Characterization of heart failure patients with mid-range left ventricular ejection fraction—a report from the CHART-2 Study

Background: The new category of heart failure (HF), HF with mid-range left ventricular ejection fraction (LVEF) (HFmrEF), has recently been proposed. However, the clinical features of HFmrEF, with reference to HF with preserved LVEF (HFpEF) and HF with reduced LVEF (HFrEF) in the same HF cohort, remain to be fully examined. Methods and results: In the Chronic Heart Failure Analysis and Registry in the Tohoku District-2 Study, we examined 3480 consecutive HF patients with echocardiography data consisting of 2154 HFpEF (LVEF ≥50%), 596 HFmrEF (LVEF 40–49%) and 730 HFrEF (LVEF <40%). While clinical characteristics and prognostic factors of HFmrEF were intermediate between HFpEF and HFrEF, prognosis of HFmrEF resembled HFpEF and the prognostic impact of cardiovascular medications in HFmrEF resembled that of HFrEF. Analysis of LVEF transition among the three groups revealed that HFmrEF and HFrEF dynamically transitioned to other categories, especially within 1 year, whereas HFpEF did not; HFmrEF at registration transitioned to HFpEF and HFrEF by 44% and 16% at 1 year, and 45% and 21% at 3 years, respectively. Landmark analysis demonstrated that, regardless of HF stages at registration, HFmrEF patients at 1 year had mortality comparable to that of HFpEF patients, which was better than HFrEF patients, but HFmrEF patients at registration had increased mortality when transitioned to HFrEF at 1 year. Conclusions: These results indicate that clinical characteristics of HFmrEF are intermediate between HFpEF and HFrEF and that HFmrEF dynamically transitions to HFpEF or HFrEF, especially within 1 year, suggesting that HFmrEF represents a transitional status or an overlap zone between HFpEF and HFrEF, rather than an independent entity of HF.