Decreased sympathetic tone after short-term treatment with enalapril in dogs with mild chronic mitral valve disease

Heart rate variability (HRV) and echocardiography were performed in 14 dogs with mitral regurgitation (MR) before and after 14 days of 0.5 mg/kg/day of enalapril treatment. All dogs were in heart failure stages B1 and B2. After enalapril treatment, left ventricular end diastolic diameter (LVEDd), left ventricular end diastolic diameter normalized for body weight (LVEDdN) and percent mitral regurgitant jet decreased (P < 0.05). The diastolic blood pressure decreased (P < 0.05). Increased time domain parameters of HRV were found. For frequency domain analysis, the total frequency (TF) increased significantly (P < 0.05). The normalized low frequency (LF norm) decreased while normalized high frequency (HF norm) increased causing significant reduction in LF/HF (P < 0.05). Before enalapril treatment, LF was correlated with end diastolic volume (EDV) (P < 0.01) and LVEDd (P < 0.05). In conclusion, MR dogs receiving enalapril treatment for 14 days had increased cardiac parasympathetic tone while sympathetic tone was suppressed. The decreased sympathetic activity corresponded to the reduction in cardiac preload and afterload.     

有机、无机添加剂改良反酸田水稻生长效果研究

采用盆栽试验研究不同有机、无机添加剂对反酸田水稻生长的影响。结果表明:钙镁磷肥+NK处理、石灰+NPK处理、自研改良剂+NPK处理的水稻产量极显著高于其它改良处理,且较NPK处理的产量分别提高了32.2倍、22.2倍、19.5倍;株高、最长根长、根系干重及植株干重均显著高于其它各处理,与NPK处理比较,株高分别增加60.4%、62.5%、56.3%,根系干重分别增加891.7%、626.4%、502.8%,植株干重分别增加1 148.0%、699.3%、573.6%。有机、无机添加剂能在一定程度上改善水稻土壤pH值,尤其是添加石灰、自研改良剂和钙镁磷肥处理的pH值均高于4.5,显著高于其他各处理。综上可知,钙镁磷肥、石灰与自研改良剂均能有效提高土壤pH值,显著改善水稻生长并提高稻谷产量,是改良反酸田行之有效的添加物。而腐植酸、精制有机肥、碱性有机肥、碱渣、粉煤灰及磷矿粉能在一定程度上改善水稻生物学特性,但并未显著降低土壤酸度。     

Trifoliate left atrioventricular valve with and without intact septal structures in four dogs: echocardiographic findings and surgical repair

Trifoliate left atrioventricular (AV) valve with common atrioventricular junction is considered part of the spectrum of atrioventricular septal defect. This valve morphology is typically associated with defects in the AV septum resulting in communication at the atrial or ventricular level, but has also been described as an isolated defect in the setting of a common AV junction without AV septal defect. Trifoliate left AV valve exhibits a line of apposition between the bridging leaflets that is directed toward the inlet interventricular septum, distinguishing it from isolated mitral valve cleft in which the orientation of the bridging leaflets are toward the left ventricular outflow tract. The echocardiographic findings of four dogs with trifoliate left AV valve are described; two with intact septal structures and two with large ostium primum defects. Three dogs underwent open surgical repair using different approaches depending on the presence or absence of a septal defect. One of these underwent concurrent surgical repair for right AV valve dysplasia. One dog with intact septal structures underwent interventional closure of a concurrent patent ductus arteriosus. Current terminology associated with trileaflet left AV valve malformations is reviewed.     

Videofluoroscopy,CT angiography,and ultrasonography of congenital esophageal stenosis in a Labrador retriever

A 7‐week‐old Labrador retriever presented for further investigation into acute onset regurgitation, following weaning from liquid to solid food. A videofluoroscopic swallow study demonstrated a severe, focal esophageal dilation in the mid‐cervical region, with marked luminal narrowing distally. Computed tomography with angiography revealed esophageal stenosis, extending from C4–T2, secondary to circumferential esophageal wall thickening. With the concern for development of secondary aspiration pneumonia, the owners elected to euthanize the dog and consented to postmortem examination. A diagnosis of segmental, cervical esophageal muscular hypertrophy was made on necropsy, consistent with the fibromuscular thickening type of congenital esophageal stenosis reported in humans.     

Noninvasive Clinical Assessment of Systolic Torsional Motions by Two‐Dimensional Speckle‐Tracking Echocardiography in Dogs with Myxomatous Mitral Valve Disease

Background

Left ventricular torsional motion plays an important role for effective pump function. However, noninvasive clinical assessment of torsional deformations by two‐dimensional speckle‐tracking echocardiography (2D‐STE) in dogs with myxomatous mitral valve disease (MMVD) has not been reported.

Hypothesis

Left ventricular torsion is determined by the native orientation of the helical myocardial fibers, such that it might provide better assessment of myocardial function than conventional methods.

Animals

Sixty‐seven client‐owned dogs with MMVD were classified into 3 classes based on the International Small Animal Cardiac Health Council classification and 16 weight‐ and age‐matched healthy dogs.

Methods

Dogs were examined for myocardial deformations by 2D‐STE and were evaluated for peak systolic rotation and rotation rate at each basal and apical view. Dogs also were evaluated for peak systolic torsion and torsion rate.

Results

Peak systolic torsion was higher in class II than in class I (P < .001) dogs. Peak systolic torsion was lower in class III than in class II (P = .001) dogs and controls (P = .003).

Conclusions and Clinical Importance

Torsional deformations assessed by 2D‐STE differed among clinical classes of MMVD. Myocardial torsional deformations by 2D‐STE may provide more detailed assessment of contractile function in dogs with MMVD.     

Gingival Hyperplasia Associated with the Administration of Amlodipine to Dogs with Degenerative Valvular Disease (2004–2008)

Background: Calcium channel blocking drugs, usually nifedipine and less often amlodipine, have been reported to cause gingival hyperplasia (GH) in humans.
Hypothesis: Amlodipine, a dihydropyridine calcium channel blocking drug, can cause GH when administered chronically to older small dogs with degenerative valvular disease.
Animals Studied: From January 2004 to May 2008, 82 client-owned dogs with degenerative valvular disease and left atrial dilatation were treated with amlodipine in combination with spironolactone and enalapril and followed for >6 months.
Methods: Retrospective study. A chronological observation of GH in 2 dogs treated with amlodipine in 2004 and 2006 prompted the study. Patient histories and medical records of each dog treated with amlodipine for degenerative valvular disease from January 2004 to May 2008 were reviewed.
Results: GH was observed by clients and the authors in 7 of 82 (8.5%) dogs. Histologic confirmation of the diagnosis was made in 2 dogs. The minimum duration of treatment before diagnosis of GH was 5 months. GH began to resolve within 2 weeks of discontinuing amlodipine and resolution was complete within 6 months. Amlodipine administration was reinstituted in 1 dog in which GH had resolved, and GH reoccurred within 4 months.
Conclusion and Clinical Importance: Long-term administration of amlodipine to dogs with degenerative valvular disease may cause GH in a small percentage of patients. GH resolves quickly after withdrawal of amlodipine treatment.