Andrew Atkinson ¹ Weixuan Chen ¹ Abimbola J Aminu ¹ Marcin Kuniewicz ^1,2 Irem Karaesmen ¹ Neal Duong ³ Klaudia Proniewska ² Peter Michael Van Dam ^2,4 Tinen Lee Iles ³ Mateusz K Hołda ^1,2 Jerzy Walocha ² Paul A Iaizzo ³ Michael Alan Colman ⁵ Halina Dobrzynski ^1,2*

• ¹ The University of Manchester, Manchester, United Kingdom
• ² Jagiellonian University Medical College, Kraków, Lesser Poland, Poland
• ³ University of Minnesota Twin Cities, St. Paul, Minnesota, United States
• ⁴ University Medical Center Utrecht, Utrecht, Netherlands, Netherlands
• ⁵ University of Leeds, Leeds, England, United Kingdom

Introduction High-resolution digitised cardiac anatomical data sets are in huge demand in clinical, basic research and computational settings. They can be leveraged to evaluate intricate anatomical and structural changes in disease pathology, such as myocardial infarction (MI), which is one of the most common causes of heart failure and death. Advancements in high-resolution imaging and anatomical techniques in this field and our laboratory have led to vast improvements in understanding cardiovascular anatomy, especially the cardiac conduction system (CCS) responsible for the electricity of the heart, in healthy/aged/obese post-mortem human hearts. However, the digitised anatomy of the electrical system of the heart within MI hearts remains unexplored. Methods Five post-mortem non-MI and MI human hearts were obtained by the Visible Heart® Laboratories via LifeSource, Minneapolis, MN, USA (with appropriate ethics and consent): specimens were then transported to Manchester University with an material transfer agreement in place and stored under the HTA 2004, UK. After performing contrast-enhanced micro-CT, a visualisation tool (namely Amira) was used for 3D high-resolution anatomical visualisations and reconstruction. Various cardiovascular structures were segmented based on the attenuation difference of micro-CT scans and tissue traceability. The relationship between the CCS and surrounding tissues in MI and non-MI human hearts was obtained. 3D anatomical models were further explored for their use in computational simulations, 3D printing and mix/virtual reality visualisation. Results 3D segmented cardiovascular structures in the MI hearts elicited diverse macro-/micro- anatomical changes. The key findings are thickened valve leaflets, formation of new coronary arteries, increased or reduced thicknesses of pectinate and papillary muscles and Purkinje fibres, thinner left bundle branches, sinoatrial nodal atrophy, atrioventricular conduction axis fragmentation, and increased epicardial fat in some hearts. The propagation of the excitation impulses can be simulated, and 3D printing can be utilised from the reconstructed and segmented structures. Discussion High-resolution digitised cardiac anatomical datasets offer exciting new tools for medical education, clinical applications, and computational simulation.