Atrial Fibrillation Flashcards
What is the most common sustained cardiac arrhythmia?
AF
List symptoms of AF?
- asymptomatic
- palpitations
- chest pain
- syncope (due to rapid/slow HR)
- SOB
- may present with stroke/embolism
Why do patients get SOB in AF?
If in AF, you lose atrial kick to help fill ventricles so you get a decreased cardiac output.
Describe the pulse in AF?
Irregularly irregular.
List and describe the 3 types of AF?
Paroxysmal: Intermittent - episodes start and stop. They can last seconds - 24h.
Persistant: Wont stop alone, requires intervention to stop.
Permanent: Intervention wont stop it.
Describe the AF ECG?
- variable rate
- irregular narrow QRS
- no P waves
Describe atrial contraction in AF?
Atria don’t contract together. Different cells contract at different rates.
Atria ‘wobble’ rather than contracting.
How does atrial fluter differ from AF physiologically?
Atria contract in a coordinated way but very fast.
Why do the atria contract faster than the ventricles in atrial flutter?
Because the atria are contract so fast that not impulses get through due to variable degrees of AV block.
Describe atrial flutter on ECG?
- Variable rate
- Regular, narrow QRS
- ‘Sawtooth’ atrial activity at around 300bpm.
Who is more likely to get AF?
Older people
Males
List some conditions predisposing to AF?
Hypertension HF Valvular HD Thyroid dysfunction (particularly hyperthyroid) Cardiomyopathies Diabetes
List GGC’s objectives of AF treatment?
- prevention of stroke
- symptom relief
- management of CV disease
- rate contol
- +/- correction of rhythm disturbance.
How would you investigate suspected AF?
- ECG to confirm arrhythmia.
- Echocardigram
- Thyroid function tests
- Liver function tests
What is the target HR in AF patients?
<100bpm
if still symptomatic at 100 then aim for 80 bpm.
What drugs are used to ‘rate control’ in AF?
Either a B-blocker (bisoprolol)
OR rate-limiting Calcium channel antagonist (verapamil).
List MAJOR risk factors for stroke and thrombo-embolism.
How many points are these worth?
- previous stroke
- TIA or systemic embolism
- age >75 years.
2 points
List Clinically-relevant NON-MAJOR risk factors for stroke or thrombo-embolism?
How many points are these worth?
- Chronic heart failure or severe LV dysfunction.
- Hypertension
- Diabetes
- Aged 65-74
- Female
- Vascular disease.
1 point.
Stroke risk is calculated by assigning points for major and clinically relevant non-major risk factors. What is this score out of? aka Max score.
9
How do we reduce stroke in patients at high risk?
Used to give warfarin (but needed INR monitoring).
Now use new oral anti-coagulation
- Dabigatran (thrombin inhibitor)
- Rivaroxiban/Apixaban/Edoxaban (Factor Xa inhibitor)
What patients with AF would get reffered for specialist treatment?
- Symptomatic patients despite rate control.
- Patients <60 yo.
- Inadequate rate control despite B-blocker/Ca antagonist + digoxin.
- Structural heart disease seen on echo e.g. valve disease or LV dysfunction.
- AF and co-existing HF.
When is ‘rhythm control’ used in AF?
In younger patients and those with ongoing symptoms despite rate control.
What options are available for rhythm control?
Direct current cardioversion
Anti-arrhythmic drugs
Catheter ablation
What anti-arrhythmic drug options?
Class 1: Na+ channel blockers.
- Flecainide
- Propafenone
Class 3: K+ channel blockers (prolong AP duration and QT interval)
- Sotalol
Multi-channel Blockers
- Dronedarone
Where else other than the atria can abnormal beats come from?
Sometimes abnormal beats come from the pulmonary vein.
Due to sleeves of myocardium going from LA to the pulmonary vein.
Describe the process of catheter ablation?
Radiofrequency ‘point-to-point’ ablation.
Cryo-balloon ablation. administering liquid nitrogen around the pulmonary veins.
