This document provides information on cardiac arrhythmias, including: - The normal cardiac conduction system and blood flow through the heart. - Definitions and characteristics of various normal and abnormal sinus rhythms, atrial rhythms, junctional rhythms, and ventricular rhythms based on heart rate, rhythm, P wave presence and morphology, PR interval, and QRS width. - Key arrhythmias summarized include normal sinus rhythm, sinus bradycardia, sinus tachycardia, premature atrial contractions, atrial fibrillation, atrial flutter, premature junctional contractions, junctional tachycardia, premature ventricular contractions, ventricular tachycardia, and ventricular flutter.

1. Cardiac
Arrhythmias
DR ABID NAEEM

2. Anatomy & Physiology
• Blood Flow through
heart
– Superior and Inferior
Vena Cava
– Right Atrium
– Right Ventricle
– Pulmonary Artery
– Lungs
– Pulmonary Vein
– Left Atrium
– Left Ventricle
– Aorta
– Body

3. Sinus
1-Sinus Rythem-HR-60-100/M
2-Sinus Arrythmia-HR-60-100/M
3-Sinus Arrest- Sinus arrest- sinus stop-one
beat miss
4-Sinus Bradycardia-HR-<60/M
5-Sinus Tachycardia-HR-100-160/M. >160
SVT

4. Atrial
1 -Wandering pace maker-HR-<60
2-Premature Atrial Contraction-HR-NA(Not
Assessable)
3-Atrial Tachycardia-HR-160-250/m
Atrial flutter-hr-250-400/m-P-regular
5-Atrial fibrillation-HR-variable=p-p-Irregular

5. (Junctional)-(AV-Node)
1-Junctional Rhythum-HR-40-60/M
2-Juctional escape-HR-40-60/M
3-Premature Contraction
4-Accelarated Junctional Rhythum-HR-60-
100
5-Juntional Tachycardia-HR-100-180/M

6. BUNDLE OF HIS/RT & LF BRANCHES/
Parkinje Fibers/ VENTRICULAR
RHYTHUM
1-Ventricular Rhythum-HR-20-40/M
2-Ventricular Muscle-HR-10-20/M
3-Primary Ventricular Standstill-No QRS-P.wave present
4-Asystole-straight line
5-Idiopathic Ventricular-hr-20-40/M
6-Ventricular tachycardia- HR-150-250/M
7-Ventricular Flutter-HR-250-300/M
8-Ventricular Fibrillation-HR-NA

7. Heart Blocks
FIRST DEGREE HEART BLOCK
RATE-NORMAL=P-R INTERVAL(N-0.12 0.20/SEC=0.20/SEC
2ND DEGREE HEART BLOCK (Mobitz Type I (Wenckebach)
PROGRESSIVE P-R PROLONGATION-TILL 01 BEAT DROP
2ND DEGREE HEART BLOCK (Mobitz Type 2)
P-R NORMAL=2,3,4 P.waves before each QRS-HR-60-100/M
3RD DEGREE HEART BLOCK
P AND QRS NAS ITS OWN RATE-HR-30-60/M

8. Conduction System
– The heart has a conduction system
separate from any other system
– The conduction system makes up the
PQRST complex we see on paper
– An arrhythmia is a disruption of the
conduction system
– Understanding how the
heart conducts normally is
essential in understanding
and identifying arrhythmias

9. • SA Node
• Inter-nodal and
inter-atrial pathways
• A-V Node
• Bundle of His
• Purkinje Fibers
Conduction System

10. SA Node
 The primary pacemaker
of the heart
 Each normal beat is
initiated by the SA node
 Inherent rate of 60-100
beats per minute
 Represents the P-wave
in the QRS complex or
atrial depolarization
(firing)

11. AV Node
– Located in the septum of
the heart
– Receives impulse from
inter-nodal pathways
and holds the signal
before sending on to the
Bundle of His
– Represents the PR
segment of the QRS
complex

