Terminology for Electrocardiography Part I & Part II

Question 1

Aberrancy/Aberrant conduction

Answer 1

abnormal pathway 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

complex containing both an upward and a downward deflection; usually seen when the electrical current is perpendicular to the observed lead

Question 5

Bradycardia (aka sinus bradycardia)

Answer 5

a sinus beat below 60 bpm and a regular rhythm

Question 6

Chronotropy

Answer 6

neural, chemical, or physical factors that influences heart rate; positive chronotropic factors increase HR, while negative chronotropic factors decrease HR (refer to Marieb A&P book for further info)

Question 7

Conductivity

Answer 7

ability of one cardiac cell to transmit an electrical impulse to another cell

Question 8

Depolarization

Answer 8

response of a myocardial cell to an electrical impulse that causes movement of ions across the cell membrane, which triggers myocardial contraction

Question 9

Deviation

Answer 9

major direction of the overall electrical activity of the heart. It can be normal, leftward (left axis deviation, or LAD), rightward (right axis deviation, or 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 10

Dromotropy

Answer 10

agent that affects the conduction speed of the AV node and subsequently the rate of electrical impulse; positive dromotropic agent increases velocity while a negative dromotropic agent decreases velocity

Question 11

Escape rhythm

Answer 11

a self-generated electrical discharge 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 12

Ectopic beat

Answer 12

contraction that occurs as a result of an impulse generated from a site other than the sinoatrial node

Question 13

Excitability

Answer 13

ability of a cardiac cell to respond to an electrical stimulus

Question 14

Hypertrophy

Answer 14

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

Question 15

Infarction

Answer 15

tissue death due to inadequate blood supply to the tissue

Question 16

Inotropy

Answer 16

chemicals that influence contractility of the heart; positive inotropic agents increase contractility while negative inotropic agents decrease contractility (refer to Marieb A&P book for further info)

Question 17

Interval

Answer 17

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

Question 18

Intrinsic/inherent

Answer 18

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

Question 19

Ischemia

Answer 19

local decrease in blood supply

Question 20

Monomorphic

Answer 20

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

Question 21

Multifocal/multiform

Answer 21

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

Question 22

Paroxysmal

Answer 22

episode of an arrhythmia that starts and stops suddenly

Question 23

Polymorphic

Answer 23

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

Question 24

Pre-excitation

Answer 24

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

Question 25

Reciprocal leads

Answer 25

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

Question 26

Re-entry mechanism

Answer 26

failure of a cardiac impulse to follow the normal conduction pathway; instead it follows a circular path

Question 27

Refractory period

Answer 27

brief period during which excitability in a myocardial cell is depressed

Question 28

Repolarization

Answer 28

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

Question 29

Segment

Answer 29

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

Question 30

Tachycardia (aka sinus tachycardia)

Answer 30

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

Question 31

Threshold

Answer 31

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