ecg interpretation
DESCRIPTION
ECG interpretationTRANSCRIPT
ECG: Systematic Analysis
Dr Nola McPherson CME SCGH 2014
ECG Interpretation Overview
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
6. QRS complex
7. ST segment
8. T wave
9. U wave
10. QT interval
ECG Interpretation Overview
11.Additional waves (D O E)
12.Chamber hypertrophy
13.Other
- T oxicology
- I schaemia
- E lectrolytes
- sudden death ECG
Q B R A D W H
- dextrocardia
- lead reversals
- artefacts
- pacing spikes
Putting it all together…Diagnosis
Differential diagnoses
Life threats
ECG Interpretation Template
1. ECG type & recording
ECG TYPE & RECORDING 12 lead vs rhythm strip
Paper rate (N= 25mm/s)
Calibration (5mm wide, 10mm high = 1mV)
Unusual leads
- right
- posterior
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
Rate, Rhythm, AxisRATE
Normal 60-100/min (tachy/bradycardia)
Method: 300/RR(large squares)
OR 1500/RR(small squares)
OR number of QRS x 6 (if 25mm/s)
RHYTHM
Pattern: regular or irregular (reg irreg or irreg irreg)
7 STEP APPROACH
Rate, Rhythm, AxisAXIS
Normal (-30 to +90)
RAD
LAD
NW axis
NORMAL SINUS RHYTHM 12 Lead ECG
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
P Wave?present or absent
Amplitude & duration (LAE/RAE/BAE)
<2.5mm amp limb leads, <1.5mm amp chest leads
<3mm duration
Contour monophasic lead II, biphasic lead V1
inverted aVR, upright I, II, V2-6
Left Atrial Enlargement
Left Atrial Enlargement
Right Atrial Enlargement
Right Atrial Enlargement
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
PR Interval Duration (N= 120-200ms)
Short (<120ms)
1. Preexcitation Syndrome
eg WPW, Lown - Ganong- Levine (LGL)
2. AV (nodal) junctional Rhythm
Long (>200ms)
1. 1 HB (alone or with other blocks)
Varying (blocks)
Short PR Interval - WPW
Short PR interval (<120ms)
Prolonged QRS (>110ms) + early slurred upstroke (delta wave)
Dominant R in V1-3
ST seg & T wave discordant changes
Short PR Interval - LGL
Short PR – AV (nodal) Junctional Rhythm
Long PR Interval
PR Segment Elevation or Depression
1. pericarditis
2. atrial ischaemia
- Liu’s Criteria
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
Q waves NORMAL
<1mm wide, <2mm deep
PATHOLOGICAL
Criteria:
- >40ms (>1mm wide)
- > 2mm deep
- >25% depth of QRS complex
- seen in lead V1- V3
DDX:
1. Myocardial infarction
2. Cardiomyopathies
Hypertrophic
Infiltrative disease
Pathological Q Waves
R wavesNORMAL
Transition point V3-V4
ABNORMAL
Dominant R wave in aVR
Dominant R wave in V1
Poor R wave progression (Ht ≤ 3 mm in V3)
Dominant R Wave in aVRCAUSES
1. Poisoning with Na channel blocking medications
(Criteria: R wave height > 3 mm, R/S ratio > 0.7)
2. Dextrocardia
3. Incorrect lead placement (L & R arms reversed)
Dominant R Wave in V1CAUSES
1. RVH (PE, L to R shunt)
2. RBBB
3. POSTERIOR MI (+ STE in leads V7,8,9)
4. WPW TYPE A
5. Hypertrophic Cardiomyopathy
6. Dextrocardia
7. Normal in children and young adults
Poor R Wave ProgressionCAUSES
1. Prior anteroseptal infarction
2. LVH
3. Dilated cardiomyopathy
4. Transpositioin of leads V1 & V3
5. May be normal
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
6. QRS complex
QRS Complex Duration
N = 70-100ms
narrow (Supraventricular)
wide (ventricular or SVT with aberrant
conduction)
Amplitude
High voltage eg LVH
