Arrhythmias Flashcards
Give some causes of arrhythmias
IschaemiaLV aneurysmMitral valve diseaseElectrolyte disturbances Abberant conduction pathways CardiomyopathyPericarditisMyocarditisAlcohol Smoking
What are the four different ways that you can classify an arrhythmia?
Rhythm - regular vs irregularRate - fast vs slowSite of origin - supraventricular vs ventricularComplexes on ECG - wide vs narrow
What are arrhthymias commonly due to, electrically?
Re-entry Abnormal automaticityHeart block
What is needed for re-entry rhythm to occur?
- An area of unidirectional block (such as an accessory pathway) or slow conduction block - Time taken to propagate impulse around the ring of tissue must exceed the time of the refractory period of the heartThis causes a continuous circulation of the impulse, called a circus movement
Define abnormal automaticity
The ability for the pacemaker potential to arise in a different area of the heart, other than the SAN.
Why does heart block occur?
Ischaemia causing damage to a variety of structures:- SAN block- AVN block - Bundle branch block - Hemi block
Describe supraventricular tachycardia
Regular rhythmRate is not controlled by SAN - abnormal conduction overrides SANThis abnormal conduction arises from somewhere in the atria
What are the three most common supraventricular tachycardias?
ANVRT - atrioventricular node reentrant tachycardiaAtrial tachycardiaAVRN - Atrioventricular reentrant tachycardia
Describe atrial fibrillation
Chaotic, irregular rhythmSAN is not controlling the rate (no p waves)Atria depolarise at 300-600 bpm, with the AVN occasionally responding
What is the main risk with having AF?
Embolic stroke
Give some causes of AF?
MI Heart failureHypertensionMitral valve disease pneumoniaAlcoholHyperthyroidism
How can AF be classified?
Paroxysmal - self-terminatingPersistent - can be converted to sinus rhythmPermanent - unable to maintain sinus rhythm
