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
on
Peripheral vascular diseaseNext time if you are
interested
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