In short
An ejection fraction of 55% is normal — the usual thresholds are 52% or above for men and 54% or above for women. But a normal percentage does not rule out heart failure, and breathlessness with a normal ejection fraction still needs explaining.
Emergency if: Severe difficulty breathing or breathlessness at rest that will not settle, coughing up frothy pink phlegm while struggling to breathe, blue-tinged lips or skin, chest pain, or fainting and loss of consciousness — call emergency services immediately.
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01
What is ejection fraction, and why is it a percentage?
Left ventricular ejection fraction is the fraction of blood pushed out of the left ventricle during each contraction, measured against the volume of blood in that chamber at the end of filling. Written out, it is the end-diastolic volume minus the end-systolic volume, divided by the end-diastolic volume, multiplied by 100. That formula explains the single most common misreading of an echo report: a healthy left ventricle does not empty itself, so a number near 100% is not the target and would not be normal.
The number is usually produced by two-dimensional echocardiography, which remains the most widely used method because it is accessible and inexpensive. The recommended way to calculate it is the biplane method of disks, also called the modified Simpson's rule. Quantitative measurement is preferred to visual estimation, because eyeballing the ventricle is highly subjective and operator-dependent, and quantitative methods reduce differences between observers.
This is why a five-point difference between two scans is often measurement rather than change. Accuracy also falls when there are regional wall motion abnormalities or when the ventricle is dilated or irregularly shaped, because the method assumes a predictable geometry. If a number matters for a decision, it is normal practice to repeat or confirm it rather than act on a single reading.
02
Is 55% normal, borderline, or the start of heart failure?
It is normal. By American Society of Echocardiography criteria, a normal ejection fraction on two-dimensional echocardiography is 52% or more for men and 54% or more for women. A reading of 55% therefore sits inside the normal range for either, and it is not a borderline value, a warning shot, or the first stage of anything. Reports that print a normal range alongside the result often make this obvious, and many do not.
What a normal ejection fraction does not do is settle the question of heart failure. Heart failure with preserved ejection fraction is defined by an ejection fraction of 50% or more in someone who has heart failure — so the diagnosis lives alongside a normal percentage rather than being excluded by it. Breathlessness with a normal ejection fraction is a reason for more thinking, not less, and usually for looking at the filling side of the report.
The percentage becomes a treatment threshold at the lower end. Ejection fraction assessment should be performed for everyone after a myocardial infarction to help with risk stratification and guide management, and an ejection fraction of 35% or less in someone with heart failure or a previous myocardial infarction indicates eligibility for an implantable defibrillator to prevent sudden cardiac death. Those are the numbers that change what is offered.
03
HFrEF, HFmrEF and HFpEF: what the categories mean
These labels split heart failure by the ejection fraction alone. Heart failure with reduced ejection fraction, HFrEF, means an ejection fraction of 40% or less. Heart failure with mildly reduced ejection fraction, HFmrEF, covers 41% to 49%. Heart failure with preserved ejection fraction, HFpEF, means 50% or more. A fourth label, HFimpEF, describes heart failure with improved ejection fraction: a ventricle that was previously 40% or less and now measures above 40%, with the consensus definition also asking for a rise of at least 10 points confirmed on a later reading.
Because the categories are defined by one number, they describe the pump measurement and not how unwell a person feels. Two people with the same ejection fraction can be walking different distances before stopping. The categories earn their place because the number changes what is offered — the defibrillator threshold at 35% or less is the clearest example — and because they let research describe groups consistently.
So the useful question is not which label appears on your report but which decisions the number unlocks and which it does not. If your ejection fraction is in the preserved range and you are breathless, the next part of the report — the filling and pressure measurements, the left atrial size, the valves — usually carries more information than the headline percentage. It is also worth writing down which category you were placed in and at what percentage, because the previous number is what gives the next scan its meaning.
04
Trivial MR and mild TR: do leaky valves need treating?