12. AV Node
– Represents the PR segment of the cardiac
cycle
– Has an inherent rate of 40-60 beats per
minute
– Acts as a back up when the SA node fails
– Where all junctional rhythms originate

13. QRS Complex
• Represents the
ventricles
depolarizing (firing)
collectively. (Bundle
of His and Purkinje
fibers)
• Origin of all
ventricular rhythms
• Has an inherent rate
of 20-40 beats per
minute

14. ECG Trace
• Isoelectric
line
(baseline)
• P-wave
– Atria firing
• PR interval
– Delay at AV

15. ECG Trace
• QRS
– Ventricles
firing
• T-wave
– Ventricles
repolarizing

16. ECG Trace
• ST segment
– Ventricle
contracting
– Should be at
isoelectric line
– Elevation or
depression may
be important
• U wave
– Perkinje fiber
repolarization?

17. ECG- Analysis
1) RATE
2) RHYTHUM
3) AXIS
4) WAVE FORM

18. ECG-PAPER

19. 1-RATE
Calculation
 300,150,100
75,60,50
1-What is the rate?
• Count the number of beats occurring in one minute
• Counting the p-waves will give the atrial rate
• Counting QRS will give ventricular rate

20. 2-RHYTHUM
2-Is the rhythm regular?
• Verify by assessing R-R interval
• Confirm by assessing P-P interval

21. 3-axis
LEADS- I, AVF
REULE OF THUMB
1- I,AVF= R ,UP= Normal axis
2- 1,AVF= R,WAVE DOWN =Extreme
T-RT. Axis deviation
3- I -R=UP,
AVF-R=DOWN =LT.Axis. Deviation
4-1,R =down.
AVF,R=UP=RT. Axis deviation

22. Determining the Axis
Predominantly
Positive
Predominantly
Negative
Equiphasic

23. Waveform Analysis
Is there a P-wave for every QRS?
• P-waves are upright and uniform
• One P-wave preceding each QRS

24. Calculation
 300,150,100
75,60,50
• Normal
Heart rate = 60 – 100 BPM
SA Node discharge = 60 – 100 / min
AV Node discharge = 40 – 60 min
Ventricular Tissue discharge = 20 – 40/min
PR interval = 0.12 – 0.20 sec
QRS interval= <0.12
Summary

25. • Cardiac cycle
P wave = atrial depolarization
PR interval = pause between atrial and
ventricular depolarization
QRS = ventricular Depolarization
T wave = ventricular Repolarization
Summary

26. Normal Sinus Rhythm
Heart
Rate
(bpm)
Rhythm P Wave
PR Interval
(sec)
QRS
(sec)
60 -
100
Regular
Before each QRS,
Identical
0.12 - 0.20 <0.12
Sinus Rhythms

27. • Normal Sinus Rhythm
– Sinus Node is the primary pacemaker
– One upright uniform p-wave for every QRS
– Rhythm is regular
– Rate is between 60-100 beats per minute
Sinus Rhythms

28. Sinus Bradycardia
Heart
Rate
(bpm)
Rhythm P Wave
PR Interval
(sec)
QRS
(sec)
<60 Regular
Before each QRS,
Identical
0.12 - 0.20 <0.12
Sinus Rhythms

29. • Sinus Bradycardia
– One upright uniform p-wave for every QRS
– Rhythm is regular
– Rate less than 60 beats per minute
• SA node firing slower than normal
• Normal for many individuals
• Identify what is normal heart rate for patient
Sinus Rhythms

30. •
Sinus Tachycardia
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
>100 Regular
Before each QRS,
Identical
.12 - .20 <.12
Sinus Rhythms

31. • Sinus Tachycardia
– One upright uniform p-wave for every QRS
– Rhythm is regular
– Rate is greater than 100 beats per minute
• Usually between 100-160 (>160 SVT)
• Can be high due to anxiety, stress, fever,
medications (anything that increases oxygen
consumption)
Sinus Rhythms

