TBL Anti-arrhythmic Drugs

Question 1

Supraventricular tachycardia (SVT)

Answer 1

• ventricular rate is driven by abnormal pacemakers above the ventricle (e.g., atria or AV node)
• examples: atrial fibrillation, atrial flutter, AVNRT
• QRS interval is normal (“narrow”)
• treated with either “rhythm control” or “rate control” approaches

Question 2

Ventricular tachycardia (VT)

Answer 2

• ventricular rate is driven by abnormal pacemakers within the ventricle
• QRS interval is abnormal (“wide”)

Question 3

Quinidine

Answer 3

Class 1A, Na Ch. Blocker AND K Ch. Blocker

MOA: decrease CV = decrease reentry circuit

USE: SVTs (“rhythm control”), VT

“HEY QTT = 2 Ts both svt and vt”

AE: risk of TdP, N/V/D, hypokalemia, hypotension, increased AVC, HA/tinnitus/deaf, thrombocytopenia

DDI: CYP2D6 inhibitors

Question 4

Procainamide

Answer 4

Class 1A, Na Ch. Blocker AND K Ch. Blocker

MOA: decrease CV = decrease reentry circuit

“HEY PRO, U SMOKING VTHL”

USE: VT

AE: risk of TdP, hypotension, lupus

Question 5

Lidocaine

Answer 5

Class 1B, Na Ch. Blocker

MOA: decrease CV = decrease reentry circuit

*Relatively selective for ischemic/rapidly firing cells - Not effective in atrial cells

“TAKE THE L, VVCC”

USE: VT, V fib

AE: CNS tox (drowsy, agitation, tremors, seizures), CV collapse/cardiac arrest

Question 6

Flecainide

Answer 6

Class 1C, Na Ch. Blocker

MOA: decrease CV = decrease reentry circuit

USE: SVTs, VT

“F U TT”

AE: increase mortality in MI/PVC pts

AVOID in pts w HF or MI or structural HD

Question 7

Metoprolol (β1 selective)
Propranolol (non-selective)

Answer 7

Class 2, beta blockers

MOA: blocks β1 on AVN = decrease CV = decrease APs reaching ventricle from an SVT and decreases DADs

USE: SVTs (“rate control”), decrease ischemia-related arrhythmias after MI

“I LOL SVT”

AEs: same as other lectures

Exaggerated effects if combined with non-DHP CCBs

Question 8

Amiodarone

Answer 8

Class 3, K ch. blockers

MOA: blocks K+ channels = increase refractory period = disrupts reentry

USE: SVTs, VT, V fib

“AM I THE BEST, VVV”

AEs:
-Hypotension
-Pulmonary fibrosis
-Corneal microdeposits
-Blue/gray skin discoloration
-Hepatotoxicity
-Neurotoxicity Hypo/Hyperthyroidism
-Photosensitivity

Question 9

Verapamil, Diltiazem

Answer 9

Class IV, CCB (non-DHP CCBs)

MOA: blocks LTCCs on AV node = decrease CV = decrease APs reaching ventricle from an SVT

USE: SVTs

AEs: Bradycardia/AV block
Hypotension, HF, constipation

Question 10

Adenosine

Answer 10

Class V

MOA: stimulates A1 receptors on AV node = decrease CV = disrupts reentry circuit

“AAY R U DTF”

US: AVNRT ( aka: PSVT)

AEs: transient asystole, dyspnea, flushing, anxiety

*Caffeine/methylxanthine drugs block adenosine = require higher dose
*Very rapid half-life so only used as I.V. bolus

Question 11

Digoxin

Answer 11

Class V

MOA: blocks Na+-K+ ATPase
-increase para, decrease symp

USE: A fib w/ HF

AEs: Cardiac arrhythmias, GI (nausea), visual distrubances, CNS (disorientation)

Question 12

Atropine

Answer 12

Muscarinic antagonist

Used to treat bradycardia/AV block

Question 13

NaCB - Classification: Double Quarter Pounder

Answer 13

Class 1A

Disopyramide, Quinidine, Procainamide

Question 14

NaCB - Classification: Lettuce and Mayo

Answer 14

Class 1B

Lidocaine, Mexiletine

Question 15

NaCB - Classification: Fries Please

Answer 15

Class 1C

Flecainide, Propafenone