Because heart failure patients with recovered ejection fraction are a complex and diverse group, little consensus has emerged on how to define, diagnose, and manage this growing population.
To provide some clarity for identifying and treating these patients, a Journal of the American College of Cardiology scientific expert panel has issued a consensus document.
Defining a new class of HF
“Part of the impetus of this was to bring attention to what we think is a new class of heart failure, and it requires different treatment modalities and different ways of thinking about it,” expert panel member, cardiologist-in-chief at Barnes Jewish Hospital in St. Louis, said in an interview. “It’s a newly discovered HF biology about which we know very little and it’s very confusing to just go on the ejection fraction alone.”
The panel, led by, of Northwestern University, Chicago, recommends three components for a working definition of HFrecEF: 1) documentation of a decreased left ventricle ejection fraction (LVEF) of less than 40% at baseline; 2) a 10% or greater absolute improvement in LVEF; and 3) a second measurement of LVEF >40%.
“We try to give it a nomenclature that clearly indicates what it is,” Dr. Mann said. “There has been a lot of confusing terminology.” Among the terms the panel calls out in the lexicon of modestly recovered EF, in addition to HFrecEF, are HF improved EF, HF with preserved EF (HFpEF), borderline HFpEF and HF with mid-range EF (HFmrEF).
The panel also recommends that guideline-based medical and device therapies for HFrecEF should continue indefinitely until there’s a better understanding of the biology and clinical epidemiology of HFrecEF, and that these patients should have close clinical follow-up because of the high risk of HF relapse.
Determining EF’s ‘trajectory’
The findings presented in the statement should help cardiologists distinguish HFrecEF from HFpEF, Dr. Mann noted. “Because EF is moving, we also have to emphasize the importance of following the trajectory of EF,” he said. “It’s not enough to know where the EF is; you have to know where it came from – if it had been from a higher number or a lower number – because that will help inform you about the patient’s disease.”
In that regard, the panel states that the level of change in LVEF – the “trajectory” – will provide clues to the nature and extent of myocardial injury, degree and duration of LV remodeling, and the type of therapy that’s indicated. Clinicians should consider HFmrEF, a description the European Society of Cardiology has endorsed, as an entity different from HFrecEF without data on LVEF trajectory.
The statement delves into the biology of HFrecEF, defining reverse LV remodeling as the restoration of some normalization to cardiac myocyte size and LV chamber geometry that results in a leftward shift toward normalization of end-diastolic pressure volume. The panel also noted that cardiac remodeling in reverse LV remodeling and recovery of LV function is bidirectional and involves multiple molecular and cellular changes that contribute to changes in the heart’s size, shape and function, and explains the role gene expression has in HF-related LV changes.
The statement explores the recovery of LV function, noting that spontaneous recovery often occurs when the cause of the myocardial dysfunction resolves. Common causes are chronic tachycardia and thyroid disease.
That panel noted that “super responders” to cardiac resynchronization therapy can provide insight into HFrecEF. Favorable responders include women, patients with nonischemic HF, very wide ECG ventricular depolarization wavelength with left-bundle branch block morphology, and dyssynchrony on ECG.
The panel states that, “regardless of the definition of HFrecEF,” the evidence suggests that younger patients, women, and those with nonischemic disease, shorter disease duration, and relatively few comorbidities are more likely to recover LVEF – and their outcomes are typically better than those of patients with HF reduced EF (HFrEF) and HFpEF.
Clinicians should bear in mind, however, that patients on guideline-directed medical therapy (GDMT) who achieve complete normalization of LV structure and function are prone to recurrent LV dysfunction and HF. The panel explored the role of potential treatment for three different etiologies of HF. Little is known about Takotsubo cardiomyopathy, considered a transient form of LV dysfunction, in terms of how many of these patients will develop HFrEF or if they’ll benefit from GDMT. Alcohol-induced cardiomyopathy patients should continue on medical therapy even if they have HFrecEF, as should patients with fulminant and nonfulminant myocarditis.