Differential diagnosis of third-degree atrioventricular block is as follows: 1. Interference and disconnection, such as the formation of agitation in normal cardiomyocytes after one conduction, two similar agitations due to the longer period of incontinence, and the formation of the latter agitation and conduction, that is, interference. If the agitation generated by two different pacing points in parallel at the cardiac locus causes a series of interferences, it is called disjunction. Its electrocardiographic features are similar to those of conduction block patterns and need to be differentiated from them.2. Sinus block, the point of the sinus node cannot be traced out on a conventional electrocardiogram, so it is difficult to differentiate third-degree atrioventricular block from sinus arrest.3. Intra-atrial block, complete intra-atrial block needs to be distinguished from third-degree atrioventricular block, which is mainly characterized by the formation of afferent and efferent block around the localized atrial myocardium and causes The main feature is the formation of afferent and efferent block around the localized atrial muscle, causing atrial separation.