A method of ablating tissue in the heart to treat
atrial fibrillation introduces into a selected atrium an energy emitting element. The method exposes the element to a region of the
atrial wall and applies ablating energy to the element to thermally destroy tissue. The method forms a convoluted
lesion pattern comprising elongated straight lesions and elongated curvilinear lesions. The
lesion pattern directs electrical impulses within the atrial myocardium along a path that activates the atrial myocardium while interrupting reentry circuits that, if not interrupted, would cause
fibrillation. The method emulates the surgical maze procedure, but lends itself to
catheter-based procedures that do not require open heart surgical techniques. A
composite structure for performing the method is formed using a template that displays in planar view a desired
lesion pattern for the tissue. An array of spaced apart element is laid on the template. Guided by the template, energy emitting and non-energy emitting zones are formed on the elements. By overlaying the elements, the
composite structure is formed, which can be introduced into the body to ablate tissue using
catheter-based,
vascular access techniques.