Mechanism analysis of 2 µm thulium-doped picosecond laser ablation on myocardial tissue in minimizing thermal injury

In this work, we introduced a fully fiber-integrated 2 µm thulium-doped laser system and conducted parametric analysis and mechanism studies on myocardial tissue ablation using this laser. Fresh porcine myocardial tissue served as the model, allowing precise adjustment of laser power (1.0-3.0 W) and scanning speed (1-2.5 mm/s). Ablation experiments were conducted under controlled conditions, assessing ablation morphology, thermal damage, element distribution, chemical composition, and pathology. Finite element models for temperature fields and ablation theory were established. Simulation results indicated a significant influence of laser parameters on ablation outcomes. Controllable ablation was achieved by adjusting parameters. Experimental results showed a maximum ablation depth of 0.55 mm, an ablation area of 4.07 mm², and a minimal thermal damage area of 1.02 mm². This study provides insights into parameter optimization and ablation mechanisms, confirming the potential of a 2 µm thulium-doped picosecond laser for precise and minimally invasive cardiac interventions.