Função sistólica em cães com doença mixomatosa da valva mitral: avaliação ecocardiográfica comparativa pelos métodos Simpson, Modo-M e Speckle tracking

Abstract

The myxomatous mitral valve disease (MMVD) is the most common acquired heart disease in dogs and the leading cause of congestive heart failure (CHF). The conventional echocardiographic indexes for systolic analysis, such as the Simpson and M mode methods, suffer interference from preload and afterload, making the detection of myocardial dysfunction in the presence MMVD challenging. For this reason, we introduced the two-dimensional speckle tracking (2D-STE), although there are no studies to date which assessed the systolic parameters, such as ejection fraction, systolic and diastolic volume indexes, and ejection fraction (EF) using this technique on healthy and MMVD dogs. Thus, the objective of this study was to compare these parameters using different methods for assessing the systolic function on healthy dogs and on those with different stages of MMVD. We selected 35 dogs, with 9 being clinically healthy (control group), 8 with MMVD without cardiac remodeling (group B1), 7 with MMVD and cardiac remodeling without CHF (group B2) and 11 MMVD and ICC (group C) were selected. The results found in the left ventricular diastolic volume index (EDVI) were higher in the Simpson method when compared to the 2D-STE, since the left ventricular systolic volume index values (ESVI) were higher in the 2D-STE method. We found higher shortening fractional (SF) values for the M Mode when compared to the 2D-STE, for the Control, B1 and B2 groups, while for group C, similar values were found. The ejection fraction values were lower for the 2D-STE method when compared to the Simpson and M mode methods. We may conclude that the 2D-STE method, although feasible, did not present values statistically similar to those of the techniques already established for calculating FE, SF and ventricular volume indexes, requiring further studies to validate the values for dogs with MMVD.