Regarding the diagnosis of heart failure, if a patient has underlying cardiovascular disease, such as diabetes, hypertension, or coronary artery disease. If they have shortness of breath, or shortness of breath that is more pronounced after activity, or even swelling of the lower limbs, and cannot lie down at night, they have to sit up to breathe more freely. In such patients, heart failure is highly suspected. The next step for such patients is to do some specific tests, such as cardiac ultrasound, to see if the heart failure is caused by heart valve disease or cardiomyopathy. Most of the patients can be screened out through cardiac ultrasound. Some patients are screened by coronary angiography to see if the heart failure is caused by coronary artery disease. Other patients should have an electrocardiogram to see if the heart failure is caused by arrhythmia, and further clarify the cause through ancillary tests.