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51 Cards in this Set
- Front
- Back
What is the class of arrhythmic drug that suppresses phase 0 upswing in purkinje and myocardial fibers and shows a marked slowing of condution in all cardia tissues? What is the prototype?
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Class 1c. Prototype, Flecainide
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This drug is used in treatment of various arrhthmias that originate in ventricles of atria.
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Class 1a - Quinidine
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This drug is used in treatment of ventricular arrhythmias arising during myocardial ischemia. It is the drug of choice in emergency treaatment of cardiac arrhythmias and is the least cardiotoxic.
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Class 1b, Lidocaine
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This drug is used in treatment of ventricular arrhythmias such as ventricular tachycardia.
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Class 1c, Flecainide
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What are the Cardiac and Extracardiac effects of Class I Arrhythmic drugs?
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Cardiac: Tendency to aggravate or initiate cardiac rhythm abnormalities while controlling one type of rhythm abnormality (proarrhythmic effect).
Extracardiac: CNS disturbances such as dizziness, nausea and visual disturbances. This drug is used less often and with more caution than before. |
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Cardiac AP is divided into several phases. This phase is a brief period of repolarization due to exit of K+ from cell.
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Phase 1
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This refers to significant deviation from normal cardiac rhythm.
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Arrhythmia
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True or False. Arrhythmia affects 50% of patients treated with digitalis, 25% of anethetized patients, and 70% of pts with acute MI.
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False. Arrhythmia affects 25% of pts treated with digitalis, 50% of anesthetized pts, and 80% of patients with acute MI.
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What are three mechanisms of Cardiac Arrhythmias?
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1. Abnormal automaticity/impulse formation
2. Abnormalities in impulse conduction 3. Simultaneous abnormalities of impulse generation and conduction |
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These type of cells in the sinoatrial (SA) (sinus) node depolarize spontaneoulsly to generate action potential (AP): dominate and control cardiac rhythm in normal heart.
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Pacemaker cells
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AP spread in a timely way through the atria via atrial muscle cells to these.
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AV (Atrioventricular) node
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The bundle of HIS is made up of conducting cells known as ________, which distribute AP ventricular muscle cells.
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Purkinje fibers
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From AV node, AP transmitted to ventricles via specialized conducting system known as what?
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Bundle of HIS
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The fraction delay at the ________ allows time for the atrial contraction that helps fill the ventricles with blood.
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AV node
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This is when the heartrate is <60 beats per minute.
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Bradycardia
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This is when the heart rate is > 100 beats per minute.
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Tachycardia
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Cardiac AP is divided into several phases. This phase is rapid depolarization due to sudden influs of Na +.
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Phase 0
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What are 3 things arrhythmias are named for?
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1. origin
2. nature of disturbed heartbeat 3. impairment of cardiac conduction Example: Ventricular arrthythmias originate in ventricles - Supraventricular arrhythmias origin is in atria, AV node or upper purnje fibers. |
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Name 5 common classifications of arrhythmias?
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1. Sinus arrhythmias
2. Supraventricular arrhythmias 3. Atrioventricular junctional arrhythmias 4. Conduction disturbances 6. Ventricular arrhythmias |
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This classification of arrhythmia involves Sinus tachycardia, sinus bradycardia and/or sick sinus syndrome.
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Sinus arrhythmia
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This classification of arrhythmia can include atrial fibrillation and flutter, atrial tachycardia and premature atrial contractions.
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Supraventricular arrhythmias
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This classification of arrhythmia can include junctional rhythm, and junctional tachycardia.
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Atrioventricular junctional arrhythmias.
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This classification of arrhythmias can include atrioventricular block, bundle branch block, and fascicular block.
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Conduction disturbances
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The classification of these arrhythmias can include, premature ventricular contractions, ventricular tachycardia, and ventricular fibrillation.
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Ventricular arrhythmias.
