Left Ventricular Wall Stress Is Sensitive Marker of Hypertrophic Cardiomyopathy With Preserved Ejection Fraction

Figure 1. Segmented two-dimensional three-chamber long-axis magnetic resonance images (top row) and color representation of 2D curvature with range [−0.2, 0.2] (bottom row) in (A) a 37-year-old female control subject; (B) a 67-year-old female patient; (C) a 60-year-old female patient; and (D) a 55-year-old female patient. The curvature is negative if the unit tangent rotates clockwise.

Figure 2. Columns: normal subject, HCM patient with sigmoid subtype, HCM patient with reverse curvature subtype and HCM patient with neutral subtype. In (A), first row: segmented two-dimensional cine four-chamber magnetic resonance images at ED phase; second row: wall thickness (range: 4–18 mm) at ED phase; third row: regional curvedness (range: 0.02–0.06 mm−1) at ED phase; last row: wall stress index (range: 0.4–2.7) at ED phase. The order in (B) at ES phase is the same as the order in (A) with wall thickness range: 5–22 mm, regional curvedness range: 0.04–0.08 mm−1 and wall stress index range: 0.2–1.0. HCM, hypertrophic cardiomyopathy; ED, end diastole; ES, end systole.

Figure 3. (A,B) Comparison of wall thickness at end diastole (left) and end systole (right); (C,D) Comparison of curvedness at end diastole (left) and end systole (right); (E,F) Comparison of wall stress index at end diastole (left) and end systole (right); (G,H) Comparison of area strain (left) and ejection fraction (right) between control group and patient group with hypertrophic cardiomyopathy. *Significant difference between two groups (P < 0.05).

Figure 4. Receiver operating characteristic (ROC) curves for left ventricle ejection fraction (LVEF), area strain, and three dichotomized parameters IVSd >13mm, WTED,max >13 mm, σi,ED < 1.64. IVSd, interventricular septum in diastole from 2D clinical CMR measurement; WTED,max, maximal wall thickness among 16 regional segments in diastole from 3D model; σi,ED, wall stress index at end diastole.

Figure 5. Correlation between wall thickness and wall stress index at end diastole.

Figure 6. Error bar plots (mean ± SD) between control and quartiles divided by left ventricular end-diastolic wall thickness in patients with hypertrophy cardiomyopathy. First row: wall thickness at ED (left) and ES (right), ED = end diastole; ES = end systole; second row: 3D regional curvedness at ED (left) and ES (right); third row: wall stress index at ED (left) and ES (right); last row: area strain (left) and ejection fraction (right). *Significant difference between control group and four quartiles (P < 0.05).