The left branch of the heart generally refers to the left coronary artery of the heart, and the treatment for moderate to severe stenosis includes coronary stent implantation, coronary artery bypass grafting surgery and medication. 1. Coronary stenting: For patients with moderate-to-severe coronary stenosis, that is, patients with stenosis greater than 75%, it is recommended that patients undergo percutaneous coronary angiography + coronary stenting, so as to make the stenotic vessels expand and recanalize. 2. Coronary artery bypass surgery: also known as coronary artery bypass grafting, by taking one’s own blood vessels to establish a bypass, so that the blood bypasses the narrowed blood vessels to reach the myocardium, and improves myocardial ischemia. 3. Medication: For patients with coronary artery stenosis, regardless of whether or not they are treated surgically, they need to take secondary prevention medications for coronary artery disease. These include antiplatelet agents such as aspirin and clopidogrel, anti-atherosclerotic drugs such as atorvastatin, and other drugs to improve myocardial oxygen consumption such as metoprolol. Patients with cardiac stenosis are advised to seek timely medical consultation and treatment as prescribed by the doctor.