• Daisuke Onohara, Daniella M Corporan, Takanori Kono, Sandeep Kumar, Robert A Guyton, and Muralidhar Padala.
• Structural Heart Research & Innovation Laboratory, Carlyle Fraser Heart Center, Emory University Hospital Midtown, Atlanta, Ga.
• J. Thorac. Cardiovasc. Surg. 2022 May 1; 163 (5): e343e355e343-e355.

ObjectiveThe left ventricle remodels from an ellipsoidal/conical shape to a spherical shape after a myocardial infarction. The spherical ventricle is inefficient as a pumping chamber, has higher wall stresses, and can lead to congestive heart failure. We sought to investigate if restoring physiological ventricular shape with a beating heart implant improves pump function.MethodsRats were induced with a myocardial infarction, developing left ventricular dilatation and dysfunction, and becoming spherical over 3 weeks. Thereafter, they were randomized to undergo left ventricular reshaping with a beating heart implant (n = 19) or continue follow-up without an implant (n = 19). Biweekly echocardiography was performed until 12 weeks, with half the rats euthanized at 6 weeks and remaining at 12 weeks. At termination, invasive hemodynamic parameters and histopathology were performed.ResultsAt 3 weeks after the infarction, rats had a 22% fall in ejection fraction, 31% rise in end diastolic volume, and 23% rise in sphericity. Transventricular implant reshaping reduced the volume by 12.6% and sphericity by 21%, restoring physiologic ventricular shape and wall stress. Over the 12-week follow-up, pump function improved significantly with better ventricular-vascular coupling in the reshaped hearts. In this group, cardiomyocyte cross-section area was higher and the cells were less elongated.ConclusionsReshaping a postinfarction, failing left ventricle to restore its physiological conical shape significantly improves long-term pump function.Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

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