32. Sinus Arrhythmia
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
Var. Irregular
Before each QRS,
Identical
.12 - .20 <.12
Sinus Rhythms

33. • Sinus Arrhythmia
– One upright uniform p-wave for every QRS
– Rhythm is irregular
• Rate increases as the patient breathes in
• Rate decreases as the patient breathes out
– Rate is usually 60-100 (may be slower)
– Variation of normal, not life threatening
Sinus Rhythms

34. Sinus Arrest
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
NA Irregular
Before each QRS,
Identical
.12 - .20 <.12
Sinus Rhythms

36. Sinus Arrest
Sinus Rhythms
Stop of sinus rhythm
New rhythm starts

37. Sinus Pause
Sinus Rhythms
• One dropped beat is a
sinus pause
• Beats walk through

38. Premature Atrial Contraction (PAC)
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
NA Irregular
Premature &
abnormal or
hidden
.12 - .20 <.12
Atrial Rhythms

40. – Premature Atrial Contraction (PAC)
• One P-wave for every QRS
– P-wave may have different morphology on ectopic
beat, but it will be present
• Single ectopic beat will disrupt regularity of
underlying rhythm
• Rate will depend on underlying rhythm
• Underlying rhythm must be identified
• Classified as rare, occasional, or frequent
PAC’s based on frequency
Atrial Rhythms

41. Atrial Fibrillation
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
Var. Irregular Wavy irregular NA <.12
Atrial Rhythms

43. • Atrial Fibrillation
– No discernable p-waves preceding the QRS
complex
• The atria are not depolarizing effectively, but fibrillating
– Rhythm is grossly irregular
– If the heart rate is <100 it is considered controlled
a-fib, if >100 it is considered to have a “rapid
ventricular response”
– AV node acts as a “filter”, blocking out most of the
impulses sent by the atria in an attempt to control
the heart rate
Atrial Rhythms

44. • Atrial Fibrillation (con’t)
– Often a chronic condition, medical attention
only necessary if patient becomes
symptomatic
– Patient will report history of atrial
fibrillation.
Atrial Rhythms

45. Atrial Flutter
Heart Rate Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
Atrial=250
– 400
Ventricular
Var.
Irregular Sawtooth
Not
Measur-
able
<.12
Atrial Rhythms

46. • Atrial Flutter
– More than one p-wave for every QRS complex
• Demonstrate a “saw tooth” appearance
– Atrial rhythm is regular. Ventricular rhythm will be
regular if the AV node conducts consistently. If the
pattern varies, the ventricular rate will be irregular
– Rate will depend on the ratio of impulses
conducted through the ventricles
Atrial Rhythms

47. Atrial Rhythms
• Atrial Flutter
– Atrial flutter is classified as a ratio of p-
waves per QRS complexes (ex: 3:1 flutter
3 p-waves for each QRS)
– Not considered life threatening, consult
physician is patient symptomatic

49. • Rhythms that originate at the AV
junction
• Junctional rhythms do not have
characteristic p-waves.
Junctional Rhythms

51. Premature Junctional Contraction PJC
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
Usually
normal
Irregular
Premature,
abnormal, may be
inverted or hidden
Short
<.12
Normal
<.12
Junctional Rhythms

52. • Premature Junctional Contraction (PJC)
– P-wave can come before or after the QRS
complex, or it may lost in the QRS complex
• If visible, the p-wave will be inverted
– Rhythm will be irregular due to single ectopic beat
– Heart rate will depend on underlying rhythm
– Underlying rhythm must be identified
– Classify as rare, occasional, or frequent PJC
based on frequency
– Atria are depolarized via retrograde conduction
Junctional Rhythms

53. Junctional Rhythms

54. Accelerated Junctional
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
Var. Regular
Inverted, absent or
after QRS
<.12 <.12
Junctional Rhythms

55. • Accelerated Junctional Rhythm
– P-wave can come before or after the QRS
complex, or lost within the QRS complex
• If p-waves are seen they will be inverted
– Rhythm is regular
– Heart rate between 60-100 beats per
minute
• Within the normal HR range
• Fast rate for the junction (normally 40-60 bpm)
Junctional Rhythms

