Electromechanical Wave Imaging for pediatric mitral valve disease characterization in the clinic

Clinical echocardiography for Mitral Valve (MV) prolapse diagnosis is operator-dependent, qualitative, and unobservant of present electromechanical issues. A timely electrical activation of the MV, following atrial and preceding ventricular activation, of the left-ventricular (LV) papillary muscles (PMs) and adjacent tissue prevents MV prolapse (MVP) and undesired regurgitation (MR). This study assesses the activation of the MV region using echocardiography-based Electromechanical Wave Imaging (EWI). One open-chest healthy mongrel canine was imaged with 2D EWI in apical views on a Vantage 256 and 3-lead ECG recording. Five MVP pediatric subjects of varying MR and five age-matched controls were imaged in the clinic with the same sequence. 2D and 3D rendered EWI ventricular activation isochrones were generated for the canine and human study, respectively. Mean EM activation times for the canine MV and pediatric LV walls for mid, basal, and apical segments are calculated. Mid-LAT/mid-POST walls concur with the anterolateral (AL)/ posteromedial (PM) LV PMs, and full LAT and POST walls form the surrounding tissue. EWI successfully imaged the MV EM activation across all views in both studies. A mean MV EM activation delay of 83.57 ms (82 ms electrical value, .02% error) was interjected between atrial and ventricular activation. In the clinic, MVP subjects exhibited later LAT and POST wall EM activation against controls. Mean MVP EM activation was higher across all subjects in the AL-PM and PM-PM LV mid-level regions. We introduced a first-of-its-kind, novel approach for MV EM activation imaging and MVP detection in vivo, illustrating the electrical and valvular cardiac system interconnectivity, and providing a more holistic and objective diagnosis of electromechanical heart valve disease with echocardiography.