Anti arrhythmic agents chapter 45

Question 1

Describe the automaticity, excitability , conductivity, contractility of the cardiac muscle s

Answer 1

-Automaticity – cells can spontaneously initiate impulse or action potential – pacemaker cells
-Excitability – ion shift – ability to respond to impulse and generate action potential
-Conductivity – able to transmit impulse
-Contractility – how well cell contracts after receiving a stimulus
** Injured/ scarred cells lose excitability **

Question 2

What is the normal functioning conductivity

Answer 2

Impulse starts in SA node 
Transmitted to AV node 
Down bundle of His 
Purkinje fibers

Question 3

What is arrhythmias? and what can cause them

Answer 3

Arrhythmias involve changes of rate and rhythm due to automaticity or conduction abnormalities

Causes:
Electrolyte imbalance – Ca, K, Na, Mg
Hypoxia
Structural damage that alters conduction pathway
Acidosis/waste accumulation – renal failure
Other cardiac drugs – pro-arrhythmic

Question 4

What is the goal of anti-arrhythmic drugs?

Answer 4

Alter heart’s electrical conduction system

Mechanism of action is to reduce automaticity, slow conduction and prolong refractory period( cant respond to any new stimuli)

Goal is to prevent arrhythmias, relieve symptoms, and prolong life

Question 5

What are indications of anti-arrhythmic drugs?

Answer 5

atrial fibrillation and atrial flutter
decrease ventricular rate and irregularity
may also be used for HTN control

Question 6

What are different classes of anti-arrhythmic drugs?

Answer 6

Class I – Sodium channel blockers
**lidocaine (Xylocaine)
Class II – Beta blockers
**metoprolol (Lopressor)
Class III – Potassium channel blockers
**amiodarone (Cordarone)
Class IV – Calcium channel blockers
**diltiazam (Cardizem)

Question 7

What are different classes of sodium channel blockers?

Answer 7

anti-arrhythmic
Class 1a- procainamide (Pronestyl)
Class 1b- **lidocaine (Xylocaine)
Class 1c- flecainide (Tambocor)

Question 8

What is the therapeutic action of lidocaine (Xylocaine)?

Answer 8

anti-arrhythmic, Class 1b

-Block the movement of sodium into cells of cardiac conduction system
-Slows conduction, prolongs refractory period, decreases automaticity, stabilizes cell membrane

Class Ib drugs depress phase 0 somewhat and shorten the duration of the action potential.

Question 9

What are the indications of lidocaine (Xylocaine)?

Answer 9

anti-arrhythmic, Class 1b

used for ventricular arrhythmias

Atrial fibrillation, premature atrial & ventricular contractions (PAC’s & PVC’s), V tach

Question 10

What are the pharmokinetics of lidocaine (Xylocaine)?

Answer 10

anti-arrhythmic, Class 1b
Given IV due to extensive first pass effect, dose reduce with renal dz and rapid onset
Decreases myocardial irritability

Question 11

What are the adverse effects of lidocaine (Xylocaine)?

Answer 11

anti-arrhythmic, Class 1b
CNS effects – tremors, seizures,dizziness,fatigue
GI effects – n/v, change in taste
CV effects – pro-arrhythmic effects, hypotension, vasodilation, potential for cardiac arrest

Question 12

What are contras of lidocaine (Xylocaine)?

Answer 12

anti-arrhythmic, Class 1b

Heart block, hypotension, shock
-allergy

Question 13

What are drug to drug interactions of lidocaine (Xylocaine)?

Answer 13

anti-arrhythmic, Class 1b
Potentiates oral anti-coagulants( increased risk for bleeding )

Question 14

What is class ll anti-arrythmic?

Answer 14

Beta blockers

Question 15

What is metoprolol (Lopressor)?

Answer 15

Beta blocker class ll

Question 16

What are therapeutic actions of metoprolol (Lopressor)?

Answer 16

Beta blocker class ll
Beta blockers inhibit SNS stimulation
decreases rate and contraction
decreases BP, decreases O2 demand

Question 17

What are indications of metoprolol (Lopressor)?

Answer 17

Beta blocker class ll
Rate control, HTN, acute MI, angina prevention, a-fib, a-flutter

Question 18

What are adverse effects of metoprolol (Lopressor)?

Answer 18

Beta blocker classll
r/t blocking SNS
-Constricted pupils
-Stimulate salvation
-slow hr
-vasodilation
-constrict airways
-stimulate stomach/intestines activities
-contract bladder

Barely proarrythmic so no

Question 19

What are contras of metoprolol (Lopressor)?

