Left Ventricular Spherical Remodeling and Apical Myocardial Relaxation: Cardiovascular MR Imaging Measurement of Myocardial Segments

Abstract

To prospectively evaluate left ventricular (LV) shape and regional relaxation to determine if rapid, early relaxation of the LV is lost with spherical remodeling of the LV. This HIPAA-compliant study was approved by the institutional review board. All participants gave written informed consent. Cardiovascular magnetic resonance (MR) imaging and transthoracic echocardiography (TTE) were performed in 18 individuals. Each participant was classified into one of three groups according to LV shape and TTE-derived mitral filling parameters. Pairwise comparisons of cardiovascular MR imaging measurements of LV relaxation were made between healthy individuals and those with spherically shaped LVs. The LV regional relaxation rates were determined in a total of 108 basal, middle, and apical myocardial segments in 18 participants (13 women, five men; age range, 35-76 years). Participants with a spherically shaped LV (sphericity index, <1.5) and a mitral inflow velocity E wave/A wave ratio of less than 1.0 exhibited apical thinning velocities that were lower than those of healthy individuals (sphericity index, > or =1.5) (P < .01). The ratio of LV relaxation velocities in the apical versus middle LV segments correlated significantly with sphericity index (R(2) = 0.53; P = .0005). LV apical relaxation velocities in participants with LV spherical remodeling (sphericity index, <1.5) were reduced compared with those of healthy individuals (sphericity index, > or =1.5).