Echocardiographic and electrocardiographic findings in Irish Wolfhounds eating high-pulse or low-pulse diets

BACKGROUND

Apparently healthy dogs of various breeds eating nontraditional, high-pulse diets can have larger left ventricular diameter, lower systolic function, and more ventricular premature complexes (VPCs) compared with dogs eating traditional, low-pulse diets. It is unknown whether Irish Wolfhounds eating high-pulse diets have similar cardiac abnormalities.

HYPOTHESIS/OBJECTIVES

To compare electrocardiographic and echocardiographic findings between Irish Wolfhounds eating high- or low-pulse diets.

ANIMALS

Ninety-seven Irish Wolfhounds.

METHODS

Retrospective study of Irish Wolfhounds that had echocardiography performed at dog shows between October 2018 and May 2021. Demographic information, echocardiographic measurements, cardiac rhythm (1-minute lead II rhythm strip), and main diet were recorded retrospectively. Diets were classified as high-pulse or low-pulse based on the presence and location of pulses (peas, lentils, chickpeas, or dry beans) on the ingredient list.

RESULTS

Thirty-five of 97 Irish Wolfhounds (36%) were eating high-pulse diets and 62 of 97 (64%) were eating low-pulse diets. There were no significant differences between diet groups in echocardiographic measurements. A significantly higher percentage of dogs in the high-pulse diet group (6/35 [17%]) had VPCs compared with those in the low-pulse diet group (1/62 [2%]; effect size = 0.15 [95% confidence interval: 0.004-0.31]; P = .005).

CONCLUSIONS AND CLINICAL IMPORTANCE

In this retrospective study of apparently healthy Irish Wolfhounds, high-pulse diets were associated with a higher prevalence of VPCs which could represent early cardiac abnormalities.

Dilated cardiomyopathy in cats: survey of veterinary cardiologists and retrospective evaluation of a possible association with diet

INTRODUCTION/OBJECTIVES

The objectives were to conduct a survey of cardiologists on their recent experiences with cats that have dilated cardiomyopathy (DCM) and to retrospectively review individual cases of feline DCM.

ANIMALS, MATERIALS AND METHODS

Part one: A survey was distributed to cardiologists with questions regarding caseload and clinical management of cats with DCM diagnosed over the past two years. Part two: Cardiologists completing the survey were invited to submit data from cats recently diagnosed with DCM. Data on signalment, clinical signs, diet, echocardiographic measurements and outcome were recorded.

RESULTS

Part one: From 52 completed surveys, many cardiologists responded that measuring and supplementing taurine and recommending a diet change in cats with DCM are common practices. Few (15%) cardiologists reported an increase in the number of feline DCM cases over the past two years, although some had cases that improved even if taurine deficiency was not present. Part two: Twenty of 37 (54%) cats ate low pea/lentil (low PL) diets, and 14/37 (38%) ate high PL diets at the time of diagnosis; three had incomplete diet information. Two of 13 cats (15%) in which taurine was measured had levels below the reference range. After adjusting for other variables, cats eating high PL diets that changed diets after diagnosis had a significantly longer survival time than that of cats eating high PL diets that did not change diets after diagnosis (P = 0.025).

CONCLUSIONS

Additional research is warranted to determine whether there could be a possible association between diet and DCM in cats.

Echocardiographic and electrocardiographic evaluation of North American Irish Wolfhounds

Background

Cardiac disease is an important cause of morbidity and mortality in Irish Wolfhounds (IWs), but its prevalence and clinical characteristics in North American IWs are incompletely described.

Hypothesis/Objectives

That atrial fibrillation (AF) is a diagnostic marker of echocardiographic abnormalities, and that clinical characteristics predict development of IW cardiomyopathy (IWCM). To define the prevalence of arrhythmias and echocardiographic abnormalities in North American IWs.

Animals

Six hundred and forty‐five adult IWs presented for screening examinations intended to identify familial cardiac disease.

Methods

In this retrospective cohort study, reference intervals defined based on echocardiographic data from IW classified as normal, were used to define the prevalence of structural and functional abnormalities. A logistic model was developed to identify clinical findings that predict future development of IWCM.

Results

The prevalence of AF was 8.9% (95% confidence interval [CI], 6.6‐11.2) of which 55.5% had echocardiographic abnormalities. IWCM defined by left atrial enlargement, left ventricular dilatation, and systolic dysfunction had a prevalence of 1.8% (0.72‐2.8). Positive and negative likelihood ratios for AF in the identification of IWCM were, respectively, 10.8 (7.29‐16) and 0.2 (0.06‐0.69). Multivariable logistic regression identified AF (odds ratio [OR]; 10.6, 95% CI, 2.67‐42.3) and male sex (OR; 3.8, 95% CI, 1.02‐14) as predictors of future development of IWCM.

Conclusions and Clinical Importance

Atrial fibrillation is common in North American IW. It occurs in association with structural cardiac disease but also in its absence. Irish Wolfhounds cardiomyopathy is characterized by chamber enlargement but minimally decreased ejection phase indices of myocardial function. Atrial fibrillation is a risk factor for future development of IWCM.

Pedigree analysis of atrial fibrillation in Irish wolfhounds supports a high heritability with a dominant mode of inheritance

Background

Atrial fibrillation (AF) is the most common arrhythmia in dogs. The Irish Wolfhound breed has a high prevalence of AF making them an ideal breed to investigate possible genetic contributions to this disease. The aim of this study was to perform a heritability analysis in North American Irish Wolfhounds using phenotype data from cardiac screenings performed between 2000 and 2019 in order to determine how much of this disease can be attributed to genetics compared to environmental causes. The second aim was to determine the disease mode of inheritance to help inform prevention and breeding practices.

Results

There were 327 Irish Wolfhounds diagnosed with AF and 136 Irish Wolfhounds over 8 years of age without AF. The estimated mean (95% confidence interval) heritability of AF in Irish Wolfhounds was 0.69 (0.50–0.86). The pedigree was consistent with a dominant mode of inheritance.

Conclusion

Results of this study indicate a strong genetic contribution to AF in Irish Wolfhounds and suggest that future research to identify causative genetic mutations is warranted.

Successful balloon angioplasty of pulmonary artery stenosis in two cats and associated complications

Two cats (2.5 months and 8 months old) were each evaluated due to a loud systolic murmur, and each was diagnosed with severe pulmonary artery stenosis at the bifurcation of the main pulmonary artery. Echocardiograms confirmed significant right atrial dilation and right ventricular dilation and/or hypertrophy that was progressive in one cat. Atenolol was initiated and the cats were referred for interventional therapy. Balloon angioplasty was performed via the jugular vein. In case 1, the pressure gradient across the stenosis was reduced from 169.7 mmHg to 23.6 mmHg and 52.4 mmHg across the left and right branch pulmonary arteries, respectively. In case 2, the stenotic echocardiographic gradient was reduced from 64 mmHg to 38.0 mmHg and 35.3 mmHg across the left branch and right-branched pulmonary arteries respectively. Both patients developed moderate to severe dynamic right ventricular outflow tract obstruction post angioplasty. Case 2 developed hypotension, desaturation, and ventricular arrhythmias intra-operatively. Case 1 was discharged but appeared to develop acute lung perfusion injury approximately 36 h after procedure that was manifested by radiographic pulmonary congestion and pulmonary infiltrate of the left lung fields. The congestion was successfully managed medically. Serial echocardiograms over the following 4 years in case 1 showed near complete resolution of the stenosis and associated right heart enlargement.

Measurement of M-mode echocardiographic parameters in healthy adult Maine Coon cats

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.