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Authors = Hidekazu Koyama

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9 pages, 2237 KiB  
Case Report
A Case of a Small-Breed Dog with Diet-Related Dilated Cardiomyopathy Showing Marked Improvements in Cardiac Morphology and Function after Dietary Modification
by Takahiro Saito, Ryohei Suzuki, Yunosuke Yuchi, Yuyo Yasumura, Takahiro Teshima, Hirotaka Matsumoto and Hidekazu Koyama
Vet. Sci. 2022, 9(11), 593; https://doi.org/10.3390/vetsci9110593 - 27 Oct 2022
Cited by 1 | Viewed by 8851
Abstract
An 11-year-old intact female Papillion weighing 2.1 kg was referred to our institution with the main complaint of shallow, rapid breathing. At the first visit (day 0), although clinical signs improved due to the use of medication from the primary hospital, transthoracic radiography [...] Read more.
An 11-year-old intact female Papillion weighing 2.1 kg was referred to our institution with the main complaint of shallow, rapid breathing. At the first visit (day 0), although clinical signs improved due to the use of medication from the primary hospital, transthoracic radiography and echocardiography revealed left heart enlargement and left ventricular dysfunction. A clinical diagnosis of dilated cardiomyopathy (DCM) was made and oral administration of pimobendan, temocapril, and taurine was initiated. However, on day 10, the respiratory status worsened and furosemide was prescribed. On day 54, no significant improvement in heart size was observed. Additionally, the diet that this patient received met the recommendation for diet-related DCM by the U.S. Food and Drug Administration, and the patient’s diet was changed from a grain-free diet to a grain-containing diet. On day 1191, the patient’s respiratory status was stable and no clinical signs were observed. Transthoracic radiography and echocardiography revealed an improvement in left heart size. Additionally, improvements in the left and right ventricular myocardial strains were observed after changing the diet. We suggest that it may be necessary to suspect a dietary association with dilated cardiomyopathy, and a good prognosis might be expected by dietary modification, even in small-breed dogs. Full article
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12 pages, 764 KiB  
Article
Beraprost Sodium for Pulmonary Hypertension in Dogs: Effect on Hemodynamics and Cardiac Function
by Ryohei Suzuki, Yunosuke Yuchi, Takahiro Saito, Yuyo Yasumura, Takahiro Teshima, Hirotaka Matsumoto and Hidekazu Koyama
Animals 2022, 12(16), 2078; https://doi.org/10.3390/ani12162078 - 15 Aug 2022
Cited by 8 | Viewed by 3495
Abstract
Pulmonary hypertension (PH) is a fatal condition that affects many dogs. In humans, PH is often treated with beraprost sodium (BPS). However, the effectiveness of BPS for canine PH has not been established. This study aimed to evaluate the clinical and cardiovascular response [...] Read more.
Pulmonary hypertension (PH) is a fatal condition that affects many dogs. In humans, PH is often treated with beraprost sodium (BPS). However, the effectiveness of BPS for canine PH has not been established. This study aimed to evaluate the clinical and cardiovascular response of BPS in canine patients with PH of various causes. Sixteen dogs with PH (post-capillary PH, n = 8; pre-capillary PH, n = 8) were included. BPS was continuously administered twice daily at 15 µg/kg. All dogs underwent echocardiography, including speckle-tracking analysis and blood pressure measurement, before and after BPS administration. Continuous BPS administration (range: 13.2–22.0 µg/kg) significantly decreased the pulmonary and systemic vascular impedance and increased left and right ventricular myocardial strain. In dogs with post-capillary PH, BPS administration caused no significant worsening of the left atrial pressure indicators. No side effects of BPS were observed in any dog. BPS also improved cardiac function and pulmonary circulation through pulmonary vasodilation, suggesting that BPS may be an additional treatment option for canine PH of various causes. Particularly, BPS increased left ventricular function and systemic circulation without worsening the left heart loading condition in dogs with post-capillary PH. Full article
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15 pages, 1907 KiB  
Article
Utility of Real-Time Three-Dimensional Echocardiography for the Assessment of Right Ventricular Morphology and Function in Large Animal Models
by Yunosuke Yuchi, Ryohei Suzuki, Riho Higuchi, Takahiro Saito, Takahiro Teshima, Hirotaka Matsumoto and Hidekazu Koyama
J. Clin. Med. 2022, 11(7), 2001; https://doi.org/10.3390/jcm11072001 - 2 Apr 2022
Cited by 4 | Viewed by 2519
Abstract
Real-time three-dimensional echocardiography (RT3DE) enables a noninvasive assessment of right ventricular (RV) morphology. However, no study has evaluated the relationship between RV function obtained by RT3DE and RV pressure-volume loops. This hypothesis-driven, experimental study aimed to assess the utility of RT3DE in the [...] Read more.
