Heart muscle function changes in dogs after mitral valve surgery

Abstract

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%) ( = 0.0078, = 0.015). GCS decreased at 1 month (-12.9%) and 3 months (-14.8%) compared to preoperative values (-21.7%) ( = 0.0078). GRS decreased at 1 month (27.7%) and 3 months (32.0%) compared to preoperative values (67.7%) ( = 0.0078). No significant changes were observed in RVFW-GLS. Peak systolic twist increased at 3 months (9.1° vs. 4.9°, = 0.039). Peak systolic apical rotation showed an upward trend at 3 months ( = 0.109). Left ventricular twist was mildly affected by LVIDd, LVIDDN, and sphericity index ( = 0.187, = 0.034; = 0.33, = 0.0029; = 0.22, = 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.