Atrial fibrillation Flashcards
How is AF classified?
- Paroxysmal AF = duration < 7 days w/ spontaneous resolution, or with intervention within 7 days of occurrence
- Persistent AF = AF that fails to self-terminate within 7 days
- Long persistent AF = AF > 1 year
- Permanent AF: Joint decision between patient and clinician not to pursue rhythm control treatment
- Non valvular AF: AF in the absence of rheumatic mitral stenosis, a mechanical or biprosthetic heart valve, or mitral valve repair
What are the complications of AF?
Embolism and stoke (presumably due to LA appendage clot) also includes AMI
Acute hospitalisation with onset of symptoms of palpitations
Anticoagulation, esp in older pt (>75YO)
CCF due to
- loss of AV synchronic
- loss of atrial kick
- rate related cardiomyopathy due to rapid ventricular response
Rate related atrial myopathy and dilatation
Chronic symptoms and reduced sense of well being
What are the causes of AF?
Most common causes
- Advanced age
- Hypertension
- Ischemic heart disease
- Valvular heart disease (Mitral and tricuspid)
- Heart Failure (from any cause)
- Thyrotoxicosis
- COPD
What is the presentation of AF?
Palpitations, Chest Pain, Dyspnoea
Heart Failure Symptoms (due to poor CO)
Thromboembolic events
- Stroke
- Acute Limb Ischaemia – 6Ps, sudden onset, no features of CLI
- Ischaemic Colitis – severe abdominal pain»_space; signs; +/- small amounts of LBGIT
What are the PE findings of AF?
Heart rate – irregularly irregular pulse
If present 🡪 assess for thromboembolic complications of stroke, ALI etc
What are the investigations required for AF
ECG – loss of p waves, narrow QRS tachycardia, irregular
CXR – for cardiomegaly, for underlying Heart disease that may ppt AF
FBC – for infection
Trop I
Electrolytes – may ppt arrhythmias
TFT
Trans-Esophageal Echocardiogram
- For clots (if considering cardioversion)
- Or TTE to assess for valvular / non valvular aetiology (eg; CM)
24hr Holter if paroxysmal AF
What is the management of stable AF patients?
Rate control
- Achieved through drugs that block the AV node
(increase AV nodal
- Reasonable strategy in elderly patients with minimal symptoms
- 1 st line: beta blockers, non DHP calcium channel blockers
- Betablockers: preferred in patients with HFrEF , HTN, IHD
- Calcium channel blockers: useful in severe COPD/asthma
- Digoxin: usually 2 nd line, can be used in HF
- AV nodal blocking agents are contraindicated in patients with WPW/ preexcited AF e.g betablockers, CCB, amiodarone
- Generally aim for HR of 70 90bpm at rest with acceptable exercise tolerance, if patients are asymptomatic
- A lenient rate control strategy (resting HR <110bpm) is reasonable as long as patients are asymptomatic and LV
function is preserved
Rhythm Control
- Unnecessary for most patients
- Indicated only if symptomatic AF
- Before cardioversion: so a TEE TRO thrombus b/c thrombus most likely located on the LA Appendage, positioned posteriorly within the heart 🡪 best visualised by TWW
- Medications recommended: Class IA, IC and III antiarrhythmics (Vaughan Williams classification)
If refractory to rhythm control
- Focal Ablation – only if trigger is located within pul veins or part of RA
- Ablation of AV node and implant pacemaker
- Surgical
Anticoagulation (to minimize risk of thromboembolism)
- Selection of anticoagulation therapy should be based on the risk of thromboembolism irrespective of whether the AF pattern is paroxysmal, persistent, or permanent
- NOACs are recommended over warfarin in eligible patients (except in
valvular AF and prosthetic mechincal heart valves)
- Warfarin: w/ initial overlap w/ LMWH for 7 days
- There is no need for bridging therapy unless acute DVT / PE
- In the above cases, only Dabigatran and Warfarin will require LMWH bridging therapy
Cardiovascular and comorbidity optimisation
What is the CHA2DS2VAS Score for stroke risk?
- Congestive heart failure/ LV dysfunction [1]
- Hypertension [1]
- Age > 75 years [2]
- Diabetes mellitus [1]
- Stroke / TIA/ TE [2]
- Vascular disease (prior MI, PAD, or aortic plaque) [1]
- Age 65-74 years [1]
- Sex category (female) [1]
Selection of anticoagulation therapy should be based on the risk of thromboembolism irrespective of whether the AF pattern is paroxysmal, persistent, or permanent
What is the HASBLED Score for bleeding risk?
- Uncontrolled hypertension
- Abnormal liver or renal function
- Stroke
- Bleeding
- Labile INR
- Elderly (age >65)
- Drugs or alcohol
What are the INR targets on warfarin? How do you reverse elevated INR?
INR Targets on Warfarin
- Target INR at 2.5 (2.0 – 3.0) in general
- If prosthetic heart valve replacement, aim for 3 (2.5-3.5)
- In elderly patients >75 years of age, or in those deemed to be at higher bleeding risk, a lower INR target of 1.6 – 2.5 may be chosen instead, balancing the risks and benefits of anticoagulation
Elevated INR >3 on Warfarin
- If INR < 6 + no bleeds – pause warfarin for 3 days or so
- If INR > 6 + no bleeds – PO Vit K 1-5mg (works in 6-8 hours)
- If INR Major Bleed – REVERSE WARFARIN
• STOP WARFARIN
• 4 Factor Prothrombin Complex Concentrate (PCC; contains factors 2, 7, 9, 10)
• AND VITAMIN K 10mg Infusion on top of PCC
• Major bleed is usually Intracranial haemorrhage or BGIT
What are the pros of warfarin?
- Cheap (cents/day)
- Measurable (INR)
- Easily Reversible (PCC, Vit K)
- Can be used in renal insufficiency
- Not C/I in renal insufficiency
- Effective: many yrs of exp
What are the C/Is for warfarin?
Warfarin contraindications
- Active hemorrhage
- Pregnancy especially if dose of warfarin is >5mg in the 1 st trimester, or before delivery
- Severe uncontrolled Hypertension
- Recent trauma
- Neurosurgical procedures
- Aneurysms, blood dyscrasias a/w hemorrhage or thrombocytopenia
Relative contraindications
- Risk of hemorrhage (HASBLED score)
- Non compliance
- Frequent falls >3 times a year
What are the pros of NOACs?
- No monitoring needed
- Lower bleeding risk
- No special diet, less DDI
- ORAL! Ease
What are the cons of NOACs?
- Expensive (a few $ a day)
- Difficult to reverse – no antidote readily available
(only PCC – prothrombin complex concentrate) - Renal dosing (must take note in renal insuff / C/I in RF)
- Contraindicated in mechanical valves
What are the pros of aspirin?
- Cheap
- Safe
- Lower bleeding risk
- CVS benefit
