Cardiac Tests & Procedures Explained

To Fast or Not to Fast Before a Blood Test?

September 30, 2026

Key Points

Most heart-related blood tests do not require fasting. Fasting matters most for the fasting glucose and glucose tolerance tests, and is often recommended for cholesterol tests, particularly when triglycerides are measured.
Fasting is often recommended before a cholesterol panel, because meals raise triglycerides and fasting keeps results consistent between tests. A normal meal changes LDL and HDL cholesterol only slightly, so a non-fasting sample is acceptable for many routine checks.
The HbA1c test, which reflects average blood glucose over the previous two to three months, does not require fasting.
When fasting is needed, it usually means no food or drinks other than water for 8 to 12 hours. Exact instructions vary between laboratories.
Fasting can cause low blood sugar in people taking insulin or some diabetes tablets, which is why they are usually given specific instructions before a fasting test.

Few instructions cause as much confusion as “fast before your blood test.” Does black coffee count? What about morning tablets? And why does one cholesterol test come with fasting instructions while the next does not?

The short answer is that fasting matters a great deal for a few tests, matters in particular situations for cholesterol, and makes very little difference for most others. Knowing which is which can spare an uncomfortable morning and, for some people, avoid a genuine risk.

Why Food Affects Some Blood Tests

After a meal, sugars and fats from food pass into the bloodstream. For a few hours, the levels of some substances in the blood rise, while others barely change.

Glucose (blood sugar) and triglycerides are the two most affected. A test designed to measure a “resting” level of either can be misleading if taken soon after eating. Most other routine blood tests are affected so little by a normal meal that fasting makes no practical difference.

Which Heart-Related Tests Need Fasting?

The table below shows how fasting requirements typically apply to common blood tests in heart care. Individual laboratories may set their own requirements, and the instructions given with a test request take priority.

Test	Fasting Usually Needed?	Why
Fasting glucose	Yes	Food raises blood glucose for several hours
Glucose tolerance test	Yes	Measures the response to a standard glucose drink from a fasting start
HbA1c	No	Reflects average glucose over months, not today’s meals
Cholesterol panel, including triglycerides	Often recommended	Meals raise triglycerides, and fasting keeps results comparable from one test to the next
Iron studies	Sometimes	Some laboratories prefer a morning sample, as iron levels vary
Troponin and BNP	No	Often urgent, and not meaningfully affected by food
INR, kidney function, hs-CRP	Usually not	Routine checks are generally done without fasting

Tests used to assess chest pain or heart strain, such as troponin and BNP, are taken whenever they are needed, often in an emergency department. Fasting plays no part in them.

Routine monitoring tests, such as the INR used for people taking warfarin and the hs-CRP test, are generally done without fasting. For iron studies, used to check for iron deficiency, some laboratories prefer a morning sample because iron levels in the blood vary through the day.

Glucose Tests and Fasting

Blood glucose tests are where fasting matters most. They are used to check for diabetes and prediabetes, both important risk factors for heart disease.

Fasting glucose

A fasting glucose test measures blood sugar after a period without food. The American Diabetes Association defines fasting as no calorie intake for at least 8 hours. An overnight fast with a morning test is the usual arrangement.

Eating before this test can push the result into a range that looks like diabetes when it is not. That is why a fasting glucose result taken after breakfast cannot be interpreted in the usual way.

Glucose tolerance test

The oral glucose tolerance test shows how well the body clears sugar from the blood. After an overnight fast, a blood sample is taken, a standard drink containing 75 g of glucose is given, and a second sample is taken two hours later. The test takes a couple of hours in total and is commonly used in pregnancy.

HbA1c

The HbA1c test measures how much glucose has attached to red blood cells over the previous two to three months. Because it reflects a long-term average, a meal beforehand has no meaningful effect, and no fasting is needed.

HbA1c is reported in two ways around the world: as a percentage, or in millimoles per mole (mmol/mol). A result of 6.5% is the same as 48 mmol/mol.

Glucose results in both units

Glucose is reported in mmol/L in many countries and in mg/dL in others, including the United States. A result in mmol/L multiplied by 18 gives the value in mg/dL. The table shows the levels the American Diabetes Association uses to define diabetes.

Test	Fasting?	Diabetes Range (mmol/L)	Diabetes Range (mg/dL)
Fasting glucose	Yes	7.0 or higher	126 or higher
Glucose tolerance test (2 hours)	Yes	11.1 or higher	200 or higher
Random glucose, with symptoms	No	11.1 or higher	200 or higher

The range for prediabetes differs between organisations. The American Diabetes Association uses a fasting glucose of 5.6 to 6.9 mmol/L (100 to 125 mg/dL), while the World Health Organization uses 6.1 to 6.9 mmol/L (110 to 125 mg/dL). Unless a result is clearly abnormal, a diagnosis of diabetes is usually confirmed with a second test, and interpreting results is a matter for the requesting doctor.

Cholesterol Tests: When Fasting Helps

Cholesterol tests were traditionally done after fasting. A joint consensus statement from the European Atherosclerosis Society and the European Federation of Clinical Chemistry and Laboratory Medicine reviewed large studies comparing fasting and non-fasting results.

After normal meals, triglycerides rose by up to about 0.3 mmol/L (26 mg/dL), while total and LDL cholesterol fell by about 0.2 mmol/L (8 mg/dL). HDL cholesterol and lipoprotein(a) were not affected. Non-fasting results predicted heart disease risk just as well as fasting ones, so the statement recommends non-fasting samples for routine testing.

Why triglycerides are different

Triglycerides are the part of the cholesterol panel most affected by food. The average rise after a meal is small, but it can be much larger after a fatty meal, and in people with diabetes, excess abdominal weight, or already raised triglycerides.

This matters for LDL cholesterol too. In most laboratories, LDL is calculated from the other values, including triglycerides. The higher the triglyceride level, the less accurate that calculation becomes.

