Bronze Level Electrocardiography
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Transcript of Bronze Level Electrocardiography
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Bronze Level Electrocardiography
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Aims
1. Brief summary of relevant clinical electrophysiology
2. Indications for taking an electrocardiogram (ECG)
3. How to obtain a diagnostic ECGAll Covered in Part 1
4. Basic ECG interpretation
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Section 4 – basic ECG interpretation
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Premature QRS complexes – wide or narrow QRS morphology
Trace 1
Trace 2
Both of these traces show premature QRS complexes. These are complexes with a shorter R-R interval than the preceding sinus beats
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Trace 1
Trace 1: The first 4 complexes show sinus rhythm. The 5th QRS complex is a premature beat with no associated P wave and a wide bizarre QRS morphology which suggests that it is not being conducted through the ventricles via the normal conduction system. As this beat originates in the ventricles it is termed a ventricular premature beat or VPC. The remainder of the trace shows sinus rhythm.
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Trace 2
Trace 2: Shows premature narrow QRS complex beats (the 2nd, 5th, 8th, 11th and 14th beats). These are supraventricular premature beats or SPC.
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Escape beatsSinus rhythm
Sinus arrest with ventricular escape rhythm
Escape beats are less common than premature beatsEscape beats occur after an interval GREATER than the normal R-R interval (cf premature beats occur after an interval LESS than the normal R-R interval) Escape beats have a wide and bizarre complex morphology as they originate from the ventricles. Escape beats maintain cardiac output during sinus arrest.
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Potentially life threatening ECGs
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Potentially life threatening ECGs – ventricular tachycardia
Sinus rhythm Ventricular tachycardia
Characteristics of VT:• Rapid (>180bpm) • Generally regular• More than 6 consecutive wide, bizarre QRS complexes• Seen in animals with severe cardiac and/or systemic disease (eg gastric dilation torsion,
pancreatitis, splenic disease, IMHA, etc).• Of particular concern in Boxers, Dobermanns and Great Danes
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Potentially life threatening ECGs – coarse ventricular fibrillation
Ventricular fibrillation is characterised by very rapid baseline undulations.
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Potentially life threatening ECGs – fine ventricular fibrillation
Usually a terminal rhythmRapid baseline undulations of lower amplitude to coarse VT.In this cases progresses to complete asystole and death around 11:27.
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Potentially life threatening ECGs - asystole
Flatline as there is no organised atrial or ventricular activity
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Potentially life threatening ECGs – high grade second degree atrioventricular block
P QRS T
PP P P P P P P
Large number of consecutive unconducted P waves (blocked at atrioventricular node or AVN). Finally a P wave is conducted through the AVN resulting in a normal QRS complex.There are then 13 consecutive unconducted P waves before the next P-QRS-T complex.
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Potentially life threatening ECGs – sinus arrest with very slow escape rhythm
During this 10 second period only a single beat is seen therefore the heart rate is very slow during this recording. The beat seen has a bizarre QRS morphology and is not preceded by a P wave suggesting that it is ventricular in origin.
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