Aims The ECG complex Step by step interpretation Rhythm disturbances Axis QRS abnormalities Acute...
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Transcript of Aims The ECG complex Step by step interpretation Rhythm disturbances Axis QRS abnormalities Acute...
Aims
• The ECG complex• Step by step
interpretation• Rhythm
disturbances• Axis• QRS abnormalities• Acute and chronic
ischaemia• Miscellaneous ECG
abnormalities
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The ECG Complex
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The ECG Complex• (diagram of ECG complex)
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Nomenclature
• P Wave• QRS complex• T wave• U wave• PR interval• QT interval• RR interval (ventricular) heart rate
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Intra-cardiac electrical conduction
• (diagram of intra cardiac electrical conduction)
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Standard 12 Lead ECG
(Example of normal ECG)
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Standard Times
Interval (ms)
PR 120 – 200
QTc (Corrected for heart rate)
Men: 390-450Women: 390-460
QRS <110
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Step by step interpretation
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Step by step interpretation
• Rate• Rhythm• Axis• QRS complex• ST segments
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RATE
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Rate• Normal heart rate 60-100bpm• Bradycardia < 60bpm• Tachycardia > 100bpm
• Divide tachycardia into ‘broad’ and ‘narrow complex’
• Broad = QRS > 110ms• Narrow = QRS <110ms
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Rhythm
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Regular or irregular?
• Measure R-R interval between different complexes
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Sinus rhythm
Rhythm14
(example showing sinus rhythm)
Where else may heart rhythm originate from?
• Atria – Atrial fibrillation– Atrial flutter– Atrial tachycardia
• In/around AV node– nodal ‘junctional’ rhythm– AVNRT/AVRT
• Ventricle– VT/VF
* Will be demonstrated
Rhythm15
Atrial Fibrillation
• Erratic atrial depolarisation• No discernible p waves• Rate varies• Irregular
(example showing atrial fibrillation)
Rhythm16
Atrial Flutter
• Cyclical electrical activity around right atrium
• Atrial complexes occur at approx 300/min• ‘Sawtooth’ appearance on ECG• Almost always associated with degree of
AV block(example showing atrial flutter)
Rhythm17
Junctional (Nodal) Rhythm
• Uncommon• Rhythm arises from around AV node• Narrow complex
(example showing junctional rhythm)
Rhythm18
Accelerated ‘Idioventricular’ rhythm
• Unusual• Heart rhythm controlled by ventricular
focus• Usually 60-120bpm
(example showing idioventricular rhythm)
Rhythm19
Ventricular tachycardia
• Wide QRS• Heart rate >120bpm• Life-threatening
• (example of VT)
Rhythm20
Ventricular Fibrillation
Rhythm21
• (example showing ventricular fibrillation)
Bradycardia
• Types– Sinus bradycardia (very rarely less than
40bpm)– Sick sinus syndrome– Slow AF/atrial flutter (usually drug related)– Atrioventricular (AV) block
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Sinus Bradycardia
• (example showing sinus bradycardia)
Rhythm23
Sick Sinus Syndrome
• Sinus arrest
• (example of sinus arrest)
Rhythm24
AV block
• 1st degree (prolonged PR interval)
• (example of 1st degree AV block)
Rhythm25
2nd Degree AV block
• Mobitz type 1 (Wenckebach)
• (Example showing 2nd degree mobitz type 1 block)
Rhythm26
2nd Degree AV block
• Mobitz type 2• (Example showing Mobitz type 2 2:1 AV
block)
Rhythm27
AV Block
• 3rd degree (complete heart block)
• (Example of complete heart block)
Rhythm28
Axis
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Axis
• ‘Mean frontal plane axis’• Determined by vector of dominant
(maximal QRS deflection)• Normal: -30 to 90 degrees• Left deviation -90 to -30 degrees• Right deviation 90 to 180 degrees
Axis30
Axis
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• (diagram explaining axis alongside normal ECG)
Axis
• Check leads I and II• If the complexes are both positive: normal• If the complexes ‘Leave’ each other: Left• If the complexes ’Reach’ each other: Right
Axis32
QRS abnormalities
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QRS complexes
• Wide? (> 110ms) – Suggests either rhythm arising below AV node or– Conduction delay down bundle of his
QRS abnormalities34
Left bundle branch block
QRS abnormalities35
• (diagrams of LBBB and diagram of leads V1 and V6)
Right bundle branch block
QRS abnormalities36
• (diagrams of LBBB and diagram of leads V1 and V6)
Left/right bundle
WiliaM
MarroW
QRS abnormalities37
• (diagrams of leads V1 and V6)
LVH/RVH
• LVH Criteria:– S wave in V1 + tallest R wave in V5 >35mm– Many other criteria – Caution when LBBB present
• RVH criteria:– Dominant R wave (>6mm) V1– Deep S wave >10mm V5 or >3mm V6
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Ischaemia
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Ischaemic territories
Ischaemia40
(Illustrated example showing ischaemic territories)
Chronic ischaemia/ Q waves
• Normal in aVR/V1• > ½ small square wide and 1 small square
tall
(example of q wave)
Ischaemia41
Acute ischaemia
• T wave inversion
(example of t wave inversion)
Ischaemia42
ST depression/elevation
• Describe how far J point is depressed/elevated from isoelectric line
• (diagram of j point)
Ischaemia43
Acute ischaemia
• ST depression(example of ST depression)
Ischaemia44
Acute ST elevation
Ischaemia45
• (example of acute ST elevation)
Miscellaneous Abnormalities
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Digoxin effect
Miscellaneous abnormalities47
• (example of digoxin effect)
QT prolongation
• May be acquired or inherited• (ECG of QT prolongation)
Miscellaneous abnormalities48
Hypokalaemia
Miscellaneous abnormalities49
• (example of hypokalaemia)
Hyperkalaemia
Miscellaneous abnormalities50
• (example of hyperkalaemia)
End of session
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