Entresto improves ejection fraction by an average of 5.2 percentage points at 6 months and 9.4 percentage points at 12 months, based on the PROVE-HF study of patients with heart failure and reduced ejection fraction. That means someone starting at an ejection fraction of 25% could realistically see it climb to around 34% after a year on the medication, though individual results vary widely.
What the Numbers Look Like Over Time
Improvements in ejection fraction don’t happen overnight. The PROVE-HF trial, one of the largest studies tracking this specific outcome, measured heart function at regular intervals and found a clear upward trend that continued building through the first year. The 5.2-point gain at six months roughly doubled to 9.4 points by twelve months, which suggests the heart continues remodeling well beyond the first few months of treatment.
This timeline matters for a practical reason: guidelines often recommend reassessing heart function at three months to decide whether a patient needs an implantable defibrillator or other device. But research from the ENVI study found that three out of five patients who initially qualified for a device no longer met the criteria after six months of optimized therapy. The data suggests waiting at least six months before making major treatment decisions based on ejection fraction, since the heart may still be improving.
How Entresto Reverses Heart Damage
Entresto combines two active components that work on different systems simultaneously. One blocks a hormone system that causes blood vessels to constrict and the heart to work harder. The other prevents the breakdown of natural proteins that help blood vessels relax, reduce fluid retention, and lower the strain on the heart. Together, they tackle heart failure from two angles at once.
The ejection fraction improvement isn’t just the heart pumping harder in the moment. Entresto triggers what cardiologists call “reverse remodeling,” meaning the heart physically changes shape and size over time. The left ventricle shrinks back toward its normal dimensions as both its resting and pumping volumes decrease. The left atrium, which often stretches under pressure in heart failure, also gets smaller. These structural changes are what produce the lasting gains in ejection fraction.
At the cellular level, several processes drive this transformation. The drug reduces scar tissue formation in the heart muscle by blocking fibrosis pathways. It improves how heart cells handle calcium, which is essential for proper contraction and relaxation. It also restores the energy-producing capacity of heart cell mitochondria and reduces the oxidative stress and inflammation that accelerate heart failure progression. In patients taking Entresto, blood markers of fibrosis and tissue damage drop significantly, reflecting these changes happening inside the heart.
Does the Dose Matter?
The relationship between Entresto dose and ejection fraction improvement is more nuanced than you might expect. A 2025 meta-analysis comparing high-dose and low-dose Entresto found no statistically significant difference in ejection fraction improvement overall. However, when researchers narrowed the analysis to studies where the high dose was truly at the target level (200 mg twice daily), a small but real difference emerged: the higher dose produced about 1.8 additional percentage points of ejection fraction improvement.
Where dose made a clearer difference was in reducing NT-proBNP, a blood marker that reflects how much stress the heart is under. Higher doses produced a significantly greater drop in this marker. Since lower NT-proBNP levels are linked to better long-term outcomes regardless of ejection fraction, reaching the target dose still matters even if the ejection fraction difference seems modest. If you can’t tolerate the full dose due to low blood pressure or other side effects, the evidence suggests that a lower dose still delivers meaningful heart remodeling.
Tracking Progress With Blood Tests
NT-proBNP levels offer a useful window into how well Entresto is working before your next imaging study. Research has quantified the relationship: for every 1,000-point drop in NT-proBNP, ejection fraction increases by about 6.7 percentage points on average. The same study found that this biomarker drop also corresponded to measurable reductions in heart chamber volumes, confirming that the structural remodeling was real.
This correlation gives both patients and clinicians a way to gauge response between echocardiograms. A substantial early drop in NT-proBNP is a strong signal that the heart is responding to treatment and that ejection fraction gains are likely to follow on the next imaging study.
Who Benefits Most
Entresto is primarily studied and approved for heart failure with reduced ejection fraction, meaning patients who start with an ejection fraction at or below 40%. These are the patients in whom the 5- to 9-point improvements were documented. The lower your starting ejection fraction, the more room there is for improvement, though the degree of response varies from person to person based on the underlying cause of heart failure, how long the condition has been present, and how much irreversible scarring exists in the heart muscle.
Some patients experience far more dramatic improvements than the averages suggest. In the ENVI study, 60% of patients who initially had ejection fractions low enough to warrant a defibrillator improved past that threshold within six months. Others see more modest gains. The averages from clinical trials represent a wide range of individual responses, and there’s currently no reliable way to predict exactly how much any single person’s ejection fraction will improve before starting treatment.