Avaliação da função atrial esquerda por meio da ecocardiografia speckle tracking bidimensional em cães com degeneração mixomatosa da valva mitral

Abstract

Echocardiography is considered one of the most important diagnostic methods in veterinary cardiology. Thus, new tools such as two-dimensional speckle tracking (2D-STE) have been used in veterinary medicine for quantification of ventricular myocardial function. However, there is little information about the use of this tool for assessment of left atrial function in dogs. Given that, as myxomatous mitral valve disease (MMVD) is one of the most common heart disease in dogs, the aim of this study was to evaluate the left atrial function in dogs of various classifications of MMVD by means the achievement of the variables of atrial myocardial deformation strain (St) and strain rate (StR), atrial systolic and diastolic volume indices (iVsA and iVdA, respectively), cardiac index (iCA) and ejection fraction (FEA) obtained by 2D-STE. For this purpose, were evaluated 33 dogs divided into 4 groups according to the classification of MMVD as follows, control (n = 8), B1 (n = 10), B2 (n = 8), C/D (n = 7), respectively. For the variable St were observed the following values, Control: 26.05 ± 8.88; B1: 20.22 ± 9.93; B2: 18.93 ± 7.58 and C/D: 16.14 ± 7.39. Also, a negative correlation (r = -0.287; P = 0.018) between the ratio of the diameter of the left atrium to the aorta (Ae/Ao) and the global St was observed. Regarding the variables iVdA, IVsA, iCA, they were positively correlated (r = 0.331, P = 0.020; r = 0.335, P = 0.020; r = 0.374, P = 0.011, respectively) with the Ae/Ao ratio and the FEA showed a negative correlation (r = -0.392; P = 0.008). In addition, these variables were also obtained by Simpson's method, being both methods were compared, and there was no difference between them. This study shows that the 2D-STE has great potential for use in the evaluation of dogs with MMVD. Furthermore, the study provides new insights into the assessment of left atrial function in dogs with MMVD.