Atrial Fibrillation


Atrial rate usually between 400-650/bpm.

P wave

Not present; wavy baseline is seen instead.


Usually normal, a wide QRS may indicate conduction by accessory pathway.


Variable AV conduction; if untreated the ventricular response is usually rapid.


Irregularly irregular with abscence of P waves. (This is the hallmark of this dysrhythmia).


Palpitations, chest pain, dyspnea, fatigue, lightheadedness, or syncope.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. AF increases the risk hemodynamic impairment and thromboembolic events. It may occur paroxysmally, but it often becomes chronic. Signs of acute atrial fibrillation are: hypotension, myocardial ischemia, decreased perfusion of vital organs and acute congestive heart failure (CHF). Chronic atrial fibrillation increases the risk of atrial mural thrombus and embolus. Some conditions associated with atrial fibrillation are: mitral stenosis, lung disease, heart disease, sepsis, hyperthyroidism and cardiac surgery.


Treatment is directed at rate control, antithrombotic therapy and correction of rhythm. Slowing the ventricular rate by increasing the AV node refractory period. Digoxin, beta-adrenergic blockers, calcium channel blockers may be used to reduce the rate of AV conduction to 80-100 beats/minute. Patients with chest pain, ischemia, congestive heart failure, mitral stenosis or hypotension may require intravenous verapamil, digoxin or a combination to quickly control the ventricular rate. In appropriate patients cardioversion either chemical, electrical or a combination may be required to convert this arrhythmia to normal sinus rhythm.

Instant Feedback:

The hallmark sign of atrial fibrillation is:

An abscence of P waves and an irregulary irregular ventricular rate
A sawtooth pattern

Please visit Virtual Hospital's site on cardiac arrhythmias.