The pathophysiologic interactions that link the heart and kidney are multiple and complex, and have been grouped under the umbrella term "cardiorenal syndrome." In the setting of acute decompensated heart failure, worsening renal function has been directly associated with poor clinical prognosis and complicates treatment. However, the pathophysiology underlying acute cardiorenal syndrome remains incompletely understood and treatment options remain limited. Traditionally, the development of worsening renal function in acute decompensated heart failure has been attributed to renal arterial underfilling due to reduced cardiac output or intravascular volume depletion. However, increasing data have expanded our understanding of the roles that venous congestion and intra-abdominal pressure play in driving renal injury, with important implications for therapeutic management and the development of novel renal-sparing therapies.