The Pulse Newsletter Expert heart health, in plain English. Fortnightly, from our clinicians. Subscribe →

Kathy Marinias RN

Professor Peter Barlis (MBBS, MPH, PhD, FESC, FACC, FSCAI, FRACP) is an Interventional Cardiologist and the founding editor of Heart Matters. With expertise in coronary artery disease, advanced cardiac imaging, and interventional cardiology — and fellowships of the European Society of Cardiology, the American College of Cardiology, and the Royal Australasian College of Physicians — he brings the highest level of clinical authority to everything published on this site. Heart Matters was founded on Professor Barlis's belief that patients who understand their condition are less frightened and better equipped to make decisions about their care. Every article on this site reflects that commitment.

Vitamin K and Your Arteries: What the Evidence Shows

vitamin K
Key Points
  • A new randomised trial, VitaK-CAC, found that a daily vitamin K2 supplement (a form called MK-7) modestly slowed the build-up of calcium in the heart’s arteries over two years compared with a placebo.
  • The effect was small. Calcium scores still rose in both groups, but they rose less in the people taking vitamin K2. The annual increase was reduced by about 19 points on the standard calcium scoring scale.
  • The study was small, with 180 participants, and ran into delays, so the findings are best seen as a promising early signal rather than proof that supplements prevent heart attacks.
  • Independent experts urge caution. We do not yet know whether slowing the rise in a calcium score actually translates into fewer heart attacks or strokes, and there is even debate about whether calcified plaque is the dangerous kind.
  • Vitamin K can interfere with warfarin and other blood-thinning medications, so nobody on an anticoagulant should start a supplement without speaking to their doctor first.

For years, the question of whether vitamin K supplements can protect the heart has been long on theory and short on evidence. A new clinical trial has now offered the clearest signal yet, and the answer is a carefully qualified “possibly”.

The study, called VitaK-CAC, was published recently in JAMA Cardiology. It found that a daily vitamin K2 supplement slowed the progression of calcium build-up in the coronary arteries over two years. The result is genuinely interesting. It is also a long way from a recommendation that everyone should head to the pharmacy.

What the Study Looked At

Researchers in the Netherlands recruited 180 adults who already had some calcium in their coronary arteries, measured using a CT scan that produces a coronary calcium score. Everyone in the study had a score between 50 and 400, which represents mild to moderate calcification.

Half the group took a daily dose of a vitamin K2 supplement known as MK-7, also called menaquinone-7. The other half took an identical placebo, an inactive tablet with no medicine in it, sometimes called a sugar pill. Neither the participants nor the researchers knew who was taking which until the study ended. This kind of design is the gold standard in medical research, because it stops expectation alone from influencing the result. The participants returned every six months for two years so their calcium scores and vitamin K blood levels could be tracked.

MK-7 is a specific form of vitamin K2. It is favoured in research because the body absorbs it well and it stays in the bloodstream longer than the more common vitamin K1 found in leafy greens.

What They Found

Calcium scores rose in both groups over the two years, which is what usually happens as calcification is a gradual, ongoing process. The difference was in how much they rose.

19 points the estimated reduction in the yearly rise of coronary calcium score among people taking vitamin K2, compared with placebo. VitaK-CAC trial, JAMA Cardiology, 2026

At the start, the two groups had similar average calcium scores, around 135 and 145. By two years, the placebo group had climbed to 214, while the vitamin K2 group reached 184. The slower climb in the supplement group was statistically significant, meaning it was unlikely to be down to chance alone.

Blood tests confirmed the supplement was doing something measurable. Vitamin K2 levels rose sharply in the treatment group, and a protein involved in keeping calcium out of artery walls behaved differently between the two groups. The researchers calculated that the calcium score and the vitamin K2 treatment were the two strongest predictors of how calcification changed over time.

Why Calcium in the Arteries Matters

Calcium in bones and teeth is essential. In artery walls it is a marker of atherosclerosis, the gradual furring and stiffening of blood vessels that underlies most heart attacks and strokes. The higher the calcium score, the more plaque a person tends to have, and the higher their cardiovascular risk.

The idea behind vitamin K2 is that it activates proteins which help direct calcium towards bones and away from artery walls, the same mechanism we explored in our explainer on vitamins D3 and K2. VitaK-CAC is the first reasonably robust trial to suggest the theory might hold up in the coronary arteries themselves.

A promising early result is not the same as a proven treatment. This trial opens a door. It does not tell us to walk through it just yet.

Why Experts Are Urging Caution

The researchers themselves were measured about their findings, and independent commentators were more cautious still. There are several reasons to hold back.

The first is size and design. With 180 participants and a study that suffered delays, this is a small trial. Small studies can produce real findings, but they need to be repeated in larger groups before anyone can be confident the result is reliable.

The second is more subtle. A calcium score is normally used to measure how much plaque a person has, not as something we actively try to lower. We have strong evidence that a high score predicts higher risk, but very little evidence about what happens when you deliberately slow the score’s rise. Lowering the number is not automatically the same as lowering the danger.

There is even a debate about whether calcified plaque is the dangerous kind. Statins tend to stabilise plaque and can leave behind calcium as a sign of that stability, a counter-intuitive effect we cover in our article on statins and your calcium score. Some experts worry that reducing calcified plaque could leave more of the softer, rupture-prone plaque behind. Nobody yet knows whether that concern is real. The earlier Danish AVADEC trial, which tested vitamin K2 in people with calcified aortic valves, found no significant benefit, underlining how unsettled this field still is.

What This Means for You

If you have had a calcium score done and it showed mild calcification, this study is worth being aware of, but it does not change current advice. The trial’s own authors said they would want larger studies before recommending vitamin K2 in any guideline, and other specialists who reviewed the work agreed they are not yet advising it for their patients.

