Atrial fibrillation

Atrial fibrillation (AF or AFib) is a cardiac arrhythmia (an abnormality of heart rate or rhythm) originating in the atria. Abnormal electrical impulses in the atria cause the ventricles to contract erratically. AF is the most common cardiac arrhythmia. If rapid, it may compromise blood flow and cause fainting, orthostatic hypotension (low blood pressure on standing up) or low blood pressure. In addition, it predisposes to thrombosis and embolism to the brain, being a prime risk factor for stroke.

Causes

AF is linked to several cardiac causes, but may occur in otherwise normal hearts. Known associations include:

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• Arterial hypertension
• Mitral valve disease(e.g. due to rheumatic heart disease or mitral valve prolapse)
• Heart surgery
• Coronary heart disease
• Excessive alcohol consumption ("binge drinking")
• Hyperthyroidism
• Hyperstimulation of the Vagus nerve, usually by having large meals ("binge eating")

In turn, untreated AF can cause further damage to the heart muscle. This weakened condition, termed chronotropic cardiomyopathy, is usually a result of relatively long term uncontrolled heart rate.

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