Back to Medical SchoolECG interpretation – made easy !

Dr Rob Sapsford

The Yorkshire Heart Centre

Leeds General Infirmary

ECG’s have become more convenient

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LV

RV

LA

RA

Lead error

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Lead error

Normal ECG

4 large squares

300/large squares = rate

Machine reported as “old inferior infarct”

Pathological Q-wave

•>25% r wave

•>1 small square across

Clinical context

Be wary of overly sensitive ECG machine computer reports

Incomplete RBBB

RBBB

LBBB

1.

QT interval

QT interval

Normal up to 12 small squares (dependent rate)

(0.450s)

QT Interval Calculation

TangentBaselin

e

QT

R-R interval

QT Interval = QT / R-R interval

Case studies

LVH (several criteria) simple rule:

Limb lead (I / AVL) – 12 mmHg >

Chest leads (V1 S + V5/6 R) => 35 mmHG

Atrial fibrillation – fast ventricular response

Sinus tachycardia

SOB 60 yr old woman

Left Bundle Branch Block

Intermittent palpitations at rest

Ventricular ectopy

1st degree AV block (heart block)

2nd degree AV block (Mobitz type II)

2:1 AV block

Exercise intolerant 73 yr old man

3rd degree AV block (complete heart block)

Atrial flutter with 2:1 block

AF and complete heart block

78 year old woman; chest pain yesterday

acute coronary syndrome- widespread ischaemia

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Chest pain - acute

Anterior septal acute coronary syndrome

Sharp chest pain worse lying flat

Pericarditis

Acute inferior ST elevation MI

Palpitations

Broad complex tachycardia

RVOT VT

Summary

• Review of ECG interpretation• Rate, Rhythm, (Axis) • P wave, QRS and relationship• Common pitfalls

• Can be difficult– The computer is overly sensitive, but can be helpful– Someone to discuss with is reassuring