Medically Reviewed By: Dr Paul Lim – MBBS, M.Med (Int Med), MRCP (UK), FAMS (Cardiology)
Premature Ventricular Contractions (PVCs & Ectopic Beats)
Premature ventricular contractions are extra beats fired early from the heart’s lower chambers, and in an otherwise normal heart they are not necessarily a sign of disease. Unsettled by a heart that keeps skipping? Dr Paul Lim is a patient listener, and will tell you how many you are having, where they come from, and whether that number changes anything.
Dr Paul Lim Chun Yih
Senior Consultant Cardiologist & Electrophysiologist
Clinical Experience
Assessed by Dr Paul Lim
Senior Consultant Cardiologist & Cardiac Electrophysiologist
Dr Paul Lim subspecialises in the heart’s electrical system, which is where ectopic beats come from. He counts the burden on ambulatory monitoring, checks the pumping function on echocardiography, and where the beats warrant it, maps and treats the responsible focus by catheter ablation. He completed advanced fellowship training at Barts Heart Centre, London under Singapore’s HMDP award.
What Is a Premature Ventricular Contraction?
A normal heartbeat begins in the sinus node, a cluster of cells in the top right chamber that sets the pace. The signal spreads down through the heart in an orderly sequence, and the two lower chambers, the ventricles, do the pumping.
A premature ventricular contraction breaks that sequence. A small patch of tissue inside one of the ventricles fires on its own, before the sinus node has sent the next signal. The beat is premature because it arrives early, and ventricular because it starts in the lower chambers rather than at the top. You may also see it written as a ventricular ectopic beat, a premature ventricular complex, a ventricular premature beat or a ventricular extrasystole. These are all the same finding.
They are not rare. Extra or skipped beats are a common and usually harmless experience: monitor a hundred healthy adults for a day and most recordings will contain a few. People reach a cardiologist for one of two reasons. The beats have become noticeable, or a routine ECG picked them up and the report used a word nobody explained.
You are not missing a beat, you are getting an extra one
The phrase “skipped beat” describes the sensation accurately and the mechanism backwards. Nothing is skipped. An extra beat arrives too early and too weakly to be felt, and the heart then waits a moment before resuming. That wait is the gap you notice.
What PVCs Look Like on an ECG
A PVC is recognised by two features: it comes early, and because it starts in the ventricle rather than travelling down the normal wiring, its QRS complex is wide and oddly shaped instead of narrow and upright. Watch what happens immediately after each one.
Holter report in hand and none the wiser? Bring it to Dr Paul Lim and have the numbers put in context.
Why a PVC Feels Like a Skipped Beat
Three things happen in quick succession, and only the third one is usually felt.
The extra beat fires early, and goes unnoticed
Arriving ahead of schedule, the ventricle has had less time to fill. It contracts on a part-full chamber, ejects very little, and produces only a faint pulse. Many people never feel this beat at all.
The heart pauses while it resets
The extra beat does not reset the sinus node, which carries on to its own timetable. But the ventricle has just contracted, so it is not ready when the next signal arrives and that one passes without producing a beat. The result is a compensatory pause: the gap from the beat before the extra one to the beat after it usually spans two normal cycles rather than one. This is the skip, the drop, or the lift in the chest. It is most noticeable lying in bed, where the resting heart rate is slower and nothing else competes for your attention.
The next beat lands harder than usual
During that longer pause the ventricle fills more than usual. The next sinus beat has a fuller chamber to empty, so it contracts more forcefully. That is the thump against the breastbone: a normal heart responding normally to a longer filling time.
Symptoms of PVCs
Plenty of people have PVCs and feel nothing whatsoever. Where there are symptoms, they are usually these.
Commonly described
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A skipped or missed beatThe gap, followed by a definite thud.
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A flip or flutter in the chestSometimes felt up in the throat or neck.
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A single heavy thumpOut of nowhere, often while sitting still or lying down.
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An irregular pulseFelt at the wrist, and it may seem to stumble.
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A pulse that reads slowThe weak extra beats may be too faint to register at the wrist or on a fitness tracker, so the number understates how often the heart is actually contracting.
Less common, and worth mentioning at your consultation
- Light-headedness at the moment of the beat.
- Breathlessness or reduced exercise tolerance, which goes with a high burden rather than the occasional beat.
- Fatigue built up gradually over months.
- Anxiety about the heart that has begun to shape your day: checking your pulse repeatedly, avoiding exertion, sleeping badly. Worth raising, and an explanation is often the treatment.
