Atrial Fibrillation Atrial Fibrillation (AF) A heart beat normally starts at the sinus node in the right atrium. The impulse travels down the heart (Diagram A) at regular intervals. In AF, multiple extra impulses arise from the atrial walls and compete to travel down the heart as well (Diagram B) causing a disorganised heartbeat. What causes Atrial Fibrillation? AF usually occurs when the heart chamber called the atrium enlarges or is damaged and generates multiple impulses on its own. This is associated with many factors including hypertension, heart valve disease, acute or chronic lung disease, heart failure and coronary heart disease. In some cases, no obvious cause can be found and this is called “Lone AF”.
Diagram A Normal Conduction
Diagram B Atrial Fibrillation
Normal Electrical Signals SA Node
Normal Sinus Rhythm
Disorganised Electrical Signals SA Node
Atrial Fibrillation