Abstract:
"A Novel Method for Quantifying the In-Vivo Mechanical Effect of Material Injected Into a Myocardial Infarction"
This study develops a biomechanics-focused finite element framework to quantify the in vivo mechanical impact of injecting a calcium hydroxyapatite–based filler into myocardial infarctions. Patient-specific left ventricular geometries were reconstructed from real-time 3D echocardiography in a sheep model, meshed with eight-node brick elements, and partitioned into infarcted and remote regions. Passive behavior was represented by a transversely isotropic hyperelastic strain-energy function, while active contraction employed a time-varying elastance model. Material parameters were calibrated by matching measured end-diastolic and end-systolic volumes and enforcing near-zero radial strain in the treated infarct, yielding a passive stiffness increase of ~345× in the infarct zone and suppression of active stress to reflect akinesia. Simulations showed that filler-induced stiffening elevated ejection fraction from 35% to 53% and reduced peak myofiber stresses by up to an order of magnitude, thereby mitigating key biomechanical drivers of adverse remodeling.
