Using Magnanese-Enhanced MRI to Monitor the Efficacy of Angiotensin Converting Enzyme Inhibitor Treatment in a Murine Myocardial Infarction

Introduction: The ischemically injured myocardium contains a mixture of viable and non-viable tissue post-myocardial infarction (MI); thus, a method to discern the various zones would be of great value in clinical management. The traditional approach in treatment attempts to salvage the viable peri-infarcted areas, by pharmaceutical intervention. A popular route of treatment is providing Angiotensin Converting Enzyme inhibitors (ACEi) to reduce QT dispersion (QTd) following MI. Increased QTd is a marker of electrical instability predisposing to ventricular arrhythmias in the infracted areas. Captopril, an ACEi, is widely used as an effective reducer of mortality and morbidity following MI , primarily due to its ability to improve left ventricular remodeling following the cardiac event.The physiological effect of Captopril has on the peri-infarcted regions postMI has not been well interpreted. Studies show promise in the field of cardiac imaging using manganese as a contrast agent to track changes in tissue viability. In this study we would like to examine, using a murine model: (1) the sensitivity of manganese enhanced MRI (MEMRI) T1 mapping to detect peri-infarction sites, and (2) the sensitivity to differentiate preand postACEi treatment. This non-invasive imaging technique could provide a potential diagnostic method to monitor pharmaceutical intervention and therefore improve diagnostic assessment of ischemic damage, thus improving patient care.