Transient versus persistent improved ejection fraction in non‐ischaemic dilated cardiomyopathy

Among the 460 patients with improved ejection fraction (impEF) (57% of the overall cohort), 271 (59%) exhibited a persistent impEF. Longitudinal trends of left ventricular ejection fraction (LVEF) clearly diverged according to outcome in patients with impEF. Patients who experienced the primary outcome (all‐cause death/heart transplantation/left ventricular assist device [D/HT/LVAD]) had a larger deterioration in LVEF (median nadir of LVEF 32%, interquartile range 25–42) compared to patients alive free from heart transplantation/left ventricular assist device (median nadir of LVEF 41%, interquartile range 35–49). NICM, non‐ischaemic cardiomyopathy. Aims The recent definition of heart failure with improved ejection fraction outlined the importance of the longitudinal assessment of left ventricular ejection fraction (LVEF). However, long‐term progression and outcomes of this subgroup are poorly explored. We sought to assess the LVEF trajectories and their correlations with outcome in non‐ischaemic dilated cardiomyopathy (NICM) with improved ejection fraction (impEF). Methods and results Consecutive NICM patients with baseline LVEF ≤40% enrolled in the Trieste Heart Muscle Disease Registry with ≥1 LVEF assessment after baseline were included. ImpEF was defined as a baseline LVEF ≤40%, and second evaluation showing both a ≥10% point increase from baseline LVEF and LVEF >40%. Transient impEF was defined by the documentation of recurrent LVEF ≤40% during follow‐up. The primary endpoint was a composite of all‐cause death, heart transplantation and left ventricular assist device (D/HT/LVAD). Among 800 patients, 460 (57%) had impEF (median time to improvement 13 months). Transient impEF was observed in 189 patients (41% of the overall impEF group) and was associated with higher risk of D/HT/LVAD compared with persistent impEF at multivariable analysis (hazard ratio 2.54; 95% confidence interval 1.60–4.04). The association of declining LVEF with the risk of D/HT/LVAD was non‐linear, with a steep increase up to 8% points reduction, then remaining stable. Conclusions In NICM, a 57% rate of impEF was observed. However, recurrent decline in LVEF was observed in ≈40% of impEF patients and it was associated with an increased risk of D/HT/LVAD.