NBS Exam 1 Flashcards

1
Q

normal length of the PR interval

A

.12 - .2 seconds

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2
Q

normal length of QRS complex

A

less than .1 seconds

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3
Q

if QRS is wide

A

you think of conduction problems int he ventricles

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4
Q

The MEA (mean electrical axis) of ventricular depolarization should be between

A

-30 and +120 degrees

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5
Q

definitiion of right axis deviation

A

+120-+180

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6
Q

definition of left axis devition

A

-30–90

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7
Q

causes of left axis deviation

A

LV hypertrophy, left bundle branch block, high diaphragm due to obesity, pregnncy or ascites, or a right sided infarct.

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8
Q

MEA shifts towrds ____ and away from ___

A

towards hypertrophy and away from infarction

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9
Q

causes of Right axis deviation

A

RV hypoertrophy, right bundle branch block , flat diaphragm, due to being thin, left side infarct

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10
Q

What is 1st degree block?

A

1st degree block is when there is a delay in impulse conduction at the level of the AV node leading to a prolonged PR segment

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11
Q

how do you diagnose 1st degree block

A

the PR segment will be >.2 seconds

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12
Q

What are some causes of 1st degree block

A

calcium channel blockers, bta blockers or increased Ach tone

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13
Q

What is second degree block: Mobitz type I

A

When every so often there is a P wave with no QRS following it, with progressively lenghtening PR segments up to that.

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14
Q

What is second degree block: Mobitz type I due to?

A

due to a block at the AV node from increased parasympathetic tone or a cardiosupressant drug

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15
Q

What is second degree block: Mobitz type II due to

A

anterior wall infarct where blockage occurs below the level of the AV, usually at the bundle branch

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16
Q

How do you diagnose second degree block: Mobitz type II

A

can be seen to frequently drop a QRS segment without PR lengthening prior to the dropped beat

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17
Q

What is third degree block?

A

When there is a complete block at the AV node so there is no coordination between the contraction of the atria and the ventricles. The PP and RR segments are normal but they are not coordianted. The ventricle takes on its own pacemaker

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18
Q

What determines the width of the QRS complex in third degree heart block?

A

How far the pacemaker is from the AV node. The farther from the AV node, the wider the QRS

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19
Q

Bundle Branch Block is seen on an ECG as?

A

an R and R’ wave. Where one ventricle contract normally to give the R wave and the ventricle with the damaged bundle branch conducts slower in cell:cell conduction to give an R’ wave

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20
Q

what is Delta Wave (Wolff-Parkinson-White Syndrome)

A

There is an accessory pathway of muscle cells that bypass’ the AV node so you do not get the normal delay

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21
Q

How does Wolff-parkinson0white syndomre look on EKG

A

have a delta wave where the PR segment has a positive slope (due to the early depolarization of the ventricles)

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22
Q

Atrial fibrillation is caused by what

A

when the tissue at the base of the pumlonary vein in the right atria becomes very excitable and will send impulses to the AV node. This results in asynchronous contraction of the atrial muscle and loss of the atrial kick during ventricular filling

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23
Q

What does atrial fibrillation look like on an EKG

A
  • The atrial rate is increased and ventricular rate is variable, ventricular rhythym is variable.
  • no identifiable P-waves with no measurable PR interval
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24
Q

What causes ventricular tachycardia

A

have fast Na channels on the ventricle that are randomly depolarizing: but if you have a depolarization at the wrong time during repolarization (during T-wave), you can end up initiating another action potential
-the SA node is no longer in control

