The symptoms of pulmonary arterial hypertension are varied. In the early stages when pulmonary cardiac function is compensatory, the symptoms mainly include cough, phlegm, shortness of breath, difficulty breathing, and fatigue. Later, when pulmonary cardiac function becomes decompensated, symptoms of respiratory failure and right heart failure may occur. In cases of right heart failure, symptoms mainly manifest as systemic circulatory congestion, including visceral nausea, vomiting, palpitations, and pronounced shortness of breath. In respiratory failure, particularly pulmonary hypertension caused by pulmonary heart disease, symptoms like drowsiness, confusion, and gaze fixation, which are typical of pulmonary encephalopathy, may occur. Therefore, the symptoms of pulmonary arterial hypertension are diverse.