Atrial Fibrillation

Question 1

What is Atrial Fibrillation?

Answer 1

• Irregular and frequently fast heart beat (arrhythmia)= cause blood clots

Question 2

Aetiology

Answer 2

• MI, atherosclerosis, CHD, cardiomyopathy
• hypertension, pulmonary disease, sleep apnea
• hyperthyroidism, asthma/COPD, previous heart surgery

Question 3

Pathophysiology

Answer 3

• Signals of heart disorganised (causes below):
   Tachycardia: heart rate 100-175bpm—normal HR= 60-100bpm
   Irregular ventricular contraction
   Increased risk of stroke= blood clot in atria=travel to brain=ischaemic stroke
   If not controlled then HF

Question 4

Risk factors

Answer 4

-Age, heart disease, hypertension, thyroid disease
- obesity, family history, alcohol use, diabetes, metabolic disorders
- chronic kidney disease, lung disease

Question 5

Signs/Symptoms

Answer 5

• Chest pain, palpitation, shortness of breath, dizziness, tiredness

Question 6

Investigations

Answer 6

• 12 Lead ECG
• Blood test
• 24 hr ECG
• Echocardiogram
• CXR: look at hear size/rule out HF

Question 7

Diagnosis

Answer 7

• Physical examination: irregular pulse rate/history

Question 8

Management

Answer 8

• Anticoagulation main priority
• Treatment spilt into rate and rhythm control

Question 9

Rate control

Answer 9

• Beta blocker: bisoprolol/atenolol
• Calcium channel blocker: diltiazem/verapamil
• Digoxin: can be used as 2nd line, pt maximum dose of beta blocker/calcium channel blocker, only used for pt w/ sedentary lifestyle

Question 10

Rhythm control

Answer 10

• Pt has AF lasts less than 48hrs, this is best course
• Cardioversion required urgently if pt acutely unwell
   Pharmacological cardioversion: flecainide/amiodarone
   Electrical cardioversion: heart shocked into sinus rhytm, sedation/general anaesthesia, controlled delivery of shocks from cardiac defibrillator machine (restore sinus rhythm)
• Long term rhythm control: beta blocker (1st lne)—dronedarone (2nd line)—amiodarone (HF pts)

Question 11

Paroxysmal Atrial Fibrillation

Answer 11

• Intermittent AF that lasts no more than 48 hrs
• CHADSCASc sore, pt should continue taking anticoagulants.
• Pt will be told to take meds when experiencing symptoms of atrial filbrillation==BUT SHOULD NOT ANY UNDERLYING HEART DISEASE,
• Flecanide: standard treatment

Question 12

CHAD2DSVA5c

Answer 12

• Pt with AF-likely to get blood clot
• Anticoagulation has to be considered to reduce risk of TIA and stroke
• Risk of stroke in AF can be looked into using CHAD2DS2VASC algorithm
• Help determine if anticoagulation required to give to pt

Question 13

CHA2DS2VASc score

Answer 13

• Decision for anticoagulant therapy can be made using score table
• patient should be given option of direct acting oral anticoagulant (DOAC) or vitamin K antagonist e.g. warfarin
• DOAC/Novel anticoagulants (NOACs)
   Apixaban, edoxaban, rivaroxabanm dabigatran: treatment for AF
   Inhibit clotting cascade of factor Xa=stops thrombus formation

Question 14

Warfarin

Answer 14

• vitamin K antagonist
  -prolongs prothrombin time (times it takes for blood to clot)
• Measure international normalised ratio(INR) = assess how anticoagulated patient is by warfarin
• INR 1 = normal prothrombin time
• INR 2 = prothrombin time twice of normal healthy adult= takes twice as long to form blood clot
• Target INR for AF = 2-3

Question 15

Bleeding risk

Answer 15

• calculated using HAS=BLED score
• H: hypertension = bp>160mmHg
• A: abnormal renal and liver function = chronic dialysis, renal transplant, creatinine >2.3
• S: Stroke
• B: Bleeding history
• L: Labile INRs (whilst on warfarin)
• E: elderly=65yr+
• D: drugs/alcohol