Atrial ablation with an IRK-151 infrared coagulator

Background. The purpose of this study was to develop a method of atrial ablation. In the IRK-151 infrared coagulator, light from a tungsten-halogen lamp is focused into a quartz rod. The distal exit plane is connected to a tip made of sapphire to allow linear ablation. Methods. Thirty-six lesions were created in 9 mongrel dogs. The beating ventricular myocardium was ablated from the epicardium. In each dog, 4 lesions were created by using the following durations of application: 3, 9, 15, and 21 seconds. After the ablation, the myocardium was fixed and stained. A linear lesion on the beating right atrial free wall was created. Before and after the ablation, epicardial plaque–electrode mapping was performed. Three months after ablation, remapping was performed. Results. The ablated myocardium had well-demarcated necrosis without carbonization or vaporization. The maximum depth was 10.3 ± 0.8 mm. The conducting pathway was blocked. The block, once made, continued for 3 months. Conclusions. The IRK-151 produces well-demarcated lesions that were deep enough for atrial ablation to block the conducting pathway.