Transient versus persistent improved ejection fraction in non-ischaemic dilated 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.