Speckle tracking echocardiography for evaluation of myocardial functions before and after mitral valvuloplasty in dogs

Background: Myxomatous mitral valve disease (MMVD) is the most common acquired heart disease in dogs. Mitral valvuloplasty (MVP) addresses regurgitation, but the pre- and postoperative changes in myocardial function remain uncertain.

Objectives: This study evaluated myocardial motion before and after MVP using two-dimensional speckle-tracking echocardiography (2D-STE).

Animals: Eight client-owned dogs undergoing MVP for MMVD.

Methods: Myocardial deformation was assessed by 2D-STE before surgery and at 1- and 3-months post-surgery. Measurements included left ventricular global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), cardiac twist, and right ventricular free wall GLS (RVFW-GLS).

Results: Postoperative decreases were observed in left ventricular internal dimensions, left atrial size, and early diastolic myocardial velocity, with an increase in peak late diastolic velocity. LV-GLS decreased at 1 month (-14.4%) and 3 months (-16.3%) compared to preoperative values (-24.4%) (p = 0.0078, p = 0.015). GCS decreased at 1 month (-12.9%) and 3 months (-14.8%) compared to preoperative values (-21.7%) (p = 0.0078). GRS decreased at 1 month (27.7%) and 3 months (32.0%) compared to preoperative values (67.7%) (p = 0.0078). No significant changes were observed in RVFW-GLS. Peak systolic twist increased at 3 months (9.1° vs. 4.9°, p = 0.039). Peak systolic apical rotation showed an upward trend at 3 months (p = 0.109). Left ventricular twist was mildly affected by LVIDd, LVIDDN, and sphericity index (R ² = 0.187, p = 0.034; R ² = 0.33, p = 0.0029; R ² = 0.22, p = 0.019).

Conclusions and clinical importance: Postoperative myocardial motion approached reference values, indicating significant improvement, particularly in left ventricular twisting motion. These findings highlight the positive impact of surgery on cardiac function in dogs with MMVD.