Cardiopulmonary Exercise Testing with Echocardiography to Identify Mechanisms of Unexplained Dyspnea

Little data is available about the pathophysiological mechanisms of unexplained dyspnea and their clinical meaning. Consecutive patients with unexplained dyspnea underwent prospective standardized cardiopulmonary exercise testing with echocardiography (CPETecho). Patients were grouped as having normal exercise capacity (peak VO2 > 80% with respiratory exchange [RER] > 1.05), reduced exercise capacity (peak VO2 ≤ 80% with RER > 1.05), or a...