Vitamin K2 is available without prescription and appears safe for most people at the doses studied. That is partly why some of the researchers said they would not object to people trying it. Safe and available, however, is not the same as proven to prevent heart attacks.

The most important practical point is a safety one. Vitamin K plays a central role in blood clotting, and it directly interferes with warfarin and similar anticoagulant medications. Anyone taking a blood thinner should not start a vitamin K supplement, or make large changes to their intake of vitamin K-rich foods, without first discussing it with their doctor or anticoagulation clinic.

More broadly, what is right for one person is not automatically right for another. Whether a supplement suits you depends on your own health history, the other medicines you take, and any conditions you live with. A supplement that is harmless for one person can interact with medication or be unsuitable for another. Your GP, cardiologist, or pharmacist knows your individual circumstances and is the right person to tell you whether vitamin K2 is sensible, safe, and compatible with the rest of your care.

For everyone, the foundations of heart health have not shifted: not smoking, managing blood pressure and cholesterol, staying active, and understanding your own cardiovascular risk factors. A supplement, even a promising one, sits well behind those.

Heart Matters Resource

When in Doubt, Get Checked Out

A calcium score, a new supplement, or a question about your medications is always worth raising with a professional who knows your history. If you are unsure whether something applies to you, that is reason enough to ask.

Read: When in Doubt, Get Checked Out →

Conclusion

VitaK-CAC is a thoughtful, well-conducted small trial that has nudged a long-standing theory a step closer to reality. It suggests that vitamin K2 might slow the build-up of calcium in the coronary arteries, and that finding deserves to be taken seriously and tested further.

For now, the sensible position is curiosity rather than action. If vitamin K2 interests you, the best next step is a conversation with your own cardiologist, GP, or pharmacist, who can tell you whether it is right for you and compatible with any other medicines or conditions you have. The science here is moving, and it is worth watching, but the proven path to a healthier heart still runs through the well-established basics.

Related Reading

Right Bundle Branch Block (RBBB): Why It Sounds Worse Than It Usually Is

right bundle branch block RBBB
Key Points
  • A right bundle branch block, often shortened to RBBB, is an electrical finding on an ECG. It means the signal travelling to the right side of the heart takes a slightly slower route than usual. It is not a blocked artery.
  • On its own, in a person who feels well and has a healthy heart, RBBB is common and usually harmless. It is found in roughly 1 in 100 adults, and the figure rises with age.
  • What matters is the context. A longstanding RBBB in someone with no symptoms is very different from a brand new RBBB that appears alongside chest pain or breathlessness.
  • RBBB becomes more important when it is new, when it occurs with symptoms, or when it appears together with other electrical changes on the same ECG.
  • Most people with isolated RBBB need no treatment at all. The block itself is not something that gets fixed, and in the majority of cases it never causes a problem.

Of all the phrases that can appear on an ECG report, “right bundle branch block” is one that sends people straight to a search engine, usually with a rising sense of alarm. The word block sounds ominous. It brings to mind a blocked artery, or something serious going wrong with the heart’s plumbing.

In the great majority of cases, it is neither of those things. This article explains what a right bundle branch block actually is, why it shows up, when it is nothing to worry about, and the smaller number of situations where it genuinely matters.

What the Bundle Branches Actually Do

Your heart has its own electrical wiring. Each beat begins with a signal that spreads across the upper chambers, then passes through a junction box in the centre of the heart and down into the two large lower chambers, the ventricles, which do the heavy pumping work.

From that junction box, the signal travels down two main cables, one to the left ventricle and one to the right. These cables are the bundle branches. They split into ever-finer fibres so that the electrical signal reaches every part of the muscle at almost the same instant, allowing both ventricles to squeeze together in a single coordinated beat.

A right bundle branch block means the cable to the right ventricle is not carrying the signal normally. The impulse is delayed or has to take a detour, reaching the right ventricle a fraction of a second later than it should. The heart still beats. The right ventricle still contracts. It simply gets its instruction by a slightly slower path.

This is quite different from a coronary artery problem, where the issue is blood supply rather than electrical signalling. If you would like to see the wiring for yourself, our interactive guide to your heart’s conduction system shows how the signal travels from the heart’s natural pacemaker down through the bundle branches to the ventricles.

What RBBB Looks Like on an ECG, in Plain Language

An ECG is a recording of the electrical signals that pass through your heart with every beat. Each beat produces a series of waves on the trace, and each wave reflects a different stage of that beat. The first small wave, called the P wave, reflects the upper chambers being activated. The tall central spike, called the QRS, reflects the contraction of the ventricles. The rounded wave that follows, the T wave, reflects those chambers electrically resetting before the next beat.

Because RBBB delays the signal to one ventricle, the two chambers no longer squeeze in perfect unison. The QRS spike, which is normally narrow and sharp, becomes wider and often develops a second bump, giving it a distinctive shape that a cardiologist recognises instantly.

Normal beat

P QRS T

The QRS spike is narrow and sharp. Both ventricles are activated almost together.

Right bundle branch block

P QRS T

The QRS is wider and carries a second bump. This is the delayed right ventricle catching up.

How to read this: the spike in the middle, the QRS, is the part to watch. A normal one is narrow and sharp. In RBBB it is wider and usually has a notch, like an M shape, because the right side of the heart is activated a beat behind the left. The small waves either side are not the focus here.

Why Does a Right Bundle Branch Block Happen?

There are many reasons, and they sit on a wide spectrum from completely benign to clinically important.

A normal variant

In many healthy people, RBBB is simply how their wiring is built. It can be present for life, cause no symptoms, and never lead to any trouble.

