Arrhythmias

Question 1

Class I: sodium channel blockers

Answer 1

A: lengthens the duration of action potential
B: shortens the duration of action potential
C: minimally increases action potential

Question 2

Class II: beta blockers

Answer 2

Reduce adrenergic activity in the heart
Sotalol: considered a class II and III drug

Question 3

Class III: potassium channel blockers

Answer 3

Prolong effective refractory period and reduce speed of conduction

Amiodarone

Question 4

Class IV: calcium channel blockers

Answer 4

Block the influx of calcium, reduction in contractility (negative inotropism), decrease SA and AV node conduction
Significantly reduce afterload but little effect on preload

Verapamil, diltiazem, bepridil

Question 5

Quinidine, procainimide, disopyramide

Answer 5

Class I: sodium channel blockers

A: Lengthens the duration of action potential

Question 6

Lidocaine, phenytoin

Answer 6

Class I: sodium channel blockers

B: Shortens the duration of action potential

Question 7

Encainide, Iorcainide, flecainide

Answer 7

Class I: sodium channel blockers

C: Minimally increases action potential

Question 8

Amiodarone, bretylium

Answer 8

Agents which prolong duration of the action potential (potassium channel blockers)

Question 9

Verapamil, diltiazem, bepridil

Answer 9

Calcium channel blockers

Question 10

Quinidine

Answer 10

Class I: sodium channel blockers
A: Lengthens the duration of action potential

MOA: DECREASES SODIUM CONDUCTION
ACTION: 
DECREASES MEMBRANE RESPONSIVENESS
SLOWS IMPULSE CONDUCTION
USES: ATRIAL, NODAL, OR VENTRICULAR DYSRHYTHMIAS

Question 11

Procainimide

Answer 11

Class I: sodium channel blockers
A: Lengthens the duration of action potential

USE: VENTRICULAR DYSRHYTHMIAS
ALTERNATE IN ACLS
SIMILAR TO QUINIDINE BUT LESS GI UPSET
MAY PRODUCE LUPUS; BONE MARROW DEPRESSION

Question 12

Lidocaine

Answer 12

Class I: sodium channel blockers
B: Shortens the duration of action potential

USE: VENTRICULAR DYSRHYTHMIAS EMERGENCIES (ALSO LOCAL ANESTH)
SIMILAR TO QUINIDINE BUT DOES NOT SLOW AV CONDUCTION
KINETICS:
IV ONSET RAPID; SHORT DURATION
METABOLIZED IN LIVER
MEXILETINE “ORAL LIDOCAINE

Question 13

Flecainide

Answer 13

USE: ATRIAL OR VENTRICULAR DYSRHYTHMIAS “WHEN OTHER AGENTS FAIL” GIVEN PO
MAIN CONCERN: PROARRHYTHMIC

Class I: sodium channel blockers
C: Minimally increases action potential

Question 14

ADRs of Amiodarone

Answer 14

ADRs:

thyroid, neurological, blue skin discoloration, bradycardia, lung damage not evident until advanced

Question 15

Adenosine

Answer 15

USE: SUPRAVENTRICULAR ARRHYTHMIAS
TERMINATE PSVT

ACTION:
INHIBITS SA & AV NODE CONDUCTION
MAY STOP HEART

KINETICS:
VERY RAPID ONSET
VERY BRIEF (HALF-LIFE < 10 SEC.)
SE/ADR: FACIAL FLUSH; DYSPNEA

Question 16

CALCIUM CHANNEL BLOCKER

Answer 16

VERAPAMIL IV OR PO
DILTIAZEM IV

USE: SUPRAVENTRICULAR ARRHYTHMIAS