Antiarrhythmic Drugs Flashcards
Difference between automaticity and conduction
Automaticity - origin of pacemaker activity (impulse) - should be SA NODE
Conduction - defined path of an impulse
Singh-Vaughan Williams Classification
Classes: I: sodium channel blockers - UPSTROKE II: beta adrenoceptor blocker III: potassium channel blockers - REPOLARIZATION IV: calcium channel blockers - PLATEAU
What is Torsades de pointes?
Prolonged QT interval with variable shape of AP
ECG finding: POLYMORPHIC VENTRIC TACHY
Subgroups in CLASS 1 antiarrhythmic drugs
Group
1A prolong AP duration
1B shorten AP duration
1C no effect on AP duration
MOA of group 1A antiarrhythmic drugs
Slow or block conduction in ischemic and depolarized cells
Slow or abolish abnormal pacemakers
Depress tis. Frequently depolarizing
Depress tis. that relatively depolarizes during rest
Most commonly used antiarrhythmic drug with group 1A activity
Amiodarone
Class 1A antiarrhythmic used for arrhythmias esp after MI but causes LUPUS-LIKE syndrome (DRUG-INDUCED LUPUS)
Procainamide
Hyperkalemia exacerbates cardiac toxicity
Class 1A antiarrhythmic used for arrhythmias that causes cinchonism (headache vertigo and tinnitus), arrhythmia (Torsades) and ITP
Quinidine
Reduces clearance of digoxin
Class 1A antiarrhythmics
1 Am the QUeen who PROclaimed DISO PYRAMID
QUinidine
PROcainamide
DISOPYRAMIDe
Treatment of Class 1A antiarrhythmic overdose
Sodium lactose for arrhythmia
Pressor sympathomimmetic for hypotension
Class 1B Antiarrhythmics
1B Is Best postMI
MEXican Taco from LIly
MEXiletine
Tocainide
LIdocaine
What are the drugs that can cause agranulocytosis?
Agranulocytosis CCCAAPPIT!!! Clozapine Co-trimoxazole Colchicine Aminopyrine Phenylbutazone PTU Indomethacin Tocainide
Least cardiotoxic among conventional antiarrhythmics
Lidocaine
DOC for ventricukar arrhythmias postMI and digoxin-induced arrhythmias
Lidocaine
SimD: Mexiletine, Tocainamide, Phenytoin*
SE: CNS stimulation, CV depression, arrhythmias
IMPT SE: Agranulicytosis for Tocainamide
Class 1C antiarrhythmic used for REFRACTORY ARRHYTHMIAS that is known to cause MORE arrhythmias and BRUGADA SYNDROME
Flecainide
SimD: Propafenone, Encainide, Moricizine
Ch1Cken ay Pagkain For Enrico
Class 1B antiarrhythmic drugs
1C Is Contraindicated postMI
Ch1Cken ay Pagkain For Enrico Propafenone Fleicanide Encainide Moricizine
Antiarrhythmic drugs used in WPW syndrome
Procainamide and Amiodarone
Both with class 1A activity
Class 2 antiarrhythmic that has an effect on phase 4 is manifested in ECG as
Prolonged PR Interval
Due to beta-adrenoceptor blockade and reduction in cAMP
Group 2 effects shown also by SOTALOL and AMIODARONE
Class 2 antiarrhythmic drugs used as postMI prophylaxis against sudden death, and used as well in thyrotoxicosis
Propranolol, metoprolol, timolol
SE: bronchospasm, etc.
Beta blcker with class 3 antiarrhythmic property
Sotalol
Beta blocker with the shortest halflife which is used in ACUTE PERIOPERATIVE AND THYROTOXIC ARRHYTHMIAS and SVT
ESMOLol
SMOL - maliit na halflife
Class 3 antiarrhythmic drugs
Seen as inc in QT Interval on ECG
Class 3 antiarrhythmic drug used for AF as Tx and prophylaxis
Dofelitide
SimD: Ibutilide
dOFelitide for AF
SE: Torsades de Pointes
Only class 3 antiarrhythmic drug that is a beta blocker also used for SVT, ventric arrhyth and AF
Sotalol
Class 3 antiarrhythmic drugs that is most efficacious of all antiarrhythmics
Amiodarone
SimD: Dronedarone
SE: Pulmonary fibrosis, Opthalmologic sx (corneal deposits), Thyroid dysfunction
Class 3 antiarrhythmic drugs
Prolonds AP duration by delaying repolarization, manifested as inc QT interval on ECG
AIDS Amiodarone Ibutilide Dofetilide Sotalol
Why are Dihydropyridine CCBs not useful as an antiarrhythmic drug?
It evokes compensatory discharge which promotes more arrhythmias
PROARRHYTHMIC THAN ANTIARRHYTHMIC
Class 4 antiarrhythmic drugs
Dec AV conduction velocity and ERP
ECG: PR interval consistently increased
Verapamil, Diltiazem
Miscellaneous antiarrhythmic used as DOC for PAROXYSMAL SVT
Adenosine
SE: flushing
