Identification of Atrial Fibrillation

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia characterized by uncoordinated atrial activation. On the ECG fibrillatory (f) waves (rapid oscillations with variable amplitude, shape and timing) replace normal P waves. Ventricular response becomes irregular and rapid depending of the intrinsic electrophysiological properties of the AV node¹ and the balance between vagal and sympathetic tone¹.

The presence of an irregularly pulse is a clinical sign that can be quickly and reliably identified in any healthcare situation and, indicates AF with a high sensitivity and specificity (95% and 75%, respectively). If the irregularity last for more than 20 seconds the specificity reaches 98% ^2-4. Identification of AF can be done by using manual pulse palpation in those presenting with a variety of symptoms. It is desirable to check the blood pressure and pulse in all patients who present with breathlessness, dyspnea, palpitations, syncope, dizziness or chest discomfort. Furthermore, many patients presenting with an acute stroke are found to be in AF albeit asymptomatic with respect to non-neurologic complaints.

The finding of a sustained irregular wide QRS complex tachycardia may be suspicious of AF conducted with bundle brunch aberrancy or over an accessory pathway, and in patients with A-V sequential pacemakers can reflect an inadequate configuration with ventricular tracking of sensed atrial activity.