How Much Can Ejection Fraction Improve?

A low ejection fraction is not a fixed verdict. For many people the number climbs with treatment, and some return to the normal range of 50% or higher. How far it rises depends less on how low it started than on why the heart weakened and how much of the muscle is still alive. Even a big recovery is better described as remission than cure, because the heart can slip back if the underlying support is removed.¹

What Counts as a Real Improvement

Ejection fraction (EF) is the share of blood the main pumping chamber pushes out with each beat. About 50% to 70% is normal. Doctors call it heart failure with improved ejection fraction when a low EF has come back up; your records may list it as HFimpEF.² The usual bar is a starting EF of 40% or less, a rise of at least 10 points, and a later reading above 40%.³ Some doctors count only recovery to above 50% as full recovery.

Going from 25% to 38% is a 13-point gain, but it is still below the 40% line. Going from 35% to 45% meets the bar for improved EF.

Small changes can also be measurement noise. Repeat ultrasound readings of EF in the same person can differ by several points, and an ultrasound EF can sit up to about 15 points away from an MRI reading of the same heart.⁴ A shift of a few points between scans may not be a real change. Ask whether your scans used the same method, and judge trends over several readings, since one good scan matters less than whether later scans confirm it.

EF is also only part of the picture. Symptoms, walking distance and blood tests like BNP show how the heart is doing too. Someone can feel much better before the EF number moves much, and a normal EF does not erase the earlier damage to heart cells.

Causes That Often Recover the Most

A heart that beats too fast for weeks or months, often from atrial fibrillation, can weaken badly. Once the rate or rhythm is controlled, EF improves or normalizes, in one group within 6 months for everyone.⁵ Treatment can mean medicines that slow the rate, a shock to reset the rhythm, or a catheter procedure that targets the faulty electrical spot, depending on the type of rhythm. In people with new heart failure from this cause, EF rose on average from about 30% to 49% within about 3 to 4 months.⁶ When EF starts below 20%, recovery can be slower and take longer than 6 months.⁷ If the fast rhythm returns, the heart can weaken again quickly.⁸

In women with heart failure around childbirth, about half recovered fully.⁹ Recovery often took more than a year, averaging around 19 months.¹⁰ In another group, half of those who recovered did so within 8 months, but some took over 2 years.¹¹

Repairing or replacing a faulty valve can let the pump recover.¹² People with a better EF before surgery were more likely to recover afterward.¹³ After valve replacement, many people had a normal resting EF by about 20 months.¹⁴

These causes recover more than a heart attack scar does because the muscle is overworked or stunned rather than dead. Removing the strain lets living muscle cells resume normal pumping. Dead muscle turns to scar, and scar cannot contract again.

How Much Medicines Can Raise It

Medicines that block stress hormones, such as beta-blockers and drugs acting on the hormone system that controls blood pressure, can make an enlarged heart shrink back toward normal size.¹⁵ A smaller, better-shaped chamber squeezes more efficiently, so EF rises. In one group with mildly reduced EF, the heart reshaped itself more often on beta-blockers, about 24% versus 18%.¹⁶ The benefit was larger in people with a resting heart rate of 75 or higher or with atrial fibrillation.¹⁷

Among people starting sacubitril/valsartan with an EF under 35%, the outlook after a year varied widely.¹⁸ In the group most likely to improve, only about 4% were still under 35% a year later, while in the least likely group about 84% were.¹⁹

The first months follow a pattern. Doses are usually started low and raised every few weeks, as long as blood pressure and kidney tests allow it. Tiredness or lightheadedness early on often eases as the body adjusts, but dizziness or fainting should be reported rather than quietly endured. A repeat scan is commonly done after about 3 months at good doses, because the heart needs time on full treatment before a change can show. The cause of weakness matters more than the drug list, and scarring from past heart attacks limits how high EF can go.

Procedures and Devices That Can Add More

Heart muscle starved of blood can stop pumping while still alive, and it can recover once blood flow is restored by bypass surgery or stents.²⁰ In one group, EF rose from about 39% to 50% after bypass when the muscle was starved but still alive.²¹ Areas with damaged or scarred muscle showed no early recovery.²² Scans, cardiac MRI among them, can show whether muscle that is not pumping is still alive or has already turned to scar. That helps doctors avoid operations that carry risk but are unlikely to improve the pump.

Cardiac resynchronization therapy uses a pacemaker that helps both sides of the heart beat in step when the electrical signal is delayed. About 1 in 6 people given one gained more than 15 points of EF.²³ The strongest responders gained around 17 or 18 points on average.²⁴ Many people gain 5 points or less, so results vary widely.²⁵

An ECG showing a wide, delayed beat, particularly a pattern called left bundle branch block, makes a resynchronization pacemaker more likely to help. People with a narrow beat are less likely to benefit, which is part of why the ECG is checked before the device is offered.

In very advanced failure, a pump implanted to help the heart can rest it enough to recover in some people.²⁶ In one program, half of those given the full protocol had the pump removed within 18 months, with an average EF near 57%.²⁷ Some of them reached exercise ability within the range of healthy people their age.²⁸

That kind of recovery happens in a minority, usually with careful protocols. For most people the pump is a long-term support or a bridge to transplant. Ask a specialist center whether recovery is a goal in your case.

Who Is Most Likely to Recover

The more scarred muscle the heart has, the lower EF tends to be later on.²⁹ On MRI, people with fewer scarred segments, such as 4 or fewer, were more likely to regain pumping after bypass.³⁰

Women recover EF more often than men, about 41% versus 27% in one large group.³¹ A shorter illness and weakness not caused by heart attacks also favor recovery.³² Pooling many studies, women had about 1.5 times the odds of recovery.³³ A longer-standing weakness gives the heart more time to scar and stretch, so reaching full doses soon after diagnosis gives the best chance, and delays in follow-up can cost recovery.

Predictors describe groups, not a certain outcome for any one person. Men and people with scars still often improve somewhat.

Exercise and Cardiac Rehab

Moderate aerobic exercise raised EF about 4 points on average in people with reduced EF.³⁴ Programs lasting 6 months or more raised it about 6 points, versus about 2 for shorter ones.³⁵ Interval training raised EF about as much as steady exercise, while weight training alone did not clearly raise it.³⁶ Ask for a referral to cardiac rehab and plan to stay with it beyond 3 months.

Rehab sessions are supervised, often two or three times a week, with heart monitoring so staff can see how your rhythm and blood pressure respond. Intensity is raised gradually, so you are not pushed beyond what your heart can handle. Rehab also teaches safe activity at home, including which symptoms mean stopping.

Staying Improved After Your EF Rises

People whose EF improved had about a third the death risk of those whose EF stayed low.³⁷ They also needed fewer hospital stays.³⁸

The gain can slip, though. About 46% of people with recovered EF saw it fall again within 5 years.³⁹ In another group, 28% had EF drop below 40% within 3 years.⁴⁰ When medicines were stopped in people with recovered weak hearts, about 44% relapsed within 6 months, versus none who continued.⁴¹ Don’t stop or reduce heart medicines on your own after a good scan.

Follow-up usually includes repeat scans every year or so, to catch a slide before symptoms return. New breathlessness, swelling in the legs or a racing heartbeat should prompt an earlier check rather than waiting for the next visit.

A large rise in EF can change whether a defibrillator is recommended, since the device is usually offered when EF stays low. The decision depends on the cause and on how long EF has stayed up, not on one good scan. Ask your doctor before assuming a planned device is no longer needed, because the choice is made case by case.