ECG I & II Terminology

Question 1

Aberrancy/Aberrant conduction

Answer 1

abnormal pathyway of an impulse traveling through the heart’s conduction system

Question 2

Arrhythmia

Answer 2

disturbance of the normal cardiac rhythm from the abnormal origin, discharge, or conduction of electrical impulses

Question 3

automaticity

Answer 3

ability of cardiac cell to initiate an impulse on its own

Question 4

Biphasic

Answer 4

Having an electrical impulse that is shown as deflections above and below the isoelectric line

Question 5

bradycardia (sinus bradycardia)

Answer 5

a sinus beat below 60 bpm and a regular rhythm

Question 6

chronotropy

Answer 6

neural, chemical, or physical factor that influences heart rate; referring to rate or time, such as the rate of cardiac contraction

Question 7

positive chronotropic agent

Answer 7

increase heart rate

Question 8

negative chronotropic agent

Answer 8

decrease heart rate

Question 9

conductivity

Answer 9

ability of one cardiac cell to transmit and electrical impulse to another cell; the reciprocal of resistivity

Question 10

depolarization

Answer 10

response of a myocardial cell to an electrical impulse that causes movement of ions across the cell membrane, which triggers myocardial contraction; the process or act of reversing the resting potential in excitable cell membranes when stimulated

Question 11

deviation

Answer 11

major direction of the overall electrical activity of the heart. It can be normal, leftward (left axis deviation, or LAD), rightward (right axis deviation; RAD) or indeterminate (northwest axis). The QRS is the most important to determine; however, the P wave or T wave axis can also be measured

Question 12

dromotropy

Answer 12

agent the affects the conduction speed of the AV node and subsequently the rate of electrical impulse; referring to the conductivity of a nerve fiber, such as the ability to conduct through the AV node

Question 13

positive dromotropic agent

Answer 13

increase velocity

Question 14

negative dromotropic agent

Answer 14

decrease velocity

Question 15

escape rhythm

Answer 15

a self-generated electrical dishcarge initiated by, and causing contraction of, the ventricles of the heart; this beat usually follows a long pause in ventricular rhythm and acts to prevent cardiac arrest

Question 16

excitability

Answer 16

ability of a cardiac cell to respond to an electrical stimulus

Question 17

hypertrophy

Answer 17

growth to an organ or tissue due to an increase in the size of the cell

Question 18

infarction

Answer 18

tissue death due to inadequate blood supply to the tissue

Question 19

inotropy

Answer 19

chemicals that influence contractility of the heart

Question 20

positive inotropic agents

Answer 20

increase contractility

Question 21

negative inotropic agents

Answer 21

decrease cotractility

Question 22

intrinsic/inherent

Answer 22

naturally occurring electrical stimulus from within the heart’s conduction system

Question 23

interval

Answer 23

duration of time that includes one segment and one or more waves

Question 24

ischemia

Answer 24

local decrease in blood supply

Question 25

monomorphic

Answer 25

form of ventricular tachycardia in which the QRS complexes have a uniform appearance from beat to beat

Question 26

multifocal/multiform

Answer 26

type of premature ventricular contractions that have differing QRS configurations as a result of their originating from different irritable site in the ventricle

Question 27

paroxysmal

Answer 27

episode of an arrhythmia that starts and stops suddenly

Question 28

polymorphic

Answer 28

type of ventricular tachycardia in which the QRS complexes change from beat to beat

Question 29

reciprocal leads

Answer 29

leads that take a view of an infarcted area of the heart opposite that taken by indicative leads

Question 30

pre-excitation

Answer 30

an abnormal heart rhythm in which the ventricles of the heart become depolarized too early, which leads to their partial premature contraction

Question 31

refractory period

Answer 31

brief period during which excitability in a myocardial cell is depressed

Question 32

repolarization

Answer 32

recovery of the myocardial cells after depolarization during which the cell membrane returns to its resting potential; the return of cell membrane potential to the resting state

Question 33

tachycardia (aka sinus tachycardia)

Answer 33

a sinus rate of more than 100 bpm. The rate rarely exceeds 160 bpm except during exercise

Question 34

Threshold

Answer 34

the minimum level to which a membrane potential must be depolarized to initiate an action potential

Question 35

segment

Answer 35

part of the ECG between the QRS complex and the T wave