For these reasons, American guidelines state that a fasting sample is most helpful in several situations:

When triglycerides have been high before, particularly above 4.5 mmol/L (400 mg/dL).
When high triglycerides are being diagnosed or monitored.
When there is a family history of early heart disease or an inherited cholesterol disorder.
When checking how much risk remains for a person already on cholesterol-lowering treatment.

European guidance suggests a fasting repeat when a non-fasting triglyceride level is above 5 mmol/L (440 mg/dL). In everyday practice, many doctors request a fasting sample for cholesterol tests, particularly when triglycerides are part of the question. When a test request asks for fasting, that instruction is the one that applies.

I usually recommend fasting before a cholesterol test. I often request a full panel, including glucose and triglycerides, and fasting keeps results consistent, which makes monitoring over time more reliable.

Prof. Peter Barlis, Interventional Cardiologist

What Counts as Fasting?

Definitions vary. The American Diabetes Association uses at least 8 hours without calories, while European laboratory guidance recommends 12 hours. Water is permitted in both, and many laboratories encourage it, as good hydration can make blood easier to draw.

European laboratory guidance also advises against alcohol for 24 hours beforehand, and against coffee, tea, and smoking on the morning of the test. Chewing gum can affect some results too. Because practice differs between countries and laboratories, the instructions supplied with the test are the most reliable guide.

Medicines and Fasting

Advice about medicines on the morning of a fasting test varies. Most regular heart medicines are commonly taken as normal with water, but some laboratories and doctors ask for particular medicines to be delayed until after the sample. The requesting doctor or laboratory gives instructions for each person.

People with diabetes need particular care. Insulin and some diabetes tablets can cause low blood sugar when a meal is skipped, which can lead to shakiness, sweating, confusion, or fainting. For this reason, people taking these medicines are usually given specific instructions about timing their medicine and the test, and tests are often booked early in the morning.

Conclusion

Fasting matters for a small number of blood tests, chiefly the fasting glucose and glucose tolerance tests. For cholesterol tests, fasting is often recommended because it gives a clearer and more consistent triglyceride result, although a non-fasting sample is acceptable for many routine checks. For most other heart-related tests, including HbA1c, fasting makes little or no difference.

When fasting is required, the instructions that come with the test request are the best guide, and questions about medicines are worth raising with the requesting doctor or laboratory beforehand. A few minutes of clarification can prevent a wasted trip or an unreliable result.

Understanding Your Cholesterol Test: What Each Number Means

September 21, 2026

Key Points

A standard cholesterol test, often called a lipid profile, measures several different fats in the blood. LDL cholesterol is the number most closely linked to heart attack and stroke risk.
There is no single “normal” LDL level that suits everyone. The goal depends on each person’s overall cardiovascular risk, and a result flagged as normal on a lab report may still be above the goal for someone with heart disease.
Results are reported in one of two units depending on the country and laboratory: millimoles per litre (mmol/L) or milligrams per decilitre (mg/dL). The same result looks very different in each.
Lipoprotein(a) is the exception. Its two units, mg/dL and nmol/L, cannot be converted reliably, so the result is best read in the unit the laboratory used.
For most routine tests, fasting beforehand is not required.

A cholesterol result often arrives as a column of numbers, a few abbreviations, and perhaps an asterisk. What it rarely includes is an explanation. One figure may be flagged high, another low, and it is not always clear which matter most.

This guide explains what each part of a standard cholesterol test measures, how the two international units work, and why the right number for one person can be quite different from the right number for another.

Why Cholesterol Matters

Cholesterol is a waxy fat the body needs to build cells and make hormones. It travels in the blood inside particles called lipoproteins. Some of these particles can lodge in artery walls, where they build up over many years into the fatty plaque of atherosclerosis.

That plaque narrows arteries and can rupture, triggering a heart attack or stroke. The more of these particles in the blood, and the longer they are there, the greater the build-up. This is why cholesterol testing sits at the centre of heart disease prevention.

What a Cholesterol Test Measures

A standard lipid profile usually reports four or five values. Some laboratories add others, such as lipoprotein(a) or apolipoprotein B, when requested.

The numbers on a cholesterol report

LDL cholesterol

The main driver of plaque build-up. The number most treatment goals are based on.

HDL cholesterol

Carries cholesterol away from the arteries. Low levels are linked to higher risk.

Triglycerides

A different type of blood fat, influenced by diet, alcohol, weight, and diabetes.

Total cholesterol

All cholesterol combined. Useful for calculations, less useful on its own.

Non-HDL cholesterol

Total minus HDL. Captures all the particles that can form plaque.

Lipoprotein(a)

An inherited particle, usually measured once in a lifetime rather than routinely.

LDL cholesterol

LDL (low-density lipoprotein) cholesterol is the most important number on the report. Large genetic studies and clinical trials consistently show that lower LDL levels mean less plaque and fewer heart attacks and strokes. Most treatment decisions are built around it.

In many laboratories LDL is calculated from the other values rather than measured directly. The calculation is less accurate when triglycerides are very high or LDL is very low, which is why some laboratories measure it directly in those situations.

HDL cholesterol

HDL (high-density lipoprotein) cholesterol helps carry cholesterol away from artery walls. Low HDL levels are linked to higher cardiovascular risk. However, medicines that raise HDL have not, on their own, been shown to reduce heart attacks in trials, and HDL is not a treatment goal in major guidelines.

Triglycerides

Triglycerides are the body’s main store of fat. Levels are influenced by diet, alcohol, body weight, diabetes, and some medicines. Raised triglycerides add to cardiovascular risk, and very high levels can also inflame the pancreas.

Non-HDL cholesterol

Non-HDL cholesterol is total cholesterol minus HDL. It captures every type of particle that can contribute to plaque, not only LDL. Both European and American guidelines use it as a secondary goal, particularly for people with raised triglycerides or diabetes.

