ECG 101
Yale University School of Medicine
Section of Cardiovascular Medicine
james.revkin@yale.edu
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Basic analysis
•
•
•
•
•
•
•
Rate (fast or slow)
Rhythm (atrial, ventricular, regular, irregular)
Axis
Conduction disease (atrial or ventricular)
Hypertrophy
Ischemia, infarction
Other abnormalities (QT interval, repolarization
changes)
EKG history
Charles Einthoven
electrophysiology
ECG as an “imaging tool”
ECG as an “imaging tool”
Right side
Left side
Basic ECG
P wave
Septal Q Wave
Q R wave
repolarization
Basic ECG
Basic analysis
•
•
•
•
•
•
•
Rate (fast or slow)
Rhythm (atrial, ventricular, regular, irregular)
Axis
Conduction disease (atrial or ventricular)
Hypertrophy
Ischemia, infarction
Other abnormalities (QT interval, repolarization
changes)
Normal 12 Lead ECG
300 bpm
150 bpm
100 bpm
75 bpm
60 bpm
50 bpm
~ 45 bpm
Calculating rate of an irregular
rhythm
Count number of beats in two 3 sec intervals
( = 6 sec total) and multiply times 10
Rate approx 60 bpm
Normal Frontal Axis
Lead I
Lead aVF
Lead V1
Normal precordial Axis
Lead V6
1F
Frontal Plane Axis Calculator
1G
Precordial Axis
1H
Frontal Plane Axis Calculation
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Session 1 ECGs
1A
1B
1C
1D
1E
1I
1J
1K
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
electrophysiology
PR Interval
 PR 
A – V Block
• At level of A-V node
– 1st degree
• Prolongation of PR interval > 0.2 ms
– 2nd degree
• Mobitz Type I - Wenckebach, progressive prolongation of
PR interval, then dropped beat
• Mobitz Type II
– 3rd degree
• Complete heart block, independent atrial and ventricular
rates
QRS Interval
QRS
Ventricular (bundle branch)
blocks
• LBBB
– Hemiblocks
• Left anterior fascicular block (left anterior
hemiblock)
• Left posterior fascicular block (left posterior
hemiblock
• RBBB
LBBB
RBBB
Hemi-blocks
• Within the Left Bundle
– Hemiblocks
• Left anterior fascicular block (left anterior
hemiblock)
• Left posterior fascicular block (left posterior
hemiblock
Left anterior hemi-block
Left posterior hemi-block
Hypertrophy
• Atrial
– Left atrial hypertrophy
– Right atrial hypertrophy
• Ventricualr
– LVH
– RVH
Left Atrial Hypertrophy
Right Atrial Hypertrophy
Ventricular Hypertrophy
• RVH
– R > S in V1
– Right axis deviation
• LVD
– R wave 15 mm high in lead I
– Sum deepest S wave V1 or V2 and add to
tallest R wave in V5 or V6 > 35 mm
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Session 2 ECGs
2A
2B
2C
2D
2E
2F
2G
2H
2I
2J
2K
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Sinus arrhythmia
Non-sinus atrial rhythm
Multi-focal atrial tachycardia (MAT)
Junctional rhythm
Paroxysmal supraventricular tachycardia
PSVT
atrial flutter
atrial fibrillation
Session 3 ECGs
3A
3B
3C
3D1
3D2
3E
3F
3G
3H1
3I-1
3I-2
3I-3
3J
3K1
3K2
3L1
3L2
3M
3N
3O
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
ECG Basics
• What does the QRS complex represent?
• What should the axis of a normal QRS
complex be:
– in the frontal plane?
– in the precordial plane?
• What would make the QRS complex wide?
Assessment of WCT
• definition of wide complex tachycardia
– QRS duration greater than 0.12 seconds
– heart rate greater than 100 bpm
• differential diagnosis of WCT
– supraventricular tachycardia with:
• preexisting bundle branch block
• aberrant conduction (rate related)
• accessory pathway
– ventricular tachycardia
ECG Basics
• What does the QRS complex represent?
• What should the axis of a normal QRS
complex be:
– in the frontal plane?
– in the precordial plane?
• What would make the QRS complex wide?
Normal Frontal Axis
Lead I
Lead aVF
Lead V1
Normal precordial Axis
Lead V6
LBBB
RBBB
Stepwise Assessment of Wide Complex
Tachycardia
• Goal: develop easier more accurate criteria for
analysis.
• Applied guidelines to 554 WCT patients who’d
had previous EP studies (384 VT and 170 SVT).
