A 22-Year-Old Woman With Unexplained Dyspnea

Abstract

(CHEST 2009; 136:867–876) Abbreviations: AVC aortic valve closure; cGMP cyclic guanosine monophosphate; Dlco diffusing capacity of the lung for carbon monoxide; LV left ventricle/ventricular; MVO mitral valve opening; NO nitric oxide; PAP pulmonary artery pressure; PDE phosphodiesterase; RHC right heart catheterization; RV right ventricle/ventricular; TVO tricuspid valve opening Editor’s note: In this series, interactive diagrams are an important part of each article and are referred to throughout. You can access these online at [http:// www.chestjournal.org/content/136/3/867.full]. Included with the diagrams are “Show Me” videos, animated narrations that walk you through the main points of each diagram. The first time you access the online material, you may be asked to update your Web browser’s Flash Player plugin; this will enable you to view the diagrams as intended. If you are not automatically prompted to update the plugin and you have any problems using the diagrams, you can download the latest version of the Flash Player by visiting http://www.adobe.com/go/getflash. U nexplained dyspnea represents one of the common reasons for referral to a chest physician. The etiology can lie within multiple organ systems, and its evaluation requires a keen understanding of the underlying physiology. In this case presentation, we review one etiology of unexplained dyspnea and employ the “Interactive Physiology Grand Rounds” approach to address the basic physiologic mechanisms of this disease. We pay specific attention to the hemodynamic complications and complex relationships between right and left ventricular (LV) function that are at play in this disease, and use interactive diagrams to illustrate key concepts. Case Presentation