Background: Ischemic heart disease is the leading cause of death in the United States, Canada, and worldwide. Severe disease is characterized by coronary artery occlusion, loss of blood flow to the myocardium, and necrosis of tissue, with subsequent remodeling of the heart wall, including fibrotic scarring. The current study aims to demonstrate the efficacy of quantitating infarct size via 2D echocardiographic akinetic length and 4D echocardiographic infarct volume and surface area as in vivo analysis techniques. We further describe and evaluate a new surface area strain analysis technique for estimating myocardial infarction (MI) size after ischemic injury. Methods: Experimental MI was induced in mice via left coronary artery ligation. Ejection fraction and infarct size were measured through 2D and 4D echocardiography. Infarct size established via histology was compared to ultrasound-based metrics via linear regression analysis. Results: 2D echocardiographic akinetic length (r = 0.76, p = 0.03), 4D echocardiographic infarct volume (r = 0.85, p = 0.008) and surface area (r = 0.90, p = 0.002) correlate well with histology. While both 2D and 4D echocardiography were reliable measurement techniques to assess infarct, 4D analysis is superior in assessing asymmetry of the left ventricle and the infarct. Strain analysis performed on 4D data also provides additional infarct sizing techniques, which correlate with histology (surface strain: r = 0.94, p < 0.001, transmural thickness: r = 0.76, p = 0.001). Conclusions: 2D echocardiographic akinetic length, 4D echocardiography ultrasound and strain provide effective in vivo methods for measuring fibrotic scarring after MI.
Soft Robotics: Autonomous Motility of Polymer Films (Adv. Mater. 7/2018)
