Background. There are currently few reported studies on the use of third generation β-blocker carvedilol in cats. This report presents the cardiovascular effects of carvedilol in seven healthy adult cats.

Materials and methods. Placebo or carvedilol (0.1, 0.2, or 0.4 mg/kg) was administered PO followed by isoproterenol infusion (0.04, 0.08, 0.16 µg/kg/min) 0, 3, 6, 12, and 24 h. During the isoproterenol infusion, heart rate (HR) and mean arterial pressure (MAP) were measured via a catheter inserted in the femoral artery. LV dP/dt was calculated by measuring the MAP and left ventricular (LV) pressure during infusion of isoproterenol (0.08 µg/kg/min) 3 h after administering 0.1 or 0.2 mg/kg carvedilol.

Results. Significant differences (p < 0.05) in the blocking effect of carvedilol were observed up to 12 h after the administration of 0.1 mg/kg of carvedilol and 24 h after the administration of 0.2 and 0.4 mg/kg of carvedilol. The elevation of HR and LV dP/dt in response to isoproterenol were suppressed three hours after the administration of 0.2 mg/kg carvedilol. There was no significant difference in the change in MAP.

Conclusion. Carvedilol at 0.2 or more mg/kg/day per os successfully blocked the β-adrenergic stimulus for 24 h in healthy conscious cats.

A 9-year-old male Jack Russell terrier presented to the JASMINE veterinary cardiovascular medical center for evaluation of a right atrial cardiac mass. He was suffering from dyspnea due to ascites and syncope. Physical examination showed abdominal distension and edema of the legs. No metastatic finding was observed in thoracic radiography, and abdominal radiography suggested ascites. Echocardiography revealed a right atrial mass, tricuspid regurgitation, reduction of right ventricular volume, and mitral valve regurgitation. We performed surgical debulking to improve right-sided congestive heart failure, together with mitral valve repair to prevent mitral valve regurgitation. During the operation, the tumor was found to adhere to the right atrial wall and atrial septum. Invasion of the tumor to the anterior and posterior vena cava was also observed. Bleeding was found in the middle lobe of the right lung on thoracotomy. Histopathological examination revealed that the right atrial mass was hemangiosarcoma and the bleeding trace in the lung was an early metastatic lesion. After pathological diagnosis, adjuvant chemotherapy with doxorubicin was started. The clinical signs improved temporarily and good QOL was maintained. At 50 days after surgery, ascites was detected, and pleural effusion appeared on the 57th postoperative day. Although improvement of respiratory condition was obtained by draining the pleural effusion, he died after collapsing on the 58th postsurgical day. The patient was able to maintain good QOL after surgery until ascites was again observed. In this case of right heart failure due to a mass in the right atrium, surgical debulking of the tumor was useful to temporarily improve right-sided congestive heart failure.

An 11-year-old, hound mixed breed dog weighing 18.5 kg was diagnosed with mitral valve insufficiency in private veterinary hospital in France. The dog was referred for mitral valve repair surgery at JASMINE Veterinary Cardiovascular Medical Center. After mitral valve repair, severe hepatic enzyme elevation was observed during the hospitalization period. Those hepatic enzyme elevation were suspected the cause of hepatitis by postoperative drug side effects or thromboembolism were suspected. The side effect of amlodipine could have contributed to the increase in hepatic enzymes that concluded by diagnostic tests. Amlodipine was discontinued immediately and initiated symptomatic treatments, and then the hepatic enzymes have returned to normal range, with no relapse of hepatitis.