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1. ECG BASICSECG BASICS
55thth
LectureLecture
Supraventricular arrhythmias
By
Salah Mabruok Khalaf
South Egypt Cancer Institute
2017
Course of Medical Oncology
Medical Oncology department

2. Introduction to ECG Rhythm Analysis
• The analysis should begin with identifying
three categories
1. Impulse origin
2. Rate
3. Regularity

3. Introduction to ECG Rhythm Analysis
1- impulse origin
(i.e., where is the abnormal rhythm coming from?)
 Sinus Node (e.g., sinus tachycardia)
 Atria (e.g., PAC)
 AV junction (e.g., junctional escape rhythm)
 Ventricles (e.g., PVC)

4. Introduction to ECG Rhythm Analysis
2-Rate
(i.e., relative to the "expected rate" for that pacemaker location)
o Accelerated - faster than expected (e.g., accelerated junctional
rhythm @ 75bpm)
o Slower than expected (e.g., marked sinus bradycardia @ 40bpm)
o Normal (e.g., junctional escape rhythm)
o N.B. expected rate SA Node 60 - 100 beats/minute.
AV Node 40 - 60 beats/minute.
Ventricular cells 20 - 45 bpm.

5. Calculate Rate
• Option 1( for regular and irregular
rhythm)
– Count the # of R waves in a 6 second
rhythm strip, then multiply by 10.
Interpretation?
7 x 10 = 70 bpm

6. Calculate Rate
• Option 1( for regular and irregular
rhythm)
– Count the # of R waves in a 6 second
rhythm strip, then multiply by 10.
Interpretation?
5 x 10 = 50 bpm

7. Option 2 (for regular rhythm)
– Find a R wave that lands on a bold line.
– Count the # of large boxes to the next R
wave. Then calculate the rate from this
equation
• OR HR=----------------------------------------
R wave
No of Large squares in RR interval
300

8. • Option 2 (cont)
– Memorize the sequence:
300 - 150 - 100 - 75 - 60 - 50
Interpretation?
3
0
0
1
5
0
1
0
0
7
5
6
0
5
0
Approx. 1 box less
than 100 = 95 bpm

9. Option 2 (for regular rhythm) more accurate
– Find a R wave that lands on a bold line.
– Count the # of large boxes to the next R
wave. Then calculate the rate from this
equation
• OR HR=----------------------------------------
No of small squares in RR interval
1500
In this ECG HR = 1500/16 = 93

10. 3-Regularity of ventricular or atrial
response
• Look at the R-R distances (using a caliper or
markings on a pen or paper).
• Regular (are they equidistant apart)?
Occasionally irregular? Regularly irregular?
Irregularly irregular?
Regular (e.g., PSVT)
Regular irregularity (e.g., ventricular bigeminy)
Irregular irregularity (e.g., atrial fibrillation or MAT)
R R

11. Supraventricular arrhythmias
1.Sinus Bradycardia
2.Sinus Tachycardia
3.Sinus arrhythmia
4.Sinus node dysfunction(SND)
5.Premature atrial complexes and atrial bigeminy
6.Premature junctional complexes
7.Atrial fibrillation
8.Atrial flutter
9.Ectopic atrial tachycardia and rhythm
10.Multifocal atrial tachycardia
11.Wandering Pacemaker
12.Paroxysmal supraventricular tachycardia
13.Junctional Escape Beat
14.Junctional Escape rhythm
15.Accelerated Junctional Rhythm
16.Junctional Bradycardia
17.Junctional tachycardia

12. Supraventricular Arrhythmias
1. Sinus Bradycardia
<60 bpm =30• Rate?
• Regularity? regular
normal
0.10 s
• P waves?
• PR interval? 0.12 s
• QRS duration?
Interpretation? Sinus Bradycardia

13. • Causes of Bradycardia
• A- Intrinsic Causes
• Idiopathic degeneration (aging)
• Infarction or ischemia
• Infiltrative diseases
– Sarcoidosis
– Amyloidosis
– Hemochromatosis
• Infectious diseases
– Chagas' disease
– Endocarditus
• Immune diseases
– Systemic lupus erythematosis.
– Rheumatoid arthritis
– Scleraderma.
• Iatrogenic trauma
– Valve replacement
– Correction of congenital heart disease
– Heart transplantation .

