Understanding Arrhythmia: Diagnosis and Treatment in Singapore

Almost everyone has felt their heart do something odd at some point: a skipped beat, a brief flutter, a thump that makes you catch your breath. Most of the time this is harmless. Sometimes it is the first clue to an arrhythmia, a problem with the heart’s rhythm that may need treatment.

In this article I will explain what an arrhythmia actually is, what palpitations feel like and when they matter, the common types you may hear about, and why atrial fibrillation deserves special attention because of its link to stroke. I will also walk through how we diagnose arrhythmias in Singapore and the main ways we treat them. Most importantly, I will tell you the warning signs that mean you should call 995 straight away.

What is an arrhythmia?

Your heart has its own electrical system. In a normal heart, an electrical signal starts in the heart’s natural pacemaker, spreads in an orderly way, and produces a steady, regular beat of roughly 60 to 100 beats per minute at rest. An arrhythmia is simply an abnormal heart rhythm: the heart may beat too fast, too slow, or in an irregular pattern.

The medical names tend to describe exactly that. A rhythm that is too fast is a tachycardia. One that is too slow is a bradycardia. Some arrhythmias are little more than an occasional nuisance. Others can affect how well the heart pumps, and a small number can be dangerous. The job of assessment is to work out which kind you have.

What do palpitations feel like, and are they dangerous?

Palpitations are the awareness of your own heartbeat. People describe them in many ways: a skipped or missed beat, a flip or flutter, a pounding, or a sudden racing in the chest or neck. They can last a second or carry on for hours.

Most palpitations are not dangerous. They are often caused by ordinary things such as caffeine, alcohol, stress, lack of sleep, exercise, or an overactive thyroid. Extra beats coming from the heart, which I describe below, are extremely common and usually harmless.

That said, palpitations can sometimes be a sign of an arrhythmia that needs treating, and the safest approach is to have new, frequent, or troublesome palpitations checked. You should treat them as an emergency and call 995 if palpitations come with:

• Blacking out or feeling that you are about to faint
• Severe chest pain
• Severe breathlessness alongside a racing heart

These combinations can point to a rhythm that is affecting blood flow, and they should never be ignored.

What are the common types of arrhythmia?

There are many named arrhythmias, but in practice a handful come up again and again:

• Ectopic or extra beats. These are early beats that you may feel as a skip or a thump. They are very common, generally harmless, and most people do not need treatment beyond reassurance and cutting back on triggers such as caffeine.
• Atrial fibrillation (AF). The most common sustained arrhythmia, in which the upper chambers of the heart (the atria) beat in a fast, chaotic, irregular way. AF is the main focus of this article because of its link to stroke.
• Atrial flutter. A cousin of AF, caused by an organised but fast electrical circuit in the atria. It carries similar stroke risk and is often managed in a similar way.
• Supraventricular tachycardia (SVT). A sudden run of fast, regular heartbeats coming from above the ventricles. It can start and stop abruptly and is more common in younger people. It is usually not dangerous, though it can be very uncomfortable.
• Ventricular arrhythmias. These start in the heart’s main pumping chambers (the ventricles). Ventricular tachycardia (VT) and ventricular fibrillation (VF) are the most serious arrhythmias and can be life-threatening, which is why fainting with palpitations always needs urgent assessment.
• Bradycardia. A heart rate that is too slow, often because the heart’s natural pacemaker or wiring is ageing. It may cause tiredness, dizziness, or fainting, and sometimes needs a pacemaker.

You can read more in my overview of common heart conditions.

Why is atrial fibrillation so important?

Atrial fibrillation matters for one main reason: it raises the risk of stroke. When the atria fibrillate, blood does not empty from them cleanly. It can pool and form a clot, usually in a small pouch of the left atrium. If part of that clot breaks off, it can travel to the brain and cause a stroke. AF is associated with roughly a fivefold increase in stroke risk, and AF-related strokes tend to be more severe than other strokes.

This is a real issue in Singapore. AF becomes more common with age, affecting only a small percentage of people under 55 but around one in ten of those aged 80 and above. As our population ages, more people are living with AF, and a worrying number do not know they have it because AF can be completely silent or come and go (paroxysmal AF).

The good news is that this stroke risk can be greatly reduced. We assess each person’s individual risk using a simple scoring system (you may hear it called CHA2DS2-VASc, more recently refined as CHA2DS2-VA). At a lay level, it adds up risk factors such as older age, high blood pressure, diabetes, heart failure, and a previous stroke. The higher the score, the greater the benefit from blood-thinning treatment to prevent stroke. The decision is always individual, weighing the benefit against any bleeding risk, and it is one I make together with each patient.

