If a patient experiences shortness of breath, it is not necessarily a clinical symptom or reaction to heart failure. Shortness of breath refers to weakness in breathing or self-induced dyspnea and insufficient ventilation flow, which is usually related to respiratory system diseases, circulatory system diseases, endocrine metabolic diseases, and common circulatory system diseases such as coronary heart disease, unstable angina pectoris, myocarditis, pericarditis, hypertensive heart disease, and rheumatic cardiomyopathy. Various arrhythmias caused by the above-mentioned factors or various causes of heart failure can cause chest tightness and shortness of breath, so it is not necessarily heart failure that causes shortness of breath. Respiratory system diseases, often in chronic pulmonary insufficiency, such as chronic pulmonary hypertension caused by pulmonary insufficiency will also have clinical symptoms of shortness of breath. Some endocrine metabolic disorders, such as thyroid dysfunction, may also cause shortness of breath.