When the heart is always dull, it may be caused by the following reasons: 1, such as left chest wall diseases, including acute dermatitis, subcutaneous cellulitis, herpes zoster, epidemic chest pain, myositis, non-suppurative intercostalitis, costal neuritis, rib fracture, multiple leukemia, multiple myeloma, etc. 2, cardiovascular diseases, such as angina pectoris, acute myocardial infarction, myocarditis, acute pericarditis, or mitral valve, aortic aneurysm, aortic sinus aneurysm rupture, pulmonary embolism, pulmonary hypertension, cardiac neurosis. 3, respiratory diseases, including pleurisy, pleural tumor, spontaneous pneumothorax, pneumonia, acute bronchitis. 4. Mediastinal diseases, including mediastinitis, mediastinal tumors, esophagitis, hiatal hernia, esophageal cancer, etc. 5, subphrenic abscess, liver abscess, spleen embolism, these can all be caused.