Pharmacology Anti-Arrhythmic 1 Flashcards
DAD stands for
delayed afterdepolarization
EAD stands for
early after-depolarization
ERP stands for
effective refractory period
define arrhythmia
abnormal heart rhythm/rate affects cardiac output
_________ increases risk for stroke and heart failure
arrhythmia
What are the different causes of arrhythmia?
genetic - wolff parkinson white syndrome
drug induced - digitalis
anesthetized patients
heart dysfunction/ acute mi
What are some nonpharmacologic therapies?
pacemakers
cardioversion
catheter ablation
surgery
What is bradycardia?
slow heart beat
less than 60 bpm is
bradycardia
more than 100 bpm is
tachycardia
what is normal sinus rhythm?
between 60 to 100 bpm
tachycardia is
rapid heart beat
an abnormality in impulse initiation and/or impulse propagation
arrhythmia
what are the three types of atrial arrhythmias?
premature atrial contractions
paroxysmal atrial tachycardia
atrial fibrillation
a premature atrial contraction triggerering a flurry of atrial activity, with ventricles still able to keep pace and the heart rate jumping to 180 bpm is known as
paroxysmal atrial tachycardia
impulses moving over the arial surface at rates of perhaps 500 beats per minute with quivers instead of an organized contraction is known as
atrial fibrillation
what are the types of ventricular arrhythmia
premature ventricular contractions
ventricular tachycardia
ventricular fibrillation
what type of atrial arrhythmias occur in often healthy individuals
PACs
what is known as a surprise atrial contraction
PACs
what increases incidences of PACs
stress, caffeine, and various drugs
what type of ventricular arrhythmia occurs when a purkinje cell or ventricular myocardial cell depolarizes to threshold and triggers a premature contractions
PVCs
which cell is responsible for PVCs
ectopic pacemaker
what arrhythmia is defined as four or more PVCswithout intervening normal beats
ventricular tachycardia
what arrhythmia is responsible for cardiac arrest
ventricular fibrillation
T or F VF is rapidly fatal, because the ventricles quiver and stop pumping blood
T
torsades de pointes is a type of
V tach
what does torsades de pointes mean
polymorphic ventricular tachycardia
what are the ion movements of the NA K ATPase pum
1 ATP pumps out 3 Na+= and 2 K+
What is the ion movement of the Na+ Ca++ exchanger
3 Na + in, 1 Ca++ out
electrical activity of the heart is maintained by
pumps
ion channels
autonomic nervous system
what is the mechanism of arrhythmias
distrubance of impulse formation
which class of anti arrhythmic drugs decrease phase 4 slope?
class 2
what class of antiarrthymic drugs increase threshold?
class 1 and class 4
what class of antiarrthymic drugs increase the maximum diastolic potential
adenosine and acetylcholine
what class of antiarrhythmic drugs increase action potential duration?
class 3
what are two ways to increase refractoriness?
in early after depolarization and delayed afterdepolarization
what are some examples of class III drugs?
amiodarone
dofetilide
sotalol
what are some examples of class II drugs
beta blockers like propranolol, atenolol, metoprolol
what are some examples of class IV drugs
non DHP calcium channel blockers like verapamil and diltiazem
what is the mechanism of action of class I drugs?
sodium channel blockade
which class of drugs reduces phase 0 slope and peak of AP
class I
which subclass of class I drugs are moderate
A
which subclass of Class I drugs are strong
C
which subclass of class I drugs are weak
B
which class of drugs has a moderate reduction in phase 0 slope with an increased APD
IA
which class of drugs reduced APD
IB
which class of drugs has no effect on APD
IC
what is the mechanism of action of Class II drugs
beta blockade, blocks sympathetic activity, reducing rate and conduction
what is the mechanism of action of Class III drugs
potassium channel blockade
what class of drugs has delay repolarization in phase 3 thereby increasing APD and ERP
class III
what is the mechanism of action of class IV drugs
calcium channel blockade
which class of drugs blocks L type calcium channels and is most effective at the SA and AV nodes, reducing rate and conduction
class IV
what are the Class IA drugs?
procainamide
quinidine
disopyramide
what are the Class IB drugs
lidocaine
mexiletine
what are the class IC drugs
flecainide
propafenone
which class I subclass dissociates with the channel with rapid kinetics?
IB
which class I subclass dissociates with the channel with intermediate kinetics?
Class IA
which class I subclass dissociates with the channel with slow kinetics?
class IC
procainamide is effective against
most atrial and ventricular arrhythmias
WPW syndrome
what are the cardiac effects of procainamide?
slows the upstroke of the AP
slows conduction
prolongs the QRS duration of ECG
prolongs the APD - class 3
has direct depressant actions on SA and AV nodes
all 1a show reverse use dependence
what are the extracardiac effects of procainamide?
has ganglion blocking properties and causes hypotension
what are the dosage forms of procainamide?
oral
iv - slow infusion
im
how is procainamide metabolized?
hepatic
NAPA - n acetyl procainamide
NAPA has class _ effects causing
3
torsades de pointes
how is procainamide excreted?
renally
T or F procainamide does not need dose adjustment for patients in renal or heart failure
F , needed because eliminated renally
who is contraindicated for procainamide
hypersensitivity
CHF
renal failure
shock patients
are there DDI concerns with procainamide?
YES
potentiate cardiac effects of beta blockers
hypotensive effect of thiazides
anticholinergic effects
neuromuscular blocking effects
what are the toxicities of procainamide
cardiotoxicity
immunity issues
blood dyscrasia
pulmonary toxicity
what are the cardiotoxicity effects of procainamide?
excessive action potential prolongation
QT interval prolongation
induction of torsades de pointes arrhythmia
syncope
1/3 of patients who take procainamide experience immune toxicities, what is that?
lupus erythematosus, arthralgia and arthritis
what kind of toxicities, blood dyscrasias, does procainamide have?
agranulocytosis
bone marrow depression
neutropenia
hypoplastic anemia
thrombocytopenia