Two Units, One Result

Cholesterol results are reported in one of two units, depending on the country and the laboratory. Much of the world, including the UK, Canada, Australia, and New Zealand, uses millimoles per litre (mmol/L). The United States and a number of other countries use milligrams per decilitre (mg/dL).

The same blood sample gives very different-looking numbers in each unit. An LDL of 2.6 mmol/L is the same as 100 mg/dL. Knowing which unit a report uses is the first step in making sense of it, and the unit is usually printed beside each value.

For cholesterol values (total, LDL, HDL, and non-HDL), a result in mmol/L multiplied by about 38.7 gives the value in mg/dL. Triglycerides use a different factor, about 88.6, because they are a different molecule. Throughout this article, mmol/L is given first, with mg/dL in brackets.

Lipoprotein(a) is the exception

Lipoprotein(a), often written Lp(a), is reported either in mg/dL or in nanomoles per litre (nmol/L). Unlike cholesterol, there is no reliable way to convert between these units, because Lp(a) particles vary in size from person to person.

The guidelines themselves show the difficulty. European guidelines treat an Lp(a) above 50 mg/dL (105 nmol/L) as a risk-enhancing factor, while American guidelines treat 50 mg/dL (125 nmol/L) as the equivalent threshold. An Lp(a) result is therefore best read in the unit the laboratory reported, without converting it.

Why There Is No Single “Normal” Number

Laboratory reports usually print a reference range beside each result. This range describes typical values in the general population. It does not describe the right level for any particular person.

Guidelines set LDL goals according to overall cardiovascular risk. That risk takes into account age, blood pressure, smoking, diabetes, kidney function, family history, and whether heart or artery disease is already present. The higher the risk, the lower the LDL goal.

This is why an LDL of 2.5 mmol/L (97 mg/dL) might be flagged as normal on a report, yet sit well above the goal for someone who has had a heart attack. The table below shows the goals used in European guidelines. American guidelines use closely matching goals for most risk groups.

Risk Level	LDL Goal (mmol/L)	LDL Goal (mg/dL)
Very high	Below 1.4	Below 55
High	Below 1.8	Below 70
Moderate	Below 2.6	Below 100
Low	Below 3.0	Below 116

Most people who have had a heart attack, a stent, or a stroke fall into the very high risk group. European guidelines also recommend that people in the high and very high risk groups reduce their LDL by at least half from their starting level. Which risk group applies to an individual, and what their goal should be, is a judgement for their own doctor.

Preparing for the Test

For most routine cholesterol tests, fasting is not required. A meal before the test has only a small effect on most values, although triglycerides rise a little after eating. A fasting sample is sometimes requested when triglycerides are high or when an earlier result needs checking.

Cholesterol levels also vary naturally from one test to the next. An illness in the weeks before the test, a significant change in diet, or a change in medicines can all shift results. For this reason, doctors usually look at the trend across several tests rather than reacting to a single figure.

What Happens After the Result

When LDL is above a person’s goal, the first step is usually a look at overall risk and lifestyle. Diet plays a real but often modest role. Eating patterns rich in unsaturated fats and fibre help, and some foods affect blood cholesterol less than commonly assumed, as the evidence on eggs and cholesterol shows.

Where medicines are needed, statins are the foundation of treatment. Ezetimibe is commonly added when a statin alone does not reach the goal, and PCSK9 inhibitors are an option for people at the highest risk. A repeat test after starting or changing treatment shows how well it is working.

A cholesterol result means little on its own. It becomes meaningful when read alongside a person’s overall risk.

Conclusion

A cholesterol test is one of the most useful blood tests in heart health, but the numbers only make sense in context. LDL cholesterol matters most, the unit on the report changes how every figure looks, and the right goal depends on each person’s overall risk rather than a single normal range.

For anyone unsure what their own results mean, the report is worth discussing with their doctor or cardiologist, ideally alongside their other risk factors. That conversation turns a column of numbers into a plan.

Recovering After a Coronary Angiogram: What to Expect

September 3, 2026

Most people are home within hours of a coronary angiogram, but knowing what to expect from the TR band, the results conversation, and the days after makes a real difference.

T Wave Inversion on Your ECG: What It Actually Means

August 27, 2026

Key Points

An ECG records the heart from twelve different viewpoints. After each beat the heart resets, and that recovery shows on the tracing as a rounded wave called the T wave.
In most viewpoints that wave points upwards. When it points downwards instead, the report describes it as T wave inversion.
In several viewpoints a downward T wave is entirely normal and expected, so the phrase on its own says very little.
What determines whether it matters is which viewpoints are involved, whether it is new compared with a previous tracing, and whether there are any symptoms.
A previous ECG, if one exists, is often the single most useful piece of information, because a longstanding pattern and a new one carry very different weight.

Of all the phrases that turn up on an ECG report, T wave inversion is among the most common and the least self-explanatory. It sounds like something has been reversed, or has gone wrong in a way that ought to be obvious.

What it describes is narrower than that. A small wave on the tracing points downwards instead of upwards. In several of the heart’s twelve viewpoints that is completely normal. In others it can be important. The phrase alone does not tell you which situation you are in.

What the T Wave Is

Each heartbeat has two halves. The heart muscle activates and contracts, then it has to reset electrically before it can do it again.

On an ECG tracing, the tall spike is the contraction. The rounded wave that follows it is the reset. That second wave is the T wave.

Two ECG tracings compared. In the first the T wave after each beat points upwards, which is the usual pattern in most leads. In the second the T wave points downwards, which is what a report means by T wave inversion — The difference is simply which way the recovery wave points. Whether that matters depends on which of the heart’s twelve viewpoints it appears in, Heart Matters

Because the twelve viewpoints look at the heart from different angles, the same electrical recovery appears differently in each. In most of them the T wave points upwards. In a few it normally points down, and always has.

