Using EKG to Confirm MI in Mouse Model of Permanent Left Anterior Descending Coronary Artery

Abstract

The variability in coronary artery anatomy and branching of the left coronary artery can affect reproducibility of myocardial infarction (MI) surgery, even with occlusion at a constant anatomic site. Blanching and discoloration of the left ventricle (LV) are common variables used to confirm a successful MI surgery. Determining a way to improve precision will improve the standard surgical approaches to simulate MI in mice, thus reducing the number of experimental animals necessary for statistically relevant studies. In this study, we hypothesized that using a threshold change in electrocardiography (EKG) can verify correct ligation and successful MI surgery. Using the Indus Rodent Surgical Monitor+, we measured the EKG pre and 30 sec post-MI in C57Bl6/J mice (n=13). Mice were grouped based on infarct size determined by Tetrazolium chloride (TTC) staining (n=8 with infarct ≥35%; n=5 with infarct ˂ 35%). Area under the QRS curve (p=0.008) and ST elevation (p=0.009) were significantly different pre versus post-MI in mice that had at least 35% infarct. No correlation was observed between infarct size and change in area under the QRS complex (R2=0.205; p=0.308) nor ST elevation (R2=0.089; p=0.516). Receiver operating characteristic (ROC) curve analysis demonstrated that the change in ST elevation could accurately predict MI surgery success (Area= 0.84; p=0.062). In conclusion, our data demonstrates that changes in voltage of the ST segment can predict accuracy of MI surgery.