Aim. To assess the prognostic value of left atrial reservoir strain for predicting the risk of major adverse cardiovascular events in patients with type 2 diabetes (T2D) and intermediate probability of heart failure with preserved ejection fraction (HFpEF) over a 1-year follow-up period. Material and methods. A prospective study initially screened 164 patients with T2D (mean age 61±8 years) presenting with dyspnea and preserved left ventricular ejection fraction (≥50%). Using the HFA-PEFF score: HFpEF was considered unlikely with ≤1 point and confirmed with ≥5 points. The final study cohort comprised 58 patients with intermediate HF probability (2-4 points). These patients underwent standard clinical assessment, including laboratory and instrumental tests, as well as diastolic stress echocardiography (DSE) with physical exercise on a horizontal bicycle ergometer. A positive DSE result was defined as either: 1) an increase in E/e’ ratio ≥15 during exercise (2 points), or 2) an increase in E/e’≥15 accompanied by tricuspid regurgitation velocity >3.4 m/s (3 points). Left atrial strain (LAS) was assessed using speckle-tracking echocardiography with focus on reservoir function, with abnormal values defined as ≤18%. Results. According to DSE, 29.3% of patients had a positive result, confirming a diagnosis of heart failure with preserved ejection fraction (HFpEF). This group exhibited significantly lower LAS values both at rest and during exercise. Reduced LAS during exercise was correlated with increased left ventricular filling pressure. Furthermore, LAS demonstrated independent prognostic value in assessing the risk of adverse events. Kaplan-Meier analysis revealed a statistically significant association between LAS ≤18% and the risk of reaching the composite endpoint in the HFpEF group (Log Rank = 14.72; p <0,001). Conclusion. In patients with type 2 diabetes and intermediate HFpEF probability, reduced left atrial reservoir strain (≤18%) is a significant predictor of adverse cardiovascular events within a 1-year follow-up period. © 2025, Stolichnaya Izdatelskaya Kompaniya. All rights reserved.