多物理场耦合下心脏射频消融热损伤形成机理的研究

Methods to control the size and shape of myocardial thermal lesion are critical clinical issues to be urgently solved. This project takes the real anatomic structure of the atrium as a base and is proposed to build up thermal lesion models due to cardiac radiofrequency ablation (RFA) under couplings of multiple physical fields. Physical indexes dominated by myocardial thermal lesion is going to be analyzed on the basis of the description of the formational mechanisms of myocardial thermal lesion, and accordingly the controlling strategies of thermal lesion will be expounded and verified by animal experiment. Scientific issues are extracted from clinical demands of atrial fibrillation (AF) in this project. Viscoelastic mechanical models of catheter-tissue contact, volume conductor models of radiofrequency electric field, flow field model of blood velocity and bioheat transfer models of myocardial temperature distribution will be constructed and correlated. Additionally, this project will research (a) the relationship between contact force as well as single source RF parameters and myocardial thermal lesion and (b) the characteristics of electric and thermal fields produced in myocardium under synchronous/asynchronous discharge with multiple source RF parameters, and also exposure the features of multiple source RFA. Outcomes of this project will not only have significant theoretical value by revealing the formational mechanisms of thermal lesion but also provide bases for clinical selection of AF ablation parameters/modes thus do improve the safety and effectiveness of RFA for AF.

如何控制心肌热损伤尺寸和形态是房颤射频消融迫切需要解决的重要临床问题。本项目基于真实心房解剖结构，构建多物理场耦合下的心肌射频消融热损伤模型。在阐明心肌热损伤形成机理的基础上，分析心肌热损伤控制的物理指标，提出消融热损伤控制策略；并通过动物实验验证。本项目根据房颤临床需求凝炼科学问题。构建并融合反映导管-心肌接触压力的黏弹性力学模型、反映心肌射频电场特征的容积导体模型、反映血流速度的流场模型和反映心肌温度分布的生物热传导模型。在计算机模型和消融实验的基础上，研究压力及单源射频参数与心肌热损伤的关系；研究多源射频参数及同步/异步放电模式在心肌中产生的电场及热场特征，阐明多源射频消融模式的特点。本项目的研究成果将不仅揭示复杂条件下消融热损伤形成的机理，具有重要的理论价值；而且可为临床房颤射频消融参数/模式的选择提供依据，有助于提高房颤消融的安全有效性。

精准控制心脏消融损伤是房颤消融迫切需要解决的重要临床问题。但射频电场消融的电学机制和损伤形成机理尚不完全清楚，临床实践中难以精准控制损伤尺寸和形态。本项目从房颤临床需求中提炼科学问题，基于真实消融手术中存在的多物理场，构建心脏消融损伤模型；建立并融合反映射频电场特征的容积导体模型、反映冷盐水灌注的流场模型和反映消融温度的生物热传导模型。阐明了消融损伤形成机理，分析了损伤控制的物理指标，提出了射频电场消融的最优放电策略；并通过消融实验验证。研究将导管接触压力、消融功率和放电时间作为自变量，心肌损伤深度作为因变量，建立了心肌热损伤量化消融模型；通过算法实现，将量化消融模型在医疗仪器中集成。本项目的研究成果不仅揭示复杂条件下消融损伤形成的机理，具有重要的理论价值；而且可为临床射频电场消融参数的选择提供依据，有助于提高房颤消融的安全有效性。