The 2016 ESC Heart Failure Guidelines introduced the term of Heart Failure with mid-range ejection fraction (HFmrEF) for patients with an ejection fraction between 40 and 49%. This group was identified as lacking information about characteristics, pathophysiology and treatment and was highlighted as a priority for research.
We aimed to characterise HFmrEF demographic and CMR imaging characteristics, comparing to those of heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF).
We prospectively recruited 200 patients with heart failure of unknown origin and no symptoms or history of coronary disease. Patients underwent clinical assessment, haematocrit assessment and adenosine stress perfusion CMR (Siemens 3T with Gadgetron) including inline T1 mapping, myocardial blood flow (MBF) mapping and late gadolinium enhancement. Patients with inducible regional ischaemia or myocardial infarction (n=38) were excluded from further analysis.
Patients with HFmrEF were more commonly female and used less diuretic compared to HFrEF. The cardiac phenotype of HFmrEF was of intermediate (HFpEF < HFmrEF < HFrEF) left ventricular (LV) indexed end diastolic volume, native T1 and ECV. Stress MBF and myocardial perfusion reserve were higher in HFmrEF compared to HFrEF while LV indexed mass was reduced; there was no significant difference to HFpEF.
Patients with HFmrEF have intermediate tissue characteristics compared with HFpEF and HFrEF. Myocardial perfusion in HFmrEF is preserved compared with HFrEF. These findings help understand differences in pathophysiology and suggest treatment options for these 3 groups.