Usually nothing at all needs doing, because small leaks are the norm in normal hearts. In a Doppler study of 32 healthy volunteers aged 21 to 49, regurgitation was detected at the pulmonary valve in 100%, at the tricuspid valve in 100%, at the mitral valve in 56% and at the aortic valve in 6%. The jet area and jet length were generally small, and the authors concluded that trivial regurgitation from the pulmonary, tricuspid and mitral valves is common in healthy people.
The words on your report map onto measurements. Trace or trivial mitral regurgitation means a small central jet occupying less than 20% of the left atrium, with a vena contracta — the narrowest part of the jet — under 3 mm. The next band up, which the staging tables call progressive mitral regurgitation and grade 1+ to 2+, is a central jet of about 20% to 40% with a vena contracta that does not exceed 7 mm and an effective regurgitant orifice area below 0.4 square centimetres; that band spans what reports describe as mild and as moderate. Severe is a different order of finding: an effective regurgitant orifice area of 0.4 square centimetres or more, a vena contracta of 7 mm or more, or a central jet above 40%.
The follow-up interval tells you how seriously the leak itself is taken. For mild mitral regurgitation, the recommended interval for repeating the echocardiogram is 3 to 5 years. That is a watching schedule rather than a treatment plan, and it is a reasonable thing to ask your doctor to write on the report so that you are not re-scanned anxiously every year without a reason. That interval assumes you stay well between scans. New breathlessness, breathlessness lying flat, or a clear drop in what you can do without stopping is a reason to be seen rather than to wait for the date on the report.
05
Grade 1 diastolic dysfunction: how serious is impaired relaxation?
Grade 1, also written as impaired relaxation, describes a ventricle that is slower to relax and refill. Without rapid diastolic suction, the left atrium empties more gradually and its own contraction does more of the work, which is why the early filling wave is small relative to the wave produced by the atrium and the E/A ratio falls below 0.8, the threshold used to define the pattern. Crucially, this is described as a ventricle with impaired relaxation but normal filling pressures.
It is also common. In a community cohort of 1,005 people with a median age of 63, 26% were classified as having grade 1 diastolic function, far more than the small number with grade 2 or 3. Finding it on a report is therefore not unusual, and it is not in itself a diagnosis of heart failure, which requires elevated filling pressures rather than slow relaxation alone.
Common is not the same as harmless, and this is where sources pull in different directions. The same cohort was followed for a median of 19.7 years, and grade 1 diastolic function was associated with all-cause mortality with a hazard ratio of 4.05 (95% CI 3.22 to 5.09). That headline figure is not adjusted for age, and slow relaxation is itself strongly age-related, so it overstates what the finding means on its own. Two other numbers from the same paper matter as much: among those with impaired relaxation and no other clinical or echocardiographic abnormality the hazard ratio was 2.71 (1.89 to 3.88), and cardiovascular mortality remained associated after adjustment for age, sex and other conditions at 2.43 (1.16 to 5.05), while the association with non-cardiovascular death did not survive that adjustment. The authors described it as a potential marker of cardiovascular and cognitive risk, and not necessarily a benign finding that is normal with age. The sensible reading is: not an emergency, and not a reason to ignore blood pressure, glucose or lipids.
06
LVH, LA dilatation and "no RWMA" — what they tell your doctor
Left ventricular hypertrophy on an echo means increased muscle mass, defined as about 90 to 95 grams per square metre or more in women, depending on which reference the laboratory follows, and 115 grams per square metre or more in men. A hypertrophied ventricle tends to relax poorly, and under the right loading conditions that raises pressure in the left atrium. In practice it usually sends the conversation back to blood pressure control rather than to the heart itself.
Left atrial size behaves like a barometer for the pressures the chamber has been exposed to over time. Enlargement of 30 millilitres per square metre or more is usually seen when diastolic dysfunction is significant and filling pressures are raised, though many laboratories report against a threshold of 34, and increasing left atrial size correlates with higher filling pressures and worse outcomes in diastolic heart failure. A normal left atrial size essentially argues against elevated filling pressures, although an enlarged atrium can also occur without them.
