30 - arrhythmic drugs

Question 1

movement or procedure with uniform or patterned

recurrence of a beat, accent, or the like

Answer 1

rhythm

Question 2

Heartbeat is irregular, too fast, or too slow

Answer 2

cardiac arrhythmia

in atrial fibrillation, the tracing shows tiny, irregular “fibrillation” waves btw heart beats

the rhythm is irregular and erratic

Question 3

Contraction of _
ventricle sends O2
depleted (and CO2
rich) blood to the lungs.

Contraction of the _
ventricle sends O2
rich blood to the other tissues.

Electrical signals
coordinate cardiac
muscle contraction

Answer 3

right ventricle - O2 depleted and CO2 rich

left ventricle - O2 rich to other tissues

Question 4

the sum total of action potentials traveling

through the heart creates the _

Answer 4

EKG

Question 5

Diagnostic components of the EKG

_ reflects
depolarization of SA
node

Answer 5

P wave

Question 6

Diagnostic components of the EKG

_describes the time it takes for the
impulse to travel from sinus node through AV node

Answer 6

PR interval

Question 7

Diagnostic components of the EKG

_ reflects
depolarization of right
and left ventricles
(lots of muscle mass,
big signal).

Answer 7

QRS complex

Question 8

Diagnostic components of the EKG

_ segment Ventricles depolarized

Answer 8

ST segment.

J point - ventricles depolarized - J point is important because it is the start of the ST segment. The J point must be assessed for:
absolute position: it can be elevated or depressed
shape: it can be notched or slurred

Question 9

Diagnostic components of the EKG
Repolarization
of ventricles

Answer 9

T wave.

Question 10

Diagnostic components of the EKG

repolarization of
interventricular
septum.

Answer 10

U wave

Question 11

Four main types of arrhythmias
Extra beats
Supraventricular tachycardias
Ventricular arrhythmias
bradyarrhythmias

Answer 11

extra beats - Premature atrial contractions, Premature ventricular contractions

supraventricular tachycardas - Atrial fibrillation
Atrial flutter
Paroxysmal supraventricular tachycardia

ventricular - Ventricular fibrillation
Ventricular tachycardia

bradyarrhythmias - less than 60bpm

Question 12

Classification of arrhythmias by _
Atrial
Junctional
Ventricular
AV Heart blocks (atrioventricular node)

Answer 12

site of origin

Question 13

_ arrhythmia

Conduction between the atria and ventricles is blocked or slowed

PR interval lengthened beyond 0.2 seconds

Answer 13

primary AV block

200msec or longer

Question 14

_ arrhythmia

Conduction between the atria and ventricles is blocked or slowed

Disturbance, Delay, Interruption of atrial
impulse conduction through the AV node to the ventricles

PR interval - 0.12-0.2sec

Answer 14

secondary AV block

2,3,or 4 P wave before each QRS

PR interval - 0.12-0.2sec - little delay

QRS <0.12s

Question 15

_ arrhythmia

Conduction between the atria and ventricles is blocked or slowed

aka complete heart block. Impulse generated
in SA node does not propagate to the ventricles.

Answer 15

tertiary AV block

none of the pwaves conduct to ventricles (P-P and QRS-QRS are independent)

Question 16

cardiac arrhythmias result from disorders of impulse _ or impulse_ or both

Answer 16

disorders of impulse formation or
impulse conduction or both

causes of arrhythmias
~cardiac ischemia
~excessive discharger or sensitivity to autonomic transmitters
~exposure to toxic substances
~unknown ?

