Spatial and Temporal Inhomogeneity of Left Ventricular Myocardial Transmural Strains During Diastole
(English)Manuscript (preprint) (Other academic)
Rapid early filling requires a rapid shift to a very compliant left ventricle immediately after systole, allowing filling at low driving pressures. This compliance shift is manifested as changes in transmural strains: however its mechanistic basis is incompletely understood. Seven adult Dorsett hybrid sheep were anesthetized and radiopaque markers were surgically implanted to silhouette the LV chamber. Three transmural columns of four beads each were implanted into the lateral equatorial LV wall. Eight weeks after surgery, biplane videofluoroscopic images of all radiopaque markers were acquired at 60 Hz horn dosed-chest anesthetized animals. After data acquisition, hearts were arrested at the end-diastolic pressure aud quantitative hist.ology was used to determine fiber and sheet angles. Lagrangian strains in cardiac and liber-sheet coordinates were computed at end of early filling and end diastole with filling onset as reference at three transmural depths. Rapid early filling was dominated by subepicardial circumferential stretching (ECC=0.08±0.02) and fiber lengthening (Eƒƒ=0.03±0.01), midwall circumferential stretching (ECC=0.07±0.02), and subendocardial wall thinning (ERR=-0.05±0.01). Subepicardial strains achieved their ED values during early diastole, while mid wall and subendocardial straius reset during late diastole. Sheet-normal shear strain was a dominant contributor to wall thinning during diastole.
cardiac strains, fiber-sheet strains, sheep, LV filling
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-100800OAI: oai:DiVA.org:liu-100800DiVA: diva2:663733