2 - Guiding Lesion Formation During Radiofrequency Catheter Ablation

Abstract

Titrating radiofrequency (RF) energy in cardiac catheter ablation procedures is a key component of creating effective, durable lesions while minimizing the risk of procedural complications. Because RF catheter ablation requires stable contact between catheter tip and myocardial tissue, this must be assessed in real-time using fluoroscopy, tactile feedback, electrogram characteristics, or direct measurements of contact force available on some ablation catheters. Titrating energy delivery can eliminate conduction in targeted tissue while minimizing the risk of coagulum formation, steam pop, and cardiac perforation. Aside from delivering the appropriate power, collateral damage to nearby structures, such as the atrioventricular node, esophagus, and phrenic nerves, can be prevented by monitoring for unwanted heating. There are different methods of guiding RF energy delivery, such as monitoring ablation electrode temperature, changes in ablation circuit impedance, contact-force-derived parameters, and electrogram amplitude reduction, each with specific advantages and limitations. When using large-tip and irrigated-tip catheters, special precautions should be taken to avoid excessive myocardial heating and collateral damage, because there is a greater discrepancy between catheter-tip temperature and myocardial tissue temperature. When performing RF ablation in other sites besides endocardial surfaces of cardiac chambers, such as in the pericardial space or coronary sinus, changes to the general power titration approach are recommended.