Clinical characteristics and outcomes of patients with acute heart failure according to ejection fraction: analysis of the BREATHE registry

Background/Introduction Heart failure (HF) is a complex clinical syndrome that may occur across a broad spectrum of left ventricular ejection fraction (LVEF) values. Despite its growing epidemiological burden, data on clinical characteristics, in-hospital management, and long-term outcomes stratified by ejection fraction category remain limited, particularly in Latin American and lower-middle-income countries where access to care and disease profiles may differ substantially from high-income settings. Purpose To evaluate the clinical profile, in-hospital management, and 12-month outcomes of patients hospitalised with acute HF according to LVEF category, using data from the large prospective Brazilian BREATHE registry. Methods BREATHE was a prospective, multicentre, national registry enrolling consecutive patients hospitalised for acute HF across multiple Brazilian centres. Patients were stratified into three groups according to LVEF: reduced ejection fraction (HFrEF, ≤40%), mildly reduced ejection fraction (HFmrEF, 40–49%), and preserved ejection fraction (HFpEF, ≥50%). In-hospital management, haemodynamic profiles, laboratory parameters, and clinical outcomes at 12 months were systematically assessed and compared across groups. Results A total of 3,013 patients were included, with a median follow-up of 346 days. HFrEF was the most prevalent phenotype within the registry. Patients with HFpEF were significantly older, predominantly female, and exhibited a higher prevalence of hypertension and atrial fibrillation, whereas prior myocardial infarction was more frequent among those with HFrEF. Renal function was comparable across all groups; however, BNP/NT-proBNP levels were notably lower in HFpEF. A cold-and-wet haemodynamic profile on admission was more prevalent in HFrEF, suggesting greater initial clinical severity in this subgroup. Regarding aetiology, HFpEF was more commonly associated with hypertensive origin, while HFrEF showed a clear predominance of ischaemic aetiology. At 12 months of follow-up, no statistically significant differences were observed in all-cause mortality or hospital readmission rates across ejection fraction phenotypes. Conclusions In this large Brazilian prospective multicentre registry of acute HF, patients presented with markedly distinct clinical characteristics according to ejection fraction category; nevertheless, one-year prognosis was similarly unfavourable across all phenotypes. These findings highlight the persistently high burden of acute HF regardless of LVEF and underscore the urgent need for improvements in medical care and disease management strategies to reduce morbidity and mortality across all ejection fraction categories.