Abstract
In three dogs with sinus bradycardia, the reasons for the development of sinus bradycardia were discussed on the basis of notifications and clinical findings. These cases were admitted to a veterinary hospital with individual clinical signs of persistent coughing (Case 1), a sudden onset of anorexia and vomiting (Case 2), and continuous diarrhea for 20 days (Case 3), respectively. All the cases showed bradycardia, marked depression, listlessness and blank expressions as the common findings. In view of the clinical signs, electrocardiographic findings or detailed questioning, sinus bradycardia observed in these cases was considered to have been caused by high vagal tone due to coughing (Case 1) and psychosomatic disease (Cases 2 and 3), respectively. Case 1 was given atropine sulfate orally, which established a normal heart rate and led to disappearance of coughing. The condition of Case 2, originating from uneasiness accompanying separation from the owner was resolved by his return home. In Case 3, all symptoms, including bradycardia, disappeared a few days after improvement of its surroundings.
