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EKG II
CVM
16
Medical
Graduate
03/11/2010

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Cards

Term
where is the SA node? what part of the EKG is it responsible for?
Definition
the SA node sits on the posterior wall of the RA and is constantly releasing an electrical signal - the P wave
Term
what is the Q wave?
Definition
the first downward deflection (must be deep and wide to be significant, which could indicate an MI)
Term
what is the PR interval? what does it do?
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
Term
what happens once the AV node has been activated?
Definition
the impulse moves to the bundle of His and perkinje fibers
Term
how long should the PR interval be? QRS complex?
Definition
PR interval: 5 boxes or .2 sec. QRS complex: 3 boxes wide or .12 sec
Term
what does the ST interval represent?
Definition
ventricular repolarization, should be flat
Term
what is important about the QT interval in terms of tx?
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
Term
what does it mean for an EKG to be isoelectric?
Definition
it should all be on the same plane
Term
what can an EKG tell you?
Definition
if intervals are normal, if any interventricular conduction is delayed, if there is any blockage, if potassium/calcium is high
Term
what direction should the heart be depolarizing in?
Definition
0 -> 90 degrees
Term
what does a positive impulse towards a postive lead read as?
Definition
positive deflection
Term
what does a positive impulse going away from a positive lead read as?
Definition
negative deflection
Term
what does an impulse going toward a positive electrode and then past it read as?
Definition
a positive then negative deflection
Term
what is electrical alternans?
Definition
there maybe fluid in the pericardium of the heart that affects the parameters of the EKG b/c the heart may be moving
Term
how much time does a little box on an EKG print out represent?
Definition
.04 sec (x3 = .12 sec for QRS) or 1 mm
Term
what is the calibration standard for EKG printouts?
Definition
10 mm = 1 mV
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