Early detection of doxorubicin (DXR)-induced cardiomyopathy (DXR-ICM) is crucial to improve cancer patient outcomes and survival. In recent years, the intraventricular pressure gradient (IVPG) has been a breakthrough as a sensitive index to assess cardiac function. This study aimed to evaluate the usefulness of IVPG for the early detection of chemotherapy-related cardiac dysfunction. For this purpose, six dogs underwent conventional, speckle tracking, and color M-mode echocardiography concomitantly with pressure-and-volume analysis by conductance catheter. The cardiac function measurements were assessed before DXR administration (baseline, Pre), at the end of treatment protocol (Post), and at 1.5 years follow-up (Post2). The result showed a significant reduction in the left ventricular end-systolic pressure-volume (Emax: 4.4 ± 0.7, 6.1 ± 1.6 vs. 8.4 ± 0.8 mmHg/mL), total-IVPG (0.59 ± 0.12, 0.62 ± 0.15 vs. 0.86 ± 0.12 mmHg), and mid-IVPG (0.28 ± 0.12, 0.31 ± 0.11 vs. 0.48 ± 0.08 mmHg), respectively in Post2 and Post compared with the baseline (p < 0.05). Mid-to-apical IVPG was also reduced in Post2 compared with the baseline (0.29 ± 0.13 vs. 0.51 ± 0.11). Meanwhile, the fraction shortening, ejection fraction, and longitudinal strain revealed no change between groups. Total and mid-IVPG were significantly correlated with Emax (R = 0.49; p < 0.05, both) but only mid-IVPG was a predictor for Emax (R² = 0.238, p = 0.040). In conclusion, this study revealed that impairment of contractility was the initial changes observed with DXR-ICM in dogs and only IVPG could noninvasively detect subclinical alterations in cardiac function. Color M-mode echocardiography-derived IVPG could be a potential marker for the early detection of doxorubicin cardiomyopathy.

Pulmonic stenosis (PS) is the most common congenital heart disease in dogs and is commonly seen in small breeds, such as Chihuahuas. Conventional treatments have limitations specific to small dogs, including the invasive nature of open-heart surgery and size limitations in percutaneous balloon valvuloplasty. Here, transoesophageal echocardiography (TEE)-guided balloon valvuloplasty via thoracotomy was performed for three small dogs with PS. The procedure was feasible in all cases, including those for which percutaneous treatment was not an option. Although the procedure is invasive, because of the need for thoracotomy, it is one of the treatment options that may be effective for PS, especially in small dogs, as it allows visualisation of the pulmonary artery lesion without relying on the experience of the surgeon.

Objective: This study aimed to investigate the effects of IV ephedrine on heart rate (HR) and mean arterial pressure (MAP) in anesthetized hypotensive dogs and cats and whether the presence or absence of preemptive atropine could influence these effects. Methods: This single-center retrospective study collected the data of dogs and cats that received an initial single IV bolus of ephedrine during anesthesia. The cases were analyzed based on the species, presence or absence of preanesthetic atropine administration, and dose of ephedrine. Mean arterial pressure and HR before and after ephedrine administration; response rate to ephedrine (RRE), defined as the probability of MAP > 70 mm Hg after IV ephedrine administration, with/without atropine; and factors contributing to RRE were analyzed. Results: A total of 1,679 dogs and cats were analyzed. In dogs, IV ephedrine decreased the HR, but preanesthetic atropine prevented this decrease and increased the RRE. In cats, IV ephedrine did not decrease the HR and the RRE did not change significantly, regardless of preanesthetic atropine administration. Multivariate logistic regression analysis revealed that the significant factors contributing to RRE were MAP before ephedrine administration and atropine premedication in dogs and MAP before ephedrine administration in cats. Conclusions: In anesthetized dogs, preemptive atropine enhanced the blood pressure–increasing effect of ephedrine by preventing decreases in HR. In anesthetized cats, IV ephedrine with/without atropine increased MAP without decrease in HR. Clinical Relevance: When IV ephedrine is used for treating hypotension during anesthesia, preemptive atropine is recommended in dogs but has less clinical significance in cats.