Tachycardia in Singapore: Fast Heart Rate Causes, Symptoms and Treatment

Tachycardia (a fast heart rate, usually over 100 beats per minute at rest) has many possible causes – from the entirely normal response to exercise, fever or stress, to electrical faults in the heart that need specific treatment. Working out which type you have matters, because the answer determines whether you need reassurance, medication, a procedure or urgent care. This page explains the difference between sinus tachycardia and true arrhythmias, the dangerous ventricular forms, and how a fast heart rate is diagnosed and treated. It is general information and not a substitute for advice from your own doctor.

What Is Tachycardia?

Tachycardia means a resting heart rate above the normal range of roughly 60 to 100 beats per minute. Fast heart rates fall into two broad groups.

Sinus tachycardia is a fast but normal rhythm: the heart’s natural pacemaker (the sinus node) is simply firing quickly because the body is asking it to. Exercise, anxiety, fever, pain, dehydration, anaemia (low red blood cells), an overactive thyroid, caffeine and some medications all cause it. The treatment is to find and address the underlying driver.

Arrhythmic tachycardias are electrical faults in the heart itself. The rhythm often starts and stops abruptly, like a switch, regardless of what the body needs. The main types are:

• Supraventricular tachycardia (SVT) – a short-circuit involving the upper chambers, causing sudden bouts of regular racing at 150 to 220 beats per minute, common in younger adults; supraventricular tachycardia (SVT) is covered in detail on its own page.
• Atrial fibrillation and atrial flutter – chaotic or circular electrical activity in the upper chambers; atrial fibrillation causes a fast and irregular pulse and carries a stroke risk.
• Ventricular tachycardia and ventricular fibrillation – fast rhythms from the lower chambers, the most dangerous forms (see below).

Tachycardia Symptoms

• Palpitations – a racing, pounding or fluttering heartbeat
• Breathlessness, at rest or on mild exertion
• Dizziness or light-headedness
• Chest tightness or discomfort
• Reduced exercise tolerance and fatigue
• Near-fainting or fainting (syncope) – a warning sign that needs prompt assessment
• Some episodes, especially of atrial fibrillation, cause no symptoms and are found on a routine pulse check or wearable device

When to Seek Emergency Help

Call 995 if a fast heartbeat occurs together with:

• Chest pain or pressure
• Fainting or collapse
• Severe breathlessness
• Confusion, drowsiness, or a cold, clammy, pale appearance

A very fast rhythm that makes you feel faint is treated as an emergency until proven otherwise.

Causes and Risk Factors

• Everyday drivers of sinus tachycardia – stress and anxiety, caffeine and energy drinks, alcohol, poor sleep, fever, dehydration
• Medical drivers – anaemia, an overactive thyroid, infection, low blood pressure, stimulant medications
• Structural heart disease – coronary artery disease, a previous heart attack, heart failure, cardiomyopathy (heart muscle disease) and valve disease all predispose to arrhythmias, particularly the ventricular forms
• Electrical abnormalities – extra conduction pathways present from birth (causing SVT), and inherited conditions affecting the heart’s electrical channels
• Risk factors common in Singapore – hypertension, diabetes and obstructive sleep apnoea all increase the likelihood of atrial fibrillation with age

Ventricular Tachycardia and Ventricular Fibrillation: The Dangerous Forms

Fast rhythms arising from the ventricles (the heart’s main pumping chambers) are in a different category of seriousness.

Ventricular tachycardia (VT) is a fast, usually regular rhythm from the ventricles. Short runs may cause palpitations or dizziness; sustained VT can stop the heart pumping effectively and cause collapse. It most often occurs in hearts scarred by a previous heart attack or weakened by cardiomyopathy.

Ventricular fibrillation (VF) is chaotic electrical activity in which the ventricles quiver instead of pumping. Blood flow stops within seconds – VF is the rhythm behind most sudden cardiac arrests and is fatal within minutes unless corrected with a defibrillator shock.

People at significant risk of VT or VF – those with a weakened heart muscle, or survivors of a dangerous rhythm – may be offered an implantable cardioverter-defibrillator (ICD), a small device that continuously monitors the rhythm and automatically delivers a shock to stop a life-threatening arrhythmia.

How Tachycardia Is Diagnosed

• Electrocardiogram (ECG) – a resting electrocardiogram (ECG) identifies the rhythm immediately if the fast rate is present, and can show clues such as extra pathways or previous heart damage even between episodes.
• 24-hour Holter monitor – a 24-hour Holter monitor, or a 7-day or patch recording for infrequent episodes, captures the rhythm during normal life and links it to your symptoms.
• Echocardiogram – an ultrasound scan of the heart to check its structure and pumping strength.
• Blood tests – thyroid function, haemoglobin and electrolytes.
• Treadmill (exercise stress) test – for rhythms triggered by exertion.
• Electrophysiological (EP) study – an electrophysiological (EP) study maps the heart’s electrical circuits from inside via thin catheters, confirming the exact mechanism and often allowing treatment by ablation in the same session.

Treatment Options

Treatment depends entirely on the type of tachycardia:

• Sinus tachycardia – treat the underlying driver: hydration, sleep, reducing caffeine and alcohol, managing anxiety, or correcting anaemia or thyroid problems.
• Vagal manoeuvres – simple physical techniques, taught in clinic, can terminate an episode of SVT.
• Medication – beta-blockers or calcium channel blockers (drug classes that slow electrical conduction) are used to control the rate or prevent episodes; anti-arrhythmic drugs are used in selected cases, and anticoagulants (blood thinners) reduce stroke risk in atrial fibrillation.
• Catheter ablation – a keyhole procedure that treats the tissue causing the short-circuit; it is a standard treatment for SVT, atrial flutter and atrial fibrillation, and for some forms of VT.
• Electrical cardioversion – a controlled shock under sedation to restore normal rhythm in persistent atrial fibrillation or flutter.
• ICD implantation – for those at risk of dangerous ventricular arrhythmias; see our cardiac pacemakers and devices service for what device implantation involves.

When to See a Cardiologist

See a cardiologist if you have recurrent racing episodes, palpitations with dizziness, breathlessness or chest discomfort, an irregular pulse, or a fast heart rate flagged on a wearable device. Fainting during a racing episode, or a fast heart rate with known heart disease, warrants early assessment.

Frequently Asked Questions

Why is my heart racing for no reason?

There is usually a reason – commonly stress, caffeine, poor sleep, dehydration, fever or thyroid problems, or an electrical rhythm problem such as SVT. Episodes that start and stop abruptly point to an arrhythmia, and a Holter recording during an episode usually settles the question.

Is a heart rate of 120 dangerous?

During exercise, stress or fever, 120 is a normal response. At rest and unexplained, it deserves assessment – persistent resting tachycardia can strain the heart over time and may signal anaemia, thyroid disease or an arrhythmia.

What is the difference between SVT and ventricular tachycardia?

SVT arises above the ventricles and, while unpleasant, is rarely life-threatening in a normal heart. Ventricular tachycardia arises in the pumping chambers themselves, often in a damaged heart, and can be dangerous – it is treated far more aggressively, sometimes with an ICD.

Can tachycardia go away on its own?

Individual episodes often stop spontaneously, and sinus tachycardia settles when its trigger resolves. Electrical problems such as SVT or atrial fibrillation tend to recur, which is why definitive treatment such as ablation is often discussed.

Does anxiety cause tachycardia?

Yes – adrenaline from anxiety is a common cause of a fast heart rate. But the two can mimic each other, so abrupt or recurrent racing episodes are worth capturing on a monitor before being attributed to anxiety alone.