Professor Hamid IkramClinical Professor of Medicine

University of Otago

Consultant Cardiologist

Christchurch

16:30 - 17:30 WS #131: Interpreting ECGs

“ECGs,EKGs,Cardiograms, Cardiographs etc”

Hamid Ikram

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MAKING ECG’S EASY

From the apogee of cardiological testing to the nadir

WHY DO IT?

What Do You Get From it • Precise Time/Voltage Data- think rhythm disorders.

• Some empirical anatomico-pathological information

unreliable ++

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RELATIONSHIP

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THE CONDUCTING

SYSTEM some are silent as the ‘h’

• SA Node

• Inter-nodal pathway

• AV Node

• Bundle of HIS

• Bundle Branches

• Purkinje Fibres

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CARDIAC CYCLES

Intervals

What is the normal PR interval?–0.12 to 0.20 s (3 - 5 small squares).

•Short PR – Look for Wolff-Parkinson-White.

•Long PR – 1st Degree AV block

What is the normal QRS? –< 0.12 s duration (3 small squares).

•Long QRS - look for bundle branch block, ventricular pre-excitation, ventricular pacing or ventricular tachycardia

What is the normal QTc (QT/square root of RR)? –< 0.42 s.

•Long QTc can lead to torsades to pointes.

Bazetts’ Formula

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Automated reports are often inaccurate,

dangerous and in some circumstances can be

lethal.

“Omni scrutio perculosa est”- Erasmus

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LIMB LEADS

• Bipolar leads

I II III

• Augment leads

Avr Avl Avf

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CHEST LEADS

• 6 UNIPOLAR LEADS

• V1

• V2

• V3

• V4

• V5

• V6

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IS the ECG HOOKED UP

CORRECTLY?

LIMB LEADS

Normal 12-lead

• AVR – always negative

• Lead I – always positive

• Lead II, III – positive or biphasic

CHEST LEADS

COLUMN III

• R wave progression

• Small to Tall

COLUMN IV

• R wave progression

• Tall to Small

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ARTIFACT ON THE ECG

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FIND THE ARTEFACT

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SOMATIC TREMOR

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ELECTRICAL INTERFERANCE

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LOOKING AT THE RHYTHM

• Evaluate the rhythm

strip at the bottom of

the 12-lead for the

following

• Is the rhythm regular or

irregular?

• Is there a P wave

before every QRS

complex

• Are they any abnormal

beats.

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ECTOPIC BEATS

LET’S DO SOME PRACTICE

CASES

Case #1

70 year old male with history of diabetes

mellitus and hypertension occasionally feels

lightheaded. He recently fainted while

standing.

Case #1 ECG

Case #2

58 year old female with no significant past

medical history presents with fatigue,

lightheadedness and shortness of breath.

Case #2 ECG

Case #3

78 year old female with history of HTN, DM,

HL, CAD admitted for syncope complains of

palpitations and lightheadedness.

Case #3 ECG

Case #4

67 year old male with history of diabetes,

hypertension, COPD presents with chest pain.

Case #4 ECG

Case #5

60 year-old man with history of HTN, HL, CAD

presents with nausea, shortness of breath

and chest pain.

Case #5 ECG