Flashcards in Arrhythmias Deck (40)
What are the two classes of arrhythmias described by where the arrhythmia arises?
Supraventricular arrhythmias tend to have narrow QRS complexes. True/False?
Because the arrhythmia does not originate from ventricles
The AV node is the only point of electrical contact between the atria and ventricles. What may additionally be present to cause pathological conduction?
What are ectopic beats?
Beats/rhythms that originate outwith the SA node
Ectopic beats may not be dangerous. True/False?
Why might ectopic beats not be harmful?
Depends on where they originate - if in non-contractile areas, they are unlikely to affect cardiac output
Name the main supraventricular arrhythmias
SVTs: atrial fibrillation, atrial flutter, ectopic atrial tachycardia
Bradycardias: sinus bradycardia, sinus pauses
Name the main AV node arrhythmias
AV node reentry
AV block (1st, 2nd, 3rd degree)
Name the main ventricular arrhythmias
Premature ventricular complex
What are the 3 main physiological types of arrhythmia?
Reentry (accessory pathway)
List the investigations you would do for arrythmias
ECG/exercise ECG/24hr ECG
EP study (induce arrhythmia to map pathway)
How would acute SVT be managed?
Vagal manoeuvres, carotid massage
Give examples of some vagal manoeuvres
Holding your breath and bearing down (Valsalva)
Immersing face in ice-cold water (diving reflex)
Holding nose/unblocking ears
What is the treatment of choice for managing chronic arrhythmias?
What is radiofrequency ablation?
Selective cauterisation of cardiac tissue to prevent tachycardia
Target reentry circuit or automatic myocite
Which drugs must be stopped before radiofrequency ablation?
Antiarrhythmic drugs 3-5 days beforehand
What is notorious for causing AV block in young people?
Describe 1st degree AV block
PR interval increased (greater than 0.2s)
Describe 2nd degree Mobitz 1 AV block
PR interval gets progressively longer, followed by dropped QRS
Describe 2nd degree Mobitz 2 AV block
Lonely P waves not followed by QRS
N.B. PR interval not prolonged
Describe 3rd degree AV block
P waves without QRS complexes
i.e. no association between atrial and ventricular systole
What is typical of an ECG showing ventricular tachycardia?
Broad QRS complexes
What is the difference between monomorphic and polymorphic VT?
In monomorphic VT, the QRS complexes look similar
How would acute VT be treated?
DC cardioversion if unstable
Adenosine if unsure it's VT
What are the 3 classifications of AF?
Define paroxysmal AF
Recurrent AF, lasting less than 48 hours
Define persistent AF
AF lasting greater than 48 hours which can be cardioverted to normal sinus rhythm
Define permanent AF
AF that is unable to be restored to normal sinus rhythm via pharma + non pharmacological methods
What is meant by lone AF?
AF where a cause cannot be found
What would a typical ECG of AF show?
Rate greater than 300bpm
P waves absent
What are the two management pathways for AF patients?
Rhythm control (get back to NSR)
Rate control (accept AF, control ventricular rate)
What pharmacological therapy can be used for rate control in AF?
How can NSR be restored in AF (rhythm control)?
Class I anti-arrhythmic drugs act on which phase of the AP and block which channels?
Act on phase 0
Block Na+ channels
Name a class I anti-arrhythmic drug
Class II anti-arrhythmic drugs act on which phase of the AP and block which channels?
Act on phase 4
Block B receptors (B blockers)
Class III anti-arrhythmic drugs act on which phase of the AP and block which channels?
Block K channels
Name a class III anti-arrhythmic drug
Class IV anti-arrhythmic drugs act on which phase of the AP and block which channels?
Block Ca channels