14. • Extrinsic Causes
• Autonomically mediated syndromes (i.e. vomiting,
sleeping, etc.)
– Carotid-sinus hypersensitivity: from vagus innervation
hypertonicity
– Neurocardiac syncope
– Situational disturbances: coughing, micturition, defecation,
vomiting
• Drugs
– Antiarrhythmic agents: pronestyl, quinidine, etc.
– B-Adrenergic blockers.
– Calcium-channel blockers:
– Digoxin
• Hypothyroidism
• Hypothermia
• Hypokalemia
• Hyperkalemia:

15. 2. Sinus Tachycardia
>100 bpm =130• Rate?
• Regularity? regular
normal
0.08 s
• P waves?
• PR interval? 0.16 s
• QRS duration?
Interpretation? Sinus Tachycardia

16. Causes of Sinus Tachycardia
• Thyrotoxicosis
• Anemia
• Anxiety
• Coronary ischemia and myocardial infarction , failure
• Chronic pulmonary disease
• Caffeine, nicotine, cocaine, or amphetamines
• Hyperthermia
• Hyperdynamic circulation
• Hypovolemia with hypotension and shock
• Hypoxia
• Pheochromocytoma
• Pulmonary embolism

17. • 3- Sinus Arrhythmia
• Respiratory sinus arrhythmia
• The rate usually increases with inspiration and decreases with
expiration.
• This rhythm is most commonly seen with breathing due to fluctuations
in parasympathetic vagal tone.

18. • Non respiratory sinus arrhythmia
• Ventriculophasic sinus arrhythmia is a non-respiratory
sinus arrhythmia seen in complete AV block.
• The PP interval enclosing a QRS complex is shorter than
a PP interval not enclosing a QRS.

19. 4-Sinus node dysfunction(SND)
Sinus pause
Sinus arrest
Sinus block
• First degree SA block can not be diagnosed by
surface ECG.
• Second degree SA block is usually diagnosed
when the sinus pause is in the multiples of
resting sinus cycles.
• Third degree SA block is same as sinus arrest
and subsidiary pacemaker will function in these
patients.
• If the pauses are not in exact multiples, sinus
arrest is diagnosed.

20. Sinus pause
• When sinus cycle length exceeds 15 %
of the previous sinus cycle it is referred to
as sinus pause.

21. Sinus pause

22. 2nd
degree SAN block
Electrocardiogram: Sinoatrial Exit Block

23. 2nd
degree SAN block

24. Sinus arrest
= 3rd
degree SAN block
Pauses in excess of three seconds.
• The following example shows a delay between beats of
over four seconds. The RR interval is highlighted.
Electrocardiogram: Sinus Arrest

25. 5. Premature atrial complexes
• Occur as single or repetitive events and have unifocal or
multifocal origins.
• The ectopic P wave (called P') is often hidden in the ST-T
wave of the preceding beat "Search for the P on the T
wave“
• The P'R interval is normal or prolonged because the AV
junction is often partially refractory when the premature
impulse enters it.
• ECG.
The compensatory pause after a PAC is usually incomplete

26. Atrial Bigeminy
• Each normal beat is followed by an
atrial premature beat

27. Sinus Rhythm with Atrial Bigeminy.

28. Atrial Trigeminy
• For each 2 normal beat is followed by
an atrial premature beat
• If every third beat in an ECG rhythm strip
is a PAC

29. Atrial quadrigeminy
• For each 3 normal beat is followed
by an atrial premature beat

30. Atrial Parasystole
PACs, shown by arrows, occur at a common inter-
ectopic interval or at multiples of this interval.

31. Atrial Parasystole

32. • Non-Conducted or Blocked Premature
Atrial Contractions (PAC's)

33. 6-Atrial Escape Beats
• Must have the following qualities:
1. They must occur at the end of a pause.
2. They must have a 'P' wave that is a different shape than
the sinus 'P' waves.
3. They must have a 'PR' interval that is at least .12 s (3
small squares) or more in length.
4. The 'QRS' complex of the escape beat must be the same
shape and size as the other sinus 'QRS' complexes.
Note difference between atrial escape rhythm and atrial premature complexes is
the site of compensatory pause (before abnormal impulse in AEB and after
abnormal beat in PACs

34. 6.Premature junctional complexes
• Similar to PAC's in clinical implications, but occur less
frequently.
• The PJC focus, located in the AV junction, captures the atria
(retrograde) and the ventricles (antegrade).
• The retrograde P wave may appear before, during, or after
the QRS complex; if before, the PR interval is usually short
(i.e., <0.12 s).