Get urgent help if a skipped beat comes with any of these
Call 995 or go to the nearest A&E if the sensation is accompanied by chest pain that is severe or lasts more than a few minutes, by fainting or a blackout, by severe breathlessness, or by a racing heart that will not settle and leaves you unwell. These are not typical of ordinary ectopic beats, and they need assessing on the day rather than at a clinic appointment.
PVC Burden: What the Percentage Means
The question is rarely whether you have PVCs. It is how many, out of how many beats in total.
Your heart beats roughly 100,000 times a day, so a report saying “1,200 ventricular ectopics” means little without the denominator. Cardiologists work in burden: the proportion of all recorded beats that were PVCs. Twelve hundred out of a hundred thousand is about 1.2 per cent, which in a structurally normal heart is unremarkable.
Burden matters because of one specific risk. A heart that spends a large share of its beats contracting out of sequence, month after month, can gradually lose pumping strength. That is PVC-induced cardiomyopathy. It is uncommon, it develops quietly in people who feel well, and it usually reverses once the PVCs are controlled.
| Burden | What it generally means | Usual approach |
|---|---|---|
| Under 1% | Within the range found in a great many healthy adults. | An echocardiogram to confirm the heart is structurally normal, then reassurance. Treatment only if the symptoms themselves are troublesome. |
| 1–10% | More than average, but below the level associated with a fall in pumping function. | Look for a trigger and a cause. Treat if the symptoms warrant it. Repeat the echocardiogram periodically rather than once. |
| Above 10% | The range in which sustained PVCs are recognised as capable of weakening the heart muscle over time. | Treatment is usually discussed even without symptoms, with monitoring of the pumping function. Medication first, ablation where the burden stays high. |
| Any burden, with a reduced ejection fraction | The pumping function has already fallen. The PVCs may be the cause, or may be a consequence of an underlying heart problem. | Both possibilities are investigated together. Suppressing the PVCs is both a treatment and a test: if the function recovers, the PVCs were driving it. |
Why the thresholds are approximate
These are the bands in general use, not a line dividing safe from unsafe. Published thresholds for a fall in pumping function range from under 10 per cent to over 20 per cent, depending on the study and on other factors: how wide the beats are, where in the ventricle they start, and what the pumping function was to begin with. A single day’s recording may not be typical either, since PVCs come and go with sleep, stress, illness and caffeine. Your number is read alongside your echocardiogram, your symptoms and your history.
What Causes PVCs
In most people no disease is found, and the beats come from a small patch of tissue that is simply more excitable than its neighbours. The commonest site is the right ventricular outflow tract, the part of the right ventricle just below the pulmonary valve, and that origin matters later because it is also the most straightforward one to treat.
Everyday triggers
- Caffeine, in coffee, tea and energy drinks.
- Alcohol, particularly the day after a heavier evening.
- Nicotine, smoked or vaped.
- Short or broken sleep. Many people trace a bad run to a week of poor nights.
- Stress and anxiety, which raise circulating adrenaline.
- Dehydration, easy to fall into in Singapore’s climate.
- Stimulant medication, including some decongestants and asthma inhalers.
Body-wide causes worth excluding
- Low potassium or low magnesium. Both are simple blood tests and both are correctable.
- An overactive thyroid, which makes the heart more excitable generally.
- Anaemia, which raises the workload on the heart.
- Obstructive sleep apnoea, which is under-recognised and strongly associated with night-time arrhythmia.
Heart conditions that produce PVCs
These are why an echocardiogram is done rather than assumed, even when someone feels well.
- Coronary artery disease, or scar tissue from a previous heart attack.
- Cardiomyopathy, where the heart muscle itself is weakened, thickened or scarred.
- Heart valve disease, which stretches and remodels the chambers over time.
- Long-standing high blood pressure, which thickens the left ventricle.
- Myocarditis, inflammation of the heart muscle, usually following a viral illness.
PVCs and PACs: What the Difference Is
Reports often mention both. They are the same event in different chambers, and they can feel identical.
| Feature | PAC (premature atrial contraction) | PVC (premature ventricular contraction) |
|---|---|---|
| Where it starts | In an upper chamber (atrium) | In a lower chamber (ventricle) |
| On the ECG | A narrow complex, usually with an odd or early P wave in front of it | A wide, distinctly shaped complex with no P wave in front of it |
| The pause after | Usually incomplete, so the rhythm resets a little early | Usually a full compensatory pause, which is why the following beat feels stronger |
| How it feels | Often indistinguishable from a PVC | Often indistinguishable from a PAC |
| What a high burden is linked to | A greater likelihood of developing atrial fibrillation later | A fall in pumping function, if sustained over months |
| General outlook | Regarded as the more benign of the two | Benign in a normal heart; assessed more closely where the burden is high or the heart is not normal |
Three or more ventricular beats in a row is no longer a couplet. Reports call it non-sustained ventricular tachycardia, and it is assessed differently — see tachycardia.
