Heart failure with reduced ejection fraction: differences between atrial fibrillation and sinus rhythm

Background: Atrial fibrillation (AF) is a common comorbidity in heart failure with reduced ejection fraction (HFrEF), with prevalence ranging from 10% to 60%. While AF is generally associated with increased mortality in HF, its impact on HFrEF outcomes remains uncertain. This study evaluates clinical, laboratory and echocardiographic differences between HFrEF patients with and without AF. Methods: This study included 91 patients (Left ventricular ejection fraction<50%) admitted to Grodno State Cardiological Centre from January to November 2024. Patients were divided into two groups: 57 (63%) with AF (paroxysmal or persistent) and 34 (37%) with sinus rhythm (SR). Clinical, laboratory and echocardiographic data were analysed using STATISTICA 12.0. Results: AF patients had higher BMI (p=0.005) and obesity prevalence (62% vs 26%, p=0.001). Hypertension and diabetes rates were similar, but SR patients had more stable angina (53% vs 34%, p=0.03) and prior myocardial infarction (44% vs 26%, p=0.048). AF patients showed worse renal function (higher urea, creatinine and lower eGFR). Echocardiography revealed larger left (p=0.03) and right atria (p=0.017) in AF, while SR patients had a higher contractility index (p=0.032). Conclusions: HFrEF patients with SR more often had ischemic cardiomyopathy, while those with AF had a dilated or mixed origin, as reflected in atrial size and contractility differences.