Where a Downward T Wave Is Simply Normal

This is the part that resolves most people’s concern, and it is worth stating plainly.

One viewpoint, the one labelled aVR, has a downward T wave in essentially everybody. It looks at the heart from the opposite direction to the others, so an upward wave there would be the abnormal finding.

Two others, V1 and lead III, very commonly show a downward T wave in healthy people. So does lead V2 in some. An automated report will still flag these, because software counts rather than interprets.

There is also a pattern sometimes called the persistent juvenile pattern. Children normally have downward T waves across several of the chest viewpoints, and in most people these turn upward through adolescence. In some adults, more often women and more often people of African or Caribbean ancestry, the childhood pattern simply persists. It is a normal variant, not a disease.

In some viewpoints a downward T wave is the expected finding. The software flags it anyway, because it counts rather than interprets.

What Determines Whether It Matters

Three questions decide almost everything, and a cardiologist works through them in this order.

Reassuring
Usually needs nothing beyond an explanation

The inversion sits only in aVR, V1, or lead III, where it is normal.
An older tracing shows the same pattern, unchanged over years.
There are no symptoms, and the rest of the ECG is normal.
The person is young, fit, and the pattern fits a recognised normal variant.

Worth explaining
Usually has a cause that is already known

The inversion accompanies a bundle branch block, where changed conduction alters the recovery wave as a matter of course.
It accompanies a thickened heart muscle, where the pattern is sometimes described as strain.
Certain medicines, including digoxin, change the shape of the recovery wave predictably.
Low potassium or magnesium can flatten or invert it, and correcting the level corrects the tracing.

Investigated promptly
The pattern, the symptoms, or the change over time raises concern

The inversion is new compared with a previous tracing.
It appears across several neighbouring viewpoints rather than one.
It is deep and symmetrical rather than shallow, particularly across the front of the heart.
There are symptoms, especially chest discomfort, breathlessness, or fainting.

The Pattern Cardiologists Look For First

There is one specific arrangement worth knowing about, because it is the reason this finding is never dismissed out of hand.

Deep, symmetrical T wave inversion across the viewpoints that look at the front of the heart, appearing in someone who has recently had chest pain that has since settled, can indicate a critical narrowing in the artery supplying that territory. The person often feels fine at the moment the tracing is taken, which is exactly what makes it dangerous.

It is uncommon. Most T wave inversion is nothing like this. But it is the reason a cardiologist will ask carefully about recent chest pain even when someone currently feels well, and why this particular pattern prompts prompt assessment of the coronary arteries rather than watchful waiting.

Other Causes Worth Knowing

Beyond the coronary arteries, several conditions change the recovery wave.

A previous heart attack leaves permanent changes in the viewpoints that looked at the damaged area, often alongside Q waves.

Thickened heart muscle, whether from long-standing high blood pressure or from hypertrophic cardiomyopathy, alters recovery across several viewpoints. In the inherited condition the changes can be striking, and they are one of the findings that prompts further imaging in a young person.

Inflammation of the heart muscle or its surrounding sac produces widespread changes rather than ones confined to a single artery’s territory.

A clot in the lungs can invert the T waves across the right-sided viewpoints, usually alongside breathlessness and a fast heart rate.

Conditions affecting the brain, including bleeding around it, can produce dramatic deep T wave inversion. These are sometimes called cerebral T waves, and the heart itself is normal.

Athletic training changes the ECG in ways that overlap with disease, and distinguishing the two is a recognised specialty in its own right. Ancestry matters here: T wave inversion across the front chest viewpoints is a well-described normal finding in athletes of African or Caribbean ancestry, and considerably more concerning in others.

What Usually Happens Next

The single most useful step is finding an old ECG. A pattern that has been present for a decade means something entirely different from one that appeared last month, and comparison answers the question faster than any new test.

If there is no previous tracing, or the pattern is new, the usual next steps depend on the picture. A troponin blood test checks whether heart muscle has been damaged. An echocardiogram looks at the muscle thickness and how well each area is moving, which can show a problem in the same territory the ECG pointed at.

Where the coronary arteries are the concern, a stress test or a CT coronary angiogram follows. Where the finding is unexplained in a young person, cardiac MRI is often used, because it shows the muscle in more detail than ultrasound can.

And in a great many cases none of this is needed, because the inversion sits in a viewpoint where it belongs and the conversation ends there.

Conclusion

T wave inversion describes the direction of a small wave on a tracing. That is genuinely all the phrase means, and in several viewpoints the downward direction is the normal one.

What turns it into something worth investigating is context: which viewpoints, whether it is new, and whether anything else is going on. Those are questions a person cannot answer from the report alone, and they are the right things to ask.

If you have been given this finding, two pieces of information will shape the conversation more than anything else. Whether an older ECG exists for comparison, and whether you have had any symptoms, particularly chest discomfort, in the weeks beforehand. Both are worth mentioning without being asked.

Left Ventricular Hypertrophy (LVH) on Your ECG

August 3, 2026

LVH on Your ECG: What Left Ventricular Hypertrophy Means

Key Points

“Left ventricular hypertrophy” on an ECG report means the tracing showed larger than usual electrical voltages, which can happen when the heart’s main pumping chamber has thickened. It is a suggestion, not a diagnosis.
The ECG measures electrical voltage rather than muscle thickness. It picks up a great deal well, but wall thickness is inferred rather than measured, so a normal ECG does not rule thickening out.
Body build affects the reading. Where there is less tissue between the heart and the electrodes, the voltages run higher with no thickening at all.
An echocardiogram settles the question, because it measures the muscle directly rather than inferring it from voltage.
Where genuine thickening is confirmed, the cause matters more than the finding. High blood pressure is by far the most common, and the thickening can partly reverse when the pressure is treated.