• Analyze ECGs using a four step algorithm.
• Observers would stop when a positive analysis of
VT was made.
• SVT with aberrant conduction was the diagnosis
of exclusion.
Brugada P, Brugada J, et al
Circulation 1991;83:1649-1659
Stepwise Assessment of Wide Complex
Tachycardia
• Are RS complexes absent in all precordial leads?
• Does any RS interval exceed 100 msec in the
precordial leads?
• Is A-V dissociation present?
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (384 VT, 170 SVT with aberration)
• Are RS complexes absent in all precordial leads?
83 Yes
83 VT
SN = 0.21 SP = 1.0
471 No
Go to next step
Absence of precordial RS complexes
V1
V6
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (384 VT, 170 SVT with aberration)
• Are RS complexes absent in all precordial leads?
83 Yes
83 VT
SN = 0.21 SP = 1.0
471 No
Go to next step
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (83 VT, 471 unknown)
• RS Interval > 100 ms in one precordial lead?
175 Yes
172 VT 3 SVT
SN = 0.66 SP = 0.98
296 No
Go to next step
Hypothesis: prolongation of
the intrinsicoid deflection-RS interval > 0.1 sec-could be a marker for VT
RS Interval: measured from
beginning of R wave to nadir
of the S wave.
RS = 0.080
or 80 ms
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (83 VT, 471 unknown)
• RS Interval > 100 ms in one precordial lead?
175 Yes
172 VT 3 SVT
SN = 0.66 SP = 0.98
296 No
Go to next step
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (255 VT, 3 SVT, 296 unknown)
• Is AV Dissociation Present?
59 Yes
59 VT
SN = 0.82 SP = 0.98
237 No
Go to next step
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (314 VT, 3 SVT, 237 unknown)
• Are classic morphology criteria for VT
present in both V1- V2 and V6?
68 Yes
65 VT 3 SVT
SN = 0.987 SP = 0.965
169 No
164 SVT 5 VT
SN = 0.965 SP = 0.987
Classic Criteria Suggesting VT
• QRS duration > 0.14 s
• Superior QRS axis
• Morphology in precordial leads:
RBBB-like pattern
V1
V6 R/S ratio < 1
LBBB-like pattern
V1
V6 :qR
r = 30 ms
notched S wave
RS > 70 ms
Classic Criteria Suggesting SVT
• QRS duration < 0.14 s
• Normal QRS axis
• Morphology in precordial leads:
RBBB-like pattern
LBBB-like pattern
V1:
V1: triphasic
V6 R/S ratio > 1
absent or narrow R wave
no S wave notch
steep S wave descent
V6 : no Q wave
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (314 VT, 3 SVT, 237 unknown)
• Are classic morphology criteria for VT
present in both V1- V2 and V6?
68 Yes
65 VT 3 SVT
SN = 0.987 SP = 0.965
169 No
164 SVT 5 VT
SN = 0.965 SP = 0.987
Treatment of Wide Complex Tachycardia of
indeterminate etiology
• Is patient unstable?
– Immediate synchronized cardioversion
– 100, 200, 300, 360 joules
• Borderline or stable?
– amiodarone
Stepwise Assessment of Wide Complex
Tachycardia
• Are RS complexes absent in all precordial leads?
• Does any RS interval exceed 100 msec in the
precordial leads?
• Is A-V dissociation present?
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Session 4 ECGs
4A
4B
4C
4D
4E
4G1
4G2
4H1
4H2
4I1
4J
4K
4L
4M1
4M2
4M3
4N1
4N2
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
ECG Basics
• What does the QRS complex represent?
• What should the axis of a normal QRS
complex be:
– in the frontal plane?
– in the precordial plane?
• What would make the QRS complex wide?
Assessment of WCT
• definition of wide complex tachycardia
– QRS duration greater than 0.12 seconds
– heart rate greater than 100 bpm
• differential diagnosis of WCT
– supraventricular tachycardia with:
• preexisting bundle branch block
• aberrant conduction (rate related)
• accessory pathway
– ventricular tachycardia
ECG Basics
• What does the QRS complex represent?
• What should the axis of a normal QRS
complex be:
– in the frontal plane?
– in the precordial plane?
• What would make the QRS complex wide?
Normal Frontal Axis
Lead I
Lead aVF
Lead V1
Normal precordial Axis
Lead V6
LBBB
RBBB
Stepwise Assessment of Wide Complex
Tachycardia
• Goal: develop easier more accurate criteria for
analysis.
