Lecture 02_Spring

Question 1

What is the half-life of Adenosine?

Answer 1

Half-time is 0.6-1.5 seconds

Should follow administration with a flush syringe to get it in fast

Question 2

______ is one of the few vasodilators that also lowers heart rate.

Answer 2

Verapamil

AV node depression bradycardia
Coronary and peripheral artery vasodilation (Tx for angina pectoris and HTN)

Question 3

Which of the following are myocardial effects of Ca channel blockers?

A. Decreased myocardial contractility
B. Decreased heart rate
C. Decreased SA node activity and/or AV node conduction
D. Vascular smooth muscle relaxation
E. All of the above

Answer 3

E. All of the above

Question 4

The following are the 4 classes of anti-arrhythmic drugs. Indicate which class each describes (Class I, II, III, or IV)

Ca channel blockers
Beta blockers
K channel blockers
Na channel blockers

Answer 4

Class I - Na channel blockers
Class II - Beta blockers
Class III - K channel blockers
Class IV - Ca channel blockers

Question 5

Which drug is used to identify / treat AV nodal supraventricular tachycardias (re-entrant tachycardias, atrial tachycardia) and how?

Answer 5

Adenosine

Stimulates supraventricular potassium channels hyperpolarization, decreased depolarization

(These channels are not present in ventricular myocytes)

Question 6

Which of the following drugs is a positive inotrope but negative chronotrope?

A. Verapamil
B. Diltiazam
C. Digoxin
D. Nicardipine

Answer 6

C. Digoxin

Negative Chronotropin Agent
Slows conduction through AV node -> reduce ventricular rate

Increases parasympathetic nervous system activity -> decreases SA node activity

Positive inotropic agent
Inhibits Na-K-ATP transport system: Increased intracellular Na -> increased intracellular Ca > increased contractility

Question 7

What effect do Ca channel blockers have on the heart?

Answer 7

Decrease myocardial depolarization rate and conduction velocity

Question 8

Which drug has anti-arrhythmic properties of all 4 classes? (Class I, II, III, and IV)

Answer 8

Amiodarone

Question 9

What effect do K channel blockers have on the heart?

Answer 9

Prolong cardiac depolarization and action potential duration. They also decrease proportion of the cardiac cycle when myocardium is excitable

Question 10

sotalo and bretylium belong to what drug class?

Answer 10

Class III - K channel blocker

Question 11

What is the initial IV dose for Amiodarone?

Answer 11

300 mg IV or 5mg/kg

Question 12

What is the initial dose of Adenosine? What about subsequent doses?

Answer 12

Starting dose = 6 mg IV, then 12 mg IV, then 12 mg

Question 13

What is the drug of choice for supraventricular tachydysrhythmias and how does it work?

Answer 13

Diltiazem (Cardizem) - Blocks Ca channels of AV node

Question 14

Which drug causes transient heart block (AV Node) leading to a brief ventricular asystole?

Answer 14

Adenosine

Question 15

Which Ca Channel blocker crosses blood-brain barrier and is used for prevention of cerebral vasospasm?

Answer 15

Nimodipine