Abstract 3224: Optical Coherence Tomography Imaging of Radiofrequency Ablation Lesions
Background: Cardiac arrhythmias are abnormalities of the electrical conduction of the heart and occur in patients of all ages with and without heart disease, compromising heart function. Catheter ablation using radiofrequency (RF) energy is commonly used as a non-pharmacological strategy in clinical electrophysiology to destroy or block abnormal conduction pathways to treat cardiac arrhythmias. Presently, no method is available to directly monitor lesion formation in real-time. Optical Coherence Tomography (OCT) is a non contact imaging modality that can generate three dimensional images in real time with micron-scale spatial resolution. OCT detects minimally scattered light and utilizes intrinsic scattering contrast (index mismatch) within samples to generate an image to a depth of 1–2 mm in cardiac tissue.
Methods and Results: In-vitro ablation experiments were conducted on wedges of canine heart placed in a flow chamber. The parameters that were investigated were power, frequency, and angle of the catheter with respect to the surface, and the location and duration of the exposure. A microscope-coupled OCT system was used to image the samples. A 1310 nm light source with 70 nm resolution was used. The axial and lateral resolution of the system was approximately 10 micrometers (in air). Thermal lesions and necrosed tissue appears more highly scattering (‘white’) in OCT images, and can be readily differentiated from the healthy myocardium. An OCT scanner that accommodates an ablation catheter was developed. The integrated instrumentation allowed observation of the lesion formation in real-time .
Conclusion: Ablation lesions can readily be distinguished from the healthy myocardium using OCT imaging. OCT provides real time monitoring of lesion formation with high resolution, allowing direct visualization of ablation lesion formation. This technology will aid investigation of thermal lesion formation, and may have clinical application in arrhythmia therapy.