Answer 19

Beta blocker class ll
Bradycardia, heart block, asthma, copd andy respiratory distress

Question 20

What are cautions of metoprolol (Lopressor)?

Answer 20

Beta blocker class ll
Diabetes-can mask signs of hypoglycemia
Hypothyroidism
Hepatic/renal dysfunction

Question 21

What are drug to drug interactions with metoprolol (Lopressor)?

Answer 21

Beta blocker class ll
Caution with use of additional cardiac meds

Question 22

What are class lll

Answer 22

Potassium Channel Blockers

Question 23

What is amiodarone (Cordarone)?

Answer 23

Class III – Potassium Channel Blockers

Question 24

What is therapeutic action of amiodarone (Cordarone)?

Answer 24

Class III – Potassium Channel Blockers
Prolongs action potential and refractory period by blocking the cardiac potassium channels – vasodilate effect

Question 25

What is indications of amiodarone (Cordarone)?

Answer 25

Class III – Potassium Channel Blockers Used for ventricular irritability, V-tach and V-fib, atrial irritability

Question 26

What is adverse effects of amiodarone (Cordarone)?

Answer 26

Class III – Potassium Channel Blockers Arrhythmias Liver toxicity Ocular abnormalities(white halo) Pulmonary toxixicty

Question 27

What is contras of amiodarone (Cordarone)?

Answer 27

Class III – Potassium Channel Blockers None when used to treat life threatening incidents

Question 28

What is cautions of amiodarone (Cordarone)?

Answer 28

Class III – Potassium Channel Blockers Long QT renal/hepatic disease

Question 29

What are drug to drug interactions of amiodarone (Cordarone)?

Answer 29

Class III – Potassium Channel Blockers TCAs, anti-histamines increased risk of proarrhythmias if they are combined with antihistamines, phenothiazines, or tricyclic antidepressants

Question 30

What is diltiazem (Cardizem) ?

Answer 30

Class IV – Calcium Channel Blockers

Question 31

What are therapeutic actions of diltiazem (Cardizem) ?

Answer 31

Class IV – Calcium Channel Blockers Inhibit movement of calcium ions across myocardial/ arterial muscle cells which: slows cardiac impulse causes vasodilation reduction of blood pressure decrease of venous return delaying phases 1 and 2 of repolarization, which slows automaticity and conduction. Electrical activity through the SA and AV nodes is partially dependent on the calcium influx, so the medications slow AV conduction and ventricular rate

Question 32

What are indications of diltiazem (Cardizem)?

Answer 32

Class IV – Calcium Channel Blockers Used for a-fib, a-flutter, SVT HTN and treat angina (dilt specific

Question 33

What are adverse affects of diltiazem (Cardizem)?

Answer 33

Class IV – Calcium Channel Blockers CNS  weakness, dizziness, fatigue GI upset, N/V CV  hypotension, arrhythmias

Question 34

What are contras of diltiazem (Cardizem)?

Answer 34

Class IV – Calcium Channel Blockers Heart block could be exacerbated pregnancy, grapefruit juice can potentiate

Question 35

What are cautions of diltiazem (Cardizem)?

Answer 35

renal or hepatic dysfunction Use with other cardiac meds

Question 36

What are other drugs for arrhymias?

Answer 36

**adenosine (Adenocard) **digoxin (Lanoxin)

Question 37

Describe **adenosine (Adenocard)

Answer 37

used for SVT  slows conduction through AV node short duration of action (10-15 seconds)

Question 38

Describe **digoxin (Lanoxin)

Answer 38

Slows conduction and heart rate Good for atrial arrhythmias

Question 39

What to asses with anti-arrhythmic agents

Answer 39

Allergies VS, Neuro status Physical assessment Close attention to cardiac status Past medical history Labs; Baseline ECG

Question 40

What are nursing diagnosis with anti-arrhythmic agents?

Answer 40

Decreased cardiac output r/t cardiac effects of medication Risk for injury r/t adverse drug effects Decreased cardiac output r/t cardiac effects of medication Risk for injury r/t adverse drug effects

Question 41

What is implementation with anti arrhythmic agents

Answer 41

Monitor for med-induced arrhythmias Continuous cardiac monitoring Assess for CNS effects Safety measures/ Fall prevention Administration ALWAYS assess VS before administering Educate patient on self-management

Question 42

Whats evaluation for ant-arrhythmic agents?

Answer 42

Monitor pt response (stabilization of cardiac rhythm)