King Kenneth Cheung1,2, Anthony Neil Price2, Johannes Riegler2, Roger J. Ordidge1, Mark Francis Lythgoe2
1Department of Medical Physics and Bioengineering, University College London (UCL), London, UK; 2Centre for Advanced Biomedical Imaging (CABI), Department of Medicine and Institute of Child Health, UCL, London, UK
MRI measurement of in vivo cardiac function has become a popular method to assess treatment effects in small animal models of myocardial infarction (MI). In chronic MI, infarct size has been shown to correlate closely to deterioration in cardiac functions; however, the relationship between infarct size and cardiac contractility in the hyper-acute phase (i.e. hours) following MI is unclear. We aimed to investigate this relationship using cardiac MRI with Gd-DTPA delayed-enhancement and ex vivo myocardial viability assay. Our study suggests a discrepancy between infarct size and reduction of ejection fraction during the early phases of MI. The observed variability in the hyper-acute phase of MI may reflect the presence of myocardial stunning.