ECG PRACTICAL ECG PRACTICAL APPROACHAPPROACHDr. Hossam HassanDr. Hossam Hassan

Consultant Emergency MedicineConsultant Emergency Medicine

Objectives Objectives

• To emphasize simplicities

• Practical approach

• Interpretation & clinical scenario are inseparable

• Systematic approach

Conduction SystemConduction System

Nomenclature Nomenclature

Magic numbers of Dr. HossamMagic numbers of Dr. Hossam

Systematic approachSystematic approach

• Rate• Rhythm• axis

• P-wave• PR interval• QRS complex• ST segment• T-wave

Rate Rate

• The interval between 2 successive R-wave

• How many big squares?

• Divide 300 / # big squares

• Normal 60 – 100/min

Rhythm Rhythm

Sinus Rhythm

Every P=wave is followed by QRS complex

P-wave is upright in lead II

NSRNSR

Types of Sinus RhythmTypes of Sinus Rhythm

• NSR

• Sinus Tachycardia

• Sinus Bradycardia

• Sinus arrhythmia

Sinus tachycardiaSinus tachycardia

Axis Axis

• Normal axis

• Right axis deviation

• Left axis deviation

RADRAD

LADLAD

P-waveP-wave

• Atrial depolarization

• Atrial contraction is a result

• Normally a dome-like structure

Abnormalities of P-waveAbnormalities 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-pulmonaleP-pulmonale

PR intervalPR interval

• Definition

From the start of P to beginning of QRS

• Represent the delay in transmission in AV node

• Normally 0.12 – 0.20 msec

Abnormalities of PR intervalAbnormalities of PR interval

• Prolonged >

1st degree HB

• Short <

Pre-excitation syndromes– WPW Syndrome– LGL Syndrome

Junctional rhythm

QRS ComplexQRS Complex

• Amplitute

• Duration

• Shape

• Q-wave

• R-wave

QRS AMPLITUTEQRS AMPLITUTE

• LVH By voltage criteria – S-wave in V 1 or V 2 + R-wave in V5 or V6

LVH & STRAIN PATTERNLVH & STRAIN PATTERN

Causes of LVHCauses of LVH

• HTN

• Aortic stenosis

• HOCM

• Aortic regurgitation

• Mitral regurgitation

QRS DURATIONQRS DURATION

• Ventricular depolarization

• Ventricular contraction is a result

• Normally < 0.12 msec

< small squares

Causes of wide QRSCauses of wide QRS

• Ventricular tachycardia

• BBB– Left BBB– Right BBB

L BBBL BBB

R BBBR BBB

Shape Shape

• Upstroke & downstroke of R-wave

• Delta wave

Q-waveQ-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+ve R-wave in V1

Causes +ve R-wave in V ICauses +ve R-wave in V I

• RVH

• R BBB

• Posterior MI

• Type A WPW

ST-SegmentST-Segment

• From the end of S-wave to the beginning of T-wave

• Normally iso-electric

• Abnormalities– Elevated– depressed

Elevated ST segmentElevated ST segment

• Acute MI

• Pericarditis

• Early repolarization pattern in the young

Infarct localizationInfarct localization

• Inferior– Lead II , III , aVF

• Septal – 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 MIAcute inf MI

Anteroseptal MIAnteroseptal MI

Anterior MIAnterior MI

Lateral MILateral MI

Depressed ST SegmentDepressed ST Segment

• Unstable angina

• Left ventricular strain pattern

LVH & strain patternLVH & strain pattern

T-waveT-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 CHANGESDYNAMIC T-WAVE CHANGES

Hay….. Hay….. wake up we wake up we

are doneare done