LVEF: left ventricular ejection fraction AF: atrial fibrillation HF: heart failure NDF: normal diastolic function IDT: indeterminate diastolic function/filling pressure

Ibon Rodriguez-Sanchez^1*Inaki Villanueva-Benito²Urko Agirre³Jose Juan Onaindia¹Alazne Urkullu¹Angela Cacicedo¹Alberto Ullate¹Idoia Bravo¹Jesus Florido-Perena¹Alberto Salcedo¹Sonia Velasco¹

• ¹Galdakao University Hospital, Biobizkaia Health Research Institute, Osakidetza, SPAIN, Galdakao, Spain
• ²Donostia University Hospital, Biodonostia Health Research Institute, Osakidetza, SPAIN., Donostia, Spain
• ³Kronikgune Institute for Health Service, Galdakao University Hospital, Osakidetza, REDISSEC, SPAIN, Barakaldo, Spain

Background: A limited number of studies have examined the prognostic significance of diastolic function in patients with preserved left ventricular ejection fraction (LVEF) in a general population referred for transthoracic echocardiography. Our aim was to assess the association between diastolic function and a combined event in which the left atrium plays a pivotal role, including heart failure (HF), atrial fibrillation (AF) and ischemic stroke. The study sought to determine the incremental value of left atrial reservoir strain (LARS) in risk stratification.We performed a retrospective analysis of 364 patients with preserved LVEF and sinus rhythm referred for transthoracic echocardiography and categorized them into four groups based on their diastolic function status according to the 2016 ASE/EACVI guidelines: normal diastolic function (NDF), indeterminate diastolic function and diastolic dysfunction with indeterminate filling pressure (IDT), grade 1 diastolic dysfunction (DD1), and diastolic dysfunction with elevated filling pressure (DD-EFP).The primary endpoint was a composite of HF, AF or ischemic stroke. LARS was measured by 2D speckle tracking. Clinical parameters, comorbidities and specific cardiac diseases were also assessed. Secondary endpoint was all-cause mortality.The mean follow-up period was 2.4 years. IDT and DD-EFP diastolic function status were independently associated with the combined event. The incorporation of LARS enhanced risk stratification, particularly in IDT patients, with a cutoff of ≤24% identifying a high-risk population. Patients classified as high risk, defined as those with DD-EFP and IDT with LARS≤24%, exhibited a notable event rate of 34% and 46%, 4 respectively. Diastolic function and LARS were not independently associated with allcause mortality.In patients with preserved LVEF and sinus rhythm, diastolic function is strongly and independently associated with the combined event of HF, AF, or ischemic stroke. LARS provides a valuable tool for improving risk stratification in this population.Patients at high risk (DD-EFP and IDT with LARS≤24%) demonstrated a significant event rate, underscoring the necessity for preventive measures. Diastolic function and LARS were not independently associated with all-cause mortality. Further studies are required to confirm these findings and validate the proposed approach.