Pharmacology - Chapter 48 - Antidysrhythmic Drugs Flashcards
Dysrhythmia - def
abnormality in rhythm of the heartbeat.
In mildest forms of dysrhythmia, there are only ___ effects on cardiac output.
In severe forms, they can ___ the heart so that ___ cardiac output occurs.
Mild effects.
Disable.
No.
What are the 2 types of dysrhythmias?
Tachydysrhythmias and Bradydysrhythmias.
Drugs that treat dysthythmias can cause them. T/F?
True!
In healthy heart - impulse originates at ___ node, spreads rapidly through ____, passes slowly through __ node, spreads rapidly through the ___ via the ____ ___ ___.
SA Node
Atria.
AV node.
ventricle via the His-Purkinje System.
EKG - P wave =
depolarization in atria (atrial contraction.)
QRS Wave =
depolarization of ventricles (ventricular contraction.)
T-wave =
repolarization of ventricles (not associated with physical activity of heart.)
PR wave - represents the time between…
onset of the P wave and onset of the QRS complex.
Prolongation of the PR wave indicates….
delayed AV conduction.
QT Wave - the time between onset of the ….. and the completion of the….
QRS complex and completion of the T Wave.
QT prolongation indicates….
delayed ventricular repolarization.
What are the two types of disturbances that can generate dysrhythmias?
Disturbances of impulse formation (automaticity)(Sa or AV nodes) and Disturbances of conduction (like an AV block.)
What are the two major groups of Dysrhythmias?
Supraventricular and Ventricular!
Supraventricular Dysrhythmias - where do they come from? And what are some?
Impulses arise above the ventricule, like SVT (Supraventricular Tachycardia), Atrial flutter, A Fib, etc.
Ventricular Dysrhythmias - they are less dangerous than Supraventricular Dysrhytmia - T/F?
False! They are more dangerous!
What are some ventricular Dysrhythmias?
Ventricular Tachycardia, Ventricular Fibrilation, and Ventricular Premature Beats (VPB)
What are the Vaughan Williams Classifications?
Class 1-4.
Class 1 - blocks sodium channels and delays ventricular repolarization (Quinidine.)
Class 2 - beta blockers (Propanalol.)
Class 3 - potassium channel blockers, delay repolarization (Bretylium.)
Class 4- calcium channel blockers; reduces SA node activity (Cardizem.)
Others - Digoxin.
Class 1A Agents - What is the drug?
Quinidine - Cinchona alkaloid, blocks sodium channels,delays repolarization.
What are the adverse effects of Quinidine?
Diarrhea, Cinchonism, Cardiotoxicity.
Class 1 B Agents - Drug
Lidocaine (Xylocaine) - Blocks sodium channels, reduces automaticity in ventricles, accelerates repolarization.
What are the adverse effects of Lidocaine?
CNS effects, confusion, paresthesias (Paresthesia is a sensation of tingling, tickling, prickling, pricking, or burning of a person’s skin with no apparent long-term physical effect.)
Class 2 Beta Blockers - What is the drug?
Propanalol - a nonselective beta adrenergic. It is used for tachydysrhythmias.
What are the adverse effects of propranolol?
Bronchospasm, heart failure, av block, and sinus arrest.
Class 3 Potassium Channel Blockers - what is the drug?
Bretylium. It delays repolarization of fast potentials. The QT interval is prolonged. It is used for Ventricular Tachycardia and V Fib.
What is the adverse effect of Bretylium?
Profound hypertension.
Class 4 Calcium Channel Blockers - Drug/what does it do, etc.
Verapamil - Reduces SA nodal automaticity, delays av nodal conduction, reduces myocardial contractility…it is used for SVT Atrial flutter, atrial fibrilation…
What are the adverse effects of Verapamil -
Bradycardia, AV block, Heart failure.
