The present invention relates to an anchor device (10) comprising an elongated tubular body (12) having an expandable member (14) disposed on its distal end portion. The invention also relates to a system adapted to position and anchor the distal end of an ablation device (80) at a location where a pulmonary vein extends from the atrium, wherein the ablation device (80) is adapted to slidably engage and track over the anchor device (10), such that the ablation device can be ablatively coupled to a region of tissue by advancing the ablation device distally over the anchor device.
