Appropriate dosages of cilostazol have not been studied in veterinary patients, and the degrees of heart rate (HR) increase have not been studied in dogs administered cilostazol. Therefore, this study aimed to investigate the degrees of HR increase in healthy dogs administered cilostazol. Thirty healthy beagle dogs (15 males and 15 females; age, 5–8 years) were divided into 3 groups of 10 dogs each and orally administered 2.5, 5, or 10 mg/kg cilostazol (twice a day at 8:00 AM and 8:00 PM for 10 days). Higher HR increases were seen in the 5 mg/kg group than in the 2.5 mg/kg group at all time points except 7:00 AM, 9:00 AM, 1:00 PM, and 4:00 PM (P<0.01). Higher HR increases were also observed in the 10 mg/kg group than in the 2.5 mg/kg group at all time points except 4:00 PM (P<0.01). The 10 mg/kg group showed higher HR increases than the 5 mg/kg group at all time points except 6:00 AM, 7:00 AM, 6:00 PM, and 7:00 PM (P<0.05 for 4:00 PM and 5:00 PM; P<0.01 for the other time points). These results together show that the HR of healthy dogs increased in a dose-dependent manner after cilostazol administration twice a day at doses of 5 to 10 mg/kg. These results provide a useful basis for choosing cilostazol in the treatment of bradyarrhythmia in dogs.

The pancreas is believed to be vulnerable to hypoperfusion. In dogs with acute pancreatitis, pancreatic ischemia due to heart failure can worsen the condition. However, changes in pancreatic blood flow associated with decreased cardiac function have not been previously studied in dogs. Therefore, we aimed to identify and compare changes in pancreatic versus renal blood flow as a result of cardiac dysfunction. Seven dogs were subjected to rapid ventricular pacing to create heart failure models. Noninvasive blood pressure measurement, echocardiography, contrast-enhanced ultrasonography for pancreatic blood flow measurement, and para-aminohippuric acid clearance for renal blood flow measurement were performed before starting and at 2 and 4 weeks after starting the pacing. Left ventricular cardiac output and mean blood pressure decreased at 2 and 4 weeks after starting the pacing, and pancreatic blood flow decreased at 2 and 4 weeks after starting the pacing. However, renal blood flow did not change at 2 weeks but decreased 4 weeks after starting the pacing. Overall, this study demonstrated that reduced pancreatic blood flow due to cardiac dysfunction occurs, similar to renal blood flow. This suggests that decreased pancreatic blood flow is not unusual and may frequently occur in dogs with heart failure. The results of this study support the speculation that heart failure can exacerbate acute pancreatitis. Additionally, this study provides useful basic information for designing further studies to study this association.

The changes in intra-atrial blood coagulability of acute phase after development of atrial fibrillation (AF) have not been elucidated in human. In the present study, blood coagulability were examined in the intra-atrial and peripheral regions during the acute phase after development of rapid atrial pacing (RAP) in experimentally created model dog similar to AF, using Total Thrombus-formation Analysis System (T-TAS) that is capable of comprehensively evaluating thrombogenicity in the bloodstream in the microvascular channel. According to the results, both the coagulating function-evaluating time to +10 kPa (T 10 ) and occlusion time (OT) of the AR chip (chip for thrombus analysis mixed with coagulation and platelet) were significantly shortened in the atrial blood as early as 30 min after pacing (T 10 , 150.5 ± 40.5 s; OT, 212.4 ± 44.3 s) compared to the pre-pacing levels (T 10 , 194.5 ± 47.5 s; OT, 259.9 ± 49.5 s) ( P <0.05). The OT of PL chip (chip for platelet thrombus analysis) was significantly shortened 30 min after pacing (231.8 ± 57.6 s), compared to the pre-pacing level (289.5 ± 96.0 s) ( P <0.05). Meanwhile, none of T 10 and OT of AR and PL chips showed any significant changes in the peripheral blood. The study demonstrated increase of blood coagulability 30 min after development of RAP. While no significant changes were observed in the peripheral blood in the present study, the outcome suggested that the anti-thrombus treatments are better to be started early after AF even if coagulability of the peripheral blood shows no change.

No abstract

A 14-year-old intact male West Highland White Terrier weighing 6.9 kg was admitted to the Tokyo University of Agriculture and Technology Animal Medical Center with the complaint of syncope after showing signs of nausea during feeding. Sinus arrest induced by deglutition was confirmed using a Holter electrocardiography test. However, the clinical symptoms significantly improved after implantation of a permanent pacemaker. Seven months after implantation, the dog died from acute pancreatitis, a cause unrelated to the syncope. Immediately after its death, the heart, lungs, gastrointestinal tract, and other organs were dissected and examined histopathologically. The brain was also examined using magnetic resonance imaging. Examination results led to the diagnosis of swallowing-induced situational syncope.