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EKG > Dubin's Week 1: pgs 1-93 > Flashcards

Dubin's Week 1: pgs 1-93 Flashcards

(58 cards)

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1
Q

1970 Luigi Galvani

A

made a dead frog’s legs move by connecting opposite charges to stimulate an electrical current

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2
Q

1855 Kollicker + Mueller

A

found that when a motor nerve to a frog’s leg was laid over it’s isolated beating heart, the leg kicked

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3
Q

mid 1880’s Lugwig + Waller

A

discovered that the heart’s rhythmic electrical stimuli could be omintored from a person’s skin

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4
Q

Dr. William Einthoven

A

found that electrodes on skin connected to the ends of a silvered wire ran between poles of a magnet twitched with the person’s heartbeat
-wire movements were recorded as waves (P, QRS, T)

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5
Q

EKG

A

records electrical activity of contraction of the heart muscle
-provides information regarding function and structure

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6
Q

Resting state, myocytes are ____ and ____ charged

A

polarized and negatively charged

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7
Q

When depolarized, myocytes become ____ and ____

A

positive and contract

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8
Q

Depolarization begins in the ____ and spreads to…

A

right atrium and spreads to left atrium then interventricular septum and ventricles

stimulates atria to contract

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9
Q

During repolarization, myocytes regain their ____ charge

A

negative

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10
Q

As the positive wave of depolarization flows towards a positive electrode, there is a ____ deflection on the EKG

A

positive

by Na+ ions

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11
Q

SA node

A

dominant pacemaker with automaticity
-located in upper posterior wall of right atrium

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12
Q

Automaticity foci

A

focal areas of the heart that also have automaticity

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13
Q

P Wave

A

represents atrial depolarization emitted by SA node (and contraction)

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14
Q

AV Valves

A

prevent backflow and electrically insulate the ventricles from the atria
-except for AV node

mitral and tricuspid

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15
Q

Wave of depolarization entering AV node

pause / flat baseline following P wave

A

allows time for blood in atria to enter ventricles (carried by Ca2+ ions)

SLOW

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16
Q

Depolarization is rapid through …

A

Bundle of HIS and L + R bundle branches (purkinje fibers)

Fast Na+ ions

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17
Q

QRS Complex

A

rapid ventricular depolarization (and contraction)

fast moving Na+ ions for conduction

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18
Q

Q wave

A

often absent on EKG

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19
Q

ST segment

A

represents initial ventricular repolarization
-ST elevation or depression = pathology

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20
Q

T wave

A

represent final rapid phase of ventricular repolarization

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21
Q

Repolarization (ST seg + T wave) is accomplished by

A

K+ ions leaving the myocytes

re-establish negative charge to prepare for depolarization

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22
Q

Ventricular systole on EKG

A

begins with QRS and spans until the end of the T wave

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23
Q

QT interval

A

represents ventricular systole
-good indicator of repolarization
-long QT interval = rapid ventricular rhythms
-normal = when QRS is less than half of R to R interval at normal rates

