Chapter 25 - Dysrhythmias Flashcards
1
Q
Three different classes: 1A = quinidine, 1B = lidocaine (Xylocaine), 1C = flecainide (Tambocor)
A
Class: Sodium Channel Blockers
-MOA: Block sodium channels and slow velocity of conduction (electrical impulse going through heart)
2
Q
propranolol (Inderal)
A
Class: Beta Blockers
- MOA: blocks beta-adrenergic receptors in the heart and juxtaglomerular apparatus decreases influence of SNS on these tissues and excitability of the heart, cardiac workload and oxygen consumption. Has membrane stabilizing effect antidysrhythmic action
- -> Blocking sympathetic response by SLOWING HEART DOWN – allow ventricles to fill and squeeze well
- Use: cardiac dysrhythmias (SVT) and ventricular tachycardia, also used in patients post-MI
- AE: bronchospasm, bradycardia, hypotension, laryngospasm, CNS changes, HF, dysrhythmias, heart block, CVA, pulmonary edema, and more!
- -> Bronchospasm because blocking sympathetic (which causes bronchodilation
- -> AEs not that common – just make sure to watch HR and BP in patients!
3
Q
amiodarone (Coradarone)
A
Class: Potassium Channel Blockers
- MOA: prolong duration of the action potential, slow repolarization, prolong the refractory period in atria and ventricles; they block cardiac potassium channels
- Use: life threatening tachycardias (ventricles/atria)
- -> Not a good long term med for patients to be on
- AE: most are dose dependent: CNS effects, cardiac dysrhythmias, hypotension, HF, GI effects, thyroid dysfunction, pulmonary effects, hepatotoxicity (because extensively metabolized in liver – watch for jaundice)
- BBW: risk of developing fatal pulmonary toxicity
- -> Pulmonary fibrosis (mess w/ lining of lungs) patients do not get good air exchange or respirations
4
Q
diltizaem (Cardizem)
A
Class: Calcium Channel Blockers
- MOA: inhibit the influx of calcium through its channels, causing slower conduction through the SA and AV nodes
- Uses: SVT, atrial fibrillation/flutter
- AE: Hypotension, CNS effects, CV effects, flushing nausea, prodysrhythmic effects
- Contra: impaired hepatic or renal function, heart block, sick sinus syndrome
5
Q
adenosine (Adenocard)
A
Class: Unclassified
- MOA/Use: depresses conduction at AV node and restores normal sinus rhythm in patients with SVT (superventricular tachycardia - ineffective in other dysrhythmias) –> resets whole cardiac conduction system in heart
- Admin: GIVE RAPIDLY! (half-life is 10 seconds)
6
Q
magnesium sulfate
A
- MOA: improves imbalances in Mg, K, and CA –> used for severe tachydysrhythmias (torsades de pointes)
- -> torsades de pointes: can be a fatal arythmia; looks like a rotating tornado, due to low magnesium levels
- Hypomagnesemia increases myocardial irritability and is a risk factor for atrial and ventricular dysrhythmias