Low voltage
Alternans eg pericardial effusion
Morphology
Notched
RBBB
LBBB
Spot Diagnoses
Brugada Syndrome
WPW Syndrome (delta waves)
Tricyclic poisoning (wide QRS + dom R in aVR
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
6. QRS complex
7. ST segment
ST Segment Displacement
Elevation
Depression
ST Depression Morphology
Horizontal
Up sloping
Down sloping
ST Segment Elevation
ST Segment Depression
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
6. QRS complex
7. ST segment
8. T wave
T WaveNormal
= < 5mm height in limb leads = < 15mm height in precordial leads = < 2/3 R
= <15 mm ht in precordial leads = < 2/3 R
T Wave Amplitude & Morphology
Peaked eg hyperkalaemia
Flat eg myocardial ischaemia, hypoK
Hyperacute eg early STEM, Prinzmetal angina
Inverted eg ischaemia & infarction, increased ICP
Biphasic eg Myocardial ischaemia, hypoK, Wellens
T Wave Morphology
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
6. QRS complex
7. ST segment
8. T wave
9. U wave
U Wave Normal
= 0.5 mm (max 2mm)
= 10% TW (max 25% TW)
Prominent
Inverted
U Wave Prominent
> 1-2mm or > 25% ht TW
CAUSES
Bradycardia
HypoK
HypoCa, HypoMg
Hypothermia
Increased ICP
LVH
Hypertrophic cardiomypy
Digoxin
Inverted
abnormal if in leads with upright T waves
CAUSES
Heart disease
**HIGHLY SPECIFIC FOR HEART DISEASE**
**Predicts >75% stenosis of LAD/LMCA and suggests LV dysfn**
ECG Interpretation Template
1. ECG type &recording
2. Rate, Rhythm, Axis
3. P wave
4. PR interval + segment
5. Q Waves, R waves
6. QRS complex
7. ST segment
8. T wave
9. U wave
10. QT interval
QT Interval Normal QTc
= 390-440ms M/460 ms F
< ½ preceding RR
inversely prop to HR
Measure in lead II or V5-6
Large U waves (>1 mm) fused to T included in measurement
Small, separate U waves excluded in measurement
Long (>440/460 ms)
Short (<350ms)
QT Interval
ECG Interpretation Template
11. Additional waves (D O E)
Additional Waves (D O E) Delta Wave
WPW
= slurred upstroke to QRS
Additional Features:
Short PR interval (<120ms)
Broad QRS (>100ms)
Additional Waves (D O E) Osborn Wave (J waves)
= positive deflection at J point
Most prominent in precordial leads
Causes
Hypothermia
Hyper Ca
Medications
Raised ICP
Normal varient
Additional Waves (D O E) Epsilon Wave
Arrythmogenic RV dysplasia (in 30% patients)
= pos deflection buried in end of QRS
Additional Features
TWI V1-3
Prolonged S Wave upstroke V1-3
ECG Interpretation Template
11.Additional waves (D O E)
12.Chamber hypertrophy
13. Other
- T oxicology
- I schaemia
- E lectrolytes
- sudden death ECG
- dextrocardia
- lead reversals
- artefacts
- pacing spikes
Lethal Causes SyncopeQ BRAD W H
1. QT syndrome (Long/short)
2. Brugada Syndrome
3. RV infarction
4. Arrythmogenic RV Dysplasia
5. Dilated Cardiomyopathy
6. WPW
7. Hypertrophic Cardiomyopathy
Questions & Comments
ReferencesWhat-When-How In Depth Tutorials and
Information: http://what-when-how.com/paramedic-care/diagnostic-ecgthe-12-lead-clinical-essentials-paramedic-care-part-5/
ECG Basics-Parts of the ECG: http://www.emergsource.com/?page_id=90
Academic Life in Emergency Medicine: http://www.aliem.com/posterior-myocardial-infarction-how-accurate-is-the-flipped-ecg-trick/
References ECG PEDIA.ORG: http://en.ecgpedia.org/wiki/
QRS_axis
Life in the Fast Lane ECG Library