Developing an in vitro Experimental Protocol to Assess Biaxial Mechanical Behavior in Viable Esophageal Tissue During Ablation Stacking
Cardiac ablation is widely used to treat atrial fibrillation (AF). They employ thermal modes such as radiofrequency (RF), or cryoablation, which are known to alter tissue structure and mechanics, or non-thermal mode such as pulsed field ablation (PFA) that electrically isolates the tissue and are expected to preserve mechanical integrity. During ablation, tissues adjacent to the heart can also be affected, including the esophagus, due to its close anatomic proximity to the posterior left atrium. The mechanical behavior of esophageal tissue under various ablation techniques, and when multiple ablation methods are stacked, remains poorly understood.
Freshly harvested porcine and canine esophageal tissue samples are mounted on a biaxial testing platform under temperature regulated and oxygenated Krebs solution. Cyclic loading is applied along two orthogonal directions, and ablation energy delivered using respective catheters depending on modality. Load and displacement is recorded during preconditioning, ablation, and post-cycling, and analyzed using a MATLAB-based workflow to compute relative stiffness over time. Additionally a sample in a tissue bath with electrical stimulation is used to verify viability. Relative stiffness showed a gradual decrease over time, with visible increases during ablation. Post-ablation trends returned to a decreasing trajectory, with ongoing analysis to quantify modality-specific effects.
This study establishes a biaxial study methodology for evaluating the mechanical response of viable esophageal tissue under multi-modality ablation stacking. By enabling mechanical assessment under physiologically relevant conditions and over time, this work provides a foundation for understanding how sequential application of different ablation modalities influences tissue behavior and improves assessment of ablation safety in adjacent tissues such as the esophagus.