• Applied guidelines to 554 WCT patients who’d
had previous EP studies (384 VT and 170 SVT).
• Analyze ECGs using a four step algorithm.
• Observers would stop when a positive analysis of
VT was made.
• SVT with aberrant conduction was the diagnosis
of exclusion.
Brugada P, Brugada J, et al
Circulation 1991;83:1649-1659
Stepwise Assessment of Wide Complex
Tachycardia
• Are RS complexes absent in all precordial leads?
• Does any RS interval exceed 100 msec in the
precordial leads?
• Is A-V dissociation present?
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (384 VT, 170 SVT with aberration)
• Are RS complexes absent in all precordial leads?
83 Yes
83 VT
SN = 0.21 SP = 1.0
471 No
Go to next step
Absence of precordial RS complexes
V1
V6
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (384 VT, 170 SVT with aberration)
• Are RS complexes absent in all precordial leads?
83 Yes
83 VT
SN = 0.21 SP = 1.0
471 No
Go to next step
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (83 VT, 471 unknown)
• RS Interval > 100 ms in one precordial lead?
175 Yes
172 VT 3 SVT
SN = 0.66 SP = 0.98
296 No
Go to next step
Hypothesis: prolongation of
the intrinsicoid deflection-RS interval > 0.1 sec-could be a marker for VT
RS Interval: measured from
beginning of R wave to nadir
of the S wave.
RS = 0.080
or 80 ms
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (83 VT, 471 unknown)
• RS Interval > 100 ms in one precordial lead?
175 Yes
172 VT 3 SVT
SN = 0.66 SP = 0.98
296 No
Go to next step
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (255 VT, 3 SVT, 296 unknown)
• Is AV Dissociation Present?
59 Yes
59 VT
SN = 0.82 SP = 0.98
237 No
Go to next step
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (314 VT, 3 SVT, 237 unknown)
• Are classic morphology criteria for VT
present in both V1- V2 and V6?
68 Yes
65 VT 3 SVT
SN = 0.987 SP = 0.965
169 No
164 SVT 5 VT
SN = 0.965 SP = 0.987
Classic Criteria Suggesting VT
• QRS duration > 0.14 s
• Superior QRS axis
• Morphology in precordial leads:
RBBB-like pattern
V1
V6 R/S ratio < 1
LBBB-like pattern
V1
V6 :qR
r = 30 ms
notched S wave
RS > 70 ms
Classic Criteria Suggesting SVT
• QRS duration < 0.14 s
• Normal QRS axis
• Morphology in precordial leads:
RBBB-like pattern
LBBB-like pattern
V1:
V1: triphasic
V6 R/S ratio > 1
absent or narrow R wave
no S wave notch
steep S wave descent
V6 : no Q wave
Stepwise Assessment of Wide Complex
Tachycardia
N = 554 (314 VT, 3 SVT, 237 unknown)
• Are classic morphology criteria for VT
present in both V1- V2 and V6?
68 Yes
65 VT 3 SVT
SN = 0.987 SP = 0.965
169 No
164 SVT 5 VT
SN = 0.965 SP = 0.987
Treatment of Wide Complex Tachycardia of
indeterminate etiology
• Is patient unstable?
– Immediate synchronized cardioversion
– 100, 200, 300, 360 joules
• Borderline or stable?
– amiodarone
Stepwise Assessment of Wide Complex
Tachycardia
• Are RS complexes absent in all precordial leads?
• Does any RS interval exceed 100 msec in the
precordial leads?
• Is A-V dissociation present?
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Wide Complex Tachycardia
Case 1
• 66 year old retired businessman with a history of
hypertension and a subarachnoid hemorrhage
who presented with dizziness and an episode of
chest pain.
• Patient has a lipid disorder, smokes 2 packs of
cigarettes a day, and has a son with coronary
disease.
• Exam showed HR of 210 BPM, BP 70/50, resp
12/min
Case 1
Case 1
Stepwise Assessment of Wide Complex
Tachycardia: Case 1
• Are RS complexes absent in all precordial leads?
Stepwise Assessment of Wide Complex
Tachycardia: Case 1
• Does any RS interval exceed 100 msec in the
precordial leads?
Stepwise Assessment of Wide Complex
Tachycardia: Case 1
• Is A-V dissociation present?
Stepwise Assessment of Wide Complex
Tachycardia: Case 1
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Case 1
Typical RBBB
Wide Complex Tachycardia
Case 1
• Received adenosine 6 mg, 12 mg
• Received lidocaine 100 mg, then 2 mg/min,
converting briefly to NSR.
