Drugs For Cardiac Arrhythmias - Dr. Konorev Flashcards
antiarrhymia drugs : class 1 class 2 class 3 class 4
- Na channel Blockers class, ABC
- Beta blockers
- K+ Channel Blockers
- Cardioactive CCB
class 1A drugs 3
= Na channel Blockers class
- Quinidine
- Procainamide
- Disopyramide
class 1B drugs 2
= Na channel Blockers class
- Lidocane
- Mexiletine
class 1C drugs 2
= Na channel Blockers class
- Flecainide
- Propafenone
Class 2 drugs 2
= BB
- Esmolol
- Propanolol
Class 3 Drugs 4
= K+ Channel Blocker
- Amiodarone
- Sotalol
- Dofetilide
- Ibutilide
Class 4 drugs 2
= Cardioactive CCB
- Dilitiazem
- Verapamil
Fast AP where
- Ventricular contractile cells
- Atrial cells
- Purkinje fibers
Slow AP where
- SA node
2. AV node
Fast AP phases
0 : fast Na+ open , Na+ enters cell
1 : K+ exit cell, Na+fast close (some repolarization)
2. plateau phase, K+ exit, Ca+ enter slow voltageC
3. Ca+2 slow close, K+ exits faster
(fast repolarization)
4. resting membrane potential (Na/K+, and Na/Ca)
phase 4 has what channels pacemaker (slow AP)
- If (funny current) : Na+ channel, K+ channels
- slow Ca+
= slanted up line until threshold
phase 0 has what channels pacemaker (slow AP)
- slow L type (long lasting Ca+ influx)
phase 3 has what channels pacemaker (slow AP)
- K+ exits, repolarization
2. Ca+ close
no class antiarrhythmic drug
adenosine
refractory period
Na+ inactive stage
class 1 drug Na blockers MOA
Block Na = prolong phase 0
Block K+ = prolong AP duration
class 1 drug Na blockers EKG changes
- prolong QRS (NA+ block)
- prolong QT interval (K+
block)
Procainamide clinical use
- not as much due to lupus related side effects
2. sustained V Tachy, or MI arrhythmia
Procainamide adverse effects
- prolong QT
- torsade de pointes **
- syncope
- Lupus erythemaatosus syndrome ** + arthritis, pleuritis, pulm D, fever, hep
- hypotension
Quinidine is from what and clinical use
Cinchona bark
- rare
- may enhance AV conductance
Quinidine adverse effects
QT interval prolongation
torsade de pointes **
GI issues
CNS probs
Disopyramide MOA beside Na block
clinical use
anti-muscarinic effect
= recurrent V arrythmias
Disopyramide adverse effects
- QT prolongation **
- torsades de pointes **
- iontrophic effect can cause HF
- atropine -like sx : tachy, dry, blurred vision, C, urinary retention
class 1B drugs do what
block NA by binding to inactivated NA (long QRS)
DONT block K+ (QT and AP length normal)
Lidocaine administered how and clinical use
IV only
= ventricular tachy during Acute MI
= also used for a local anesthetic
Lidocaine adverse effects
least toxic
- can cause hypotension , tremor, slurred speech, paresthesias
Mexiletine administration and clinical use
oral
= V arrhythmia
= chronic pain relief (diabetic neuropathy + nerve injury)
Mexiletine adverse effects
tremor
blurred vision
lethargy
Class 1C drugs do what
block NA (prolong QRS) Block K+ (only same QT and AP length)
Flecainide clinical use
= supraventricular arrhythmia
= refractory severe V arrhythmia
Flecainide adverse reactions
make arrhythmia worse
Propafenone clinical use
= supraventricular arrhythmia
Propafenone adverse effect
worse arrhythmia
Class 2 drugs effect what channels and usually acts on what cells
- increase cAMP
- If (funny current) to open slower
- lower Ca channel
= pacemaker cells (lower slope of phase 4
BB have what effect on EKG
- SA = decrease HR (longer RR interval)
2. AV = decrease AV conductance (longer PR interval)
Propanolol clinical use
cardiac arrhythmia from : = atrial flutter, atrial fib = stress and thyroid storm = MI = Paroxysmal supraventricular arrhythmia
Esmolol clinical use and administration
short lived B1 blocker, continuous IV
= supraV
= thyrotoxicosis
Class 3 drugs do what
block K+ (regulate AP length = regulating refractory period)
BB and EKG
prolong QT segment
= lower slope of phase 3
Amiodarone clinical use
most used
= recurrent V tachy
= atrial fib
(slows HR and AV conduction)
Amiodarone adverse effects
= fatal pulmonary fibrosis
= hypo or hyperthyroidism
= torsades de pointes (since it prolongs QT and AP) ONLY RARE with this drug**
Sotalol does what and clinical use
= nonselective B blocker and K+ blocker
= severe V arrhythmia
= atrial fib to keep sinus rhythm
Sotalol adverse effects
- torsades
2. depress cardial function
Doferilide and Ibutilide clinical use
restore sinus rhythm
esp after Atrial fib
Doferilide maintains it
Class 4 drugs L CA+ channels
also has inactive phase
= Ca+ usually closes the gate (when its high ICM)
Class 4 drugs L CA+ channels does what to graph and what cells
- phase 0 decrease slope
2. increase threshold potential in SA and AV node
Verapamil, Diltiazem clinical use
= termination + prevention of paroxysmal supraventricular tachycardia
= V rate during A fib and a flutter controlled
adenosine does what MOA
- activates a Gi
- increase K+ exit and inhibit Ca+, inhibit If
- hyperrepolarization, lowering AP
adenosine clinical use
sinus rhythm in paroxysmal supraventricular arrhythmia
by IV
Adenosine cells it acts on and graph
pacemaker cells (AV and SA) = inhibits AV conduction and longer AV refractory period
