Term
| where is the SA node? what part of the EKG is it responsible for? |
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Definition
| the SA node sits on the posterior wall of the RA and is constantly releasing an electrical signal - the P wave |
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Term
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Definition
| the first downward deflection (must be deep and wide to be significant, which could indicate an MI) |
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Term
| what is the PR interval? what does it do? |
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Definition
| the time after the SA node has fired, but before the impulses have traveled to the AV node and activated it. this adds the end diastolic volume to the ventricle (fills it), preloading the ventricle and causing sarcomere stretching |
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Term
| what happens once the AV node has been activated? |
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Definition
| the impulse moves to the bundle of His and perkinje fibers |
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Term
| how long should the PR interval be? QRS complex? |
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Definition
| PR interval: 5 boxes or .2 sec. QRS complex: 3 boxes wide or .12 sec |
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Term
| what does the ST interval represent? |
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Definition
| ventricular repolarization, should be flat |
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Term
| what is important about the QT interval in terms of tx? |
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Definition
| certain drugs can change the ion fluxes in control of this and prolong it - which may leave room for another stimulus which could cause the heart to go into an abberant rhythm, resulting in death |
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Term
| what does it mean for an EKG to be isoelectric? |
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Definition
| it should all be on the same plane |
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Term
| what can an EKG tell you? |
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Definition
| if intervals are normal, if any interventricular conduction is delayed, if there is any blockage, if potassium/calcium is high |
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Term
| what direction should the heart be depolarizing in? |
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Definition
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Term
| what does a positive impulse towards a postive lead read as? |
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Definition
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Term
| what does a positive impulse going away from a positive lead read as? |
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Definition
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Term
| what does an impulse going toward a positive electrode and then past it read as? |
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Definition
| a positive then negative deflection |
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Term
| what is electrical alternans? |
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Definition
| there maybe fluid in the pericardium of the heart that affects the parameters of the EKG b/c the heart may be moving |
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Term
| how much time does a little box on an EKG print out represent? |
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Definition
| .04 sec (x3 = .12 sec for QRS) or 1 mm |
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Term
| what is the calibration standard for EKG printouts? |
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Definition
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