• Labs showed normal electrolytes and CK.
• Received bretylium 200 mg, then 500 mg.
• Received procainamide 1 gm, then 2 mg/min and
metoprolol
• Cardiac catheterization showed total RCA
occlusion and 90% LAD stenosis.
Case 1: normal sinus rhythm
Case 1
NSR Frontal Axis
Case 1
NSR precordial Axis
Wide Complex Tachycardia
Case 2
• 76 yr. old woman with an extensive history of
coronary artery disease presented with
palpitations.
• had CABG in 1992, recent history of cough felt to
be bronchitis, treated with amoxicillin, history of
hypothyroidism.
• Exam showed HR of 180 BPM, BP 120/100, resp
32/min
• labs: K+ 3.7; Mg2+; T4 10.3; TSH 0.05
Case 2
Case 2
Stepwise Assessment of Wide Complex
Tachycardia: Case 2
• Are RS complexes absent in all precordial leads?
Stepwise Assessment of Wide Complex
Tachycardia: Case 2
• Does any RS interval exceed 100 msec in the
precordial leads?
Stepwise Assessment of Wide Complex
Tachycardia: Case 2
• Is A-V dissociation present?
Stepwise Assessment of Wide Complex
Tachycardia: Case 2
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Case 2
Typical LBBB
Wide Complex Tachycardia
Case 2
• Treated with adenosine 6 mg, repeated once, then
NSR
• Loaded with digoxin, 0.5 mg, then 0.25 mg, and
final dose of 0.25 mg
Case 2: normal sinus rhythm
Case 2
NSR Frontal Axis
Case 2
NSR precordial Axis
Wide Complex Tachycardia
Case 3
• 29 yr. old previously healthy woman, noted
dizziness and fatigue at work.
• She’d had similar symptoms, episodically, over the
prior two weeks.
• Medications included Zoloft, oral contraceptives,
and occasional Sudafed. She rarely used cocaine
• Exam showed HR of 280 BPM, BP 120/70, resp
18/min
Case 3
Case 3
Stepwise Assessment of Wide Complex
Tachycardia: Case 3
• Are RS complexes absent in all precordial leads?
Stepwise Assessment of Wide Complex
Tachycardia: Case 3
• Does any RS interval exceed 100 msec in the
precordial leads?
Stepwise Assessment of Wide Complex
Tachycardia: Case 3
• Is A-V dissociation present?
Stepwise Assessment of Wide Complex
Tachycardia: Case 3
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Case 3
Typical LBBB
Wide Complex Tachycardia
Case 3
• Treated with adenosine 6 mg, 12 mg
• Received Versed 1 mg, then direct current cardioversion
100 J, without success
• Received Versed 1 mg, then direct current cardioversion
200 J, without success
• Received Propofol, then direct current cardioversion 350 J,
with success
Case 3: normal sinus rhythm
Case 3
NSR Frontal Axis
Case 3
NSR precordial Axis
Stepwise Assessment of Wide Complex
Tachycardia
• Are RS complexes absent in all precordial leads?
• Does any RS interval exceed 100 msec in the
precordial leads?
• Is A-V dissociation present?
• Do the QRS complexes in V1/V2 fulfill the classic
criteria?
Wide Complex Tachycardia
summary
• WCT can be VT or SVT
• Knowledge of basic appearance of “normal”
RBBB and LBBB can be helpful
• Hemodynamic stability does NOT help make the
diagnosis
• If hemodynamically stable and in doubt, treat as
VT
• If unstable, apply direct current cardioversion
Session 5 ECGs
5A
5B
5C
5D
5E
5F
5G
5H
5I
5J
5K
5L
5M
5N
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Session 6 ECGs
6A
6B
6C
6D
6E
6F
6G
6H1
6H2
6H3
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Session 7 ECGs
7A
7B
7C
7D
7E
7F1
7F2
7F3
7F4
7F5
7G1
7G2
7G3
7H
7I
7J
7K
7L1
7L2
7L3
7M
Course Outline
• Basic ECG analysis and sinus rhythm
• Intervals, Bundle Branch Block, Hypertrophy and
Enlargement
• Supraventricular arrhythmias
• Ventricular arrhythmias
• Bradyarrhythmias
• Heart Blocks
• Ischemia and Infarction
• Miscellaneous Abnormalities
Session 8 ECGs
8A
8B
8C
8D
8E
8F
8G
8H
8I
8J
8K
8L
8M
8N
8O1
8O2
8P1
8P2