• Journal of Veterinary Clinics
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• v.39 no.6
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• pp.287-293
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• 2022

Radiographic left atrial dimension (RLAD) is a useful measurement to assess left atrial enlargement in dogs. There are studies on the use of RLAD on various breeds of dogs, but no study on a specific breed with myxomatous mitral valve disease (MMVD). This study was conducted to compare RLAD measurements in Maltese dogs with MMVD ACVIM stage B1 and B2, and also to investigate the correlation of RLAD with the LA:Ao ratio. A total of 29 Maltese dogs were the subjects of this study. Each dog was diagnosed with MMVD ACVIM stage B1 or B2 based on physical examination, thoracic radiography, and echocardiography. The vertebral heart size (VHS), RLAD, LVIDDn, and LA:Ao ratio were measured and compared to evaluate the differences. There were significant differences in the RLAD, LVIDDn, and LA:Ao ratio between dogs with MMVD ACVIM stage B1 and those with stage B2. There was a significant correlation between the LA:Ao ratio and both the RLAD and VHS measurements, but the correlation coefficient was higher for RLAD. The RLAD scores exhibited a significant difference between dogs with ACVIM Stage B1 and with those with B2, and these scores had a higher correlation with the LA:Ao ratio measured by echocardiography than with VHS.

• Journal of Chest Surgery
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• v.13 no.4
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• pp.338-345
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• 1980

We have modified an isolated perfusion rat heart model of cardiopulmonary bypass, with which we are able to screen the effects of various cardioplegic solutions and hypothermia upon the ability of the heart to survivie during and recover from period of ischemic arrest. The modified experimental model was differed from the original as follow : a heat coil chamber of atrial and aortic reservoir provided temperature control, and the perfusate was gassed with each pure oxygen and pure carbon dioxide in 95:5 ratio. The Langendorff perfusion was initiated for a 10 minute period by introducing perfusate at $37^{\circ}C.$ into the aorta from the aortic reservoir located 100 cm above the heart. The isolated perfused working rat heart model was a left heart preparation in which oxygenated perfusion medium (at $37^{\circ}C.$) entered the cannulated left atrium at a pressure of 20 cm $H_{2}O$ and was passed to the ventricle, from which it was sponeously elected(no electrical pacing) via an aortic cannula, against a hydrostatic pressure of 100cm $H_{2}O$. during this working period various indices of cardiac functin were measured. The cardiac functions were stable for over 3 hour with perfusion of Krebs-Henseleit bicarbonate buffer solution containing only glucose (11.1 mM/L). The percentage of cardiac functins were maintained about 94% on heart rate, 80.6% on peak aortic pressure, 87.7% on coronary flow and 76.3% on aortic flow rate after 3 hour of working heart perfusion at a pressure of 20 cm $H_{2}O$. We believe this preparation to be a good biochemical model for the human heart which offers many advantages including economic, speed of preparation, reproducibility, and the ability to handle large numbers.

• Journal of Veterinary Clinics
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• v.32 no.1
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• pp.5-8
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• 2015

D-dimer is a fibrin degradation product (FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. D-dimer concentration is widely used for determining thrombosis and thromboembolism. Because one major cause of thromboembolism is congestive heart failure in human, we investigated the degree and risk of thromboembolism in dogs with different stage of congestive heart failure caused by chronic mitral valvular insufficiency (CMVI). The plasma level of d-dimer was evaluated in 20 healthy dogs and 30 dogs with different stage of congestive heart failure caused by CMVI. The d-dimer concentrations were measured by a commercialized assay kit. The plasma levels of d-dimer were not significantly different between healthy and CMVI dogs. Furthermore, there was no association of d-dimer concentrations to left atrium to aorta (LA/Ao) ratio, left ventricular dimension at diastole to aorta (LVIDd/Ao) ratio and severity of heart failure in our study population. Our study results implied that the degree of thromboembolism in canine heart failure might be minimal or the plasma d-dimer test might not be reliable for detecting thromboembolism in dogs.

• Journal of Chest Surgery
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• v.35 no.7
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• pp.511-516
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• 2002

Background: This study was undertaken in infant patients with isolated ventricular septal defect(VSD) to determine the effect of surgical closure on ventricular systolic time interval, as a parameter for ventricular performance, by echocardiography. Material and Method: Thirty patients were enrolled. Mean age of patients at operation was 6.5$\pm$3.2 months and all patients had non-restrictive VSD. We checked the left atrium/aorta(LA/Ao) ratio, left ventricle ejection fraction(EF), left ventricular systolic time interval(LVSTI), and right ventricular systolic time interval(RVSTI). Echocardiographic studies were done before surgical correction and postoperative periods(postopl: within 2 weeks, postop2: between 4 and 6 months, postop3: between 1 and 2 years). Result: LA/Ao ratio decreased significantly at immediate postoperative period compared to preoperative period and sustained during further follow-up period(from 1.74$\pm$0.37 to 1.36$\pm$0.24＊, 1.32$\pm$0.22＊, and 1.27$\pm$0.19＊, p<0.01). LV EF had not changed during follow-up periods(from 65.1$\pm$7.0 to 62.3$\pm$9.5, 62.8$\pm$5.7, and 64.1$\pm$6.9). LVSTI decreased significantly at postop2 and sustained during further follow-up period (from 0.46$\pm$0.13 to 0.46$\pm$0.11, 0.37$\pm$0.08＊, and 0.34$\pm$0.07＊, p<0.01). RVSTI decreased significantly at postop3(0.33$\pm$0.08 to 0.32$\pm$0.08, 0.31$\pm$0.07, and 0.27$\pm$0.05＊, p<0.01). Conclusion: We found that right and left ventricular systolic time intervals had decreased over the period of 1 year after surgical correction of VSD. Therefore, it is necessary to observe the change of ventricular function during that period.