Apparatus (170) for heart pacing with hemodynamic improvement, including oneor more electrodes (36), which convey electrical signals to respective cardiacmuscle segments. Signal generation circuitry (50) applies an extended pacingsignal (60, 61), having an overall duration greater than three times achronaxie time, to the one or more electrodes so as to pace the heart. Thesignal preferably includes a train of a plurality of biphasic pulses, and hasan amplitude at least three times as great as a threshold for pacing theheart, but not sufficient for cardioversion.
