Medically Reviewed By: Dr Paul Lim – MBBS, M.Med (Int Med), MRCP (UK), FAMS (Cardiology)
Atrial fibrillation — often called AFib or AF — is the most common type of irregular heartbeat in adults. The upper chambers of the heart beat rapidly and chaotically instead of in a steady rhythm, which can cause palpitations, fatigue and breathlessness, and significantly raises the risk of stroke. Modern treatment, started early, greatly reduces these risks.
Senior Consultant Cardiologist & Cardiac Electrophysiologist
Dr Paul Lim subspecialises in heart rhythm disorders, including atrial fibrillation. He performs catheter ablation, pacemaker and defibrillator implantation, and manages anticoagulation and rhythm-control strategies for AFib patients. He completed advanced fellowship training at Barts Heart Centre, London under Singapore’s HMDP award.
Atrial fibrillation — often called “AFib” or “AF” — is the most common type of irregular heartbeat (arrhythmia) in adults. Up to 1 in 3 people may develop it during their lifetime.
In a normal heart, the upper chambers (atria) beat in a steady, coordinated rhythm. In atrial fibrillation, the atria beat rapidly and irregularly — sometimes more than 300 times per minute — instead of pumping blood effectively. This can cause blood to pool in the heart, increasing the risk of blood clots, stroke, and other serious complications.
In Singapore, atrial fibrillation is a growing public health concern as the population ages. The prevalence rises sharply after age 65, and AFib is one of the leading causes of preventable stroke locally. The good news is that with proper assessment and treatment, the major risks of AFib — stroke and heart failure — can be greatly reduced.
No visible P waves — a chaotic, wavering baseline replaces the normal flat line between beats, and QRS complexes fall at unpredictable intervals. This “irregularly irregular” pattern is the hallmark of AFib and can be confirmed with a simple 12-lead ECG in the clinic.
Many people with AFib notice symptoms, but a significant number do not. About 10 to 40 percent of people with AFib are asymptomatic and may only discover the condition during a routine check, a smartwatch alert, or after a complication like a stroke.
Common symptoms include:
Call 995 or go to the nearest A&E immediately if you experience chest pain, sudden severe shortness of breath, fainting, or signs of a stroke (sudden weakness on one side of the body, trouble speaking, facial drooping, or vision changes). Remember F.A.S.T.: Face drooping, Arm weakness, Speech difficulty, Time to call 995.
Note: AFib symptoms overlap with many other heart and non-heart conditions. A diagnosis can only be confirmed with an ECG — if you are unsure, please book a specialist consultation.
A normal resting heart rate is 60–100 beats per minute (BPM). In AFib the atria fire chaotically at over 300 times per minute, and the lower chambers (ventricles) often respond with a fast, irregular pulse — commonly 100–160 BPM at rest. Drag the slider to feel the difference between a normal pulse and a fast, AFib-like rate.
Normal resting heart rate. Most healthy adults sit in this range at rest — this is what a healthy conduction system produces when everything is working correctly.
Suspect AFib? Get a 12-lead ECG and proper specialist evaluation.
AFib develops when the electrical signals in the heart's upper chambers become disorganised. This is often the end result of slow changes in the heart's structure or electrical system over time. Most patients have more than one contributing factor.
Age is also a major factor — AFib becomes more common as people get older, particularly after age 65. In some patients no single cause is obvious, but in most a combination of high blood pressure, structural heart disease, sleep apnoea, and lifestyle factors can be identified and treated.
AFib is classified based on how long episodes last and how they respond to treatment. The type matters because it influences your treatment plan and what to expect long-term.
Episodes come and go on their own, usually lasting less than 7 days and often less than 48 hours. Many patients have only a few short episodes a year; others have multiple episodes a week. Paroxysmal AFib is often the most amenable to catheter ablation, with reasonable long-term success.
Episodes last longer than 7 days, or require treatment (medication or electrical cardioversion) to restore normal rhythm. Persistent AFib usually represents a more advanced stage in which the atria have begun to remodel.
Continuous AFib lasting more than 1 year. Restoring normal rhythm becomes progressively harder as the atria scar and enlarge, but a rhythm-control approach (including ablation) may still be worth attempting in selected patients.
Ongoing AFib where the patient and doctor have decided to stop trying to restore normal rhythm. The focus shifts entirely to rate control and stroke prevention. Patients can still live well with permanent AFib provided anticoagulation is appropriate and the heart rate is controlled.
AFib is diagnosed with an electrocardiogram (ECG) — a simple, painless test that records the heart's electrical activity for about 10 seconds. Because AFib often comes and goes, additional ambulatory monitoring may be required if the resting ECG is normal.
Your cardiologist will ask about symptoms, triggers, family history and existing health conditions, and check your pulse and blood pressure. An irregular pulse is the most reliable bedside clue to AFib.
The definitive first test. AFib has a characteristic appearance — no clear P waves and irregularly irregular QRS complexes. If the ECG captures AFib, the diagnosis is confirmed.
If AFib is suspected but the resting ECG is normal, a wearable monitor catches intermittent episodes:
A scan of the heart to check chamber size, valve function, and pumping strength. The size of the left atrium and the ejection fraction influence both treatment choice and prognosis.
