Atrial Fibrillation

Atrial fibrillation or AF is caused by very fast, irregular electrical impulses (firing about 300 to 500 times a minute). These impulses may start from several places in the heart’s upper chambers or atria. The most common place is in one or more of the four blood vessels – the pulmonary veins – that enter the left upper chamber or left atrium from the lungs. The fast impulse rate causes the atria to quiver or beat ineffectively.

During AF, the heart rate can be slow, normal or as fast as 150 to 200 beats per minute. The rhythm usually is irregular.

Normally, AF is not life-threatening. But it can increase your risk of stroke. AF can be one of the following:

  • Paroxysmal (comes and goes on its own)
  • Persistent (requiring treatment to convert to the normal rhythm)
  • Permanent (never returning to the normal rhythm)

Patient education – video links

Atrial Fibrillation (HRS) 

Patient education – narrative information

Atrial Fibrillation (HRS) 
Atrial Fibrillation Center (ACC) 
Atrial Fibrillation (ACC)
Atrial Fibrillation (NHLBI)


Atrial Fibrillation