Atrial Fibrillation (Chronic) Flashcards
What is atrial fibrillation (AF)?
Atrial fibrillation (AF) is a supraventricular tachyarrhythmia.
Electrocardiographic characteristics include:
- Irregularly irregular R-R intervals (where atrioventricular conduction is not impaired)
- Absence of distinct repeating P waves
- Irregular atrial activations
What are the risk factors for AF?
- Coronary artery disease (CAD)
- Hyperthyroidism
- Valvular disease
- Hypertension
- Heart failure
- Diabetes
- Thyroid disorders
- COPD
- Obstructive sleep apnoea
- Advanced age
Damage to which heart valve is most commonly the cause of AF?
Mitral valve
Differentiate between paroxymal, persistent, long-standing and permanent AF
- Paroxysmal AF: recurrent AF that terminates spontaneously within 7 days.
- Persistent AF: lasts longer than 7 days.
- Long-standing persistent AF: continuous AF >1 year in duration.
- Permanent AF: refractory to cardioversion and sinus rhythm cannot be restored or maintained, such that AF is accepted as a final rhythm. A decision has been made by the patient and physician not to pursue restoration of sinus rhythm by any means, including catheter or surgical ablation.
What are the symptoms of AF?
- Palpitations
- Dizziness
- Sycope
- Fatigue
- Dyspnoea
What are the signs of AF?
- Tachycardia
- Irregularly irregular pulse
- Hypotension
- Elevated JVP
- Murmur or gallop rhythm
What investigations should be ordered for AF?
- ECG
- Serum urea and electrolytes
- Echocardiogram
- Cardiac biomarkers
- Thyroid function tests
- CXR
- Transthoracic echocardiogram
- Transoeophageal echocardiagram
What ECG changes are seen in AF?
- Absent P waves
- Presence of fibrillatory waves that vary in size, shape and timing
- Irregularly irregular QRS complexes
- Variable QRS heights
Why investigate serum urea and electrolytes (including serum magnesium)? And what may this show?
- Routine biochemistry should be done to assess for the presence of other co-morbid conditions, and to assess electrolyte and metabolic status.
- May be normal; may be abnormal with renal dysfunction.
Why investigate using echocardiogram? And what may this show?
- Echocardiogram is important to exclude important cardiac pathologies and risk factors for persistent AF such as valvular and pericardial disease, and cardiomyopathies.
- May have valvular regurgitation or stenosis, left ventricular or atrial enlargement, peak right ventricular pressure (pulmonary hypertension), left ventricular wall thickness and dysfunction.
Why investigate thyroid function? And what may this show?
- Thyrotoxicosis may present with AF.
- Suppressed thyroid-stimulating hormone (TSH) with elevated free T4 and/or T3.
What criteria scoring systems are used to assessment of AF? And why?
- CHAD-VASc: risk of thromboembolism
- HAS-BLED: risk of bleeding
Briefly describe the CHA2DS2-VASc scoring
CHA2DS2-VASc score
- 2 points:
- For history of stroke or transient ischaemic attack
- Age ≥75 years
- 1 point:
- Age 65-74 years
- History of hypertension
- Diabetes mellitus
- Recent cardiac failure
- Vascular disease (myocardial infarction, complex aortic plaque, peripheral arterial diseas)
- Female sex
What are the 3 elements in the management of AF?
- Rate control
- Rhythm control
- Prevention of thromboembolic events
When is direct current (DC) cardioversion indicated?
Used immediately if the patient is haemodynamically unstable with chest pain, shortness of breath, dizziness or sycope, hypotension and rapid heart rate.
