Core Concepts In Pharmacology Ch 16

Front 1

action potential

Back 1

change in electrical activity across the plasma membrane of a muscle or nerve cell

caused by changes in membrane permeability (stimulus)

Front 2

atrioventricular bundle

Back 2

specialized cardiac tissue that receives electrical impulses from the AV node and sends them to the bundle branches (Bundle of His)

AV Node -> AV Bundle -> Bundle of His

Front 3

atrioventricular (AV) node

Back 3

mass of cardiac tissue that receives electrical impulses from the SA node and conveys them to the ventricles

SA Node -> AV Node -> Ventricles

Front 4

automaticity

Back 4

ability to spontaneously generate an electrical impulse (a.k.a. action potential)

Front 5

bradycardia

Back 5

slow heartbeat (<60 bpm)

Front 6

bundle branches

Back 6

electrical conduction path in heart

leads from AV bundle down through the wall between the ventricles

Front 7

calcium ion channel

Back 7

pathway in a plasma membrane through which calcium ions enter and leave

Front 8

cardioversion / defibrillation

Back 8

conversion of fibrillation to a normal heart rhythm

Front 9

catheter ablation

Back 9

destruction of abnormal myocardial cells

restores normal cardiac rhythm

Front 10

depolarization

Back 10

plasma membrane charge is changed - inside is made less negative

loss of membrane potential

Front 11

dysrhythmia

Back 11

abnormal cardiac rhythm

Front 12

ectopic foci / pacemakers

Back 12

cardiac tissue (outside the normal cardiac conduction pathway) that generates action potentials

Front 13

electrocardiogram (ECG)

Back 13

device that records the electrical activity of the heart

Front 14

fibrillation

Back 14

dysrhythmia

complete disorganization of heart rhythm

Front 15

flutter

Back 15

dysrhythmia - contractions become extremely rapid & uncoordinated

ventricular flutter requires immediate treatment

Front 16

implantable cardioverter defibrillator

Back 16

device placed in the patient to detect and correct dysrhythmias as they occur

able to store information for future evaluation

Front 17

polarized

Back 17

inside of a cell is more negatively charged than the outside

Front 18

potassium ion channel

Back 18

pathway in a plasma membrane through which potassium ions enter and leave

Front 19

Purkinje fibers

Back 19

electrical conduction path going from the bundle branches to all portions of the ventricles

Front 20

refractory period

Back 20

period during which the myocardial cells rest and are not able to contract

Front 21

sinoatrial (SA) node

Back 21

pacemaker of the heart - located in the wall of the right atrium

Front 22

sinus rhythm

Back 22

number of beats per minute normally generated by the SA node

normal sinus rhythm = approx. 75 bpm

Front 23

sodium ion channel

Back 23

path in plasma membrane through which sodium ions enter and leave

Front 24

supraventricular

Back 24

located above the ventricles -or- in the atria

can refer to dysrhythmias

Front 25

tachycardia

Back 25

fast heartbeat (>100 bpm)

Front 26

antidysrhythmic categories

Back 26

* Class I - Sodium channel blockers

* Class II - beta-adrenergic blockers

* Class III - potassium channel blockers

* Class IV - calcium channel blockers

* miscellaneous antidysrhythmic drugs

Front 27

A client with heart failure is prescribed digoxin (Lanoxin) 0.3 mg. It is available as digoxin 500 mcg/2 ml. How many ml's will the nurse administer?
a. 1 ml
b. 1.1 ml
c. 1.2 ml
d. 1.3 ml

Back 27

c. 1.2 ml

Front 28

The physician orders enalapril (Vasotec) 15 mg. It is available as 10 mg/ 5 ml. How many ml's will the nurse administer?
a. 6 ml
b. 6.5 ml
c. 7.5 ml
d. 8 ml

Back 28

c. 7.5 ml

Front 29

T.N., age 64, receives hydralazine (Apresoline) 50 mg. It is available as hydralazine 25 mg/ tablet. How many tablets are needed to administer this dose?
a. 2 tabs
b. 3 tabs
c. 4 tabs
d. 5 tabs

Back 29

a. 2 tabs

Front 30

Atrial dysrhythmias occur more commonly in men than women.

True or False

Back 30

TRUE

p231

Front 31

An action 1_____ begins when sodium ion channels located in the 2_____ membrane open and Na+ rushes into the cell producing a rapid 3_____, or loss of membrane potential. During this period, Ca++ also enters the cell through 4_____ ion channels, although the influx is 5_____ than that of sodium. It is this influx of Ca++ that is responsible for the 6_____ of cardiac muscle.

Back 31

1 potential
2 plasma
3 depolarization
4 calcium
5 slower
6 contraction

Front 32

Blocking potassium, sodium, or calcium ion channels is a pharmacological strategy used to terminate or prevent dysrhythmias.

True or False

Back 32

TRUE

p235

Front 33

During 1_____ and most of 2_____, the cell can't initiate another action 3_____. This 4_____ period allows the action potential to finish and the 5_____ cell to contract before a second action potential begins. Some antidysrhythmic agents work by causing 6_____ of the refractory period.

Back 33

1 depolarization
2 repolarization
3 potential
4 refractory
5 muscle
6 prolongation

Front 34

quinidine sulfate

Back 34

AKA: Quinidex
CLASS: sodium channel blocker (class I)
ACTION: blocks sodium ion channels in myocardial cells - reduces automaticity - slows conduction of electrical impuls through myocardium - can correct variety of atrial & ventricular dysrhythmias
A/E: nausea - vomiting - diarrhea - serious interaction can occur w/digoxin

Hint 34

sodium channel blocker

Front 35

propranolol

Back 35

AKA: Inderal
CLASS: beta-adrenergic blocker (class II)
ACTION: reduces heart rate - slows conductive velocity - lowers blood pressure - non-specific beta-blocker
A/E: hypotension - bradycardia - diminished sex drive - impotence

Hint 35

beta-adrenergic blocker

Front 36

amiodarone

Back 36

AKA: Cardarone
CLASS: potassium channel blockers (class III)
ACTION: blocks inactivated Na+ channels, K+ channels, and interferes w/myocardial cell-to-cell coupling - half-life up to 100+ days
A/E: pneumonia-like syndrome - blurred vision - rashes - nausea - vomiting - fatigue - dizziness - hypotension - increases digoxin levels - enhances action of anticoagulants

Hint 36

potassium channel blocker

Front 37

verapamil

Back 37

AKA: Calan - Isoptin - Verelan
CLASS: calcium channel blocker (class IV)
ACTION: inhibits flow of Ca++ into myocardial cells & vascular smooth muscle - slows conduction velocity & stabilizes dysrhythmias in heart - lowers BP - dilates coronary arteries
A/E: headache - constipation - hypotension - bradycardia - increases digoxin levels

Hint 37

calcium channel blocker

Front 38

After the action potential has passed and the myocardial cell is in a depolarized state, repolarization depends upon removal of _____ from the cell.

Back 38

sodium

Front 39

A blockade of sodium channels in myocardial cells will:
a. slow the spread of impulse conduction
b. increase the spread of impulse conduction
c. stop the spread of impulse conduction
d. worsen a dysrhythmia

Back 39

a. slow the spread of impulse conduction

Front 40

Lidocaine is given 1_____ to terminate 2____ dysrhythmias.

Back 40

1 intravenously
2 ventricular

Front 41

The way beta-adrenergic blockers prevent dysrhythmias is to:
a. speed up impulse conduction across the myocardium
b. slow impulse conduction across the myocardium
c. block calcium channels
d. block sodium channels

Back 41

b. slow impulse conduction across the myocardium