56. Junctional Rhythms

57. Junctional Tachycardia
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
>100 Regular
May be inverted or
hidden
Short
<.12
Normal
<.12
Junctional Rhythms

58. • Junctional Tachycardia
– P-wave can come before or after the QRS
complex or lost within the QRS entirely
• If a p-wave is seen it will be inverted
– Rhythm is regular
– Rate is between 100-180 beats per minute
• In the tachycardia range, but not originating from SA
node
– AV node has spread up to override the SA node
for control of the heart
Junctional Rhythms

59. Junctional Rhythms

60. Junctional Rhythms
Junctional Escape
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
40 –
60
Regular
Absent, inverted
or after QRS
Short
<.12
Normal
<.12

61. Junctional Rhythms
• Junctional Escape Rhythm
– P-wave may come before or after the QRS
or may be hidden in the QRS entirely
• If p-waves are seen, they will be inverted
– Rhythm is regular
– Rate 40-60 beats per minute
• The SA node has failed; the AV junction takes
over control of the heart

62. Junctional Rhythms

63. Ventricular Rhythms
Premature Ventricular Contraction (PVC)
Heart
Rate
Rhythm P Wave
PR
Interval
(sec.)
QRS
(Sec.)
Var. Irregular
No P waves
associated with
premature beat
NA
Wide
>.12

64. Ventricular Rhythms
• Premature Ventricular Contraction (PVC)
– The ectopic beat is not preceded by a p-wave
– Irregular rhythm due to ectopic beat
– Rate will be determined by the underlying rhythm
– QRS is wide and may be bizarre in appearance
– Caused by a irritable focus within the ventricle
which fires prematurely
– Must identify an underlying rhythm

65. Ventricular Rhythm
• Premature Ventricular Contraction
– Classify as rare, occasional, or frequent
– Classify as unifocal, or multifocal PVC’s
• Unifocal-originating from same area of the
ventricle; distinguished by same morphology

66. Ventricular Rhythm
• Premature Ventricular Contraction
– Classify as unifocal or multifocal PVC’s
– Unifocal-originating from same area of the
ventricle; distinguished by same morphology
– Multifocal-originating from different areas of the
ventricle; distinguished by different morphology

67. Ventricular Rhythm
Multifocal-originating from different areas of the
ventricle; distinguished by different morphology

68. Ventricular Rhythm
• Premature Ventricular Contraction
– Bigeminy
• A PVC occurring every other beat
– Also seen as Trigeminy, Quadrigeminy

72. Ventricular Rhythm
• Dangerous PVC’s
– R on T
– Runs of PVC’s
– 3 or more
considered Vtach

74. Idioventricular Rhythm
Ventricular Rhythm

75. Ventricular Rhythm

76. Ventricular Rhythms
Ventricular Flutter
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
150 –
300
Regular No P waves NA
Wide
>.12

77. Ventricular Rhythms
Ventricular Flutter
“Extreme V-Tach”
Call code
Begin CPR

78. Ventricular Rhythms
Ventricular Flutter
“Extreme V-Tach”
Call code
Begin CPR

79. Ventricular Rhythms
Ventricular Tachycardia
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
100 –
250
Regular
No P waves
corresponding to QRS,
a few may be seen
NA >.12

80. Ventricular Rhythms
• Ventricular Tachycardia
– No discernable p-waves with QRS
– Rhythm is regular
– Atrial rate cannot be determined,
ventricular rate is between 150-250 beats
per minute
– Must see 4 beats in a row to classify as v-
tach

81. Ventricular Rhythms
• Ventricular
Tachycardia
– THIS IS A DEADLY
RHYTHM
• Check patient:
– If patient awake
and alert, monitor
patient and call
physician
– If patient has no
vital signs, call
code and start CPR
» Defibrillate

