Key result
Impaired atrial conduction indices track disease severity and link to arrhythmias in canine MMVD.
Why the study?
Electrocardiographic and echocardiographic indices of atrial conduction and electromechanical activation in dogs with myxomatous mitral valve disease and their association with disease progression were not fully characterized.
Cross-Sectional (n=139)
Single-blind
Yes
Electrocardiographic and echocardiographic indices of atrial conduction lengthen progressively with mitral valve disease severity in dogs, providing non-invasive markers of structural remodeling and arrhythmic risk.
Atrial conduction indices may aid staging and arrhythmia risk assessment in canine MMVD; leaves open their prognostic utility in prospective studies.
This study evaluated electrocardiographic and echocardiographic indices of atrial conduction and electromechanical activation in dogs with myxomatous mitral valve disease and in healthy dogs, and assessed their association with disease stage, cardiac remodeling, heart failure, and supraventricular arrhythmias. A total of 139 small-breed dogs (<15 kg) were included (42 healthy, 50 stage B1, 19 stage B2, and 28 stage C). Atrial electromechanical intervals were measured using tissue Doppler imaging at the lateral mitral, septal mitral, and tricuspid annuli, and electrocardiographic indices including P-wave duration and P-wave dispersion were assessed. Receiver-operating characteristic analysis was performed to evaluate the discriminatory performance of atrial conduction markers. Several electrocardiographic and echocardiographic indices increased across disease stages, with more pronounced differences observed in dogs with advanced disease. A broad range of parameters was associated with cardiac remodeling and heart failure, including P-wave duration across multiple leads and tissue Doppler-derived indices. Among these, P-wave dispersion, septal electromechanical delay (S-PAp), and P-wave duration in selected leads (e.g., lead II and aVF) showed consistent discriminatory performance across outcomes. Dogs with supraventricular arrhythmias showed increased atrial conduction times compared with dogs in sinus rhythm, particularly in electrocardiographic indices and septal electromechanical measurements. Electrocardiographic and echocardiographic indices of atrial conduction provide complementary, non-invasive information on atrial remodeling and electrophysiological alterations in dogs with myxomatous mitral valve disease. In addition, this study establishes reference values for multiple tissue Doppler-derived atrial conduction indices in healthy and myxomatous mitral valve disease–affected dogs. Cite this article as: Vila, B. C. P., & Sousa, M. G. (2026). Atrial conduction times change with progression of mitral valve disease in dogs. Acta Veterinaria Eurasia, 52, 0115, doi: 10.5152/actavet.2026.26115.
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Vila et al. (2026) conducted a cross-sectional in Myxomatous Mitral Valve Disease (MMVD) (n=139). Myxomatous mitral valve disease progression vs. Healthy controls or less severe disease stages was evaluated. In small-breed dogs with myxomatous mitral valve disease, electrocardiographic and echocardiographic atrial conduction indices, including P-wave dispersion, progressively increased with disease severity and were associated with cardiac remodeling, heart failure, and supraventricular arrhythmias.
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