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ECG interpretation. Dr. Shamim Nassrally BSc (Hons) MB ChB MRCP(UK) Clinical Teaching Fellow. Objectives. By the end of this session you should be able to: Interpret ECGs using a systematic approach Recognise important ECG abnormalities: acute coronary syndrome
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ECG interpretation Dr. Shamim Nassrally BSc (Hons) MB ChB MRCP(UK) Clinical Teaching Fellow
Objectives By the end of this session you should be able to: • Interpret ECGs using a systematic approach • Recognise important ECG abnormalities: • acute coronary syndrome • acute myocardial infarction • common arrhythmias.
Framework • Basic information/Demographics • Rate • Rhythm • Axis • P wave and PR interval • QRS complex • ST segment
Basic information • Identifying information: name/unit number • Date/time • Voltage (10mm/mV) • Speed (25mm/s)
Rate • 300/number large squares • Normal: 60-100bpm • <60 = bradycardia • >100 = tachycardia
Rhythm • Are there P-waves? • Is each P followed by a QRS? • Is each QRS preceded by a P wave? • AF/atrial flutter • Supraventricular tachycardias • Heart block: • 1st degree • 2nd degree (Mobitz type 1 and type 2) • 3rd degree (complete heart block)
P wave and PR interval • Normal P wave <2.5mm high, <0.11s • Normal PR interval 0.12-0.2s (3-5 small squares)
Axis • I and II positive = normal axis • I positive + III negative = left axis deviation • I negative + III positive = right axis deviation
QRS complex • Normal QRS <0.12s (3 small squares) • LVH criteria • Wide QRS • Left bundle branch block • Right bundle branch block
ST segment • ST elevation: MI, left bundle branch block • ST depression: ischaemia, posterior MI, digoxin • T-wave: • Tall – hyperkalaemia, left bundle branch block • Flat – ischaemia, hypokalaemia
Quiz • Rate • Rhythm • P wave, PR interval • Axis • QRS complex • ST segment • T waves