In mitral stenosis, the left ventricular filling is reduced, and the mitral valve is lowered in late diastole. Secondly, the systolic period is shortened due to the reduced blood volume in the left ventricle, and the pressure in the left ventricle rises rapidly, causing the low mitral valve to suddenly tense and close, resulting in a high-pitched, crisp first heart sound that sounds like a clapping sound, often referred to as the clapper first heart sound. In complete atrioventricular block, the atria and ventricles beat independently of each other, creating an atrioventricular dissociation. When the atria and ventricles contract at the same time in a coupled fashion, the first heart sound is extremely loud and is often pictorially referred to as the cannon sound. The following diseases are the causes of the apical part of the first heart sound: 1, mitral stenosis mitral stenosis is due to a variety of reasons to the heart mitral valve structural changes, resulting in the mitral valve opening amplitude becomes smaller, restricted opening or obstruction, causing the left atrium blood flow obstruction, left ventricular blood volume decreased, left atrial pressure increased and a series of abnormal changes in cardiac structure and function. The etiology of the disease is most common in rheumatic, and it is more common in the northern region of China, mostly occurring in the age of 20-40 years, with more women than men. There is no specific cure for this disease, cardiac intervention and surgical treatment can be cured. 2, rheumatic mitral stenosis Rheumatic fever is the most common cause of clinical mitral stenosis. Rheumatic fever is the most common cause of clinical mitral stenosis. It is a heart disease left behind after acute rheumatic fever causing carditis with valve disease as the main heart disease, and it is a chronic rheumatic heart disease, in which the involvement of the mitral valve accounts for 95% to 98%, among which the simple mitral valve lesion accounts for 70% to 80%, and the mitral valve combined with aortic valve lesion accounts for 20% to 30%; it exists in combination with the mitral valve or the aortic valve lesion. In recent years, due to the strengthening of the prevention and treatment of rheumatic fever, the incidence of rheumatic heart valve disease decreased significantly. 3, atrioventricular conduction block In the process of electrical excitation conduction of the heart, the electrical excitation conduction abnormality between the atria and the ventricles can lead to arrhythmia, so that the heart can’t contract and pump blood normally, which is called atrioventricular conduction block. AV block can occur in different parts of the atrioventricular node, the Hitchcock’s bundle, and the bundle branches. Depending on the degree of block, it can be categorized as first, second and third degree AV block. The clinical manifestations, prognosis and treatment of the three types of atrioventricular block are different. Atrial fibrillation (AF) is one of the most common arrhythmias in the elderly. It is an atrial rhythm in which the atria show disordered agitation and ineffective contraction, and it is an atrial rhythm disorder caused by the atrial-dominant refractory loops causing many small refractory loops, and it is very common in the elderly. It is seen in almost all organic heart diseases and can occur in non-organic heart diseases as well. Atrial fibrillation is highly prevalent, long lasting, and can also cause serious complications such as heart failure and arterial embolism. It leads to increased disability or mortality in patients and has a serious impact on human health.