Rationale for use of an exercise end point and design for the ADVANCE (A Dose evaluation of a Vasopressin ANtagonist in CHF patients undergoing Exercise) trial.

Background: Exercise intolerance is a primary characteristic of chronic congestive heart failure. Exercise testing is therefore widely used to evaluate the degree of functional impairment, prognosis of underlying cardiac disease, and response to treatment. Historically, studies that used exercise tolerance as an end point to evaluate the efficacy of pharmacologic interventions have been confounded by methodologic differences involving protocols, exercise end points, absence or misuse of gas exchange data, and study design.