ECG: 09. Atrial fibrillation - with Video

Atrial fibrillation is one of the commonest arrhythmias seen in a medical ward, probably second only to ectopics.

Here is how it looks like on a cardiac monitor:


In atrial fibrillation,

• there is an irregularly irregular ventricular rhythm. Sometimes it may appear regular on a brief look, but on close inspection it will be clearly irregular.
• P waves will be absent (replaced by "f" waves - f for fibrillation, as opposed to "F" waves in atrial flutter).
• Generally there a rapid ventricular rate (unless the patient is being treated with rate-control medications like beta blockers or digoxin).

Thromboembolic complications are frequent (thrombus is formed in the left atrium commonly due to stasis). Hence most patients are prescribed anticoagulants.

Dilemma in therapy:
Rate-control or Rhythm control?
In fact, this is the first question to be answered in the therapy of atrial fibrillation. Should we control the rate or the rhythm?
In acute onset atrial fibrillation with no structural cardiac pathology, rhythm control may be preferred. However, most patients have a structural pathology like rheumatic heart disease or significantly dilated left (or right) atrium, making rhythm control almost impossible.
Therefore chronic atrial fibrillation and AF with structural cardiac pathology are treated with 'rate-control'.