Atrial Fibrillation Flashcards
What is acute/first detected AF?
AF with the onset within 48 hours
What is paroxysmal AF?
AF that is self-terminating within 7 days, usually within 48 hours
What is recurrent AF?
AF occurring >2 episodes; Paroxysmal or persistent AF
What is persistent AF?
AF that is not self-terminating, lasting more than 7 days
What is permanent AF?
AF that lasts for more than a year
How common is AF?
1% prevalence in population
18% in >65
Prevalence increases with age
Who does AF affect?
1/3 in patients after coronary bypass surgery and >1/2 undergoing valvular surgery
What is the aetiology of AF?
- Disorganised, rapid and irregular activation of the atria (300-600 bpm)
- Irregular ventricular response as an effect
- Irregularly irregular heartbeat
What are the causes of AF? (Heart conditions)
- Generally increased intra-cardial pressure
- atherosclerosis
- Myocardial Infarction
- congestive heart failure
- left ventricular hypertrophy
- valvular heart disease (mitral regurgitation, aortic stenosis)
What are the causes of AF?
- pulmonary embolism
- pneumonia
- hypertension
- hyperthyroidism
- post operative (hypokalaemia, hypomagnesia)
- alcohol, caffeine
- sarcoidosis
- obesity
- idiopathic/ ‘lone’ AF
What are the risk factors of AF?
- age
- diabetes
- obesity
- HTN
- smoking, caffeine, alcohol
- metabolic syndrome
What are the symptoms of AF?
- asymptomatic (in up to 20% of cases)
- chest pain
- palpitation
- dyspnoea
- faintness (actual syncope is rare)
What are the signs of AF on examination?
- irregularly irregular pulse
- 1st heart sound of variable intensity/loudness
- apical pulse rate is greater than radial pulse rate
- signs of left ventricular failure (pink frothy sputum, tachypnoea, orthopnoea, rapid pulse)
What are the differential diagnosis of AF?
- Atrial flutter (saw-toothed ECG; may be irregular or regular, usually tachycardic)
- Supraventricular tachyarrhythmia
- Wolff-Parkinson-White syndrome
- Ventricular tachycardia
What are the investigations to confirm the diagnosis of AF?
-ECG
-Bloods:
..TFTs (thyrotoxicosis can precipitate event),
..Us+Es (look for electrolyte disturbances/renal failure- abnormal serum potassium levels can potentiate arrhythmia),
..cardiac enzymes (investigate MI as primary or secondary event)
-Echocardiogram: for left atrial enlargement, mitral valve disease, structural abnormalities
What would an ECG finding of an AF look like?
- no P wave
- narrow QRS complex
- irregular baseline
- irregularly irregular rhythm
What are the treatments of AF when caused by acute precipitating event?
Underlying cause should be treated:
- alcohol toxicity
- chest infection
- hyperthyroidism
What is the treatment for AF in haemodynamically unstable patients?
1) Immediate heparinisation -> administer heparin
2) Attempt cardioversion -> synchronised DC shock
3) If cardioversion fails/AF recur->IV amiodarone
- then attempt another cardioversion
What is the treatment for AF in stable patients?
Two strategies available:
1) Rate control
2) Rhythm control
What is the principle of rate control treatment in AF?
-To reduce heart rate at rest and exercise
-However, pts remains in AF
>Beta-blockers: propanolol, atenolol, bisoprolol
>Calcium antagonist: verapamil/diltiazem
>Digoxin used only in sedentary people
What is the principle of rhythm control treatment in AF?
1) Electrical DC cardioversion + B-blockers to suppress arrhythmias
2) Pharmacological cardioversion: oral Flecainide
What is one of the greatest risk for patients with AF?
Thromboembolism.
Anticoagulation may be with apixaban, dabigatran, rivaroxaban or a vitamin K antagonist (eg. warfarin).
