This is an exploratory study to evaluate lung ultrasound as a method for measuring extravascular lung water in stabilized patients during hospitalization for ADHF. Subjects who have been stabilized following admission for ADHF and capable of lying supine will be evaluated by lung ultrasound to determine the degree of lung congestion as measured by the total B-line score. Since different patients may require different degrees of postural change and/or other maneuvers (e.g., leg elevation or exercise) to induce B-line increments, a tailored sequential protocol will be employed to define which maneuvers are sufficient for each patient.