ECG Interpretation by USAMA ELSAYED
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Transcript of ECG Interpretation by USAMA ELSAYED
Basics of ECG interpretation
BYUSAMA ELSAYED
Lecturer of anesthesia and intensive care
Objectives Why ECG?
How to monitor ECG
Physiology of pulse conduction
Interpretation
WHY?Chest pain
Heart failure
Collapse / syncope
Shock / hypotension
Palpitations
Cardiac arrest
preoperative
GOLDEN RULE
Look at the patient
not just the paper
How ? 3-lead monitoring
12-lead monitoring
‘Quick-look’ paddles
Hands-free adhesive pads
12 lead monitoring
6 chest electrodes Called V1-6
4 limb electrodes
Right arm RideLeft arm YourLeft leg Green Right leg B ike
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje f ibers
Normal Impulse Conduction
Impulse Conduction & the ECG
ECG Paper
ECG Leads
ECG waves components P wave = atrial depolarisation
QRS = ventricular depolarisation
T = repolarisation of the ventricles
ECG interpretation
History
QRS Rhythm QRS Rate QRS Width QRS Axis
P Wave P & QRS Relation Ischemic changes
History Again: treat the patient not the paper Check o Name and age o Time and date o Indication (chest pain or routine pre op) o Any previous or subsequent ECGs (Is it
part of a serial ECG sequence?)
IIII
QRS Rhythm
QRS Rhythm Sinus Rhythm Cardiac impulse originates from the sinusnode. Every QRS must be preceded by P
wave ????
Sinus not normal sinus ??
2- QRS
RATE
* At standard paper speed of 25 mm sec-1, 5 large squares = 1 second* At standard paper speed of 25 mm sec-1, 5 large squares = 1 second
QRS Width The width of the QRS complex should
be less than 0.12 seconds (3 small squares)
suggests a ventricular conduction problem usually right or left bundle branch block (RBBB or LBBB)
QRS
WIDTH
LBBB
RBBB
02/20/15Dr Gamal Abbas
NOV 2007 24
02/20/15Dr Gamal Abbas
NOV 2007 25
QRS Height
RVH: V1 R/S ratio >1 or V6 S/R ratio >1.
LVH: S in V1 or V2 + R in V5 or V6 ≥ 35 mm
The QRS Axis Represents the overall direction of the heart’s activity
Axis of –30 to +90 degrees is normal
The QRS Axis Left axis deviation(LAD)
o Inferior MI
o LVH
o Left anterior hemiblock
The QRS Axis Right axis deviation(RAD)o RVH
o Anterolateral MI
o Left posterior hemiblock
P Wave
P WaveAtrial activity
Positive in II
Negative in aVR
Height A tall P wave (over 2.5mm) can be called P
pulmonale As in right atrial enlargemento Pul. Htno TSo PS
P Wave Length> 2.5 small squares and a bifid shape is
called P mitrale Left atrial hypertrophy
o Mitral valve disease
o LVH
P & QRS Relationship 2 Questions
o Is every P followed by QRS?
o PR Interval
The PR interval measured between the start of the P
wave to the start of the QRS complex.
time between depolarisation of the atria and ventricular depolarisation.
3- 5 small squares(0.12 - 0.2 sec)
Relation between atrial and ventricular activity
Heart Block: First Degree
first degree ht block
Möbitz Type I (Wenckebach) Block
Möbitz Type II Block
Relation between atrial and ventricular activity
Heart Block: Third Degree
Relation between atrial and ventricular activity
The ST segment , T and Q wave (Ischrmic changes) ST segment Sit on the isoelectric
line Abnormal if there is planar (i.e.
flat) elevation or depression of the ST segment
The ST segment , T and Q wave (Ischrmic changes)
Baseline
The ST segment , T and Q wave (Ischrmic changes)
Width of Q wave is 0.04 secs
Peaked T wave as in hyper kalemid
I and AVL
II, III and AVF
V3 & v4
V1 & v2
V5 & v6Where the positive electrode is positioned, determines what part of the heart is seen!
A Normal 12 Lead ECG
Putting it ALL together
Anterolateral myocardial infarction
Inferior myocardial infarctionInferior myocardial infarction
Posterior myocardial infarctionPosterior myocardial infarction
Practice QRS rhythm QRS rate QRS Width P wave P & QRS relationship Ischemic changes
Let’s Practice
PracticeSupraventricular Tachycardia
Atrial Fibrillation
Atrial Flutter ( 2/1 )
Sinus Bradycardia
Practice First degree heart block
Second degree heart block (Mobits type I)
Third degree heart block
Second degree heart block (Mobits type II)
Practice
Anterior MI with lateral involvementST elevations V2, V3, V4 ST elevations II, AVL, V5
Practice
Anteroseptal MIST elevations V1, V2, V3, V4
Practice
Inferior MIST elevation II,III AVF
Practice
Inferior lateral MIST elevations II, III, AVFST elevations V5
Practice
•Acute inferior MI•Lateral ischemia
Normal
RBB w/inferior MI
Atrial fibrillation
Normal
Ventricular tachycardia
Normal
Right bundle branch block.
Lateral MI
Reciprocal changes
Common Dangerous Rhythms
Asystol
P wave Asystol
Course Ventricular Fibrillations
Fine Ventricular Fibrillations
Criteria of ventricular fibrillations* Bizarre irregular waveform * No recognisable QRS complexes
* Random frequency and amplitude
Common Dangerous Rhythms (Ventricular)
Ventricular Tachycardia
Torsade De Pointes
Any questions
Remember
Practice makes perfect .