objective 2.2 (pt.3) (1) Flashcards
is any deviation from the normal rhythm of the heart
dysrhythmia
used for the treatment and prevention of disturbances in cardiac rhythm
antidysrhythmic
how do we pick up on dysrhythmias?
An electrocardiogram (ECG or EKG) records the electrical activity as it passes through the heart muscle
P wave, PR interval, QRS complex, ST segment, T wave
above the ventricles and includes:
Atrial fibrillation
supraventricular dysrhythmias
in the ventric;es and include
AV block
Bundle branch block (his-Purkinje fibers block)
PVCs (premature ventricular contractions)
Ventricular tachycardia
ventricular dysrhythmias
what are the vanughan williams classifications?
Class I- Na channel blockers
Class Ia
Class Ib
Class Ic
Class II- beta blockers
Class III- K channel blockers
Class IV- Ca channel blockers
Unclassified
Membrane-stabilizing drugs; fast sodium channel blockers
Divided into Ia, Ib, and Ic drugs, according to effects
class I: Na channel blockers
Block sodium (fast) channels, delay repolarization, increase action potential duration (APD)
Used for atrial fibrillation, premature atrial contractions, premature ventricular contractions, ventricular tachycardia, Wolff-Parkinson-White syndrome
class Ia
Block sodium channels, accelerate repolarization, increase or decrease APD
Lidocaine is used for ventricular dysrhythmias only
Phenytoin is used for atrial and ventricular tachydysrhythmias caused by digitalis toxicity or long QT syndrome
class Ib
Block sodium channels (more pronounced effect), little effect on APD or repolarization, used for severe ventricular dysrhythmias
May be used in atrial fibrillation or flutter, Wolff-Parkinson-White syndrome, supraventricular tachycardia dysrhythmias
class Ic
Reduce or block SNS stimulation, thus reducing transmission of impulses in the hearts conduction system
They are general myocardial depressants for both supraventricular and ventricular dysrhythmias
Also used as antianginal and antihypertensive drugs
B-blockers
β-blocker blocks β1 adrenergic receptors that are located primarily in the heart
Usees: antidysrhythmic, hypertension, and angina
Contraindications: severe bradycardia, second (AV) or third (SA) degree heart block, HF, cardiogenic shock, or a known hypersensitivity
atenolol
Increase APD
Prolong repolarization in phase 3
Used for dysrhythmias that are difficult to treat
Life-threatening ventricular tachycardia or fibrillation, atrial fibrillation or flutter that is resistant to other drugs
amiodarone, dronedarone, sotalol, ibutilide
the drug of choice for ventricular dysrhythmias
Most serious effect: is pulmonary toxicity with lung damage
Other AE: ocular issues including corneal microdeposits with halos, photophobia, and dry eyes
amiodarone
Inhibit calcium-dependent pathways in the heart
Therefore, they reduce atrioventricular node conduction
Used for paroxysmal (sudden return of symptoms) supraventricular tachycardia, and rate control for atrial fibrillation and flutter
Examples: verapamil & Cardizem
calcium channel blockers
