ECG PRACTICAL APPROACH Dr. Hossam Hassan Consultant Emergency Medicine

Objectives To emphasize simplicities Practical approach Interpretation & clinical scenario are inseparable Systematic approach

Conduction System

Nomenclature

Magic numbers of Dr. Hossam 3 5

Systematic approach 3 5 Rate Rhythm axis P-wave PR interval QRS complex ST segment T-wave

Rate 5 3 The interval between 2 successive R-wave How many big squares? Divide 300 / # big squares Normal 60 – 100/min 5 3

Rhythm Sinus Rhythm Every P=wave is followed by QRS complex P-wave is upright in lead II

NSR

Types of Sinus Rhythm NSR Sinus Tachycardia Sinus Bradycardia Sinus arrhythmia

Sinus tachycardia

Axis Normal axis Right axis deviation Left axis deviation

RAD

LAD

P-wave Atrial depolarization Atrial contraction is a result Normally a dome-like structure

Abnormalities of P-wave Peaked p-pulmonle Pulmonary HTN PE Pulmonary valve stenosis M-shaped M-mitrale Mitral valve stenosis Left atrial hypertrophy Inverted 2nd atrial / junctional ectopy

P-pulmonale

PR interval 3 5 Definition From the start of P to beginning of QRS Represent the delay in transmission in AV node Normally 0.12 – 0.20 msec 3 5

Abnormalities of PR interval 5 Prolonged > 1st degree HB Short < Pre-excitation syndromes WPW Syndrome LGL Syndrome Junctional rhythm 3

QRS Complex Amplitute Duration Shape Q-wave R-wave 5

QRS AMPLITUTE 35 LVH By voltage criteria S-wave in V 1 or V 2 + R-wave in V5 or V6 35

LVH & STRAIN PATTERN

Causes of LVH HTN Aortic stenosis HOCM Aortic regurgitation Mitral regurgitation

QRS DURATION 3 Ventricular depolarization Ventricular contraction is a result Normally < 0.12 msec < small squares 3

Causes of wide QRS Ventricular tachycardia BBB Left BBB Right BBB

L BBB

R BBB

Shape Upstroke & downstroke of R-wave Delta wave

Q-wave 1st negative deflection after the P-wave Normally 1mm wide & 2 mm deep Lead III , V5 & V6 Pathological Q-wave Wider & deeper >1/4 of the ensuing R-wave Old MI

+ve R-wave in V1

Causes +ve R-wave in V I RVH R BBB Posterior MI Type A WPW

ST-Segment From the end of S-wave to the beginning of T-wave Normally iso-electric Abnormalities Elevated depressed

Elevated ST segment Acute MI Pericarditis Early repolarization pattern in the young

Infarct localization Inferior Septal Anterior Lead II , III , aVF V I , V II Anterior V3 , V4

Lateral Lead I , AVL,V5 , V6 Posterior MI - Prominent R wave in V1,V2 with depressed ST segment

Acute inf MI

Anteroseptal MI

Anterior MI

Lateral MI

Depressed ST Segment Unstable angina Left ventricular strain pattern

LVH & strain pattern

T-wave Ventricular repolarization Dome like structure Abnormalities Peaked / tented t-wave Hyperkalaemia Subendocadial ischemia Inverted LV Strain pattern Dynamic t-wave changes of ischemia

DYNAMIC T-WAVE CHANGES

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