The new heart failure (HF) guidelines from the European Society of Cardiology (ESC) introduce new terminology, offer a new organization of therapies along the continuum of progression, and add greater emphasis to treating disease at its earliest stages.

Among the most notable changes, the mildly reduced phenotype of HF has been eliminated. That leaves just two phenotypes: The preserved function phenotype retains the definition of a left ventricular ejection fraction (LVEF) of 50% or greater, and the reduced phenotype is now defined as LVEF < 50%, replacing the ≤ 40% definition from the last guideline update in 2021.

“The mildly reduced LVEF phenotype was introduced in previous guidelines to focus on patients not usually included in clinical trials. However, we know that these patients share similar pathophysiology — and benefit from similar treatments — as those with reduced LVEF,” said Marianna Adamo, MD, PhD, a cardiology interventionalist, specialist in HF, and an associate professor at the University of Brescia in Brescia, Italy.

Stages of HF

The ESC guidelines add new classification stages for HF:

• Stage A is defined by risks and early signs of HF in the absence of symptoms, structural heart changes, or elevated biomarkers.
• Stage B is described as pre-HF, and it also captures a status before symptoms but requires at least one of three signs of impending symptomatic disease: structural abnormalities, abnormal cardiac function, or elevated biomarkers such as natriuretic peptides or troponin.
• Stage C describes symptomatic HF caused by structural or functional cardiac abnormalities, but it is subdivided into the preserved and reduced LVEF phenotypes.
• Stage D identifies advanced heart disease with significant symptoms, cardiac dysfunction, and recurrent HF events despite therapy.

This new format has relevance to the decision to substitute the term foundational medical therapy for the previously employed guideline-directed medical therapy (GDMT). Both identify treatments considered essential at each stage, but many have been moved forward in disease progression since the last guidelines.

The new classification system aims to focus more on prevention and early diagnosis, according to the ESC. The system was adopted from 2022 guidelines jointly issued by the American Heart Association (AHA), the American College of Cardiology (ACC), and the Heart Failure Society of America (HFSA).

Adamo, along with her co-chair, Lars Køber, MD, DMSc, who is a professor of cardiology at the Copenhagen University Hospital, Copenhagen, Denmark, led the Task Force that developed the new guidelines. Both spoke on key aspects of the guidelines, coinciding with their publication, at the European Society of Cardiology (ESC) Congress 2026. 

Commenting on the decision to move to the FMT from GDMT, Køber suggested that the numerous therapies introduced in recent years have created “some uncertainty as to what GDMT actually means today.” The new term separates the key therapies with a mortality benefit but does not exclude others from being considered guideline-directed.

Details on the Four Stages

For stage A, tight control of systolic blood pressure (< 130 mm Hg) is a class I recommendation. In addition, SGLT-2 inhibitors and the mineralocorticoid receptor antagonist (MRA) finerenone are considered class I therapies in selected patients.

SGLT-2 inhibitors are considered FMT for patients with atherosclerotic cardiovascular disease; MRA is considered for people with diabetes at risk for HF or chronic kidney disease.

Additional drugs are recommended in stage A for cancer survivors, and for patients with arrhythmias, pulmonary disease, congenital heart disease, endocrine disease, and/or prior myocardial infarction.

In stage B, two more drugs, listed as GDMT in prior guidelines, are now considered FMT for patients with HF with reduced injection fraction (HFrEF): beta blockers for patients with LVEF < 50%, and renin-angiotensin inhibitors (ACE inhibitors or angiotensin receptor blockers) for patients with LVEF < 40%. Eplerenone becomes the preferred MRA in patients with LVEF < 40% and a prior MI, HF symptoms, or diabetes.

Stage C and stage D constitute chronic HF, meaning all patients with HFrEF should be on all four pillars described as GDMT in the prior guidelines and henceforth referred to as FMT. In addition to a beta blocker, these drugs include MRA, SGLT2, and an angiotensin receptor neprilysin inhibitor (ARNI) FMT. As before, the ARNI replaces the conventional renin-angiotensin inhibitors in the stage C and D HFrEF populations.

The new guidelines have also created a category of additional medical therapies (AMTs). In appropriate HF subtypes, AMTs are recommended on top of FMT and are recognized as having important benefits in the new guidelines. For example, a cardiac glycoside such as digoxin could be an AMT in patients with HFrEF who remain symptomatic on FMT.

Moreover, the new guidelines separate AMT into medical or interventional categories. While these include both class IIa (‘should be considered’) and class IIb (‘may be considered’) drugs and procedures, some are expected to provide further event reductions on top of FMT even if they are not expected to provide an additional survival benefit.

Other AMTs might not be associated with event reductions but are associated with improvements in quality of life, which the guidelines identify as a major potential benefit for patients living with advanced HF. Examples of these types of AMT supported with class I evidence include exercise training and cardiac resynchronization therapy in advanced heart failure.

Beyond the Four Pillars

“More and more therapies beyond the four pillars are being added to the guidelines, and we know these can play an important role in optimal care,” said Shelly Hall, MD, chairwoman of the ACC’s Heart Failure and Transplant Council.

Referring to the next set of joint guidelines from the AHA/ACC/HFSA, expected sometime in 2027, Hall said, “there are a lot of good ideas in these guidelines that I hope will be adopted.”

She expressed particular enthusiasm for the separation of therapeutic options into medical and interventional categories. This provides needed structure to accommodate new advances as they become available, Hall said.

“It organizes what we have now and what potentially we will have in the future into really good buckets,” said Hall, who is chief of transplant cardiology, mechanical circulatory support, and advanced HF at Baylor University Medical Center in Dallas.

She has no reservations about the decision to eliminate the mildly impaired LVEF phenotype.

“I never liked the division. It was confusing, and we know heart failure is progressive,” Hall said. She believes the mild phenotype was never well understood or adequately supported by evidence, and it left clinicians “in the lurch” when trying to select the best care for a patient.

Hall praised the decision to eliminate the term acute heart failure in favor of the terms compensated and decompensated.

“Patients develop heart failure over time – it is not typically a sudden onset,” Hall said. “They also still have heart failure even if the symptoms are controlled. The terms compensated and decompensated make that clearer.”

Although the characteristics of stage A HF in the new ESC guidelines includes “pretty much anyone with coronary artery disease,” Hall agrees strongly with the idea of identifying at-risk patients early for the goal or preventing or slowing the progression. Basically, she found this emphasis and the new terminology “very exciting” because of what it will offer to clinicians.

Overall, “these new guidelines are very forward thinking,” Hall said. She is not part of the writing committee for the next set of AHA/ACC/HFSA joint guidelines, but she expressed hope that those who are incorporate the main messages.

“It certainly would be nice if we were unified behind many of these ideas,” Hall said.

Adamo reported receiving funding from Abbott, Edwards Lifesciences, and Medtronic. Køber reported having financial relationships with AstraZeneca, Boehringer Ingelheim, Novartis and Novo-Nordisk. Hall reported having financial relationships with Abbot, CareDx. CVRx. And Natera.

Ted Bosworth, a career medical writer based in New York City, has been covering advances in clinical medicine, including cardiology, for several decades.