MSIA · Application of MRI to explore myocardial structural reorganisation accompanying contraction and the influence of this on arrhythmogenesis the normal and post infarct heart

Understanding of normal and abnormal cardiac excitation and contraction requires the integration of knowledge of myocyte electrophysiology and mechanics with knowledge of dynamic myocardial architecture.The myocardium is structured as stacked 4-6 cells thick (~100 µm) laminae of myocytes, which have a complex architectural arrangement throughout the cardiac wall and have localised regions of abrupt change in orientation.Ventricular structure is not an esoteric consideration of form. Along with other functional and structural properties of the myocardium, fibre and laminar architecture determine i) the spread of myocardial activation and ii) the deformation of the wall in contraction. My hypothesis is that: (i) myocardial systolic thickening is enabled by the sliding of sheets over each other, with the laminar architecture serving to limit shear stress