bradycardia with ventricular rate <40bpm
•Wide QRS complexes (120ms)
•Regular non-conducted P waves (complete heart block)
or no P waves (sinus arrest)
Ventricular escape beats can also occur after a long
pause (sinus arrest) if atrial or junctional escape is not
triggered.
•Ventricular escape in the setting of sinus arrest:
Ventricular Escape Rhythm
110. Overview
Premature beats are from irritated foci
that fire randomly. (But not randomly
and repeatedly)
Which of these two is a premature beat
and which one is an escape beat?
111. Overview
The top figure represents an escape
beat. Notice the pause between beats
then a missing P-wave
The bottom figure is an atrial
premature beat.
How do you know it’s atrial (or at least
supraventricular?)
Because of the normal QRS complex.
112. Overview
SA Node is normal
Ectopic foci are created by irritation
Irritated foci = single spontaneous
beats
Atrial/Junctional foci will still produce
normal-ish QRS
Ventricular foci will produce wide QRS
complexes
113. Premature Beats:
Irritation
Atrial/Junctional Ventricular
Caused by increased
sympathetics, adrenaline
Less affected by
sympathetics
Less affected by hypoxia More affected by Hypoxia
Caffeine, cocaine,
amphetamines
Hypokalemia
Less affected by stretch More affected by stretch
Understanding location of foci helps us to diagnose and
has different management/treatment
114. Premature
Atrial/Junctional Beats
• A: 2nd depolarization
represents a PJB where the p
wave is masked.
• B: 5th depolarization
represents a PJB with a foci
that is more atrial than
ventricular.
• C: 4th depolarization
represents a PAB with a
P’wave
A
B
C
118. Premature Ventricular Contraction
Premature Ventricular Beat or Premature Ventricular Contraction (PVC)
The irritated foci is of ventricular origin, note the widened QRS then return to the original
SA Node rate.
119. “A” is a single PVC.
“B” represents multiple PVCs paired with a normal QRS. This is called “Bigeminy”
And specifically this one is Ventricular Bigeminy
A
B
122. “B” Ventricular Bigeminy
“C” Ventricular Trigeminy
B
C
D
E
“D” Paired PVCs
“E” PVC Triplet
Which side (left or right) represents more irritated/damaged tissue?
The right side.
As cardiac tissue gets more and more irritated we get closer to looking like sustained Ventricular
Fibrillation. Which is the next topic “Tachy-Arrhythmias”.
126. Tachyarrhythmias
Three basic patterns and all are based
on the rate.
Paroxysmal Tachycardia: 150 – 250bpm
Flutters: 250 – 350bpm
Fibrillations: 350 – 450bpm
127. Irritation
Atrial/Junctional Ventricular
Caused by increased
sympathetics, adrenaline
Less affected by
sympathetics
Less affected by hypoxia More affected by Hypoxia
Caffeine, cocaine,
amphetamines
Hypokalemia
Less affected by stretch More affected by stretch
This still applies as it did with premature beats but
tachyarrhythmias suggests worsening severity
128. Tachyarrhythmias
Supraventricular vs Ventricular
Remember that Supraventricular refers
to atrial/junctional foci.
Which one will have a normal QRS and
which one will have a widened QRS?
Supraventricular Tachycardia
Ventricular Tachycardia
133. Tachyarrhythmias
For a good cardio workout it’s
recommended to keep your
heart rate at 55-85% of your
MHR.
MHR = 220 – your age.
That can definitely be above
150bpm.
A
B
134. Tachyarrhythmias
It’s about context.
“Paroxysmal” tachycardias mean that it
happens for no reason and randomly.
If you’re working out and your heart
rate goes above 150 then that’s
physiological.
If you’re sitting in a chair and your heart
randomly goes to 200 then back down
to 60-100, that’s a problem. That
suggests very irritated heart tissue.
A
B
138. Tachyarrhythmias
“A” – Paroxysmal
Supraventricular Tachycardia is
irritation of the atria/junctional
region.
“B” – Paroxysmal Ventricular
Tachycardia is irritation of the
ventricular tissue.
What part of the heart is irritated
in “C”
A
B
C
139. Tachyarrhythmias
“C” – Ventricular Escape Beat
Pathology for escape rhythm is
an arrest of the SA node.
Ventricular tissue here is
working as intended.
A
B
C
143. Atrial
Tachyarrhythmias
Of course the rate increases as
we go from flutter
fibrillation but also note the
irregular, uncoordinated
depolarizations occurring.
A
B
C
146. Ventricular
Tachyarrhythmias
Wide QRS complexes
Again, the difference in
pathology between flutter and
fibrillation is not just rate.
One rapidly discharging very
irritable foci vs many
discharging irritable foci.
Note the waveforms and the
mV produced.
A
B
C
147. Ventricular
Tachyarrhythmias
Wide QRS complexes
Again, the difference in
pathology between flutter and
fibrillation is not just rate.
One rapidly discharging very
irritable foci vs many
discharging irritable foci.
Note the waveforms and the
mV produced.
A
B
C
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