Atrioventricular block is a blockage of impulses during atrioventricular conduction. There are two types of block: incomplete and complete. The former includes first- and second-degree AV block, while the latter is also called third-degree AV block, and the block can be in the atrium, AV node, Hitchcock’s bundle and double bundle branches. In complete AV block, the temporal relationship between the atria and the ventricles is separated, and the atria lose their auxiliary pumping effect on ventricular contraction, resulting in a decrease in cardiac output. The following diseases are also causes of loss of atrial pumping of ventricular contraction: 1. complete atrioventricular block Complete atrioventricular block, also known as third-degree atrioventricular block, is caused by abnormal reduction in the conduction ability of a part of the atrioventricular conduction system, and all excitation from the atria cannot be transmitted downward. Complete atrioventricular separation. Acute myocardial infarction (AMI) refers to the acute necrosis of part of the myocardium due to persistent and severe myocardial ischemia. The clinical manifestations often include severe and persistent retrosternal pain, acute circulatory dysfunction, arrhythmias, cardiac failure, fever, elevated white blood cell count and serum myocardial injury marker enzymes, and progressive evolution of the electrocardiogram reflecting myocardial injury, ischemia and necrosis. According to the extent of infarction, myocardial infarction can be divided into two categories: transmural myocardial infarction and subendocardial myocardial infarction. Myocardial infarction can be divided into acute myocardial infarction and old myocardial infarction according to the process of lesion development. 3, myocarditis Myocarditis (myocarditis) is a limited or diffuse inflammation of the myocardium caused by various causes. Although some myocarditis is considered by some scholars to be secondary to cardiomyopathy because it can transition to congestive or restrictive cardiomyopathy at the end stage, myocarditis is, after all, a distinguishable type of disease in terms of pathogenesis. There are many causes of myocarditis, such as viruses, bacteria, fungi, parasites, immune reactions, and physical and chemical factors that can cause myocarditis. 4, heart disease Heart disease is a relatively common type of circulatory system disease. The circulatory system consists of the heart, blood vessels and the neurohumoral tissues that regulate blood circulation. Circulatory system diseases, also known as cardiovascular diseases, include diseases of all the above-mentioned tissues and organs, and are common in internal medicine, among which heart disease is the most common and can significantly affect the patient’s workforce.