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
What are the symptoms of Atrial Fibrillation? Most patients with AF do not have any symptoms at all. If you have symptoms, they may be due to the heart beat being either too fast or too slow leading to: • Heart palpitations • Chest discomfort • Shortness of breath • Dizziness • Fainting spells Is Atrial Fibrillation dangerous? AF is never fatal on its own, however it may cause problems. If the heart beats too slowly, it will cause you to faint. If it beats too fast, it may weaken the heart, causing a shortness of breath. One of the most serious complications of AF is that clots tend to form easily in the heart chambers as it is beating irregularly. The clot can cause a stroke if it travels to the brain.
What are the tests needed? Apart from a medical examination and taking a history, your doctor will need to order a resting or 24 hour heart tracing, blood tests such as a thyroid profile and a heart scan (echocardiogram). A heart scan is to assess the size and strength of the heart chambers and condition of the heart valves.
What are the treatment options? Rhythm control Your doctor may aim to return your heart rate back to normal, and will advise you if it is necessary or possible based on your heart tests and medical condition. You may be given medications (Sotalol or Amiodarone). Another option is to undergo Cardioversion (giving the heart a small electric shock to reset the heart rhythm) or Ablation where keyhole techniques are used to channel the extra impulses away and return your heart rhythm to normal. Rate control Controlling the heart rate is the most common way to manage AF. The doctor will use medications (beta-blockers or calcium channel blockers) to control the heart rate.
Stroke prevention Treatment with blood thinners can prevent blood clots and reduce the risk of a stroke. There are two main types of blood thinning drugs - antiplatelets (Aspirin or Clopidogrel) or anticoagulants (Warfarin). Your doctor will help you choose the best option for you after a complete assessment of your heart.
Lifestyle changes There are some changes you can make to improve your condition. • Quit smoking. • Limit your alcohol and caffeine intake. • Control or prevent hypertension with a balanced diet and maintain a healthy weight. • Avoid cold remedies which may speed up your heart. • Do not stop your medications on your own accord. References http://www.mayoclinic.com http://www.americanheart.org
Yishun Health is a network of medical institutions and health facilities in the north of Singapore, under the National Healthcare Group. Admiralty Medical Centre • (65) 6807 8000 • www.admiraltymedicalcentre.com.sg Khoo Teck Puat Hospital • (65) 6555 8000 • www.ktph.com.sg Yishun Community Hospital • (65) 6807 8800 • www.yishuncommunityhospital.com.sg The information is correct at the time of printing and subject to revision without further notice.
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