Types of Atrial Fibrillation:

Paroxysmal: This is AF which occurs intermittently. Symptoms may come and go, only lasting for a few minutes to hours before stopping spontaneously.

This is AF which occurs intermittently. Symptoms may come and go, only lasting for a few minutes to hours before stopping spontaneously. Persistent: Your heart rhythm doesn’t go back to normal on its own that’s why an electrical shock is used to restore it.

Your heart rhythm doesn’t go back to normal on its own that’s why an electrical shock is used to restore it. Long-standing persistent: With its definition as persistent, it is continuous and may last longer than a year.

With its definition as persistent, it is continuous and may last longer than a year. Permanent: With this type of AF, your abnormal heart rhythm cannot be restored and the focus of treatment will be to keep your heart rate under good control with medications.

2. Causes Of Atrial Fibrillation

Because AF produces an irregular and fast heart rhythm, your pulse rate in AF may typically range from 100 to 175 beats per minute. (Our normal heart rate is 60 to 100 beats per minute.)

Here are some causes of Atrial fibrillation:

Abnormal heart valves

Coronary Artery Disease (CAD)

Congenital heart defects

Heart attack (Myocardial Infarction)

History of previous heart surgery

Increased or high blood pressure

Improper functioning of the heart’s pacemaker (or Sick Sinus Syndrome)

Lung disease

Metabolic imbalance such as an overactive thyroid gland

Use of stimulants such as alcohol, caffeine, tobacco and certain medications

Sleep apnoea (pauses in breathing while asleep)

Stress due to illnesses such as pneumonia or surgery

Viral infection

3. The role of the autonomic nervous system in AF

Nearly all arrhythmias, including AF, are triggered by the autonomic nervous system. This is the intrinsic (subconscious) nervous system that governs day-to-day bodily functions that we are unaware of, such as control of heart rate, blood pressure, temperature, peristalsis (gut movement), etc.

The fright or flight response, is one such strong manifestation of the autonomic nervous system and allows you to run for your life (or fight for it) in a threatening situation.

The opposite of this is called the “rest and digest” response – which is where for example after a meal, you get into a deeply relaxed state to allow digestion and recovery/rest of bodily functions.

The relevance of the autonomic nervous system is that some (up to 60%) of individuals may well experience AF which is triggered by autonomic states. For example, when AF occurs with exercise, infection or caffeine-ingestion, then these are clear “fright or flight” triggers for AF. Less commonly know about is the vagally-mediated AF triggers – which is when AF is triggered by:

A large meal Dizzy/bubbly drinks During sleep at night Several hours after exertion (i.e. whilst recovering from a heavy workout).

In these instances, AF is said to be vagally-mediated (or vagal AF).

4. Signs and Symptoms of Atrial Fibrillation

With AF, you may experience:

Chest pain

Heart palpitations, which is an odd sensation of irregular heartbeats, with weak and strong beats, which may feel like a flip-flopping, racing, and uncomfortable sensation in the chest

Dizziness

Fatigue or weakness

Lightheadedness

Inability to exercise

Shortness of breath

5. Diagnostic Investigations of AF

To diagnose AF, your doctor may assess your symptoms, conduct a review of your medical history and a thorough physical exam for signs on AF and complications such as heart failure. Your specialist may order tests to accurately diagnose AF including:

Blood tests. To help rule out abnormal blood count, thyroid problems, and heart failure.

Chest X-ray. Your doctor may order a chest X-ray to diagnose conditions other than atrial fibrillation that may explain your signs and symptoms.

Echocardiogram. This test is noninvasive and uses ultrasound waves to produce a moving video image of your heart and its underlying structures in motion. Another form of echo is a transesophageal echocardiography, wherein your doctor may insert a tube with a transducer down your esophagus to exclude blood clots in your heart, which is typically done prior to a cardioversion or ablation procedure.

Electrocardiogram (ECG). This is important as it is the primary diagnosing tool for AF.

Event recorder. This is a portable ECG device that monitors your heart activity for a week or two depending on your doctor’s advice. You will be asked to activate it when you feel a fast heart rate.

Holter monitor. This is another portable ECG device worn on a shoulder strap or belt, where it monitors your heart’s activity for between 24 and 72 hours. This aims to provide your doctor with a continued monitoring of your heart rhythm at the time of your symptoms. You will be asked to press a button, so an ECG strip will be printed during an episode of AF.