35. P
P
NO P
Conditions of AV nodal impulse
1-AVN give atrium before ventricle
Inverted P wave then QRS
2-AVN give ventricle before atrium
QRS then Inverted P wave QRS
3-AVN give atrium and ventricle at same time
P wave masked in QRS( absent P)
av
II

36. Premature Junctional Contraction (PJC)
P

37. 7. Atrial Fibrillation (AF)
• Atrial activity is poorly defined; may see
course or fine undulations (fibrillation) or no
atrial activity at all. If atrial activity is seen, it
resembles an old saw (when compared to
atrial flutter that often resembles a new saw).
• Ventricular response is irregularly irregular
and may be fast (HR >100 bpm), moderate
(HR = 60-100 bpm), or slow (HR <60 bpm,
indicates excessive rate control, AV node
disease, or drug toxicity).

38. • Atrial Fibrillation With Moderate Ventricular Response

39. Atrial Fibrillation (AF(
• When regular??
• regular ventricular response in complete AV
block with an escape or accelerated ectopic
pacemaker originating in the AV junction or
ventricles (i.e., must consider digoxin
toxicity or AV node disease).
• The differential diagnosis includes atrial
flutter with an irregular ventricular response
and multifocal atrial tachycardia (MAT),
which is usually irregularly irregular.

40. Atrial Fibrillation (AF)

41. • When RAPID AF????
• Atrial fibrillation with rapid ventricular
response > 100 /m

42. 8- Atrial Flutter
• Regular atrial activity with a "saw-tooth appearance
in leads II, III, aVF
• The atrial rate is usually about 300-350/min.
• The flutter waves are often difficult to find when
there is 2:1 ratio. Therefore, always think "atrial
flutter with 2:1 block" whenever there is a regular
supraventricular tachycardia @ ~150 bpm! (You
won't miss it if you look for it in a 12-lead ECG)
• The ventricular response may be 2:1, 3:1 (rare), 4:1,
or irregular depending upon the AV conduction
properties and AV node slowing drugs on board
(e.g., digoxin, beta blockers).

43. Atrial Flutter

44. Atrial flutter with variable ventricular
response
• The saw-tooth flutter waves together with some regularity in
its pattern give this ECG rhythm away. Note that the flutter
waves occur at a rate close to 300/minute. The R-R intervals
suggest rates of close to 100/miute (3:1 ventricular response),
then 75/minute (4:1 ventricular response) and later a rate of
60/minute (5:1 response). The atrial flutter is presenting with
variable AV blocking resulting in variable ventricular response.

45. The tracing shows atrial flutter with variable block and atrial rate 300.

46. • Atrial Flutter With Variable AV Block

47. 9. Ectopic Atrial Tachycardia and Rhythm
• Ectopic, discrete looking, unifocal P' waves with
atrial rate <250/min
• Ectopic P' waves usually precede QRS complexes
with P'R interval < RP' interval (i.e., not to be
confused with paroxysmal supraventricular
tachycardia with retrograde P waves appearing
shortly after the QRS complexes).
• Ventricular response may be 1:1 or with varying
degrees of AV block (especially in digitalis toxicity)
• Ectopic atrial rhythm is similar to ectopic atrial
tachycardia, but with HR < 100 bpm.

48. Ectopic atrial tachycardia.

49. 10. Multifocal Atrial Tachycardia (MAT)
Discrete, multifocal P' waves occurring at rates of 100-
250/min and with varying P'R intervals (should see at
least 3 different P wave morphologies in a given lead).
• Ventricular response is irregularly irregular (i.e., often
confused with A-fib).
• May be intermittent, alternating with periods of normal
sinus rhythm.

50. Multifocal Atrial Tachycardia (MAT(

51. Multifocal Atrial Tachycardia (MAT(

52. 11-Wandering atrial
Pacemaker
• A Wandering Atrial Rhythm occurs in an ECG rhythm strip
whenever three or more different ectopic sites in the atria
take over the function of the SA node and alternate to
create the electrical impulse that pace the heart and cause
the myocardium to contract.
• Wandering Atrial Pacemaker rhythm will have the following
qualities:
1. The rhythm will be slightly irregular. The distance between
'QRS' complexes will vary by one or two small squares.
2. There will be three or more different shaped 'P' waves.
3. The 'PR' interval will be at least .12 seconds in length.

