Antidysrhythmic Drugs - Ch. 52 Flashcards
What is a dysrhythmia?
Any deviation from the normal rate/rhythm of the heart
What is an arrhythmia?
βno rhythmβ
What is Asystole?
No heartbeat
What are tachydysrhythmias?
Increased heart rate
-More common
-treated with drugs and other stuff
What are bradydysrhythmias?
Slowed heart rate
Electrical pacing
-Treated with Atropine
What caused dysrhythmias?
Ischemic heart disease
MI
Cardiomyopathy
myocarditis
electrolyte imbalanses (e.g, abnomral K+ level)
What are antidysrythmics?
Drugs used for the treatment and prevention in cardiac rate and/or rhythm
Most antidysrythmics do what?
Supress abnormal electrical impulse formation or conduction
What produces cardiac electrical activity?
SA node cells
AV node cells
Purkinje fibres cells
Ventricular cells
-Electrical activity differs with each cell type
What results in action potential in cardiact muscle?
Movement of ions across the cardiac cell membranes
What does action potential cause the contarction of?
Myocaridal muscle
In SA and AV node cells what does action potential depend on?
Ca2+ influx via calcium channels
In ventricular/atrial cardiac muscle cells how does action potential start?
With Na+ influx (depolarization) via sodium channels
In ventricular/atrial cardiac muscle cells how does action potential end?
K+ efflex (repolarization) via potassium channels
What are the symptoms of dysrhythmias?
Palpitations
Dizziness
Fainting
Dyspnea
or asymptomatic sometimes
What is the HR of someone with supraventricular tachycardia?
120-250 beats/min
What are the kinds of supraventricular tachycardia?
Paroxysmal
Persistent
Permanent
Atrial flutter
Atrial fibrillation
What is Paroxysmal supraventricular tachycardia?
Episodic, starts suddenly and returns to normal within ~24 hours
What is Persistent supraventricular tachycardia?
Episodes last longer than 7 days
Usually treatment is needed to return the heart to a normal rhythm
What is Permanent supraventricular tachycardia?
dysrhythmia lasts for more than a year despite medications and other treatments
What is the most common supraventricular tachycardia type?
Atrial fibrillation
What is Ventricular tachycardia (VT)?
problem with ventricular muscle
How long is non-sustained VT?
<30sec
How long is sustained VT?
> 30sec
What do supraventricular dysrythmias affect?
Ventricular contraction rate
-A-V block desireable
What dysrhythmias are more dangerous?
Ventricular are more dangerous than supraventricular
How is the large variety of antidysrhythmic drugs classified?
Vaughan Williams classification