#### Quick reference from Dubin

What 5 things should you quickly scan for on an EKG?

1. Rate
2. Rhythm
3. Axis
4. Hypertrophy
5. Infarction

Rate

Say '300, 150, 100, 75, 60, 50'
Brady: cycles / 6sec X 10

Rhythym

�Identify basic rhythm
�Scan tracing for prematurity
�Pauses
�Irregularity
�Abnormal waves
CHECK FOR:
-- P before each QRS
-- QRS after each P
-- PR intervals (for AV blocks)
-- QRS interval (for BBB)
If axis deviation = rule out hemiblock

Axis

�QRS above or below baseline for axis quadrant
-- normal vs. R or L axis deviation
�For axis degrees = isoelectric QRS in a limb lead of axis quadrant using the 'axis n degrees' chart
�Axis rotation in horizontal plane = chest leads find 'transisional' QR

Hypertrophy

P waves for atrial hypertrophy
CHECK V1:
-- R wave for RVH
-- S wave depth in V1
---- (+) R wave hight in V5 for LVH

Infarction

-- Q waves
-- Inverted T waves
-- ST segment elevation or depression
Find location of pathology (in LV) & identify occluded coronary artery

Determine rate by observation

Fine division / rate association

May be calculated: 1500 / mm between similar waves = RATE

�Cycles / 6 sec X 10 = RATE
�10 large squares between similar waves = rate is 30/min

Sinus rhythm

�Origin = SA node = SA node
�Normal sinus rate = 60 - 100 BPM
��� Rate > 100 BPM = sinus tachycardia
��� Rate < 60 BPM = sinus bradycardia

Determine any co-existing, independent (atrial/ventricular) rates: dissociated rhythms

�Sinus rhythm (or atrial rhythms) may co-exist with an independent rhythm form an automaticity focus of a lower level
�Determine rate of each

Irregular rhythm

EX: a fib
Always note:
��� general (avg) ventricular rate = QRS /6 sec X 10
OR
��� Pulse

For rhythm
Identify what
Always check

Identify: basic rhythm
-- scan entire tracing for pauses, premature beats, irregularity and abnormal waves
ALWAYS CHECK:
-- P before each QRS
-- QRS after each P
-- PR intervals (for AV blocks)
-- QRS intervals (for BBB)
�Has QRS vector shifted outside no

Sinus arrhythmia

�Irregular rhythm - varies with respiration
�All P waves identical
�Considered normal

Wandering Pacemaker

�Irregular rhythm
�P waves change shape as pacemaker location varies
�Rate < 100 BPM

If rate exceeds 100 BPM in wandering pacemaker then it is called

Multifocal atrial tachycardia

Atrial fibrillation

�Irregular ventricular rhythm
�Erratic atrial spike (no P waves) from multiple atrial automaticity foci
�Atrial D/C may be difficult to see

Escape rhythm

Heart's response to pausing in pacing
�Unhealthy SA node
-->> fail to emit pacing stimulus = sinus block
-->> this pause may evoke escape beat from automaticity focus
�Sick SA node
-->> cease pacing = sinus arrest
-->> causing automaticity focus to 'escap

Atrial Escape Beat/ Rhythm

Then SA node usually resume pacing

Junctional escape beat

Rate: Regular
Rhythm: NSR w/ ...
P wave: Before/after/absent - inverted
PR: absent
QRS: Normal
*** AV AFTER expected
Then SA node usually resume pacing

Ventricular escape beat

Rate: Normal
Rhythm: NSR w/ ...
P wave: Normal
PR: Normal
QRS: Normal (wide beat)
*** AFTER expected
Then SA node usually resume pacing

Atrial escape rhythm

Rate: 60-80 BPM
regularity: regular
P waves: normal but not same as SA node P waves
PR interval: .12-.20 seconds
QRS duration: .04-.12 seconds

Junctional Escape Rhythm

Rate: 40 to 60bpm
Regularity: Regular
P-wave: inverted, absent, or occur after the QRS-complex
QRS-complex: normal
PR-interval: short or absent
'idiojunctional rhythm'

Ventricular Escape Rhythm

- originates in purkinje fibers
- rate 20-40
'idioventricular rhythm'

Premature beats

�From an irritable automaticity focus
This may produce:
��� Premature atrial beat
��� Premature junctional beat
��� Premature ventricular contraction

Premature atrial beat

P' wave earlier than expected and too-tall T wave

Premature junctional beat

Early QRS with no P wave (or inverted) and widened QRS (NO SINUS PAUSE)

Premature ventricular contraction (PVC)

May be:
-- multiple
-- multifocal
-- in runs
-- coupled with normal cycles

Tachyarrhythmia rates

Paroxysmal (sudden) tachycardia

Rate: 150-250 BPM
Supraventricular tachycardia
�� Paroxysmal atrial tachycardia
�� P.A.T. with block
�� Paroxysmal junctional tachycardia
�Paroxysmal ventricular tachycardia

Paroxysmal atrial tachycardia (PAT)

�Irritable atrial focus D/C at 150-250 BPM
�Produces normal wave sequence if P' waves visible

P.A.T. with block

Same as PAT but only every second (or more) P' wave produces a QRS

Paroxysmal ventricular tachycardia

Ventricular focus produces a rapid (150-250/min) sequence of (PVC-like) wide ventricular complexes