To compare the ability of the E/a' ratio and the recommended diastolic parameters in the American Society of Echocardiography (ASE) and the European Association of Cardiovascular Imaging (EACVI), in predicting a dominant diastolic pulmonary vein flow in patients with normal ejection fraction. We retrospectively evaluated the diastolic function according to the ASE/EACVI guidelines, the S/D ratio and the septal, lateral and average E/a' ratio in 293 unselected in-hospital patients, aged 39-86 years, in sinus rhythm and with no or mild valve disease, having a normal systolic function (EF > 50%). The S/D ratio had a positive association to septal, lateral and average E/a ratio (R = 0.25, 0.35 and 0.32). The association to average E/e' ratio, LA vol index and TR velocity was weak ( = 0.037, 0.033 and 0.087) and for e' velocity negatively. In patients with S/D ratio <1, septal, lateral, average E/a' ratio, average E/e ratio, LA vol index (<.001) and TR velocity (<.05) were significantly higher compared to patients with S/D ratio ≥1. No significant difference was seen in e' velocity. The septal, lateral and average E/a' ratio were significantly higher in patients with S/D ratio <1 regardless a normal or impaired diastolic function according to the ASE/EACVI guidelines (<.001). The ASE/EACVI algorithm detected 21 patients with S/D ratio <1 compared to 28 patients using average E/a' ratio with cut-off >14. E/a' ratio might be a useful new diastolic parameter in patients with a normal ejection fraction as it is more closely related to the S/D ratio than the established ASE/EACVI diastolic parameters.