Anti-Arrhythmics Flashcards
What do IA block
Na channels Ventricular and Supraventricular
What do IB block
Na channel Ventricular only
What do IC block
Na channels Ventricular and Supraventricular
What do II block
Beta
What do III block
K channel Ventricular and Supraventricular
What do IV (4) block
Ca channel Supraventricular only
What are the IA drugs
Quinidine
Procainamide
Disopyramide
What are the IB drugs
Lidocaine
Mexiletine
Tocainide
What are the IC drugs
Flecainide
Propafenone
What are the II drugs
Metoprolol
Propranolol
Esmolol
What are the III drugs
Amiodarone
Sotalol
Dofetilide
What are the IV (4) drugs
Verapamil
Diltiazem
Draw the IC block
Draw the II block
Draw the III block
Draw the IV block
Draw the IA block
Draw the IB block
How do IA act
Slow phase 0 depol
Prolong phase 3
Slow conduction, Prolong AP
Increase ventricular refractory
Affect normal tissue
How do IB act
Slow phase 0
Decrease phase 4 slope
Decrease AP by shortening repol
Little effect on normal cells
How do II act
Reduce HR and contractility
Longer repol at AV
Decrease phase 4 slope
Less spont depol in pacemaker
How do III act
Prolong AP and QT and refractory
No effect on phase 0
Can induce Arrhythmias
How do IV act
Decrease phase 4 spont depol
Slow conduction SA and AV
Effects on vascular and cardiac SM
What other class can Quinidine act as
III
Can Quinidine cause Arrhythmias
Yes
What do we use instead of Quinidine
Ca channel blockers
When is Quinidine contraindicated
Complete heart block
Caution in prolongued QT, torsades de pointes, myocarditis
When do you give quinidine
Conversion and prevention of A-fib and flutter
Ventricular arrhythmias
Which IA are oral
Quinidine
Procainamide
What CYP does Quinidine inhibit
2D6
3A4
Also p-glycoprotein
Notable Quinidine AE
Thrombocytopenic purpura
Cichonism
Increase digoxin conc
What is Cinchonism
Blurred vison
Tinnitus
HA
Psychosis
When is Procainamide contraindicated
Hypersensitivity
Complete heart block
2nd degree AV block
SLE
Torsades de pointes
Caution in HF with HTN
When do you give Procainamide
Ventricular Arrythmias
Life threatening cases
How does Procainamide have class III activity
Partially acetylated to NAPA
Prolongs AP duration
Most important AE of Procainamide
Lupus-like syndrome
Stronger -ve ionotrope than quinidine and procainamide
Disopyramide
Which IAs work mainly on ventricular arrhythmias
Quinidine
Procainamide
Which IA is used for ventricular and supraventricular arrhythmias
Disopyramide
AE for Disopyramide
Cardiac failure w/o preexisting dysfunction
Severe antimuscarinic effects
What other channel does Disopyramide act on
K channels
What is Lidocaine commonly used for
Local anesthetic
Which IB has little effect on K
Lidocaine
What is the DOC for V-tach, V-fib after cardioversion in acute ischemia
Lidocaine
Which IB is IV only
Lidocaine
Which IB had severe hematological and pulm tox
Tocainide
Which IB is used for V-tach other than lidocaine
Tocainide
Which IB has AE in CNS and GI
Mexiletine
What happens with a toxic dose of Lidocaine
Convulsions
Coma
Why is Lidocaine IV only
First pass
Does Lidocaine have LV function or -negative inotropic effect
No
Which IC doesn’t affect slope of phase 0 of AP
Flecainide
Propafenone
Which IC increases threshold potential
Flecainide
What do you give in life-threatening arrhythmias
Flecainide
Propafenone
Procainamide
What do you give to maintain normal sinus rhythm in symptomatic A-fib
Propafenone
Amiodarone
Sotalol (and in flutter)
Dofetilide (and in flutter)
When do you give Flecainide
Refractory PVC or V-tach
Severe supraventricular arrhythmia
Prevent paroxysmal A-fib
Contraindication for Flecainide
Post-MI PVC
AE for Flecainide and Propafenone
Aggravate CHF
Dizziness, blurred vision, HA
N/V/D
