Arterial fibrillation Flashcards
what is AF?
- chaotic and disorganised atrial activity
- irregular heartbeat
- can be paroxysmal, persistent or permanent
- most common sustained arrhythmia
- can by symptomatic or asymtomatic
- incidence increases with age
what is the mechanism of AF?
- ectopic foci in muscle sleeves in the ostia of the pulmonary veins
how is AF treated?
termination
- pharmacologic cardioversion with anti-arrhythmic drugs (30% effective)
- electrical cardioversion (op% effective)
- spontaneous reversion to sinus rhythm
what are the forms of AF?
- paroxysmal
- persistent
- permanent
what is paroxysmal AF?
- paroxysmal and lasting less than 48 hours
- often recurrent
what is persistant AF?
- an episode of AF lasting greater then 48 hours which can still be cardioverted to NSR
- unlikely to spontaneously revert to NSR
what is permanent AF?
- inability to pharmacologic or non-pharmacologic methods to restore NSR
what are disease/causes associated with AF?
- hypertension
- congestive heart failure
- coronary artery disease
- obesity
- alcohol abuse
- congenital heart disease
- COPD pneumonia
what is lone (idiopathic) AF?
- absence f any heart diseases and no evidence of ventricular dysfunction
- could be genetic
- significant stroke rate > 75 years of age
what are the symptoms of AF?
- palitations
- pre-syncpoe
- syncope
- chest pain
- dyspnea
- sweatiness
- fatigue
symptoms often worse at the onset of AF
what would the ECG show for AF?
- atrial rate >300bmp
- irreglarly irregular rhythm
- variable ventricle rate based on AV node conduction properties, sympa and para tone, presence of drugs which act on the AV node
- absence of P Waves
- presence of f waves
what may be required for AF with a slow ventricular rate?
- a pacemaker to allow for pharmacologic control of fast VR
when is AF most likely to result in congestive heart failure?
- in the presence of diastolic dysfunction
what does a bmp <60 suggest?
- AV conduction disease
- caution with anti-arrhytgmic and rate controlling drugs
- may require permanent pacing
how is AF managed?
- maintain SR
Or - accept AP but control ventricular rate
- anticoagulation for both approaches if high risk for thromboembolism
how do we control rate in AF?
- pharmacologic therapy to slow doen AVN conduction
- digoxin
- betablcokers
- verapamil, diltiazem
how is rhythm controlled in AF?
- restoration of NSR = pharmacologic cardioversion (anti-arrythmic drugs eg aminodarone) and direct current cardioversion
- maintenance of NSR = anti-arrhythmic drugs, catheter albation of arial focus/pulmonary veins, surgery
what are class 1 antiarrythythic drugs?
- reducing Na channel current
Lignocaine, quinidine, flecainide, propafenone
what are class 2 anti arrhythmic drugs?
- B-Adrenergic antagonists
Propranalol
what are class 3 anti arrhythmic drugs?
- action potential prolongation
Amiodarone, sotalol
DRONEDARONE
what are class 4 anti arrythmic drugs?
- Ca channel antagonists
Verapamil
what is torsades de pointes? (TdP)
- heart rate 200-250 bmp
- irregular rhythm
- long QT interval
- wide QRS
- continously changing QRS morphology
whats the indications for anti-coagulation in AF?
- valvular AF = mitral valve disease: MS and MR
- non valvular AF is >75, hypertension, heart failure, previous stroke, CAD, diabetes
what is atrial flutter?
- rapid and regular form of atrial tachycardia
- usually paroxysmal
- sustained by a macro-reentrant circuit
- circuit is confined to the right atrium
- episodes can last from seconds to years
- chronic atrial flutter usually progress to atrial fibrillation
