Risk factors for atrial fibrillation in dogs with dilated cardiomyopathy

Abstract

IntroductionAtrial fibrillation secondary to dilated cardiomyopathy (DCM) frequently affects large-breed dogs. The aim of the present study was to identify risk factors for the development of atrial fibrillation in dogs of different breeds with an echocardiographic diagnosis of DCM.MethodsIn this multicenter retrospective study, we searched the electronic databases of five cardiology referral centers for dogs with an echocardiographic diagnosis of DCM. A comparison of clinical and echocardiographic variables was performed between dogs developing atrial fibrillation and those not developing atrial fibrillation and the ability to distinguish between these two groups of dogs was evaluated by receiver operating characteristic curve analysis. Univariate and multivariable logistic regression analysis estimated the odds ratio (OR) with 95% confidence interval (CI) of developing atrial fibrillation.ResultsWe included 89 client-owned dogs with occult and overt echocardiographic DCM. Of these, 39 dogs (43.8%) had atrial fibrillation, 29 dogs (32.6%) maintained a sinus rhythm, and 21 dogs (23.6%) showed other cardiac arrhythmias. Left atrial diameter had high accuracy (area under the curve = 0.816, 95% CI = 0.719–0.890) to predict the development of atrial fibrillation at the cut-off of >4.66 cm. After multivariable stepwise logistic regression analysis, only increased left atrial diameter (OR = 3.58, 95% CI = 1.87–6.87; p < 0.001) and presence of right atrial enlargement (OR = 4.02, 95% CI = 1.35–11.97; p = 0.013) were significant predictors of atrial fibrillation development.DiscussionAtrial fibrillation is a common complication of DCM in the dog and is significantly associated with increased absolute left atrial diameter and right atrial enlargement.

Risk Factors for Atrial Fibrillation in the Dog: A Systematic Review

“…Notably, cardiovascular disorders, in particular valvular disease, exhibit relevance across both species. However, other factors integral to human AF, such as health behaviors (e.g., smoking tobacco and alcohol intake) and broader health factors (e.g., height, concurrent non-cardiac disorders), are either not applicable or have been inadequately investigated in the canine population [ 4 , 5 ].…”

“…In humans, recognized risk factors for incident AF include genetics, advanced age, male sex, and Caucasian ethnicity [ 11 ]. In dogs, many studies have reported a higher prevalence of AF in large-breed animals [ 1 , 5 , 6 , 9 , 10 , 11 , 16 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Notably, a high heritability estimate for AF, with a likely dominant mode of inheritance, has been demonstrated specifically in Irish Wolfhounds [ 29 ].…”

“…However, genetic studies in other commonly affected canine breeds are currently lacking. The observed higher prevalence of AF in large-breed dogs appears to be linked to their predisposition to DCM rather than a specific genetic predisposition for the arrhythmia [ 3 , 5 ].…”

“…Concerning sex, earlier reports lacking specific statistical analyses suggested a higher likelihood of AF in male dogs [ 1 , 8 , 16 , 17 , 24 , 25 ]. However, recent studies employing rigorous statistical tests, such as multivariable logistic regression models, indicate that male sex is not a direct risk factor for AF in dogs, unlike in humans [ 4 , 5 , 30 , 31 ]. The previously reported prevalence of AF in male dogs is likely associated with their predisposition to acquired heart diseases, such as MMVD or DCM [ 6 , 33 ].…”

“…This prevalence varies significantly among breeds, ranging from 0.04% in Miniature Poodles to 8.9% in Irish Wolfhounds [ 1 , 2 , 3 ]. Differences also emerge concerning underlying cardiac diseases, with prevalence ranging from 2.7% to around 45% in dogs with myxomatous mitral valve disease (MMVD) and dilated cardiomyopathy (DCM), respectively [ 4 , 5 , 6 ]. While some dogs may develop AF without an apparent underlying cardiac disease (referred to as primary or lone AF) [ 3 , 7 ], this arrhythmia typically arises secondary to canine cardiac diseases that induce left atrial remodeling [ 3 , 7 , 8 ].…”