A 7-year-old Golden Retriever with mild exercise intolerance and presence of an arrhythmia was referred to Nihon University. Electrocardiographic findings included wide QRS complexes, irregular R–R intervals, small irregular baseline undulations and no P waves. Thoracic radiography revealed a large mass of soft tissue opacity obliterating the cranial cardiac silhouette and the dilation of the pulmonary artery silhouette. Transthoracic echocardiography showed a type III pulmonary artery flow pattern, but it did not reveal the presence of a mass in the cranial mediastinum. Computed tomography angiography identified an enlarged right auricle that was consistent with a right auricular aneurysm in the region of the suspected mass. This case was therefore diagnosed with a right auricular aneurysm. These findings suggest that computed tomography angiography may be a useful diagnostic tool in the diagnosis of the right auricular aneurysm.
Six-year-old female intact mixed breed dog was referred to Azabu University Veterinary Teaching Hospital because of bradycardia. High-grade second-degree atrioventricular block (AV block) was diagnosed. Although the dog was completely asymptomatic and no previous history of cardiac events was noticed, the artificial cardiac pacemaker (AP) was implanted because high-grade second degree AV block may progress to third-degree AV block and left ventricular enlargement was noticed. However, left ventricular function deteriorated over time and left ventricular enlargement worsened. Dilated cardiomyopathy was suspected since worsening of LV enlargement and systolic function. Sixteen months after pacemaker implantation, the dog began to show exercise intolerance. It has been approximately four year at the time of writing, and the dog was medically managed.