The rhythm is best analyzed by looking at a rhythm strip. On a 12 lead ECG this is usually a 10 second recording from Lead II. Confirm or corroborate any findings in this lead by checking the other leads. A longer rhythm strip, recorded perhaps recorded at a slower speed, may be helpful.

1. Fundamentals of ECG
Abnormal ECG Rhythm
Dr. Md.Toufiqur Rahman
MBBS, FCPS, MD, FACC, FESC, FRCP, FSCAI,
FCCP,FAPSC, FAPSIC, FAHA,FACP
Professor & head of Cardiology
CMMC, Manikganj
Ex professor of cardiology,
NICVD, Dhaka
drtoufiq1971@gmail.comUndergraduate version

2. • The rhythm is best analyzed by looking at a rhythm
strip.
• On a 12 lead ECG this is usually a 10 second
recording from Lead II.
• Confirm or corroborate any findings in this lead by
checking the other leads.
• A longer rhythm strip, recorded perhaps recorded
at a slower speed, may be helpful.
Fundamentals of ECG
ECG Rhythm analysis

3. Fundamentals of ECG
What are the criteria for normal sinus rhythm?
 Normal P wave morphology
 P wave (atrial contraction) precedes every QRS complex
 The rhythm is regular, but varies slightly during
respirations
 The rate ranges between 60 and 100 beats per minute
 The P waves maximum height at 2.5 mm in II and/or III
 The P wave is positive in I and II, and biphasic in V1

4. 7 step approach to ECG rhythm analysis
1. Rate
Tachycardia or bradycardia?
Normal rate is 60-100/min.
2. Pattern of QRS complexes
Regular or irregular?
If irregular is it regularly irregular or irregularly irregular?
3. QRS morphology
Narrow complex: sinus, atrial or junctional origin.
Wide complex: ventricular origin, or supraventricular with aberrant conduction.
4. P waves
Absent: sinus arrest, atrial fibrillation
Present: morphology and PR interval may suggest sinus, atrial, junctional or even
retrograde from the ventricles.
Fundamentals of ECG
What are the steps to ECG rhythm analysis?

5. 5. Relationship between P waves and QRS complexes
AV association (may be difficult to distinguish from isorhythmic dissociation)
AV dissociation
complete: atrial and ventricular activity is always independent.
incomplete: intermittent capture.
6. Onset and termination
Abrupt: suggests re-entrant process.
Gradual: suggests increased automaticity.
7. Response to vagal manoeuvres
Sinus tachycardia, ectopic atrial tachydysrhythmia: gradual slowing during the vagal
manoeuvre, but resumes on cessation.
AVNRT or AVRT: abrupt termination or no response.
Atrial fibrillation and atrial flutter: gradual slowing during the manoeuvre.
Fundamentals of ECG
What are the steps to ECG rhythm analysis?
7 step approach to ECG rhythm analysis

6. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-1: A 23
years old
medical student
presented with
palpitations
and occasional
chest
discomfort. He
had the
following ECG.

7. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-2: A 51
years old lady
presented with
palpitations,
excessive
sweating ,
weight loss and
chest
discomfort on
exertion. She
had the
following ECG.

8. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-3: A 34
years old lady
presented with
palpitations ,
shortness of
breath and
excessive
sweating. Her
BP was 70/50
mm Hg. She had
the following
ECG.

9. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-4: A 65 years old
gentleman presented
with chest tightness,
shortness of breath
and palpitations for
last 45 minutes. He is
hypertensive, smoker
and diabetic. On
emergency
department his BP-
70/ 40 mm Hg and he
had the following ECG.

10. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-5: A 45 years old
gentleman presented with
severe chest pain with
excessive sweating for last 1
hour and he was diagnosed as
a case of acute anterior
myocardial infarction in
emergency department and
BP was 120/80 mm Hg and
was admitted to CCU , while
shifting to CCU he suddenly
collapsed and on reaching
CCU he was found no
palpable pulse, no recordable
BP and he had the following
ECG. He was given DC shock
and reverted to sinus rhythm.
.

11. Fundamentals of ECG
What are the causes of Narrow Complex
(Supraventricular) Tachycardia?
ATRIAL – REGULAR
Sinus tachycardia
Atrial tachycardia
Atrial flutter
Inappropriate sinus tachycardia
Sinus node re-entrant tachycardia
ATRIAL – IRREGULAR
Atrial fibrillation
Atrial flutter with variable block
Multifocal atrial tachycardia
ATRIOVENTRICULAR
Atrioventricular re-entry tachycardia (AVRT)
AV nodal re-entry tachycardia (AVNRT)
Automatic junctional tachycardia

12. Fundamentals of ECG
What are the causes of Broad complex Tachycardia(BCT) ?
REGULAR BCT
 Ventricular tachycardia
 Antidromic atrioventricular re-entry tachycardia (AVRT).
 Any regular supraventricular tachycardia with aberrant
conduction — e.g. due to bundle branch block, rate-related
aberrancy.
IRREGULAR
 Ventricular fibrillation
 Polymorphic VT
 Torsades de Pointes
 AF with Wolff-Parkinson-White syndrome
 Any irregular supraventricular tachycardia with aberrant conduction
— e.g. due to bundle branch block, rate-related aberrancy.

