Download Rhythm Recognition

Adel Hasanin, MRCP (UK), MS (Cardiology)
Adel Hasanin, MRCP (UK)
Generation and Conduction of
Electrical Current in the Heart
Junction
Adel Hasanin, MRCP (UK)
Electrocardiograph Paper
1 mm
=
0.1 mV
1
m
V
0.5
mV
1 second
------
►
1mm=0.04 sec
------0.2
sec
The time is measured horizontally and the voltage is measured vertically.
► Each
1 second is represented by 5 large boxes (each large box represents 0.2 second)
►
Each large box is divided horizontally into 5 small boxes (each small box represents 0.04 second)
►
Each 1 mV is represented by 2 large boxes (each large box represents 0.5 mV)
►
Each large box is divided vertically into 5 small boxes (each small box represents 0.1 mV)
Adel Hasanin, MRCP (UK)
ECG Waves and Intervals
• Normal P wave = impulse
generated at sinus node and
conducted through the atrium
• Normal PR interval = impulse
conducted through the AV node
to the ventricle
• Normal QRS = impulse generated
above the ventricle and
conducted through both bundles
to the ventricles
• ST-T = ventricular repolarization
Adel Hasanin, MRCP (UK)
PR Interval
►
PR interval Represents the
interval from the onset of atrial
depolarization to the onset of
ventricular depolarization (i.e.
The atrial depolarization plus
the physiological delay at the
AV node).
►
Measured from beginning of the
P wave to beginning of the
QRS.
►
PR
Interval
Normal PR interval = 0.12 – 0.2
sec. (3-5 small boxes)
Adel Hasanin, MRCP (UK)
QRS Complex
► QRS
complex Represents the
simultaneous depolarization of
both right and left ventricles
► Normal
QRS duration ≤ 0.11
second (~ 3 small boxes)
Adel Hasanin, MRCP (UK)
Narrow vs. Wide QRS Complex
►
Normal (narrow) QRS implies:
 beat arising from above the ventricle
(SAN, atrium, or junction) and
conducted normally
►
Wide QRS complex implies:
 Beats arising from the ventricle (PVC, VT,
electronic pacemaker)
or
 Beats arising from above the ventricle but
abnormally conducted due to
► BBB
or
► Accessory pathway
Adel Hasanin, MRCP (UK)
Systematic Rhythm recognition
Rhythm analysis implies:
1. Identifying site of impulse formation (sinus, atrium,
Junction, ventricle)
2. Identifying the sequence of impulse conduction
To identify the heart rhythm, answer the following 5
questions:
1.
2.
3.
4.
5.
Are normal P waves present?
Is PR interval is normal?
Are the QRS complexes narrow or wide?
Is the rhythm regular or irregular?
Adel Hasanin, MRCP (UK)
Is the HR normal, fast, or slow?
1) Are P waves present?
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is slow → junctional
rhythm
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is normal → accelerated
junctional rhythm
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is 100-130 → junctional
tachycardia
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is 150-250 → SVT
Adel Hasanin, MRCP (UK)
1) Are P waves present in normal morphology?
Normal P wave before each QRS
and normal PR interval, QRS is
narrow, rhythm is regular and HR is
normal → NSR
P waves replaced with saw teeth
waves and QRS is narrow →
Atrial flutter
P waves replaced with fibrillatory
waves, QRS is narrow and
rhythm is irregular→ AF
Adel Hasanin, MRCP (UK)
2) PR interval?
PR interval is prolonged, QRS is
narrow and rhythm is regular→
First degree AV block
PR is variable with dropped beats
, QRS is narrow and rhythm is
irregular → 2nd degree mobitz I
(wenckebach phenomenon)
PR is constant with dropped beats
, QRS is narrow and rhythm is
irregular → 2nd degree mobitz II
PR is extremely variable, QRS is
wide, Rhythm is regular and HR is
slow → 3rd degree AV block
Adel Hasanin, MRCP (UK)
3) Are the QRS complexes narrow or wide?
Wide QRS regular tachycardia
and no visible normal P waves →
ventricular tachycardia
Wide QRS regular bradycardia, no
relation between the P waves and the
QRS complexes → complete heart
block
Wide QRS regular bradycardia
and no P waves →
idioventricular rhythm
Wide QRS rhythm and spike
before each QRS → Pacer
rhythm
Wide QRS complex(es) comes
earlier than expected
(irregularity) → PVC
Adel Hasanin, MRCP (UK)
Polymorphic VT (Torsades de pointes)
Spindles & Nodes
Adel Hasanin, MRCP (UK)
3) Are the QRS complexes narrow or wide?
Sinus Tachycardia
AF
SVT
VT
Pacemaker Rhythm
LBBB
LBBB
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RBBB
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Adel Hasanin, MRCP (UK)
Ventricular Fibrillation
Adel Hasanin, MRCP (UK)
4) Is the rhythm regular or irregular?
CHB
Regular rhythm
2ͦ AV Block Mobitz 1
Regular irregularity
AF
Irregular irregularity
PAC
Additional rhythm event
Adel Hasanin, MRCP (UK)
PAC
5) Is the HR normal, fast, or slow?...Heart rate can be
calculated in 2 ways
1. Divide the constant 300 by the number of large boxes in single cycle (single RR
interval) or divide the constant 1500 by the number of small boxes in single cycle
300/4=75
1500/20=75
7x10=70
Adel Hasanin, MRCP (UK)
2. Count cycles (number of RR intervals)
in 6 seconds (30 big boxes) and multiply by 10
5) Is the HR normal, fast, or slow?
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is slow → junctional
rhythm
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is normal → accelerated
junctional rhythm
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is 100-130 → junctional
tachycardia
P wave is not visible or retrograde,
QRS is narrow, rhythm is regular
and HR is 150-250 → SVT
Adel Hasanin, MRCP (UK)
5) Is the HR normal, fast, or slow?
Wide QRS regular bradycardia
and no P waves →
idioventricular rhythm
Wide QRS regular rhythm, no
P waves and HR is normal →
accelerated idioventricular
rhythm
Wide QRS regular tachycardia
and no visible normal P waves
→ ventricular tachycardia
Adel Hasanin, MRCP (UK)
Sinus Bradycardia
Adel Hasanin, MRCP (UK)
Asystole (Flat Line)
Adel Hasanin, MRCP (UK)
Adel Hasanin, MRCP (UK)