Pulmonary hypertension is a common clinical condition with very complex causes, which can be induced by a variety of heart, lung, and pulmonary vascular diseases. When pulmonary hypertension occurs, because the resistance in the pulmonary circulation increases, the burden on the right heart increases, eventually leading to right heart failure, thus causing a series of clinical manifestations. During the disease course, pulmonary hypertension commonly shows progressive development. Currently, the diagnostic criteria for pulmonary hypertension are an average pulmonary artery pressure greater than 25 mmHg measured by right heart catheterization at sea level in a resting state, or greater than 30 mmHg during exercise. Additionally, diagnosing arteriogenic pulmonary hypertension requires, beyond the aforementioned criteria, that the pulmonary capillary wedge pressure or left ventricular end-diastolic pressure be less than 15 mmHg. The severity of pulmonary hypertension can be classified into mild, moderate, and severe stages based on resting mean pulmonary artery pressure levels. Mild is defined as 26 to 35 mmHg, moderate as 36 to 45 mmHg, and severe as greater than 45 mmHg. Echocardiography is the most important non-invasive examination method for assessing pulmonary hypertension, and it is recommended that a pulmonary artery systolic pressure greater than 40 mmHg be considered indicative of pulmonary hypertension according to echocardiographic standards.