Introduction: This study described patients hospitalized for acute heart failure (AHF) in Japan who received intravenous (IV) diuretics and/or vasodilators as the initial therapy. Methods: The Japan Medical Data Vision database was used to identify adult patients hospitalized for AHF during 2013-2017, who were hemodynamically stable at presentation and treated with IV diuretics and/or IV vasodilators as initial therapy. Treatment patterns and use of cardiac rehabilitation, as well as outcomes (e.g., length of stay [LOS], in-hospital mortality, HFreadmission) were reported overall and by year of AHF hospitalization.Results: Of 30,360 patients (mean age = 80.0 years; 52.2% male), 87.0% were treated during the hospitalization with IV diuretics, 63.9% with IV vasodilators, and 13.8% with intensified therapies. On average, the duration of IV therapy was 10.6 days. Inhospital cardiac rehabilitation was utilized by 51.7% of the patients for 11.7 days on average. Mean LOS was 23.3 days, while in-hospital mortality and 30-day HF readmission post-discharge were 13.2 and 9.5%, respectively. Hospitalization outcomes remained stable between 2013 and 2017 despite important changes in AHF management such as a decrease in carperitide use (55.9-40.0% in 2017), and increases in use of tolvaptan (from 14.2% in 2013 to 31.3% in 2017) and of cardiac rehabilitation (from 43.2% in 2013 to 56.1% in 2017). Patients with intensified therapies had the longest IV therapy duration (mean 23.8 days vs. 5.5-9.9 days), the highest cardiac rehabilitation services use (60.2 vs. 38.3-57.0%), the longest LOS (mean 36.7 vs. 16.3-22.2 days), and the highest in-hospital mortality (37.4 vs. 3.1-12.4%) compared to the other treatment groups. Conclusions: Contemporary treatment for AHF hospitalization in Japan comprises a long duration of IV therapy followed by extended use of oral medications and in-hospital cardiac rehabilitation prior to discharge. Patients requiring intensified therapies had much longer LOS and higher in-hospital mortality.