title: A method to assess endocardial regional longitudinal curvature of the left ventricle.
abstract: Knowledge of the instantaneous geometry of the left ventricular (LV) chamber is necessary to calculate LV function and wall stresses. We describe a method utilizing myocardial markers that does not rely on any a priori assumptions of global LV geometry. Five dogs underwent placement of 25 endocardial and 3 epicardial miniature LV markers. Six weeks later, the animals were studied during conscious closed-chest conditions. The three-dimensional coordinates of the LV markers were used to compute longitudinal fitted curves for LV walls and septum during steady-state conditions; endocardial radii of curvature (rcurv) were then computed for each region at the midequatorial (rcurv-eq) and apical levels. There was a uniform decrease in rcurv in each LV wall during systole (compared with diastole, P < 0.01); at end systole, rcurv was regionally heterogeneous between opposing walls, e.g., anterior and posterior rcurv-eq values were 17.2 +/- 2.0 and 17.7 +/- 1.8 (SD) cm, respectively (P < 0.05). At end diastole, only septal-lateral rcurv-eq was different (16.9 +/- 2.1 vs. 18.7 +/- 1.3 cm: P < 0.05). Normalization of rcurv (to instantaneous LV volume) removed the systolic-diastolic differences, but a similar pattern of regional heterogeneity persisted. The data presented pertain to the LV endocardial surface, but the method described can be applied to the epicardial surface as well; this new method offers promise in assessing dynamic changes in longitudinal LV endocardial curvature.
authors.affiliation: Department of Cardiovascular and Thoracic Surgery, Stanford University School of Medicine 94305, USA.
authors.forename: A
authors.initials: A
authors.lastname: DeAnda
authors.forename: M R
authors.initials: MR
authors.lastname: Moon
authors.forename: S D
authors.initials: SD
authors.lastname: Nikolic
authors.forename: L J
authors.initials: LJ
authors.lastname: Castro
authors.forename: J I
authors.initials: JI
authors.lastname: Fann
authors.forename: G T
authors.initials: GT
authors.lastname: Daughters
authors.forename: N B
authors.initials: NB
authors.lastname: Ingels
authors.forename: D C
authors.initials: DC
authors.lastname: Miller
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003971:Diastole; D004285:Dogs; D006321:Heart / Q000033:anatomy & histology* / Q000502:physiology*; D006339:Heart Rate; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006439:Hemodynamics; D008955:Models, Cardiovascular; D008961:Models, Structural; D008962:Models, Theoretical; D013599:Systole; D016276:Ventricular Function