Among the phrases that automated ECG software generates, “left ventricular hypertrophy” is one of the more alarming to read. It sounds like a diagnosis of something structural and permanent. Hypertrophy means enlargement. Left ventricular means the main pumping chamber. Put together, it reads as though a machine has just told you your heart is abnormally big.

What the machine has actually done is add up some voltages and compare the total against a threshold. Whether that reflects anything real about your heart is a separate question, and one the ECG is not well equipped to answer.

What the Left Ventricle Does and Why It Thickens

The left ventricle is the chamber that pushes blood out to the entire body. It is the thickest-walled part of the heart because it does the most work.

Like any muscle, it responds to sustained extra load by getting thicker. If it has to push against higher pressure with every single beat, year after year, the wall builds up in response. That is left ventricular hypertrophy.

It is not a disease in itself. It is an adaptation, and the important question is always what it is adapting to.

What the ECG Can and Cannot Tell You

The ECG is a genuinely valuable test, and it is ordered as often as it is for good reason. It detects rhythm disturbances, conduction problems, and the changes of a heart attack quickly, cheaply and reliably. For those questions it is hard to better.

Wall thickness is simply not one of the things it measures directly. It measures electrical voltage at the skin. The reasoning behind the criteria is that a thicker muscle generates a larger electrical signal, so an unusually large signal might indicate a thicker wall.

That reasoning is sound, but voltage is an indirect measure. Depending on which criteria are used and which population is studied, the ECG identifies somewhere between roughly a fifth and a half of people who genuinely have a thickened left ventricle on imaging. It is a screening signal rather than a measurement.

The reason is that voltage at the skin depends on a great deal besides the heart. Chest wall thickness, body size, lung volume, the position of the heart in the chest, and even the exact placement of the electrodes all influence the reading.

A thicker muscle and a thinner chest wall both raise the voltage, which is why the ECG raises the question rather than answering it.

This is why the finding turns up so often in people whose hearts are entirely normal. Where there is less tissue between the heart and the electrodes, the signal arrives stronger and the voltages read higher. Regular endurance training adds to this, partly for the same reason and partly because it produces some genuine and entirely healthy adaptation of the muscle.

The reverse happens too. Someone carrying extra weight, or with lung disease, may have a genuinely thickened ventricle and a completely unremarkable ECG, because the signal is dampened before it reaches the skin. This is why a normal tracing does not settle the question either.

Two ECG tracings compared. In the first the spikes are of usual height. In the second they are markedly taller, which is what an automated report means by voltage criteria for left ventricular hypertrophy — A thicker muscle can produce a larger signal, so the spikes look taller. A thin chest wall can do the same, which is why the finding prompts a closer look rather than settling the question, Heart Matters

What the Report Might Say

The wording varies between machines, and the differences carry meaning.

“Voltage criteria for LVH” is the mildest version. It means only that the numbers exceeded a threshold. In someone with no symptoms and nothing else on the tracing, this on its own very often means nothing.

“LVH with repolarisation abnormality”, sometimes written as a strain pattern, is a more meaningful finding. Here the tracing shows not just large voltages but changes in how the heart muscle recovers between beats. That combination is more likely to reflect genuine thickening and is more strongly linked to cardiovascular risk over time.

“Left atrial enlargement” appearing alongside it adds weight too, because the upper chamber often enlarges in response to a stiff, thickened ventricle below it.

What Causes Genuine Thickening

High blood pressure is by far the most common cause and the reason the finding matters. Every beat against elevated pressure asks more of the muscle, and the wall thickens accordingly. This is often the first hint that blood pressure has been higher than realised for longer than realised.

Aortic stenosis, where the valve at the exit of the left ventricle narrows, creates the same problem more acutely. The chamber has to force blood through a restricted opening, and thickens in response. Aortic stenosis is usually audible as a murmur, so it rarely comes as a surprise on an ECG alone.

Athletic training produces genuine adaptation in endurance and strength athletes, and it is generally benign and reversible with detraining. Distinguishing it from the conditions below is one of the more nuanced judgements in cardiology.

Hypertrophic cardiomyopathy is an inherited condition in which the muscle thickens without any load driving it. It is much less common than the causes above, but it matters because it can affect young people and runs in families. HCM is one reason an unexplained finding in a young person is worth following up rather than dismissing.

Infiltrative conditions such as cardiac amyloidosis can thicken the wall with deposited protein rather than muscle. A distinctive combination sometimes appears here: a wall that looks thick on imaging alongside unexpectedly small voltages on the ECG.

What Happens Next

The finding is usually followed by an echocardiogram, an ultrasound that measures the wall thickness directly and calculates the muscle mass. It answers in twenty minutes what the ECG could only infer, and it also shows whether the chamber is pumping and filling normally.

Watch: what an echocardiogram involves, what it measures, and why it answers questions the ECG can only raise, Heart Matters Educational Series

Blood pressure assessment usually follows too, and often means readings taken at home or over 24 hours rather than a single clinic measurement, since a one-off reading is a poor guide to the pressure the heart has actually been working against.

Where thickening is confirmed and the cause is not obvious, further tests may follow depending on the pattern seen, which might include cardiac MRI, blood tests, or a family history and genetic assessment if an inherited condition is suspected.

Why It Is Worth Knowing About

Confirmed left ventricular hypertrophy is not something to panic about, but it is not nothing either. It is associated over the long term with a higher likelihood of atrial fibrillation, of heart failure, and of stroke, which is why cardiologists take it seriously as a marker even when the person feels entirely well.

The encouraging part is that it is not necessarily permanent. Where high blood pressure is the cause, sustained treatment can produce measurable regression of the thickening over months to years. The muscle that built up in response to pressure can partly unbuild when the pressure comes down. Studies have found that people whose ECG signs of hypertrophy regress with treatment go on to have fewer cardiovascular events than those whose do not.

That makes this one of the more actionable findings on an ECG report. It points at something that can be changed.

