Radiofrequency ablation-Real-time visualization of lesions and their correlation with underlying parameters

Area of Science:

• Cardiovascular Interventions
• Medical Device Technology
• Electrophysiology

Background:

• Successful radiofrequency (RF) ablation requires durable and transmural lesions.
• Real-time visualization of RF lesions is essential for procedural success.
• Understanding the role of local impedance (LI) in lesion formation is critical.

Purpose of the Study:

• To develop a model for real-time RF lesion visualization.
• To investigate the influence of local impedance (LI) on RF lesion formation.
• To analyze the impact of power and contact force on lesion characteristics.

Main Methods:

• Utilized a force-sensing, LI-sensing catheter in an ex vivo porcine cardiac model.
• Recorded lesion size and ablation parameters (power, contact force) second-by-second for 60 seconds.
• Analyzed 1847 measurements from 36 lesions under varying power (20-50W) and contact force (1-25g) settings.

Main Results:

• Lesion formation exhibited nonlinear growth, peaking in the first seconds (max. 1.08 mm/s depth, 2.71 mm/s diameter).
• Early lesion extent was primarily determined by power levels.
• Local impedance (LI) changes were most significant initially (up to -12 Ω/s) and diminished over time.

Conclusions:

• Irrigated RF ablation lesion formation is a nonlinear process.
• Initial rapid lesion growth significantly influences final lesion size.
• Local impedance (LI) serves as a reliable indicator for monitoring lesion formation changes.