The heart consists of two large and two small muscular chambers. In atrial fibrillation the two small chambers of the heart called atria quiver instead of beating effectively. This leads to an irregular heart beat known as arrhythmia. As a consequence the blood is not pumped effectively round the body.
What causes Atrial Fibrillation to happen?
The causes are varied, but many cardiac disorders will lead to atrial fibrillation. It may be short-lived. Acute and chronic rheumatic heart disease is a common cause before the age of 50. Continuing problems with AF are associated with hypertension (high blood pressure) which is a common cause in later life, and sometimes thyrotoxicosis (thyroid disorder).
Who gets it?
The incidence of AF increases with age, it is rare in someone under twenty years and is slightly more common in men. It is a major cause of stroke, especially in the elderly. This is because an embolism (clot) can form in the left atrium of the heart and become detached and be carried in the blood stream to the brain. Subsequently it may lodge in one of the arteries in the brain causing the patient to lapse into a coma or suffer paralysis on one side. The risk of stroke varies with age and co-existence of heart disease.
What are the symptoms?
Most patients experience palpitations, but fatigue, laboured breathing (dyspnoea) and dizziness are also common together with an irregular heart beat.
How is it diagnosed?
The force and rate of heart beat are irregular; so the pulse rate at the wrist is counted and compared with the heart beat measured using a stethoscope. This is called the pulse deficit and may be as much as 20 beats. Patients should also have a two-dimensional echocardiogram. This examines the movement of the heart waves using an ultrasound beam.
What treatments are available?
The aims of treatment are to:
Try and return heart to normal
If not possible, control its rate of beating
If the heart has recently developed AF hospital doctors may try and return the heart to normal using drugs or electric shock (under anaesthetic).
If the heart keeps going back into AF or has been in AF a long time, then drugs are used to control the rate with the addition of Warfarin or Aspirin to prevent blood clots.