Pulmonary hypertension (PH) results from multiple disease processes and is most common in older, small-breed dogs. Clinical presentation includes cough, exercise intolerance, respiratory distress, and/or syncope. These clinical signs can be confused with a primary respiratory pathology and/or congestive heart failure. In humans, radiographic findings for PH can include patchy pulmonary edema and radiographic infiltrates. In dogs, diagnosis is made by echocardiography.