antiarritmicos Flashcards
Cardiac conduction system order
SA node (Sinoatrial node) AV node. (Atrialventricular node) Bundle of HIS Bundle Branches Purkinje Fibers
Cardiac Cells
Cardiac cells, HIS-Purkinje system (Fast response fibers)
Conducting cells, SA node and AV node (slow response fibers)
cuales son los iones principales que participan el la actividad eléctrica del corazón
Sodium
Calcium
Potassium
When the cardiac cells are ______ by an electrical impulse their membranes _______ change and ions _______ ______ the membrane thus generating an _______ ______
stimulated
permeability
move across
Action potencial
membrane potential of SA or AV node (slow response fibbers)
-60mV
Slow response fibers:
When ______ ____ of sodium enters the cell mainly through the slow sodium Chanels.
It opens the voltage-gated _-____ ______ channels continue slow depolarization this is referred to as phase __.
spontaneus flow
T-type calcium
phase 4
threshold for slow response fibers
-40mV
Slow response fibers:
Once the threshold of -40mV is reached the voltage-gated _-______ _____ channels open and calcium rushes in and rapidly depolarize cell to about __mV this is referred as phase __.
L-type calcium
10mV
phase 0.
Slow response fibers:
Once the L-type calcium channels ____ and the voltage gated ________ channels open which allows potassium ions to scape thus repolarizing the cell back to -60 mV referred to as phase __.
close
potassium
phase 3
What is the resting potential of fast response fibers
-90mV
Fast response fibers:
why is the resting potential of fast fiber cells -90 mV
Because of the constant leakage of potassium through the inward-rectifier channels
Fast response fibers:
what happens in phase 4
the resting membrane potential of -90 mV. Due to the constant outward leak of potassium through the inward-rectifier channels.
Fast response fibers:
When an action potential is ______ in a neighboring cell the voltage-gated ____ channels and sodium rushes in causing a rapid depolarization to __ mV these is referred as phase __.
triggered
sodium
40mV
phase 0
Fast response fibers:
When sodium channels become _____ and other voltage-gated channels begin to open, mainly _____ channels will allow potassium to escape thus bringing about a ____ ___ in the membrane potential this is referred as phase __.
inactivated
potassium
small dip
phase 1
Fast response fibers:
During depolarization at phase 0 voltage-gated _-____ _____ channels began to open slowly allowing calcium begin to ____ into the cell so now with the positive potassium ions _____ and the positive calcium ions steadily coming in we have this ________ ______ ion exchange which keeps the membrane potential on a ______ this is referred to as phase __.
t-type calcium enter leaving electrically balanced plateau phase 2
The plateau phase is followed by a rapid _______ referred as phase __ which is caused by gradual ________ of the calcium channels and _________ _______of potassium.
Repolarization
phase 3
inactivation
continuous outflow
types of arrhythmias
bradyarrhythmia (< 60)
tachyarrhythmia (>100)
types of tachyarrhythmias (3)
enhanced automaticity
reentry
triggered activity
type of arrhythmia that ocurres when the cell membrane becomes more permeable to sodium during phase 4 depolarization, this calls cells to acelerate their automaticity and generate faster impulses than the SA node.
enhanced automaticity
Common automaticity stimulants that can cause enhanced automaticity
excess catecholamines
hypoxia
acidosis
isquemic
type of arrhythmia that when the accessory pathway appears, the signal travels through the pathway from ventricles to atria causing them to contract before the SA node fires again, this creates an abnormal loop of electrical activation circulation through a region of heart causing tachyarrithmya
reentry
type of arrhythmia that involves abnormal leakage of positive ions into the cardiac cell leading to this bump on the action potential after the polarization
triggered activity
types of triggered activity
EADs (early afterepolarization)
DADs (delayed afterepolarization)
triggered potential that triggers during prolonged action potentials mainly phase 2
EADs
Are triggered after the action potential is fully repolarized.
DADs
Class of anti arrhythmic drugs that primarily block the rapid inward sodium current, thereby slowing the rate of the rise of the action potential.
Class I
Class 1A anti arrhythmic drugs
Dysopiramid
Quinidine
Procainamid
Class 1B anti arrhythmic drugs
Lidocaine
Mexeletine
Tocainide
Class 1C anti arrhythmic drugs
Morcicine
Flecainide
Propafenone
Class of anti arrhythmic drugs that are b-adrenergic antagonists, which slow the sinus rhythm and slow atrioventricular nodal conduction without substantially changing the Q-T or QRS interval
Class II
Class II anti arrhythmic drugs
Propanolol
Atenolol
Esmolol
Class III anti arrhythmic drugs
Sotalol
Amiodarone
Dofeltide
Class of anti arrhythmic drugs that block the outward potassium current, thus lengthening repolarization and refractoriness
Class III
Class of anti arrhythmic drugs that are primarily calcium channel–blocking agents, which block the slow, inward calcium current and thereby prolong the P-R interval without changing the QRS or Q-T interval.
Class IV
Class IV anti arrhythmic drugs
Diltiazem
Verapamil