How are arrhythmias diagnosed?

The central challenge is simple: to diagnose an arrhythmia, we usually need to catch it on a recording while it is happening. If your palpitations are occasional, that takes a little planning. The main tools are:

• ECG (electrocardiogram). A quick, painless recording of the heart’s electrical activity. If you are in an abnormal rhythm at the time, an ECG will usually show it. You can read what to expect during an ECG test.
• Holter monitor. A small portable ECG worn for 24 hours, 48 hours, or longer, recording every beat while you go about your day. This is very useful when symptoms occur most days.
• Event or loop recorders. For symptoms that are less frequent, a recorder worn for weeks, or a small device placed under the skin that can monitor for up to a few years, may be used to capture an elusive rhythm.
• Smartwatch and personal ECG devices. Many smartwatches can now flag an irregular rhythm or record a single-lead ECG. These can be genuinely helpful as an early alert, but a consumer device is not a diagnosis on its own. Any abnormal reading should be confirmed by a doctor.
• Exercise (stress) testing. Useful when symptoms come on with exertion, or to look at the heart’s rhythm and blood supply under stress. See what a cardiac stress test is and how it works.

I will also usually arrange blood tests and often an ultrasound of the heart to look for any underlying cause.

How are arrhythmias treated?

Treatment depends entirely on the type of arrhythmia and how much it is troubling you. The first step is often simply to treat the underlying cause, whether that is an overactive thyroid, high blood pressure, sleep apnoea, or excess caffeine and alcohol. From there, the options generally fall into a few groups.

Controlling the rate or the rhythm. For fast arrhythmias such as AF, we can either slow the heart rate to a comfortable level using rate-control drugs (for example beta-blockers), or try to restore and maintain a normal rhythm using rhythm-control (antiarrhythmic) drugs. My guide to navigating heart medications explains these classes in more detail.

Cardioversion. A controlled electrical shock, given under brief sedation, that can reset the heart back to a normal rhythm. It is a common and safe way to restore rhythm in AF and atrial flutter.

Catheter ablation. A keyhole procedure in which fine wires are passed to the heart through a vein, and the small areas of tissue driving the arrhythmia are carefully treated. For AF, this usually means isolating the pulmonary veins, where most of the abnormal triggers arise. Ablation can be very effective for AF, atrial flutter, and SVT. You can read more in my article on ablation therapy in Singapore.

Pacemakers and ICDs. A pacemaker is a small device that gently paces a heart that is beating too slowly. An implantable cardioverter defibrillator (ICD) is a similar device that watches for dangerous fast rhythms from the ventricles and can deliver a life-saving shock if needed.

Stroke prevention in AF. Running alongside all of the above, for many people with AF the single most important treatment is an anticoagulant (blood thinner) to prevent the clots that cause stroke. This is separate from controlling symptoms: a person can feel completely well and still need a blood thinner because of their stroke risk.

When should I worry, and when should I call 995?

A practical guide:

• Call 995 now if palpitations come with blacking out (or near-fainting), severe chest pain, or severe breathlessness with a racing heart. Call 995 too for any sudden weakness, facial droop, or difficulty speaking, which may be a stroke.
• Get seen promptly for palpitations that are new, frequent, lasting longer than usual, or coming with breathlessness or dizziness that settles.
• Mention it at a routine review if you have occasional brief skips or flutters and otherwise feel completely well, so we can confirm there is nothing more to it.

If in doubt, get checked. An arrhythmia is far easier to manage once we know exactly what it is.

The bottom line

Most palpitations are harmless, but some are the first sign of an arrhythmia, and atrial fibrillation in particular matters because of its link to stroke. The reassuring message is that arrhythmias are very treatable once diagnosed, and in AF the stroke risk can be greatly reduced. The key is to catch the rhythm, understand it, and treat both the symptoms and, where needed, the stroke risk.

If you have noticed palpitations, an irregular pulse, or have been told you may have atrial fibrillation, I provide comprehensive rhythm assessment at the Harley Street Heart and Vascular Centre in Singapore. Call +65 6235 5300 to arrange an appointment.

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Written by Dr Michael Ross MacDonald MB ChB, BSc (Hons), FRCP (UK), MD (Research), FESC (Europe) Senior Consultant Cardiologist at the Harley Street Heart and Vascular Centre, Singapore.

This article is general information, not a substitute for individual medical advice. If you are worried about palpitations or your heart rhythm, seek medical care, and in an emergency, call 995.

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