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. 2020 Mar;34(2):581-590.
doi: 10.1111/jvim.15709. Epub 2020 Feb 29.

Echocardiographic and Electrocardiographic Evaluation of North American Irish Wolfhounds

Free PMC article

Echocardiographic and Electrocardiographic Evaluation of North American Irish Wolfhounds

William D Tyrrell Jr et al. J Vet Intern Med. .
Free PMC article


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.

Keywords: atrial fibrillation; canine; cardiomyopathy; prevalence.

Conflict of interest statement

Authors declare no conflict of interest.


Figure 1
Figure 1
A flow chart that schematically provides the numbers of IWs subject to screening examinations intended to identify heritable cardiac disease, and the numbers of selected echocardiographic abnormalities identified during the first and during follow‐up examinations. Six hundred and forty‐five IWs initially were screened but because of missing data, 600 could be classified as normal or not. In cases identified on follow‐up, those classified as CM were ones that were not later classified as IWCM. AF, atrial fibrillation; AFlone, lone atrial fibrillation; CM, cardiomyopathy; IWs, Irish Wolfhounds; IWCM, IW cardiomyopathy
Figure 2
Figure 2
Age‐dependent prevalence of atrial fibrillation (left) and Irish Wolfhound cardiomyopathy (right). The x‐axis consists of ordinal categories of age and the y‐axis represents prevalence expressed as percent. Numerical values are the absolute counts of affected and unaffected Irish Wolfhounds in each age category

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