Real-time three-dimensional echocardiography (RT3DE) enables a noninvasive assessment of right ventricular (RV) morphology. However, no study has evaluated the relationship between RV function obtained by RT3DE and RV pressure-volume loops. This hypothesis-driven, experimental study aimed to assess the utility of RT3DE in the evaluation of RV morphology and function. Ten anesthetized beagle dogs sequentially underwent dobutamine infusion, acute infusion of lactated Ringer’s solution, and furosemide administration to alter RV contractility and loading conditions. RV pressure-volume loop-derived hemodynamic measurements and echocardiography, including two-dimensional speckle-tracking echocardiography and RT3DE, were performed in each study protocol. Bland–Altman analysis showed strong agreement in RV volume, ejection fraction, and stroke volume obtained by right heart catheterization and RT3DE. Multiple regression analyses revealed that the peak myocardial velocity of the lateral tricuspid annulus (RV s’) and global RV longitudinal strain rate were significantly associated with end-systolic elastance (adjusted r2 = 0.66, p < 0.001). RV s’, RV free wall longitudinal strain, and RT3DE-derived stroke volume/end-systolic RV volume ratio were associated with RV pressure-volume loops-derived end-systolic/arterial elastance ratio (adjusted r2 = 0.34, p < 0.001). RT3DE could detect the changes in catheterization-derived RV volume with a strong agreement and might be useful in estimating RV-pulmonary arterial coupling. Full article
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13 pages, 2094 KiB  
Article
Left and Right Myocardial Functionality Assessed by Two-Dimensional Speckle-Tracking Echocardiography in Cats with Restrictive Cardiomyopathy
by Ryohei Suzuki, Yunosuke Yuchi, Haruka Kanno, Takahiro Teshima, Hirotaka Matsumoto and Hidekazu Koyama
Animals 2021, 11(6), 1578; https://doi.org/10.3390/ani11061578 - 28 May 2021
Cited by 10 | Viewed by 5312
Abstract
The endomyocardial form of restrictive cardiomyopathy (EMF-RCM), a primary disorder of the myocardium, is one of the diseases with poor prognosis in cats. We hypothesized that both the left and right myocardial functional abnormalities may occur in cats with EMF-RCM, causing this disease [...] Read more.
The endomyocardial form of restrictive cardiomyopathy (EMF-RCM), a primary disorder of the myocardium, is one of the diseases with poor prognosis in cats. We hypothesized that both the left and right myocardial functional abnormalities may occur in cats with EMF-RCM, causing this disease pathophysiology and clinical status. Out of the 25 animals included in this study, 10 were client-owned cats with EMF-RCM, and 15 were healthy cats. In this study, cats were assessed for layer-specific myocardial function (whole, endocardial, and epicardial) in the left ventricular longitudinal and circumferential directions, and right ventricular longitudinal direction, via two-dimensional speckle-tracking echocardiography (2D-STE). Cats with EMF-RCM had depressed left ventricular myocardial deformations both in systole (whole longitudinal strain, epicardial longitudinal strain, and endocardial circumferential strain) and diastole (early and late diastolic longitudinal strain rates, and late diastolic circumferential strain rate) compared to controls. Furthermore, some right ventricular myocardial deformations (systolic longitudinal strain in epicardial layers, and endocardial-to-epicardial strain ratio) were significantly differerent in cats with EMF-RCM. Myocardial function assessed by 2D-STE could reveal left and right myocardial dysfunction. Full article
(This article belongs to the Special Issue Early Detection of Heart Failure in Animals)
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