Introduction: Despite different ultrasound parameters, left ventricular filling pressures (LVFP) assessment remains inconclusive in some cases. We aimed to determine the contribution of left atrial strain (LAS) in estimating LVFP in patients suspected of having heart failure with preserved ejection fraction (HFpEF). Methods: This was a monocentric study, carried out in the cardiology department of the Interior Security Forces Hospital of Marsa, between October 2021 and March 2022. Patients had a physical examination, a biological assessment and an ultrasound examination at rest and, if necessary, during exercise. We investigated the performance of LAS components (Peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS) and conduit function (FnC) in predicting LVFP rising. Results: We enrolled 73 patients. The mean age was 61 ± 12 years old with a female predominance (57.5%). The median PALS was 29.3% [21.4-32.4]. The mean PACS and FnC values were 13.4% ±4.9 and 13.7% ±4.7, respectively. patients were categorized into two finals groups according to LVFP: Group A= high LVFP at rest or during exercise (25=34%) and Group B= not-high LVFP at rest and during exercise (48=66%). Patients with high LVFP, had lower LAS parameters and higher NT-Pro BNP levels. LAS had negative correlations with the E/e' ratio and NT-Pro BNP. PALS was an independent predictor of LVFP raising (HR= 0.711; 95% CI: 0.513-0.986; p= 0.041). Conclusion: LAS is a simple, reproducible and sensitive ultrasound parameter for the diagnosis of HFpEF.