Background: Inconsistency of treatment response in cats with obstructive hypertrophic cardiomyopathy is well recognized. We hypothesized that the difference in response to beta-blockers may be caused by myocardial functional abnormalities. This study was designed to compare myocardial function in cats with obstructive hypertrophic cardiomyopathy with and without response to beta-blockers. Twenty-one, client-owned, hypertrophic cardiomyopathy cats treated with carvedilol were analyzed. After carvedilol treatment, cats with decreased left ventricular outflow tract velocity were categorized as responders (n = 10); those exhibiting no response (no decrease in the left ventricular outflow tract velocity) were categorized as non-responders (n = 11). The cats were examined using layer-specific assessment of the myocardial function (whole, endocardial, and epicardial layers) longitudinally and circumferentially by two-dimensional speckle-tracking echocardiography, before and after carvedilol treatment. Results: The non-responder cats had a significantly higher age, end-diastolic left ventricular posterior-wall thickness, peak velocity of left ventricular outflow tract, and dose of carvedilol than the responders (p = 0.04, p < 0.01, p < 0.01, and p < 0.01, respectively). The circumferential strain in the epicardial layer was lower and circumferential endocardial to epicardial strain ratio was higher in non-responders than responders (p < 0.001 and p = 0.006). According to the multivariate analysis, circumferential strain in the epicardial layer was the only independent correlate of treatment response with carvedilol. Conclusions: Myocardial function, assessed by two-dimensional speckle-tracking echocardiography, differed in cats with hypertrophic cardiomyopathy with and without response to beta-blockers. The determination of layer-specific myocardial function may facilitate detailed pathophysiologic assessment and treatment response in cats with hypertrophic cardiomyopathy.

A 1-year-old female Akita dog was referred for intermittent regurgitation. Computed tomographic angiography (CTA) showed an aberrant right subclavian artery (ARSA), resulting in constriction of the esophagus. After surgical ligation of the ARSA, CTA showed that the ARSA was not enhanced by contrast medium, and that sufficient collateral circulation of the right forelimb was supplied through the vertebral artery. Furthermore, the right and left vertebral arteries merged into the basilar artery at the level of the atlas, and no abnormal expansion of the ventral spinal artery was observed. Overall, we demonstrated the importance of post-surgical CTA for identification of surgical complications, including the formation of abnormal vessel alterations.

Beta-blockers are used to treat cats with hypertrophic obstructive cardiomyopathy (HOCM). However, there are various hemodynamic responses to beta-blockers. This retrospective study aimed to explore the relationship between the response to carvedilol and the presence of geometric abnormalities. Medical records were reviewed for 16 cats diagnosed with HOCM. Cats were divided into two groups based on the velocity of the left-ventricular outflow-tract after carvedilol treatment (responder: eight cats, non-responder: eight cats). Baseline intergroup comparison revealed that anterior mitral valve leaflet length and diastolic left-ventricular posterior-wall thickness were significantly greater in the non-responder group. Longer anterior mitral valve leaflet and thicker left-ventricular posterior-wall may cause poor response to carvedilol. Thus, these properties may predict a lack of response to carvedilol therapy.

A 9-year-old male intact domestic cat weighing 4.6 kg was referred for tachypnea. A large mass was visible in computed tomography (CT) scans of the thoracic cavity. A histopathological evaluation of the mass was consistent with thymoma. The cat was treated with 2 × 8 Gy intensity modulated radiation therapy and sulfoquinovosyl acyl propanediol (SQAP). Post radiation therapy (RT), the tumor structure appeared cystic in the CT, and the tumor volume decreased by approximately 80% after aspiration than that before aspiration. The tumor was removed surgically. RT treatment with SQAP made it possible to treat the thymoma with a low total radiation dose.

This prospective crossover study compared the effects of intramuscular administration of medetomidine for sedation on parameters of the abdominal vascular system, measured by enhancement computed tomography (CT), to those of propofol-induced sevoflurane maintenance anesthesia, as a control, in five clinically healthy adult male beagle dogs (11.4–12.8 kg). Each animal underwent both protocols at a 1-week interval. The enhancement (HU) and time to peak enhancement on CT were measured for the aorta (AO), caudal vena cava (CVC), portal vein (PV), and hepatic parenchyma (HP). The contrast effects in the AO, PV, and HP were significantly delayed under medetomidine sedation compared to the control anesthesia protocol. Particularly, the contrast effect in the PV and HP was significantly delayed under sedation, appearing approximately 1 min after contrast medium injection. This delay likely reflects the peripheral vasoconstrictive effect of medetomidine. We noted a generally early high contrast enhancement of the CVC under medetomidine sedation, likely contributed by the induced bradycardia. Therefore, findings obtained on contrast enhancement CT under medetomidine sedation may be different from those obtained under propofol-induced sevoflurane maintenance anesthesia. These differences are important to consider when using the findings to inform diagnosis.