Age and the wiring itself

The conduction fibres can slow gradually with age, in the same way other tissues change over time. This is why RBBB becomes more common in later decades.

Strain on the right heart

Conditions that make the right side of the heart work harder, such as some lung conditions, can be associated with RBBB. Here the block is a signpost, not the problem itself.

Heart muscle conditions

Some conditions affecting the heart muscle or its valves can disturb the conduction system and produce RBBB along the way.

After a heart procedure

RBBB can appear after certain cardiac procedures or surgery. When expected, it is usually monitored rather than treated, and most people do well.

A sign during a heart attack

A brand new RBBB that appears during chest pain can be an important warning sign. This is the context that needs urgent assessment, not a routine finding.

The Question That Really Matters: Is It New?

This is the single most useful thing to understand about a right bundle branch block. The pattern itself tells a cardiologist relatively little until it is placed in context, and the most important piece of that context is whether the block is new or longstanding.

A right bundle branch block that has been present on previous ECGs for years, in someone who feels well, is reassuring. It is part of that person’s normal electrical signature. Research consistently shows that isolated RBBB in people without other heart disease carries an excellent outlook.

A right bundle branch block that has appeared for the first time, particularly alongside symptoms such as chest pain, breathlessness, or fainting, is a different matter. Here the new block may be a clue that something is happening in the heart right now, and it deserves prompt evaluation. This is why your cardiologist will often be very interested in finding an old ECG to compare against.

RBBB and LBBB Are Not the Same Story

It is natural to assume that a block on the right and a block on the left are mirror images of each other, equally significant. In practice, they tend to carry different weight.

A left bundle branch block more often prompts a closer look at the heart muscle and its pumping function, because the left ventricle is the heart’s main pump. An isolated right bundle branch block, by contrast, is more frequently a benign finding in an otherwise healthy person.

This is a generalisation rather than a rule, and the context still governs everything. But it helps explain why a patient might be told their RBBB is nothing to worry about while a friend with an LBBB was sent for more tests.

Will I Have Symptoms?

Most people with a right bundle branch block have no symptoms from it whatsoever. They feel completely normal, and the finding is picked up by chance on an ECG done for an unrelated reason, such as a routine check, a pre-operative assessment, or an insurance examination.

Because RBBB itself rarely causes symptoms, any symptoms that are present, such as breathlessness, palpitations, or fainting, usually point to whatever underlying condition is present rather than to the block on its own. That is part of why your cardiologist treats the symptoms and the whole clinical picture, not the line on the ECG report.

What Happens Next, and What Tests Might Be Done

If an isolated RBBB is found and you feel well, often the answer is simply that nothing further is needed beyond noting it on your record. Knowing it is there is valuable in itself, because it gives every future ECG a baseline to compare against.

When the context suggests a closer look is worthwhile, your cardiologist may arrange an echocardiogram, an ultrasound scan that shows the heart’s structure and how well it is pumping. This helps confirm whether the heart muscle and valves are normal. Depending on the situation, blood tests or a period of heart rhythm monitoring may also be suggested.

The point of these tests is not the block itself, which generally cannot and need not be reversed. It is to make sure there is nothing else going on that the RBBB might be pointing to.

When RBBB Sits Alongside Other Findings

One situation deserves a mention because it changes the picture. Sometimes RBBB appears on an ECG together with other conduction delays. When the heart’s electrical pathways show several areas of slowing at once, cardiologists pay closer attention, because the wiring is showing wear in more than one place.

In a small number of people, particularly those who also have symptoms such as fainting, this combination may eventually lead to a conversation about a pacemaker. This is the exception rather than the rule, and it applies to a minority of cases. The great majority of people with a simple, isolated RBBB never approach this territory.

Heart Matters Resource

When in Doubt, Get Checked Out

A new finding on an ECG, or one that comes with chest pain, breathlessness, or fainting, is always worth discussing promptly with your GP or cardiologist rather than worrying about alone.

Read: When in Doubt, Get Checked Out →

Conclusion

A right bundle branch block is an electrical finding, not a blocked artery, and for most people who carry one it is a harmless quirk of their heart’s wiring that will never cause a problem. The word block makes it sound far more alarming than it usually is.

What turns a routine finding into one worth investigating is context: whether it is new, whether it comes with symptoms, and whether it sits alongside other changes. If your ECG shows a right bundle branch block and you feel well, the most likely explanation is the most reassuring one. If it is new or you have symptoms, it is worth discussing with your cardiologist promptly, who can place that single line on the report into the bigger picture of your heart.

Related Reading

Patent Foramen Ovale (PFO): What the “Hole in the Heart” Finding Really Means

heartmatters.com 2026 03 31T224853.699
Key Points

  • A patent foramen ovale (PFO) is a small opening between the two upper chambers of the heart, present in roughly one in four adults, that simply did not seal after birth the way it usually does.
  • The vast majority of PFOs cause no symptoms and are found by chance. For most people, a PFO needs no treatment at all.
  • In a smaller group of patients, particularly those who have had a cryptogenic stroke (a stroke with no identified cause), a PFO may be the route by which a small clot crossed from the right to the left side of the heart and travelled to the brain.
  • In selected patients after a cryptogenic stroke, PFO closure (a minimally invasive catheter procedure) lowers the risk of a further stroke and is now supported by strong trial evidence.
  • Migraine with aura has a well-recognised association with PFO, though the relationship is complex, and closing a PFO for migraine alone is not currently standard practice.

A patent foramen ovale is one of those findings that can sound alarming when it is first mentioned. A hole in the heart, discovered on an echocardiogram, is not a phrase anyone wants to hear. And yet for most people who have one, it is entirely inconsequential. It requires no treatment, no monitoring, no change to how you live, and nothing you need to act on.

