Abstract: A 12-year-old Husky had fainted, vomited, and diarrhea the day before seeing a doctor, and was given pimobendan for the treatment in another hospital. In order to diagnose and treat the dog, clinical examination, laboratory examination（blood routine examination, blood biochemical index examination, blood gas examination, rapid detection of canine C-reactive protein）,X-ray examination, ECG examination and other methods were used for the diagnosis, and the treatment was carried out. The results showed that the dog had Ⅲ degree atrioventricular block complicated with heart failure and renal failure. The dog got better after 5 days of continuous treatment by adopting the principle of simultaneous treatment of the primary disease and secondary disease, but due to the lack of continuous treatment, the dog eventually died. The results suggested that when atrioventricular block complicated with other diseases, diagnosis and treatment needed to be considered in conjunction with ECG and other examinations to improve the survival rate of diseased animals within limited conditions.