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A14-year-old 3.5-kg (7.7-lb) castrated male domestic shorthair cat was evaluated by the Neurology Service at the University of Florida Veterinary Medical Center because of a 2-month history of profound weakness, ataxia, head tremors, and suspected seizures. Approximately 1 year previously, a diagnosis of inflammatory bowel disease had been made at another veterinary hospital, which was controlled via administration of prednisolone (1.4 mg/kg [0.64 mg/lb], PO, q 12 h). One week before referral to the Veterinary Medical Center, a CBC revealed normochromic, normocytic, nonregenerative anemia (Hct, 27.9%; reference range, 30% to 48%) and a stress leukogram (WBC count, 29.2 × 10

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in Journal of the American Veterinary Medical Association

A2-year-old 41.0-kg (90.2-lb) neutered male Bernese Mountain Dog (dog 1) was evaluated at the Veterinary Medical Center, University of Florida because of 2 episodes of syncope within a 2-day period. The dog had no previous history of weakness or lethargy, but was inactive because it had undergone a tibial plateau leveling osteotomy 10 days earlier. It also had a history of hypothyroidism, recurrent pyoderma, and chronic weight loss. The dog was receiving treatment with tramadol (1.2 mg/kg [0.55 mg/lb], PO, q 12 h) and thyroxine (0.007 mg/kg [0.003 mg/lb], PO, q 12 h).

At the initial evaluation, the dog was

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in Journal of the American Veterinary Medical Association

A 4-year-old 1.4-kg (3.1-lb) male Chihuahua was referred for sudden onset of ataxia and stupor. Physical examination revealed a rectal temperature of 37°C (98.6°F) and a respiratory rate of 32 breaths/min. The dog's heart rate was 60 beats/min, and auscultation revealed a pronounced regularly irregular rhythm, no murmurs, and crackles bilaterally in the dorsal aspects of the lung fields. Tetraparesis was evident, and reflexes in all limbs were diminished; ataxia was detectable during ambulation. Cranial nerve function was intact but a delayed menace response was detected in each eye. Abnormal findings of a CBC included leukocytosis, neutrophilia, a left shift,

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare procedure times and major and minor complication rates associated with single-chamber versus dual-chamber pacemaker implantation and with 1-lead, 2-lead, and 3-lead pacemaker implantation in dogs with clinical signs of bradyarrhythmia.

Design—Retrospective case series.

Animals—54 dogs that underwent pacemaker implantation because of clinical signs of bradyarrhythmia.

Procedures—Medical records of dogs that received pacemakers between July 2004 and December 2009 were reviewed for information regarding signalment, diagnosis, pacemaker implantation, pacemaker type, complications, and survival time. Analyses were performed to determine significant differences in anesthesia time, procedure time, and outcome for dogs on the basis of pacing mode and number of pacing leads.

Results—28 of 54 (51.9%) dogs received single-chamber pacemakers and 26 (48.1%) received dual-chamber pacemakers. Mean ± SD procedural time was significantly longer for patients with dual-chamber pacemakers (133.5 ± 51.3 minutes) than for patients with single-chamber pacemakers (94.9 ± 37.0 minutes), and procedure time increased significantly as the number of leads increased (1 lead, 102.3 ± 51.1 minutes; 2 leads, 114.9 ± 24.8 minutes; 3 leads, 158.2 ± 8.5 minutes). Rates of major and minor complications were not significantly different between dogs that received single-chamber pacemakers and those that received dual-chamber pacemakers or among dogs grouped on the basis of the number of pacing leads placed.

Conclusions and Clinical Relevance—Although dual-chamber pacemaker implantation did result in increased procedural and anesthesia times, compared with single-chamber pacemaker implantation, this did not result in a higher complication rate.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyi).

Animals—20 healthy zebras.

Procedures—Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras.

Results—Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean ± SD heart rate of 67 ± 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra.

Conclusions and Clinical Relevance—Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras.

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in American Journal of Veterinary Research

Abstract

Objective—To compare the acute effects of cardiac pacing from various transvenous pacing sites on left ventricular (LV) function and synchrony in clinically normal dogs.

Animals—10 healthy adult mixed-breed dogs.

Procedures—Dogs were anesthetized, and dual-chamber transvenous biventricular pacing systems were implanted. Dogs were paced in single-chamber mode from the right atrial appendage (RAA) alone and in dual-chamber mode from the right ventricular apex (RVA), from the left ventricular free wall (LVFW), and simultaneously from the RVA and LVFW (BiV). Standard ECG and echocardiographic measurements, cardiac output measured with the lithium dilution method (LiDCO), and tissue Doppler–derived measurements of LV synchrony were obtained during each of the pacing configurations.

Results—Placement of the biventricular pacing systems was possible in 8 of the 10 dogs. The QRS duration was significantly different among all pacing sites, and the order of increasing duration was RAA, BiV, LVFW, and RVA. Pacing sites did not differ with respect to fractional shortening; however, pacing from the RVA resulted in a significantly lower ejection fraction than pacing from all other sites. During RVA and LVFW pacing, LiDCO was significantly lower than that at other sites; there was no significant difference between RAA and BiV pacing with respect to LiDCO. Although the degree of dyssynchrony was significantly lower during pacing from the RAA versus other ventricular pacing sites, it was not significantly different among sites.

Conclusions and Clinical Relevance—Ventricular activation by RAA pacing provided the best LV function and synchrony. Pacing from the RVA worsened LV function, and although pacing from the LVFW improved it, BiV pacing may provide additional improvement.

Full access
in American Journal of Veterinary Research