baby steps to ecg dr saqib mahmud mrcp(uk), mrcps(glasg), mrcgp

Baby Steps to ECG

Dr Saqib MahmudMRCP(UK), MRCPS(Glasg), MRCGP

Electrical Conducting system

ECG LEADS

leads representing regions

Anatomic region of heart & associated coronary artery

• Inferior MI----------------RCA

• Antero-septal MI---------LAD

• Antero-lateral MI---------Circumflex

• Posterior MI--------------RCA

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• Inferior leads-------------II, III, aVF

• Antero-septal leads------V1,V2,V3&V4

• Antero-lateral leads------I,aVL,V2-V6

Normal ECG

PR interval0.12s-0.2s(not>1 large sq)

QRS duration0.12s(not>3 small squares)

PQRST

ST segmentisoelectric

T upright

ECG reporting-systematic approach

1. Rate

2. Rhythm & P waves

3. Conduction intervals

4. Axis

5. QRS complexes-narrow, wide, bizarre

6. ST segments-elevation or depression

7. T waves-inverted, upright, peaked

How to calculate heart rate

Relationship b/w R-R interval (large squares)& heart rate

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R-R interval (large squares) heart rate• 1 300• 2 150• 3 100• 4 75• 5 60• 6 50

QRS nomenclature

Axis

Cardiac axis• Normal axis-’’ double thumbs

up’’(I&III+)

• RAD--- I –ve, III +ve• LAD--- I +ve, III –ve• ---------------------------------------------• RAD-(causes): normal in children, R

vent hypertrophy, PE, ASD/ VSD, antero-lateral MI

• LAD-inferior MI, WpW, emphysema, conduction defects

Bundle branch block

• RBBB

1. Tall R wave V1

2. QRS>0.12sec

3. RsR-V1

• LBBB

1. QS-V1,V2

2. QRS>0.12

LBBB

RBBB+LAD

Atrial flutter & fibrillation

• Atrial flutter1. Saw tooth appearance2. Rapid & regular rhythm• Atrial fibrillation1. No P waves or bizarre P waves2. Always irregular rhythm3. Can be slow or rate controlled

ACS classification

Heart block• 1st degree HB-prolonged PR>0.2secCauses-increased vagal tone, IHD, Rh fever, dig

toxicity, electrolyte imbalance,myocarditis

• 2nd degree HB-1. Mobitz type 1 or wenckebeck-

progressively increased PR,non conducted beat,short PR (causes-inf MI, athelete, drugs-Ca & beta blockers,digoxin)

2. Mobitz type 2-(2:1) fixed PR, one P wave not folowed by QRS-(causes-degenerative disease of conducting system, anteroseptal MI-may herald CHB)

CHB or 3rd degree HB• Atrial contraction normal-no beats

conducted to ventricles• Ventricles excited by slow escape

rhythm• ECG-no relationship b/w P waves and

Q waves• Bizarre or wide QRS complexes• Causes-degenerative fibrosis of

bundle of his, MI, drugs eg betablockers, digoxin

wpw

hyperkalaemia

P-pulmonale

SI,QIII,TIII-RV strain

Thank you Presentation

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Peripheral vascular diseaseNext time if you are

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