"No RWMA" means no regional wall motion abnormality: no segment of the left ventricular wall was seen moving differently from the rest. It is worth noticing for two reasons. It is one of the things an echocardiogram is specifically asked to look for in suspected acute coronary syndrome, alongside left ventricular function and mechanical complications. And its absence also makes the ejection fraction number more trustworthy, since the standard calculation is less accurate when regional wall motion abnormalities are present.
07
Can ejection fraction improve?
Yes, and the classification system has a name for it. Heart failure with improved ejection fraction describes someone whose ejection fraction was 40% or less and now measures above 40%, usually after a rise of at least 10 points. A separate category exists because this happens often enough to need describing, and because the history of a previously low ejection fraction continues to matter even after the number rises.
Two cautions belong with that good news. First, measurement variability is real, so a modest rise on a single scan is not proof of recovery; quantitative measurement reduces differences between observers but does not abolish them. Second, ejection fraction is only one dimension of the report, and a number that has moved into the normal range does not by itself say that symptoms, filling pressures or valve findings have moved with it.
The practical rule is that an improved ejection fraction is a reason to talk to your cardiologist, never a reason to stop or reduce anything on your own. Ejection fraction after a myocardial infarction is used to guide management and device decisions, which means the same number is being used by your doctor for purposes that are not obvious from the report alone.
08
Which echo findings need a cardiologist this week?
Symptoms outrank the report. NHS advice is to seek urgent medical care the same day if you feel breathless when lying down or during everyday activity, if you are coughing up frothy pink phlegm, or if you have suddenly gained weight. Those three are the classic signs that fluid is backing up, and they are worth acting on whatever percentage is printed on your echo.
Among the numbers themselves, a few should not sit in a drawer until the next routine appointment: an ejection fraction of 40% or less, which is the definition of heart failure with reduced ejection fraction; an ejection fraction of 35% or less in someone with heart failure or a previous myocardial infarction, because of the defibrillator threshold; and regurgitation reported as severe, with an effective regurgitant orifice area of 0.4 square centimetres or more.
Much of the rest can wait for an ordinary appointment. Trivial or mild regurgitation, grade 1 diastolic function without symptoms, and an ejection fraction inside the normal range are findings to discuss, not to act on overnight. Ask for two things at that appointment: what interval the echo should be repeated at, and which of your own symptoms should bring you back sooner.
Acting on an echo report
Routine — see a doctor
Trivial or mild valve regurgitation, grade 1 diastolic function, mild left ventricular hypertrophy or an ejection fraction in the normal range, with no symptoms — a routine appointment to agree the repeat-scan interval (3 to 5 years for mild mitral regurgitation) and to work on blood pressure, glucose and lipids.
Same-day — call promptly
New breathlessness during everyday activity, breathlessness when you lie flat or that wakes you at night, or swelling of the feet, ankles, legs or abdomen with a sudden weight gain — ask for an urgent same-day appointment or ring your health line, whatever the ejection fraction says.
Emergency — act now
Severe difficulty breathing or breathlessness at rest that will not settle, coughing up frothy pink phlegm while struggling to breathe, blue-tinged lips or skin, chest pain, or fainting and loss of consciousness — call emergency services immediately.
Values mentioned in this story
Each one opens a visual guide with its normal range and what moves it — upload a report and we place your own numbers on the same scale.
Sources
- StatPearls: Ejection Fractionncbi.nlm.nih.gov
- StatPearls: Mitral Regurgitationncbi.nlm.nih.gov
- Doppler echocardiographic evaluation of valve regurgitation in healthy volunteerspmc.ncbi.nlm.nih.gov
- Left ventricular diastolic function and dysfunction: central role of echocardiographypmc.ncbi.nlm.nih.gov
- Association of impaired relaxation mitral inflow pattern (grade 1 diastolic function) with long-term mortalitypmc.ncbi.nlm.nih.gov
- NHS: Heart failurenhs.uk
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