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Abstract

Objective—To determine reference values for M-mode echocardiographic parameters in nonsedated healthy adult Maine Coon cats and compare those values with data reported for nonsedated healthy adult domestic cats.

Design—Prospective study.

Animals—105 healthy adult Maine Coon cats.

Procedure—Over a 3-year period, M-mode echocardiographic examinations (involving a standard right parasternal transthoracic technique) were performed on Maine Coon cats as part of prebreeding evaluations;values of M-mode parameters in healthy individuals were collected, and mean values were calculated for comparison with those reported for healthy adult domestic cats.

Results—The mean ± SD weight of Maine Coon cats was significantly greater than that of domestic cats. Mean values of left ventricular internal dimension at end diastole and end systole (LVIDd and LVIDs, respectively), interventricular septal thickness at end systole (IVSs), left ventricular posterior wall thickness at end systole (LVPWs), left atrial dimension at end systole (LADs), and aortic root dimension (Ao) in Maine Coon cats differed significantly from values in healthy domestic cats. The greatest differences detected between the 2 groups involved values of LVIDd, LADs, and Ao. Linear regression analysis revealed a weak but significant correlation between weight and each of LVIDd, LVPWs, IVSs, Ao, LADs, and left ventricular posterior wall thickness at end diastole.

Conclusions and Clinical Relevance—Values of several M-mode echocardiographic parameters in Maine Coon cats differ from those reported for domestic cats; these differences should be considered during interpretation of echocardiographic findings to distinguish between cardiac health and disease in this breed. (J Am Vet Med Assoc 2005;226:734–737)

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To evaluate a group of related Rhodesian Ridgebacks with a family history of sudden death for the presence of arrhythmia and to identify possible patterns of disease inheritance among these dogs.

DESIGN Prospective case series and pedigree investigation.

ANIMALS 25 Rhodesian Ridgebacks with shared bloodlines.

PROCEDURES Pedigrees of 4 young dogs (1 female and 3 males; age, 7 to 12 months) that died suddenly were evaluated, and owners of closely related dogs were asked to participate in the study. Dogs were evaluated by 24-hour Holter monitoring, standard ECG, echocardiography, or some combination of these to assess cardiac status. Necropsy reports, if available, were reviewed.

RESULTS 31 close relatives of the 4 deceased dogs were identified. Of 21 dogs available for examination, 8 (2 males and 6 females) had ventricular tachyarrhythmias (90 to 8,700 ventricular premature complexes [VPCs]/24 h). No dogs had clinical signs of cardiac disease reported. Echocardiographic or necropsy evaluation for 7 of 12 dogs deemed affected (ie, with frequent or complex VPCs or sudden death) did not identify structural lesions. Five of 6 screened parents of affected dogs had 0 to 5 VPCs/24 h (all singlets), consistent with a normal reading. Pedigree evaluation suggested an autosomal recessive pattern of inheritance, but autosomal dominant inheritance with incomplete penetrance could not be ruled out.

CONCLUSIONS AND CLINICAL RELEVANCE Holter monitoring of Rhodesian Ridgebacks with a family history of an arrhythmia or sudden death is recommended for early diagnosis of disease. An autosomal recessive pattern of inheritance in the studied dogs was likely, and inbreeding should be strongly discouraged.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine whether standard manual frequency filters in the ON and OFF settings affected P-QRS-T voltages, discover whether recorded P-QRS-T voltages vary between commercial electrocardiographs, assess effects of frequency filters on base-line artifact, and evaluate ecg frequency content by high-fidelity recordings subjected to digital filters with variable frequencies.

Design

Sequential 10-lead ecg were recorded in 30 cats, using 3 commercial electrocardiographs to assess effects of manual frequency filters on the P-QRS-T wave forms. Three clinically normal cats were evaluated for ecg frequency content.

Animals

Thirty cats (13 with hypertrophic cardiomyopathy; 4 with restrictive cardiomyopathy; 3 hyperthyroid; 1 with ventricular septal defect; 1 with aortic stenosis; and 8 with no detectible cardiovascular disease). Three additional clinically normal cats were studied for effects of frequency filters on the ecg frequency content.

Procedures

Ten-lead ecg were recorded on each cat by use of 3 commercial electrocardiographs sequentially. For each machine, a recording was made with manual filters ON, immediately followed by a recording with manual filters OFF. High-fidelity lead-II ecg recordings were made with filters set with their rolloff frequency at 0.1 Hz and 3.0 kHz; output voltage (0.2 mV/V) was fed to an analog-to-digital converter, then to attendant software, which sampled the signal at 6 kHz with a 12-bit sampler, and were digitally filtered at various corner frequencies.

Results

Voltages recorded by all 3 electrocardiographs were greatest when filters were OFF (most prominent on R- and S-wave voltages). In all recorded leads, R-wave voltage was significantly greater when filters were OFF than ON. Comparison of voltages indicated significant (P < 0.05) differences between R-wave voltages recorded in all leads with manual filters ON, but not with filters OFF. With filters ON, each electrocardiograph produced a smaller percentage of recordings with moderate to severe baseline artifact than with filters OFF. R-Wave amplitudes of high-fidelity lead-II ecg were significantly decreased with digital filters set at corner frequencies < 150 Hz.

Conclusions

Significant (P < 0.05) voltage attenuation was recorded by each of the 3 commercial electrocardiographs when frequency filters were ON, compared with OFF. Comparison of waveform voltages among electrocardiographs with filters ON indicated significant variation in R-wave amplitudes in all leads. With manual filters ON, each electrocardiograph recorded a smaller percentage of recordings with baseline artifact than with filters OFF. Substantial frequency components ≥ 150 Hz are present in the feline ecg waveform. Thus, filters with frequencies < 150 Hz markedly attenuate the feline R wave.

Clinical Relevance

Attenuation of feline ecg signals occurs with use of commercial electrocardiographs and varies greatly between manufacturers. This is attributable largely to internal manual frequency filters. These consequences may be important when applying standard feline reference values or when equivocal voltage measurements are recorded.

Free access
in American Journal of Veterinary Research

Objective

To describe the historical, clinical, and echocardiographic findings in Dalmatians with dilated cardiomyopathy (DCM).

Design

Retrospective case series.

Sample Population

9 Dalmatians with a diagnosis of DCM and congestive heart failure (CHF), 9 Doberman Pinschers with DCM and CHF, and 9 dogs of other breeds with DCM and CHF.

Procedure

Disease history; signalment; physical, radiographic, and echocardiographic examination findings; treatment; and outcome from medical records were analyzed.

Results

All Dalmatians were male, with a mean age of 6.8 years. Eight dogs had been fed a commercially available low-protein diet formulated for the prevention of urate uroliths. All dogs had clinical signs consistent with left-sided CHF and had marked left ventricular systolic dysfunction and severe left ventricular dilatation, although arrhythmias were not an important finding in this series of dogs. Median duration of survival was 10 months.

Clinical Implications

The DCM syndrome in Dalmatians has some qualities that are distinct from DCM in other breeds of dogs. (J Am Vet Med Assoc 1996;209:1592–1596)

Free access
in Journal of the American Veterinary Medical Association

Abstract

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 ≤ 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.

Full access
in Journal of the American Veterinary Medical Association

Abstract

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. (J Am Vet Med Assoc 2002;221: 654–658)

Full access
in Journal of the American Veterinary Medical Association