The reassurance I give most patients with a PFO is simple. You have a structural variation that around one in four adults share. In the vast majority of cases it is a finding rather than a diagnosis, something noted and filed, not something that needs managing.

Where it does become clinically relevant, mainly in the setting of an unexplained stroke in a younger person, is a separate and important conversation. But that conversation starts from a very different clinical picture than an incidental echo finding in someone who is otherwise well.

What Is a PFO?

Normal Circulation Before Birth

Before birth, the lungs are not yet doing their job. Rather than breathing, the baby receives oxygen-rich blood from the placenta. To bypass the lungs while they are still at rest, the circulation of every developing baby includes a small opening between the two upper chambers of the heart, called the foramen ovale. Blood passes straight through it from the right side to the left, skipping the lungs entirely.

At birth, the first breath opens the lungs, blood flow through them rises sharply, and the pressure in the left upper chamber climbs above that of the right. This change in pressure presses a small flap of tissue against the opening and seals it. In most people this seal becomes permanent over the first months of life, as the two layers of tissue gradually fuse.

What is a Patent Foramen Ovale?
A small unsealed opening in the wall between the upper chambers of the heart

Heart diagram showing Patent Foramen Ovale

Patent Foramen Ovale
An unsealed flap between the upper chambers, present in about 1 in 4 adults

~25%
of adults have a PFO, and most never know

Echo
Usually found by chance on an echocardiogram

Closure
Considered in selected stroke patients

heartmatters.com, patient education

When It Doesn’t Close

In around 25 to 27% of adults, roughly one in four, this fusion does not fully happen. The flap stays unsealed, leaving a potential channel between the two upper chambers that can open at moments of raised pressure on the right side of the heart, such as straining, coughing, or bearing down. This is a patent foramen ovale.

It is not a defect in the usual sense of the word. The heart formed normally, and the closure process simply did not finish. It causes no structural problem, no pressure abnormality, and no effect on how the heart works in the great majority of people who have one.

How Is a PFO Found?

Most PFOs are discovered by chance, on an echocardiogram done for another reason, such as looking into palpitations, a murmur, or as part of a stroke assessment. On a standard echocardiogram a PFO can be hard to see directly. A bubble study, in which a small amount of agitated saline is injected into a vein while you gently bear down, shows the PFO by revealing tiny bubbles crossing from the right chamber to the left. A transoesophageal echocardiogram gives the most detailed picture of a PFO’s size and shape.

Does It Actually Matter? The Context Question

The Incidental PFO, by Far the Most Common Situation

An incidental PFO, found in someone who has not had a stroke, has no neurological symptoms, and is otherwise well, needs no treatment. No blood thinners, no antiplatelet medicine beyond anything already needed for another reason, no closure procedure, and no restriction on activities including diving in most cases (high-altitude diving is a more nuanced discussion worth having with your cardiologist).

The most important thing I tell patients in this situation is that the finding does not change your risk in any way that matters clinically. One in four adults has one, and most go their whole lives without ever knowing.

PFO and Cryptogenic Stroke, the Association That Matters

About 30% of ischaemic strokes have no clear cause even after thorough investigation. These are called cryptogenic strokes. In younger patients who have had a cryptogenic stroke, a PFO is found more often than chance alone would explain, which suggests that in these individuals the PFO may have been the route through which the stroke happened.

The likely mechanism is called paradoxical embolism. A small clot forms in the venous system, often in the leg veins, travels to the right side of the heart, and crosses through the PFO into the left side at a moment of raised pressure, from where it can travel to the brain. This can happen without any obvious sign of a deep vein clot beforehand.

When a brain scan shows several small areas of stroke in different regions, suggesting clots arriving from a single source, a PFO assessment becomes particularly important. This is one reason prolonged heart monitoring for atrial fibrillation often goes hand in hand with a PFO assessment after a cryptogenic stroke. Both conditions can produce a similar pattern of stroke and need to be carefully told apart.

Three landmark randomised trials (RESPECT, CLOSE, and REDUCE) showed that closing a PFO in carefully selected patients after a cryptogenic stroke significantly lowers the risk of another stroke compared with antiplatelet medicine alone. This evidence has made PFO closure a standard recommendation for suitable patients after a cryptogenic stroke, typically those under 60 with a sizeable PFO and no other identified cause for the stroke.

Migraine With Aura

There is a well-documented link between PFO and migraine with aura. A PFO is more common in people who have migraine with aura than in the general population, and some people report fewer migraines after a PFO is closed. However, the trial evidence for closing a PFO specifically to treat migraine is mixed, and closure is not currently recommended for migraine with aura in someone who has not had a stroke. This remains an area of active research, and it is a reasonable thing to ask your cardiologist about if it affects you.

What PFO Closure Involves

PFO closure is a catheter-based procedure, with no open heart surgery involved. A thin tube is passed through a vein in the groin and guided up into the right upper chamber of the heart. With the help of echocardiography and X-ray guidance, a small device shaped like two discs is positioned across the opening, with one disc resting on each side of the wall. Over the following months, the body’s own tissue grows over the device and seals the opening permanently.

The procedure usually takes 30 to 60 minutes under sedation or light general anaesthesia, and most people go home the next day. Antiplatelet medicine is taken for a period afterwards, typically about six months, while the device becomes covered by the heart’s own lining. The long-term results are excellent, and device-related complications are very uncommon.

