An apparatus includes a flexible lead body extending from a proximal end to a distal end, an expandable electrode coupled proximate the distal end, the expandable electrode having an expanded diameter dimensioned to abut a wall of a pulmonary artery, and an implantable pulse generator electrically coupled to the expandable electrode. The expandable electrode includes a plurality of electrode zones. The plurality of zones can be tested to determine which zone delivers the best baroreflex response. At least one of the electrode zones can be selected to deliver a stimulation signal based on the testing. The implantable pulse generator is adapted to deliver a baroreflex stimulation signal to a baroreceptor in the pulmonary artery via the electrode.
