Atrial Fibrillation Flashcards
Criteria for AFib
- The surface ECG shows “absolutely” irregular RR intervals (AF is therefore sometimes known as arrhythmia absoluta), i.e. RR intervals that do not follow a repetitive pattern.
- There are no distinct P waves on the surface ECG. Some apparently regular atrial electrical activity may be seen in some ECG leads, most often in lead V1.
- The atrial cycle length (when visible), i.e. the interval between two atrial activations, is usually variable and <200 ms (300 bpm).
Conditions predisposing to, or encouraging progession of AF
Types of AF
Every patient who presents with AF for the first time is considered a patient with first diagnosied AF, irrespective of the duration of the arrhythmia or the presence and severeity of AF-related symptoms.
Paroxysmal AF is self-terminating, usually within 48 hours. Although AF paroxysms may continue up to 7 days, the 48 hour time point is clinically important - after this the likelihood of spontaneous conversion is low and anticoagulation must be considered.
Persistent AF is present when an AF episode lasts longer than 7 days.
Long-standing persistent AF has lasted for >1 year when it is decided to adopt a rhythm control strategy.
Permanent AF is said to exist when the presence of the arrhythmia is accepted by the patient (and physician).
Classification of AF-related symptoms (EHRA score)
CHA2DS2-VASc
scoring system for non-valvular
atrial fibrillation
How to choose appropriate antithrombotic therapy?
DOACs - 2 types
MoA of DOACs
When oral anticoagulation is required, either warfarin (dose
adjusted to maintain an INR between 2.0 and 3.0) or one of the direct
oral anticoagulants (the DOACs) can be used. These latter agents fall
into two classes: direct thrombin inhibitors (e.g. dabigatran) and oral
direct factor Xa inhibitors (e.g. rivaroxaban and apixaban).
DOACs specifically block a single step in the coagulation cascade, in contrast to warfarin, which blocks several vitamin K-dependent
factors (II, VII, IX and X).
In comparison with warfarin, the DOACs have a rapid onset of action, shorter half-life and fewer food and drug interactions, and do not require INR testing. Trial data have shown them to be equally effective as, and maybe safer than, warfarin.
Antiplatelet agents should not be used to reduce stroke risk.
Percutaneous left atrial appendage occlusion (LAAO) may be offered where anticoagulation is contraindicated or not tolerated.
HAS-BLED
score for bleeding risk on oral
anticoagulation in atrial fibrillation
Anticoagulation in Atrial Fibrillation
Valvular AF…
If the patients presents with Valvular AF, they shall be treated with Vitamin K antagonists (Warfarin, Acenocumarol).
Left atrial appendage occlusion/closure (LAAO/LAAC)
Reduce the risk of…
What is LAAO/LAAC?
Procedure
Picture:
The left atrial appendage is the windsock-like structure shown to originate from the left atrium (3 o’clock).
https://en.wikipedia.org/wiki/Left_atrial_appendage_occlusion
Left atrial appendage occlusion (LAAO), also referred to as Left atrial appendage closure (LAAC) is a treatment strategy to reduce the risk of left atrial appendage blood clots from entering the bloodstream and causing a stroke in patients with non-valvular atrial fibrillation (AF).
In non-valvular AF, over 90% of stroke-causing clots that come from the heart are formed in the left atrial appendage. The most common treatment for AF stroke risk is treatment with blood-thinning medications, also called oral anticoagulants, which reduce the chance for blood clots to form. These medications (which include warfarin, and other newer approved blood thinners) are very effective in lowering the risk of stroke in AF patients. Most patients can safely take these medications for years (and even decades) without serious side effects.
Left atrial appendage closure is an implant-based alternative to blood thinners. Like blood thinning medications, an LAAC implant does not cure AF. A stroke can be due to factors not related to a clot traveling to the brain from the left atrium. Other causes of stroke can include high blood pressure and narrowing of the blood vessels to the brain. An LAAC implant will not prevent these other causes of stroke.
Powerpoint (attached picture from Google [Hopkin’s Medicine]):
It is inserted via femoral vein, right atrium and transseptally into LAA where after expanding it occludes exactly the orifice of LAA.
Cardioversion of Atrial Fibrillation (Pharmacological focus)
Ibutilide should not be given when…
Vernakalant should not be given in…
a: Ibutilide should not be given when significant left ventricular hypertrophy (>1.4 cm) is present
b: Vernakalant should not be given in moderate or severe heart failure, aortic stenosis, acute coronary syndrome or hypotension. Caution in mild heart failure.
c: “Pill-in-the-pocket” technique - preliminary assessment in a medically safe environment and then used by the patient in the ambulatory setting.
Cardioversion of Atrial Fibrillation (Route focused)
SR: Sinus Rhythm
AF: Atrial Fibrillation
OAC: Oral Anticoagulant
TOE: Transoesophageal Echocardiography
LAA: Left Atrial Appendage
Drugs for rate control (Atrial Fibrillation)
Left atrial ablation / Atrial fibrillation ablation
https://www.mayoclinic.org/tests-procedures/atrial-fibrillation-ablation/about/pac-20384969
Atrial fibrillation ablation is a treatment for an irregular and chaotic heartbeat called atrial fibrillation (A-fib). It uses heat or cold energy to create tiny scars in your heart to block the abnormal electrical signals and restore a normal heartbeat.
Atrial fibrillation ablation may be used if medications or other treatments don’t work. Sometimes it’s the first treatment for certain patients.
Atrial fibrillation ablation is most often done using thin, flexible tubes called catheters inserted through the veins or arteries to the heart. Less commonly, ablation is performed during cardiac surgery.
