Responsibility for the diagnosis and management of disorders of the pulmonary circulation has become the shared domain of the pulmonologist, cardiologist, surgeon, radiologist, pathologist, and, perhaps most important of all, the internist. It is the general internist who is most likely to care for the majority of patients with lung diseases that secondarily give rise to pulmonary heart disease, and it is the internist who will first evaluate the patient with primary pulmonary hyperten- sion or recurrent pulmonary thromboembolism who presents with nonspecific complaints and may manifest...