AFib Flashcards
pathophysiology?
- atrial ectopic beats (automaticity foci) thought to originate in pul veins –> lead to uncontrolled contraction of atria & irregular, fast, fibrillatory activity (300-600bpm) which also leads to irregular contraction of ventricles
- due to the irregular contractions, atria fail to empty adequately & blood pools there–> risk of clot formation
symptoms?
- often asymptomatic
- dizziness
- palpitations
- SOB
- collapse
signs?
- irregularly irregular pulse
- pulse deficit
- fast AF–> loss of diastolic filling –> no detectable pulse
- signs of LVF
DDx for irregularly irregular pulse?
- AF
- Ventricular ectopics
can be differentiated w ECG
what are ventricular ectopics & how do they present?
- premature ventricular beats caused by random electrical discharges from outside atria
- presents as random, brief palpitations
- disappear when HR gets over a certain threshold
aetiology of ventricular ectopics
- common at all ages and in healthy patients
- more common if pre-existing heart condition
diagnosis of ventricular ectopics?
individual random, broad QRS complexes on the background of a normal ECG
Ix & findings on ECG?
- Bloods
- ECG
- no P waves
- narrow QRS
- irregularly irregular ventricular rhythm
- undulating baseline
classification of AF
- valvular
- moderate/severe MS too
- non-valvular
- any other valvular pathology or none at all
aetiology? mnemonic
MRS SMITH
Sepsis
Mitral valve pathology
IHD
Thyrotoxicosis
Hypertension
also…
- Lung disease- PE/Pneumonia
- Alcohol
- ASD
complications?
- risk of stroke
- clot embolise to brain–> ischaemic stroke
- HF due to poor filling of ventricles
- sudden death
types of AF?
- paroxysmal
- persistent
- permanent
what is paroxysmal AF
- recurrent episodes
- terminates spontaneously within 7 days
what is persistent AF?
lasts >7 days, requires termination by pharamcological or electrical cardioversion (may still recur after this)
what is permanent AF?
- refractory to cardioversion
- sinus rhythm cannot be restored or maintained
- AF is accepted as final rhythm
main principles of Rx
- rate /rhythm control
- anticoagulation
Mx of paroxysmal AF
Rx: pill in pocket (flecainide) + anticoagulation
prevention: beta blocker/amiodarone/sotalol
Mx of acute AF (<48h)
- haemodynamically unstable
- emergency electrical cardioversion
- no haemodynamic instability
- Rate control (or rhythm control)
- aim is <100bpm
- if no spontaneous conversion to sinus rhythm:
- start LMWH
- immediate cardioversion (electrical or pharmacological)
- Rate control (or rhythm control)
Mx of persistent AF?
- rate control, unless
- reversible cause for AF
- AF is of new onset
- AF is causing HF
- they remain symptomatic despite being effectively rate controlled
if any of above circumstances, offer rhythm control
options for rate control?
- beta blockers- metoprolol
- rate limiting CCB - Verapamil
- not preferable in HF
- Digoxin
- only in non-paroxysmal AF & if sedentary
options for rhythm control?
- cardioversion
- immediate vs delayed
- elctrical vs pharmacological
- long-term medical rhythm control
other options, when drug treatment has failed?
- radiofrequency ablation of AV node
- maze procedure
- cardiac pacing
what should be given 4 weeks before electrical cardioversion & up to 12 months after?
amiodarone therapy
if AF>48h, what is preferred route of cardioversion?
electrical
by how much does anti-coagulation reduce risk of stroke in AF?
by 2/3
tool for assessing whether patient with AF needs to be started on anti-coagulation?
C- Congestive HF
Hypertension
A2- Age>75 ( score=2)
Diabetes
S2-Stroke or TIA previously (score=2)
Vascular disease
Age 65-74
Sex (female)
who does NICE recommend should start anti-coagulation?
in ALL pts with score 2 or more
- to be considered in men score >1
- women with a score of 1 due to gender = not an indication for treatment
assessment tool for assessing someone’s risk of bleeding whilst on anti-coagulation?
HT
Abnormal liver /renal function
Stroke
Bleeding
Labile INRs
Elderly
Drugs /alcohol
what anti-coagulants are given in AF?
- warfarin
- NOAC
if above contra-indicated: dual anti-platelet therapy
what anti-coagulants are given post stroke?
warfarin or direct thrombin/factor Xa inhibitor
