An intraseptal multi-electrode cardiac pacemaker has a plurality of first individual electrodes implanted at an interventricular septum at varying depths and/or lateral distances from the distal end of a flexible conduit and configured to provide a cardiac pacing therapy by stimulating left bundle branch conduction fibers. A plurality of second individual electrodes may also be implanted in the septum at suitable depths to stimulate conduction fibers of the right bundle branch. After implantation, first and second individual electrodes are interrogated to select a subset of electrodes suitable to deliver the pacing therapy according to a predetermined criterion such as capturing the left ventricle or capturing the right ventricle via normal conduction system of the heart at the lowest voltage level via corresponding bundle branches. A combination of the pacemaker with a cardioverter/defibrillator is provided by positioning a defibrillator coil near the distal end of the flexible conduit of the pacemaker.
