Cardiac Arrythmias Flashcards
End Test 2
List the different types of arrhythmias
Bradycardia
Block
-1st degree
-2nd type 1 & 2nd type 2
-3rd degree
Tachycardia
- SVT
-Atrial
-Sinus
-VTach
Fibrillation
-Atrial
-Ventricular
Illustrate the intrinsic conduction system and subsequent EKG reading.
Sinoatrial node/packemaker
-Enforces contraction rate of 75 bpm
-Muscarinic and beta adrenergic input
AV Node
-slow: junction of artia and ventricles
Atrioventricular bundle/bundle of His
-In ventricular septum
Purkinje fibers
-Spread within the muscle of the ventricular walls
P wave
-Atrial depolarization
QRS
-Ventricular depolarization
T wave
-Ventricular repolarization
What is the M gate?
The activation gate on the outter part of the cell
What is the H gate?
The inactivation gate on the inner part on the cell
What is the Recycling period (refractory period)
M gate closes
H gate opens
What happens at Phase 0 in a cardiac AP?
Na reaches membrane potential
Na+ V-G channels open & Na+ rushes into cell
initial depolarization
What happens at Phase 1 in a cardiac AP?
Cell overshoot (Vrm +40)
K+ V-G channels open
K+ leaves the cell
Repolarization starts here
What happens at Phase 2 in a cardiac AP?
Ca++ enters (extends depolarization promoting contraction) – Ca++ channels are much slower
Ca++ influx results in plateau
K+ is still leaving the cell
What happens at Phase 3 in a cardiac AP?
K+ only is leaving the cell
Ca++ channels close
Cell still being repolarized
What happens at Phase 4 in a cardiac AP?
Return to baseline V(rm)
Na/K/ATPase returns normal gradients
Differentiate disturbances in impulse formation and impulse conduction.
Disturbance in impulse formation:
-SA/AV nodal abnormalities
-Ion changes
-Late/early depolarization
-SNS stimulation
Disturbance in impulse conduction: -Block
-Reentry (1 way block - becomes reexcited)
Describe EKG differences in heart block
1st: PR > 0.20 seconds
2nd type 1: Progressive prolongation of PR interval then QRS drops
2nd type 2: PR constant; randomly dropped QRS
3rd: Complete disruption of AV conduction
What 3 things must occur for reentry (circus movement)?
- Obstacle (scar tissue)
- Unidirectional block
- Conduction time must be long enough to reenter same areas after refractory period
Best Tx for type 2 and 3 heart block?
Pacing/pacemaker
What are Class I antiarrhythmias?
Na+ channel blockers
What are Class II antiarrhythmias?
Sympatholytics: Beta Blockers
What are Class III antiarrhythmias?
K+ channel blockers
prolonged action potential duration
What are Class IV antiarrhythmias?
Ca++ channel blockers
Which medication fits into all 4 classes of antiarrhythmias?
Amiodarone
Drugs: Class I antiarrhythmias
Class IA: Quinidine, Procainamide
-Prolong the AP
-Increase effective refractory period
-increases QT
Class IB: Lidocaine
-Shortens AP
-decreases effective refractory period
Class IC: Flecainide
-no effects on ERP
- min effects on AP
Drugs: Class II antiarrhythmias
propranolol
Esmolol
suppress ventricular ectopic depolarization
Drugs: Class III antiarrhythmias
Satolol
Prolong AP by blocking K channel
More K+ inside cell
Drugs: Class IV antiarrhythmias
Verapamil
-prolongs AV conduction
-slows SA node
-Blocks Ca++ channels
Describe the effects of adenosine of SVT.
Enhanced K+ conductance
Inhibition of cAMP induced calcium influx
What is the first line drug for SVT?
Adenosine
What are some additional antiarrhythmias?
Digoxin
Adenosine
Magnesium
Calcium
Potassium
T/F: Adenosine has a long half life
F
List non-pharmacological therapy for arrhythmias.
Vagal maneuvers
Pacemakers
Cardioversion
Ablation
Surgery
Tx: Bradycardia
Symptomatic: Atropine
Chronic: Pacemaker
Tx: Heartblock
Symptomatic: Atropine/Transcutaneous pacing
Chronic: Pacemaker
Tx: SVT
Symptomatic: Adenosine/transcutaneous pacing
Chronic: CCB, Beta Blockers
Tx: Sinus Tach
Symptomatic: Adenosine, CCB, Cardiovert
Chronic: Cardiac Ablation
Tx: VTach (wide complex)
Symptomatic: Amiodarone
Chronic: Amiodaron, Satolol
Tx: Afib
Symptomatic: Diltiazem, Verapamil
Chronic: Beta blockers, Amiodarone
Tx: Vfib
Symptomatic: CPR, Defib
Chronic: Amiodarone, lidocaine