Arrhythmia and V-tach
What do you use to reduce incidence of suddent arrhythmic deaths post-MI
Metoprolol
Propranolol
Used to control SVT and V-tach
Metoprolol
Propranolol
Give to control V-tach due to NE or digoxin tox
Metoprolol
Propranolol
Use for Acute arrhythmias in surgery/emergencies
Esmolol
Contraindications for class II
CHF
Bradycardia
Heart block
Hyperactive airway disease
Class II AE
Bradycardia
Hypotension
CNS effects
Class III that is a pure K blocker
Dofelitide
Structurally related to thyroxine
Amiodarone
Which Antiarrhythmic has class I, II, III, IV effects
Amiodarone
What is the most common antiarrhythmic
Amiodarone
What is low dose Amiodarone used for
Maintain normal sinus in A-fib
How long does it take for full clincal AE of Amiodarone to be apparent
6 weeks
Effects of Amiodarone
Decrease AV conduction and sinus node function
Block inactivated Na channels
Weak Ca blocker
Inhibit adrenergic stimulation
Anti-anginal
How common are Amiodarone AE
> 50% of people
Notable AE of Amiodarone
IPF
Blue/Gray skin discoloration (Iodine accumulation)
Thyroid dysfunction
What is Amiodarone never coadministered with
Digoxin
Theophylline
Warfarin
Quinidine
When do you never give Amiodarone
Bradycardia
SA/AV block
Severe hypotension
Resp failure
What kind of a drug is Sotalol
Non-selective Beta-blocker
Which drug is the delayed K channel rectifier
Sotalol
What do you NOT use Sotalol for
Asymptomatic arrhythmias
Class III with least AE
Sotalol
Main AE in Sotalol
Torsades de pointes (prolong QT)
Caution in renal impairment
AE for Dofetilide
HA, chest pain, Dizziness, V-tach
TORSADES DE POINTES
What are the Miscellaneous Antiarrhythmics
Digoxin
Adenosine
Mg
Atropine
What kind of Ca channel blockers are class IV antiarrhythmics
Non-Dihydropyridines
Which class IV is more selective for Myocardium
Verapamil
How do class IV act
Bind open, depolarized channels
Decrease HR, contractility, conduction velocity
When do you give class IV
SVT
A-fib and flutter
HTN, angina
Why do class IV cause transient increase in BP and CO
They are negative inotropes
What do you not give class IV with and why
Digoxin
Dofetilide
Simvastatin
Lovastatin
What does Digoxin do
Shorten refractory in atrial and ventricular myocardium
Lengthen refractory and lower conduction in AV node
When do you give Digoxin
A-fib/flutter with impaired LV function or HF
Direct action of Digoxin
AV node blocking
Activate Ach-mediated K currents in atrium
Indirect effects of Digoxin
Hyperpol
Shorten atrial AP
Increase AV refractory
Effect of Digoxin toxicity
V-tach
V-fib
Which miscellaneous antiarrhythmic is given in IV form
Adenosine
What is the DOC for abolishing acute SVT in emergency
Adenosine
Which antiarrhythmic is a P1r agonist
Adenosine
What does high dose Adenosine do
Decrease conduction velocity
Prolong refractory
Decrease AV automaticity
How does Adenosine act
Increase K conduction
Decrease Ca influx leading to hyperpol
What are the AE for Adenosine
Chest pain similar to MI
Hypotension
Bronchoconstriction in asthmatics
What is a functional Ca antagonist
Mg
What is used in bradyarrhythmia to decrease vagal tone and increase HR
Atropine
When is Mg used
Torsades de Pointes
Digitalis arrythmias (also lidocaine)
Arrhythmia prophylaxis in acute MI
When is Atropine used
Bradyarrhythmia
What is the most common clinical arrhythmia
A-fib
What drugs are involved in Rhythm control of A-fib
Class IC
Class III
IA (more AE)
What drugs are involved in Rate control of A-fib
Ca channel blockers
Beta blockers
Digoxin
When do you use IV Heparin to control thromboembolic events in A-fib
Unstable pts needing immediate cardioconversion
When do you use oral Warfarin to control thromboembolic events in A-fib
If cardioversion can be delayed 3-4 days