Question 17

_ puts little delay on the wave on Ap’s thru heart

Answer 17

AV node

atrial first then ventricles

Question 18

sum total of AP’s traveling thru heart - but at different times

Answer 18

ECG/EKG

Question 19

if patient has an arrhythmia

Can always be a secondary problem of _ - when blood isn’t moving smoothly thru system

Answer 19

clotting

Question 20

4 classes of drugs for arrhythmic drugs

Class 1 - block Na channels

Class 2 - beta anatagonists

Class 3 - prolong AP and refractory period

Class 4 - Ca channal antagonist

which phase of heart

Answer 20

1 - phase 0, depolarization Na coming in

2 - phase 4 - resting potential K+

3 - between phase 1 and 3 - working on K channels

4 - phase 2 - blocking Ca

Question 21

phases of cardiac AP

0-4

Answer 21

0- Na coming in steep rise
1 - K+ and Cl- out 
2 - Ca++ in K+ out
3 - K out
4- resting potential

Question 22

Class 1 antiarrhythmic drugs block _

Answer 22

block Na channel

Drugs with intermediate lengths bind to Na channels - not shutting down but tweaking enough to cause little change
When injecting Lidocaine - we block entire Na channel and prevent AP all

We are tweaking the depolarization (Na channel) and changing AP stop

Question 23

Class 1 Na channel blockers

Lengthen duration of action potential.

Bind more selectively to the open state of the channel.

Dissociate from channel with intermediate kinetics.

Answer 23

class 1 A

increase QRS and QT

Question 24

Class 1 Na channel blockers

Shorten duration of action potential.

Bind primarily to inactivated state of
the channel.

Dissociate from the channel with rapid kinetics.

Answer 24

class I B

decrease QT

Question 25

Class 1 Na channel blockers Minimal effect on duration of action potential. Bind more selectively to the open state of the channel. Dissociate from channel with slow kinetics.

Answer 25

class 1 C increase QRS duration most

Question 26

which ABC of class 1 antiarrhythmic drugs Procainamide. Effective against atrial and ventricular arrhythmias. Frequent dosing (t1/2 = 3 hrs) limits its utility. Can produce lupus like symptoms.

Answer 26

class 1 A Lengthen duration of action potential. Bind more selectively to the open state of the channel. Dissociate from channel with intermediate kinetics

Question 27

which ABC of class 1 antiarrhythmic drugs Lidocaine. One of the less toxic antiarrhythmic drugs. Used in conjunction with arrhythmias associated with myocardial infarctions. Very short t1/2. Administered by infusion

Answer 27

class 1 B Shorten duration of action potential. Bind primarily to inactivated state of the channel. Dissociate from the channel with rapid kinetics

Question 28

which ABC of class 1 antiarrhythmic drugs Flecainide and Propafenone. Used to treat supraventricular arrhythmias

Answer 28

class I C Minimal effect on duration of action potential. Bind more selectively to the open state of the channel. Dissociate from channel with slow kinetics.

Question 29

class _(1-4) of antiarrhythmic drugs diminish phase 4 depolarization, thus depressing automaticity, prolonging AV conduction and decreasing HR and contractility

Answer 29

class 2 beta-adrenergic antagonists beta 2 atagonist if heart is beating too fast

Question 30

how do class 2 betablockers work they can diminish both _ and _ currents

Answer 30

diminsh both Na and Ca phase 4 of the cardiac AP

Question 31

which receptor | - increase force of heart contraction, increase rate of contraction, excessive stimulation leads to arrhythmias

Answer 31

beta 1

Question 32

what kind of beta adrenergic drug do we use if that patients heart is beating too fast

Answer 32

beta 2 antagonist

Question 33

class _ antiarrhythmic drugs block potassium K+ channels and thus prolonging AP delayed repolarization

Answer 33

class 3 K+ channel blockers

Question 34

in contrast to the sodium-channel blockers, _ and _ drugs are increasing in use

Answer 34

class 2 - Beta blockers and class 3 K channel blockers

Question 35

Class _ antiarrhythmic drugs block Ca++ channels decrease inward Ca current, decreasing rate of phase 4 spontaneou depolarization slow conduction in tissues dependent on Ca current (AVnode) MAJOR EFFECTS ON VASCULAR SM AND HEART THOUGH

Answer 35

class IV blocking Ca channels major systemic effects though slow conductiong and increase refractory period verapamil