Late systolic onset of regional LV relaxation demonstrated in three-dimensional space by MRI tissue tagging

Boaz D. Rosen, Bernhard L. Gerber, Thor Edvardsen, Ernesto Castillo, Luciano C. Amado, Khurram Nasir, Dara L. Kraitchman, Nael F. Osman, David A. Bluemke, João A.C. Lima

Research output: Contribution to journalArticle

Abstract

Left ventricular (LV) relaxation entails myocardial deformation that induces LV filling. Yet, the precise mechanisms of the earliest changes in tissue properties that characterize myocardial relaxation remain incompletely understood. Ten healthy volunteers (seven males), 25-43 yr, underwent tagged and cine MRI with high temporal resolution (25-35 ms). Normal strains including radial (Err), circumferential (Ecc), and longitudinal (Ell) strains, shear strains including Ecl (circumferential-longitudinal), Ecr (circumferential-radial), and Erl (radial-longitudinal), and principal strains (E1, E2, and E3) were calculated using a displacement field-fitting method. Temporal changes in angular strains indicative of shear and torsion release and normal strains were studied during late systole and early relaxation. The onset of individual relaxation strains was heterogeneous relative to LV filling. Shear strains (Ecr, Erl, and Ecl) and radial thinning were first to develop. Times of onset of Ecr, Erl, Ecl, and Err occurred 108, 93, 67, and 73 ms before aortic valve closure, respectively. Ell, Ecc, and LV volume change commenced significantly later after the onset of diastolic shear strains and radial thinning. The onset of E cc, Ell, and LV volume change was noted 38 ms before aortic valve closure (P < 0.05 relative to the onset of shear strains and Err). Myocardial relaxation is characterized by a three-dimensional unfolding deformation that includes release of torsion, shear, and radial thinning beginning before aortic valve closure. This unfolding pattern precedes longitudinal and circumferential elongation and may facilitate early diastolic filling.

Original languageEnglish (US)
Pages (from-to)H1740-H1746
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume287
Issue number4 56-4
DOIs
StatePublished - Oct 2004

Keywords

  • Diastole
  • Magnetic resonance imaging
  • Shear
  • Strain
  • Ventricle

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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