Conclusion

“Left ventricular hypertrophy” on an automated ECG report is a prompt to look further, not a verdict. In someone with no symptoms and an otherwise normal tracing it very often reflects nothing more than how the signal reaches the skin. In someone with high blood pressure it may be the first visible sign of what that pressure has been doing quietly for years.

Either way, the next step is the test that measures the muscle directly. An echocardiogram does that, and it is straightforward. What matters most is the conversation about what might be driving it, because for the most common cause, treatment does not just stop the thickening progressing. It can reverse some of it.

The Stress Echocardiogram: What to Expect

June 29, 2026

A stress echocardiogram combines an ultrasound of the heart with an exercise challenge, revealing how the heart performs under pressure, not just at rest.

ApoB Explained: What It Measures and Why LDL Still Matters

June 24, 2026

Key Points

ApoB is a single protein that sits on the surface of every cholesterol particle capable of causing plaque, so an apoB result is effectively a headcount of all the particles that can harm your arteries.
A standard LDL cholesterol result measures the cholesterol carried inside your particles, not how many particles there are. Most of the time the two agree, but in some people they do not.
When LDL cholesterol looks reassuring but apoB is high, this mismatch (called discordance) can reveal hidden risk that a routine cholesterol panel misses.
Strong evidence supports apoB as an accurate marker of cardiovascular risk, particularly in people with high triglycerides, type 2 diabetes, or metabolic syndrome.
ApoB does not replace your LDL, triglycerides, or lipoprotein(a) results. Each tells you something the others cannot, and the best assessment uses them together.
No single number captures your risk. Heart disease is multifactorial, so blood pressure, diabetes, smoking, weight, and family history all matter alongside your lipids. Investigations such as a calcium score add another layer, and whether to add apoB is a conversation worth having with your cardiologist.

There is a lively and sometimes heated debate online about cholesterol. One vocal group argues that the LDL cholesterol number most of us have measured for decades is almost beside the point, and that a different number, apolipoprotein B, or apoB, is the one that truly predicts heart disease. If you have come across this argument and felt unsure who to believe, you are not alone.

The truth, as is so often the case in medicine, sits between the two extremes. ApoB is a genuinely valuable measurement, and the science behind it is sound. It is also not a magic number that makes everything else obsolete. This article explains what apoB actually is, why it can outperform a standard cholesterol result, and how to think about whether it belongs in your own blood tests.

What Is ApoB, Exactly?

To understand apoB, it helps to picture how cholesterol travels through your blood. Cholesterol is a fatty substance, and fat does not dissolve in water. So your body packages cholesterol inside tiny spherical particles that can move through the bloodstream. The particles that drive atherosclerosis, the gradual furring of the arteries, include LDL (low density lipoprotein) and a few close relatives.

Here is the key fact. Every one of these harmful particles carries exactly one molecule of a protein called apolipoprotein B on its surface. One particle, one apoB. This includes LDL, VLDL, IDL, and even lipoprotein(a). So when a laboratory measures your apoB level, it is effectively counting the total number of particles in your blood that are capable of lodging in your artery wall and forming plaque.

Why Counting Particles Can Beat Measuring Cholesterol

A standard lipid panel reports your LDL cholesterol, which sounds like it should tell you everything. But LDL cholesterol measures the amount of cholesterol carried inside your LDL particles. It does not measure how many particles you have.

This distinction matters because particles vary in size. Some people carry a smaller number of large, cholesterol-rich particles. Others carry a large number of small, cholesterol-poor particles. Two people can have an identical LDL cholesterol result while one has far more circulating particles than the other. Since it is the particles themselves that burrow into the artery wall, the person with more particles carries more risk, even though their cholesterol number looks the same.

A useful way to picture it: imagine traffic on a motorway. LDL cholesterol tells you the total weight of cargo being carried. ApoB tells you how many vehicles are on the road. If your arteries are the road, it is the number of vehicles, not the total cargo, that determines how often something collides with the wall.

One protein per particle

Every harmful cholesterol particle carries a single apoB protein, so your apoB level counts every particle that can cause plaque.

Cargo versus headcount

LDL cholesterol measures the cargo carried inside particles. ApoB counts the particles themselves, which is what damages the artery wall.

Why the gap matters

When particle count is high but cholesterol per particle is low, your LDL result can look fine while your true risk is not.

The family of particles apoB counts

ApoB does not just count LDL. It tags several related particles, each of which can contribute to plaque. This is part of why a single apoB result can be so informative: it captures the whole atherogenic family in one number.

LDL

Low density lipoprotein. The most familiar and most numerous of the harmful particles, and the main driver of plaque in most people.

VLDL and IDL

Larger, triglyceride-rich particles and their remnants. They become more important when triglycerides are high.

Lipoprotein(a)

An LDL-like particle with an extra protein attached. Largely inherited, and counted within apoB but not separately identified by it.

Each of these carries one apoB protein, so they are all captured in your total. What apoB cannot do is tell you the breakdown. It will not reveal, for instance, whether a high count is driven by ordinary LDL or by an inherited excess of Lp(a). That is one reason the individual tests retain their value, a point we return to below.

When LDL Cholesterol and ApoB Disagree

Most of the time, your LDL cholesterol and your apoB tell the same story. When both are high, or both are low, doctors call this concordance, and a standard cholesterol panel serves you perfectly well.

The interesting and clinically important situations are the mismatches, known as discordance. This is when your LDL cholesterol looks acceptable but your apoB is high, signalling many small particles quietly carrying on their work. In this scenario, a reassuring cholesterol result can give false comfort. A large 2024 review of 15 studies involving nearly 600,000 people found that apoB was a more accurate marker of risk than LDL cholesterol in every discordance study examined.

