Fussing Over the Middle Child
Heart Failure With Mid-Range Ejection Fraction
This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
In 2014, we dubbed heart failure (HF) with mid-range ejection fraction (EF) of 40% to 50% (HFmrEF) as the “middle child” in HF—unloved and neglected in contrast to the well-behaved older sibling (HF with reduced EF [HFrEF]) and the somewhat more turbulent youngest child (HF with preserved EF [HFpEF]).1 In 2016, HFmrEF achieved recognition in the European Society of Cardiology’s HF Guidelines. The specified aim for adopting the nomenclature was to “stimulate research into the underlying characteristics, pathophysiology and treatment of this group of patients.” This recognition was certainly an improvement from dismissing the EF 40% to 50% range as a grey zone, as done previously, and has indeed led to greater attention being paid to this group of patients. Because HFmrEF represents almost one fifth of the HF population, this fussing appears warranted. But have we gone too far?
Historically, most HF clinical trials published after 1990 selected patients based on EF and showed survival benefit only in patients with EF <35% to 40%; this finding led to the broad agreement that HFrEF should be defined using the 40% cutoff. At the time, HF with higher EF was referred to as “diastolic HF,” and implicit in this term was the much debated concept …