Arrhythmia Flashcards
Define Arrhythmia
• abnormal rhythmic of the heart
• issues with generating impulses
What are the types of arrhythmias?
• bradycardia: <60bpm
• tachycardia: 100-150bpm
• flutter: 150-350bpm
• fibrillation: 350bpm
What can disrupt heart rhythm?
• drugs
• inflammation
• trauma
• electrolyte imbalance
• hypoxia/ischaemia
Define Ischaemia?
Reduced flood flow to tissue
• low levels of nutrients and energy
• high levels of waste products (lactic acid)
Define Hypoxia?
Reduced oxygen supply to tissue, regardless of blood flow
Hypoxemia = reduced oxygen supply, leading to hypoxia if severe
What are the 3 mechanism of Arrhythmia?
• inappropriate automaticity
• triggered activity
• re-entry mechanisms
Describe inappropriate automaticity
• usually the cells of the SA have the ability to generate spontaneous AP - (automaticity)
• however, here other cells of the heart, which shouldn’t act as pace makers, generate their own impulses
Describe Triggered activity?
• Early afterdepolarisation - abnormal depolarisation occurs during the repolarisation phase - linked with QT syndrome
• Delayed afterdepolarisation - abnormal depolarisation, which occurs after the repolarisation phase - linked with increases Ca levels
Describe Re-entry mechanism
• electrical impulses travel on a circular pathway
• ectopic depolarisation occurs
ectopic = electrical impulses originating from abnormal location
What is the cause of sinus tachycardia?
• increase sympathetic activity
• decreased parasympathetic activity
• hypotension
• hypothyroidism
What is the treatment of sinus tachycardia?
• CCB’s
• oxygen
• bed rest
What is the cause of sinus bradycardia?
• increased parasympathetic activity
What is the treatment of sinus bradycardia?
Anticholinergics
^ they block the action of acetylcholine (which increases HR)
What is Premature atrial contractions & its treatment?
? = Extra heart beats, originating from atria
Treatment = CCBs or digoxin
What is the mechanism of Atrial flutter
Re-entry
Define AV block
A blockage/delay of electrical signals from atria to ventricles
Define 1st degree AV block
Prolonged PR interval
Define 2nd degree AV block
Here some of the electrical impulses fail to conduct from atria to ventricles
Mobtiz type 1 (wenckabach) = progressive lengthening of PR interval
Mobtiz type 2 =
• non conducted p wave
• consistent PR interval
Define 3rd degree AV block & it’s treatment
• no impulses conducted from atria to ventriculas
• treatment = pacemaker
What are the triggers of premature ventricular contractions
• alcohol
• caffeine
• stimulant drugs
• Illicit drugs
• sympathetic activity - stress and exercise
What are the characteristics of Wolf-Parkison-White syndrome
• tachycardia
• short PR interval
• wide QRS
• bypasses the AV node
