Class 4&Misc. Anti-Arrhythmic Drugs Flashcards
What are the Class 4 drugs?
Verapamil
Diltiazem
MOA for Class 4 drugs?
Block L-type Calcium channels
What effects will Class 4 drugs have on the slope of phase 0 and threshold potential of the L-type calcium channels?
- Decrease slope of phase 0
- Increase threshold potential of L-type calcium channels
Overall effects of Class 4 drugs on the nodal cells?
- Decrease HR at SA node
- Prolong conduction and refractory time in AV node
Verapamil and Diltiazem are used to terminate, prevent and control?
Ventricular rate
What adverse effects can Verapamil and Diltiazem result in?
Constipation
AV block and SA node arrest
What is the Miscellaneous drug?
Adenosine
MOA for Adenosine?
(+) A1 adenosine receptor coupled to Gi
=> enhances K+ current and (-) calcium and funny channels
Overall MOA for Adenosine?
Hyperpolarization and suppression of action potentials
What does Adenosine relieve rapidly?
Paroxysmal Supraventricular Tachycardia
What does Adenosine relieve rapidly?
Paroxysmal Supraventricular Tachycardia
What are some adverse effects seen with Adenosine use?
Shortness of breath and bronchoconstriction
Chest burning
MOA for Adenosine?
- (+) A1 adenosine receptors coupled to Gi
- Enhances K+ current
- (-) Calcium and funny currents
= Marked hyperpolarization and suppression of APs
Results of the CAST trial?
Flecainide and other class 1C drugs caused increased mortality and proarrhythmias
Results of CAST trial?
Flecainide and other class 1C drugs caused increased mortality and proarrhythmias
Certain Anti-arrhythmic drugs can trigger fatal arrhythmias. Which classes of drugs can cause Torasade de pointes?
(slow conduction)
= Class 1A and 3
Certain Anti-arrhythmic drugs can trigger fatal arrhythmias. Which drug classes can cause ventricular tachycardias?
(slow conduction)
= Class 1A and 1C
Atrial Fibrillation is due to formation of?
Re-entry circuits
Which drug classes can treat Afib by terminating re-entry circuits?
Class 1C and 3
Which drug classes can treat Afib by terminating re-entry circuits?
Class 1C and 3
Cardioversion converts back to?
Sinus rhythm
In patients with structural heart disease, which 3 drugs can be considered for Afib/
Sotalol
Amiodarone
Dofetilide
To control the rate with Afib, what drugs can be considered (generally)?
CCB, Beta blockers and amiodarone
What is the most common type of Paroxysmal Supraventricular Tachycardia?
AVNRT
- Atrioventricular Nodal Re-entrant Tachycardia
What is Paroxysmal Supraventricular Tachycardia subtype AVNRT?
Re-entry of impulses into AV node
What can be used to Terminate AVNRT?
Adenosine, CCB, Beta blocker
What can be used to prevent AVNRT?
CCB or beta blockers
Torsade de pointes
Long QT interval
Torsade de pointes is prolonged _____
Repolarization (QT interval)
What classes of drugs often cause Torsade de pointes?
Class 1A and 3
What medications for covid can cause Torsade de pointes?
Chloroquine and Azithromycin combo
Besides meds, what can cause Torsade de pointes?
Electrolytes changes and decreased HR
What are 3 treatments for Torsade de pointes?
- Treat electrolyte changes
- Magnesium sulfate
- Pacemaker/ Isoproterenol
What are 3 treatments for Torsade de pointes?
- Correct electrolytes
- Magnesium sulfate
- Pacemaker/Isoproterenol