1 in 4
adults has a patent foramen ovale, making it one of the most common structural variations of the heart. For the great majority it is entirely harmless and needs no treatment.
American Heart Association

Clinical Situation Typical Approach Why
Incidental PFO, no stroke, no symptoms Reassurance, no treatment needed One in four adults has one; the risks of closing it outweigh any benefit
Cryptogenic stroke, under 60, no other cause found PFO closure, strongly considered Trial evidence shows a meaningful drop in further strokes
Cryptogenic stroke, over 60 Individualised, blood thinners often preferred Other possible mechanisms more likely; benefit of closure less clear
Migraine with aura, no stroke history No closure, not standard practice Evidence not yet sufficient; trials ongoing
Decompression illness in divers Individualised assessment A careful, case-by-case discussion with a specialist

The most important conversation I have with patients who have a PFO is about context. The finding can be the same in two people. The significance can be entirely different. Context is everything.

Prof. Peter Barlis, Interventional Cardiologist

Questions Worth Asking at Your Next Appointment

  • My PFO was found by chance. Do I need any treatment, monitoring, or change to how I live?
  • I have had a stroke with no identified cause. Is my PFO likely to have been involved, and could I be a candidate for closure?
  • What do the size and shape of my PFO mean for my risk? Are all PFOs the same?
  • I dive recreationally. Does having a PFO change my risk, and should I adjust how I dive?
  • I have migraine with aura. Is there a link with my PFO, and is closure something I should consider?

Heart Matters Resource

When in Doubt, Get Checked Out

If you have been told you have a PFO and are unsure what it means for you, particularly if you have had a neurological event, a cardiology review to put the finding in context is the right next step.

Read: When in Doubt, Get Checked Out →

Conclusion

A patent foramen ovale is perhaps the cardiac finding that most needs to be put in context. In the great majority of people who have one, and a quarter of all adults do, it is entirely harmless, needs no intervention, and is nothing you need to act on.

In a carefully defined group of patients, those who have had a cryptogenic stroke at a younger age with no other identifiable cause, closing a PFO is a worthwhile step with strong evidence behind it. The procedure is safe, effective, and minimally invasive.

The key, in the end, is context. The very same finding can mean completely different things depending on the clinical picture in which it is discovered. Your cardiologist’s role is to place that finding in its proper frame, and where that frame is reassurance, the reassurance should be complete and confident.

Related Reading

Understanding Dizziness: A Cardiologist’s Guide

heartmatters.com 71

Dizziness means something different to almost everyone who uses the word, and that description is what points to the cause. A cardiologist explains the four types, what causes each, and when your heart is involved.

What is a Muscle Bridge?

Muscle bridge
Key Points

  • A myocardial bridge, often just called a muscle bridge, is a common and usually harmless variant present from birth, where a short stretch of a coronary artery dips down and runs through the heart muscle instead of sitting on the surface. Most people who have one will never know and never need treatment.
  • In a minority of people, a bridge can cause genuine symptoms, most often chest pain or tightness brought on by exertion or stress. These patients deserve to be taken seriously rather than reassured by default.
  • A standard angiogram often underestimates a bridge. Confirming whether a bridge is actually causing symptoms usually needs more detailed assessment, including intravascular ultrasound and specialised stress testing.
  • Most symptomatic bridges are managed well with medication, usually beta-blockers or calcium channel blockers. A small, carefully selected group with severe, persistent symptoms may benefit from an operation called surgical unroofing.
  • A large 2026 study from Stanford, published in the European Heart Journal, found that for this selected group, surgical unroofing produced lasting relief from angina five years later, with a low complication rate.

You have a muscle bridge. Many people hear that sentence for the first time lying on an angiogram table, nod along, and leave none the wiser. It is rarely explained in much depth, partly because for most people it carries no consequence at all, and partly because the few it does affect need a longer conversation than a results appointment allows.

A myocardial bridge is one of the most common variations in human heart anatomy. The overwhelming majority cause no symptoms, need no treatment, and carry no meaningful risk. For a smaller group of people, though, a bridge can be a real and treatable cause of angina, and telling those two groups apart is what good assessment is for.

This article explains what a muscle bridge actually is, why most are harmless, how the troublesome minority are identified, and what the newest evidence says about treating them.

What a Myocardial Bridge Actually Is

The coronary arteries, the vessels that supply blood to the heart muscle itself, normally run along the outer surface of the heart, sitting on top like rivers on a landscape. A myocardial bridge is a stretch where one of these arteries takes a short detour and tunnels down through the heart muscle before surfacing again on the other side.

The band of muscle lying over the tunnelled segment is the “bridge.” The buried portion of artery is sometimes called the tunnelled segment. It is present from birth, which means a bridge is a variation in how the heart formed rather than something that develops, wears in, or is caused by lifestyle. Around 97% of bridges occur in the same vessel, the left anterior descending artery, which runs down the front of the heart.

Diagram comparing a normal coronary artery running along the heart surface with a myocardial bridge, where the artery dips down through the heart muscle and is squeezed with each heartbeat.
In a normal artery, blood flows freely along the heart’s surface. In a myocardial bridge, the artery dips down and runs through the heart muscle for a stretch, and the overlying muscle squeezes that segment with each heartbeat.

The reason a bridge can matter comes down to mechanics. Every time the heart contracts, the muscle squeezes. If a segment of artery is buried inside that muscle, it gets squeezed too, narrowing with each beat. The heart does most of its own blood supply during the relaxation phase between beats, and in a bridge the squeeze can linger into that phase, slightly delaying the artery from springing back open. When the heart is calm and beating slowly, this rarely matters. When the heart beats fast, during exertion, stress, or strong emotion, the relaxation phase shortens, and the lingering squeeze has proportionally more effect. This is why bridge symptoms, when they occur, are so often tied to exertion.

Why Most Bridges Cause No Trouble

The single most important thing to understand about muscle bridges is how common they are, and how rarely they cause problems. The numbers vary enormously depending on how you look for them, which is itself revealing.