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These classifications of drugs block Na+ channels
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IA, IB, IC
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These classifications of drugs block beta adrenoreceptors
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II
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These classifications of drugs block K+ channels.
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III
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These classifications of drugs block Ca++ channels.
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IV
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These drugs bind to open (activated) or closed (inactivated) Na+ channels to cause normalization of Na+ entry.
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Sodium channel blockers.
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What is the class of arrhythmic drug that binds to open and inactivate Na+ channels to prevent Na+ influx? What is the prototype?
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Class 1a - prototype Quindine (anti malaria)
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What is the class of arrhythmic drug that blocks both activated and inactivated Na+ channels? It shortens phase 3 repolarization and decreases duration of AP. What is the prototype?
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Class 1b. Prototype, Lidocaine
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Cardiac AP is divided into several phases. This phase is a plateau due to opening of Ca2+ channels, Efflux of K+ ions in hase 1 balances the influx of Ca2+, no net charge-plateau which enables heart to rest and fill with blood - diastole.
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Phase 2
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The cardiac AP is divided into several phases. This phase is when repolarization is completed by unopposed efflux of K+ as Ca2+ channels close.
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Phase 3
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The cardiac AP is divided into several phases. This phase is slow spontaneous depolarization due to leak of Na+ ions into cell plus gradual decrease in K+ exit; accumulation of positive charge causes cell to reach threshold and enter phase 0.
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Phase 4
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This class of antiarrhythmic drugs decrease excitatory effects of sympathetic nervous system, slow down heart rate and contractility (negative chronotropic and ionotropic effect) and conduction through myocardium.
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Class II: Beta-Blockers
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What is the prototype for Class II antiarrhythmic drugs?
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Propranolol (Beta Blocker)
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This class of antiarrhythmic drugs decrease excitatory effects of sympathetic nervous system, slow down heart rate and contractility (negative chronotropic and ionotropic effect) and conduction through myocardium.
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Class II: Beta-Blockers
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True or False - Class II Beta Blockers are not as safe as Class I Sodium channel blockers.
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False, Beta Blockers are safer than Sodium channel blockers.
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One of this antiarrhythmic drugs side effects include othostatic hypotension. A precaution would be to decrease exercise and stress level because of a decrease in HR.
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Class II - Beta Blocker
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This antiarrhythmic drug is used in treatment of arrthythmias originating in atria and AV nodes and is the mainstay in treatment of arrhythmias.
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Class II - Beta Blockers
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What are the cardiac and extracardiac effects of Class III drugs?
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Cardiac = antifibrillatory effect
Extracardiac = beta clockers, therefore potential to cause postural hypotension |
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These drugs have selective ability to block calcium entry into myocardial and vascular smooth muscle cells.
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Class IV - Calcium channel blockers
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This drugs prototype is Nifedipine.
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Class IV - Calcium channel blockers
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This drug decreases the rate of discharge of the SA node and inhibits conduction through the AV node.
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Class IV - Calcium channel blockers
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This drug is used in treatment of arrhythmias cuased by atrial dysfunction such as suproventricular tachycardia and atrial fibrillation.
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Class IV - calcium channel blocker
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What are some non-pharmacological approaches to treatment of arrhythmias?
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Pacemakers, Catheter ablation (destroy tissue contributing to tachycardia), Electrical therapy, Cardioversion (implantable cardioverter defribillator, Surgery
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This drug is used in the treatment of ventricular arrhythmias, ventricular fibrillation supraventricular arrhythmias.
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Class III - K+ Blockers
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This class of antiarrhythic drugs block potassium channels and prolong duration of AP without altering phase 0.
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Class III - K+ Blockers
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The prototype for this anti arrhythmic drug is Sotalol.
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Class III - K+ Blocker
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The advantages to this antiarrhythmic drug is that it affects both atrial and ventricular problems and it is safe compared with Class I drugs.
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Class III K+ blockers
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This class of antiarrthythmic drugs prolong repolarization.
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Class III K+ Blockers
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