Atrial Fib/Anticoagulants Flashcards
What are the symptoms of atrial fibrillation?
- Irregularly irregular pulse
- Chest pain
- Breathlessness
- Syncope
- Oedema
- Palps
- Dizziness
- Fatigue
What are the cardiac causes of atrial fib?
most common at top
- Rheumatic heart disease
- Hypertension
- IHD
- Cardiomyopathy
- Sick sinus syndrome
What are the non cardiac causes of atrial fib?
most common at top
- Alcohol excess
- Acute infection
- PE
- Lung cancer
- Pleural effusion
- Thyrotoxicosis
How is AF classified?
Acute - first episode, lasting over 30s
Paroxysmal - recurrent, self-limiting episodes within 7 days
Persistent - recurrent episodes over 7 days, need cardioversion
Permanent - ongoing (>1yr) despite treatment
What is the pathophysiology of AF?
Impulses from the SAN are overhwlemed by disorganised electrical impulses. This is perpetuated by abnormal fibrous atrial tissue.
The result is a loss of atrial contraction and a rapid, irregular ventricular rate.
How is AF diagnosed?
ECG - wandering baseline, absent p waves, irregularly irregular
What investigations should be done in someone with suspected AF?
ECG, echo, FBC, TFTs
What are the 2 risk assessment scores in AF?
Bleeding risk - HASBLED
Stroke risk - CHA2DS2VAS
Which variables does the CHA2DS2VAS score take into account?
Coronary heart disease 1 Hypertension 1 Age >75 2 Diabetes 1 Stroke/TIA 2 Vascular Age 65-74 1 Sex (female) 1
Which variables does the HASBLED score take into account?
Hypertension 1 Abnormal renal/liver function 1 each Stroke/TIA 1 Bleeding 1 Labile TIA 1 Elderly (age>65) 1 Drugs/alcohol 1 each
If a pt with AF has unstable cardiovascular status how should they be managed?
- Rhythm control
- Thromboprophylaxis with heparin
If a pt with AF has stable cardiovascular status how should they be managed?
- Rate control
- Symptom assessment for rhythm control
- Stroke awareness and prevent
In which cases should rate control be offered?
Offer to everyone EXCEPT:
- reversible cause of AF
- heart failure from AF
- new-onset AF
- if they would benefit more from rhythm
What rate control options are available?
1st line - B blocker (atenolol, metoprolol) or CCB (dilitiazem, verapamil)
2nd line - Digoxin
When should digoxin be used?
Elderly, sedentary
What are the side effects of digoxin?
- Dizziness
- Yellow vision
- Heart block
- Thrombocytopenia
In which cases should rhythm control be offered?
Those whose symptoms continue after rate control or are unstable.
If symptoms have been ongoing for 48h, use electrical cardioversion (BUT ANTICOAGULATE BEFORE TO MINIMISE STROK RISK)
What pharmacological rhythm control options are available?
Class III - amiodarone
Class IV - flecanide, propafenone
Beta blockers
What are the benefits of amiodarone over flecanide?
Reduced risk of hypertension and heart failure. Better for use in anyone with heart disease, be it structural or ischaemic
What are the side effects of amiodarone?
Photosensitivity
Thyroid dysfunction
Pulmonary fibrosis
These SEs stay for a while after drug discontinutation
What are the benefits of flecanide over amiodarone?
More effective if given within 12h
Effectivity levels out at 24h
What should you give 6 wks before and a year after electrical cardioversion?
Amiodarone - maintains sinus rhythm
What should be used for long term rhythm control?
1st line - atenolol
2nd line - dronedarone (safer form of amiodarone)
How should acute AF be managed?
a) haemodynamically stable
b) unstable
a) <48h - rhythm or rate, >48h - rate
b) electrical cardioversion
In which cases should you offer anticoagulation to patients with AF?
Use CHA2DS2VAS score - offer if 2 or above.
Do not offer if <65 with no RF
What are the options for AF anticoagulation?
Aim for INR 2-3
Warfarin
Direct thrombin inhibitors - dabigatran
Factor xa inhibitors - apixaban, rivaroxaban
What are the advantages and disadvantages of warfarin ?
Adv - cheaper, antidote available (vit K)
Disadv - narrow therapeutic index, interactions, monitoring
What are the advantages and disadvantages of NOACs?
Adv - no monitoring
Disadv - expensive, no antidote, GI bleeding
Name some inducers of warfarin
Alcohol, rifampicin, st johns wort, phenytoin, carbamazepine
Name some inhibitors of warfarin
Amiodarone, cranberry juice, erythromycin, ciprofloxacin, simvastatin, SSRI, tramadol
What should be given in a warfarin overdose?
Mild - vitamin K
Severe - beriplex (prothrombin complex concentrate)
What are the contraindications for warfarin?
Peptic ulcer, bleeding disorder, HTN, pregnancy
What are the complications of AF?
- Stroke/TIA
- Thromboembolism
- Rate related cardiomyopathy - inability of heart to empty and fill properly
- Pulmonary oedema - fluid backs up in the lungs
How should you manage a moderately high INR without bleeding?
Omit a dose of warfarin
How should you manage a significantly high INR without bleeding?
Omit a dose of warfarin and prescribe oral vitK
How should you manage a significantly high INR with bleeding>
Oral/IV vitK and beriplex admin (containts 2, 7, 9, 10)
If beriplex isn’t available, give FFP
