It depends on what disease causes pulmonary hypertension. There are several common causes of pulmonary hypertension, one of which is a pathological change in the pulmonary artery itself. Early on, there may be signs of mild increases in pulmonary artery pressure, possibly accompanied by slight right heart dysfunction. At this stage, symptoms such as mild hypotension and hypoxia might occur, manifesting as dizziness and fatigue. If the pulmonary hypertension is due to a disease of the lungs themselves, such as changes in the lung interstitium, then early symptoms of hypoxia will be more apparent, with chest tightness, slight breathing difficulties, and feelings of suffocation. If pulmonary hypertension is caused by conditions such as pulmonary embolism—specifically, an embolism in a smaller branch—the increase in pulmonary artery pressure may not be significant and will also be mild. This may be accompanied by a slight drop in blood pressure and mild breathing difficulties; however, because it is mild pulmonary hypertension, these symptoms are not severe and might include slight respiratory difficulty, mild chest tightness, shortness of breath, and mild dizziness. Therefore, early symptoms of pulmonary hypertension are typically not pronounced and generally do not attract special attention from patients.