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25
What is R on T phenomenon
on T phenomenon: an ectopic beat during relative refractory period asynchronous contraction of ventricle
26
how to you treat Vtach
using a sodium channel blocker
27
The right coronoary artery perfuses
- the Rt atrium and rt ventricle - the inferior and posterior L ventricle - the SA and AV node - the bundle of his
28
The LAD perfuses
the anterior Left ventricle, the IV septum, the RBB and the anterior LBB
29
The circumflex coronary artery perfsues
the left atrium, lateral left venticle, some of the SA and AV node sometimes
30
leads for looking at the Right coronary artery ishcemia
II, III, aVF
31
Leads for looking @ the left anterior descending artery ischemia
V1, V2, V3 and V4
32
Leads for looking at the cifcumflex coronary artery ischemia
I, aVL, V5 and V6
33
normal pressure in the right atrium
0-8
34
normal pressure in the right ventricle
diastole: 0-5 systole: 15-30
35
normal pressures in the pulmonary artery
systolic: 15-30 diastolic: 5-15
36
left atrium normal pressure
4-12
37
left ventricular normal pressure
diastolic 4-12 | systolic 90-140
38
normal pressues in the aorta
diastolic: 60-90 systolic: 90-140
39
What is the a wave
the a wave is the contraction of the atria that results in increased pressure in the atria and ventricle since the mitral valve is open
40
S4 hert sound is due to
during atrial contraction when blood it being quickly rushed into the ventricles. If you hear this sound, it is pathologic and means that there is likely fibrosis of the ventricle.
41
S1 is due to
the closure of the mitral valve
42
what is the c wave?
the wave is the increase in pressure in the atria due to the balooning of the AV valve into it during isovolumic contraction
43
what is happening during the ST phase in terms of cardiac cycle?
rapid ejection phase
44
the beginning of the T-wave corresponds with
the onset of the reduced ejection phase
45
wht is S2 sound
This is the aortic valve closing. The lower pressure in the ventricle than the atria causes the blood to rush backwards and slam against the closed vavle
46
what is the v wave
this is the increase in P in the atria due to the mitral valve being closed but blood entering it from the IVC and SVC
47
what is S3 heart sound
is when the mitral valve opens and blood rushes into the ventricle. Due to reduced compliance of the ventricular wall in athletes. not always pathalogical
48
what is a canon wave
You have one big A and C wave in the atria instead of separate. The a wave is very high due to high pressure generated by the right ventricle.
49
why do you get canon waves?
You get canon waves in stenosis of the tricuspid valve. since the atria has to pump so much harder, Can also see hem in 3rd degree heart block if the atrial depolarization occurs during ventricular systole
50
how would one diagnose tricuspid valve insufficiency
Large C-V waves throughout the right ventricular contraction due to blood being pumped back into the right atrium and jugular vein rather than forward to the pulmonary artery. They occur directly after ventricular systole begins
51
normal CO
3.5-5 L/min
52
calcualing cardiac index
CO/ body surface (2.4-3.5)
53
equation for CO
O2 consumption/ arterial-venous difference in O2
54
effect and use of NE
NE has noth alpha and beta effects--> indicated for hemodynamic hypotension or cardiogenic shock
55
Effects and use of Epi
has both beta and alpha effects--> indaicted for cardiac arrest
56
effects and use of dobutamine
only B effects. a postitive inotrope with very little chronotropic effects. increases contracitlity w.o increasing HR much (there is a baroreceptor reflex that actually decreases the HR and undoes the slight increase from dobutamine)
57
effects and use of Nitroglycerin
dilates the coronary arteries improving the persufion of ischemic myocardium
58
effects and use of nitroprusside
peripheral vasodilator affecting both arterial and venous system. Use when reduction of afterload is necessary
59
cardiac glycosides
inhibit the Na/K pump to increase extracellular Na.The increase in extracellular Na blocks the Ca/Na exchanger which pumps Na in and Ca out. This gives you more Ca in the cell and acts as a positive inotrop
60
von wiebel bodies
are the storage granules of endothelial cells, the cells that form the inner lining of the blood vessels and heart. They store and release two principal molecules, von Willebrand factor and P-selectin, and thus play a dual role in hemostasis and inflammation.
61
the basal lamina of fenestrated capillaries is
continuous
62
peripheral chemoreceptors are most sensitive to
PO2 and CO2
63
Central chemoreceptors are most sensitive to
H+ concentration
64
btw chemoreceptors and baroreceptors which wins?
baro
65
when there is atrial stretch what occurs
decreased SNS to the kidney to increase GFR and increased SNS to AV and SA node to increase HR
66
histamine is a systemic vaso___ and a pulmoary vaso___
systemic vasidillator pulomary constrictor
67
what dictates control of the brain
Co2 and O2
68
When you see a q stem w coronary blood flow think:
Work = P*V=MAP*SV