Tissue poromechanical deformation effects on steam pop likelihood in 3-D radiofrequency cardiac ablation

Abstract

Radiofrequency Cardiac Ablation (RFCA) is a common procedure that heats cardiac tissue to destroy abnormal signal pathways to eliminate arrhythmias. The complex multiphysics phenomena during this procedure need to be better understood to improve both procedure and device design. A deformable poromechanical model of cardiac tissue was developed that coupled joule heating from the electrode, heat transfer, and blood flow from normal perfusion and thermally driven natural convection, which mimics the real tissue structure more closely and provides more realistic results compared to previous models. The expansion of tissue from temperature rise reduces blood velocity, leading to increased tissue temperature, thus affecting steam pop occurrence. Detailed temperature velocity, and thermal expansion of the tissue provided a comprehensive picture of the process. Poromechanical expansion of the tissue from temperature rise reduces blood velocity, increasing tissue temperature. Tissue properties influence temperatures, with lower porosity increasing the temperatures slightly, due to lower velocities. Deeper electrode insertion raises temperature due to increased current flow. The results demonstrate that a 5% increase in porosity leads to a considerable 10% increase in maximum tissue temperature. These insights should greatly help in avoiding undesirable heating effects that can lead to steam pop and in designing improved electrodes.

Comparative analysis of RADAR vs. conventional techniques for AVF maturation in patients with blood viscosity and vessel elasticity-related diseases through fluid-structure interaction modeling: Anemia, hypertension, and diabetes

“…Where u v , v v , w v represent the displacement of vessel(mm), ρ v is vessel density (kg/m 3 ), σ is the stress (N/m 2 ), τ is wall shear stress (N/m 2 ), and f F is applied body force from fluid (N). The equilibrium equations for solid mechanics, written in a Cartesian coordinate system, are [ 72 , 73 ]: …”

“…The stress–strain relationship (Eq ( 10 )) and the strain-displacement relationship (Eq ( 11 )) are as follows [ 72 , 73 ]: where ε denotes the mechanical strain, E is Young’s modulus (Pa), ν is the Poisson’s ratio. The mechanical strain is calculated by Young’s modulus (Pa) and the Poisson’s ratio, where demonstrate in Table 1 .…”

“…The stress-strain relationship (Eq (10)) and the strain-displacement relationship (Eq (11)) are as follows [72,73]:…”