1. Chapter 10 Excitation of the hearth and Cardiac conduction

Question 1

Name the normal impulse conduction pathway

Answer 1

SA Node–> AV Node –> AV bundle –> R&L bundle branches –> Purkinje fibers

Question 2

Where is there a delay seen in the impulse transmission

Answer 2

AV delay

Question 3

____ pacemaker is located somewhere other than the SA node and causes an abnormal seq of events as noted on an ECG

Answer 3

ectopic pacemaker

Question 4

SA node has an intrinsic rate of ___ beats/min

Answer 4

70-80

Question 5

AV node has an intrinsic rate of ____ beats/ min

Answer 5

40-60

Question 6

Purkinje fibers have an intrinsic rate of ____ beats/ min

Answer 6

15-40

Question 7

PS stim comes from (3) factors

Answer 7

Vagus N
AcH
Innervates SA and AV

Question 8

SP stim comes from (3) factors

Answer 8

NE

incr. rate of conduction
incr. force of contraction

Question 9

P wave reps ______

Answer 9

atrial depolarization

Question 10

QRS compex reps_______

Answer 10

ventricular depolarization

Question 11

T wave reps ______

Answer 11

ventricular repolarization

Question 12

On an ECG paper what are the units for the vertical reading and horizontal reading

Answer 12

horizontal: sec
Vertical: mV

Question 13

QT interval represents

Answer 13

ventrical depaolarization and repolarization

from right before the Q dip to after the T hump

Question 14

before stim the external cells of the M are ___ charged and the internal cells are ___ charged

Answer 14

ext= pos. 
int= neg 

• when it becomes depolarized, Neg charges leak to the outside making it neg

Question 15

____node triggers cardiac impulse

Answer 15

SA node

aka Sinus node

Question 16

Bradycardia is HR at _____bpm

Answer 16

<60 bpm

Question 17

c.c. __________sx: baroreceptors in carotid sinus are super sensitive and mild pressure on neck has baro. reflex

Answer 17

carotid sinus sx

Question 18

carotid sinus sx _______ in carotid sinus are sensitive and slow down HR

Answer 18

baroreceptors

Question 19

baroceptor reflex will cause an increase in _____ stim

Answer 19

vagal

Question 20

tachycardia has a bpm of ____

Answer 20

> 100bpm

Question 21

Catachycardia is a cause of ____ reflex to increase HR to pump more blood out

Answer 21

SP reflex

Question 22

c.c. ___ arrhythmia that is influenced by parallel vagus N activity during breathing

Answer 22

Sinus arrhythmia

• characterized by irregular distance btw T wave and P wave

Question 23

Name (3) abnormal sinus arrhythmias

Answer 23

1. sinus bradycardia
2. tachycardia
3. sinus arrythmia

Question 24

Name the (4) arrhythmias from block of impulse within conduction pathway

Answer 24

1. sinoatrial block
2. first degree heart block
3. second degree “ “
4. third degree block (complete AV block)

Question 25

c.c._____ the impulse is blocked before it enters the R atria so no P wave present .

Answer 25

sinoatrial block - AV node becomes pacemaker - QRS are evient but slow

Question 26

c.c_____ condition where the AV node becomes the pacemaker. There is no P wave

Answer 26

Sinoatrial block - QRS are eviedent but slow

Question 27

_____degree heart block is when the P-R interval is >0.2

Answer 27

First degree heart block | - incomplete heart block bc the signal is delayed rather than totally blocked

Question 28

c.c.______ causes inflammation of the AV node. This condition can cause first degree heart block

Answer 28

acute rheumatic heart disease

Question 29

What is a "dropped beat"

Answer 29

absence of a QRS & T wave

Question 30

c.c.___ when the P-R interval is 0.25-0.45

Answer 30

Second degree heart block. - some impulses pass through the AV bundle but others do not causing "dropped beats"

Question 31

c.c.___ block: complete lack of synchronization btw atria and ventricles

Answer 31

complete AV block - PP interval consistent - QRS & T is dissociated

Question 32

c.c.____ block complete AV block

Answer 32

third degree block

Question 33

c.c ___sx is a complete AV block that comes and goes. Causes fainting

Answer 33

Stokes adams syndrome

Question 34

tx for stokes adams sx

Answer 34

pacemaker to R ventricle

Question 35

_______ ventricules excitability is suppressed bc ventricles have been driven at rate greater than natural rhythm (stokes adams sx)

Answer 35

over drive suppression

Question 36

______: occurs woth an AV node or AV bundle stim (15-40bpm) since there is a block in the SA node (stokes adams sx)

Answer 36

ventricular escape

Question 37

premature contractions are a results of ____

Answer 37

ectopic foci

Question 38

Name (4) causes of ectopic foci

Answer 38

1. local areas of ischemia 2. irritation of cardiac M 3. toxic irritation from drugs, caffeine, or nicotine 4. mech initiation of PVC during catheterization of R ventricle

Question 39

pulse deficit can occur in PACs bc ____do not fill so SV decr.

Answer 39

ventricles

Question 40

re-entrant pathway occurs when an impulse ___ and results in a self perpetuating impulse formation

Answer 40

loops - can cause atrial flutter

Question 41

______: the affected atria contracting at a rate of 200-350 bpm bc of re-entry wave

Answer 41

atrial flutter - not all ventricles are stim. QRS every few

Question 42

_____: activation of atria is irregular and CHAOTIC so atria bc useless

Answer 42

atrial fibrillation - cause: atrial hypertrophy

Question 43

____: premature contraction originate in one of the jxns

Answer 43

jxn rhythms - P wave occurs late so it occurs in QRS - distorts QRS, inverts it

Question 44

____: P wave travels backward into atria | In Jxn rhythms

Answer 44

retrograde direction

Question 45

_________: condition where QRS has abnormal form bc one side depolarizes ahead of the other. T wave is inverted

Answer 45

Premature Ventricular contractions (PVCs)

Question 46

c.c______: ventricules are stim to contract at 120bpm. re-entrant stim leads to circular activation

Answer 46

ventricular tachycardia (V-tach) - cause by ischemia or myocardial infraction

Question 47

c.c.______: ventricular depolarization occurs CHAOTICALLY so some parts contract while others are relaxed so little blood pumped out of heart

Answer 47

Ventricular Fibrillation (V-Fib )