Clinical progression of X-linked muscular dystrophy in two German Shorthaired Pointers.

CASE DESCRIPTION: 2 full-sibling male German Shorthaired Pointer (GSHP) puppies (dogs 1 and 2) with X-linked muscular dystrophy and deletion of the dystrophin gene (gene symbol, DMD) each had poor growth, skeletal muscle atrophy, pelvic limb weakness, episodic collapse, and episodes of coughing. CLINICAL FINDINGS: Initial examination revealed stunted growth, brachygnathism, trismus, and diffuse neuromuscular signs in each puppy; clinical signs were more severe in dog 2 than in dog 1. Immunohistochemical analysis revealed a lack of dystrophin protein in both dogs. During the next 3 years, each dog developed hyperinflation of the lungs, hypertrophy of the cervical musculature, and hypertrophy of the lateral head of the triceps brachii muscle. TREATMENT AND OUTCOME: Monitoring and supportive care were provided at follow-up visits during an approximately 7-year period. No other specific treatment was provided. Neuromuscular signs in both dogs remained stable after 3 years of age, with dog 2 consistently more severely affected than dog 1. The dogs had multiple episodes of aspiration pneumonia; dogs 1 and 2 were euthanatized at 84 and 93 months of age, respectively. CLINICAL RELEVANCE: The clinical course of disease in these dogs was monitored for a longer period than has been monitored in previous reports of dystrophin-deficient dogs. The clinical progression of muscular dystrophy in the 2 GSHPs was compared with that for other breeds and species with dystrophin-deficient conditions, and the potential basis for the phenotypic variation observed between these littermates, along with potential therapeutic ramifications for dogs and humans, was evaluated.

Results of the veterinary enalapril trial to prove reduction in onset of heart failure in dogs chronically treated with enalapril alone for compensated, naturally occurring mitral valve insufficiency.

OBJECTIVE: To determine the efficacy of long-term enalapril administration in delaying the onset of congestive heart failure (CHF). DESIGN: Placebo-controlled, double-blind, multicenter, randomized trial. ANIMALS: 124 dogs with compensated mitral valve regurgitation (MR). PROCEDURES: Dogs randomly assigned to receive enalapril or placebo were monitored for the primary endpoint of onset of CHF for < or = 58 months. Secondary endpoints included time from study entry to the combined endpoint of CHF-all-cause death; number of dogs free of CHF at 500, 1,000, and 1,500 days; and mean number of CHF-free days. RESULTS: Kaplan-Meier estimates of the effect of enalapril on the primary endpoint did not reveal a significant treatment benefit. Chronic enalapril administration did have a significant benefit on the combined endpoint of CHF-all-cause death (benefit was 317 days [10.6 months]). Dogs receiving enalapril remained free of CHF for a significantly longer time than those receiving placebo and were significantly more likely to be free of CHF at day 500 and at study end. CONCLUSIONS AND CLINICAL RELEVANCE: Chronic enalapril treatment of dogs with naturally occurring, moderate to severe MR significantly delayed onset of CHF, compared with placebo, on the basis of number of CHF-free days, number of dogs free of CHF at days 500 and study end, and increased time to a combined secondary endpoint of CHF-all-cause death. Improvement in the primary endpoint, CHF-free survival, was not significant. Results suggest that enalapril modestly delays the onset of CHF in dogs with moderate to severe MR.

Noninvasive transthoracic temporary cardiac pacing in dogs.

Temporary cardiac pacing is used in the emergency treatment of life-threatening bradyarrhythmias and for the support of heart rate and blood pressure of patients with sick sinus syndrome or high-grade atrioventricular (AV) block undergoing general anesthesia, typically for permanent pacemaker implantation. We retrospectively evaluated the safety and efficacy of a noninvasive transthoracic external cardiac pacing system in 42 dogs treated for bradyarrhythmias. Optimal placement of the patch electrodes on the skin of the thorax was initially established on 2 anesthetized normal dogs. The optimal electrode placement was determined to be on the right and left hemithoraces, directly over the heart. Afterward, by means of this electrode placement all 42 dogs treated for bradyarrhythmias in this study were successfully paced with the noninvasive transthoracic system. Dogs ranged in age from 1 to 15 years and weighed between 3.2 and 40 kg. Miniature Schnauzers, German Shepherds, and mixed breeds were most common in the study population. Indications for noninvasive transthoracic pacing included emergency treatment of hemodynamically unstable 3rd-degree AV block (2 dogs): support of heart rate during general anesthesia for permanent pacemaker implantation or lead-wire adjustment (38 dogs): and support of heart rate during general anesthesia for ophthalmologic surgery in dogs with sick sinus syndrome (2 dogs). Complications included pain and skeletal muscle stimulation, which required general anesthesia. We conclude that the noninvasive transthoracic pacing system evaluated is satisfactory for clinical veterinary use.

Effects of long-term administration of enalapril on clinical indicators of renal function in dogs with compensated mitral regurgitation.

OBJECTIVE: To determine the effect of long-term administration of enalapril on renal function in dogs with severe, compensated mitral regurgitation. DESIGN: Randomized controlled trial. ANIMALS: 139 dogs with mitral regurgitation but without overt signs of heart failure. PROCEDURE: Dogs were randomly assigned to be treated with enalapril (0.5 mg/kg [0.23 mg/lb], PO, q 24 h) or placebo, and serum creatinine and urea nitrogen concentrations were measured at regular intervals for up to 26 months. RESULTS: Adequate information on renal function was obtained from 132 dogs; follow-up time ranged from 0.5 to 26 months (median, 12 months). Mean serum creatinine and urea nitrogen concentrations were not significantly different between dogs receiving enalapril and dogs receiving the placebo at any time, nor were concentrations significantly different from baseline concentrations. Proportions of dogs that developed azotemia or that had a +/- 35% increase in serum creatinine or urea nitrogen concentration were also not significantly different between groups. CONCLUSIONS: And Clinical Relevance: Results suggest that administration of enalapril for up to 2 years did not have any demonstrable adverse effects on renal function in dogs with severe, compensated mitral regurgitation.