ECG interpretation Dr. Shamim Nassrally BSc (Hons) MB ChB MRCP(UK) Clinical Teaching Fellow

ECG interpretation

Dr. Shamim NassrallyBSc (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