title: Finite strains in anterior and posterior wall of canine left ventricle.
abstract: Piezoelectric crystals were implanted in the anterior and posterior midwall of the left ventricle in six anesthetized dogs to compare regional two-dimensional finite deformations. Increasing left ventricular end-diastolic pressure (LVEDP) from 3 to 18 mmHg caused a similar expansion in the end-diastolic configuration (similar end-diastolic principal strains), but maximal lengthening was more circumferential in the anterior wall (-18 +/- 13 degrees) and more longitudinal in the posterior wall (-54 +/- 19 degrees). End-diastolic in-plane shears were negative in both regions, consistent with a left-handed diastolic torsion. As LVEDP increased, maximal shortening strains increased similarly (similar end-systolic principal strains), but there was a preferential increase in end-systolic circumferential strain in the anterior wall and preferential increase in longitudinal strain in the posterior wall. End-systolic in-plane shears were small and positive in both regions. The circumferential strain accurately reflected maximal end-diastolic and end-systolic principal strains in the anterior wall at mid and high LVEDP but underestimated the maximal end-diastolic principal strain by 50% and the maximal end-systolic principal strain by 30% in the posterior wall at all LVEDPs. We conclude that the magnitude of end-diastolic and end-systolic strains is similar for anterior and posterior walls over a wide range of LVEDP. However, there are regional differences in the directions of maximal deformation that should be considered when evaluating regional ventricular function.
authors.affiliation: Department of Medicine, Veterans Administration Medical Center, San Diego, California.
authors.forename: F J
authors.initials: FJ
authors.lastname: Villarreal
authors.forename: W Y
authors.initials: WY
authors.lastname: Lew
mesh_terms: D000818:Animals; D003971:Diastole; D004285:Dogs; D006321:Heart / Q000502:physiology*; D006352:Heart Ventricles; D008955:Models, Cardiovascular; D013599:Systole