Treadmill Stress Test. Also known as exercise testing, stress testing involves running tests on your heart while you’re running on a treadmill.

Sleep apnoea screening. This is a wrist device that can be fitted easily which you can wear overnight. This screening test will be able to accurately diagnose sleep apnoea, which is a significant emerging risk factor for AF.

Dr. Boon Lim will be able to provide all these state-of-the-art diagnostic tests in modern comfortable surroundings. Please contact us to arrange this.

6. Atrial Fibrillation Treatment

Your treatment for atrial fibrillation will depend on a lot of factors and this includes the symptoms you experience, how long have you’ve had it and the underlying cause or triggers of AF.

The primary treatment goals are:

A. To decrease your risk of stroke

B. To reset your heart rate and rhythm

A. Decreasing stroke risk

Experiencing AF and undergoing treatments for AF may put you at risk for developing blood clots in your heart. If these blood clots become dislodged from the heart, and pumped into the blood vessels in the brain, you may suffer with a stroke. Your risk of stroke is determined by risk factors such as:

Congestive Heart Failure

Hypertension

Age (>65yo)

Diabetes

Stroke, or previous transient ischaemic attack (TIA or mini-strokes which fully resolve)

Vascular Disease (such as previous heart attack, peripheral vascular disease)

Sex (Female above 65yo)

These risk factors may be summarized as the CHA2DS2VASc, and your doctors will ask you all these questions above when assessing whether you should be started on anti-coagulant drugs.

Preventing blood clots by using anticoagulants

Your doctor may prescribe anticoagulants or blood-thinning medications. They are:

Warfarin (Coumadin) is the oldest drug to avoid blood clots. Regular blood monitoring to check levels (INR – International Normalised Ratio) is advised to keep the levels well-controlled.

Apixaban (Eliquis), Dabigatran (Pradaxa), Rivaroxaban (Xarelto), and Edoxaban (Lixiana) are termed Direct Oral Anticoagulants (DOAC) and are agents which have been introduced to replace warfarin as good alternatives. The immediate advantage of these are that they can be prescribed without the need for continuous lifelong monitoring, although they have similar effectiveness, and bleeding risks as warfarin. This means that your doctors may offer you these agents as a useful alternative to warfarin.

Aspirin, which is an antiplatelet drug, is no longer routinely recommended to prevent strokes in AF as a sole agent.

It may have a role, in combination with an anticoagulant drug, in patients who have had a past history of heart attacks or coronary artery stenting, but please be guided by your cardiologist on this. Other antiplatelet drugs include clopidogrel and ticragrelor.

Always check with your cardiologist before stopping any of these antiplatelet drugs.

B. Resetting your heart’s rate and rhythm

This is done through Cardioversion, a method used to reset to normal your heart rate and regular (sinus) rhythm.

A cardioversion may be offered depending on how long you’ve had AF and the underlying cause.

Cardioversion Methods:

Cardioversion using drugs

Depending on your likelihood of restoring normal rhythm, your doctor may prescribe a trial of drugs to cardiovert you. These are termed anti-arrhythmic drugs, and include agents such as amiodarone, flecainide, sotalol and propafenone. Your doctor will usually give you a trial of these drugs for at least 3 months to see if you are likely to cardiovert at home (termed spontaneous cardioversion), without need for a shock.

However, these drugs may fail to cardiovert you, in which case, the next step would be to arrange an electrical cardioversion.

Electrical cardioversion

This procedure is usually performed under a short general aneasthetic. Once asleep, an electrical shock is delivered to your heart through patches placed on your chest.

The shock stops your heart’s beat momentarily before normal rhythm (termed sinus rhythm) starts again.

Controlling your heart rate:

Your doctor may prescribe medications to control and restore your heart rate to normal. These include the following:

Digoxin helps control your heart rate at rest, but not during physical activity.

Beta blockers causes untoward side effects such as hypotension or low blood pressure.

Calcium channel blockers are not prescribed if you have low blood pressure or heart failure.

If performing cardioversion and prescribing medications such as beta-blockers does not resolve your symptoms during AF, your doctor might recommend more invasive procedures that aim to restore normal rhythm.

These include:

Atrioventricular (AV) node ablation and pacemaker insertion. If all other treatment modalities do not work for you, your doctor might recommend an AV node ablation.

In this type of ablation, through a thin tube, radiofrequency is applied to prevent the atria from sending electrical impulses to the heart’s ventricles. A pacemaker is implanted prior to this procedure to provide electrical impulses to your heart.