1. Effects of mitral valve replacement on regional left ventricular systolic strain 
Marc R Moon, MD, Abe DeAnda, MD, George T Daughters, MS, Neil B Ingels, PhD, D.Craig Miller, MD 
The Annals of Thoracic Surgery 
Volume 68, Issue 3, Pages (September 1999)
DOI: /S (99)

2. Fig 1
Myocardial marker array inserted to measure left ventricular (LV) volume and regional LV strain. Subepicardial markers were inserted in the apical (below the level of papillary muscle insertion), equatorial, and bassal LV plances along eight meridians; anterior (from the origin of the left anterior descending coronary artery to the apex), anterolateral, lateral (obtuse margin), posterolateral, posterior (inferior wall along the posterior descending artery), posteroseptal, septal, and anteroseptal. One marker was also placed at the apex.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

3. Fig 2
Myocardial fiber orientation in the left ventricle proceeds from a left-handed helix in the subepicardium (group I) to a right-handed helix in the subendocardium (group III); midwall fibers are oriented circumferentially (group II). Although there are no longitudinal fibers per se (group IV), combined contraction of the oblique subepicardial and subendocardial fibers will decrease the base to apex dimension.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

4. Fig 3
Determination of angular groups for the anterior region. (A) A reference system for each region (anterior region in this example) was defined. A reference long axis was defined by connecting the apex marker with the midpoint of the septal and lateral basal markers (midbase), and a reference plane was defined by these markers. (B) Chords were then constructed from the central reference marker (anterior equatorial marker in this example) to its surrounding markers (basal, equatorial, and apical markers in the septal, anteroseptal, anterior, anterolateral, and lateral walls in this example). Angles were measured relative to an imaginary line (through the central marker) perpendicular to the reference long axis (not pictured). The chords were then assigned to one of the four angular groups: group IV chords (longitudinal) were within 27.5° of the reference axis; group II chords (circumferential) were within 27.5° of a line perpendicular to the reference axis; and groups I and III chords were oriented obliquely between groups II and IV. Angular groups II and IV are shaded for clarity.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )

5. Fig 4
Effects of: (A) sham mitral valve replacement (MVR) (n = 6); (B) anterior chordal-sparing MVR (n = 7); (C) posterior chordal-sparing MVR (n = 7); and (D) conventional MVR (n = 7) on regional left ventricular systolic chord shortening (strain). Data bars represent the difference in regional LV strain from pre-MVR to post-MVR for each angular group and region. Dark bars represent significant changes, whereas light bars represent insignificant changes (mean ± one standard error of the mean). +p < 0.05 pre-MVR versus post-MVR. Angular groups: I, left-handed oblique (subepicardial); II, circumferential; III, right-handed oblique (subendocardial); IV, longitudinal. A, anterior; L, lateral; P, posterior; S, septal.
The Annals of Thoracic Surgery  , DOI: ( /S (99) )