Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
76 Cards in this Set
- Front
- Back
|
What are the general characteristics of the Class 1 Anti-Arrhythmics?
|
Agents w/ local anesthetic properties and that block Na Channels
|
|
|
Difference between the different types of Class 1 agents?
|
1A = lengthen action potential duration
1B = abbreviate action potential duration 1C = No changes in APD, but depress conduction velocity |
|
|
Examples of Class 1A?
|
Procainamide
Quinidine |
|
|
Examples of Class 1B?
|
Lidocaine
Phenytoin |
|
|
Examples of Class 1C?
|
Flecainide
|
|
|
Who are the Class II anti-arrhythimcs? examples?
|
Beta Blockers
Propanolol Metoprolol |
|
|
Procainamide's major effects?
|
1. Decrease Automaticity
2. Decrease Conduction Velocity 3. Increase Action Potential Duration and Refractory Period |
|
|
How does Procainamide decrease automaticity?
|
Decrease Phase 4 spontaneous depolarization and increases the threshold
|
|
|
How does Procainamide decrease conduction velocity?
|
It decreases the membrane responsiveness (Vmax)
|
|
|
How does Procainamide increase APD and RP?
|
It blocks K efflux
|
|
|
What are some other cardiac effects of Procainamide?
|
Altered ECG
Possibly excessive slowing of conduction |
|
|
what parts of the ECG does Procainamide alter?
|
Prolongs:
P-R QRS Q-T (via blocking of K channels) |
|
|
Adverse Effects of Procainamide?
|
Hypotension w/ large IV dose
Lupus-like syndrome Prolonged Q-T can => Torsades de Pointe |
|
|
How can Procainamide be administered?
|
IV
IM |
|
|
Half life of Procainamide
|
Short
3-4 hrs means you gotta give it frequently |
|
|
What is a unique, though not necessarily frequent result of Procainamide use?
|
Some people rapidly acetylate Procainamide creating a metabolite that increases frequency of torsades, but decreases chance of Lupus-like syndrome
|
|
|
Indications for Procainamide?
|
Atrial and Ventricular Arrhythmias (acute MI)
|
|
|
Electrophysiological effects of Quinidine?
|
Similar to Procainamide
|
|
|
Other Cardiac Effects of Quinidine
|
Prolonged Q-T, QRS, AND P-R
|
|
|
Adverse Effects of Quinidine
|
Severe Hypotension w/ IV
Diarrhea Dizziness Ringing in Ears Blurred Vision Can Trigger Torsades de Pointe |
|
|
Pharmacokinetics of Quinidine
|
Oral is preferred (T1/2 = 6-8hr)
IV is dangerous |
|
|
Indications for Quinidine?
|
(some) Atrial Fib and Flutter
|
|
|
How are Class 1A's often administered?
|
W/ a beta-blocker to keep the ventricle from going nuts
|
|
|
Indications for Lidocaine?
|
Prominent use w/ emergency Rx of Ventricular Arrhythmias
|
|
|
Major Effects of Lidocaine?
|
Depress Automaticity
Shortens APD and RP No effect on Conduction Velocity |
|
|
How does lidocaine depress automaticity?
|
Dec Phase 4 slope via blocking of slow-leak Na channels
|
|
|
Adverse Effects of Lidocaine?
|
CNS!
Disorientation Convulsions Drowsiness Coma |
|
|
How is lidocaine administered?
|
IV or IM
No PO b/c rapidly metabolized by liver |
|
|
Half life of Lidocaine? so?
|
30 minute to an hour
so its for emergency MI's |
|
|
What is Mexilitine?
|
orally effective congener of Lidocaine
|
|
|
Half life of Mexilitine?
|
~12hrs
|
|
|
Indications for Mexilitine?
|
Ventricular Arrhythmias
Chronic Pain (diabetic neuropathy) |
|
|
Adverse Effects of Mexilitine?
|
GI distress
Tremors Dizziness |
|
|
What is the other use of Phenytoin that we learned?
|
Anti-epileptic
|
|
|
General Properties of Flecainide?
|
-Marked affinity for and blockade of Na Channels
-Marked slowing of Conduction Velocity (shallow phase 0 slope) Little change of APD |
|
|
Uses of Flecainide?
|
Resistant, Life-Threatening Ventricular Arrhythmias
|
|
|
Toxicity of Flecainide?
|
Proarrhythmic, particularly in MI pts
Blurred Vision |
|
|
Cardiac action of Propanolol?
|
Block catecholamine effects, i.e.:
Decease Automaticity Decrease A-V conduction Prolong RP Also have Quinidine-like effects on membranes Depress Conduction Velocity |
|
|
Differences w/ Metoprolol and Esmolol?
|
Metoprolol = mainly Beta-1's
Esmolol - short acting |
|
|
Uses of Beta-Blockers?
|
Paroxysmal Atrial Tachycardia
Arrhythmias ass w/ hyrdrocarbon anesthetics Arrhythmias from tricyclic antidepressants or L-dopa Pheochromocytoma |
|
|
Adverse Effects of beta-blockers?