Who is most likely to be discordant

You are more likely to have a meaningful gap between your LDL cholesterol and your apoB if you have any of the following: high triglycerides, type 2 diabetes, metabolic syndrome, central weight gain around the abdomen, or a pattern of small dense LDL particles. People in these groups can have a deceptively normal LDL cholesterol while their particle count, and their risk, runs higher. This is precisely the group in which apoB adds the most.

What the Evidence Actually Shows

The case for apoB is strong, and it is worth being clear about what the research does and does not say.

On the supportive side, apoB has performed consistently well as a predictor of heart attack and stroke, often edging out both LDL cholesterol and non-HDL cholesterol, particularly in people whose results are discordant. Because it counts particles directly, it is less affected by the variations in particle size that can distort a standard cholesterol reading. For people with diabetes or high triglycerides, this advantage is most pronounced.

On the cautious side, this does not mean LDL cholesterol is worthless. Far from it. Lowering LDL cholesterol remains the single most trial-tested intervention in all of preventive cardiology. Decades of randomised trials, including the trials that established statins and newer agents such as PCSK9 inhibitors, were built on LDL cholesterol as the target, and the benefit of lowering it is beyond dispute. The online voices declaring LDL cholesterol irrelevant overstate the case considerably.

Why LDL, Triglycerides, and Lp(a) Still Matter

The enthusiasm for apoB has, in some corners of the internet, tipped into dismissing the numbers we have relied on for years. That is a mistake. Each of the established measurements tells you something apoB alone does not, and a good lipid assessment uses them together.

LDL cholesterol

LDL cholesterol is not a flawed or outdated number. It is the most thoroughly validated treatment target in cardiology, and every major guideline still places it at the centre of care. The reason is simple: when we lower LDL cholesterol in clinical trials, heart attacks and strokes fall in proportion, reliably and repeatedly. ApoB refines how we interpret LDL cholesterol in certain people. It does not unseat it. If you are tracking one number over time to see whether your treatment is working, LDL cholesterol remains an entirely sensible choice.

Triglycerides

Triglycerides are a separate and valuable piece of the puzzle. A raised triglyceride level is one of the clearest signals that your LDL cholesterol and apoB may be discordant, because high triglycerides tend to accompany the small, dense, numerous particles that apoB picks up. Triglycerides also respond strongly to lifestyle, which makes them a useful and motivating number to watch. Diet matters here, and the evidence supporting the Mediterranean diet and omega-3 fats is particularly relevant for people with elevated triglycerides.

Lipoprotein(a)

Lipoprotein(a), or Lp(a), deserves its own place on the test request entirely. It is largely inherited, it changes very little over a lifetime, and a single measurement tells you whether you carry this extra, independent layer of risk. While apoB does count Lp(a) particles among its total, it cannot tell you how much of your risk comes specifically from Lp(a), which is why a dedicated Lp(a) test remains worthwhile in its own right. For many people this is a once-in-a-lifetime measurement that meaningfully changes how aggressively their other risk factors should be managed.

What Does a Statin Do to Your ApoB?

This is a question worth answering directly, because it is one of the most useful things to understand about apoB in practice. Statins lower apoB substantially, typically by somewhere in the range of a quarter to nearly half, broadly in step with how much they lower LDL cholesterol. Adding ezetimibe or a PCSK9 inhibitor brings it down further still. So if you are already on treatment, your apoB is very likely already falling alongside your other numbers.

There is one important exception, and it is the reason apoB does not make the individual tests redundant. Statins do very little to lipoprotein(a). Someone can take a statin, watch their LDL cholesterol and apoB fall nicely, and still carry a high inherited Lp(a) that the treatment has barely touched. This is exactly why measuring Lp(a) at least once, separately, remains worthwhile even for people whose apoB looks well controlled.

ApoB Is One Piece of a Multifactorial Picture

Perhaps the most important point in this whole discussion is the one the online debate tends to forget. Cardiovascular disease is multifactorial. No single number, however good, captures your risk on its own, and apoB is no exception.

Your overall risk is shaped by a web of factors that interact with one another. These include your blood pressure, whether you have type 2 diabetes or features of metabolic syndrome, whether you smoke, your weight and waist measurement, your family history, your level of inflammation, and your age. A person with a perfect apoB but uncontrolled blood pressure and a smoking habit is not low risk. Conversely, a moderately raised apoB carries very different weight in an otherwise healthy 45-year-old than in someone with diabetes and a strong family history.

This is why fixating on any one marker, apoB included, can be misleading. The most useful approach is the one your cardiologist actually uses: weighing your lipids alongside every other modifiable factor. Two of the most powerful of those, smoking and high blood pressure, are entirely separate from your cholesterol particles and yet enormously important. You can read a fuller account in our overview of cardiovascular risk factors.

The Role of Investigations

Blood markers tell you about risk. Imaging can tell you what is actually happening in your arteries, and the two together are far more informative than either alone.

The coronary calcium score is the investigation patients most often ask about, and it can be confusing, so it is worth being clear. A calcium score does not measure your cholesterol or your particle count. It measures calcified plaque that has already formed in your coronary arteries, giving a direct picture of the disease itself rather than the risk factors driving it. A high score can prompt more intensive treatment even when your blood results look reasonable. Our article on what a high calcium score really means explains how to interpret the number.

One genuine source of confusion deserves a mention. Because statins can convert soft plaque into denser, calcified plaque, people on a statin can sometimes see their calcium score rise even as their risk falls. This apparent paradox is explained in our piece on statins and your calcium score. For people who need a more detailed look at the arteries themselves, a CT coronary angiogram can show both calcified and soft plaque. Inflammation markers such as hs-CRP can add yet another dimension. Which of these, if any, is right for you depends entirely on your circumstances and is a decision for you and your cardiologist.

Where the Guidelines Stand

The official guidance reflects this balanced reality. Different expert bodies place apoB at slightly different points on the spectrum, but none has discarded LDL cholesterol.