82. Ventricular Rhythms
Ventricular Fibrillation
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
0 Chaotic None NA None

83. Ventricular Rhythms
• Ventricular Fibrillation
– No discernable p-waves
– No regularity
– Unable to determine rate
– Multiple irritable foci within the ventricles all
firing simultaneously
– May be coarse or fine
– This is a deadly rhythm
• Patient will have no pulse
• Call a code and begin CPR

84. Ventricular Rhythms

85. Asystole
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
None None None None None

86. Asystole
• No p-waves
• No regularity
• No Rate
• This rhythm is associated with death
– Check patient and leads
– No pulse
• Begin CPR

87. Heart Block
First Degree Heart Block
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.)
Norm. Regular
Before each QRS,
Identical
> .20 <.12

88. Heart Block
– First Degree Heart Block
• P-wave for every QRS
• Rhythm is regular
• Rate may vary
• Av Node hold each impulse longer than normal
before conducting normally through the
ventricles
• Prolonged PR interval
– Looks just like normal sinus rhythm

89. Heart Block

90. Heart Block
Second Degree Heart Block
Mobitz Type I (Wenckebach)
Heart
Rate
Rhythm P Wave
PR Interval
(sec.)
QRS
(Sec.
)
Norm.
can be
slow
Irregular
Present but some
not followed by
QRS
Progressively
longer
<.12

91. Heart Block
• Second Degree Heart Block
• Mobitz Type I (Wenckebach)
– Some p-waves are not followed by QRS
complexes
– Rhythm is irregular
• R-R interval is in a pattern of grouped beating
– Rate 60-100 bpm
– Intermittent Block at the AV Node
• Progressively prolonged p-r interval until a QRS is
blocked completely

92. Heart Block

93. Heart Block
Second Degree Heart Block
Mobitz Type II (Classical)
Heart
Rate
Rhythm P Wave
PR
Interval
(sec.)
QRS
(Sec.)
Usually
slow
Regular
or
irregular
2 3 or 4 before each
QRS, Identical
.12 - .20
<.12
depends

94. Heart Block
• Second Degree Heart Block
• Mobitz Type II (Classical)
– More p-waves than QRS complexes
– Rhythm is irregular
– Atrial rate 60-100 bpm; Ventricular rate 30-100
bpm (depending on the ratio on conduction)
– Intermittent block at the AV node
• AV node normally conducts some beats while blocking
others

95. Heart Block

96. Heart Block
Third Degree Heart Block
(Complete)
Heart
Rate
Rhythm P Wave
PR
Interval
(sec.)
QRS
(Sec.)
30 –
60
Regular
Present but no
correlation to QRS
may be hidden
Varies
<.12
depends

97. Heart Block
• Third Degree Heart Block (Complete)
– There are more p-waves than QRS
complexes
– Both P-P and R-R intervals are regular
– Atrial rate within normal range; Ventricular
rate between 20-60 bpm
– The block at the AV node is complete
• There is no relationship between the p-waves
and QRS complexes

98. Heart Block

101. ECG-READING
1-RATE
2-RYTHEM
3-AXIS-1,AVF
4-LEADS
V1-V2=RT.CHEST LEADS
V3-V4=SEPTAL LEADS
V1-V4=ANTERIOR CHEST LEADS
V5-V6=LATERAL CHEST LEADS
1,AVL,V1-V6=ANTROLATERAL CHEST LEADS
11,111,AVF-INFERIOR LEADS

102. 5-MYOCARDIAL INFARCTION
ANTERIOR,ANTROLATRAL,INFERIOR
ACUTE MI-T-INVERSION, ST-
ELEVATION
6-CONDUCTIONS DEFECTS
RBBB-T.WAVE-V1-V2=M-PATTERN
RBBB V5 V6 W PATTERN
LBBB-T.WAVE-V5-V6=M-PATTERN
LBBB V1 V2 W PATTERN

103. 7-CCF,PERICARDIAL EFFUSION,OBESE-
LOW VOLTAGE ECG.