Back to Medical School ECG interpretation – made easy ! Dr Rob Sapsford The Yorkshire Heart Centre Leeds General Infirmary

ECG’s have become more convenient

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7/126 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 Normal up to 12 small squares (dependent rate) (0.450s)

QT Interval Calculation Tangent BaselineQTR-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

1 st 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

32/126 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