Pneumatic Distension of Ventricular Mural Architecture Validated Histologically

• Published in: RöFo : Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebende Verfahren Vol. 188; no. 11; pp. 1045 - 1053
• Main Authors: Burg, M. C., Lunkenheimer, P., Niederer, P., Brune, C., Redmann, K., Smerup, M., Spiegel, U., Becker, F., Maintz, D., Heindel, W., Anderson, R. H.
• Format: Journal Article
• Language: English
• Published: Stuttgart · New York Georg Thieme Verlag KG 01.11.2016
• Subjects: Animals; Cardioplegic Solutions - administration & dosage; Heart; Heart Ventricles - cytology; Heart Ventricles - diagnostic imaging; Heart Ventricles - drug effects; In Vitro Techniques; Myocardial Contraction - drug effects; Myocardial Contraction - physiology; Myocytes, Cardiac - cytology; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - physiology; Pressure; Swine; Tomography, X-Ray Computed - methods; Ventricular Function, Left - drug effects; Ventricular Function, Left - physiology; animal models; heart CT; myocardium; myocardial function; ventricular stucture; heart anatomy & histology
• ISSN: 1438-9029; 1438-9010
• DOI: 10.1055/s-0042-115569

Abstract Purpose: There are ongoing arguments as to how cardiomyocytes are aggregated together within the ventricular walls. We used pneumatic distension through the coronary arteries to exaggerate the gaps between the aggregated cardiomyocytes, analyzing the pattern revealed using computed tomography, and validating our findings by histology. Methods: We distended 10 porcine hearts, arresting 4 in diastole by infusion of cardioplegic solutions, and 4 in systole by injection of barium chloride. Mural architecture was revealed by computed tomography, measuring also the angulations of the long chains of cardiomyocytes. We prepared the remaining 2 hearts for histology by perfusion with formaldehyde. Results: Increasing pressures of pneumatic distension elongated the ventricular walls, but produced insignificant changes in mural thickness. The distension exaggerated the spaces between the aggregated cardiomyocytes, compartmenting the walls into epicardial, central, and endocardial regions, with a feathered arrangement of transitions between them. Marked variation was noted in the thicknesses of the parts in the different ventricular segments, with no visible anatomical boundaries between them. Measurements of angulations revealed intruding and extruding populations of cardiomyocytes that deviated from a surface-parallel alignment. Scrolling through the stacks of tomographic images revealed marked spiraling of the aggregated cardiomyocytes when traced from base to apex. Conclusion: Our findings call into question the current assumption that cardiomyocytes are uniformly aggregated together in a tangential fashion. There is marked heterogeneity in the architecture of the different ventricular segments, with the aggregated units never extending in a fully transmural fashion. Key Points: • Pneumographic computed tomography reveals an organized structure of the ventricular walls. • Aggregated cardiomyocytes form a structured continuum, with marked regional heterogeneity. • Global ventricular function results from antagonistic forces generated by aggregated cardiomyocytes. Citation Format: • Burg MC, Lunkenheimer P, Niederer P et al. Pneumatic Distension of Ventricular Mural Architecture Validated Histologically. Fortschr Röntgenstr 2016; 188: 1045 – 1053