Antidysrhythmic Drugs Flashcards
What is the difference between Dysrhythmia and Arrhythmia?
Dysrhythmia - any deviation from normal rate/rhythm
Arrhythmia - no rhythm
Can be used interchangeably
What is asystole?
No heartbeat
What’s the difference between Tachydysrhythmias and Bradydysrhythmias?
Tachy is much more common. HR is increased and can be caused by drugs and other treatments
Brady is a slower HR, due to electrical pacing, can be impacted by drug Atropine
What are 5 causes of dysrhythmias?
ischemic heart disease myocardial infarction cardiomyopathy myocarditis electrolyte imbalances
What purpose does AP generation have?
AP leads to contraction in myocardial muscles
What ion does the SA and AV node cells need to depolarize?
Ca2+
What ion does Ventricula/Atrial muscle cells need to depolarize?
Na+
What are 4 symptoms of dysrhythmias?
Palpitations
Dizziness
Fainting - when heart beats fast, there’s not enough time for it to fill. This reduces CO and blood won’t travel to head
Dyspnea
Where does Supraventricular tachycardia originates, and what can it cause?
Origin of the dysrhythmia is in the atria
Beats 120-250
Can cause atrial flutter and atrial fibrillation.
The heart is beating very fast in the atrial flutter, and it is very unorganized and not even beating in fibrillation
What can Ventricular Tachycardia cause?
Ventricular fibrillation
- Quivering ventricles. Blood is not effectively pumped to the rest of the body
More dangerous than atrial fibrillation
When should you use a A-V block?
With Supraventricular dysrhythmias
What are the classes of the Vaughan Williams Classification?
Class 1: Na channel blockers - Class 2: B blockers Class 3: K channel blockers Class 4: Calcium channel blockers Other: adenosine, digoxin
What is an example of a Class 1a blocker? When should you use it?
Quinidine
Used for acute onset of atrial fibrillation
- Wolff-Parkinson-White syndrome (usually tachy but can be slow with atrial fib/flutter)
- Slows atrial and ventricular rates
What is an example of a Class 1b blocker? What is the only dysrhythmia it’s used for?
Lidocaine
Used for ventricular dysrhythmias only
What is an example of a Class 2- B-adrenoceptor antagonist? What’s another name for this class?
Metoprolol
Reduces or blocks sympathetic nervous system (AV Block)
What is an example of a Class 3 K blocker? What is used for and what are the long term side effects?
Amiodarone
Prolongs repolarization, extended refractory period of cells.
75% have serious adverse effects (lung fibrosis, thyroid)
Used for ventricular tachycardia or fibrillation, atrial fibrillation or flutter
- Resistant to other drugs
What are 2 examples of a Class 4 calcium blocker? Which node does it act on? When should you use it?
Diltiazem, Verapamil
Mostly used for atrial problems, forms an AV block
Use for periodic attacks and not for ventricular dysrhythmias
What are 2 unclassified Antidysrhythmics?
Digoxin, Adenosine
- both decrease AV conduction and SA automaticity
What is the half-life of Adenosine? How is it administered and how does it function?
Slows conduction through the AV node
- AV block
Half life 20-30 seconds
Only administered as fast push IV
May cause asystole for a few seconds
What is the major adverse effect of Antidysrhythmic drugs?
They can cause dysrhythmias!
What are 5 symptoms the patient should be aware of?
SOB Edema Dizziness Syncope Drug toxicity
When should you notify a physician with patients who are taking B-blockers or digoxin?
When the pulse (taken for 60 seconds radial) is less than 60 bpm
