Left atrial deformation and phasic function determined by two-dimensional speckle-tracking echocardiography in dogs with myxomatous mitral valve disease

Abstract Introduction: Left atrial (LA) function can provide useful information in dogs with myxomatous mitral valve disease (MMVD). Recently, we have demon- strated the feasibility of measuring LA longitudinal deformation using speckle- tracking echocardiography (STE) to estimate LA function in healthy dogs. Whether LA strain and strain rate variables provide additional information about LA function and clinical cardiac status in dogs with MMVD remains unexplored. Animals: Ninety-six client-owned dogs of different breeds with MMVD were pro- spectively enrolled. Methods: LA longitudinal deformation was evaluated in each dog by STE and differ- ent STE variables were used to assess LA function. Results: No STE variables differed between American College of Veterinary Internal Medicine Stage B1 and B2 dogs but were lower in Stage C dogs. Peak atrial longitu- dinal average strain < 27.9%, left-atrial-to-aortic ratio > 2.2 and peak atrial contraction average strain < 7.25% discriminated symptomatic MMVD dogs by recei- ver operating characteristic analysis with sensitivity and specificity of 100% and 100% (95% confidence interval [CI] 91e100%), 92% (95% CI 78e98%) and 98% (95% CI 87e100%), 100% (95% CI 91e100%) and 95% (95% CI 83e99%), respectively. In 12 dogs with similar left-atrial-to-aortic ratio, peak atrial longitudinal average strain and peak atrial contraction average strain differentiated dogs with subclinical dis- ease from those with congestive heart failure (CHF). Conclusion: Dogs with MMVD in CHF appear to have lower LA longitudinal strain and strain rate variables compared with dogs with subclinical disease. Further studies are needed to establish if our initial findings can provide useful information for the diagnosis, treatment, and prognosis of dogs with MMVD.