Up to 1 in 4
people may have a myocardial bridge when hearts are examined closely, yet only a small fraction ever experience symptoms from it.
Imaging and autopsy studies, summarised in European Heart Journal, 2026

On a standard coronary angiogram, bridges turn up in only a few percent of people. On detailed imaging such as CT coronary angiography, the figure is much higher, and when hearts are examined directly the prevalence rises further still, into the range of one in five to one in four. The gap between these numbers tells the story: most bridges are shallow, short, and functionally silent. They are found incidentally, if they are found at all, and they sit quietly for a lifetime.

So if you have been told you have a bridge and you have no symptoms, the most likely situation by far is that the bridge is an anatomical footnote rather than a problem. It does not need fixing, and in most cases it does not need anything beyond the awareness that it is there.

When a Bridge Does Cause Symptoms

A minority of people with a bridge experience real symptoms, most commonly chest pain or tightness that comes on with exertion or stress and eases with rest. Some describe breathlessness, and some report that episodes last noticeably longer than a typical bout of exertional chest pain. Whether a particular bridge causes symptoms depends on several features working together.

Length of the bridge

A longer tunnelled segment means more of the artery is subject to the muscle’s squeeze with each beat. Longer bridges are more likely to be functionally significant than short ones.

Depth of the tunnel

How deeply the artery is buried in the muscle matters. A deeper bridge is compressed more forcefully, so deeper bridges tend to have a greater effect on blood flow than superficial ones.

Heart rate and exertion

A fast heart rate shortens the relaxation phase when the artery would normally recover. This is why bridge symptoms typically appear during exercise, stress, or strong emotion rather than at rest.

Coronary spasm

Bridges frequently sit alongside a tendency for the artery to spasm, or tighten suddenly. Spasm can drive symptoms independently of the bridge itself and changes how the condition is treated.

Endothelial function

The artery lining near a bridge is often under abnormal mechanical stress, which can impair its ability to relax and widen on demand. This contributes to symptoms in many bridge patients.

Plaque just upstream

The disturbed blood flow around a bridge tends to encourage fatty plaque to build up in the artery just before it, which can add its own contribution to symptoms and risk.

Because several of these factors often coexist, a bridge that looks modest on a picture can still be the source of meaningful symptoms, and a bridge that looks dramatic can sit silent. Anatomy alone does not settle the question. This is the central difficulty in managing bridges, and it shapes everything about how they are investigated.

Why a Bridge Is Harder to Diagnose Than It Sounds

It would be reasonable to assume that if a bridge shows up on an angiogram, the picture tells the whole story. In practice it rarely does. A standard coronary angiogram is good at finding flow-limiting blockages, but it has low sensitivity for bridges and tells you little about how deep a bridge is, how long it is, or whether it is actually responsible for a person’s symptoms.

When symptoms and anatomy do not obviously line up, cardiologists turn to more detailed assessment. Intravascular ultrasound, a tiny ultrasound probe threaded into the artery, is considered the most reliable way to confirm a bridge and measure its length and depth precisely. To judge whether the bridge is functionally significant, meaning it genuinely restricts flow under stress, specialised measurements are taken while the heart is pushed to work harder with a medication called dobutamine. Standard pressure-wire measurements used for ordinary blockages are not adequate for assessing a bridge, which is part of why bridge assessment is a specialised undertaking.

A particular pattern on a stress echocardiogram, a transient buckling in one part of the heart wall with the tip of the heart spared, can also raise suspicion of a bridge non-invasively. The broader point for patients is that confirming a bridge as the cause of symptoms is a deliberate, layered process, not a single glance at an angiogram.

Finding a bridge and proving that the bridge is the cause of someone’s pain are two very different things. Most bridges are bystanders. The clinical skill lies in identifying the minority that are genuinely to blame, and treating that group properly without over-treating everyone else.

Heart Matters editorial

How Symptomatic Bridges Are Treated

Medication comes first

For the large majority of people whose bridge does cause symptoms, medication is the first and usually the only treatment needed. The two mainstays are beta-blockers and calcium channel blockers. Both work in part by slowing the heart and easing the force of each contraction, which lengthens the relaxation phase and reduces the squeezing effect on the bridged artery. They can be very effective, and many people are managed comfortably on them for years.

One counter-intuitive point is worth knowing. Nitrates, which are a standard reliever for ordinary angina, are often used with caution in bridge patients and can sometimes make symptoms worse rather than better. If you have a bridge and find that a nitrate spray does not help your chest pain in the way you would expect, or seems to aggravate it, that is worth mentioning to your cardiologist rather than dismissing.

When an operation is considered

A small, carefully selected group of patients continue to have severe, life-limiting symptoms despite the best medication can offer, and have a bridge that has been confirmed as genuinely significant on detailed testing. For this group, a surgical option exists. The preferred operation is called surgical unroofing, in which the surgeon carefully divides the band of muscle lying over the tunnelled artery, freeing the vessel to return to the surface where it belongs.

Two other approaches, placing a stent inside the bridged segment or performing a coronary artery bypass, have generally proved less satisfactory for bridges specifically, which is why unroofing has become the favoured operation in suitable patients. It is important to stress that this is a treatment for a minority within a minority. The vast majority of people with a bridge will never come close to needing it.

What the Latest Research Shows

Until recently, a fair question about unroofing was whether its benefits lasted. Earlier work had shown good results at six months, but long-term evidence was thin. A 2026 study from Stanford University, published in the European Heart Journal, has now provided the most substantial answer to date.

The researchers followed 218 patients who had undergone surgical unroofing of a significant bridge in the left anterior descending artery after medication had failed to control severe angina. The patients were relatively young, with a median age of 49, and around 60% were women. They were followed for a median of five years.

