Loop diuretics remain a cornerstone in the management of congestive HF. However, their limitations in efficacy and safety are well recognized. This randomized pilot study pro- vides initial evidence that monotherapy with the vasopressin receptor antagonist tolvaptan may be an effective alternative diuretic strategy for select patients in acute HF, although this study was unable to demonstrate superior efficacy compared with a well-established regimen of intravenous furosemide.16 This study was unique in design, as it evaluated tolvaptan as monotherapy in patients with HF that required hospitaliza- tion for decongestive therapy. Other studies with tolvaptan in HF have been limited to application as monotherapy in out- patients with chronic stable HF or as an adjunctive therapy to loop diuretics in the hospital setting.