Guideline body	Position on apoB
European (ESC/EAS)	Accepts apoB as an alternative to LDL cholesterol for risk assessment. The 2025 update still confirms LDL cholesterol as the primary target.
Canadian (CCS)	The most apoB-forward. Allows apoB to be used as the primary therapeutic target, especially when triglycerides are raised.
United States (ACC/AHA)	Lists a high apoB as a risk-enhancing factor that supports more intensive treatment, but does not yet set a routine apoB target.
National Lipid Association	Proposes graded apoB targets that become stricter as cardiovascular risk rises.

The main reason apoB has not yet replaced LDL cholesterol everywhere is not weak evidence. It is the absence of a single agreed target across all guidelines, combined with a degree of caution about changing long-established practice. Availability and cost also vary from one health system to another.

Should You Add ApoB to Your Next Blood Test?

In Australia, apoB can be measured by most pathology laboratories, usually reported in grams per litre. It is not always part of a standard lipid panel and may not be routinely rebated, so it is worth asking whether it applies to your situation and whether there is an out of pocket cost.

There is a strong argument for measuring apoB at least once if you fall into a higher-risk group, particularly if you have raised triglycerides, type 2 diabetes, metabolic syndrome, or a family history of early heart disease. It is also useful when your LDL cholesterol seems well controlled but you or your cardiologist remain concerned about residual risk. For someone already tracking LDL, HDL, and lipoprotein(a), as many thoughtful patients now do, apoB is a natural and informative addition rather than a replacement for any of them.

What apoB cannot do is stand alone. It works best alongside your other blood results, any imaging you have had, and the broader picture of your risk factors. The number is only as useful as the conversation it prompts with the person managing your care.

Heart Matters Resource

When in Doubt, Get Checked Out

If you are unsure whether your cholesterol results tell the full story, a focused review of your numbers with your GP or cardiologist is one of the most worthwhile conversations you can have.

Read: When in Doubt, Get Checked Out →

Conclusion

ApoB is one of the most useful advances in everyday cardiovascular risk assessment, because it counts the particles that actually cause plaque rather than estimating the cholesterol they carry. For people whose standard cholesterol result may be quietly misleading, it can uncover risk that would otherwise go unnoticed.

The balanced takeaway is this. LDL cholesterol, triglycerides, and lipoprotein(a) each remain valuable, and apoB sharpens the picture rather than replacing any of them. None of these numbers stands alone, because heart disease is multifactorial: your blood pressure, diabetes, smoking status, weight, and family history all matter alongside your lipids. The most useful conversation you can have is not about a single number, but about the whole picture, with the cardiologist who knows your circumstances.

What Is a Troponin Test, and Why Is It Used for Chest Pain?

June 19, 2026

Troponin is the blood test at the heart of chest pain assessment. If you have been to emergency with chest pain, here is what it measures and what the result means.

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

June 15, 2026

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

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

Right bundle branch block

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.

Tests & Procedures

To Fast or Not to Fast Before a Blood Test?

Understanding Your Cholesterol Test: What Each Number Means

Recovering After a Coronary Angiogram: What to Expect

T Wave Inversion on Your ECG: What It Actually Means

Left Ventricular Hypertrophy (LVH) on Your ECG

The Stress Echocardiogram: What to Expect

ApoB Explained: What It Measures and Why LDL Still Matters

What Is a Troponin Test, and Why Is It Used for Chest Pain?

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

The Echocardiogram: What It Shows and Why It Matters

CT Coronary Angiogram (CTCA): What It Is, What to Expect, and What It Shows

What Is a BNP Test? Understanding This Key Heart Failure Blood Test

The hs-CRP Test: Inflammation, Heart Risk, and Why Context Matters

Leadless Pacemakers: A New Era in Cardiac Pacing

Lipoprotein(a): The Inherited Heart Risk Most People Have Never Heard Of

Drug-Coated Balloons: A New Frontier in Treating Coronary Artery Disease

First-Degree AV Block on Your ECG: What Does It Really Mean?

Why Food Affects Some Blood Tests

Which Heart-Related Tests Need Fasting?

Glucose Tests and Fasting

Fasting glucose

Glucose tolerance test

HbA1c

Glucose results in both units

Cholesterol Tests: When Fasting Helps

Why triglycerides are different

What Counts as Fasting?

Medicines and Fasting

Conclusion

Related Reading

Why Cholesterol Matters

What a Cholesterol Test Measures

LDL cholesterol

HDL cholesterol

Triglycerides

Non-HDL cholesterol

Two Units, One Result

Lipoprotein(a) is the exception

Why There Is No Single “Normal” Number

Preparing for the Test

What Happens After the Result

Conclusion

Related Reading

What the T Wave Is

Where a Downward T Wave Is Simply Normal

What Determines Whether It Matters

The Pattern Cardiologists Look For First

Other Causes Worth Knowing

What Usually Happens Next

Conclusion

Related Reading

What the Left Ventricle Does and Why It Thickens

What the ECG Can and Cannot Tell You

What the Report Might Say

What Causes Genuine Thickening

What Happens Next

Why It Is Worth Knowing About

Conclusion

Related Reading

What Is ApoB, Exactly?

Why Counting Particles Can Beat Measuring Cholesterol

The family of particles apoB counts

When LDL Cholesterol and ApoB Disagree

Who is most likely to be discordant

What the Evidence Actually Shows

Why LDL, Triglycerides, and Lp(a) Still Matter

LDL cholesterol

Triglycerides

Lipoprotein(a)

What Does a Statin Do to Your ApoB?

ApoB Is One Piece of a Multifactorial Picture

The Role of Investigations

Where the Guidelines Stand

Should You Add ApoB to Your Next Blood Test?

When in Doubt, Get Checked Out

Conclusion

Related Reading

What the Bundle Branches Actually Do

What RBBB Looks Like on an ECG, in Plain Language