Abstract: A probe for the stimulation of the left atrium that is implantable in the coronary venous network for use with an active implantable medial device, in particular a pulse generator of “multisite” type. The probe is a tripolar probe including a cylindrical body provided, in an electrode area located axially and remotely of its distal end, with a stimulation electrode (18) electrically connected to a first probe conductor (24), and two annular reference electrodes (20, 22), one distal (20) and one proximal (22) of the stimulation electrode, electrically connected together and to a second probe conductor (26). The stimulation electrode is axially disposed between the two reference electrodes and is an annular or a sectoral electrode. The probe comprises an electric connection body connecting the two reference electrodes (20, 22) to an internal conductor segment (36, 38) disposed in the area of the stimulation electrode but electrically isolated therefrom.

Abstract: A body implantable lead assembly includes a lead body and a tip electrode assembly at the distal end of the lead body. The tip electrode assembly is detachably connected to the lead body by means of a threaded coupling actuatable by a stylet inserted through the lumen of the lead body. The lead body may therefore be removed leaving behind a chronically implanted tip electrode assembly. The invention has particular utility in the context of passive endocardial heart pacing leads whose tip electrode assemblies include tines which become entangled in the trabecular network of the heart, and are therefore difficult to remove.