Heart Failure Has a New Universal Definition. What Changes in 2026

Four of the world’s leading cardiology organizations have published a new universal definition of heart failure, in a consensus document that changes the way the condition is described and classified. The update places greater emphasis on identifying patients before the symptomatic stage, on the underlying cause of disease, and on its evolution over time, while moving away from rigid ejection fraction thresholds as the central element of classification.

The new framework is highlighted in a report published in JAMA and represents the second universal definition of heart failure, following the first one adopted in 2021.

The consensus document was developed by the American Heart Association (AHA), American College of Cardiology (ACC), European Society of Cardiology (ESC), and World Heart Federation (WHF), in collaboration with the Heart Failure Society of America, the Heart Failure Association of the ESC, and the Japanese Heart Failure Society.

The full document was published simultaneously in several leading international cardiology journals.

Why a new definition was needed

The authors note that heart failure remains a major health problem, with increasing prevalence worldwide, while differences in terminology and classification may complicate clinical practice, research, epidemiological surveillance, and prevention programs.

The first universal definition, published in 2021, sought to standardize the terminology used internationally and gave an important role to the concept of “pre-heart failure” — stage B — in which abnormalities are already present that indicate an increased risk of progression to symptomatic disease.

The new consensus further refines this model and shifts part of the focus from treating established heart failure toward early identification of people at risk and prevention of disease progression.

Ejection fraction: less emphasis on rigid numerical thresholds

One of the most important changes concerns the classification of heart failure according to left ventricular ejection fraction.

Instead of relying primarily on rigid numerical cutoffs, the new definition groups clinical phenotypes into three broader categories: heart failure with reduced ejection fraction, heart failure with preserved ejection fraction, and heart failure with improved ejection fraction.

Experts argue that ejection fraction values should be interpreted in clinical context, because they may vary according to sex, age, ethnicity, and the imaging method used. Fixed thresholds may also fail to capture the full spectrum of disease and may influence patients’ eligibility for clinical trials.

The “pre-heart failure” stage gains greater importance

The new document retains the four-stage model, from A to D, but places particular emphasis on stage B — “pre-HF” or pre-heart failure.

This stage is considered an important window for early detection, monitoring, and individualized intervention before the patient develops the clinical manifestations characteristic of heart failure.

The approach reflects a change in perspective: preventing progression to symptomatic heart failure becomes a central component of the conceptual framework, alongside treatment of already established disease.

A universal classification of the causes of heart failure

Another new element is the introduction of a standardized classification of heart failure etiologies.

The document includes, among others, ischemic, hypertensive, valvular, infiltrative, infectious, inflammatory, toxic, hereditary, metabolic, pregnancy-related, stress-induced, congenital causes, as well as conditions associated with high cardiac output.

The new taxonomy seeks to move beyond the much broader distinction between ischemic and nonischemic heart failure. More precise identification of the underlying cause may have implications both for treatment selection and for patient registries and clinical trial design.

“Improvement,” “remission,” and “recovery” do not mean the same thing

The consensus also emphasizes the dynamic nature of heart failure. A patient’s course is not necessarily linear, and cardiac function may improve substantially with treatment.

The new framework distinguishes between improvement, remission, and recovery. An increase in ejection fraction does not automatically mean that the disease or cardiovascular risk has disappeared.

Even patients whose cardiac parameters return to normal may retain vulnerability and may require individualized long-term monitoring and treatment.

Artificial intelligence also appears in the new definition

The document also discusses emerging tools for the early detection of heart failure. These include electrocardiograms analyzed with artificial intelligence, which could help identify left ventricular dysfunction and estimate the risk of developing heart failure.

Experts caution, however, that such technologies must be validated in diverse populations and in healthcare systems with different levels of resources before they can be widely used in clinical practice.

Heart failure viewed as a disease with different trajectories

The new definition also gives greater attention to geographic differences, access to healthcare, and social determinants of health, all of which may influence both the development of heart failure and patient prognosis.

The distinction between worsening heart failure and decompensation is also clarified. Decompensation is associated with the need for treatment intensification or therapeutic intervention, without necessarily implying hospitalization or sudden clinical deterioration.

Overall, the new consensus proposes that heart failure should be viewed less through isolated numerical values and more as a syndrome with different etiologies and phenotypes that can evolve along variable trajectories.

According to the American College of Cardiology, the 2026 universal definition is also expected to provide one of the foundations for a future international heart failure guideline, anticipated for publication in 2027.