Background: Left ventricular ejection fraction (LVEF) was known as a conventional predictor of heart failure (HF). However, early transmitral flow velocity (E)/early diastolic velocity of mitral annulus (E���) correlated well with LV end-diastolic pressure was an excellent predictor of adverse outcomes in patients with diastolic HF. This study was designed to determine clinical parameters influenced on the E/E��� ratio in HF patients with preserved ejection fraction (LVEF>50%). Methods: We conducted a retrospective analysis of collected data on 428 consecutive patients who had been hospitalized in CHF with a preserved ejection fraction between May 2006 and April 2009 at our centers. We assessed demographic (age, sex) and clinical characteristics and echocardiographic and laboratory findings. Results: The patients were divided into the 3 groups of group I (E/E��� ratio <8, 31 patients, mean age 67 yr, male 20), group II (8��� E/E��� ratio <15, 214 patients, mean age 69 yr, male 122), and group III (15��� E/E��� ratio, 183 patients, mean age 72 yr, male 76). There was higher incidence of female and older age. The patients in group III had higher left ventricular mass indes (LVMI). The level of lipoprotein and log proBNP in group III were significantly higher compared to those in group I. The estimated glomerular filtration rate in group III were significantly lower compared to those in group I. After adjustment for several significant parameters, using a multivariate logistic regression analysis, hemoglobin (adjusted p=0.000; odds ratio [OR] 0.613) and LVMI (adjusted p=0.003; OR 1.018) were important clinical parameters influenced on the E/E��� ratio in group III. Conclusions: In conclusion, hemoglobin and LV mass index were important clinical parameters influenced on the E/E��� ratio in HF patients with preserved ejection fraction (LVEF>50%).