Devices: Difference between revisions

203 bytes added ,  5 August 2012
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==Pacemakers==
==Pacemakers==
[[Image: |right]]
[[Image:SchematicImg.jpg|right|thumb|300px|Schematic display of a pacemaker.]]


A pacemaker monitors the electrical impulses in the heart. When needed, it sends small electrical impulses to the heart muscle to maintain a normal heart rate.  
A pacemaker monitors the electrical impulses in the heart. When needed, it sends small electrical impulses to the heart muscle to maintain a normal heart rate.  
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===Explanations of table:===
===Explanations of table:===
====III====
====III:====
=====Triggered:=====  
=====Triggered:=====
A sensed event triggers a pacemaker output pulse  
A sensed event triggers a pacemaker output pulse  
=====Inhibited:=====
=====Inhibited:=====
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==Complications==
==Complications==
===Undersensing:===  
===Undersensing:===  
[[Image:Ventricular undersensing.svg|right|thumb|300px]]
[[Image:Ventricular undersensing.svg|right|thumb|300px|Ventricular undersensing. Failure of appropriate ventriculation inhibition]]


An intrinsic depolarization that is present, is not sensed by the pacemaker. This can be due to:
An intrinsic depolarization that is present, is not sensed by the pacemaker. This can be due to:
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===Oversensing:===  
===Oversensing:===  
[[Image:Ventricular oversensing.svg|right|thumb|300px]]
[[Image:Ventricular oversensing.svg|right|thumb|300px|Ventricular oversensing. Failure of appropriate ventricular firing]]


The pacemakers senses signals on the marker channel that do not correspond to the ECG pattern. This can be physiologic (e.g. ventricular pulse or myopotentials) or non-physiologic (e.g. lead fracture or if the lead is loose from the pacemaker pulse generator or outside interference such as TENS therapy or surgical diathermy).
The pacemakers senses signals on the marker channel that do not correspond to the ECG pattern. This can be physiologic (e.g. ventricular pulse or myopotentials) or non-physiologic (e.g. lead fracture or if the lead is loose from the pacemaker pulse generator or outside interference such as TENS therapy or surgical diathermy).
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