Atrial fibrillation

Question 1

Is AF more prevalent in women or men?

Answer 1

More prevalent in men.

Question 2

Is AF mortality more prevalent in women or men?

Answer 2

Mortality is higher in women.

Question 3

What is the pathophysiology of AF?

Answer 3

· AF is usually associated with anatomically and histologically abnormal atria as a result of underlying heart disease.
· Atrial dilatation with fibrosis and inflammation causes a difference in refractory periods within the atrial tissue.
· This promotes electrical re-entry that results in AF.
· New-onset AF causes an increase in coronary flow. But this isn’t adequate to compensate for the increased myocardial oxygen demand that occurs as a result of irregularity in the ventricular rhythm.

Question 4

The prognosis depends on what 4 factors?

Answer 4

1. Precipitating event.
2. Underlying cardiac status.
3. Risk of thromboembolism.
4. Whether the AF is paroxysmal, persistent or permanent.

Question 5

There is increased mortality with the presence of AF in the setting of which condition?

Answer 5

MI.

Question 6

What is the aetiology of AF?

Answer 6

· CAD, HTN, heart failure, valvular disease, diabetes, thyroid disorders, COPD, OSA and advanced age are risk factors for the development of new-onset AF.
· However, AF can occur in the absence of underlying cardiac or non-cardiac disease, such as the result of heavy alcohol intake.

Question 7

What are the common risk factors for AF?

Answer 7

· Increasing age. 
· Diabetes mellitus. 
· HTN. 
· Congestive heart failure.
· Valvular heart disease. 
· CAD. 
· Other atrial arrhythmias. 
· Cardiac or thoracic surgery - common post-op complication.
· Hyperthyroidism - untreated thyrotoxicosis can develop AF.

Question 8

What are the common signs and symptoms?

Answer 8

· Palpitations. 
· Hypotension. 
· Elevated JVP. 
· Added heart sounds. 
· Dizziness.
· Irregularly irregular pulse rate.

Question 9

What investigations would you request if you suspected a patient had AF?

Answer 9

· ECG.
· Electrolytes.
· Cardiac biomarkers (for new-onset). 
· TFT's: suppressed TSH if hyperthyroidism.
· CXR. 
Transthoracic ECHO.

Question 10

What would an ECG show?

Answer 10

· Absent P waves.
· Fibrillatory waves that vary in size, shape and timing.
· Irregularly irregular QRS complexes.

Question 11

Suggest some differential diagnoses.

Answer 11

· Atrial flutter. This will show saw-tooth appearance on inferior leads. QRS complexes are regularly irregular.
· Wolf-Parkinson-White. Usually younger patients. Shortened PR interval and delta wave on QRS complex.
· Atrial tachycardia. More common in patients with severe COPD.

Question 12

What is AF treatment based on?

Answer 12

· Haemodynamically stable or unstable.
· With or without heart failure.
· With or without left atrial thrombus.
· Symptom onset <48hrs of >48hrs.

Question 13

What are the current treatment options?

Answer 13

· If haemodynamically unstable - Direct current (DC) cardioversion.
· Rate control with beta-blockers/CCB’s/digoxin/amiodarone.
· Anticoagulation.
· Electrical or pharmacological cardioversion following 3-4 weeks of anticoagulation.
· Heparin.
· Observation.

Question 14

What drugs are typically given to treat AF?

Answer 14

Anticoagulation or antiplatelet therapy: warfarin + control rate of heartbeat: bisoprolol/propranolol (1st beta blcoker), digoxin/dilitazem (2nd - calcium channel blocker).

Question 15

List the complications that can occur.

Answer 15

· Acute stroke.
· MI.
· Congestive heart failure..