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24
Q

Measure of voltage

Study These Flashcards
A

height and depth (amplitude) of a wave measured from baseline in millimeters

25
Deflection of wave
direction which it records on EKG (up or down)
26
Amount of time represented by 2 heavy black lines
0.2 of a second
27
Amount of time represented by each small sqaure division
0.04 of a second
28
Four small squares = ____ of a second
0.16 of a second | 0.04 x 4 = 0.16
29
Limb leads | "bipolar"
1, 2, 3, AVR, AVL, AVF -each consists of one positive and one negative electrode ## Footnote frontal plane
30
Chest leads
V1, V2, V3, V4, V5, V6 | oriented through AV node and project through pt's back (negative) ## Footnote horizontal plane
31
Lead 1 ## Footnote Limb leads
left arm electrode = positive right arm electrode = negative | horizontal
32
Lead 3 ## Footnote Limb leads
left arm electrode = negative left leg electrode = positive
33
Einthoven's triangle
bipolar limb lead configuration
34
AVF lead ## Footnote Limb leads
**combination of leads 2 + 3** -left foot electrode = positive -both arm electrodes = negative | Augmented Voltage (left) Foot
35
AVR lead ## Footnote Limb leads
**R = R arm positive** -right arm electrode = positive -remaining 2 electrodes = negative
36
AVL lead ## Footnote Limb leads
**L = L arm positive** -left arm electrode = positive -remaining 2 electrodes = negative
37
Augmented "unipolar" limb leads
**AVR, AVF, AVL** -intersect at 60 degree angles + split the angles formed by leads 1, 2, 3
38
Positive arm electrode is used to record ## Footnote Limb leads
lateral leads 1 + AVL
39
Positive foot electrode is used to record ## Footnote Limb leads
inferior leads 2, 3 + AVF
40
Electrodes for chest leads are always
positive
41
In V1, the QRS complex is mainly ___
negative
42
in V6 the QRS complex is mainly ____
**positive** -produced by ventricular depolarization moving towards positive chest electrode V6
43
ANS function
**main concern in autonomic control of the heart + systemic arteries (BP)** -regulates vital functions of all organs by reflex and CNS
44
Sympathetic NS ## Footnote ANS
**secretes N.E. + delivers to B1 adrenergic receptors** -stimulates SA node to pace faster -improves AV node conduction -accelerates conduction through atrial/ventricular myocardium -increases force of myocardial contraction -increases irritability of atrial and junctional automaticity foci -epinephrine secreted into blood by adrenal glands -constricts arteries = increased BP and flow of blood (by N.E.) | stimulation
45
Parasympathetic NS ## Footnote ANS
**vagal nerve stimulation; secretes ACH + acts upon cholinergic receptors (mostly within atria)** -inhibts SA node (decr. HR) -decreases speed of contraction -depresses AV node -depresses irritability of automaticity on atria and AV junctional foci -dilates arteries = reduces BP and flow of blood | inhibitory BUT stimulates G.I. tract
46
Syncope
**reflex parasympathetic response resulting in LOC** -slows SA node pacing (bradycardia) -same response causes hypotension -reduces brain's blood supply
47
Sympathetic response to standing
**pressure baroreceptors initiate symp reflex - constriction of peripheral arteries to prevent distal blood pooling** -stimulates sinus pacing -conserve blood flow to the brain -sympathetic vasoconstriction to maintain adequate circulation
48
Orthostatic hypotension
abrupt fall in BP due to failure of compensatory sympathetic mechanism upon standing
49
Neurocardiogenic syncope
**paradoxical parasympathetic response often in elderly causes vasodilation and slowing of the pulse due to prolonged standing** -results in LOC -head up tilt (HUT) test confirms diagnosis
50
Proper interpretation of EKG includes consideration of
rate, rhythm, axis, hypertrophy, infarction
51
Sinus rhythm
produced by SA node 60-100 bpm
52
Automaticity foci
**potential pacemakers in event that the SA node stops functioning** -normally silent unless emergency -only one will assume pacemaking | atrial, junctional, ventricular foci
53
Atrial automaticity foci
inherent rate = at 60-80 bpm | paces if SA node fails
54
Junctional automaticity foci
inherent rate = 40-60 bpm | paces if Sa node + Atrial foci fails
55
Ventricular automaticity foci
inherent rate = 20-40 bpm | paces if SA node, atrial + junctional foci fail
56
Overdrive suppression
**rapid automaticity pacing that suppresses slower automaticity** -characteristic of all foci -eliminates competition from lower foci
57
Calculation of rate | (normal or tachy)
1. look at R wave peaking on heavy black line (=start) 2. count off 300, 150, 100, 75, 60, 50 3. find the next R wave 4. where it falls = rate
58
Calculation of rate | (bradycardia or irregular rhythms)
1. look for small black line trace at top of EKG paper 2. two of those 3 second intervals = 6 seconds 3. count the number of cycles (R wave to R wave) within the 6 seconds 4. multiply number of cycles by 10

EKG (4 decks)

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