Abstract Objectives The aims of the study were: (1) to determine the pattern of myocardial fibrosis assessed by delayed gadolinium enhancement cardiac MRI (DGE-CMRI) in patients with heart failure improved ejection fraction (HF-iEF) in an advanced heat failure clinic; and (2) to examine the dosage of beta-blocker and angiotensin converting enzyme inhibitor/ angiotensin receptor blockage/angiotensin neprilysin inhibitor (ACE-I/ARB/ARNI) in those patients. Methods HF-iEF was defined as patients with LVEF >40% with previously documented LVEF <35% at baseline. Results Among 312 consecutive patients with HF-rEF who were referred for an advanced HF clinic, 18% (56 patients) had HF-iEF within 12 months after referral. Of these, 84% (47 patients) had non-ischemic cardiomyopathy (CM); complete data on MRI for analysis were available for 25 of these patients (62%). Myocardial scar was found in 52% of patients with nonischemic CM (13 of 25). All patients with nonischemic CM had the myocardial scar of less than 10% of the total LV volume. Mid-wall DGE of the interventricular septum was the most common scar pattern. Among patients with HF-iEF, 36% (20 patients) were referred for heart transplant. Two patients with peripartum related and nonischemic etiologies were listed for heart transplant, and delisted 12 months after. No patient died during 1-year follow up. At 12 months, the mean LVEF change was +27±12%. Improvement of the LVEF to ≥50% occurred in 31 patients (55%). The percentage use of ACE-I/ARB/ARNI and beta-blocker was significantly increased, at 1-year-follow-up. Fourteen percent and 48% of patients achieved target dose of ACE-I/ARB/ARNI and beta-blocker, respectively. There was no significant association between myocardial scar pattern or extent and dosage of medical titration. Conclusions HF-iEF was present in 18% of patients with HF-rEF after 1-year follow-up in advanced heart failure clinic. Mid-wall DGE of the interventricular septum was the most common scar pattern in nonischemic HF-iEF. None of patients with nonischemic HF-iEF had myocardial scar >10% of the total LV volume. Improvement of LVEF to ≥50% occurred in approximately half of the study patients, and led to delisting patients from heart transplant waiting list. The majority of patients had recovery of the LVEF when the target dose of beta-blocker or ACE-I/ARB/ARNI had not been achieved during medical up-titration. Funding Acknowledgement Type of funding source: None