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40 Cards in this Set
- Front
- Back
what is an ECG?
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electrocardiogram
-recording of cardiac electrical activity from electrodes placed on body surface. |
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how is an ECG plotted?
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voltage versus time.
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what are the electrodes in an ECG essentially?
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electrical dipoles
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what are elect. diples?
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two conductors with app. equal charge magnitude but opposite direction. located in close proximity to ea. other
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what 2 characteristics about the dipole determine voltage diffnc measured in an ECG?
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-magnitude of charge difference
-placement of electrodes |
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what does ECG detect?
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changes in the polarity of the membrane -> when it depolarizes compared to a nondepolarized section of membrane.
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what is a common triangle used for connecting leads in an ECG?
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Einthoven triangle
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where are the three leads connected in an einthoven triangle?
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1. Left arm/right arm
2. Left leg/right arm 3. Left leg/left arm |
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what does upward deflection on an ECG tell?
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that a positive dipole has been conducted in that lead.
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What is Einthoven's triangle useful for?
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determining the mean electrical axis of a heart - indicates if problem in conduction, depolarization, or repolariz of myocardium.
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What are the components of the ECG wave?
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P wave
QRS wave T wave |
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what is the p wave?
-qrs? -t? |
P = atrial depolarization
QRS = ventric depolarization T = ventric repolarization |
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what is the PR interval?
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time required for depolarization to travel from SA to ventricle.
-measures VA node health |
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What is the ST segment?
-when is it elevated? -when is it depressed? |
an isoelectric period.
-elevated in Myocardial infarct. -depressed in angina. |
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What is represented by the duration of the QRS wave?
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the time necess to depolarize ventricles - shows health of conducting system.
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What do you know from the
-RR interval -PP interval? |
RR = indication of ventric rate
PP = indication of atrial rate |
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what are 4 types of ECG abnormalities?
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1. Arrythmia
2. Long QT syndrome 3. Atrial PRemature Complex 4. Ventricular Premature complex |
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what is arrythmia?
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a disorder of Cardiac rate and rythm.
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what is Long QT syndrome?
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-Time btwn ventric depolariz and repolariz is longer than normal.
-due to prolonged repolarization |
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what symptom does long qt syndrome cause?
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-fibrillation, bag of worms moveent.
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What are APCs?
What causes them? |
-Atrial premature complexes, -Early P waves arising from any part of the atria.
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What are VPCs?
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Ventricular Premature complexes.
-QRS complexes without a preceding P wave. |
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Who are APCs and VPCs seen in?
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present in over 60%, but usually asymptomatic.
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what are four types of AV block?
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1st, 2nd, 3rd, and 4th degree.
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what is 1st degree AV block?
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normal conduction of P waves to ventricles, but slowed conduction through AV node.
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what is 2nd degree AV block?
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Incomplete coupling of AV and ventricles; some P waves are missed by the ventricles.
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What is a name for 2nd degree AV block type one?
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wenckebach's
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what is the symptom of wenckebach's AV block?
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PR interval is increased until there is a missed beat.
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what is 2nd degree AV block, type II?
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Mobitz syndrome. the PR interval is long, but not random -> CONSTANT. Every Nth T is missing.
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What occurs in type III av node block?
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complete dissoc. of AV node and ventricles; no impulse conduction.
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How does Myocardial Infarction affect the ST segment?
Why? |
Depresses it; because ischemic injury is worse farther away from the coronary vessels.
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How does Angina pectoralis affect the ST segment?
Why? |
Elevates it. Because angina ischemia involves the whole wall of the myocardium.
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What characterizes QT syndrome?
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-A congenital or drug-ind state.
-Prolonged ventricular repolarization lengthens QT int. -Causes susceptibility to fibrillation, instant death. |
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What are
-Atrial premature complexes? -Ventric premature compexes? |
early atrial P waves
early ventricular QRS waves, not preceded by a P wave. |
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What is atrial fibrillation?
What is atrial flutter? |
-Atrial activity that may not be evident.
-Regular and inappropriately rapid atrial activity |
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what is AV block?
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blockage to elect. conduction through the AV node.
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What is 1st degree block?
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not full blockage, just slowed conduction.
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what is 2nd degree block?
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incomplete coupling - some P waves don't conduct from AV node to ventricles.
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what is 3rd degree block?
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Full blockage; AV node excitation is decoupled from ventricular
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what are two types of 2nd degree block?
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-Wenckebach: PR interval is so long that conduction fails. Occurs in AV node.
-Mobitz: PR interval is long, but every nth T wave is missing. Occurs in Bundle branches. |