|
Negative Inotrope
Bronchospasm Depression and Nightmares Rebound sensitivity on withdrawal A-V Block |
|
|
How is Carvedilol different?
|
Beta and Alpha blocker
|
|
|
Action of Class III agents? and examples
|
Prolong RP
Amiodarone Sotalol Dofetilide |
|
|
Main Action of Class IV Agents?
|
Ca Channel Antagonists
(verapamil, diltiazem) |
|
|
Miscellaneous Anti-Arrhythmics?
|
Digitalis
Adenosine |
|
|
Action of Digitalis?
|
Sensitize Baroreceptors to increase vagal tone and depress sympathetic activity to heart
|
|
|
Action of Adenosine?
|
Brief slowing of AV conduction
|
|
|
Actions of Sotalol?
|
Beta blocker that prolongs APD
Blocks K efflux (retards repol) Prolongs APD and RP Beta Blocker=>dec automaticity |
|
|
Adverse Effects of Sotalol?
|
Typical Beta-Blocker SE's
Polymorphic Ventricular Tachycardia (torsades) is possible |
|
|
Half Life of Sotalol?
|
LONG
15ish hours |
|
|
Metabolism of Sotalol?
|
Renal Elimination
|
|
|
Indications for Sotalol?
|
Ventricular Arrhythmias
Maintaining Sinus Rhythm |
|
|
Electrophysiological Actions of Amiodarone?
|
Block K Efflux
Prolong RP of whole heart |
|
|
Adverse Effects of Amiodarone?
|
Yellowish-brown corneal deposits
Slate blue color to skin w/ long use Pulmonary Fibrosis Thyroid Dysfunction Risk of Torsades is less than w/ other K blockers |
|
|
Half Life of Amiodarone?
|
100 DAYS!!!!
|
|
|
Indications for Amiodarone?
|
Resistant, Life=Threatenting Arrhythmias (VT/VF)
Atrial Fib A-V Reentry Arrhythmias ass w/ WPW Syndrome) |
|
|
What is WPW Syndrome?
|
Wolff-Parkinson-White Syndrome
Pts have an accesory A-V conduction pathway (bundle of Kent) that doesn't slow down conduction velocity from atria to ventricles (which the AV node does) |
|
|
What is Dofetilide's main action?
|
its a potent and purer K current blocker => prolonged APD and RP
|
|
|
Adverse Effects of Dofetilide?
|
Long Q-T can lead to Torsades
|
|
|
Pharmacokinetics of Dofetilide?
|
high oral bioavailability and renal elimination
==>close examination of Q-T w/ initial dosing |
|
|
Electrophysiological Actions of Verapamil?
|
Inhibits transmembrane fluxes of Ca-mediated slow response activity (????)
Suppresses Ca fluxes in S-A and A-V nodes --> prolonged AV node RP |
|
|
Adverse Effects of Verapamil?
|
Bradycardias
Complete A-V block Depressed cardiac contraction and hypotension |
|
|
uses of verapamil?
|
Paroxysmal Atrial Tachycardia
Atrial Fib and Flutter A-V Nodal Rhythms |
|
|
Major Action of Diltiazem
|
Ca Channel Blockade in vascular smooth muscle and heart tissue (nodes and myocardium)
|
|
|
Major Effects of Diltiazem?
|
Selective Coronary Vasodilation
Depression of SA and AV nodes Depresses cardiac contractile fxns |
|
|
SE's of Diltiazem?
|
Excessive Bradycardia and AV node blockade
Unwanted reduction in cardiac contractions |
|
|
Two main indications for Digitalis?
|
CHF
Atrial Fib and Flutter |
|
|
Fxns of Digitalis in CHF?
|
Increase force of myocardial contractions
Reduce Peripheral Vascular resistance (afterload) |
|
|
Fxns of Digitalis in A. Fib/Flutter?
|
Increase A-V RP
|
|
|
Electrophysiological Actions of Digitalis
|
Prolong A-V RP via sensitization of baroreceptor-->enhanced vagal tone and dec SNS activity
|
|
|
Therapeutic Action of Digitalis?
|
reduces ventricular rate by making A-V node slow down conduction of atrial impulses
|
|
|
Adverse Actions of Digitalis?
|
Arrhythmias (PVC's, AV block)
Nausea Blurred Vision (w/ halos) |
|
|
Major Actions of Adenosine?
|
Acts on A1 receptors to inhibit adenylate cyclase (dec cAMP)
Activate K currents=>hyperpolarized nodes Slows AV node conduction |
|
|
Onset and Half-Life of Adenosine?
|
Rapid Onset w/ IV (10-20sec)
Very Short Half Life (10 sec) |
|
|
Adverse Effects of Adenosine?
|
Hypotension
Facial Flushing HA Possible "Sx's" of Angina Bronchoconstriction Arrhythmias |
|
|
Indications for Adenosine?
|
Rx of PSVT (nodal reentry)
Dx of supraventricular vs ventricular tachycardia |