Concerned about extra beats, or would simply like a second opinion? Talk to Dr Paul Lim.
How PVCs Are Assessed
Two questions are being answered: how many are there, and is the heart otherwise normal. Everything below follows from those.
Electrocardiogram (ECG)
A standard ECG records about ten seconds. A PVC falling in that window is captured, and its shape indicates roughly where in the ventricle it came from. A normal ECG does not rule PVCs out: it means none occurred during those ten seconds, which is why it is rarely the last word.
Holter and extended monitoring
A Holter monitor is a small recorder worn for 24 hours or longer, and it produces the burden figure. It also shows the pattern: whether the beats cluster at night, come as bigeminy, share one shape (unifocal) or several (multifocal), and whether they match the moments you felt something, which is why you keep a short symptom diary. If the beats are intermittent, a longer recording gives a more representative number.
Echocardiogram
A 2D echocardiogram answers the structural question: chamber size, valve function, and whether the pumping function (the ejection fraction) is normal. This is the test that most changes what PVCs mean, because the same beats carry one interpretation in a structurally normal heart and quite another in a weakened one. Where the burden is high, the scan is repeated over time rather than done once.
Treadmill stress test
A treadmill stress test shows what the beats do as the heart rate rises. PVCs that fade with exertion behave as benign ones usually do. PVCs that become more frequent with exercise, or appear during recovery, prompt a closer look.
Blood tests, and anything further
A small panel covers the correctable causes: potassium and magnesium, thyroid function, and a full blood count for anaemia. Finding something here occasionally resolves the whole problem. Where the pumping function is reduced, or the beats appear to come from an unusual site, cardiac MRI can show scar in the heart muscle that an echocardiogram cannot. An electrophysiology study is not a routine test here; it is done as part of an ablation, to map where the beats originate before treating them.
How PVCs Are Treated
Treatment is aimed at one of two targets: the symptoms, or the burden. Which one you are treating decides how far you go.
An explanation, and leaving them alone
Where the heart is structurally normal and the burden is low, no treatment is needed, and this is the commonest outcome. Many people find the beats recede once they understand what is happening, because much of what made them intrusive was the attention being paid to them. Knowing the echocardiogram is normal is usually what lets that attention go.
Removing the trigger
Where a pattern is identifiable, acting on it costs nothing and is sometimes sufficient: cutting back caffeine, moderating alcohol, treating sleep apnoea, protecting sleep, correcting a low potassium or magnesium level, or reviewing a stimulant medication with the doctor who prescribed it. Note what preceded each bad run for a fortnight and the pattern often emerges on its own.
Medication
Beta-blockers are the usual first choice. They dampen the effect of adrenaline, which reduces the number of beats in many people and makes those that remain less forceful and so less noticeable. Calcium-channel blockers are an alternative where a beta-blocker is unsuitable. Antiarrhythmic drugs suppress PVCs more effectively but carry more side effects, so they are reserved for a high burden or symptoms that have not responded to the simpler options.
Catheter ablation
Catheter ablation treats the problem at source. Fine catheters are passed to the heart through a vein in the groin, the site firing the extra beats is mapped, and that small area of tissue is treated so it stops firing. It works best when the beats come consistently from a single focus, which is frequently the case for the right ventricular outflow tract.
It is considered where the burden threatens the pumping function, where symptoms persist despite medication or medication is not tolerated, or where the ejection fraction has fallen and suppressing the PVCs may let it recover. One practical point: the beats must be occurring during the procedure to be mapped, so a quiet day can limit what is achievable.
Ablation for ectopic beats has a published physician fee benchmark of S$10,900 to S$15,400 before GST. That is the doctor’s fee alone. Hospital facility charges, anaesthesia and consumables are billed separately, and the actual fee varies with the complexity of the case. Our cardiology fees page sets out consultation and test charges.
When to See a Cardiologist About Extra Beats
Book an appointment if any of the following applies to you.
- The beats are frequent enough to notice most days, or have become more frequent than they were.
