Transmural ablation tool and method

Abstract

An ablation method and device contacts one surface of a target layer and positions the tissue to ablate entirely through the layer. The tissue may be a wall of the heart (ablated, for example, to form blocking lesions for atrial fibrillation), and ablation may be performed with the heart stopped or beating, and effected by either endocardial or epicardial contact. Access may be through an open incision or a minimally invasive technique involving a small opening through which one or more elongated surgical tools are inserted. Illustratively, an atrial ablation treatment can be performed prophylactically (after CABG), or independently to treat an existing condition. A tool of the present invention has a handle at a proximal end, a bipolar ablation head, and an elongated body interconnecting the handle and the ablation head. A channel or contoured surface fixes and bends the tissue such that inter-electrode conduction paths span the thickness of the layer, thus dependably creating a fully transmural ablation lesion. The oriented transmural energy conduction paths reduce the possibility of inducing coagulation of blood in the heart chamber. One bipolar assembly has an electrode spacing of approximately ten millimeters across a channel of about five millimeters depth. Preferably the ablation head forms a suction holder, connected through internal passages to a vacuum pressure of about 100-500 mmHg, and immobilizes the contacted tissue.