53. 11- Wandering atrial Pacemaker
• A slower version of multifocal atrial tachycardia, the
narrow QRS complexes, the various P wave
configurations and an irregular rate of about 80/minute all
support this ECG rhythm to be a wandering pacemaker.
• While this rhythm is slightly irregular (this is typical of sinus
arrhythmia), the changing P waves is the most important
finding.

54. Wandering atrial Pacemaker

55. 12. Paroxysmal Supraventricular Tachycardia (PSVT)
Basic Considerations:
1. These arrhythmias are circus movement or reciprocating
tachycardia because they utilize the mechanism of reentry.
2. The onset: sudden, The offset: sudden, so-called paroxysmal
3. Usually initiated by a premature beat
4. They are usually narrow-QRS tachycardia unless there is
preexisting bundle branch block or rate-related aberrant
ventricular conduction.
5. There are several types of PSVT depending on the location of
the reentry circuit.

56. Paroxysmal Supraventricular Tachycardia
(PSVT(

57. Paroxysmal Supraventricular Tachycardia
(PSVT(

58. 13- Junctional Escape Beats:
• Must have the following qualities:
1. The abnormal beat must come at the end of a pause in
the ECG rhythm strip.
2. If the abnormal beat has a 'P' wave preceding the 'QRS'
complex, it must have a short 'PR' interval. A short 'PR'
interval is below 12 seconds (3 small boxes) in length.
3. The abnormal beat may not have a 'P' preceding it.
4. The 'QRS' complex of the beat must be the same shape
and size as all the other sinus beats in rhythm strip.

59. 14- Junctional Escape Rhythm:
This is a sequence of 3 or more junctional
escapes occurring at a rate of 40-60 bpm.
There may be AV dissociation or the atria
may be captured retrogradely by the
junctional pacemaker.

60. • Causes of Junctional escape Rhythm:
1. Healthy athlete at rest
2. Beta Blockers, Ca Channel Blockers, Dig Toxicity
3. Increased parasympathetic tone
4. Acute Inferior MI
5. Rheumatic Heart Disease
6. Post-Cardiac Surgery
7. Valvular Disease
8. SA Node Disease
9. Hypoxia

62. • This ECG rhythm could be a normal sinus rhythm except
that the narrow QRS complexes are not accompanied by
any P waves. Therefore, this rhythm that occurs at a rate
of about 60/minute originates from the AV junction.
Because this rhythm occurs at a rate characteristic of a
junctional pacemaker (40-60/minute), this ECG rhythm is
a junctional rhythm.

63. 15-Junctional bradycardia
• This rhythm originates from the AV
junction. Because this rhythm occurs at a
rate slower than the junction typically
fires (40-60/minute), this ECG rhythm is
called a junctional bradycardia.

64. 16- Accelerated Junctional Rhythm:
This is an active junctional pacemaker rhythm caused
by events that perturb pacemaker cells (e.g.,
ischemia, drugs, and electrolyte abnormalities).
The rate is 60-100 bpm

65. • The ECG rhythm includes a series of narrow QRS
complexes, inverted P waves and a rate of about
70/minute. This rhythm originates from the AV junction.
Because this rhythm occurs at rates faster than the
junction typically fires (40-60/minute) but less than a
tachycardia (100/minute), this ECG rhythm is called an
accelerated junctional rhythm.

66. 17- Nonparoxysmal Junctional Tachycardia:
This usually begins as an accelerated junctional
rhythm but the heart rate gradually increases to
>100 bpm.
There may be AV dissociation, or retrograde atrial
capture may occur.
Ischemia (usually from right coronary artery
occlusion) and digitalis intoxication are the two
most common causes.

67. • This rapid ECG rhythm includes narrow QRS complexes,
an absence of P waves prior to each QRS and a rate
faster than 100/minute. This rhythm occurs at a rate of
about 180- 190/minute.
• Notice the inverted waveform after many of the QRS
complexes – possible further evidence for junctional
tachycardia (inverted P waves).