Abstract Funding Acknowledgements Type of funding sources: None. Introduction Heart failure (HF) is a frequent complication of acute coronary syndromes (ACS). However, 5-15% of patients admitted with suspected acute myocardial infarction have no significant lesions on coronary angiography (>50%). Contrary to initial beliefs, MINOCA is not a benign disease, given that mortality and incidence of MACE is similar to ACS. Objective To evaluate predictors and prognosis of HF in the setting of MINOCA. Methods Based on a multicenter retrospective study, data collected from admissions between 2013 and 2020. Patients (pts) without data on cardiovascular history or uncompleted clinical data were excluded. Pts were divided in 2 groups (G): GA – pts without HF; GB - pts with HF during hospitalization. Results HF occurred in 63 (5.2%) out of 1218 pts with MINOCA. There were no differences between G regarding gender (p=0.779). GB pts were older (72±10 vs 65±13, p<0.001), had higher rates of arterial hypertension (88.9% vs 68.7%, p<0.001), diabetes (45% vs 27.5%, p=0.003), valvular disease (15.8% vs 2.1%, p<0.001), previous HF history (17.2% vs 6.2%, p=0.004), kidney dysfunction (15.1% vs 4.6%, p=0.006) and dementia (8.8% vs 0.7%, p<0.001). GA had higher rates of smoking habits (22.4% vs 3.3%, p<0.001). GB had higher heart rate at admission (92±25 vs 75±17, p<0.001), and higher rates of KK>1 (71.4% vs 6.3&, p<0.001), atrial fibrillation (25.5% vs 7.9%, p<0.001) and left branch bundle block (LBBB) (8.7% vs 1.4%, p=0.007). GB presented higher rates of kidney dysfunction (creatinine>2.0mg/dL) at admission (20.8% vs 4.8%, p<0.001)) and during hospital stay (31.6% vs 9.8%, p<0.001), lower haemoglobin levels at admission (13±1.8 vs 13.8±1.8, p=0.008) and during hospital stay (11.1±2.4 vs 12.7±1.8, p<0.001), higher BNP levels (BNP>400pg/ml) (100% vs 18.1%, p<0.001), and higher rates of left ventricle systolic dysfunction (LVEF<50%) (55.6% vs 17.6%, p<0.001). Logistic regression confirmed that KK>1 (p<0.001, OR 37.4, CI 13.6-102.7), LBBB (p=0.005, OR 10.1, CI 2.0-51.0), LV dysfunction (p=0.002, OR 8.3, CI 2.1-32.1) and smoking (p=0.046, OR 0.096, CI 0.01-0.96) were predictors of HF in the setting of MINOCA. Survival analysis confirmed GA had better prognosis regarding 1 year mortality compared to GB (p<0.001). Conclusion As expected, HF in the setting of MINOCA is associated with poorer prognosis. Several features may help predict the HF occurrence during hospitalizations, allowing an earlier treatment.