EKG Basic Principles

Question 1

info on EKG represents heart’s ____ activity

Answer 1

electrical

Question 2

most information on EKG represents electrical activity of ____ of myocardium

Answer 2

contraction

Question 3

when myocardium is electrically stimulated, it ____

Answer 3

contracts

Question 4

while in the resting state, myocytes are POLARIZED, the interior of every cell are ____-ly charged

Answer 4

negative

Question 5

the interiors of resting myocytes are NEGATIVE, but when these cells are DEPOLARIZED, their interiors become ____ and the cells contract

Answer 5

positive

Question 6

“depolarization” moves as a wave through the myocardium; as this wave of DEPOLARIZATION stimulates the heart’s myocytes, they become positive and ____

Answer 6

contract

Question 7

depolarization may be considered an advancing wave of ____ charges w/i the heart’s myocytes

Answer 7

positive

Question 8

advancing wave of depolarization causes progressive contraction of myocardium as this wave of ____ charges passes through the interiors of myocytes

Answer 8

positive

Question 9

stimulating wave of depolarization makes the interiors of myocytes ____ and stimulates them to contract

Answer 9

positive

Question 10

myocyte interiors regain their resting negative charge during the ____ phase that follows

Answer 10

repolarization

Question 11

myocardial contraction is caused by ____ of myocytes, which records on on the EKG as shown above; the recovery phase that follows depolarization is known as ____

Answer 11

depolarization

repolarization

Question 12

both depolarization and repolarization of the myocardium are ____ phenomena caused by movement of ions

Answer 12

electrical

Question 13

a wave of depolarization advancing through myocardium is a moving wave of ____ charges

Answer 13

positive

Question 14

when a wave of POSITIVE charges (Na+ ions) moves TOWARDS a POSITIVE electrode, there is a simultaneous ____ deflection

Answer 14

UPWARD

Question 15

heart’s dominant pacemaker

Answer 15

SA node

Question 16

SA node location

Answer 16

upper-posterior wall of right atrium

Question 17

SA node stimulates both atria to ____

Answer 17

contract

Question 18

ability of SA node to generate pacemaking stimuli is known as ____

Answer 18

automaticity

Question 19

atrial depolarization is recorded as a ____ wave on EKG

Answer 19

P

Question 20

P wave represents

Answer 20

atrial depolarization

Question 21

sole electrical pathway from atria to ventricles

Answer 21

AV node

Question 22

mitral and tricuspid valves act to electrically ____ the ventricles from the atria

Answer 22

insulate

Question 23

because depolarization slows w/i the AV node, there is a brief ____ before depolarization is conducted to the ventricles

Answer 23

pause

Question 24

brief pause allows blood from atria to pass the AV valves and into the ____

Answer 24

ventricles

Question 25

depolarization shoots rapidly through the ventricular conduction system beginning in the ____

Answer 25

His bundle

Question 26

His bundle splits into ____

Answer 26

left and right branches

Question 27

His bundle and both bundle branches are “bundles” of ____

Answer 27

rapidly conducting Purkinje fibers

Question 28

like myocardium, Purkinje fibers use fast-moving ____ for the conduction of depolarization

Answer 28

Na+ ions

Question 29

Purkinje fibers terminate in tiny filaments that directly ____ the ventricular myocytes

Answer 29

depolarize

Question 30

____ represents the beginning of ventricular contraction

Answer 30

QRS complex

Question 31

first downward deflection of QRS complex

Answer 31

Q wave

Question 32

Q wave can often be ____ on EKG

Answer 32

absent

Question 33

Q wave is followed by upward ____

Answer 33

R wave

Question 34

upward R wave is followed by downward ____

Answer 34

S wave

Question 35

horizontal segment of baseline following QRS complex

Answer 35

ST segment

Question 36

ST segment represents

Answer 36

initial (“plateau”) phase of ventricular repolarization

Question 37

T wave represents

Answer 37

final (“rapid”) phase of ventricular repolarization

Question 38

repolarization (both, initial and final, phases) is accomplished by ____ leaving the myocytes

Answer 38

K+ ions

Question 39

ventricular systole lasts from ____ until

Answer 39

beginning of QRS

end of T wave

Question 40

represents the duration of ventricular systole

Answer 40

QT interval