Yang Flashcards
direction of conduction system
SA node, atrium, AV node, bundle branches, purkinje fibers, ventricular muscles
what channel should be avoided as a target for new drugs?
hERG, lethal side effects with off target blockade
membrane potential outside the cell
0 mV
membrane potential inside the cell
-70 mV
K+ concentrations inside and outside cell
in: 148 mM
out: 5 mM
Na+ concentrations inside and outside cell
in: 10 mM
out: 142 mM
Ca++ concentrations inside and outside cell
in: <1 uM
out: 5 mM
Cl- concentrations inside and outside cell
in: 4 mM
out: 103 mM
K+ flows which way with electrical gradient
inside
K+ flows which way with concentration gradient
outside
Na+ flows which way with concentration gradient
inside
Na+ flows which way with electrical gradient
inside
pacemaker cells have ____ dependent spikes
Ca++
pacemaker cells contractility
non contractile
pacemaker cells polarization
depolarized
pacemaker cells automaticity
high automaticity
ventricular myocytes have ____ dependent spikes
Na+
ventricular myocytes contractility
contractile
ventricular myocytes polarization
hyperpolarized
ventricular myocytes automaticity
low automaticity
which type of curve is this
pacemaker cell
which type of curve is this
ventricular myocyte
re-entry requirements
multiple parallel pathways
unidirectional block
conduction time greater than effective refractory period
class 1 antiarrythmic
Na+ channel blockers
class 2 antiarrythmic
beta blockers
class 3 antiarrythmic
K+ channel blockers, prolong refractory period
class 4 antiarrythmic
Ca channel blockers
drug class
beta blockers
drug class
calcium channel blockers
beta blockers effects
slow pacemaker and Ca currents in SA and AV node
increase PR interval
which type of arrhthmias are beta blockers good for
involving catecholamines (NE, E)
calcium channel blockers effects
what kind of block?
frequency dependent block
increase refractoriness of AV node
increase PR interval
beta blockers of choice
esmolol
acebutolol
propranolol
esmolol
cardioselective (beta 1), short 1/2 life, IV
calcium channel blockers of choice
verapamil
diltiazem
calcium channel blockers moa and use
frequency dependent block
blocks re-entry arrythmias involving AV node
protect ventricular rate in afib and flutter
class 1A channel block
mixed block, Na+ and K+ channels
class 1A ECG effects
prolonged QT
widen QRS
class 1B channel block
Na+ channel block
class 1B ECG changes
no significant changes
class 1C channel block
strong Na channel block
class 1C ECG changes
widen QRS
which drug class
Class 1A
which drug class
Class 1B
which drug class
Class 1C
Class 1 A drugs
quinidine, procainamide, disopyramide
Class 1B drugs
lidocaine, tocainide, mexiletine, phenytoin
Class 1C drugs
flecainide
propafenone
moricizine
quinadine activity and risk
anti-muscarinic, risk torsade de pointes
lidocaine activity and dosage form
only ventricular
IV only
flecainide activity and dosage form
ventricular and supraventricular
PO
procainamide side effects and activity
lupus like syndrome
ganglionic blocker
disopyramide activty
anti-muscarinic
propafenone activity and dosage form
ventricular and supraventricular
beta blocking
PO
drug class
3 K+ blocker
class 3 moa
block K+ channels and prolong effective refractory period
terminate reentry
Class 3 have high risk of
Torsades De Pointes
class 3 drugs
amiodarone
dronedarone
ibutilide
sotalol
dofetilide
amiodarone action and side effects
suppress emergency ventricular and atrial arrythmias
long half life
hypothyroid, fibrosis, photosensitization
genetic mutations causing long QT syndrome
KCNQ1, KCNH2, SCN5A
0
Na+ in, Class 1 Na blockers
1
K/Cl out
2
Ca in, Class 4 CCBs
3
K+ out, Class 3: K+ blockers
digoxin MOA
inhibition AV node
adenosine action
brief but potent slowing of heart
depress pacemaker cells
widen QRS, 1A 1C
increase PR interval, 2 + 4
widen QT interval, 1A + 3
no change, 1B
