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| | [[Sino-Atrial Block]] | | [[Sino-Atrial Block]] |
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| | + | [[Atrio-Ventricular Block]] |
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| − | ===2. AV Block===
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| − | *The delay or failure of the atrioventricular node to conduct impulses.
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| − | ====1st Degree (Partial AV Block)====
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| − | *Delayed conduction through the AV node
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| − | '''Causes'''
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| − | Electrolyte imbalance, drug reactions, degenerative changes in the AV node
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| − | '''ECG Appearance:''' Longer P-R interval
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| − | '''Treatment''' Treat the underlying cause
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| − | ====2nd Degree (Partial AV Block)====
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| − |
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| − | *Intermittent failure of conduction through the AV node
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| − |
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| − | '''Mobitz Type I.'''= prolonged P-R interval
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| − | '''Mobitz Type II.'''= no prolongation of the P-R interval
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| − | '''Type A:''' normal QRS length; block is above the bundle of His division (Most commonly seen with Mobitz Type I.)
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| − | '''Type B:''' longer QRS length; block is below the bundle of His division (Most commonly seen with Mobitz Type II.)
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| − | '''Causes''' Electrolyte imbalance, drug reactions, degenerative changes in the AV node
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| − | '''ECG Appearance:''' Some P waves are not followed by QRS complexes
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| − | '''Treatment'''
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| − | Mobitz Type I.: Treat underlying cause if necessary
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| − | Mobitz Type II. Treat with atropine etc. or surgical implantation of a pacemaker
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| − | ====3rd Degree (Total AV Block)====
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| − | *Total failure of AV conduction causing uncoordinated and independent atrial and ventricular depolarisations
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| − | '''Causes''' Electrolyte disturbances, drug toxicities (e.g. digitalis), acquired nodal diseases, cardiomyopathies, hypothyroidism, endocarditis, lymes disease etc.
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| − |
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| − | '''ECG Appearance:''' Independent regular and fast P waves; independent regular and slow QRS waves
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| − | '''Treatment''' Treat underlying disease, atropine etc., implantation of a cardiac pacemaker
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| | ===Atrial Standstill=== | | ===Atrial Standstill=== |