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  • Author or Editor: Alan W Spier x
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Abstract

Objective—To evaluate the potential importance of dystrophin, α-sarcoglycan (adhalin), and β-dystroglycan, by use of western blot analysis, in several breeds of dogs with dilated cardiomyopathy.

Sample Population—Myocardial samples obtained from 12 dogs were evaluated, including tissues from 7 dogs affected with dilated cardiomyopathy, 4 control dogs with no identifiable heart disease (positive control), and 1 dog affected with Duchenne muscular dystrophy (negative control for dystrophin). Of the affected dogs, 4 breeds were represented (Doberman Pinscher, Dalmatian, Bullmastiff, and Irish Wolfhound).

Procedure—Western blot analysis was used for evaluation of myocardial samples obtained from dogs with and without dilated cardiomyopathy for the presence of dystrophin and 2 of its associated glycoproteins, α-sarcoglycan and β-dystroglycan.

Results—Detectable differences were not identified between dogs with and without myocardial disease in any of the proteins evaluated.

Conclusions and Clinical Relevance—Abnormalities in dystrophin, α-sarcoglycan, and β-dystroglycan proteins were not associated with the development of dilated cardiomyopathy in the dogs evaluated in this study. In humans, the development of molecular biological techniques has allowed for the identification of specific causes of dilated cardiomyopathy that were once considered to be idiopathic. The use of similar techniques in veterinary medicine may aid in the identification of the cause of idiopathic dilated cardiomyopathy in dogs, and may offer new avenues for therapeutic intervention. ( Am J Vet Res 2001;62:67–71)

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in American Journal of Veterinary Research

Abstract

Objective—To determine aortic ejection velocity in healthy adult Boxers with soft ejection murmurs without overt structural evidence of left ventricular outflow tract obstruction and in healthy Boxers without cardiac murmurs.

Design—Retrospective study.

Animals—201 Boxers.

Procedure—Dogs were examined independently by 2 individuals for evidence of a cardiac murmur, and a murmur grade was assigned. Maximal instantaneous (peak) aortic ejection velocity was measured by means of continuous-wave Doppler echocardiography from a subcostal location. Forty-eight dogs were reexamined approximately 1 year later.

Results—A soft (grade 1, 2, or 3) left-basilar ejection murmur was detected in 113 (56%) dogs. Overall median aortic ejection velocity was 1.91 m/s (range, 1.31 to 4.02 m/s). Dogs with murmurs had significantly higher aortic ejection velocities than did those without murmurs (median, 2.11 and 1.72 m/s, respectively). Auscultation of a murmur was 87% sensitive and 66% specific for the identification of aortic ejection velocity > 2.0 m/s. An ejection murmur and aortic ejection velocity > 2.0 m/s were identified in 73 (36%) dogs. For most dogs, observed changes in murmur grade and aortic ejection velocity during a follow-up examination 1 year later were not clinically important.

Conclusions and Clinical Relevance—Results suggested that ejection murmurs were common among healthy adult Boxers and that Boxers with murmurs were likely to have high (> 2.0 m/s) aortic ejection velocities. The cause of the murmurs in these dogs is unknown. (J Am Vet Med Assoc 2003;222:770–774)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify clinical, echocardiographic, and electrocardiographic abnormalities in Boxers with cardiomyopathy and echocardiographic evidence of left ventricular systolic dysfunction.

Design—Retrospective study.

Animals—48 mature Boxers.

Procedure—Medical records were reviewed for information on age; sex; physical examination findings; and results of electrocardiography, 24-hour ambulatory electrocardiography, thoracic radiography, and echocardiography.

Results—Mean age of the dogs was 6 years (range, 1 to 11 years). Twenty (42%) dogs had a systolic murmur, and 9 (19%) had ascites. Congestive heart failure was diagnosed in 24 (50%) dogs. Seventeen (35%) dogs had a history of syncope. Mean fractional shortening was 14.4% (range, 1% to 23%). Mean left ventricular systolic and diastolic diameters were 4.5 cm (range, 3 to 6.3 cm) and 5.3 cm (range, 3.9 to 7.4 cm), respectively. Twenty-eight (58%) dogs had a sinus rhythm with ventricular premature complexes (VPCs), and 20 had supraventricular arrhythmias (15 with atrial fibrillation and 5 with sinus rhythm and atrial premature complexes). Sixteen of the dogs with supraventricular arrhythmias also had occasional VPCs. Morphology of the VPCs seen on lead II ECGs was consistent with left bundle branch block in 25 dogs, right bundle branch block in 8, and both in 11.

Conclusions and Clinical Relevance—Results suggest that Boxers with cardiomyopathy and left ventricular dysfunction frequently have arrhythmias of supraventricular or ventricular origin. Whether ventricular dysfunction was preceded by electrical disturbances could not be determined from these data, and the natural history of myocardial disease in Boxers requires further study. (J Am Vet Med Assoc 2005;226:1102–1104)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate the effect of 4 antiarrhythmic treatment protocols on number of ventricular premature complexes (VPC), severity of arrhythmia, heart rate (HR), and number of syncopal episodes in Boxers with ventricular tachyarrhythmias.

Design—Randomized controlled clinical trial.

Animals—49 Boxers.

Procedure—Dogs with > 500 VPC/24 h via 24-hour ambulatory ECG (AECG) were treated with atenolol (n = 11), procainamide (11), sotalol (16), or mexiletine and atenolol (11) for 21 to 28 days. Results of pre- and posttreatment AECG were compared with regard to number of VPC/24 h; maximum, mean, and minimum HR; severity of arrhythmia; and occurrence of syncope.

Results—Significant differences between pre- and posttreatment number of VPC, severity of arrhythmia, HR variables, or occurrence of syncope were not observed in dogs treated with atenolol or procainamide. Significant reductions in number of VPC, severity of arrythmia, and maximum and mean HR were observed in dogs treated with mexiletineatenolol or sotalol; occurrence of syncope was not significantly different between these 2 treatment groups.

Conclusions and Clinical Relevance—Treatment with sotalol or mexiletine-atenolol was well tolerated and efficacious. Treatment with procainamide or atenolol was not effective. (J Am Vet Med Assoc 2002;221:522–527)

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in Journal of the American Veterinary Medical Association