Nearly 9 in 10
patients reported a meaningful, lasting improvement in their angina five years after surgical unroofing, with episodes typically falling from weekly to monthly.
Pargaonkar et al., European Heart Journal, 2026

Across every measure of symptoms and quality of life, patients reported significant and durable improvement, and most needed fewer anti-anginal medications afterwards than before. When the surgical patients were compared with a closely matched group who had a similarly significant bridge but were managed with medication alone, the surgical group showed greater relief from physical limitation and from the frequency of their angina. Importantly, the operation proved safe in experienced hands, with a low rate of major cardiac events over the follow-up period and none of those events attributed to the surgery itself.

The practical message for patients is measured rather than dramatic. For the specific, carefully selected group with a confirmed significant bridge and severe symptoms that medication cannot control, surgical unroofing is now backed by solid long-term evidence as a worthwhile option. It is not a treatment for an incidental finding, and it is not a first step. It is a well-supported last resort for those who genuinely need it.

The Bridge Is Rarely the Whole Story

One of the most useful insights from the recent research is that a bridge often travels with company. In the Stanford group, who were of course a highly selected population with difficult symptoms, almost all had a small build-up of fatty plaque in the artery just upstream of the bridge, and the great majority showed evidence of coronary spasm or of an artery lining that did not relax normally on testing.

This matters for two reasons. First, it explains why a few patients still have some symptoms even after a technically successful unroofing: if spasm or lining dysfunction was contributing, removing the muscle band does not address that part of the problem, and ongoing medication may still be needed. Second, the tendency for plaque to form just before a bridge is part of why attention to general cardiovascular risk, including the standard modifiable risk factors, remains relevant even when the headline issue is a structural one present from birth.

Heart Matters Resource

When in Doubt, Get Checked Out

If you have been told you have a muscle bridge and you are experiencing chest pain, breathlessness, or symptoms on exertion, those symptoms are worth a proper conversation with your cardiologist rather than assuming the bridge is harmless.

Read: When in Doubt, Get Checked Out →

Conclusion

A myocardial bridge is, for most people, exactly what it usually sounds like when a cardiologist mentions it in passing: a common quirk of heart anatomy that asks nothing of you and changes nothing about your life. If you have one and no symptoms, that is almost certainly where the story ends.

For the minority who do have symptoms, a bridge is a real and treatable condition. The key is careful assessment to confirm whether the bridge is genuinely the cause, sensible use of medication for the many, and a well-evidenced surgical option held in reserve for the few who need it. If you have a bridge and symptoms that affect your daily life, the right next step is not to worry alone but to have it properly evaluated, because the difference between a harmless bystander and a treatable problem is exactly the kind of question modern cardiology is now well equipped to answer.

Related Reading

White Coat Hypertension: When Your BP Spikes at the Doctor’s

Doctor measuring blood pressure of patient. white coat hypertension
Key Points

  • White coat hypertension is when your blood pressure reads high in the clinic but sits in the normal range during ordinary daily life. It is common, affecting up to one in three people whose office readings are raised.
  • It is caused by a stress response to the medical setting itself, not by a fault in your heart or blood vessels. The reading is real, but it does not reflect your usual blood pressure.
  • The only reliable way to confirm it is to measure blood pressure away from the clinic, using either a 24-hour ambulatory monitor or a structured week of home readings.
  • White coat hypertension is not always harmless. Some people go on to develop sustained high blood pressure, so ongoing monitoring matters even when no medication is started.
  • Its mirror image, masked hypertension, is the more dangerous pattern: normal in the clinic, high at home, and easy to miss without out-of-office measurement.

The cuff tightens, the nurse watches the dial, and the number that appears is higher than anything you ever see at home. It happens every visit. You feel perfectly well, your home readings are reassuring, and yet the clinic keeps telling you your blood pressure is up. If this sounds familiar, you may have white coat hypertension.

It is one of the most common and most misunderstood findings in everyday medicine. The reading on the machine is not wrong. Your blood pressure really did rise in that moment. The question is whether that rise reflects how your heart and arteries behave during the other 23 hours of the day, when no one is watching.

Getting that question right matters. Treat white coat hypertension as though it were sustained high blood pressure and a person can end up on medication they do not need. Dismiss it entirely and you can miss the early warning that genuine hypertension is developing. The path between those two errors runs through one simple idea: measure blood pressure where life actually happens.

What White Coat Hypertension Actually Is

White coat hypertension describes a specific pattern. Blood pressure measured in a clinic or surgery is in the hypertensive range, while blood pressure measured away from the clinic is normal. The term comes from the white coats traditionally worn by doctors, though the effect has far more to do with the setting than the clothing.

The mechanism is a stress response. Being assessed by a health professional, sitting in an unfamiliar room, anticipating bad news, or simply rushing to make the appointment can all trigger a brief surge in heart rate and blood pressure. This is the same fight-or-flight system that sharpens your senses before a job interview. In most people it settles within minutes of leaving. For some, it switches on reliably the moment a cuff appears.

This is different from anxiety as a diagnosis. Many people with white coat hypertension do not feel anxious at all. The body responds to the clinical context automatically, below the level of conscious worry, which is part of why telling someone to relax so rarely lowers the number.

If the two numbers in a blood pressure reading have always been a little mysterious, this short explainer walks through what systolic and diastolic actually mean.

Watch · Heart Matters

Systolic and diastolic, explained. A plain-English guide to what the two numbers in a blood pressure reading actually mean.

How Common Is It?

White coat hypertension is far from rare. Across large studies, when people with raised office readings are checked properly away from the clinic, a substantial proportion turn out to have normal everyday blood pressure.

