Will the real ventricular architecture please stand up?

Figures

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  Figure 1. Rat heart. Left panel shows color‐coded helix angles, and right panel shows actual helix angles. These were confirmed by histological measurements. The change in angles is continuous, even though the color‐coding shows sharp transitions. Reproduced with permission from Chen et al. Remodeling of cardiac fiber structure after infarction in rats quantified with diffusion tensor MRI. Am J Physiol Heart Circ Physiol 285: H946–954, 2003.

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  Figure 2. Rotation and twist, as seen looking at the heart from the apex. The larger circle and solid arrow represent the base, and the smaller circle and dashed arrow represent the apex. Left panel: Both apex and base rotate in the same direction; therefore no twist. Right panel: Base rotates clockwise and the apex rotates counterclockwise, producing twist.

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  Figure 3. Activation of helical fibers when the two ends are fixed. There will be twist but the distance between the two ends remains the same.

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  Figure 4. Electrical activation and shortening times. Reproduced with permission from Ashikaga et al. Transmural dispersion of myofiber mechanics: implications for electrical heterogeneity in vivo. J Am Coll Cardiol 49: 909–916, 2007.

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  Figure 5. Twist diagram. IVC‐isovolumic preejection period; EJEC‐ejection; IPE‐isovolumic postejection period; DIAS‐mid and ‐late diastole.