13. Fundamentals of ECG
How to approach to a patient with Bradycardia?
P WAVES PRESENT
1. Every P wave is followed by a QRS complex (= sinus node
dysfunction)
Sinus bradycardia, Sinus node exit block, Sinus pause / arrest
2. Not every P wave is followed by a QRS complex (= AV node
dysfunction)
AV block: 2nd degree, Mobitz I (Wenckebach)
AV block: 2nd degree, Mobitz II (Hay)
AV block: 2nd degree, “fixed ratio blocks” (2:1, 3:1)
AV block: 2nd degree, “high grade AV block”
AV block: 3rd degree (complete heart block)
P WAVES ABSENT
Narrow complex: Junctional escape rhythm
Broad complex: Ventricular escape rhythm

14. Fundamentals of ECG
Some arrhythmias with characteristic findings
Absent P waves with "irregularly irregular"
QRS complexes is the hallmark of atrial
fibrillation.
A "saw tooth" pattern with QRS complexes is
the hallmark of atrial flutter.
A sine wave pattern is the hallmark
of ventricular flutter.
Absent P waves with wide QRS complexes and
a fast heart rate is ventricular tachycardia.

15. Fundamentals of ECG
Normal findings in healthy individuals
 Tall R waves
 Prominent U waves
 ST segment elevation (high-take off, benign
early repolarisation)
 Exaggerated sinus arrhythmia
 Sinus bradycardia
 Wandering atrial pacemaker
 Wenckebach phenomenon
 Junctional rhythm
 1st degree heart block

16. Fundamentals of ECG
Different types of Arrhythmia
Supraventricular arrhythmia
Premature atrial complexes
Premature junctional complexes
Atrial fibrillation
Atrial flutter
Ectopic atrial tachycardia and rhythm
Multifocal atrial tachycardia
Paroxysmal supraventricular tachycardia
Junctional rhythms and tachycardias

17. Fundamentals of ECG
Different types of Arrhythmia
Ventricular arrhythmia
Premature ventricular complexes (PVCs)
 ventricular ectopyics
Ventricular tachycardia
Accelerated ventricular rhythms
Idioventricular rhythm
Ventricular Parasystole

18. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-1: A 23 years
old medical student
presented with
palpitations and
occasional chest
discomfort. He had
the following ECG.
Figure: ECG showing narrow complex tachycardia (sinus
tachycardia) ( Heart rate-108bpm, rhythm –regular. Each
QRS complex following P wave).

19. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-2: A 51 years
old lady presented
with palpitations,
excessive sweating
, weight loss and
chest discomfort on
exertion. She had
the following ECG.
Figure: ECG showing Atrial fibrillation with fast ventricular
rate ( narrow complex tachycardia) , ( Ventricular rate
160bpm, rhythm irregular, no p wave)

20. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-3: A 34 years
old lady presented
with palpitations ,
shortness of breath
and excessive
sweating. Her BP was
70/50 mm Hg. She
had the following
ECG.
Figure: ECG showing Supraventricular
tachycardia( Narrow complex tachycardia)(
Rate-225bpm, rhythm- regular)

21. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-4: A 65 years old
gentleman presented with
chest tightness, shortness of
breath and palpitations for
last 45 minutes. He is
hypertensive, smoker and
diabetic. On emergency
department his BP-70/ 40 mm
Hg and he had the following
ECG.
Figure: ECG showing Ventricular tachycardia( wide
complex tachycardia). ( ventricular rate-250 bpm,
rhythm-regular , QRS complex-wide)

22. Fundamentals of ECG
What are the steps to ECG rhythm analysis?
Case-5: a 45 years old gentleman presented
with severe chest pain with excessive
sweating for last 1 hour and he was
diagnosed as a case of acute anterior
myocardial infarction in emergency
department and BP was 120/80 mm Hg and
was admitted to CCU , while shifting to CCU
he suddenly collapsed and on reaching CCU
he was found no palpable pulse, no
recordable BP and he had the following ECG.
He was given DC shock and reverted to sinus
rhythm.
.
Figure: ECG showing Ventricular fibrillation(
Wide complex tachycardia, rhythm- irregular)