15 to 30%
of people with high readings in the clinic are found to have white coat hypertension once their blood pressure is measured during normal daily life
International blood pressure registries

The effect tends to be more pronounced in older adults and in people who have been told for years that they have high blood pressure. It can even appear in people already taking blood pressure medication, where it can make treatment look as though it is failing when in fact the everyday numbers are well controlled.

Why It Is Easy to Get Wrong

The trouble with a clinic reading is that it captures a single, atypical moment. A few minutes in a medical room, often after sitting in a waiting area or hurrying through traffic, is not a fair sample of a whole day. Yet for decades this single snapshot was the basis for diagnosing high blood pressure.

When the diagnosis rests on office readings alone, two opposite mistakes become possible. The first is overdiagnosis: labelling someone hypertensive, and starting lifelong treatment, when their true blood pressure is fine. The second is the reverse problem, where genuinely high blood pressure outside the clinic goes undetected because the office reading happens to look acceptable.

Modern guidelines now treat measurement outside the clinic as essential rather than optional. The same principle underpins our advice on monitoring your blood pressure at home: the numbers that matter most are the ones gathered during ordinary life, not in a single moment of clinical stress.

White Coat Versus Masked Hypertension

White coat hypertension has a mirror image, and understanding both makes the whole picture clearer. They are opposite patterns, and they carry very different levels of risk.

White Coat Hypertension

High in the clinic, normal at home. Risk is generally lower than sustained high blood pressure, but it can progress over time, so it needs watching rather than ignoring.

Masked Hypertension

Normal in the clinic, high at home. This is the more concerning pattern, because the raised blood pressure quietly damages arteries and the heart while routine checks look reassuring.

Masked hypertension is the more dangerous of the two precisely because it hides. A person feels well, their clinic readings look fine, and no one suspects a problem, while their blood pressure runs high during work, sleep, and daily activity. This is part of why a single normal reading in the surgery is no longer considered enough to rule high blood pressure out.

How It Is Diagnosed

Confirming white coat hypertension means comparing clinic readings with readings taken during normal life. There are two reliable ways to do this, and your doctor may use either or both.

Ambulatory monitoring

A small device worn for 24 hours takes automatic readings during the day and overnight. It gives the fullest picture, including how blood pressure behaves during sleep.

Home monitoring

A validated upper-arm monitor used at set times over about a week. Readings taken morning and evening, while seated and rested, build a reliable everyday average.

The thresholds differ slightly between settings, which surprises many people. Clinic readings use one cut-off for diagnosing high blood pressure, while home and daytime ambulatory averages use a slightly lower one. This is normal and expected, because blood pressure is genuinely a little lower in relaxed, familiar surroundings.

For a closer look at why the clinic setting itself nudges your reading upward, this video explains what is happening in the body during that moment.

Watch · Heart Matters

The white coat effect, up close. Why the clinic setting itself can push your reading up, and what is happening in the body.

A blood pressure reading is a moment, not a verdict. The honest answer almost always comes from measuring it where the patient actually lives their life.

Prof. Peter Barlis, Interventional Cardiologist

Does It Need Treatment?

For true white coat hypertension, where everyday blood pressure is genuinely normal, medication is often unnecessary. The reading that rises only in the clinic does not, on its own, justify lifelong tablets. What it does justify is ongoing attention.

That is the key nuance. White coat hypertension sits somewhere between normal blood pressure and sustained high blood pressure in terms of long-term risk. A meaningful number of people with it will develop genuine hypertension within a few years. So the sensible approach is regular review, repeat out-of-office measurement, and attention to the everyday habits that keep blood pressure healthy.

Where lifestyle and risk factors are concerned, the same fundamentals apply as for anyone protecting their heart: maintaining a healthy weight, limiting salt and alcohol, staying physically active, and not smoking. Even something as accessible as regular walking contributes to keeping blood pressure in a healthy range over time.

When blood pressure is genuinely high outside the clinic, treatment follows the usual path. The medicines most often used include ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers, chosen to suit the individual. The decision to start, change, or hold any blood pressure medicine is one only your doctor or cardiologist can make for you, based on your full picture rather than a single number.

Getting an Accurate Reading at Home

If you are monitoring your own blood pressure, a few simple habits make the readings far more trustworthy. Small details in technique can shift a result by enough to change a diagnosis.

Sit and settle first

Rest quietly for five minutes before measuring. Sit with your back supported, feet flat on the floor, and legs uncrossed.

Support your arm

Rest your arm on a table so the cuff sits at heart height. An unsupported or dangling arm can push the reading up noticeably.

Measure twice, same times

Take two readings a minute apart, morning and evening, for several days. Record them all rather than picking the lowest.

Avoid caffeine, exercise, and smoking for at least 30 minutes beforehand, and empty your bladder first, as a full bladder can raise the reading. Use a validated upper-arm monitor rather than a wrist device, and bring your log to your next appointment so the pattern, not just a single number, guides the conversation.

Heart Matters Resource

When in Doubt, Get Checked Out

If your clinic and home readings keep telling you different stories, that is worth investigating properly rather than guessing. A short period of out-of-office monitoring can settle the question for good.

Read: When in Doubt, Get Checked Out →

Conclusion

White coat hypertension is a reminder that a blood pressure reading is a measurement of a moment, not a final judgement on your heart. The number that climbs in the clinic is genuine, but it tells only part of the story. The fuller answer comes from seeing how your blood pressure behaves across an ordinary day.

If your clinic readings have been high but you suspect they do not reflect your everyday self, the practical step is straightforward: ask about ambulatory or home monitoring, measure carefully, and review the pattern with your doctor. Whether the outcome is reassurance or the early detection of genuine high blood pressure, you come away knowing your real numbers, which is exactly where good heart care begins.

Related Reading

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