- A report has named ventricular ectopics, bigeminy or couplets, or your burden is above about 10 per cent, and nobody has explained what that means for you.
- You have known heart disease, a weakened heart muscle, or a previous heart attack.
- There is a family history of sudden cardiac death, cardiomyopathy or an inherited rhythm condition.
- The beats come with fainting, chest pain or breathlessness, particularly during exertion, or get worse rather than better when you exercise.
- You are concerned, or would simply like a second opinion on a result you have been given.
Both clinics carry out the ECG, Holter and echocardiogram on site, so the assessment is usually completed in one or two visits. More on when a cardiology referral is worthwhile.
Book a Consultation for PVCs
See Dr Paul Lim about extra beats on your ECG or Holter: how many there are, where they come from, and whether they need treating.
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PVC FAQ
The questions people ask most often after a monitor comes back reporting ventricular ectopic beats.
What is a premature ventricular contraction (PVC)?
A premature ventricular contraction is an extra heartbeat that starts in one of the heart’s two lower chambers rather than in the sinus node, and fires before the next normal beat is due. On an ECG it appears as a wide, oddly shaped complex interrupting the regular rhythm. Ventricular ectopic beat, premature ventricular complex, ventricular premature beat and ventricular extrasystole all mean the same thing. They are common: monitor almost any adult for a day and some will show up.
Why do PVCs feel like a skipped beat?
The extra beat is usually too weak to feel, because it fires before the ventricle has filled properly. A pause follows, usually long enough to span two normal beats rather than one, and during it the ventricle fills more than usual, so the next beat contracts more forcefully. That beat after the gap is the thump, the flip or the skip. What you feel is the pause and the beat after it, not the extra beat itself.
Are PVCs dangerous?
In a heart that is structurally normal, occasional PVCs are regarded as benign and often need no treatment beyond an explanation. The assessment changes if there is underlying heart disease, if the beats are very frequent, or if they come with fainting, chest pain or breathlessness on exertion. That is why the first step is almost always an echocardiogram to check the heart’s structure and pumping function, alongside a monitor to count how many PVCs there actually are.
How many PVCs a day is too many?
Cardiologists work in burden, the percentage of all heartbeats that are PVCs over a monitored period, rather than a raw count. Under about 1 per cent is common and generally not a concern in a normal heart. Above roughly 10 per cent, sustained over months, there is a recognised risk the heart muscle weakens, and the concern rises as the burden climbs. A 24-hour Holter is the usual way to measure it, and a longer recording where the figure is borderline.
Can PVCs weaken the heart?
A high PVC burden carried for months to years can reduce the heart’s pumping function, a condition called PVC-induced cardiomyopathy. It is uncommon, and the important feature is that it is usually reversible: when the PVCs are suppressed with medication or removed with catheter ablation, the pumping function typically recovers. This is the main reason a high burden is treated even in someone who feels well, and the reason an echocardiogram is repeated over time rather than done once.
Do PVCs go away, and can they be cured?
Often, yes. PVCs commonly settle on their own, and a run of them frequently fades once a trigger passes, such as sleep debt, caffeine or a stressful period, or once a low potassium level or thyroid problem is corrected. Medication suppresses them rather than removing them. The treatment that can end them permanently is catheter ablation, which locates the small area of ventricular tissue firing early and interrupts it. It works best when the beats come consistently from one focus.
Should I exercise if I have PVCs?
Many people with PVCs and a structurally normal heart exercise without restriction, and in some the beats become less frequent as the heart rate rises. The pattern needing assessment first is the opposite: PVCs that increase with exertion or appear during recovery, along with any fainting, chest pain or unusual breathlessness. A treadmill stress test shows which pattern you have. If you have felt faint while exercising, stop and have it assessed rather than working through it.
Are PVCs the same as atrial fibrillation?
No, and the difference matters. PVCs are single extra beats interrupting an otherwise normal rhythm, and they carry no stroke risk. Atrial fibrillation is a sustained, irregular rhythm from chaotic electrical activity in the upper chambers, and it does carry a stroke risk that usually needs assessing and often treating. Both can feel like a stumbling pulse, so they are told apart on an ECG rather than by sensation.
What is ventricular bigeminy?
Bigeminy is a pattern in which every second beat is a PVC, so normal and extra beats alternate. Trigeminy is every third beat, and a couplet is two in a row. The pattern itself does not make the beats more dangerous, but bigeminy produces a high burden by definition: run for hours, and roughly half the beats in that period are PVCs. It can also make the pulse at the wrist feel slow, since the weak extra beats may not register there.