An updated universal definition of heart failure makes cutoffs for left ventricular ejection fraction (LVEF) more flexible in defining heart failure categories and adds the causes of heart failure, according to a consensus document from four US and international cardiology societies.

The changes are designed to improve prevention and early intervention, said Mary Norine Walsh, MD, chair in the writing committee for the consensus document.

Before the first universal definition, released in 2021, staging of heart failure was often subjective and ambiguous, affecting research, global surveillance, and prevention.

The original definition succeeded in its aims, said Walsh, but needed to be updated 5 years later as prevalence of heart failure continues to rise.

“The importance of early prevention, diagnosis, and management of heart failure continues to be really crucial in view of this increase in prevalence,” said Walsh, who is medical director of the heart failure program at Ascension St. Vincent Heart Center and the Ascension St. Vincent Cardiovascular Research Institute in Carmel, Indiana.

The updated definition, released on June 29, will be useful for future design of research studies and clinical practice guidelines, said Margot Davis, MD, a cardiologist in advanced heart failure at St. Paul’s Hospital in Vancouver, British Columbia, Canada, who was not involved with drafting the updated definition.

Changes in This Update

“We’ve shifted away from rigid definitions of specific ejection fractions to define a specific type of heart failure,” Walsh said. “The updated definition takes into account differences in LVEF based on sex, age, and some differences with ethnicity.”

The categories are simplified: reduced ejection fraction, preserved ejection fraction, and improved ejection fraction (for patients with previous reduced ejection fraction that has increased or normalized). The ejection fraction to classify heart failure in a given patient may differ, depending on their characteristics.

The change makes a lot of sense, Davis noted. She said the prevailing thresholds “never truly reflected the disease process or pathophysiology.” For example, many of the drugs used to treat heart failure work across a range of ejection fractions.

Stages of heart failure (at risk, pre-heart failure, symptomatic, and advanced) mainly remain the same. The definition focuses on early stages, before symptoms are detected, to emphasize prevention and early intervention. It states that social determinants of health — such as poverty, education levels, deprived neighborhoods, and social disparities — as well as geographic variations, can affect risk for heart failure and outcomes of treatment.

The previous definition included “heart failure in remission” rather than “recovery” because relapse was frequent and full and lasting recovery was rare. Davis said the term remission helped clinicians discuss the need for continued monitoring and treatment with their patients. But the updated definition includes “recovery” alongside “remission.”

“Over time, with guideline-directed medical therapy, we certainly know that prognosis in heart failure has improved,” Walsh said, noting that the benefits are being seen at a population level. But she said patients who have recovered can still be at risk and need long-term follow-up and monitoring. Davis added that true recovery remains rare.

Causes of Heart Failure

The definition also classifies heart failure by cause, listing 16 causes plus idiopathic and “other.”

Advances in diagnostics have driven an increase in known causes, Walsh said.

“Imaging and also other diagnoses such as biomarkers have all added to our better understanding of the specific causes of heart failure,” she said. For example, amyloidosis is now better identified through genetic testing and more refined imaging, and stress-induced or Takotsubo cardiomyopathy was discovered through MRI imaging, she said.

Knowing the precise cause can help clinicians target heart failure with specific therapies and help with future research.

This classification will help standardize data from clinical trials and registries, Walsh said. Davis also feels that an agreed-upon list of causes would help with designing research studies. “It remains to be seen whether this particular classification system, which is similar to many others that are out there, will be taken as the absolute.”

Until recently, research studies often included all patients with heart failure and a similar ejection fraction, rather than grouping patients by their particular cause of heart failure, Walsh said.

“More detailed elucidation of the causes can help focus research on phenotypes of heart failure that are actually very different from each other,” Walsh said.

Davis agreed. “As we have advanced our understanding of these specific causes, many of them do have some specific therapy,” and new therapies being developed, such as gene therapies, may target certain causes. “This is the future.”

Walsh and Davis reported having no disclosures.