Bifid-E Wave: A Novel Doppler Marker of Advanced Mitral Prolapse and Disproportionate Left Ventricular Enlargement

Background: Mitral valve prolapse (MVP) is a relatively common valvular disease initially assessed using transthoracic echocardiography. We identified a novel mitral inflow Doppler signal—bifid-E wave—in patients with MVP. Objectives: The authors postulated that the bifid-E wave is predominantly present in bileaflet prolapse (BLP), representing the displaced prolapse volume in early diastole. We investigated this further to identify its determinants and associated parameters using cardiac magnetic resonance imaging. Methods: This is a cross-sectional study where we analyzed 134 patients divided equally between BLP and single leaflet prolapse (SLP). Cardiac magnetic resonance was used to assess chamber volumes, mitral regurgitation (MR), and prolapse volume. Transthoracic echocardiography was used to determine single vs bifid-E wave morphology. Multivariable analysis was performed to identify the parameters associated with the bifid-E wave. Results: Patients with BLP had a larger prolapse volume, total MR volume, and left ventricular (LV) volume compared to SLP. Bifid-E wave was more prevalent in BLP vs SLP (33% vs 6%). Additionally, bifid-E wave patients were more likely to have BLP. When compared to single-E wave, patients with bifid-E had a larger prolapse volume but similar total MR and LV volumes; however, disproportionate LV enlargement (enlarged LV with mild MR) was more prevalent in bifid-E wave patients. On multivariable analysis, parameters associated with the bifid-E were LV replacement fibrosis, prolapse volume, and disproportionate LV enlargement. Finally, the bifid-E wave was the sole parameter associated with MVP-related fibrosis. Conclusions: We identified a novel mitral Doppler sign that could represent an echocardiographic marker of advanced MVP with a large regurgitant volume and more myocardial fibrosis.