Thyroid function, kidney function, full blood count, and sometimes a clotting profile. Thyroid problems and anaemia can trigger or worsen AFib and need to be excluded.
A treadmill stress test or CT scan of the coronary arteries may be ordered to rule out underlying coronary artery disease, especially in patients with chest discomfort or risk factors. A CT or MRI of the atria is sometimes performed before catheter ablation.
AFib itself is rarely immediately life-threatening, but its complications can be very serious. Understanding the risks is the first step to addressing them.
The good news is that with proper treatment — particularly anticoagulation in patients at meaningful stroke risk — these risks can be greatly reduced.
Modern AFib care focuses on three goals. Your cardiologist will discuss which combination suits you based on your age, symptoms, stroke risk, and the type and duration of AFib.
For most people with AFib, the single most important treatment is preventing stroke. Stroke risk is assessed using the CHA2DS2-VASc score, which considers age, sex, and conditions such as heart failure, hypertension, diabetes, prior stroke and vascular disease.
Rate control slows a fast AFib heart rate to a comfortable level using:
Rhythm control aims to restore and maintain normal sinus rhythm. Increasingly, early rhythm control is favoured for many patients because of evidence that it improves outcomes when started within the first year of diagnosis.
Strong evidence now shows that addressing risk factors slows AFib progression and improves treatment outcomes:
Most people with AFib live full, active lives once the condition is well managed. Here is how to keep things on track, and what helps reduce risk in the first place.
Age and genetics cannot be changed, but the following measures meaningfully reduce risk:
For people with known risk factors, opportunistic screening with a pulse check or single-lead ECG is reasonable from age 65 onwards. Many cases of AFib are picked up incidentally on a routine ECG or smartwatch.
Answers to the most common questions about atrial fibrillation, its risks, and how it is treated.
Atrial fibrillation — often called AFib or AF — is the most common type of irregular heartbeat in adults. The upper chambers of the heart (atria) beat rapidly and irregularly, sometimes more than 300 times per minute, instead of pumping blood effectively. This can cause symptoms such as palpitations and fatigue, and raises the risk of blood clots and stroke.
AFib itself is rarely immediately life-threatening, but its complications can be serious. The biggest risk is stroke — AFib raises stroke risk by up to 5 times. Other risks include heart failure, dementia, and reduced quality of life. With modern treatment, particularly anticoagulation, most of these risks can be substantially reduced.
High blood pressure is the single most common risk factor. Other major contributors are age, coronary artery disease, heart valve disease, heart failure, obesity, obstructive sleep apnoea, diabetes, an overactive thyroid, excessive alcohol, and a family history of AFib. Many patients have more than one contributing factor.
Common symptoms include palpitations (a fluttering, racing or pounding sensation), shortness of breath, fatigue, dizziness, chest discomfort and reduced exercise tolerance. About 10 to 40 percent of people with AFib have no symptoms at all and may only discover the condition during a routine check, a smartwatch alert, or after a stroke.
AFib is diagnosed with an electrocardiogram (ECG). Because AFib can come and go, a Holter monitor (24 hours to 7 days), an event recorder or an implantable loop recorder may be needed to catch intermittent episodes. An echocardiogram is usually performed to check the heart's structure, along with blood tests for thyroid and kidney function.
In AFib the atria do not contract effectively, so blood can pool in a small pouch called the left atrial appendage. Stagnant blood can form clots. If a clot dislodges, it can travel through the bloodstream to the brain and block an artery — causing a stroke. This is why anticoagulation, based on the CHA2DS2-VASc score, is central to AFib management.
Paroxysmal AFib comes and goes on its own within 7 days. Persistent AFib lasts more than 7 days or needs treatment to stop. Long-standing persistent AFib lasts more than a year. Permanent AFib is ongoing AFib where the decision has been made to stop trying to restore normal rhythm and focus instead on rate control and stroke prevention.
Modern AFib care focuses on three goals: reducing stroke risk with anticoagulation, controlling symptoms with rate or rhythm-control therapy, and addressing risk factors such as blood pressure, weight, sleep apnoea and alcohol. Treatment options include direct oral anticoagulants (DOACs), beta-blockers, antiarrhythmic medication, electrical cardioversion and catheter ablation.
For many patients with paroxysmal AFib, catheter ablation can effectively eliminate AFib episodes — though AFib can recur, especially if underlying risk factors are not addressed. For persistent or long-standing AFib the goal is usually control rather than cure. Even so, modern catheter ablation has substantially improved long-term outcomes.
No. Current cardiology guidelines do not recommend aspirin for stroke prevention in AFib because it is much less effective than anticoagulants while still carrying a bleeding risk. Patients at significant stroke risk should be on a direct oral anticoagulant (DOAC) or, in selected cases, warfarin.
Strong evidence shows that addressing risk factors slows AFib progression. Weight loss of 10 percent or more in overweight patients substantially reduces AFib burden. Treating obstructive sleep apnoea, controlling blood pressure to below 130/80 mmHg, limiting alcohol, and regular moderate-intensity exercise all help. These measures work alongside, not instead of, medical therapy.
With proper treatment — particularly stroke prevention with anticoagulation, rate or rhythm control, and management of underlying risk factors — many people with AFib live a normal lifespan. Untreated AFib raises the risk of premature death from stroke and heart failure, which is why early specialist evaluation matters.