Linear atrial ablation with a diode laser and fiberoptic catheter.

The catheter maze procedure for the treatment of chronic atrial fibrillation requires the creation of transmural, continuous linear atrial lesions. Attempts to drag a conventional radiofrequency ablation catheter across the atria in clinical as well as experimental studies have resulted in discontinuous lesions. Continuous linear lesions have been most difficult to create in trabeculated atrial muscle. Lesion discontinuities or gaps have resulted in reentrant atrial tachyarrhythmias in patients after ablation. We have explored the use of a linear laser catheter for the creation of continuous atrial lesions. A linear laser system may offer a number of potential advantages over conventional radiofrequency catheter ablation: (1) the laser diffuser is a single flexible and compliant fiber that can create thin lesions; (2) continuous intimate contact between the catheter and the endocardium may not be essential for delivery of laser energy; (3) the laser diffuser is Teflon coated, is not directly heated during energy delivery, and thus is not prone to char formation on the catheter; and (4) laser energy delivery is not subject to disruption by rises in impedance. We tested the feasibility of percutaneously creating a line of conduction block on the trabeculated anterior wall of the right atrium with a diode laser in a goat model. These images (Figure) demonstrate that linear atrial conduction block can be effectively achieved by catheter ablation with thermal energy sources other than conventional radiofrequency current.