The ST segment is measured from:
The end of the QRS complex to the beginning of the T wave.
Five large boxes, each consisting of five small boxes, represent ____ on ECG paper?
1 second
Which part of the conduction system receives an impulse from the SA node but delays relaying that impulse to the bundle of His, allowing time for the atria to empty their contents into the ventricles before the onset of ventricular contraction?
AV node
On the ECG, total supraventricular activity is reflected by the______
PR interval
In an adult, the normal duration of the QRS complex is
0.11 second or less
The main electrolytes that affect cardiac function are
sodium, potassium, calcium, and chloride
The portion of the ECG tracing used to determine the degree of ST segment displacement is
TP segment
In the normal heart, the primary pacemaker is the?
SA node
Which of the following surfaces of the heart are not directly viewed when using a standard 12-lead ECG?
Right ventricle and posterior surface of the left ventricle
U waves represent
repolarization of the Purkinje fibers
_______ cells are specialized cells of the electrical conduction system responsible for the spontaneous generation and conduction of electrical impulses
Pacemaker
Where is the positive electrode placed in lead III?
left leg or foot
When an ECG machine is properly calibrated, a 1-mV electrical signal will produce a deflection measuring exactly ________ tall.
10mm
Which of the following are horizontal plane leads?
V1, V2, V3, V4, V5, V6 (all chest leads)
This type of action potential occurs in the SA and AV nodes
slow response
A chain reaction that occurs from cell to cell in the heart's electrical conduction system until all the cells have been stimulated
wave of depolarization
The movement of charged particles across a cell membrane in which the inside of the cell is restored to its negative charge
repolarization
Examples of antiarrhythmics that block sodium channels
procainamide and lidocaine
The rapid sequence of voltage changes that occur across the cell membrane during the electrical cardiac cycle
action potential
this type of action potential occurs in normal atrial and ventricular myocardial cells and in the purkinje fibers
fast response
The movement of ions across a cell membrane causing the inside of the cell to become more positive
depolarization
Examples of antiarrhythmics that slow the rate at which calcium passes through the cells
verapamil and diltiazem
Which is NOT a use for ECG monitoring?
a. to monitor a patient's heart rate
b. to evaluate pacemaker function
c. to monitor a patient's blood pressure
d. to evaluate for signs of myocardial injury
C
Which of the following is NOT a property of cardiac cells?
a. automaticity
b. excitability
c. conductivity
d. relaxability
e. contractility
D